18th Congress of the European Society for Agronomy

Aug 26, 2024, 4:00 PM → Aug 30, 2024, 5:00 PM Europe/Paris

The Couvent des Jacobins

Edith LE CADRE (member), Matthieu CAROF (member), Olivier GODINOT (member)

Welcome to the 18th Congress of the ESA in Rennes, France!

Organised by l’Institut Agro Rennes-Angers, in collaboration with INRAE

Synergies for a resilient future: from knowledge to action

The European Society for Agronomy (ESA) aims to promote the exchange of scientific and practical experience between experts in agronomy. Today, more than ever, we need to dialogue between peoples, between society and science and between all the disciplines that contribute agronomy because transformation of our agricultural systems is not an option, it is our future.   
The aim of the 18th Congress of the ESA in Rennes, France in August 2024 is to vertebrate transformation in agricultural systems with new alliances, and synergies.   
This congress follows on from the highly successful 17th congress held in Postdam, Germany, which gathered over 246 participants worldwide. We hope to repeat this success in Rennes and further strengthen our network. 

Prof. Dr. Edith Le Cadre, on behalf of the Scientific committee and the Local organising committee

18thESA-template.pptx

ESA2024-Book_of_Abstracts.pdf

mapCouvent.pdf

programmeESA_240823.pdf

Monday, August 26

Registration

Welcome speech: after the welcome speech, there will be a welcome drink (18:45-19:30) with a soloist on the Celtic harp

Convener: Edith Le Cadre

openingSession_LeCadre.pdf

Tuesday, August 27

Registration

Welcome speech

Convener: Edith Le Cadre

openingSession_LeCadre.pdf

Co-creation of knowledge and transformations in agri-food systems - Johanna Jacobi

Convener: Edith Le Cadre

ESA2024_keynote_Jacobi.pdf

1 Co-creation of knowledge and transformations in agri-food systems

Speaker: Johanna Jacobi (ETH Zurich)

ESA2024_keynote_Jacobi.pdf

10:50 AM Coffee break

Cropping systems changes to support agro-ecological transitions

Conveners: Julie Ryschawy, Charlotte Simon

2 Is crop diversification an efficient approach to reduce pesticide use?

Diversifying crop rotations in arable farming is considered as an option to regulate weeds, pests and diseases, and therefore to decrease the need for pesticides. However, the potential for reducing the reliance on pesticide through crop diversification had, so far, not been quantified at the cropping systems scale. In this study, we analysed this relationship from 1285 cropping systems described from 795 arable farms of the French DEPHY network. Crop diversity was assessed in each cropping system through the number of crops grown in the pluriannual crop sequence. The reliance on pesticides was measured with the Treatment Frequency Index (TFI), averaged over the same crop sequence. The relationship between TFI and the number of crops displayed a bell-shape curve, with maximum pesticide use for intermediate number of crops. This relationship was strongly driven by the nature of crops grown which varies with crop diversity. Indeed, monocultures were always based on maize, a crop with a rather limited reliance on pesticides in France. Two-crop rotations were often based on maize and wheat (a crop with an intermediate-high reliance). Three-crop rotations introduced oilseed rape (a crop with a higher reliance) while four-crop sequences introduced sugar beet (a crop with a high reliance) and potato (the crop with the highest reliance). On the other hand, the proportion of crops with low to very low reliance on pesticides (such as oat, buckwheat, and temporary grasslands) increased in cropping systems with higher diversity. Since the reliance on pesticides varies drastically across crops (examples of average TFI: 13.5 for potato, 5.5 for sugar beet, 4.8 for oilseed rape, 3.3 for soft wheat, 1.8 for sunflower and maize, 0.6 for alfalfa and 0.4 for buckwheat), the nature of crops grown is a major factor explaining 37% of TFI variance over the whole data set.
We removed the effect of the nature of crop grown by computing the difference between the actual cropping system TFI and the ‘predicted’ system TFI (weighted average of mean crop TFIs with weight being the proportion of each crop in the cropping system). This reveals that increasing crop diversity significantly decreased pesticide use by -0.09 TFI per additional grown crop (Figure 1). Finally, crop diversity accounted for only 1% of total TFI variance. The remaining variance can be explained by many other factors not considered in this analysis, but known to drive the level of pesticide use (Lechenet et al., 2016) such as climate, soil type, pest pressure, cultivars, sowing dates, fertilisation, mechanical weeding, and strategy for decision to apply treatments.
The significant effect of crop diversity on pesticide use was lower than expected, particularly when compared to previous quantifications of the regulation of pests through crop diversity (Ratnadass et al., 2012; Kremen & Miles, 2012; Larsen & Noack, 2021). Indeed, pest regulation due to diversification can be significant, but not strong enough to impact pesticide use if the regulation does not decrease pest pressure below the thresholds applied by farmers when making the decision of treatments. Analysing pesticide use at the crop level, Guinet et al. (2023) also found significant but quite low effects of cropping system diversity, consistently with our results. However, the number of crops is probably not the best indicator of diversity regarding the impact on pest regulation and pesticide use, so further investigation is planned to compare indicators integrating the functional crop diversity.

Figure 1. Difference between observed and predicted cropping system TFI as a function of crop number.

References
Lechenet et al. (2016). Profiling farming management strategies with contrasting pesticide use in France. Agricultural Systems, 149, 40–53.
Ratnadass et al. (2012). Plant species diversity for sustainable management of crop pests and diseases in agroecosystems: A review. Agronomy for Sustainable Development, 32(1), 273–303
Kremen & Miles (2012). Ecosystem services in biologically diversified versus conventional farming systems: benefits, externalities, and trade-offs. Ecology and Society, 17, 342
Larsen & Noack (2021). Impact of local and landscape complexity on the stability of field-level pest control. Nature Sustainability, 4, 120–128.

Speaker: Nicolas Munier-Jolain (Agroécologie, INRAE, Institut Agro, Univ. Bourgogne, Univ. Bourgogne Franche-Comté, Dijon, France)

3 Current coupled innovations for glyphosate-free agricultural systems

Context description and research question: Reducing pesticide use such as glyphosate, is a key challenge to support agroecological transition and resilience of farming systems. However, politicians and scientists argue that in certain situations, which they describe as "dead-ends", reducing glyphosate use is particularly difficult because of structural barriers (Reboud et al., 2017). Then, our aim was to shed light on innovations from farmers – focus on technics, equipment and collective action - to reduce the use of glyphosate in two “dead-ends” situations: slopping vineyard and low-till cropping system.
Method and theoretical background: We adapted a tracking on-farm innovation method (Salembier et al., 2021): (i) We identified 16 cases through exploring databases, professional agriculture press, and contacting extension agencies. (ii) We performed semi-structured interviews with farmers about innovation. (iii) We analyzed the systemic nature of innovation thanks to an in-depth inductive analysis of each case, relied on the concepts of coupled innovation (Meynard et al., 2017) and of action logic (Salembier et al., 2021). (iv) We built typologies through a cross analysis of the case studies.
Results and discussion: Three major results emerged: (i) We characterized five types of innovation on collective action that supported farmers’ access to key levers in weed management: 1) sharing resources (e.g. equipment, land, herd); 2) sharing labor (e.g. shared employee); 3) sharing technical management decision (e.g. collective decision in a common crop rotation); 4) developing a new resource (e.g. self-building an equipment adapted to sloppy vineyards); 5) accessing agricultural services. This typology corroborates and enhances the findings of Lucas et al. (2018). (ii) We identified three types of innovation on equipment to perform weed management: 1) flexible use of an equipment (e.g. a seed drill for sowing on straw and on cover crops); 2) combining equipment to perform two tasks at the same time; 3) designing and building a new equipment (e.g. under-vine mowing tool for terraced vineyard). (iii) We identified 3 types of coupled innovations. In vineyard: i) managing perennials on moderate to steep slopes (>30%), which is based on frequent tillage, using combinations of equipment (5 cases); ii) managing perennials on steep slope vineyards (30%) by covering the soil in inter-rows and employing moderate tillage under vine, which involves shared equipment and/or workforce (2 cases); and iii) weed management in terraced vineyards (30-40%) while limiting erosion and mitigating the challenges associated with working on steep slopes, through the use of self-built and shared equipment (2 cases). In cropping system: i) coordinating management of crops and livestock, which involved a few field interventions for weed management while also contributing to livestock feeding (e.g., grazing on cover crops) and cost reduction (3 cases); ii) minimizing the harmfulness impact of weeds through the increase diversification of crop rotation, sharing equipment and/or workforce (2 cases); iii) eliminating weed in monoculture by employing precision equipment, as well as pooling workforce (2 cases). Our findings enrich the literature on coupled innovation in weed management strategies (Boulestreau et al., 2022), and it provides evidence on how these systemic innovations work to address technical and organizational issues, which allowed farmers to manage weeds and cover crops in situations considered as strongly dependent on glyphosate in “dead-ends” situations. The innovations identified could inspire other farmers engaged in the redesign of their farming systems to be free from glyphosate.

Speakers: Dr Priscila Duarte Malanski (INRAE), Dr Marie Thiollet-Scholtus (INRAE)

40_Duarte-Malanski.pptx

4 Reducing reliance on pesticides through redesigned crop management strategies has contrasting effects on economic performance across farm types

Introduction
Intensive use of pesticides in agriculture has led to negative impacts on human and ecosystem health, and to policies aiming at reducing their utilization. Alternative non-chemical pest control strategies, based on holistic Integrated Pest Management implemented in real commercial farms, have been shown to substantially reduce the reliance on pesticides (Nandillon et al., 2024). Yet, such strategies have remained poorly adopted, partly due to farmers’ risk aversion and the general belief that using less pesticides reduces farm productivity and profitability. Bringing clarity on the link between cropping practices used to reduce farm reliance on pesticides and farm outcomes is needed to support practitioners in a transition towards a more sustainable agriculture.

Methods
We explored detailed data from the DEPHY network, describing cropping system and crop and pest management in 904 commercial French farms classified into eight farm types over an average period of 9.2 years. We investigated the effects of non-chemical crop management practices used to reduce farms’ reliance on pesticides on three metrics of farm economic performances, namely margin (€/ha), production of energy (MJ/ha) and resource use efficiency (Total Factor Productivity). The marginal effect of the change in reliance on pesticides on the change in margin and gross-product was analyzed across the eight farm types. The economic feasibility to reach the 50% objective in pesticide use reduction set by the French Ecophyto National Action Plan and the Farm to Fork strategy was investigated.

Results
On average, farm reliance on pesticides was reduced by 20% and farm profitability by 13% (-100€/ha) over the studied period. Cropping practices implemented in order to reduce reliance on pesticides had contrasting effects depending on the productivity metrics used and farm type. Crop diversification was positively associated with Total Factor Productivity and had positive build-up effects on margin. Tillage intensity had positive effects on margin and production of energy. There were farms that reduced reliance on pesticides with increased margin and gross-product in all farm types but this portion differed across farm types. Farms growing large quantities of high value-added crops such as sugar beet and potato most often showed the highest reductions in both gross-product and margin. Increases in margin and gross-product with reductions in the reliance on pesticides occurred most often in farms with much grasslands. Reducing farms’ reliance on pesticides by 50% would decrease farm profitability by a further 80 €/ha on average.

Caption for the figure attached:
Figure 1. a. Evolution of profitability (y axis) and evolution of the reliance on pesticides (x axis), for 904 farms, over an average period of 9.2 years. The size of the point is proportional to the initial level of reliance on pesticides of the farm and colors correspond to four performance categories. b. Map of the eight farm types used in this study.

Discussion
This study brings insight into the consequences on farm economic performances of transitioning to an agriculture using less pesticides. The contrasted effects of reductions in the reliance on pesticides on productivity metrics across farm types illustrate the need to consider multiple aspects of farm productivity when evaluating agricultural sustainable transition. Our results shed light on key crop management practices that should be incentivized by policy makers in order to make progress towards a more sustainable agriculture.

References
Guichard, L., Dedieu, F., Jeuffroy, M.-H., Meynard, J.-M., Reau, R., Savini, I., 2017. Le plan Ecophyto de réduction d’usage des pesticides en France : décryptage d’un échec et raisons d’espérer. Cah. Agric. 26, 14002. https://doi.org/10.1051/cagri/2017004
Nandillon, R., Guinet, M., Munier-Jolain, N., 2024. Crop management strategy redesign enables a reduction in reliance on pesticides: A diachronic approach based on a diversity of French commercial farms. Agric. Ecosyst. Environ. 366, 108949. https://doi.org/10.1016/j.agee.2024.108949

Speaker: Romain Nandillon (Institut Agro Dijon - INRAE UMR Agroécologie Dijon)

5 Trade-offs in circular agriculture

Introduction
Principles around circular agriculture are based on re-using by-products, closing nutrient cycles, minimal feed-food competition, low energy use and low GHG emissions [1]. Moving from current linear to more circular systems is a wicked problem as key trade-offs need to be overcome [2]. The objective here is to provide quantitative insights into such trade-offs and discuss consequences.

Methods
We have quantified all N and P flows in the North of the Netherlands (NN) as a starting point to assess the options to improve circularity [3]. Agricultural flows were based on data at farm level and aggregated to municipality level. Flows from processing, consumption, waste and residues were derived from statistical data complemented by available detailed studies. In a next step, future options for integrated crop-livestock systems (ICLS) were evaluated in which feed import and environmental constraints were varied and gross margin was maximized using a linear optimization model [4]. Lastly, trade-offs between land requirements and N intensity in mixed faring systems were assessed for mainstream and organic systems.

Results
Within the NN region, farms but also municipalities were specialised. At food system level, losses for N ranged from 181-480 kg ha-1 while P losses were 7-31 kg ha-1. Losses were largest in agriculture while recycling of nutrients in the food system was limited. The nutrient use efficiency was 25% for N and 59% for P, reflecting an inefficient and strongly linear system. Moving towards circular agriculture is expected to reduce these nutrient losses. However, potential benefits are not self-evident ICLS without constraints on NH3 and GHG emissions increased gross margins due to more animals and a larger proportion of intensive crops, resulting in more feed and N imports and consequently more emissions. In scenarios with NH3 and GHG emission constraints livestock strongly reduced, whereas more cash crops were grown. This negatively affected the gross margin of animal production system, while crop production systems benefitted. Also reducing N intensity increased land requirements exponentially for mainstream systems, while or organic systems least land was required at an N intensity equivalent to 90% of maximum yields.

Discussion
Re-integration of specialised crop and livestock systems is a key component of a more circular agriculture. Yet, it comes with trade-offs: ICLS without environmental constraints increases intensity [5]. This work shows that ICLS without limits for NH3 and GHG increases gross margins, but does not result in desired environmental outcomes and increases feed-food competition. An increase in food-feed competition reduces the area that can be set aside for conserving biodiversity, further amplified when mineral N inputs are reduced or replaced by leguminous cut-and-carry crops. Apparent ecosystem services at farm level by decreasing feed and mineral N inputs may be disservices at the regional scale due to increased feed-food competition. Addressing such undesired feed-food competition and spare land for biodiversity in a circular system requires a shift in diets with a smaller proportion of animal products [6].
Van Selm et al. [6] found that reducing feed imports to the Netherlands strongly reduces NH3 emissions and GHG emissions. We found the same for ICLS: restricting feed imports or imposing NH3 and GHG emission limits strongly reduced the number of animals and feed requirements. This also implies that the gross margins of livestock sectors decreases. Furthermore, such constraints reduced feed-food competition and increases the available area for cash crops [4], with benefits for cropping sectors.
Current animal production systems in areas with access to cheap feed are very competitive on export markets. Including environmental costs in feed imports through Europe’s harbours and pricing GHG emissions are key components to reduce profits and address environmental problems. Resulting revenues can be used to compensate incomes via targeted ecoservice payments that are needed to maintain specific habitats that are only found on low intensity farmland. We conclude that policies to address environmental impacts without changing the economic incentives for farmers are rowing against the current.

References
1. Muscat et al. 2021. Nature Food, 2021: https://dor.org/10.1038/s43016-021-00340-7.
2. Termeer and Dewulf 2019. Policy Soc.: https://doi.org/10.1080/14494035.2018.1497933.
3. Tamsma et al. 2024. Nutr. Cycl. Agroecosyst.: https://doi.org/10.1007/s10705-024-10352-x.
4. Alderkamp et al. Under review, 2024.
5. Schut, et al. 2021. Front. Agr. Sci. Eng.: https://doi.org/10.15302/J-FASE-2020373.
6. van Selm et al., 2023. Sci. Tot. Env.: https://doi.org/10.1016/j.scitotenv.2023.165540

Speaker: Dr Antonius G.T. Schut (Wageningen University and Research)

6 2023: a soil odyssey–HeAted soiL-Monoliths (HAL-Ms) to examine the effect of heat emission from HVDC underground cables on plant growth

Introduction: Renewable energies for sustainable and climate-neutral electricity production are on the rise worldwide. High-voltage direct-current (HVDC) transmission via underground cables gains influence to connect large production sides with consumer regions. In Germany, almost 5,000 km of new power line projects with an initial start date of 2038 or earlier are planned. During transmission, heat is emitted to the surrounding soil, but how this heat affects root growth and yield of the above crop plants is not well known and needs research.

Material & Methods: For that purpose, we designed and constructed a low-cost large HeAted soiL Monolith (HAL-M) for simulating heat flows within a natural soil composition and density. 24 HAL-Ms with a height of 1.56 m and an approximate diameter of 0.56 m were built for this experimental setup. Each contained approximately 400 kg of soil, with a planting area of 0.177 m2. The foundation of the twelve HAL-Ms was a barrel roller (HBR10, Hillesheim), equipped with a built-in heater. The HAL-Ms were filled with natural top- and subsoil extracted from two different sites near Bernburg and Merseburg (Germany, Saxony-Anhalt), representing the two different regional soil types 12x LOESS and 12x SAND as factor SOIL. For the factor TREATMENT, half of the HAL-Ms with LOESS and half of SAND were heated with constant 50° C (6x HEAT), and the other served as the control group (6x CTRL). For the factor RAIN, three levels (2x DRY 407 mm, 2x MID 528 mm and 2x WET 679 mm) were calculated based on data from 1988 to 2018 by the German Meteorological Service (DWD). We were able to observe root growth, soil temperature and soil water content over an extended time period. The plants were cultivated in three successive growth phases (GPs) simulating crop rotation. To avoid the need for vernalization, spring barley (Hordeum vulgare) GP1, sugar beet (Beta vulgaris) GP2 and spring wheat (Triticum aestivum) GP3 were cultivated.

Results: The yield of spring barley during GP1 under the SAND treatment was significantly reduced under the influence of HEAT (423.6 to 261.9 g m-2). RAIN also exerted a significant impact on the yield, with higher values under WET than under MID and the lowest yield under DRY. Moreover, HEAT reduced the yield under the LOESS treatment (without statistical certainty). In contrast to spring barley during GP1, the sugar beet yield was higher under the influence of heat emission, at least under the LOESS treatment (5609.0 to 6608.0 g m-2). RAIN imposed a significant impact on the yield, with the highest values under WET, declining from MID to DRY. There was no statistically significant difference between the CTRL and HEAT treatments for either soil type during GP3, although there was a slightly lower yield under the influence of heat emission. RAIN influenced the yield in a similar pattern to that of previous crops. There was no interaction effect between TREATMENT and RAIN on the yield during the single growth phases.
The root intensity during GP1 under simulated heat emission was significantly reduced at soil depths from 71.0 to 101.5 cm under the LOESSS and SAND treatments. In contrast to GP1, HEAT did not affect the intensity of sugar beet roots during GP2. During GP3, the root intensity at depths from 71.0–101.5 cm under the LOESS treatment was reduced under the influence of HEAT. There was a notable tendency for reduced root growth due to heat emission under the SAND treatment (p value=0.0585).

Discussion: We showed that under the simulated conditions, heat emission could reduce yield and root growth depending on crop type and soil. This experimental design can serve as a low-cost, fast and reliable standard to investigate thermal issues from cables of all kinds regarding various soil compositions and types, different precipitation regimes and several crop plants that are affected by similar projects. The HAL-M could serve as a link between pot and field trials with advantages of both and could be an enrichment for many research areas.

Figure 1: Construction of the HeAted soiL Monoliths (HAL-Ms). (a) Subsoil with black duct tape as a root barrier and two transparent tubes offset by 90°; (b) topsoil with an FDR sensor; and (c) finished HAL-Ms in the greenhouse.

Speaker: Ken Uhlig (Martin-Luther-University Halle-Wittenberg, Germany)

Uhlig.Ken - HeAted soiL-Monoliths -- HAL-Ms.pdf

7 How can we make biodiversity conservation an objective for farmers?

Introduction:
Growing awareness of the need to counter the erosion of biodiversity, coupled with political and social injunctions, are prompting rural stakeholders to build and manage agroecological farming systems in multifunctional landscapes. Biodiversity is a key component of these landscapes, which farmers are called upon to preserve and manage.
When asked about their interest in biodiversity, the majority of farmers say they are interested (Herzon and Mikk, 2007). However, this interest in biodiversity varies according to the taxa considered. For example, when it concerns birds or mammals, the majority of farmers would like to learn more about all species, except those known to cause damage to crops or livestock. When it comes to plants or insects, a distinction is made between "harmful" species and species of interest or tolerated. This perception of biodiversity also varies according to the type of farming considered. Kelemen et al (2013) have shown that organic farmers adopt a more philosophical and holistic vision of biodiversity, linking it to the notion of ecosystems and the interrelationships between the organisms that make them up. Beyond the different types of farming considered, the perception of biodiversity depends on the personal background of each farmer and his or her interests outside professional activity, as well as the more or less biodiversity-rich environment in which the farm is located.
As part of an interdisciplinary project involving agronomists and management scientists, we looked at how farmers integrated biodiversity management and protection into their farm management, and what benefits they derived from it. The biodiversity considered, how biodiversity is integrated into the farm's strategy, and the expected benefits, were related to the farmers' background, production system, and the relationships they developed around biodiversity.

Material and Methods:
Thirty farmers were interviewed. These farmers were recruited either directly, or with the help of naturalist associations, chambers of agriculture, or hunting federations. They are located in a wide range of soil and climate conditions and operate a variety of production systems (market gardening, arboriculture, livestock farming, mixed farming - livestock farming, and arable farming), both organic and non-organic.
The interviews were recorded and transcribed in full. The transcripts were double-coded to identify the nature of the biodiversity taken into account, its degree of integration into the farmer's strategy, and the determinants of the farmers' consideration of biodiversity (determinants internal and external to the farmer), as well as the expected benefits.

Results and Discussion:
Integrating biodiversity into farm projects engages farmers in a change of point of view, where biodiversity says something about the agroecosystem they manage. Whether to enhance the expression of ecosystem services (regulatory processes) or to conserve "wild" biodiversity on the farm. For some farmers, agronomical decisions are taken from a “biodiversity point of view”, by integrating temporal scales longer than that of the cropping season and spatial scales larger than the cultivated field. Their management strategies are guided by contextualized thinking, based on their knowledge of the functioning of their agroecosystems. From this point of view, the farmer's background is a key factor in the level of reasoning behind biodiversity conservation practices.
Whatever the category of farmers surveyed, biodiversity does not appear to be an economic issue for the farm, i.e. they do not expect any added value in the marketing of their production.
If we wish to integrate biodiversity conservation as an objective of the farm, in the same way as production, farmers need to reappropriate and recontextualize knowledge that they have little or no training in. Biodiversity then acquires a new meaning and says something about the agroecosystem they manage. Observation of how the agroecosystem works then becomes an imperative condition for change, an essential quality, not only for the pleasure of observing but also for taking ownership.

I. Herzon & M. Mikk (2007). Farmers’ perceptions of biodiversity and their willingness to enhance it through agri-environment schemes: A comparative study from Estonia and Finland. Journal for Nature Conservation, Volume 15, Issue 1. Pages 10-25. https://doi.org/10.1016/j.jnc.2006.08.001.

E. Kelemen, G. Nguyen, T. Gomiero, E. Kovács, J.P. Choisis, N. Choisis, M. Paoletti, L. Podmaniczky, J. Ryschawy, J.P. Sarthou, F. Herzog, P. Dennis, K. Balázs (2013). Farmers’ perceptions of biodiversity: Lessons from a discourse-based deliberative valuation study. Land Use Policy,Volume 35. Pages 318-328. https://doi.org/10.1016/j.landusepol.2013.06.005.

Speaker: Aude Barbottin (INRAE)

109-Barbottin.pdf

GxExM modeling

Conveners: Benjamin Dumont, Degbedji Charlemagne Aboua

8 Use of a crop growth model for supporting variety choice in sunflower

Crop growth models - or process-based models - simulate the dynamic responses of a range of varieties (G) as a function of environmental conditions (E) and management practices (M) and hence are appropriate tools to predict and explain G×E×M interactions (Chapman, 2008 ; Wang et al., 2019). Therefore such models could have practical applications for improving the design and analysis of multi-environment trials (METs) used for variety testing and help to identify specific fits between the tested varieties and their optimal cropping conditions (Jeuffroy et al., 2014). Developed for sunflower crop, the SUNFLO model (Casadebaig et al., 2011; Casadebaig et al., 2016) simulates performance-related variables (grain yield, seed oil concentration) and environmental-related indicators (abiotic stress effect on photosynthesis) of a wide range of varieties under contrasting cropping conditions. However it is not clear how actors in variety choice can integrate such models into decision support systems, and how their accuracy is impacted by operating crop growth models at a large geographical scale.

In this study conducted in the frame of a EU project aiming to foster the introduction of new varieties better adapted to varying biotic and abiotic conditions (H2020-INVITE, 2019-2024), the predictive accuracy of the SUNFLO model was evaluated over the key METs conducted in France for registration (GEVES) and post-registration (Terres Inovia) of sunflower varieties from 2003 to 2020, offering an unprecedented range of explored E, M and G modalities (1471 trials, 494 distinct cultivars).
While the model inputs related to management (sowing date, dates and amounts of N fertilization and irrigation) were directly collected from the structures that conducted the trials, the inputs related to climate and soil were derived from gridded public datasets. Daily weather data were systematically derived from the SAFRAN database (8 x 8 km cells) and soil data were extracted from the Geographic Database of Soils of France (millionth map). The cultivar-dependent parameters were collected from independent and routine trials conducted each year by INRAE and Terres Inovia. In this set of dedicated field and semi-controlled experiments, 9 parameters related to crop phenology, leaf architecture, plant response to water deficit, and biomass allocation were measured on a set of 133 cultivars.

Over these two trial networks, the flowering date (n = 3174), grain yield (n = 8652) and seed oil content (n = 6054) were predicted with an error (RMSE) of 5.9 days, 0.89 t/ha, and 5.9 % (relative error of 2 %, 27 % and 12 %, respectively). We concluded that grain yield prediction was not accurate enough to separate among elite varieties when using routine variety trials without additional data on the trial conditions (such as accurate weather records and a sound estimation of available soil water content).
While the model capacity to simulated GxE interactions was not granted, we showed that the simulated G and E effects were accurate separately. We proceeded by clustering trial locations and years into comparable environment-types based on the simulated abiotic stress patterns at trial level (Casadebaig et al., 2022). We showed that the sunflower growing area was composed of 4 types of situations (Figure): 45 % « cold », 30 % « optimal », 19 % « drought », and 6 % « heat ». This contextual information was embedded into a prototype of a decision-support system intended for choosing the best varieties (based on trial results) for each type of environment (based on simulation results).

References
Casadebaig P. et al., 2011. Agricultural Forest Meteorology 151, 163-178.
Casadebaig P. et al., 2016. European Journal of Agronomy 81, 92-105.
Casadebaig P. et al., 2022. Theoretical and Applied Genetics 135, 4049-4063
Chapman S.C., 2008. Euphytica 161, 195-208.
Jeuffroy M.H et al., 2014. Agronomy for Sustainable Development 34, 121-137
Wang E. et al., 2019. Journal of Experimental Botany 70, 2389-2401

Speaker: Philippe Debaeke (INRAE UMR AGIR)

Debaeke_oral_ESA_2024.pdf

9 Genetic x management interactions with solar radiation and temperature in the critical period to achieve high cereal and canola yields

Introduction
Australia is renowned for being a hot, dry and water limited crop production zone. However, parts of the Australian high rainfall zones (HRZ) have a growing season water supply that can in theory support yields greater than reported record yields globally. The physiological basis underpinning higher yields in these regions are relevant to a global audience aiming to raise the yield frontier. Potential yield benchmarking is an important and established method to assess yield gaps and productivity. The relationship between temperature and radiation in the critical period for yield formation, defined as the photothermal quotient (PTQ), has been demonstrated to be an accurate predictor of potential yield in wheat (Fischer, 1985; Rawson, 1987). However, the relationship between yield and PTQ in the critical period for barley and recently identified critical period for canola (Kirkegaard et al., 2018) has received less attention. In addition, these relationships have not been defined for new wheat cultivars, nor for novel farming systems such as spring sowing of barley (versus traditional autumn sowing), modern canola cultivars (hybrids) and the most recent crop management practices. Our objective was to compile data from high-yielding canola (> 5 t/ha) and cereal (>8t/ha) crops in Australian irrigated and HRZ crops to explore the relationship between temperature and radiation (PTQ) in the critical period on yield potential and determine which management practices influence growth in the critical period. We sought to determine the frequency with which PTQ was likely to limit yield relative to water and N supply under current management practices and to explore the relationship between PTQ and water supply on yield when other agronomic factors are not limiting. We focussed on the Australian HRZ (> 400 mm growing season rainfall), to make comparisons to other high production areas internationally in Europe, South America, and New Zealand.

Materials, Methods:
We compiled data from a series of cereal and canola agronomic experiments conducted across Australia’s HRZ from 2016 -2023. The data included phenology, biomass, yield and yield components as well as water and N supply, temperature, and radiation in the critical period. Relationships between PTQ in the critical period and yield were compared with simple and accessible seasonal potential yield calculators such as that developed by French and Schultz (1984) for water-limited yield, and more sophisticated daily timestep models such as APSIM (Holzworth et al., 2014).

Results:
Our extensive dataset reported yields greater than 6t/ha for canola and up to 17t/ha for wheat. These new insights revealed that the relationship between PTQ in the critical period and potential yield required updating for recent wheat cultivars and management. A modified equation could be used to provide a reliable estimate of barley and canola potential yield based on the highest yielding canola and barley crops in Australia’s high rainfall zone. These relationships held up well when expanded to commercial crops, including a record 7.2 t/ha canola in Oberon NSW, and cereals including world record crops reported in NZ and Europe approaching 18t/ha. In such high rainfall environments, the relationship between water supply and yield were less reliable determinants of yield potential. Highest yields came from a combination of higher biomass and higher harvest index suggesting the environmental drivers of these traits were favourable in the critical period.

Discussion
Our data reveals yield comparable to the highest recorded global yields are achievable in some parts of Australia, despite the national average well below other high production regions. Our data demonstrate that actual and yield potential > 6t/ha in canola, and >10t/ha in cereals, well above the national Australian average, are frequent and could be achieved in the HRZ with appropriate crop management to optimise the PTQ in the critical period. This provides a framework for improvement for growers, agronomists and breeders to re-consider temperature and radiation in the critical period as drivers of yield potential. A future focus for research could consider biomass accumulation and allocation during the critical period to improve yield further.

References:

Speaker: Kenton Porker (CSIRO)

115_Porker.pptx

10 Digital lean phenotyping methods in the context of wheat variety testing – the cases of canopy temperature and phenology

Plant phenotyping plays a crucial part in the development of new crop genotypes. In recent years, new digital phenotyping technologies have emerged, especially in the context of high throughput field phenotyping (Furbank and Tester, 2011). Many of these methods need expensive equipment or depend on stationary phenotyping platforms (e.g. Kirchgessner et al., 2016). Relatively simple and easy to use methods need to be developed if benefits of new digital technologies are to be transferred to daily use in variety testing or breeding. In this study, the applicability of relatively simple commercially available digital phenotyping devices was tested and improved in the context of wheat variety testing. Aerial thermography is used to evaluate the performance of genotypes by measuring canopy temperature (CT) as a low CT is indicative of the relative fitness of a plant to the environment (Reynolds et al., 2012). Because lightweight thermal cameras for drones are prone to significant thermal drift effects due to a lack of a signal stabilizing cooling (Wang et al., 2023), we propose a new approach to analyze drone based thermal images based on an image-wise method described in Roth et al. (2018). Through the inclusion of covariates such as trigger timing and the position of the drone relative to measured plots, temporal trends and viewing-geometry related effects could be mitigated, which improved the CT measurements. Correlations between measurements on 270 experimental wheat plots taken within 20 min were very strong (R = 0.99) and highly genotype specific with generalized heritabilities > 0.95 in many cases. In a second experiment, autonomous PhenoCams mounted on poles 12 m above the field were evaluated for their suitability to track later stages of phenology (BBCH) and senescence (% of senescence progression on leaf- and plant-level) as a replacement for time consuming manual field scorings. Senescence and maturity of wheat could be tracked reliably in the field for three subsequent seasons with strong correlations between field-scorings and image-based estimates (R > 0.8) in a 100-fold cross-validation of a PLSR-based model (Figure 1). For emergence, achieved correlations were poor. Both experiments demonstrated how image-based phenotyping with a simple and affordable setup can be used to derive high quality data relevant in the evaluation of the performance of wheat genotypes in the field.

Figure 1: Pearson correlation coefficients between manual field reference measurements and PhenCam based estimates of the timing of phenological stages (BBCH; BBCH values on the x axis), senescence on leaf level (SenLeaf; % of senescence on the x axis) and senescence on plant level (SenPlant; % of senescence on the x axis). The blue shaded area indicates the minimal, and maximal correlation achieved in a 100-fold cross validation based on a random 75%- 25% split into training and testing data. The blue line indicates the mean. Correlations when applying the whole dataset are shown in red.

References:
Furbank, R.T., Tester, M., 2011. Phenomics - technologies to relieve the phenotyping bottleneck. Trends in Plant Science 16, 635–644. https://doi.org/10.1016/j.tplants.2011.09.005

Kirchgessner, N., Liebisch, F., Kang, Y., Pfeifer, J., Friedli, M., Hund, A., Walter, A., 2016. The ETH field phenotyping platform FIP: A cable-suspended multi-sensor system. Functional Plant Biology 44, 154–168. https://doi.org/10.1071/FP16165

Reynolds, M.P., Pask, A.J.D., Mullan, D.M., 2012. Physiological breeding I: interdisciplinary approaches to improve crop adaptation. CIMMYT.

Roth, L., Aasen, H., Walter, A., Liebisch, F., 2018. Extracting leaf area index using viewing geometry effects—A new perspective on high-resolution unmanned aerial system photography. ISPRS Journal of Photogrammetry and Remote Sensing 141, 161–175. https://doi.org/10.1016/j.isprsjprs.2018.04.012

Wang, Z., Zhou, J., Ma, J., Wang, Y., Liu, S., Ding, L., Tang, W., Pakezhamu, N., Meng, L., 2023. Removing temperature drift and temporal variation in thermal infrared images of a UAV uncooled thermal infrared imager. ISPRS Journal of Photogrammetry and Remote Sensing 203, 392–411. https://doi.org/10.1016/j.isprsjprs.2023.08.011

Speaker: Treier Simon (Agroscope)

11 Modelling gene-based, trait-yield relationships in wheat to capture synergies from GxExM interactions

Wheat grain yield is strongly modulated by underlying genotype (G) by environment (E) and management (M) (GxExM) interactions. These interactions are difficult to interpret. Process-based crop modelling has the potential to disentangle the nature of GxExM interactions and assist in developing breeding and management synergies to increase crop performance for target environments. However, current crop models were developed using data collected from outdated cultivars and often assume uniformity of many important physiological traits (e.g. leaf size, tillering, resource use efficiency and partition of resources to different organs) across genotypes. Consequently, insights regarding the impact of elite traits of modern cultivars to optimise GxExM are limited.
Advances in trait genetics and digital field phenotyping have enabled large-scale data collection to quantify gene-trait linkages. Incorporating such data with established trait physiological models allows simulations of gene-trait-yield relationships across environments to develop value propositions for elite traits (or wheat lines) across a wide range of geographical regions in current and future climates. Further, the models have significant potential to assist breeding as they facilitate the evaluation of elite traits arising from, and knowledge underpinning targeted breeding efforts to enhance genetic yield potential.
We present recent model development for simulation of grain yield of novel wheat genotypes with the new genetic traits of early vigour and long coleoptiles. Our results revealed that these novel genotypes, coupled with deep sowing, could increase national wheat yields by 18–20% under historical climate (1901–2020) in Australia, with benefits also under future warming. We demonstrate how incorporation of genetic understanding and data into farming systems modelling can enable gene-trait-yield simulations across environments to assist in the design of ideotypes and management strategies to optimise GxExM for increased productivity and resilience of wheat under climate change.

Speaker: Enli Wang (CSIRO)

12 Leveraging plant variety trials for parameterization of DSSAT wheat models in Germany

Introduction

Cropping system models (CSMs) are vital tools in agricultural research, typically designed for plot level assessments but increasingly applied across different scales, aiding in understanding how crops respond to various factors like climate change (Asseng et al., 2013). However, when these models are scaled up, they face challenges due to limited data availability for parameterization (Angulo et al., 2013). Researchers use preset coefficients from model developers or previous studies, which can introduce uncertainties into the model-based assessments and respective outputs. It's crucial to accurately parameterize these models to tackle this issue, especially when exploring new locations or crop varieties. One promising approach is utilizing data from crop variety trials to fine-tune the models, ensuring they accurately reflect real-world conditions (Liang et al., 2021). In addition, one needs to consider that even with careful calibration, there is still inherent uncertainty related to model structure (Wallach et al., 2017). By employing a multi-model approach, researchers can minimize these uncertainties and improve the robustness of their predictions (Röll et al., 2021). Our study addresses these challenges by training three wheat models with a comprehensive dataset under German growth conditions, aiming to enhance yield predictions and optimize agricultural practices amidst changing environmental conditions.

Materials and Methods

In our study, we employed three wheat models from DSSAT: CSM-CERES, CSM-CROPSIM, and CSM-Nwheat. Ensuring consistent parameterization involved gathering cultivar-specific data from Germany’s Plant Variety Trials, supported by detailed growth data from a rain-out shelter trial in Braunschweig (52.296° N, 10.436° E; 75m a.s.l. (Schittenhelm et al., 2014). Soil data originated from the German Federal Institute for Geosciences and Natural Resources (BGR), and daily weather data from the German Weather Service (DWD), at a 1×1 km grid resolution. Model application encompassed four pedoclimatically contrasting sites across Germany: Feldkirchen (southeast, with good soil and high rainfall), Bad Lauchstädt (central, with good soil but limited rainfall), Thyrow (northeast, with poor soil and limited rainfall), and Gudendorf (north, with poor soil but high rainfall). We used the three models to simulate Management × Environment interactions in wheat production covering a span of 30 years (1991-2020). We evaluated the effects of six nitrogen treatments (0, 60, 120, 150, 180, and 200 kg Nitrogen per hectare) under rainfed vs. irrigated conditions considering productivity, efficiency and environmental impact of wheat production.

**

Results and discussion

**
Our study highlights the effective parameterization of DSSAT-CSM-CERES, DSSAT-CSM-CROPSIM, and DSSAT-CSM-Nwheat using plant variety trial data from diverse locations and cropping seasons nationwide. Using the same dataset, we achieved reasonable accuracy in predicting phenology, while for grain yield prediction, CSM-CERES exhibited an RMSE of 1405 kg ha-1, CSM-CROPSIM 2126 kg ha-1, and CSM-Nwheat 1886 kg ha-1.The distribution of simulated yield compared to observed yield (Figure 1) indicates close alignment, confirming model accuracy. Irrigation consistently increased yields in Bad Lauchstädt and Thyrow across all nitrogen levels, while no significant effects were observed in Feldkirchen and Gudendorf, suggesting sufficient rainfall for optimal plant growth under rainfed conditions. The CSM-CERES model exhibited higher yields at higher nitrogen levels (150N, 180N, 200N) across all locations, while CSM-CROPSIM and CSM-Nwheat showed similar effects in fewer locations. In conclusion, our study underscores the importance of robust model parameterization using diverse datasets, informing agricultural policy and climate change adaptation strategies nationally.

**

References

**

1. Asseng, Senthold, et al. "Uncertainty in simulating wheat yields
   under climate change." Nature climate change 3.9 (2013): 827-832.
2. Angulo, Carlos, et al. "Characteristic ‘fingerprints’ of crop model
   responses to weather input data at different spatial resolutions."
   European Journal of Agronomy 49 (2013): 104-114.
3. Liang, Xi, et al. "Deriving genetic coefficients from variety trials
   to determine sorghum hybrid performance using the CSM–CERES–Sorghum
   model." Agronomy Journal 113.3 (2021): 2591-2606.
4. Wallach, Daniel, et al. "Estimating uncertainty in crop model
   predictions: Current situation and future prospects." European
   Journal of Agronomy 88 (2017): A1-A7.
5. Röll, Georg, et al. "Implementation of an automatic time‐series
   calibration method for the DSSAT wheat models to enhance multi‐model
   approaches." Agronomy Journal 112.5 (2020): 3891-3912.
6. Schittenhelm, Siegfried et al. "Performance of winter cereals grown
   on field-stored soil moisture only." European Journal of Agronomy 52
   (2014): 247-258.

Speaker: Ashifur Rahman Shawon (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment)

13 Breeding progress in terms of carbon footprint reduction for five cereal crops in Germany

Abstract
Introduction:
This study employs a comprehensive Life Cycle Assessment (LCA) to examine the impact of breeding on yield, greenhouse gas emissions, and carbon footprint trends for five cereal crops (winter wheat, rye, winter barley, spring barley, and winter triticale) over a 39-year period.
Materials and Methods:
We utilized data from Variety for Cultivation and Use (VCU) trials, analyzing it through mixed model analysis. This method allowed us to differentiate genetic influences from non-genetic agronomic factors.
Results:
Our results indicate a significant, consistent genetic improvement in yields across all crops, particularly in winter triticale. However, yields plateaued around the year 2000 and subsequently declined, likely due to agronomic impacts from climate change, with rye being the most affected. The analysis of greenhouse gas emissions followed a similar pattern (Figure 1). Notably, the carbon footprint analysis showed a reduction due to genetic improvements, pointing to successful breeding for sustainability.

Figure 1: Five cereal crops’ genetic and non-genetic yield trend from 1960 to 2021
Discussion:
The findings underscore the dual role of breeding in enhancing crop yields and mitigating climate change effects. Despite genetic gains, non-genetic factors such as external environmental pressures pose ongoing challenges. The study highlights the critical need for breeding strategies that address these factors to sustain food production and contribute to environmental conservation.

Speaker: Donghui Ma (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment)

282_Ma.pptx

Innovative fertilizers and amendments for preserving crucial resources for agriculture

Conveners: Antonio Delgado, Maddi Malatsetxebarria

14 Impact of saline water Irrigation and biostimulant use on growth and phytocannabinoid profiles in fiber hemp (Cannabis sativa L.)

1. INTRODUCTION
Soil salinity affects more than 935 million hectares globally, especially in arid and semi-arid areas, and represents over 20% of the world's irrigated territories. Intensified by climate change — through higher evaporation rates, changes in precipitation, and sea-level rise — and human activities such as the overuse of fertilizers and unsuitable farming techniques, soil salinity presents a substantial challenge to both the environment and agriculture (Elmeknassi et al., 2022).
The increasing issue of saline soils, leading to challenges such as drought stress, ion toxicity, and hormonal imbalances, highlights the need for salt-tolerant crop systems (Akram et al., 2021). Salinity affects crops differently, depending on exposure duration, salt type, and genetic factors. Fiber hemp, with its adaptability to morphological, anatomical, and physiological changes under salt stress, including alterations in xylem vessel lumen (Guerriero et al., 2017), stands out as a viable option. Soil salinity's effect on enhancing secondary metabolites like essential oils and carotenoids (Bernstein et al., 2010) further underscores hemp's versatility. Its capacity to produce varied industrial products from different parts, despite saline conditions, suggests hemp as a sustainable solution for salt-impacted agricultural regions.

2. MATERIALS AND METHODS
The present study examines the effects of saline irrigation on hemp, utilizing NaCl solutions with electrical conductivities (EC) of 2.0, 4.0, and 6.0 dS m-1 (S1, S2, and S3, respectively), against a tap water control (S0). Furthermore, it explores the efficacy of a plant-based biostimulant, specifically a legume protein hydrolysate, in counteracting the adverse impacts of saline irrigation on both crop growth and its phytocannabinoid profile.

3. RESLUTS AND DISCUSSION
Water salinity and biostimulant application significantly impacted on the growth parameters of hemp, without notable interaction between these factors. Freshwater (S0) and low salinity (S1) treatments produced similar biomass yields, averaging 12.6 Mg DW ha-1, aligning with results from other studies (Struik et al., 2000). The highest salinity level (S3) significantly reduced total biomass by nearly half across all plant parts, while moderate salinity (S2) also led to decreased growth, especially in total and leaf biomass. Biostimulants application significantly boosted hemp growth, with total biomass, stems, leaves, and inflorescences increasing by up to 50%, even under salinity stress. Despite the reduction in crop growth by 7%, 30%, and 48% across S1, S2, and S3 salinity treatments respectively, biostimulant application mitigated the adverse effects of salinity, including potential toxicity and nutrient imbalances. Importantly, our analysis reveals that hemp demonstrates a medium-low tolerance to salinity, with less sensitivity to higher EC levels compared to other fiber crops like flax according to data reported in FAO Paper 29.
Collected data unveil the influence of salinity on Cannabis sativa's phytocannabinoid spectrum, with a notable increase in CBD levels under higher salinity conditions and a decrease in other cannabinoids like Δ9-THC. Through PCA and ASCA analyses, it is clear that sample origin and salinity levels significantly shape phytocannabinoid profiles, without any significant interaction among the variables considered.
Our study sheds light on hemp's adaptability to salinity, suggesting that tailored cannabinoid profiling and management strategies can refine hemp varieties for designated uses, from industrial to medicinal. In addition it emphasizes the significance of biostimulants in reinforcing plant resilience and yield.

4. REFERENCES
Akram, N. A., Shafiq, F., Ashraf, M., Iqbal, M., and Ahmad, P. (2021). Advances in salt tolerance of some major fiber crops through classical and advanced biotechnological tools: A Review. J. Plant Growth Regu. 40, 891–905.

Bernstein, N., Gorelick, J., and Koch, S. (2019). Interplay between chemistry and morphology in medical cannabis (Cannabis sativa L.). Ind. Crops Prod. 129, 185–194.

Guerriero, G., Behr, M., Hausman, J. F., and Legay, S. (2017). Textile hemp vs. salinity: Insights from a targeted gene expression analysis. Genes 8, 242.

Elmeknassi, M., Elghali, A., Pereira de Carvalho, H. W., Laamrani, A., and Benzaazoua, M. (2024). A review of organic and inorganic amendments to treat saline-sodic soils: Emphasis on waste valorization for a circular economy approach. Sci. Tot. Environ, 921, 171087.

Struik, P. C., Amaducci, S., Bullard, M. J., Stutterheim, N. C., Venturi, G., and Cromack, H. T. H. (2000). Agronomy of fiber hemp (Cannabis sativa L.) in Europe. Ind. Crops Prod. 11, 107–118.

Speaker: Nunzio Fiorentino (University of Naples, Department of Agricultural Sciences)

15 From soil to yield: unraveling the role of microbiome diagnostics in enhancing biofertilizer efficiency

Introduction
Excess use of mineral fertilizers can lead to eutrophication of rivers and lakes and biodiversity loss. Alternatives include the use of biofertilizers such as arbuscular mycorrhizal fungi (AMF). AMF form a symbiosis with most plant species, where they contribute to plant growth by providing essential nutrients such as phosphorus. However, the success of AMF inoculation is context dependent. To tackle this variability, we propose the development of microbiome diagnostics to predict successful inoculation with biofertilizer.
Materials, methods
We conducted 54 field trials in Northern Switzerland where maize was inoculated with Rhizoglomus irregulare SAF22. We calculated the mycorrhizal growth response (MGR) which is the percent change in biomass of inoculated plots compared to control plot. Soil properties were analyzed using classical chemical and physical parameters. The soil fungal community was characterized by long-read sequencing. AMF root colonization was assessed by microscopy. The root AMF community was sequenced with primers amplifying preferentially mycorrhiza. We used various statistical methods to predict the MGR based on the soil parameters and the soil microbiome.
Results and Discussion
In one quarter of the fields, inoculation with AMF increased yield significantly (Figure 1). Surprisingly, the degree of mycorrhizal growth response did not depend on mycorrhizal root colonization, whether assessed by either classical microscopy approach or by sequencing of the root microbiome. Soil parameters alone proved insufficient in explaining the response variability. However, integrating soil parameters with the soil microbiome resulted in a model that could explain up most of the variation in plant growth response. Furthermore, our investigation of the root microbiome unveiled intriguing dynamics. In most fields, the inoculated AMF led to a reduction in the abundance of native AMF. Moreover, in fields with high mycorrhizal growth response, the introduced strain decreased the abundance of several pathogenic strains, suggesting a possible mechanism whereby the introduced AMF effectively outcompetes root-associated plant pathogens, leading to enhanced maize plant growth. Overall, our study underscores the utility of soil fungal indicators as strong predictors of inoculation success.
References
Lutz, S., Bodenhausen, N., Hess, J., Valzano-Held, A., Waelchli, J., Deslandes-Hérold, G., Schlaeppi, K. & van der Heijden, M. G. (2023). Soil microbiome indicators can predict crop growth response to large-scale inoculation with arbuscular mycorrhizal fungi. Nature microbiology, 8(12), 2277-2289.
Figure caption
Mycorrhizal growth response (MGR) varied from −12 to +40%. Plot shows mean values (circle), as well as the confidence interval of MGR for each field (n = 8 independent plots), colors show year of experiment. Significant differences are highlighted by filled circles.

Speaker: Natacha Bodenhausen (Department of Soil Sciences, Research Institute of Organic Agriculture FiBL)

16 Human urine precipitates as a phosphorus source for lettuce in hydroponics for long-term crewed space missions

Soilless cultivation of plants during long-term crewed space missions will be essential to produce vital supplies such as clean water, food, and oxygen while sequestering atmospheric CO2. Fertilizer replenishment during these missions will be cost-prohibitive, so nutrients will need to be recycled from waste. Human urine is being explored as a source of nitrogen and phosphorus for plants, as it contains high concentrations of both. During urine storage, its urea gets hydrolyzed, which increases the pH and triggers the precipitation of circa 30% of the phosphorus contained in the urine. No study has yet offered a thorough analysis of the speciation of this precipitated phosphorus, nor of its solubility for use as a nutrient source for plants in hydroponics.

Our research investigates precipitates issued from stored human urine and from treated human and synthetic urine. We report the complete phosphorus speciation of the urine precipitates, using X-ray diffraction, Fourier-transformed infrared, and solid-state nuclear magnetic resonance spectroscopies. We also address the extractability of phosphorus from urine precipitates using anion exchange membranes and nutrient solution at pH≈6 as predictors of phosphorus availability for plant uptake. Finally, we assess the availability of phosphorus from urine precipitates to hydroponically grown lettuce.

We found that urine precipitates are predominantly composed of well-crystallized struvite ((NH4)MgPO4·6H2O), as well as of kovdorskite (Mg2PO4·3H2O), and amorphous calcium phosphate (Ca3(PO4)2ˑxH2O). Circa 70% of the phosphorus contained in the urine precipitates was extractable for plant nutrition, most of it derived from magnesium phosphate minerals. Plant experiments are underway aiming to confirm that this 70% of extractable phosphorus contained in the precipitates is available to lettuce grown in hydroponics.

To conclude, our research offers a valuable approach to nutrient recovery in space or any closed system, while improving the current understanding of waste recycling for terrestrial crop production.

Speaker: Icíar Giménez de Azcárate Bordóns

329_Giménez de Azcárate Bordóns.pptx

17 Effect of bio-based phosphorus fertilization on biofortification and root architecture of durum wheat in a rainfed agrosystem under mediterranean climate

1.Introduction
The future scarcity of phosphoric rock stocks is forcing to nutrient recycling at a societal scale by producing the so-called bio-based fertilizers (BBFs), allowing phosphorus (P) recovery and reuse in crop production. However, BBFs present a huge variability because they are produced from a wide range of agro-industrial by-products and different nutrient recovery techniques (e.g. composting, digestate, incineration, P-precipitation). P fertilization considerably affects not only P nutrition and crop yields, but also certain micronutrients bioavailability, such as Zinc (Zn) or Iron (Fe). These elements are essential for crops and, in addition, necessary in human diets. Low dietary intake in human diets produces many health problems, known as "hidden hunger". P fertilization also affects root architecture traits, influencing accessibility to soil nutrients and, consequently, crop performance and quality.

2.Materials, methods

In order to study how different P-BBFs affect crop micronutrient uptake and soil exploration (root architecture), a rainfed field experiment was conducted using 11 different BBFs to evaluate the effect on root development, micronutrient availability to crop, and grain biofortification in durum wheat (Triticum durum), particularly sensitive to Zn deficiency in calcareous soils. The molar ratio of P to micronutrients was also studied since it determines the digestibility of these micronutrients. The effect of BBFs was compared with commercial mineral P fertilizer (superphosphate) applied at the same rate.

3.Results and discussion

Limited yields were produced due to thermal stress and water scarcity during the trial. Despite not all BBFs performed equally, most BBFs increased Fe and Cu concentration while no significant differences were observed in Zn or Mn concentration in wheat grain. The molar ratio in wheat grain was also significantly affected by the P source, in particular the P: Fe ratio. This ratio was not affected by commercial mineral P supply but BBFs affected differently ranging from an increase of P Fe ratio with a variation of 24% to -50% when compared with non-fertilized control. BBFs obtained from sewage sludge ashes and poultry manure fertilizer presented the best performance in increasing micronutrient uptake and biofortification of Fe, Cu, Mn, and Zn. However, some organic BBFs with low P concentration (such as olive husk compost, or vermicompost) produced a negative effect on Fe concentration, probably due to sorption processes to organic matter that reduced its bioavailability under water deficiency. Higher root biomass was found in the BBF treatments that presented higher biofortification (sewage sludge ashes and poultry manure fertilizer), presenting up to a 22% increment of root biomass compared to non-fertilized control. A higher specific length express of roots was found in organic BBF treatments such as olive husk compost or plant digestates In this case, a lower nutrient bioavailability of organic BBFs would have produced an increase in root exploration of soil, which could make plants more resilient under water and nutrient scarcity conditions. Present results evidence the ability of BBFs to increase grain yield quality and modification of root development and morphology. However, variability among BBFs should be considered.

Funding: This work was funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 818309 (LEX4BIO). The results reported in this paper reflect only the authors’ views, and the European Commission is not responsible for any use that may be made of the information it contains.

Speaker: Mr Juan Nieto Cantero (Department of Agronomy, University of Seville, Spain)

18 Improving the bread making quality of winter wheat on organic farms using biogas digestate as a nitrogen fertiliser

Organic winter wheat is characterised by variable grain yield and quality. To bridge the yield and quality gap while minimising the potential environmental impact, nitrogen management needs to be improved. The aim of the study was to examine how organic farmers can achieve the bread making quality of winter wheat by modifying their management practices. A one season field study was con ducted on organic farms to understand the response of winter wheat grain yield and protein content to biogas digestate fertilisation depending on field properties and historical management. On-farm trials were set up on ten organic farmers’ fields in Västra Götaland County in southwest Sweden.
In 2021, the selected fields had a grass-clover ley, which was ploughed before winter wheat was planted in the autumn of 2021. The trials had a randomised block design with four replications, including three in cremental N rates from split doses of biogas digestate (60, 120, 180 kg N ha-1), and one unfertilised control treatment (N0). In addition to winter wheat grain yield and protein content, soil nitrogen supply (SNS) and general soil characteristics were also determined. To understand the variability across fields, information about the ley pre-crop was also recorded. Farmer fertilisation practices were investigated and compared to biogas digestate application.
The results showed that the application of biogas digestate significantly increased grain yield and protein content at all application rates. In contrast, in the unfertilised plots (N0) the grain yield was positively correlated to SNS, which ranged between 40-130 kg ha-1, whereas there was no signif icant relation to the grain protein content. When looking at individual fields, only a few farms were able to reach the optimum yield with the biogas digestate rates applied in the trials, i.e. the wheat crop could have responded further to a higher N-rate. The same pattern was observed for the grain protein content, where four out of ten trials gave a sufficient protein content (11.5%) to get the price premia for organic wheat, showing the po tential for targeted nitrogen management depending on site characteristics. The variation in field properties between the farms was mainly related to clay content, total soil carbon and mineral soil nitrogen concentration in the autumn, and total weed biomass. The nitrogen management practices that the farmers applied differed from field to field, with variations in choice of N source and N amount. As a result, the winter wheat yield between farms varied, with a six-fold increase from 2 to 12 tons ha-1, as did the protein content, from 8 to 14%. Results from the farmer practice plots did not reflect those obtained when applying similar amounts of N in the form of biogas digestate.
This study demonstrated how the bread making quality of organic winter wheat can be improved using grass-clover ley as a pre-crop in combination with biogas digestate application. The grain yield
was also dependent on the long-term build-up of soil fertility, which was affected by the soil nitrogen supply measured in the unfertilised plots.
Our findings raise the need to further investigate the potential
of alternative soil amendments and nutrient sources, potentially suitable for organic certification, and how they can contribute to the circular economy and sustainable nutrient management in organic farming systems.

Speaker: Rafaelle Reumaux (Swedish University of Agricultural Sciences (SLU))

Sustainable increase of productivity

Conveners: Bruno Rapidel, Daniel Marusig

19 How can models contribute to the design of cropping systems that meet both farmers' short-term problems and long-term objectives for sustainable weed management?

Introduction
Weeds are the most harmful pest among those targeted by pesticides for arable crops but they are also are beneficial (e.g. feeding wild fauna). If herbicides are the most effective to control them, their consequences on health and environment compel to reduce their use. To achieve this goal, farmers need to combine several partially effective techniques. While the effects of each technique are known, it is much more difficult (if not impossible) to predict short-term and long-term effects of their combination. During the COPRAA project, we demonstrated in different farmer groups that providing them with specific knowledge inputs and model results, is an effective way of motivating them and helping them in the design process, as it enables them to take both time scales into account.

Material and methods
Three workshops were held in each group of farmers, over a period of a few months: presentation of our method and definition of weed issues for at least one farmer; design of an innovative cropping system by the other members; discussion about the results of our assessment. The performances of each cropping system for weed management were assessed with the virtual field FLORSYS (Colbach et al., 2021), a mechanistic model simulating crop and weeds development and competition for light and nitrogen. DEXiPM (Pelzer et al., 2012) was used to assess the sustainability of the designed cropping systems.

Evaluation results for co-designed systems
The assessment of several innovative cropping systems with FLORSYS has pointed out three main trends (see one example in Table 1):
1. Although weed harmfulness for crop production increased a little in most of innovative systems, it remained low.
2. These performances are achieved while reducing significantly or even stopping herbicide use.
3. Mixed effects are observed on weed contribution to biodiversity: increase in food offer for wild fauna, but a decrease in weed species richness and/or evenness.

Results of discussions with farmers
Reducing or stopping the use of herbicides without increasing weed harmfulness implies multiple and significant changes in the cropping system, which may have consequences for its sustainability. We have submitted to the farmers the results of the multicriteria assessment (economic, social and environmental sustainability) performed with DEXIPM. These results have raised discussion on important subjects for farmers, such as the effect of tillage (especially ploughing) on soil fertility, the need to purchase new machinery, the technical know-how and outlets for new crops... The workshops with the farmer groups were also an opportunity to discuss about their perception of weed infestation in their fields and its long-term impact for the cropping system management. In our example, these discussions led to modifications of the succession of crops in the innovative system (column “Innovative system (2nd version)” in Table 1).

Conclusion
Mechanistic models, such as FLORSYS, are useful to answer questions of farmers or advisors when they design cropping systems in order to solve weed management issues. However, such models are complex to use, require a lot of input data and the length of simulations is not compatible with the duration of a workshop with farmers. That is why a simpler tool, DECIFLORSYS based on meta-modelisation, has been designed and completed during the project. Il will allow advisors to compute results for a cropping systems assessment in a few minutes.
Moreover, we carried out similar approaches in other groups with different production contexts and group composition (with or without advisors). The diversity of situations will make it possible to create a guide for the design of innovative systems aimed at sustainable weed management, specifying how the models can be used in the process.

Table 1: Performances of the current and innovative systems of a farmer in terms of weed management. There is no use of herbicides in the innovative systems (organic farming). Indicators are an average over total length of simulation (30 years) and are normalized: 1 is the best performance (green), 0 the worst one (red).

References
Colbach et al., 2021. The FLORSYS crop-weed canopy model, a tool to investigate and promote agroecological weed management. Field Crops Res. 261, 108006. https://doi.org/10.1016/j.fcr.2020.108006

Pelzer et al., 2012. Assessing innovative cropping systems with DEXiPM, a qualitative multi-criteria assessment tool derived from DEXi. Ecological Indicators, 18, 171-182. Doi: 10.1016/j.ecolind.2011.11.019

Speaker: Nicolas Cavan (INRAE Agroécologie, Dijon)

20 A multi-criteria tool for jointly assessing the sustainability and resilience of dairy farms

1. Introduction
   Livestock farms are a major contributor to environmental impacts [1]. For dairy farms, one strategy for reducing these impacts is to increase the share of grass in the animals' diet [2]. However, this increases their dependence on grass growth, and therefore on the climate, in the context of climate change. This raises questions about the possibility of reconciling sustainability and resilience for these farms.
   The aim of this study was to create and apply a tool for jointly assessing the sustainability and resilience of dairy farms.

2. Materials, methods
   The study was conducted in collaboration with a group of farmers and advisers promoting the use of grass in dairy farms (CEDAPA). A literature review and participatory workshops involving scientists and farmers were employed to create a conceptual framework on sustainability and resilience concepts. This framework was then transformed into a tool comprising criteria and indicators, validated by the stakeholders; the tool was implemented using the DEX method [3].
   The tool was then applied to 23 CEDAPA dairy farms. The determinants of sustainability and resilience were analysed by principal component analysis and hierarchical clustering using the tool's indicators as input variables (R software, version 4.2.2). The resulting determinants were associated with technical and economic descriptors of the farms.

3. Results
   Creation of the tool
   During workshops, tensions were identified between the two concepts, e.g. in terms of context and hypothesis: sustainability is assessed when the farm is in steady state whereas resilience is assessed when the farm faces changes. However, each concept was well-associated with a set of system properties, e.g. productivity or autonomy for sustainability and buffer capacity for resilience, represented in the conceptual framework. It allowed the creation of a tool that assesses whether dairy farms achieve the sustainability objectives and to what extent they can be maintained when facing disturbances. The tool was organised on six properties of sustainable and resilient farms (Figure 1), described by 37 indicators. The tool enables the classification of farms into five classes, ranging from those exhibiting very low resilience and sustainability to those demonstrating high resilience and sustainability.

Assessment of dairy farms with the tool
Fifteen farms were sorted in the two most sustainable and resilient classes, five farms in the intermediate class, three farms in the two least sustainable and resilient classes. An analysis of the determinants of the sustainability and resilience three clusters. Cluster 1 (eight farms) gathered organic, economically and environmentally efficient farms, all specialised in dairy production, with grass-based forage system. Ten of the eleven farms in cluster 2 were conventional, economically efficient, but not particularly environmentally effective. They were the most productive of the total set, used more maize and had a greater degree of diversification in sales than cluster 1. Cluster 3 comprised four organic farms, with moderate economic efficiency but good environmental performances. Their production strategy was grass-fed milk production and diversified sales.
In each cluster, at least two farms were in the most favourable class and the other were spread across two or four classes. This indicates that the three identified production strategies were capable of achieving satisfactory levels of sustainability and resilience.

1. Discussion
   The farms assessed demonstrated good performances in terms of sustainability and resilience. To be sure that the tool does not sort farms too easily into the most favourable classes, a Monte Carlo analysis was performed and showed that the most likely class is the least sustainable and resilient one.
   However, it is possible that the tool, constructed with CEDAPA criteria, favours their farming practices. To validate the tool, it is necessary to test it on a second set of farms. This will enable the tool to be evaluated in terms of its ability to discriminate between farms and farming systems.

2. References
   [1] Steinfeld, H., et al. (2006). Livestock ’s Long Shadow. FAO Collection: Environmental Issues and Options. FAO of the United Nations, Rome. p. 390.
   [2] Wezel, A., Peeters, A. (2014). Agroecology and herbivore farming systems–principles and practices. Options Méditerranéennes, 109, 753-768.
   [3] Bohanec, M., (2003) Decision support, in: Mladeniæ D., Lavraè N., Bohanec M., Moyle S. (Eds.), Data mining and decision support: Integration and collaboration, Kluwer Academic Publishers, 23–35.

Speaker: Julie Auberger (UMR SAS, INRAE)

A multi-criteria tool for jointly assessing the sustainability and resilience of dairy farms

21 Planning in uncertainty: vegetable producers and middlemen management of disturbances affecting production

In vegetable long value chains, products’ perishability requires to precisely plan production. Such planning has to respect middlemen (e.g., cooperatives or wholesalers) expectations: quantity and timing of supply. Besides farmers have constraints and objective including farm land, crop rotation, workload, and viable income. Middlemen agree with regular suppliers on a planned supply calendar, which is defined as coordinated and anticipated establishment of expected production (characterised by a crop, a volume and a timing). Planned supply calendar are defined several months in advance, before plantation, and are then usually adjusted depending on unexpected events (technical or commercial). However, in a context where disturbances become more frequent and intense, such routine adjustment may not be suited anymore. Our objective was to understand i) how farmers and middlemen usually adjust planned supply calendar to manage unexpected events, and ii) taking the example of drought, how major disturbances may challenge these routine adjustments. We then discuss how such short-term management leads to potential trade-offs with long-term goals.

Our method is inspired by the “diagnosis of uses”, which aims at understanding the diversity of ways to address an issue in a concrete situation of use (Cerf et al., 2012). We implemented a diagnosis of crop planning to understand how farmers and middlemen plan production, what disturbances they face and how they manage it (or not).
Our case study is located in the Roussillon plain (Pyrénées-Orientales, Southern France), a vegetable production basin mainly oriented towards long value chains, which underwent drought for the last two years. We conducted semi-structured interviews with 18 farmers, 6 middlemen and 2 advisors, following an iterative snowball sampling method. Quotes were inductively analysed to specify their topics.
One key step in planning process is seedlings ordering, as it implies to make non-reversible choice involving a significant amount of money (several thousand €/ha). Crop development is then monitored by middlemen in order to anticipate changes in planned supply calendar. During harvest, middlemen can manage overproduction at a given period by finding backup outlets (rather selling, even at low price than not selling). In case of shortage in planned supply, middlemen can solicit unplanned suppliers.
In a context of drought, interviewed farmers took different decisions, depending on farm resources, crops produced, and available information on water resource. Decisions taken included i) proceed regardless of risk, ii) cancel plantation or decrease planted area, iii) postpone plantation with hope that water will get available later, iv) prioritize crops already planted, and limit water use for non-productive soil management operations. Due to drought, middlemen face a risk of major supply shortage, which was managed by: i) buying a more important share of supply to unplanned suppliers located in another region not affected by drought, ii) one middleman committed to refund bought seedlings in case of a harvest loss, in order to encourage producers to take risk. The first strategy is a short-term disturbance management, and the second strategy seems to be emerging as a last resort measure, for cases where a crop central for middlemen cannot be sourced from other suppliers.

Farmers adaptations to disturbances such as drought aim to reduce economic impact, but in case all regular suppliers cancel or decrease production, this would lead to significantly reduced supply for middlemen. Thus, middlemen seek to secure their supply by broadening their supply basin or sharing risks taken by farmers. The short-term coping strategies we identified may however be implemented at the expense of longer-term goals in three ways. First, reduced production leads to reduced gross margin, for both farmers and middlemen, which may not be viable, particularly if drought is to last more than one or two years. Second, when farmers limit water uses for non-productive operations, this preserves gross margin on the short term, at the expense of longer-term production since such operations are important for soil quality management. Third, mutual trust built on long term between middlemen and regular suppliers cannot be built with unplanned suppliers solicited by middlemen for short-term disturbance management. Recurring solicitation of unplanned suppliers can also affect regular suppliers’ trust. Our results thus call for a broadening of perspective on long term, to anticipate potential intense and long-lasting disturbances.

References
Cerf et al., 2012. Agron Sustain Dev 42(4):4

Speakers: Axel Graner (INRAE), Laure Hossard (INRAE)

18thESA-Graner_VF.pdf

22 Improving soil quality while preserving farmers' income: An ecosystem services-centered conceptual framework

1. Introduction

There is an increasing need to improve soil quality (SQ) to preserve agricultural productivity and environmental benefits. While farmers can improve SQ by changing their production management (PM: set of farming practices), this can affect their farm income and therefore constitutes a challenge that can restrain them from improving SQ. To overcome this challenge, focusing on improving ecosystem services (ESs) rather than SQ itself offers both the potential to improve SQ and generate additional income as ESs can be marketed (e.g., payment for ESs). In this context, it is fundamental to clearly understand the consequences for farmers' income and SQ if farmers attempt to improve their ESs supply through PM. Several studies have approached part of the problem, and the most complete conceptual frameworks addressed the linkage between SQ, PM, and farm economics$^{1,2}$. However, studies that consider ESs at the center of the decision-making process are lacking, and/or poorly address the problem as a whole by considering each concept's complexity, and in particular the large diversity of ESs, SQ indicators, and farming practices. To fill this gap, we developed an ESs-centered conceptual framework that aims at providing a clear holistic qualitative understanding of the problem and a blueprint for further modeling/quantitative analysis. This framework was built with a focus on crop production systems and using an iterative process based on an extensive literature review and expert solicitation.

2. Conceptual framework

In Figure 1, the conceptual framework approach is presented and consists of setting the objective as “Improving ESs” while considering SQ, PM, and farm income as being directly and/or indirectly influenced by this objective. From this approach, it appears that “Improving ESs” results in a sequence of choices/requirements and consequences that create a combined effect on farm income. This sequence can be described with the following four relations: (1) “Improving ESs” requires changing PM, (2) changing PM directly influences SQ, (3) “Improving ESs” indirectly influences SQ through PM, (4) and finally “Improving ESs” (yield, and payments for ESs), PM (costs), and SQ (long term productivity) have a combined effect on farm income. Each relation was explored and described qualitatively (mostly in the form of tables and in terms of “positive”, “negative”, and “unclear/neutral” relations) using the most recent literature (mainly meta-analysis, and reviews). For this purpose, we used 19 ESs (food provisioning/yield, water quality, carbon sequestration, etc.), 50 farming practices (no-tillage, manure, cover crops, etc.), and 19 SQ indicators (incl. bulk density, pH, earthworm abundance, etc.) selected based on literature and expert solicitation. Finally, using this conceptual framework, the paper presents a blueprint for modeling and a semi-quantitative illustration.

3. Discussion and conclusion

Despite limitations including the lack of precise quantification, four major findings could already be drawn using this conceptual framework. First, it becomes obvious that decisions on ESs result in a sequence of choices and consequences that affect together farm income. Second, improving ESs leads to different trade-offs and synergies with SQ, depending on changes in PM required to improve ESs. For instance, while carbon sequestration can be improved by no-tillage and organic amendment, no-tillage tends to increase bulk density (at least in the short term) while organic amendment tends to decrease it. Third, synergies between ESs and SQ offer the potential to reduce the marginal costs of further improving SQ. Fourth, not only soil-related ESs but also non-soil-related ESs offer the potential to increase SQ while preserving income. For instance, pollination (a non-soil-related ES) could provide an additional income to enhance SQ, as pollination can be improved via agroforestry which can also positively influence several SQ indicators (e.g., water infiltration). In conclusion, the conceptual framework provides valuable qualitative insights and a blueprint for quantitative analysis, which will together contribute to the development of sustainable (people: ESs, planet: SQ, profit: farm income) farm business models.

4. References

1. Kik, M. C., Claassen, G. D. H., Meuwissen, M. P. M., Smit, A. B. & Saatkamp, H. W. The economic value of sustainable soil management in arable farming systems – A conceptual framework. Eur. J. Agron. 129, 126334 (2021).
2. Stevens, A. W. Review: The economics of soil health. Food Policy 80, 1–9 (2018).

Speaker: Mr Youssef Wang-Touri (Wageningen University & Research)

23 Use of past advisory bulletins to rebuild pest and disease historical annual pressures in French vineyards

1 Introduction
As a perennial crop, grapevine life history covers many decades, and the vines are exposed year after year to several biotic and abiotic hazards. The cumulative effect of such exposures influences the present health and productive potential of the vines. It is there important to understand the vine past in order to manage them properly.
The protection of crops against pests and diseases have always been a major concern for growers. To help them, advisory bulletins have been provided to growers under different forms for almost one century by the French service of Plant Protection, part of the Ministry of Agriculture. They constitute an important source of information on the history of biotic threats and crop protection.
The aim of this work was to reconstruct the vines’ past exposure to diseases and pests. We build time series of annual indicators of grapevine pests, using agricultural warning bulletins from several French wine-growing regions.
2 Materials and methods
2.1 Material used
The publication in France of warning bulletins, called “Avertissements Agricoles” (AA), began in the 1940s, although some other forms of advisory bulletins existed previously. The AAs were edited in each region for each crop. In 2009, they were replaced by the “Bulletin de Santé du Végétal” (BSV), that came in a uniformed format in all regions.
To rebuild the past exposure to pests and diseases, we collected long time series of these documents (at least 60 years) in three different wine-growing regions covering the whole range of climate variations in France. We collected periodical bulletins published along the seasons, and, as soon as possible, annual syntheses.
2.2 Document analyses
In each studied region, we selected the main grapevine pests and diseases and analyzed the information for each of them. We collected, in the yearly synthesis or periodic bulletins, all the words or parts of sentences describing the observed prevalence, on one hand, and the severity, on the other hand, of the pest. We then translated these textual elements into a severity and a prevalence score, and constructed an aggregated scale of these two scores to obtain a final annual score. Repeating these steps for each year allowed us to build time series of pest or disease level over the studied winegrowing region.
3 Results
We collected and analyzed advisory documents from the three French wine growing regions of Bordeaux, Champagne and South Rhône Valley / Vaucluse. The timespan covered by these corpus differs between regions: in Bordeaux, we succeeded in and calculating pests and diseases indicators from 1940, in Champagne from 1944 and in Vaucluse from 1954, with fewer gasps in time series after 1960.
The result of this work consisted in time series of annual pest levels. The level was expressed in a semi quantitative score ranging from 0 (absence) to 6 (pest or disease generally present over the region and with high severity). Grades 1 to 3 indicate local attacks, grades 4 to 6 indicate generalized presence of the pest over the region. The figure shows the calculated levels of powdery mildew in the three regions from 1961 on.
4 Discussion
This work allowed us to build and validate a method for translating textual information on past pest and disease levels into semi-quantitative scores, and to validate it in different regions. However we had to develop region-specific decision rules, mainly to account for the prevalence. We will now relate the obtained time series to climatic time series and have engaged collaborations with historians to rebuild the past socio-technical context of grapevine protection against pests and diseases. Apart from the need of local adaptation, the method for analyzing advisory documents can easily be transferred to other cultivated species and other pests and diseases mentioned in these documents.
5 References
https://archive.org/search.php?query=subject%3A%22Collection_Inra_Averstissements-Agricoles%22
Fermaud, M., Smits, N., Merot, A. Roudet, J., Thiery, D., Wery J. and Delbac, L. 2016. New multipest damage indicator to assess protection strategies in grapevine cropping systems. Aust. J. Grape Wine Res. 22: 450‑61.
Zwankhuizen, M. J., and Zadoks, J. C. 2002. Phytophthora infestans’s 10-Year Truce with Holland: A long-term analysis of potato late-blight epidemics in the Netherlands. Plant Pathol. 51: 413‑423.

Speakers: ANNE MEROT (INRAE, CIRAD, Institut Agro, UMR ABSys , Montpellier, France), Nathalie Smits (INRAE, CIRAD, Institut Agro, UMR ABSys , Montpellier, France)

24 Syppre, a unique experimental network to meet the sustainability objectives of agricultural systems

Agriculture must reconcile food production, energy production and conservation of the environment, while ensuring a fair income to farmers. This requires a shift towards new production systems, based on both ecological intensification and technical innovations, adapted to local conditions and usable by farmers. To address this issue, the French technical institutes on arable crops ARVALIS, Terres Inovia and Institut Technique de la Betterave (ITB), launched a collaborative project called Syppre in 2014 (Toqué et al., 2015). It consists of an experimental network of diversified cropping systems implemented in five locations that are representative of France’s major regions for arable crop production: the deap loamy soils of Picardie, the chalk soils of Champagne, the shallow clay-limestone soils of Berry, the clay-limestone hillsides of Lauragais and the humus-rich soils of Béarn. For each site, we have verified that the reference system is the dominant system of the representativeness area (Galano et al. 2024). On each experimental platform we experiment this reference cropping system and one or several innovative systems. The latter have been co-designed with local stakeholders to meet a multi-performance objective defined as follow: profitability and productivity higher than or equal to the reference, and improved environmental performance compared with the reference. They also aim to meet local challenges such as controlling certain weeds or reducing erosion. Environmental and input use performance is measured by indicators such as treatment frequency index (TFI), mineral nitrogen application, greenhouse gases emissions (GHG) emissions and soil organic matter content. Target thresholds have been set to be consistent with public policies: -50 % compared to regional reference for TFI, -20 % for GHG emission (SNBC, 2020).
The multi-criteria evaluation is carried out using the SYSTERRE tool (Casal et al. 2022). To meet the objectives, the innovative systems mobilize and combine several technical solutions based on a systemic approach, such as more diverse rotations including legumes, cover crops and reduced tillage wherever possible.
At the system level, environmental and input use performances reach the expected goal in average for the 7 years of trial, with a reduction in GHG emissions of over 20% compared to the reference system, less mineral nitrogen used, lower TFI on 4 of the 5 platforms, and a positive carbon balance. However, this has been achieved at the expense of economic performance: the profitability of innovative systems is lower than that of reference systems, due to the weight of diversification crops in rotations and their lower productivity (Longis et al. 2024) (see figure attached).
The presentation will detail the results of the innovative Syppre systems and question the cost of implementing agroecological levers for farmers at the exploitation scale. It will illustrate the difficulties encounter by experimentators to answer short term and long-term objectives, and the compromises they have to make each year.

CASAL L, BERRODIER M, JOUY L, WISSOCQ A, ROUILLON C. SYSTERRE: un outil d’évaluation de la multiperformance des systèmes de culture aux multiples usages. Phloème 2022.

GALANO et al. Landscape unit : a framework for discussing the representativeness of cropping system. Under soumission. 18th congress of ESA

LONGIS, et al, 2024. Performance of innovative cropping systems diversified with oilseeds and protein crops: identification and resolution of methodological issues, using the Syppre experimental network as a case study. Oilseeds & fats Crops and Lipids 31: 2

STRATEGIE NATIONALE BAS CARBONE - La transition écologique et solidaire vers la neutralité carbone - Ministère de la Transition Ecologique et Solidaire - Mars 2020 https://www.ecologie.gouv.fr/sites/default/files/2020-03-25_MTES_SNBC2.pdf

TOQUE C, CADOUX S, PIERSON, P, DUVAL R, TOUPET A-L, FLENET F, CARROUE B, ANGEVIN F, GATE P. 2015. SYPPRE : A project to promote innovations in arable crop production mobilizing farmers and stakeholders and including co-design, ex-ante evaluation and experimentation of multi-service farming systems matching with regional challenges. 5th International Symposium for Farming Systems Design.

Speaker: Marie Estienne

#184_Estienne.pdf

12:55 PM Lunch break

Uncovering rhizosphere microbial resilience and potential to support plant growth - Mika Tarkka

Convener: Philippe Hinsinger

ESA2024_keynote_Tarkka.pdf

25 Uncovering rhizosphere microbial resilience and potential to support plant growth

Speaker: Mika Tarkka (UFZ)

ESA2024_keynote_Tarkka.pdf

3:20 PM Coffee break

Poster session #1

Cropping systems changes to support agro-ecological transitions

Conveners: Anna Birgitte Milford, Solèmne Skorupinski

26 Improving relay intercropping of service crop in cereal systems to cope with climate change

Service crops into crop rotations may provide ecosystem services and reduce dependency to inputs. Its relay intercropping into a winter cereal allows better conditions for service crop emergence in spring, compared to summer sowing, with limited risks for crop productivity (Gardarin et al., 2022). Nevertheless, sowing the service crop into an established crop is constraining and may hinder its establishment as the provision of services (Vrignon-Brenas et al., 2016). The risk of failure, increased with climate change, is a serious impediment to the implementation of such practice. This work aims at evaluating options, based on farmers innovations, increasing success of relay intercropping of a legume service crop in cereal cropping systems.

The research program CASTOR (TERRA ISARA) consists first in interviewing inspiring farmers and expert having experience in relay intercropping of service crop. It permitted to identify the main lock-in farmers were facing but also the rationale for action innovative farmers developed to overcome some of them. Thereafter, on farm experiments were designed with volunteer farmers to test some of the identified techniques in different agricultural, soil and climate conditions. 16 experiments were implemented in 2 years, mainly focused on service crop implementation and services evaluation. 2 main factors were crossed: 1/ service crop species and 2/ sowing methods leading to 7 to 10 experimental plots per field. Sowing methods principles were common (1/ broadcast sowing (BS); 2/ BS + harrowing (BSH) and optional 3/ row seeding (RS) but the implementation was adapted to conditions and available machinery. Cash crop, service crop and weeds density, biomass and nitrogen content were monitored from service crop sowing to the next crop harvest. In the same period, soil water and nitrogen dynamics were monitored.

No significant impact on winter wheat yield or protein content was observed. Due to bad climate conditions, the mean emergence rate of service crops was low (~20%). In most cases (12/16 fields), sowing of red clover (cv. Lestris-RC) led to a faster and denser establishment (183pl/m² at wheat flowering) compared to white clover (cv. Melifer-WC-~108pl/m²)(p-value<0.01). WC also led to lower mean biomass production at wheat harvest (125kgDM/ha vs. 300kgDM/ha – p-value<0.01) and higher risk of failure (almost 50% of WC treatments presented no clover biomass vs. 30% for RC). The mixture of red (50%) and white (50%) clovers (MC) presented intermediate emergence and biomass production.
BS generally permitted low emergence of clovers, whatever the sown species. Subsequent harrowing (BSH) significantly improved this emergence. RS permitted to increase rate of emergence of RC but not WC. WC small seeds were not adapted to some seeders used, making very difficult to control WC sowing density. Yet, WC survival was significantly increased with RS (~25% with no biomass compared to 55% for BS treatments) but this does not lead to higher biomass production. RS only permitted to increase significantly (p<0.01) the MC biomass at wheat harvest to a level almost equivalent to RC treatments (~350kgDM/ha vs. ~400kgDM/ha).

White clover, considered less competitive for cash crop, is often implemented by farmers testing relay intercropping. However, competition with an already established winter cereal disqualifies this species in our conditions, as WC is too sensitive to radiation limitation (Frame, 2005), being less adapted to cereal competition. Broadcast seeding of service crop, largely used by farmers clearly underperforms but subsequent harrowing significantly improves the service crop establishment. Some interviewed farmers suggest RS as a way to strongly reduce sowing failure but others feared potential damage to the cereal. If no significant impact on cereal yield was measured, this technique may not be adapted to every condition (e.g. soil compaction). It is time consuming and the question of profitability of such technique has to be addressed in comparison with the broadcast seeding with harrowing technique. The machinery used strongly influences the result of the sowing (e.g. seeder not adapted to very small grains).

Frame, J., 2005. Forage Legumes For Temperate Grasslands. FAO.
Gardarin, A., Celette, F., et al. 2022. Intercropping with service crops provides multiple services in temperate arable systems: a review. Agron. Sustain. Dev. 42, 39. https://doi.org/10.1007/s13593-022-00771-x
Vrignon-Brenas, S., Celette, F., et al. 2016. Early assessment of ecological services provided by forage legumes in relay intercropping. Eur. J. Agron. 75, 89–98. https://doi.org/10.1016/j.eja.2016.01.011

Speaker: Florian Celette (ISARA)

27 Is rapeseed - service plants intercropping a solution to mitigate biotic stresses?

Introduction

Sowing winter oilseed rape (WOSR, Brassica napus subsp. napus) with other species has been promoted in Europe for the last 10 years. Various advantages were pointed, like enhanced nitrogen nutrition (Lorin et al., 2016), improved weed control (Lorin et al., 2015) and less insect pest pressure (Breitenmoser et al., 2022). However, in the practice, farmers face difficulties to implement this technique, among them the choice of species intercropped with WOSR or the adaptation of the cropping technique.

Herbicides and insecticides are the most common phytosanitary products used in WOSR, with sometimes several insecticide applications in autumn and in spring. The role of service plants intercropped with WOSR in reducing weed pressure and pest damages has been assessed in field experiments, and in a farmers’ fields network.

Material and Methods

In order to assess the sowing of service plants with WOSR in the practice, an agronomy diagnosis was performed on 28 farmer’s field in the seasons 2018-2019 and 2019-2020. Additionally, the role of the addition of faba bean as service plant with WOSR was investigated in a two-year field trial. The impact of insect pests (Psylliodes chrysocephala, Ceutorhynchus napi, and Brassicogethes aeneus) was monitored over each season according to the standard procedures (i.e. number of larvae per plant (Berlese extraction), number of oviposition punctures, and number of insects per plant, respectively).

Results and discussion

The impact of the intercropping on weeds depends on the choice of species. A comparison of services plants species mixtures showed that non-legumes were the most efficient to increase service plants biomass in autumn and therefore reduce weed infestation, even when included in the mixtures at a low density. However, they can also negatively impact WOSR yield due to a high competition for light and nitrogen. Legume service plants were less competitive with WOSR but due to their slow development, their beneficial effect on the system could be low if they don’t produce enough biomass.

Among legume species, faba bean combines several interesting traits. With a fast development compared to other legume tested as service plants, it could relatively well compete with weeds without resulting in WOSR yield reduction, as it fixes more nitrogen. In field trials, faba bean was shown to mitigate damage caused by the pest complex of Psylliodes chrysocephala, Ceutorhynchus napi, and Brassicogethes aeneus, while having a positive impact on WOSR grain yield. Subsequent observations confirmed the effect on the pest complex. The mechanism behind these results, direct effect through visual or olfactive disruption or indirect effect through WOSR development are under study.

Sowing WOSR with companion plants has the potential to significantly reduce the impact of weed and insect pests on the cash crop, provided this technique is well managed. However, in the case of high pressure, additional measures are needed to secure high grain yields. Along with other alternatives (e.g., cultivar selection, early sowing, trap strip), this approach could reduce the use of synthetic chemistry in WOSR while supporting crop yield and promoting in-crop biodiversity and functional trophic groups.

References

Breitenmoser, S., Steinger, T., Baux, A. & Hiltpold, I. (2022) Intercropping Winter Oilseed Rape (Brassica napus L.) Has the Potential to Lessen the Impact of the Insect Pest Complex. Agronomy 12
Lorin M, Jeuffroy MH, Butier A, Valantin-Morison M (2015) Undersowing winter oilseed rape with frost-sensitive legume living mulches to improve weed control. Eur. J. Agron. 71, 96-105.
Lorin M, Jeuffroy MH, Butier A, Valantin-Morison M (2016) Undersowing winter oilseed rape with frost-sensitive legume living mulch: consequences for cash crop nitrogen nutrition. Field Crops Res. 193, 24-33.

Speaker: Dr Alice Baux (Agroscope)

28 Maximizing tree diversity in cocoa agroforestry: taking advantage of planted, spontaneous, and remnant Trees

1. Introduction: Cocoa production is recognized as a main factor of forest loss and biodiversity declined in west Africa[3]. Thus, agroforestry is being promoted to restore a minimum forest cover, to conserve biodiversity, and to reinstate key ecosystem services in agricultural landscape. This introduced the Cocoa Forest Initiative in Ivory Coast and Ghana and several certifications for adequate forest cover in cocoa plantations while ensuring cocoa production[4]. Consequently, millions of trees are distributed in cocoa fields. However, it has largely failed, as very few trees have survived and developed properly[5]. Paradoxically, most forest tree species found in cocoa fields today are from natural regeneration, selected by farmers[5]. Three distinct cohorts of trees associated with cocoa plantations[5]: (1) trees spared during forest clearing (remnants), (2) transplanted or planted trees (planted), and (3) spontaneously recruited trees (spontaneous) after or during the creation of the cocoa plantation. The objective of this study is to understand the structure of tree diversity in Ivorian cocoa plantations and identify the main determinants.

2. Materials and Methods: Across 150 cocoa plots, we inventoried all trees with a diameter at breast height (DBH) ≥ 10 cm present on each plot. Twelve socio-environmental variables were measured/estimated for each plot.
   (1) We calculated the Shannon’s Alpha and Beta diversity for each cohort and each pair of cohorts respectively and then expressed them in Hill numbers. (2) We assessed the effects of twelve socio-environmental variables on the alpha diversity of each cohort with a log-normal likelihood model.

3. Results: Alpha diversity in these fields comes from spontaneous and remnant trees, while planted trees exhibit very low Alpha diversity. However, since planted trees show high complementarity (resulting in high Beta diversity) with spontaneous and remnant trees. Several socio-environmental factors explain these different levels of observed diversity. These factors exhibit different effects by cohort.
4. Discussion: Planted or transplanted trees are typically fruit trees[6], Occasionally, commercial timber species are found[5] explained the low diversity observe. The remnant trees which are spared to provide shade for young cocoa plants[4] reflect the level of diversity of the forest preceding the cocoa plantation, a level that is very high[7]. Spontaneous trees mainly come from propagules from remnant trees[1]. That explained the high diversity of remnants and spontaneous trees. Planted trees and remnant/spontaneous are very complementary and can be explained by the exotic or non-indigenous nature of many planted species, particularly fruit trees[6]. Planted, spontaneous and remnants trees have different ontogenetic development Consequently, it is expected that performance trajectories and the factors modulating these trajectories will be very different among cohorts[2].
5. References:

1.Amani, B. H. K., N’Guessan, A. E., Van der Meersch, V., Derroire, G., Piponiot, C., Elogne, A. G. M., Traoré, K., N’Dja, J. K., & Hérault, B. (2022). Lessons from a regional analysis of forest recovery trajectories in West Africa. Environmental Research Letters, 17(11). https://doi.org/10.1088/1748-9326/ac9b4f
2.Aubry-Kientz, M., Rossi, V., Boreux, J. J., & Hérault, B. (2015). A joint individual-based model coupling growth and mortality reveals that tree vigor is a key component of tropical forest dynamics. Ecology and Evolution, 5(12), 2457–2465. https://doi.org/10.1002/ece3.1532
3.Barima, Y. S. S., Kouakou, A. T. M., Bamba, I., Sangne, Y. C., Godron, M., Andrieu, J., & Bogaert, J. (2016). Cocoa crops are destroying the forest reserves of the classified forest of Haut-Sassandra (Ivory Coast). Global Ecology and Conservation, 8, 85–98. https://doi.org/10.1016/j.gecco.2016.08.009
4.Kemper, L., Sampson, G., Larrea, C., Schlatter, B., Luna, E., Dang, D., & Willer, H. (2023). The State of Sustainable Markets 2023: Statistics and Emerging Trends.
5.Kouassi, A. K., Zo-Bi, I. C., Aussenac, R., Kouamé, I. K., Dago, M. R., N’guessan, A. E., Jagoret, P., & Hérault, B. (2023). The great mistake of plantation programs in cocoa agroforests – Let’s bet on natural regeneration to sustainably provide timber wood. Trees, Forests and People, 12(February). https://doi.org/10.1016/j.tfp.2023.100386
6.Laird, S. A., Awung, G. L., & Lysinge, R. J. (2007). Cocoa farms in the Mount Cameroon region: Biological and cultural diversity in local livelihoods. Biodiversity and Conservation, 16(8), 2401–2427. https://doi.org/10.1007/s10531-007-9188-0
7.Maney, C., Sassen, M., & Hill, S. L. L. (2022). Modelling biodiversity responses to land use in areas of cocoa cultivation. Agriculture, Ecosystems and Environment, 324, 107712. https://doi.org/10.1016/j.agee.2021.107712

Speaker: Mr Kouamé Isaac Konan (University Felix Houphouet-Boigny)

29 Tracking-down inter-farm collaborations to promote crop diversity

Introduction
Crop-livestock integration and crop diversification are major levers for the development of agroecology and for improving farming system resilience by e.g. limiting disease pressure, optimizing the use of nutrients and regulating the water cycle (Lin, 2011; Martin et al., 2016). However, their implementation on the long term by farmers is a challenge, as they require an increased workload and more knowledge. Inter-farm collaborations involving the sharing of fields or a common crop planning, including pastures and crops to feed livestock, appear to be a lever for crop diversification. These organizations are poorly documented in the literature.
In this study, we aim to analyse how farmers collaborate to develop diversified production systems.
This study is part of a larger project conducted with Agrobio 35, i.e. the local organic farming syndicate, and a group of farmers that raised the topic of inter-farm collaboration to enhance crop diversification. This project aims at co-designing inter-farm collaborations with the group of farmers and produce transferable knowledge to provide advice to producers.

Materials and methods
To identify and analyse innovative inter-farm collaborations, we use the innovation tracking method (Salembier et al., 2021) organized in five steps:
1) Defining a tracking project
2) Unearthing on farm innovations
3) Getting to know innovations
4) Analysing learnings from the innovations
5) Generating agronomic content

We identified farmers through snowball sampling. We conducted the semi-structured interviews with the farmers involved in the collaboration separately, following these categories:
A) Farm presentation

B) Collaboration presentation

1. Type of collaboration (Who is involved? What is exchanged? What values are assigned and how are they assigned?)
2. Formalization of the collaboration

C) What leaded to this kind of collaboration?

1. Economic, social, geographical context
2. Motivation for collaborating with other farms
3. Major changes in collaboration
4. Perspectives

D) Externalities

1. Diversification
2. Benefits on soil, yield (quantity and quality), use of inputs, biodiversity
3. Agri-environmental, social and economic satisfaction.

The interviews were analysed with qualitative multi-theme coding (Ayache and Dumez, 2011) in an inductive approach. We estimated how inter-farm collaborations impact crop diversity on farms.

Results and discussion
First, we described how the collaborations work and how they are organized. We analysed the formalization between the farmers, the motivations and the development conditions of these innovations. Then, a cross-sectional analysis of the cases enabled us to identify similar groups or trends (e.g. type of farm influencing the type of collaboration, or formalization being influenced by the trajectory of the collaboration). Favourable contexts to set up collaborations, common ways of formalizing and difficulties often encountered are highlighted. We focussed on the direct or indirect impact of livestock (e.g. feed crops and pastures in the rotations, organic fertilisation) on the crop rotations, in the cases of crop-livestock integration at inter-farm level. We then discussed the impact of these collaborations on crop diversity.
This research contributes to a better understanding of inter-farm collaborations and provide references for stakeholders that can enhance innovation process (Salembier et al., 2021). The results will be shared with Agrobio 35 and the group of farmers of the project.

References
Ayache, M., Dumez, H., 2011. Le codage dans la recherche qualitative une nouvelle perspective ? 7.
Lin, B.B., 2011. Resilience in Agriculture through Crop Diversification: Adaptive Management for Environmental Change. BioScience 61, 183–193. https://doi.org/10.1525/bio.2011.61.3.4
Martin, G., Moraine, M., Ryschawy, J., Magne, M.-A., Asai, M., Sarthou, J.-P., Duru, M., Therond, O., 2016. Crop–livestock integration beyond the farm level: a review. Agron. Sustain. Dev. 36, 53. https://doi.org/10.1007/s13593-016-0390-x
Salembier, C., Segrestin, B., Weil, B., Jeuffroy, M.-H., Cadoux, S., Cros, C., Favrelière, E., Fontaine, L., Gimaret, M., Noilhan, C., Petit, A., Petit, M.-S., Porhiel, J.-Y., Sicard, H., Reau, R., Ronceux, A., Meynard, J.-M., 2021. A theoretical framework for tracking farmers’ innovations to support farming system design. Agron. Sustain. Dev. 41, 61. https://doi.org/10.1007/s13593-021-00713-z

Speakers: Antonin PEPIN (INRAE), Mrs Marthe MOSSET (INRAE)

254_Pépin.pptx

30 Contribution of diversification to resilience capacities of agricultural systems

1. Introduction:
   Agricultural systems are vulnerable to pressure from multiple drivers, i.e. today’s agricultural landscapes are neither sustainable in terms of long-lasting (Agovino et al. 2019), nor are farms resilient in terms of responsive to (external) pressures (Meuwissen et al. 2020) .
   Prevailing productivity-oriented management practices have led to structurally simplified landscapes, exacerbating the vulnerability to external pressure (Hermanns et al. 2017; Clough et al. 2020; García et al. 2020). To overcome the difficulties, which are linked to those simplified and intensified systems, there is a trend for diversification (Reckling et al. 2023; Beillouin et al. 2021) leading to changes and transformation of the agricultural system.
   We explored the potential of agricultural diversification at field, farm, and landscape levels for overcoming short-term shocks and long-term challenges. We addressed the three resilience capacities robustness, adaptation, and transformation. We investigated (i) whether diversification can contribute to sustainable landscapes and resilient farms, and (ii) whether a farm can achieve the three resilient capacities robustness, adaptation and transformation simultaneously or whether there are trade-offs among those.

2. Methods:
   Employing a slightly adapted resilience framework developed by Meuwissen et al. (2019), we took a participatory approach to analyse the contribution of diversification options on the three resilience capacities in three research areas in Brandenburg (Germany).

3. Results:
   Our results show that various agricultural diversification options exist, which mostly aim at one resilience capacity of the resilience framework. However, our analysis leads us to the conclusion that a system cannot simultaneously fulfil all three resilience capacities. It is imperative to consider the concept of the adaptive cycle, as described by Gunderson and Holling (2002), wherein a dynamic systems moves through the distinct phases of exploitation, conservation, release, and reorganization. This cyclical nature was particularly evident in our examination of transformation capacity. While a resilient system should always possess the ability to undergo transformation, the process of transformation needs up so many resources, that afterwards a period of pause is required. Unlike the gradual processes of robustness and adaptation, transformation represents a more abrupt and profound shift within a system.

4. Discussion:
   The findings underscore the interconnectedness of diversification initiatives and resilience dynamics within agricultural systems. While diversification in general enhances the resilience of agriculture, different forms of resilience aim at different resilient capacities. While robustness defines a stable system, adaptation describes incremental adjustments and responses to changing conditions over time. In contrast to that, transformation manifests as a sudden and significant restructuring or reorganization of the system after which a phase of stability needs to come, as the system needs to recalibrate. they alternate rather than taking place simultaneously. A system is only resilient if it can alternate between all three capacities over a long period of time.

5. References:
   Agovino, Massimiliano; Casaccia, Mariaconcetta; Ciommi, Mariateresa; Ferrara, Maria; Marchesano, Katia (2019): Agriculture, climate change and sustainability: The case of EU-28. In Ecological Indicators 105, pp. 525–543. DOI: 10.1016/j.ecolind.2018.04.064.
   Beillouin, D.; Ben-Ari, T.; Malézieux, E.; Seufert, V.; Makowski, D. (2021): Positive but variable effects of crop diversification on biodiversity and ecosystem services. In Global Change Biology 27 (19), pp. 4697–4710. DOI: 10.1111/gcb.15747.
   Clough, Yann; Kirchweger, Stefan; Kantelhardt, Jochen (2020): Field sizes and the future of farmland biodiversity in European landscapes. In Conservation letters 13 (6), e12752. DOI: 10.1111/conl.12752.
   García, Virginia Rodríguez; Gaspart, Frédéric; Kastner, Thomas; Meyfroidt, Patrick (2020): Agricultural intensification and land use change: assessing country-level induced intensification, land sparing and rebound effect. In Environ. Res. Lett. 15 (8), p. 85007. DOI: 10.1088/1748-9326/ab8b14.
   Gunderson, L. H., & Holling, C. S. (2002). Panarchy: Understanding transformations in human and natural systems. Island press.
   Hermanns, Till; Helming, Katharina; König, Hannes J.; Schmidt, Katharina; Li, Qirui; Faust, Heiko (2017): Sustainability impact assessment of peatland-use scenarios: Confronting land use supply with demand. In Ecosystem Services 26, pp. 365–376. DOI: 10.1016/j.ecoser.2017.02.002.
   Meuwissen, Miranda P.M.; Feindt, Peter H.; Midmore, Peter; Wauters, Erwin; Finger, Robert; Appel, Franziska et al. (2020): The Struggle of Farming Systems in Europe: Looking for Explanations through the Lens of Resilience. In EuroChoices 19 (2), pp. 4–11. DOI: 10.1111/1746-692X.12278.
   Reckling, Moritz; Watson, Christine A.; Whitbread, Anthony; Helming, Katharina (2023): Diversification for sustainable and resilient agricultural landscape systems. In Agron. Sustain. Dev. 43 (4), p. 4697. DOI: 10.1007/s13593-023-00898-5.

Speaker: Marie Arndt (Leibniz Centre for Agricultural Landscape Research (ZALF))

138_Arndt.pptx

31 Higher crop diversity in less diverse agricultural landscapes in Northeastern Germany

Planning for sustainable agricultural landscapes requires a comprehensive understanding of the needs of stakeholders. To achieve a sustainable agricultural system, the implementation of different strategies for diversification has been a promising approach. These strategies can target the overall landscape complexity to benefit biodiversity or diversify cropping systems to enhance and stabilise yields. Therefore, diversity at both agricultural field and landscape levels and their interconnection need to be considered (Reckling et al., 2023). However, the impacts of different diversification strategies at different levels are rarely investigated jointly. This study aims to detect the relationship between the diversification strategies at field and landscape levels and to identify potential drivers to understand what synergy and trade-off dynamics of sustainable landscape planning emerge.

As a case study, we studied agricultural landscapes in the Brandenburg region of Germany (Schiller et al., 2023). Crop rotational richness, Shannon's diversity, and evenness indices were measured per-field per-decade as proxies for crop rotational diversity. Landscape diversity was measured using land use land cover types and habitat types with the same metrics. As potential drivers of diversity, we included soil and climate characteristics and the proportion of agricultural and urban areas, along with geographical positions. All spatial information was aggregated within the landscape of 10x10 km in Brandenburg, Germany. We tested the links between all variables using interpretable machine learning methods to identify important modelled associations.

We found that more simplified landscapes with a higher proportion of agricultural area exhibited higher crop rotational diversity (r-squared = 0.2 – 0.6). Also, crop rotational diversity was higher with higher soil quality (r-squared = 0.1 – 0.13). Therefore, different diversity aspects can be found in contrasting regions in Brandenburg, where crop rotational diversity is particularly determined by local soil quality and the intensity of agricultural land use.

The more diverse the crop rotation, the simpler the landscape – This trade-off relationship implies the fundamental trade-off of diversification across scales due possibly to the limited high quality resources like soil for land development. We argue that a comprehensive understanding of the spatial distribution, synergies, and trade-offs of diversification (goals) within a landscape facilitates collaboration and planning among all parties involved in sustainable landscape planning (Duarte et al., 2018). As we move forward, integrating diverse stakeholder perspectives, socio-economic farming conditions, and advanced AI techniques will play a pivotal role in shaping more sustainable landscapes.

Duarte, G. T., Santos, P. M., Cornelissen, T. G., Ribeiro, M. C., & Paglia, A. P. (2018). The effects of landscape patterns on ecosystem services: Meta-analyses of landscape services. Landscape Ecology, 33(8), 1247–1257. https://doi.org/10.1007/s10980-018-0673-5
Reckling, M., Watson, C. A., Whitbread, A., & Helming, K. (2023). Diversification for sustainable and resilient agricultural landscape systems. Agronomy for Sustainable Development, 43(4), 44. https://doi.org/10.1007/s13593-023-00898-5
Schiller, J., Jänicke, C., Reckling, M., & Ryo, M. (2023). Higher crop diversity in less diverse landscapes [Preprint]. In Review. https://doi.org/10.21203/rs.3.rs-3410387/v1

Speaker: Josepha Schiller (​​​​​​​​​​​​​​​Leibniz Centre for Agricultural Landscape Research (ZALF))

32 The effects of increasing the intensity of legume crops or legume/oilseed mixtures in the cropping rotation at research and commercial scale in SE Australia

Sowing a legume crop every third year in a crop rotation of cereal and canola can be profitable while increasing the resilience and sustainability of modern farming systems. Some of the benefits include increased soil nitrogen (N) availability and improved rotational and environmental outcomes. In no-till farming systems, sowing large-seeded legumes into retained cereal residues facilitates stubble retention, reduce N tie-up and improves the conversion of carbon-rich cereal stubbles into stable soil organic matter. We explored whether additional benefits to the sustainability and resilience of the farming system was possible by increasing the intensity of legumes by either sowing a legume, or a legume-oilseed intercrop mix every second year followed by a cereal. These effects were explored at both small-plot and larger on-farm paddock scale and explore the reasons for low adoption of pulse crops on commercial farms in southeastern Australia, despite experimental evidence of economic and environmental benefits of these diverse systems.

Two fully phased replicated field experiments (2018-2023) confirmed that legume inclusion in Diverse 3-year cropping rotations can be as profitable as Baseline rotations (canola-wheat-barley) currently favoured by farmers. The average 6-year gross margin (GM) in the Diverse 3-year rotation was 4.3% lower and total chemical costs 5% higher than the Baseline(H) system, however, systems incorporating a legume were less risky (higher profit:cost ratio) with up to 66% reductions in synthetic nitrogen (N) fertiliser usage. The reduced synthetic N in the Diverse system represented only 9% of the total GM compared to 22% in the Baseline(H) system (Table 1). Increasing legume intensity in a Diverse 2-year rotation resulted in a 15-16% reduction in GM compared to the Baseline(H) or Intense Base(H) and 7% increase in chemical costs. However, there was a 63% reduction in fertiliser cost and 81% decrease in synthetic nitrogen costs compared to Baseline(H), which represented only 6% of GM costs for synthetic nitrogen.

Intercrops have focussed on pulse/oilseed mixtures comprising fababean/canola or chickpea/linseed due to specific synergistic benefits related to improved N fixation, reduced disease epidemics such as Ascochyta Blight, Chocolate spot caused by Botrytis fabae and Botrytis cinerea and to improve legume height and support for improved harvesting. The 6-year GM from intercrop-wheat rotations was significantly lower (34%) compared to the Baseline(H) with similar profit:cost ratio (1.19:1). However, the sustainability and resilience were improved including 75% less synthetic N and 27% less chemicals required (Table 1). The faba-canola mixture generally produced more legacy N compared to the chickpea/linseed. In 2023, an average rainfall year (550mm) with low Ascochyta Blight, the chickpea monoculture grain yield was 3.65 t/ha. T and there was a 58% reduction in chickpea grain yield when linseed was sown with chickpeas in alternate rows with 0.9 t/ha linseed grain yield. In mixed rows and chickpea sown at half rate, the chickpea yield reduction increased to 86% (yield of 0.5 t/ha) and linseed yield increased to 1.55 t/ha (Table 1).

At farm scale, when the business is managed at a high level of efficiency, changing management strategies to include legumes was effective and profitable for growers by reducing the: (i) amount of synthetic N required, (ii) herbicide resistant ryegrass weed seedbank, and (iii) economic fluctuations at the whole-farm level. In 2022 at our paddock scale long-term farming systems experiment, the faba bean/canola intercrop yielded 3.8 t/ha of faba bean and 0.5 t/ha of canola compared to 2.3 t/ha and 3.3 t/ha in faba bean and canola monocultures, respectively. The coefficient of variation was reduced by 30% in the intercrop with 86% less fungicides applied. The canola supported the faba bean crop reducing the disease pressure and yield loss.

Our work suggests outcomes of experimental research on the value of diverse crops into cereal-based systems should be combined with a clear understanding of farm- and industry level constraints in Australia. There are significant challenges moving from a cereal-canola rotation to include a pulse grain at farm scale including capital for machinery and equipment, new farmer skills, pulse grain price volatility, extra grain storage and reduced cash-flow with more grain stored. There’s considerably higher skill levels and extra costs for seed separation at harvest for intercropping farmers. These logistical issues at farm-scale remain a barrier to wider adoption despite promising results at experimental scales.

Speaker: Mr Tony Swan (CSIRO Agriculture & Food)

Managing biotic and abiotic stresses with integrated approaches

Conveners: Karel Klem, Muhammad Fazail Nasar

33 Interspecies diversity in morphological responses of a panel of crop and weed species to water stress

Introduction

Weeds are the most damaging pest for yields in arable crops, as they compete with the crops for light, minerals and water (Oerke, 2006). Because of climate change, crop-weed competition for water is expected to increase.

As water use and crop-weed competition depend on plant morphology (Moreau et al., 2022), we investigated the interspecies diversity in morphological responses to water stress on five weed species (Abutilon theophrasti Medik., Alopecurus myosuroides Huds., Avena fatua L., Geranium dissectum L., Tripleurospermum inodorum (L.) CH Schultz) and two crop species (Triticum aestivum L. - soft wheat and Brassica napus L. - rapeseed), that co-exist in temperate arable cropping systems and pedoclimates.

We focused on traits involved in light competition (Colbach et al., 2019):
- Leaf area to leaf biomass ratio (SLA): efficiency to produce leaf area (for photosynthesis and transpiration) from a given leaf biomass.
- Height to aboveground biomass ratio (HBR): ability to grow taller from a given aboveground biomass (for radiation interception above the canopy).
- Leaf to aboveground biomass ratio (LBR): leaf production efficiency from aboveground biomass.
- Root to total biomass ratio (RBR): propensity to explore soil to uptake water and nutrients.

Material and methods

A greenhouse experiment was performed on a platform equipped with automatic watering systems. Plants were grown in nutrient-rich individual pots, with seven levels of water availability, ranging from 10% to 95% of field capacity. For each species × water treatment combination, five plants were sampled at two phenological stages (early and late vegetative or early vegetative and flowering, depending on the species). Morphological traits were analysed in response to a water stress index. Generic non-linear regressions were fitted, whose response parameters were to characterise interspecies diversity.

Results

For all species, SLA decreased whereas HBR increased with increasing water stress index. RBR and LBR varied less. For most species × stage combinations, the proportion of biomass allocated to roots (vs aboveground organs) increased. LBR response to water stress depended on the combinations (increase, no effect or decrease). G. dissectum and A. theophrasti were the most responsive species for all traits, especially at the flowering stage.

Most species × stage combinations enhanced water uptake ability (RBR increase) and lowered water demand per unit leaf biomass, but some favoured one mechanism. At low stress levels, G. dissectum and flowering A. theophrasti favoured water uptake ability (RBR increase without SLA decrease) whereas early vegetative T. inodorum only reduced demand per unit leaf biomass (SLA decrease without RBR increase). Late vegetative rapeseed and A. fatua kept a better light-interception potential (high HBR).

The species effect explained most of the variability in parameter values, followed by growth stage. In contrast to weeds, water-stressed crop species tended to increase the proportion of biomass allocated to their roots. Most water-stressed dicotyledonous species increased the proportion of aboveground biomass allocated to leaves whereas monocotyledons favoured stems.

Discussion

This study provides new insights on comparative ecology of crop and weed responses to water limitation, and is the first to compare the morphological plasticity of such a wide range of weed species. Trait responses are consistent with the literature (Monaco et al., 2005; Chahal et al., 2018; Moreau et al., 2022). Species × stage combinations had diverse behaviours, which involved different response mechanisms to water stress, in line with Basu et al. (2016)'s plant classification from ‘water savers’ (that reduce transpiration) to ‘water spenders’ (that maximise water uptake). To our knowledge, no studies identified clade- nor status-dependence of RBR and LBR responses to water stress. Additional research is needed to characterise other species and identify generic trends to predict the behaviour of a wider range of weeds. Our formalisms will feed a 3D mechanistic model (Colbach et al., 2021) to predict the outcomes of future climate-dependent crop-weed interactions (Cournault et al. 2024, second presentation in this congress).

References

Basu, S. et al., 2016. https://doi.org/10.12688/f1000research.7678.1
Chahal, P.S. et al., 2018. https://doi.org/10.1017/wsc.2018.47
Colbach, N. et al., 2019. https://doi.org/10.1016/j.fcr.2019.04.008
Colbach, N. et al., 2021. https://doi.org/10.1016/j.fcr.2020.108006
Cournault, Q. et al., 2024. 18th ESA congress, Rennes
Monaco, T.A. et al., 2005. https://doi.org/10.1111/j.1365-3180.2005.00480.x
Moreau, D. et al., 2022. https://doi.org/10.1111/wre.12554
Oerke, E.-C., 2006. https://doi.org/10.1017/S0021859605005708

Speaker: Quentin Cournault (INRAE Agroécologie (Dijon) ; CNRS EPHE/ Univ. Bourgogne Biogéosciences (Dijon) ; AgroParisTech (Palaiseau))

34 Which contribution do agricultural practices and biological control make to regulating populations of Psylliodes chrysocephala in oilseed rape?

Psylliodes chrysocephala is among the main pests of oilseed rape in Europe and is mainly managed with insecticides. Increasing insecticide resistance and health and environmental concerns have highlighted the need for alternatives to chemical control, such as conservation biological control. Conservation biological control can be enhanced by (1) providing resources to beneficial organisms in and around crop fields, like providing parasitoids with resources through sowing flower strips, and (2) by redesigning cropping systems to promote bottom-up and top-down processes contributing to natural pest control.

Using an observational approach based on a network of farmers' fields, we assessed the effects of cropping systems and flower strips on P. chrysocephala and their regulation throughout their development cycle. We selected fields in the Paris Basin grown under organic farming, under soil conservation practices, and conventionally, with many intermediary practices. Some of the fields contained a perennial flower strip sown in 2018. Observations on the autumn phase of P. chrysocephala cycle were carried out in 2020 and 2021, and those on the spring part of the cycle in 2019 and 2020, with 20 to 30 fields monitored each time.

The damage caused by P. chrysocephala is mainly depending on the number of larvae present in the oilseed rape plants in winter. An initial hypothesis was related to the presence of residues on the soil surface, favoured in no-till farming, which could hinder the movement of P. chrysocephala on the soil surface. At the field level, we observed direct effects of certain practices, such as a negative effect of insecticide treatments (halving the number of larvae) and a higher presence of larvae with the occurrence of ploughing. However, we did not observe any effect of residue covering the soil surface on the amount of pest larvae. The percentage of soil covered by total vegetation (crop, companion plants and weeds) or by companion plants and weeds alone had a negative effect on the number of pest larvae, with a threefold reduction of their number when the total vegetation cover increases from 10 to 100%). Finally, of the predators present on the soil surface (carabid beetles, harvestmen), only spider activity-density had a slight negative effect on the number of pest larvae per plant. At the landscape scale, inter-annual variation in oilseed rape area within a radius of 1000 m influenced the number of P. chrysocephala per plant, with an increase in larvae quantities when the oilseed rape area decreased between the previous and the current year.

At the end of winter, P. chrysocephala larvae were on average 30% parasitised by microhymenoptera parasitoids (Tersilochus sp.), with considerable variation between fields. Parasitism was slightly higher (but not significantly) in insecticide-untreated fields with a flower strip than in insecticide-treated fields without a flower strip. In addition, flowering and nectar-providing weeds in the field had a positive effect on parasitism levels.

At the end of their development in oilseed rape stems and leaves, larvae fall to the soil surface before pupating underground, where they are highly vulnerable to predators. Using sentinel prey similar to P. chrysocephala larvae, we observed that approximately half of the prey was consumed within 24 hours, with no difference between cropping systems. Camera observations coupled with sentinel prey revealed that larvae were mainly consumed by carabids (64% of predation events) and secondarily by rove beetles, ants and chilopods. These are generalist predators that are functionally redundant, resulting in homogeneous predation rates between cropping systems, despite observed differences in the composition of ground-dwelling predator communities between cropping systems.

In conclusion, P. chrysocephala populations can be limited throughout their life cycle. Growing oilseed rape with service plants in the autumn and the presence of floral resources in the spring, for example in flower strips, are two ways of promoting this regulation. We have also verified and validated the fact that P. chrysocephala spend the summer in forests and that flower strips are not a favourable habitat for these pests during their summer diapause. The biological control by predators and parasitoids occurs after the damage has been done to the crop. It does contribute to reduce pest populations only in the following year, which argues in favour of multi-annual and territorial management of P. chrysocephala populations.

Speaker: Mr Antoine Gardarin

9_Gardarin.pptx

35 Effects of light quality and quantity on tillering dynamics and investment in reproduction of the perennial grain crop Thinopyrum intermedium

Introduction
Agronomic studies on the use of intermediate wheatgrass (Thinopyrum intermedium) as a perennial grain crop show a grain yield decline over the years, which calls for a better understanding of the link between Th. intermedium vegetative development and investment in reproduction. Recent data suggest that density and row spacing might influence yield components in Th. intermedium (Fernandez et al. 2020; Hunter et al. 2020). Light is a major factor driving morphological and physiological changes with plant density. It could influence grain yield, both indirectly through tillering and directly by affecting yield components. Tillering is critical for the reproductive stage of perennial grasses and is very plastic to the light environment: notably a decrease of the red:far-red light ratio (R:FR ratio) is known to reduce tillering (Casal et al. 1985). Therefore, this study addresses the effects of light quantity and quality on the tillering dynamics and yield components of Th. intermedium.

Materials & Methods
Plants were sown in a growth chamber and vernalized for 7 weeks at 3 leaves. In total, 72 plants were transplanted and placed in a tunnel under light filters. Five R:FR treatments were tested: 1.09 (natural light), 0.55, 0.44, 0.30, 0.17. Between 27 and 29% of PAR was transmitted by the filters. A control was added with a R:FR of 1.1 and 96% of transmitted PAR.
Each new tiller was marked every week, specifying order and position on the mother tiller. Haun stage was noted for every tiller, every week up to flag leaf stage. Then, heading and flowering were noted. New tillers developing after flowering of the main stem were not monitored. Height of the main stem was measured up to flag leaf. All plants were harvested when a majority of spikes was mature. At harvest, the total number of tillers, rhizomes and spikes were counted. Plants were dried (40°C for 3 days) before weighing vegetative dry biomass. Measures for each spikes included dry weight, number of spikelets, number of florets on 3 spikelets (basal, middle, apical), number of grain and grain weight.

Results
In the control, height of the main stem was significantly shorter throughout its development and the difference with the other treatments kept increasing over time. Interestingly, no significant effect of R:FR was observed on height except for lowest R:FR treatment (R:FR=0.17). R:FR treatments had more impact on tiller number. Lower PAR reduced tiller emergence, so did lower R:FR. Differences between R:FR treatments were only significant between the 1.09 and the 0.44 and 0.30. Both primary and secondary tillers emergence were inhibited by decreasing PAR and R:FR, and tertiary tillers mostly appeared in the control. Surprisingly, the lowest R:FR treatment had the highest number of tillers after the control and the 1.09. Phyllochrons of main stems, primary and secondary tillers were affected by R:FR treatments, but within each treatment only the control had significantly different phyllochrons between tiller orders. Effects on yield components are still under study (sample being processed) and will be presented during the conference.

Discussion
These results highlight that tillering plasticity to the light environment is high in Th. intermedium. This means that current populations of Th. intermedium should be very sensitive to plant density, leading to competition for light and adaptation to light quality. Therefore, increasing light penetration at the base of the canopy at specific times of the crop cycle (using planting density, cuttings and post-harvest management practices) may be an agronomic lever to manage tillering dynamics and investment in reproduction over the years, although it has to be tested in field conditions. Furthermore, this study provides physiological information on the tillering dynamics and leaf development of Th. intermedium for different tiller orders, which can be used to favour productive tillers.

References
Casal JJ, Deregibus VA, Sanchez RA (1985) Variations in Tiller Dynamics and Morphology in Lolium multiflorum Lam.Vegetative and Reproductive Plants as affected by Differences in Red/Far-Red Irradiation. Annals of Botany 56:553–559. https://doi.org/10.1093/oxfordjournals.aob.a087040

Fernandez CW, Ehlke N, Sheaffer CC, Jungers JM (2020) Effects of nitrogen fertilization and planting density on intermediate wheatgrass yield. Agronomy Journal 112:4159–4170. https://doi.org/10.1002/agj2.20351

Hunter M, Sheaffer C, Culman S, Jungers J (2020) Effects of defoliation and row spacing on intermediate wheatgrass I: Grain production. AGRONOMY JOURNAL 112:1748–1763. https://doi.org/10.1002/agj2.20128

Speaker: Christelle Ginot

36 Implementation of Halophyte/Tomato cultivation systems in Moderately Saline Soils

Objectives:
Most arable lands in Mediterranean countries are located in arid and semiarid regions, where water and soil salinity, water shortage and nutrients deficiency in soils are the major constraints affecting food and fodder production. In this context, halophytes emerge as alternative cash crops to be used in sustainable saline production systems, due to their ability to cope with soil and water salinization and to restore biodiversity. The overall objective of our research is to develop sustainable and environmentally friendly new farming and producing systems based on the use of halophytes.
Methods:
For this purpose, two complementary approaches using the halophyte Arthrocaulon macrostachyum have been implemented:
(a) Intercropping and sequential cropping systems between tomato (Solanum lycopersicum var. Sargento) and the halophyte in saline soil conditions. The goal was to improve tomato yield in a cost-effective biological way while providing halophytes as value-added crops.
(b) Micropropagation of elite halophyte germplasm. The control of plant micropropagation is a prerequisite for fundamental research but also for applied purposes such as saline agriculture, site rehabilitation, or endangered plant preservation.
Results:
(a) Sequential cropping altered tomato plants physiology, which was reflected in changes in the antioxidant metabolism and photosynthesis performance as well as in the quality of the fruit. Remarkably, sequential cropping increased 20% tomato production with respect to monoculture.
(b) We achieved efficient micropropagation protocol for A. macrostachyum using shoot explants derived from in vitro-grown seedlings. Superior genotypes were selected from explants grown in high strength and NaCl content medium, which were then rooted and acclimatized to ex vitro conditions. A comprehensive characterization including determination of oxidative stress parameters, photosynthesis efficiency and mineral nutrient contents was done during this process.
Conclusions: This research (1) sheds light into the physiological and biochemical mechanisms underlying tomato/halophyte interaction, (2) provides a solid in vitro platform for the production of elite A. macrostachyum germplasm for ulterior uses, independently on seasonal variations and with prospect of scaling up, and (3) highlights the applicability of halophytes in biosaline agriculture.

Speaker: Dr José A. Hernández (CEBAS-CSIC)

154_Hernández.pptx

37 Modelling fungal diseases in intercrops

Introduction
Intercropping is a management practice inspired by the interaction between the biodiversity of an ecosystem and its resilience under stress. Intercropping is of strategic interest in the face of climatic and environmental issues, having already shown the capacity to bring beneficial outcomes on production and ecosystem services (for example Gardarin, A. et al, 2022). However its ability to regulate pests and diseases, and thus reduce pesticide use with limited yield loss, is less well characterised and generally assessed separately from other services. An integrated approach would allow the design and adaptation of these systems considering all of the services they provide.
Such an approach can be found in the modelling of plant-microbe interactions within a soil-climate system. To our knowledge, modelling work conducted so far on diseases within intercropping systems has been limited mostly to cultivar mixtures and functional processes focused on epidemiological dynamics. We have found limited works dealing with interspecific diversification, crop development and larger ecosystem processes, alongside the main drivers of an epidemic.
Based on previous modelling work (Caubel, J et al, 2017) on the coupling of a generic disease model (MILA) with a crop model (STICS), our aim is to adapt MILA from a single crop context to a bi-specific intercrop system, using STICS intercropping options (Vezy et al., 2023).

Proposed method
Our work rests on the following steps: a comprehensive review of the literature to create an inventory of the processes for fungal disease regulation in diversified canopies, and the short-listing of two modelling approaches to develop and test within the MILA-STICS framework.
STICS is an integrated, deterministic, process-based model which runs at a daily time-step using input variables related to climate and soil as well as the cropping system including its management practices. MILA simulates the dynamics of disease severity and the development of fungal pathogens depending on crop phenology, developmental stages and canopy microclimate. Thanks to STICS daily calculations of canopy characteristics (LAI, microclimate, etc), MILA can provide feedback on the progress of an epidemic throughout the simulation period.
The two alternatives to be tested will be chosen in order to compare two contrasting approaches: one resting on hypotheses which simplify the system, the other on more realistic hypotheses. Some leads may be found in Levionnois, S. et al (2023) and Calonnec, A et al (2012).

Expected results
The main fungal disease regulation processes at play in diversified canopies stem from the dilution and barrier effects on spore dispersal and interception as well as the effect of the modification in canopy microclimate on infection success. STICS already covers calculations of mixed canopy microclimate so adapting MILA resides only in the modification of the dispersal and interception modules by inserting the dilution and barrier effects.
Our testing procedure will involve studying the model behaviour in terms of coherence for the simulation of spore dispersal, and its sensitivity to canopy parameter modifications (e.g. height of the two species, leaf and/or plant density, interrow distance, etc).
The new version of the MILA-STICS model will simulate the growth dynamics of the crop and the development of the epidemic as a function of practices, soil and climate, considering the close interactions within the system comprising the host crop, the pathogenic fungus and the non-host crop. Built in a generic manner, the model will be used to search for crop management that maximise the regulation of the pathogen while maintaining the provision of multiple services in a context of global change. Studying the intercropping system as a whole allows to work on trade-offs between disease control and other benefits of diversifying cultures for a given system, to test various crop arrangements and management practices to optimise outcomes and to run long term simulations to include climate change.

References
Levionnois, S. et al (2023) Phytopathology 113(10): 1876-1889
Calonnec, A et al (2012). European Journal of Plant Pathology 135(3): 479-497.
Caubel, J et al (2017) European Journal of Agronomy 90: 53-66.
Gardarin, A. et al (2022). Agronomy for sustainable development 42(3).
Vezy, R. et al (2023). Agronomy for Sustainable Development, 43(5), 61.

Speaker: Audrey Deheinzelin (INRAE)

267_DEHEINZELIN.pdf

Modeling N & soil

Conveners: Jeremy Whish, Icíar Giménez de Azcárate Bordóns

38 Does the application of nitrogen fertilizers on the crop sowing row change the crop-weed competition in low-herbicide cropping systems?

Introduction. Promoting biological weed regulation by shifting resource availability and use from weed to crop may provide an option for a more sustainable weed management. Light is generally the main resource for which crops and weeds compete in conventional cropping systems. But, with the need to reduce mineral nitrogen fertilizer use, better management of crop-weed competition for nitrogen may become crucial. Especially, applying nitrogen fertilisers locally on the crop sowing row (rather than broadcasted across the whole field) could make more nitrogen available to the crop to the detriment of weed plants (mainly located in the inter-row) (Ditomaso 1995). This option could be valuable for crops with wide-spaced rows and early nitrogen requirements (as nitrogen fertilisers could be applied at sowing time), such as sugar beet. Studies on the placement of nitrogen fertilisers on the sowing row focussed on the environmental and economic advantages of this technique. However, the consequences on crop-weed competition have been less studied, and no references are available on sugar beet. In this context, the present study was conducted with a two-fold objective in order to determine:
(O1) To which extent placing nitrogen fertilisers on the sowing row affects the dynamics in space and time of nitrogen in soil,
(O2) The consequences of on-row nitrogen application on crop-weed competitive relationships.

Material and Methods. O1 was addressed in a field experiment (2021 and 2022), while O2 was addressed by combining the results from a field experiment (2022) and a systematic review of the literature.
The field experiment was conducted on sugar beet in the Somme region (North-Western France). Two nitrogen application techniques were compared: a field-wide broadcast vs. an on-row application. The dynamics of soil mineral nitrogen were monitored with measurements at two depths, four distances from the sowing row, and two or three dates after sowing (from 7 to 45 days). In addition, in 2022-2023, sugar beet and weed biomass was measured about four months after sowing. In parallel to our field experiment, the literature was reviewed following the method of Mahé et al. (2022) without restriction on crop species and geographical region.

Results and discussion. Results from our field experiment showed that the amount of nitrogen in the soil was greater around the point of application when nitrogen fertiliser was applied on the sowing row (vs. broadcasted). This effect persisted over time but faded away. It was visible in the superficial soil layer in both years, but was visible in the deeper layer only the rainy year.
Despite significant effects on soil nitrogen dynamics, applying nitrogen fertilizers on the sowing row (vs. broadcasted) did not significantly affect sugar beet and weed biomass in our field experiment. This finding contrasted with that of our systematic review of the literature showing that, in most cases (10 out of 12 articles in total), crop growth was increased and/or weed growth decreased when nitrogen fertiliser was applied on the sowing row. This discrepancy between results from our field experiment and those of the literature may be due to differences in the studied crop species, their spatial arrangement (interrow distance) and geographical area.

Conclusion. Placing nitrogen fertiliser on the sowing row (vs. broadcasted) does modify soil nitrogen dynamics, but the consequences on crop-weed competition vary. Therefore, this technique can help to promote crop vs. weed growth, but not systematically, and further studies are needed to better understand the conditions of success.

Funding. INRAE, Agrotransfert Ressources et Territoires, and COPRAA project funded by the Office Français de la Biodiversité (OFB)

Cited references. Ditomaso JM (1995) Weed Science 43: 491-497. Mahé I et al. (2022) Agronomy for Sustainable Development 42: 50.

Speaker: Dr Delphine Moreau (INRAE Agroécologie Dijon)

39 Using low-cost NIRS method for helping smallholder to detect nutritional deficiencies and imbalances

Lack of control over fertilization is one of the major factors in the yield gap between smallholders and large oil palm plantations (Monzon et al., 2023). The diagnostic tool known as leaf analysis method is used by a large number of plantations to manage their fertilization and relies on annual leaf analysis and specific long-term experiments (Dubos et al., 2022). However, this method is not accessible to smallholders, mainly due to the cost of annual leaf analysis. As a consequence, major imbalances in fertilization are generally observed. The most important nutrients to monitor in this crop are N, P, K and Mg (Woittiez et al., 2017). However, current methods to measure leaf nutrient status are long, costly and require hazardous chemical reagents. Recent developments in near-infrared spectrometry (NIRS) have made it possible to create increasingly low-cost measurement equipment, without the need to transform the leaflets (Prananto et al., 2020).
We tested the possibility to use a small portable infrared spectrometer (Nirone S2.2 Evaluation Kit from Spectral Engines) in order to make fertilization management more accessible for smallholders. This spectrometer has a reduced spectral range of 1750-2150nm which has been selected in a prior study testing the correlation between leaflet contents with various spectral ranges. A total of 92 leaflets composite samples were taken from several plots of smallholders and large plantations in West Africa. The plots were located in marginal hydric conditions of Benin and in more favorable conditions of Nigeria, in plantations with different nutritional status, age and plant materials, allowing a large range of variability. Spectral Measurements were taken directly on fresh leaflets on the frond 17, using in classical leaf analysis. Laboratory measurements were got according to the standard methodology of Leaf Analysis. PLS regressions after preprocessing the spectra were used to set up predictive models for the concentration of N, P, K and Mg in the leaves. Goodness of predictions was evaluated by crossvalidation with 10 folds.
In our conditions, the measured values (in % of DM) ranged from 1.5 to 3.0 (N), from 0.10 to 0.17 (P), from 0.23 to 1.03 (K) and 0.12 to 0.69 (Mg) which corresponds to leave nutrients content generally observed in oil palms plantations. A satisfying accuracy between measured and predicted nutrients contents was generally observed but depended on the considered nutrient. For instance, N was the better predicted nutrient (RMSECV=0.19). In contrast, Mg was quite poorly predicted (RMSECV = 0.092). In terms of error, the proportion of samples predicted with an error > 20% was lower for N and P (2% and 1%, respectively), compared to K (30%) and Mg (60%).
Our results showed that using a portable and cheap infrared spectrometer could be used to easily and quickly predict nutrients contents in a wide-range of nutritional conditions. However, compared to the standard leaf analysis methodology, prediction accuracy is lower especially regarding Mg and K. In a context of advices to smallholders, the trade-off between time, cost and precision is in favor to lower cost even if it means being less precise. This technology appears interesting to (i) detect situations with severe deficiencies and/or imbalances and (ii) educate smallholders to best management practices.

References:

Dubos, B., Bonneau, X., Flori, A., 2022. Oil Palm Fertilization Guide. éditions Quæ, Versailles.
Monzon, J.P., Lim, Y.L., Tenorio, F.A., Farrasati, R., Pradiko, I., Sugianto, H., Donough, C.R., Rattalino Edreira, J.I., Rahutomo, S., Agus, F., Slingerland, M.A., Zijlstra, M., Saleh, S., Nashr, F., Nurdwiansyah, D., Ulfaria, N., Winarni, N.L., Zulhakim, N., Grassini, P., 2023. Agronomy explains large yield gaps in smallholder oil palm fields. Agricultural Systems 210, 103689.
Prananto, J.A., Minasny, B., Weaver, T., 2020. Chapter One - Near infrared (NIR) spectroscopy as a rapid and cost-effective method for nutrient analysis of plant leaf tissues. In: Sparks, D.L. (Ed.), Advances in Agronomy. Academic Press, pp. 1-49.
Woittiez, L.S., van Wijk, M.T., Slingerland, M., van Noordwijk, M., Giller, K.E., 2017. Yield gaps in oil palm: A quantitative review of contributing factors. European Journal of Agronomy 83, 57-77.

Speaker: Mr Valentin Avit (SADEF, France)

84_Avit.pdf

40 A crop forecast-based approach for in-season nitrogen application in winter wheat

Introduction

While agricultural production is among the main drivers of anthropogenic climate change, projected effects of climate change and climate variability increase the pressure to provide food in sufficient quantity and quality at the same time. Inadequate nitrogen (N)-fertilisation practices, that fail to consider seasonally variable weather conditions and their impacts on crop yield potential and N-requirements, cause reduced N-use efficiency. As a result, both the ecological and economic sustainability of crop production are at risk. Forecasts of crop yield and development have thus been promoted as promising means towards more targeted fertilisation practices. The aim of this study was to develop a season-specific crop forecasting approach that allows for a targeted N-application in winter wheat while maintaining farm revenue compared to empirical N-fertilisation practices. Traditionally, crop forecasts are based on climatological records. Evidence that future growing conditions will deviate from historic averages and the improvement of weather forecasting skill gave reason to move to crop forecasts that use seasonal weather forecasts for this study instead.

Material and Methods

The present crop forecasts were generated using the process-based crop model SSM iCrop (Soltani and Sinclair, 2012) combined with state-of-the-art seasonal ensemble weather forecasts (SEAS5, Johnson et al., 2019) downscaled to a 1 km grid over the case study region of Eastern Austria. Forecasts included key N-management variables, such as phenological stages (PHEN), above-ground dry weight and grain yield (GRNY), total N-uptake (CNUP), as well as plant-available soil water and mineral N-content. Precise predictions of PHEN were required for an accurate timing of N-fertilisation, while GRNY and CNUP forecasts defined the amount of N (N-amount) applied.
Throughout the season, these variables were forecasted through monthly iCrop runs for three winter wheat on-farm experiments in Eastern Austria. iCrop was supplied with observed daily weather data from sowing until the last day of each previous month, and downscaled seasonal forecasts from then until harvest. To quantify the operational potential of using these crop forecasts for in-season N-fertilisation, each experimental field was divided into two treatments: (i) FARM, where N-amount was applied according to common farm practice, and (ii) crop forecast (CROF), where N-amount was applied such that forecasted mean GRNY and protein content (PROT) met FARM levels but forecasted CROF economic return to applied N (ERAN) was increased through a reduction of N-amount compared to FARM.
Each field was treated as a complete block. Significant differences in ERAN were tested through an ANOVA model, including block and treatment as fixed effects.

Results and Discussion

Results from the three on-farm experiments showed a reduction in NAmount of -23.42% (-43.33 kgN ha^-1) when implementing CROF compared to FARM. While maintaining revenue from high-quality grain sales (PROT>14%), lower N-amount led to a significant benefit of +30.22% (+2.20 € kgN^-1) in ERAN (Figure 1, see attached).

Figure 1 caption: Total amount of nitrogen applied (N-amount), revenue, and economic return to applied N (± standard deviation) of winter wheat in Eastern Austria, fertilised according to crop forecasts (CROF) and farm practice (FARM). Lower case letters indicate significant differences between treatments (p<0.05).

Prior to this study, iCrop was extensively parameterised and tested against comprehensive field datasets in the target wheat production region (Manschadi et al., 2022). For applying the present approach and extrapolating the results of this study to other production environments, iCrop (or any other crop model used) first needs to be adapted and parameterised to capture local conditions well. However, under the projected increase in non-average growing conditions, in-season N-application is expected to further benefit from crop forecasts in the future overall.

References

Johnson, S.J. et al., 2019. SEAS5: the new ECMWF seasonal forecast system. Geoscientific Model Development 12, 1087-1117.
Manschadi, A.M. et al., 2022. Performance of the SSM-iCrop model for predicting growth and nitrogen dynamics in winter wheat. European Journal of Agronomy 135.
Soltani, A. and Sinclair, T.R., 2012. Modeling physiology of crop development, growth and yield. Modeling Physiology of Crop Development, Growth and Yield, 1-322.

Speaker: Marlene Palka (Leibniz Centre for Agricultural Landscape Research (ZALF))

41 Developing a model to simulate carbon cycling and water competition in vineyard

1. Introduction
The synergy between different technologies such as field sensors and crop models is fundamental for crop monitoring growth and yield, while assessing climate change impacts at both field and broader scales. In the perspective of climate change mitigation, the implementation of biogeochemical cycles within crop models is essential to evaluate water and carbon (C) fluxes and C sequestration capacity of the agro-ecosystems. This requires an accurate monitoring of those cropping systems in which the atmospheric C can be stored and long-time sequestered in biomass compartments (i.e. vineyards and orchards). In this work, the first version of UNIFI.GrapeML model (Leolini et al., 2018), previously based on the radiation use efficiency approach for simulating biomass growth and development, was implemented with modules simulating water competition between tree and grass layers and soil carbon fluxes. Methodological approach (Fig. 1) and preliminary results are presented here.

2. Materials and Methods
The UNIFI.GrapeML model was initially coupled with the GRASSVISTOCK model (Leolini et al., submitted), which included the grass and soil carbon modules (RothC model, Coleman & Jenkison, 1996), to account grass growth dynamics, water competition and carbon fluxes in vineyards. The grass module was calibrated and validated under different climates in Italy (Torgnon: 45.84°N, 7.58°E and Borgo S. Lorenzo: 43.95°N, 11.35°E) to simulate daily fractional transpirable soil water (FTSW), net ecosystem exchange (NEE), gross primary production (GPP) and ecosystem respiration (Reco) in agro-pastoral systems. Currently, this module is integrated in UNIFI.GrapeML, and under testing, for evaluating its capability in vine biomass C-partitioning and inter-row grass growth in Mediterranean vineyards.

Figure 1 – UNIFI.GrapeML workflow

3. Results
The first results provided by the grass module showed satisfactory performances at simulating biomass (Torgnon: r = 0.68; RMSE = 72.79 g m-2 dry matter; Borgo S. Lorenzo: r = 0.78; RMSE = 67.46 g m-2 dry matter) and FTSW (Torgnon: r = 0.88; RMSE = 0.13; Borgo S. Lorenzo: r = 0.95; RMSE = 0.13) in pastures. Daily C-fluxes simulations, carried out only at Torgnon, confirmed the goodness of the simulations (NEE: r = 0.60; RMSE = 0.02 Mg C ha-1; GPP: r = 0.84; RMSE = 0.02 Mg C ha-1; Reco: r = 0.67; RMSE = 0.02 Mg C ha-1).

4. Discussion
The simulation of ecophysiological processes (i.e. biomass growth, water and C fluxes) of plant species is challenging in cropping systems composed of multiple vegetation layers such as vineyards and orchards. To our best knowledge, current grapevine growth models are not able to well represent ecosystem fluxes, since processes such as water competition between vegetation layers and soil organic carbon turnover from different residues are still not included (Moriondo et al., 2015). In this context, the implementation of UNIFI.GrapeML is a fundamental step to reduce uncertainties in the dynamics of biomass growth, soil water content and soil C fluxes estimates, thereby promoting optimization of agronomic practices with regards to productivity and climate mitigation.

Acknowledgements
The publication was made by researcher Luisa Leolini with a research contract co-funded by the European Union - PON Research and Innovation 2014-2020 in accordance with Article 24, paragraph 3a), of Law No. 240 of December 30, 2010, as amended and Ministerial Decree No. 1062 of August 10, 2021.

5. References
Coleman, K., et al. RothC-26.3-A Model for the turnover of carbon in soil. In Evaluation of soil organic matter models: using existing long-term datasets. Springer Berlin Heidelberg, 237-246, 1996.

Leolini, L., et al. A model library to simulate grapevine growth and development: Software implementation, sensitivity analysis and field level application. European Journal of Agronomy, 99, 92-105, 2018.

Leolini, L., et al. Modeling carbon and water fluxes in agro-pastoral systems under contrasting climates and different management practices. Agriculture and Forestry Meteorology, submitted.

Moriondo, M., et al. Modelling olive trees and grapevines in a changing climate. Environmental Modelling & Software, 72, 387-401, 2015.

Speaker: Luisa Leolini (University of Florence)

42 Sensitivity of nitrogen leaching reduction by winter cover crops to management interventions at landscape scale

1. Introduction
   Nitrogen (N) leaching losses to groundwater are an environmental risk in intensively managed agricultural systems. Among others, an adaptation strategy to mitigate such pollution risks is to reduce the fallow (bare soil) period duration by sowing cover crops after the winter grazing of forage crops (Carey et al., 2018). Cover crops can take up excess residual N after previous crops, reduce N concentration in drainage water, and reduce drainage volume through transpiration (Thapa et al., 2018). However, the effectiveness of cover crops to mitigate N leaching depends on plant growth, and is largely influenced by local environmental and soil conditions, in addition with farmer’s management decisions (Malcolm et al., 2022). This makes it difficult to quantify the benefits of cover crop adoption across large areas to inform regional environmental planning.

2. Methods
   In this study, we use a variance-based sensitivity analyses to spatially estimate the contribution of different management factors (plant population and sowing time) to the effectiveness of cover crops to mitigate N leaching losses (Crosetto et al., 2000; Teixeira et al., 2017). The Agricultural Production Systems sIMulator next generation (APSIM-NextGen) oats model was first tested against field data for two New Zealand locations with contrasting climates (Southland and Canterbury) to verify prediction accuracy. The model was then set up to calculate the effectiveness of cover crops to reduce N leaching in relation to a fallow (control) treatment at 5 km resolution considering contrasting management options characterised by sowing times from June to October and populations of 150 and 300 plants/m². Two soil types were considered: 1) a deep stony sand soil, and 2) a very deep, heavy silt loam.

3. Results
   Results showed that the sensitivity to management varied spatially, with considerable share of variability explained through factor interactions, particularly for more complex model outputs such as N leaching amounts. Overall, N leaching losses were more sensitive to sowing time than plant population in both soils, with this pattern being more pronounced in the deep stony sand soil. The results also indicate that the cooler region (Southland) was more sensitive to sowing time than warmer one (Canterbury). In both regions, the sensitivity index of N leaching also exhibited spatial patterns in response to changes in temperature profiles with elevation.

4. Discussion
   These results indicate that cover crops effectiveness to reduce N leaching varies within and across large regions. Similarly, spatial variation in the sensitivity to management parameters differed in response to environmental conditions. Therefore, management interventions should be included in detail in spatial analysis models, to allow more accurately estimate variability in cover crop effectiveness across a landscape.

5. References
   Carey, P. L., Cameron, K. C., Di, H. J., & Edwards, G. R. (2018). Does sowing an oats catch crop reduce nitrate leaching from urine deposition following simulated winter forage grazing? - A growth chamber experiment. Plant and Soil, 431(1), 37–52. https://doi.org/10.1007/s11104-018-3742-2
   Crosetto, M., Tarantola, S., & Saltelli, A. (2000). Sensitivity and uncertainty analysis in spatial modelling based on GIS. Agriculture, Ecosystems & Environment, 81(1), 71–79. https://doi.org/10.1016/S0167-8809(00)00169-9
   Malcolm, B. J., Cameron, K. C., Beare, M. H., Carrick, S. T., Payne, J. J., Maley, S. C., Di, H. J., Richards, K. K., Dalley, D. E., & de Ruiter, J. M. (2022). Oat catch crop efficacy on nitrogen leaching varies after forage crop grazing. Nutrient Cycling in Agroecosystems, 122(3), 273–288. https://doi.org/10.1007/s10705-022-10201-9
   Teixeira, E. I., Zhao, G., Ruiter, J. de, Brown, H., Ausseil, A.-G., Meenken, E., & Ewert, F. (2017). The interactions between genotype, management and environment in regional crop modelling. European Journal of Agronomy, 88, 106–115. https://doi.org/10.1016/j.eja.2016.05.005
   Thapa, R., Mirsky, S. B., & Tully, K. L. (2018). Cover Crops Reduce Nitrate Leaching in Agroecosystems:A Global Meta-Analysis. Journal of Environmental Quality, 47(6), 1400–1411. https://doi.org/10.2134/jeq2018.03.0107

Speaker: Dr Jingjing Zhang (The New Zealand Institute for Plant and Food Research Limited, New Zealand; Auckland University of Technology, New Zealand)

43 Predicting plant available water holding capacity of soils from crop yield

Email: di.he@csiro.au
[Introduction]
Within field variations of plant available water capacity (PAWC) of soil is one of the major causes of spatial yield variability in dryland agriculture systems, as PAWC interacts with pre-season and in-season rainfall and other climatic variables to determine crop growth and final yield. Quantification of such variations helps to better understand the changes in soil texture and subsoil constraints to inform spatially explicit management practice.
[Method]
We developed and tested a general inverse approach to estimate PAWC from crop yield and yield maps. The agricultural production systems model (APSIM) was used to simulate wheat yield on synthetic soils with contrasting PAWC and climates. The simulated results were used to develop an empirical model to relate simulated yield to PAWC. The empirical model was inversely used to predict PAWC from observed crop yield. Potential prediction ability was quantified using independently simulated wheat yield on actual soils. The actual ability was assessed with measured wheat yields and PAWC. We also further extend this approach to predict and map in-field variations of PAWC from yield maps of single and multiple crops. Soil PAWC maps were produced based on inversely predicted PAWC using crop yield maps together with in-field management information, and compared with: 1) available water capacity derived using laboratory-measured soil properties, and 2) soil types derived from proximally sensed soil spectra and ground geophysics for four representative farms in Australia.
[Result]
The approach had higher accuracy for sites with high rainfall or dominant summer rainfall. It could potentially provide acceptable PAWC predictions across contrasting climate regions (prediction error < 37 mm, 33.5%). The prediction error using crop yield against measured PAWC was <25 mm (26.5%). Our results demonstrate that soil PAWC can be reliably predicted from crop yield. The predicted PAWC maps matched well with within-field spatial variation of soil types, and well reflected the impact of soil constraints (e.g. salinity), and soil classifications from soil survey and local experience. This demonstrates that the predicted PAWC from crop yield using inverse modelling can reflect the soil physicochemical variations within-field.

[Discussion]
This approach provides an alternative way to predict PAWC rather than directly measuring it via soil sampling, with profound implications for reducing labour and costs. The generated PAWC maps can be combined with process-based modelling to predict crop yield and yield zones and to inform spatial field management and soil sampling.

Speaker: Enli Wang (CSIRO)

Sustainable increase of productivity

Conveners: Tom Schut, Gabriele Nerucci

44 Combining grapevine yield, soil quality and service crops: results from a three-year on-farm experimentation in the Mediterranean region

Enhancing soil organic matter is key to sustainable viticulture. This study evaluates strategies to improve soil quality and viticultural performance in the Mediterranean. Winegrowers, acknowledging the impact of soil health on yield and resilience, are adapting to evolving policies like the anticipated glyphosate ban by turning to alternatives like cover crops for effective weed management (Cataldo et al., 2021; Jacquet et al., 2021). Cover cropping is increasingly adopted for its benefits in reducing herbicides, boosting soil quality, and water resource management (Garcia et al., 2018). Organic amendments are also used to enrich soil and recycle nutrients (Mondini et al., 2018). Challenges in cover cropping and organic amendment implementation prompt research into resource management and soil property changes (Crystal-Ornelas et al., 2021). At the farm level, the diversity of viticultural practices reveal continuous uncertainties among winegrowers about the effectiveness of ecosystem services and the long-term viability of cover crop management strategies. The Occitanie-funded RESAMOVITI project, involving the ABSys research unit, the French Institute for Vine and Wine (IFV), agri-suppliers (Frayssinnet Club Authentis), and winegrowers, focuses on sustainable soil management, assessing cover crop and organic amendment interaction to improve soil health and yield in diverse Mediterranean conditions.

Materials and Methods:
Seven vineyards across the Mediterranean region participated in the project, with winegrowers actively involved. Soil characteristics were analyzed in 2019 and 2023, while grapevine and cover crop indicators were monitored during the years 2020-2022. Four modalities combining or not amendment and cover crop in comparison with a bare soil control were tested in the inter-rows of each experimental field.

Results
Results indicated that cover crop development was strongly influenced by sowing (Figure 1) and termination dates, initial rainfall and cumulative degree days. Cover crop biomass varied across plots and years, with no discernible impact of organic amendments (from less than 1 Mg ha-1 to more than 7). Potential carbon and nitrogen returns from cover crops depended on their development and management, including modulation of the C/N ratio based on the destruction date. Moreover, the presence of cover crops notably enriched soil labile and stable organic carbon content even after three years only. Results about nitrogen balance varied a lot from one field to another, depending on the initial soil content; at the network level, the study demonstrates that cover crops in Mediterranean conditions did not affect vine nitrogen status at flowering or veraison compared to a tilled control. A decrease in yields and vigor due to cover crops was observed in some fields. Nevertheless, this competition appears to decrease in the presence of amendments. Additionally, other factors might influence resource competition between vines and cover crops, thereby affecting yield and vigor. For example, the method of destruction notably influences soil nitrogen availability and could therefore impact vine performance (Garcia et al., 2024).
Conclusion:
The RESAMOVITI project provides valuable insights into cover crop dynamics and their impact on Mediterranean soil-vineyard systems highlighting that covercropping improves soil quality, and is compatible with grapevine yield if well managed. . These findings inform optimized management strategies and support sustainable viticulture practices.

Cataldo, E., Fucile, M., Mattii, G. B. (2021). A review: Soil management, sustainable strategies and approaches to improve the quality of modern viticulture. Agronomy, 11(11), 2359.
Crystal-Ornelas, R., Thapa, R., Tully, K. L. (2021). Soil organic carbon is affected by organic amendments, conservation tillage, and cover cropping in organic farming systems: A meta-analysis. Agriculture, Ecosystems & Environment, 312, 107356.
Garcia, L., Celette, F., Gary, C., Ripoche, A., Valdés-Gómez, H., Metay, A. (2018). Management of service crops for the provision of ecosystem services in vineyards: A review. Agriculture, Ecosystems & Environment, 251, 158-170.
Garcia L., Krafft G., Enard C., Bouisson Y., Metay A., (2024), Adapting service crop termination strategy in viticulture to increase soil ecosystem functions and limit competition with grapevine. European Journal of Agronomy (in press).
Mondini, C., Fornasier, F., Sinicco, T., Sivilotti, P., Gaiotti, F., Mosetti, D. (2018). Organic amendment effectively recovers soil functionality in degraded vineyards. European Journal of Agronomy, 101, 210-221.
Jacquet, F., Delame, N., Vita, J. L., Huyghe, C., Reboud, X. (2021). The micro-economic impacts of a ban on glyphosate and its replacement with mechanical weeding in French vineyards. Crop Protection, 150, 105778.

Speaker: Prof. Aurélie Metay (ABSys, Univ Montpellier, CIHEAM-IAMM, CIRAD, INRAE, Institut Agro, F-34060 Montpellier, France)

195_METAY.pdf

45 Trajectories of technical changes in pesticide reduction across French vineyards

High quantities of pesticides are applied in vineyards. A shift towards pesticide-free cropping systems, grounded in agroecological principles, is imperative for enhancing the sustainability of agriculture. To achieve this objective, farmers need to change their practices (Tittonell 2014). At the farm level, numerous agroecological practices, more or less effective, already exist but they must be combined (Wezel et al., 2014). The implementation of practices is often done step-by-step following a long process (Sutherland et al. 2012). However, winegrowers are facing several lock-ins toward pesticide use reduction. It is important to explore their trajectories to understand how farmers bypassed these lock-ins. This study aims to analyse the diversity of trajectories of technical changes during the pesticide use reduction transition.

Our study is based on the DEPHY-Network, a French farm network created to demonstrate the capacity of farms to reduce their pesticide use. We focused on farms that joined the network between 2010 and 2012, analysing a minimum 10-year trajectory and selecting 37 farms from the network using a three-criteria sampling grid for the survey. The criteria included the wine-growing area (Mediterranean, Atlantic, or Northern climate), production mode (conventional or organic farming), and pesticide use trajectory type defined by Fouillet et al. (2023). Cluster 1 corresponds to farms that entered the network with a low TFI and that experienced a low TFI decrease (-16.4%). Cluster 2 corresponds to farms that started with a low TFI and that managed to reduce significantly their TFI (-48.7%). Cluster 3 represents farms with a high initial TFI and a high TFI reduction (-63%).

All technical changes related to pesticide use since entering the network were identified and characterized using the “Efficiency (E), Substitution (S), Redesign (R)” (ESR) framework (Hill & MacRae, 1996). Each change was assigned an E, S, R level based on its nature and intensity, and an integrated ESR score of change was calculated each year for each vineyard following Merot et al.'s (2019) methods. We studied each individual trajectory of ESR scores by using Moulin et al. (2008) method, splitting trajectory into agronomic coherence phases. We considered that an integrated ESR score R affected this coherence. After delimiting the coherence phases, the next step consisted of qualifying each coherence phase according to the practices performed into technical combination.

From the surveys, we recorded 64 changes implemented by the winegrowers. Major levers included dose reduction, replacement of chemical products with biocontrol and cessation of herbicides under the row. Cluster 2 experienced a higher change in the coherence phase by predominantly redesigning their cropping systems (e.g. conversion to organic farming, ), while Cluster 3 and Cluster 1 Farms primarily implemented levers focused on gaining efficiency (e.g. progressive dose reduction).

Our study underscores that the diversity of identified pathways is associated with different implemented levers and the evolution of pesticide reduction. Further analyses are essential to identify the trade-offs between pesticide reduction and other performance indicators (yield evolution) and to characterize the risks undertaken by farmers during the agroecological transition.

References:
Gliessman, S. (2016). Transforming food systems with agroecology. Agroecology and Sustainable Food Systems, 40(3), 187‑189. https://doi.org/10.1080/21683565.2015.1130765
Fouillet, E., Delière, L., Flori, A., Rapidel, B., & Merot, A. (2023). Diversity of pesticide use trajectories during agroecological transitions in vineyards : The case of the French DEPHY network. Agricultural Systems, 210, 103725. https://doi.org/10.1016/j.agsy.2023.103725
Hill, S. B., & MacRae, R. J. (1996). Conceptual Framework for the Transition from Conv entional to Sustainable Agriculture. Journal of Sustainable Agriculture, 7(1), 81‑87. https://doi.org/10.1300/J064v07n01_07
Merot, A., Alonso Ugaglia, A., Barbier, J.-M., & Del’homme, B. (2019). Diversity of conversion strategies for organic vineyards. Agronomy for Sustainable Development, 39(2), 16. https://doi.org/10.1007/s13593-019-0560-8
Moulin, C.-H., Ingrand, S., Lasseur, J., Madelrieux, S., Napoléone, M., Pluvinage, J., Thénard, V., 2008. Comprendre et analyser les changements d’organisation et de conduite de l’élevage dans un ensemble d’exploitations : propositions méthodologiques, in: Dedieu, B., Chia, E., Leclerc, B., Moulin, C.-H., Tichit, M. (Eds.), L’élevage en mouvement. Flexibilité et adaptation des exploitations d’herbivores. Quae, p. 3.
Wezel, A., Casagrande, M., Celette, F., Vian, J.-F., Ferrer, A., & Peigné, J. (2014). Agroecological practices for sustainable agriculture. A review. Agronomy for Sustainable Development, 34 (1), 22. https://doi.org/10.1007/s13593-013-0180-

Speaker: Esther Fouillet (ABSys, Univ Montpellier, CIHEAM-IAMM, CIRAD, INRAE)

173_Fouillet.pptx

46 Yield and quality of food and feed in organic farming systems with and without livestock

Introduction
Organic farming restricts the import of fertilisers to support crop and grassland production because it aims to rely on supplying nutrients to crops through managing soil fertility via rotations and the use of on-farm manures and crop residues rather than direct intervention. Designing rotations that effectively use nitrogen fixed by legumes is challenging, as the release of fixed nitrogen through mineralisation is difficult to predict. Some import of nutrients from outside the farm is allowed but restricted via certification rules. This paper explores yield, nutrient uptake and soil fertility in contrasting stocked and stockless organic farming rotations in a long-term experiment in Scotland.
Materials & methods
A replicated experiment comparing two 6 course crop rotations with different ratios of ley to arable cropping was established at Tulloch, Aberdeen (02°15’W, 57°11’N), UK in 1991. From 1991–2006, the experiment compared two rotations, the first with 3 years of grass/white clover ley and 3 years of arable cropping (T50) and the second with 4 years of grass/white clover ley and 2 years of arable crops (T67). These rotations are described in detail in Watson et al. (2011). In 2007, T67 was changed to a stockless or “plant based” rotation (T0), with a one-year grass/red clover green manure followed by 5 years of arable cropping. The stockless rotation is described in Ball et al. (2014). Crop yield and quality, soil nutrient contents and soil organic matter have been measured over 32 years. Nutrient budgets have been calculated on a rotational basis to address relationships between yield and nutrient inputs in stocked and stockless systems. Yields have been analysed over rotational cycles.

Results
<insert Figure 1 here>

Figure 1: Yields (85% dry matter) of spring oats and spring barley with and without undersowing (u/s) of red clover (RC) or white clover (WC) in a stocked rotation with 3 years of grass/clover ley (T50) or a stockless rotation (T0) in the 4th (2008-2013) and 5th cycle (2014-2019) of the experiment.

The median yields of spring barley and spring oats declined between the 4th and 5th rotational cycle of the experiment (Figure 1) in all rotations. The decline in yield was larger in the stockless system. The median yields of organic grass/white clover year 2 in T50 and T67 declined over time. Silage yields of the 4th and 5th cycles for T50 were lower than the median yields for cycles 1–3 (data not shown). Maximum yields for the organic grass/white clover leys were 15.8, 13.3 and 10.1 t DM/ha in swards aged 2, 3 and 4 years respectively. Extractable P and K in soil has declined over time in all the rotations. Soil organic matter declined in the stockless (T0) system but did not show a clear trend in the stocked rotation (T50) (data not shown).

Discussion
The decline in cereal yields over time reflects declining levels of soil P and K. Maintaining soil P and K levels from acceptable sources is widely accepted as a challenge in systems reliant on biological N fixation. The decline in soil organic matter in the stockless (T0) system reflects the difficulties of maintaining soil organic matter in systems without grazing livestock or manure additions and is a major consideration for future production systems. Nutrient budgets provide helpful information for decision making on suitable inputs for organic systems.

1. References
   Ball B.C., Griffiths B.S., Topp C.F.E., Wheatley R., Walker, R.L., Rees R.M., Watson C.A., Gordon H., Hallett P.D., McKenzie B.M. and Nevison I.M. (2014) Seasonal nitrous oxide emissions from field soils under reduced tillage, compost application or organic farming. Agriculture, Ecosystems and Environment 189, 171–80.

Watson C.A., Baddeley J.A., Edwards A.C., Rees R.M., Walker R.L. and Topp C.F.E. (2011) Influence of ley duration on the yield and quality of the subsequent cereal crop (spring oats) in an organically managed long-term crop rotation experiment. Organic Agriculture 1, 147–159.

Speaker: Prof. Cairistiona Topp (SRUC)

273_Topp.pdf

47 Soil phosphorus budgets differ according to plot managements and farm types: a French observatory

Introduction
Soil fertility management differs significantly in organic vs. conventional farming systems, as it ideally relies on closing nutrient cycles rather than on the use of external mineral fertilisers’ inputs. While nitrogen (N) fertility is relatively easy to manage through BNF, phosphorus (P) management is more challenging (Möller et al., 2018). Therefore, investigating soil P nutrient flows and status is key to assessing the sustainability of fertilisation practices on organic farms. A number of studies have already attempted to investigate the relationship between farm-gate P budgets and farm types or management practices, with contrasting results (Reimer et al. 2020). However, there is still a knowledge gap in the factors that drive the soil P budgets of organic fields across management practices and farm types.

Methods
We analyse 5-year P budgets for 179 certified organic plots distributed over a wide range of geographical zones in France. The plots were selected to cover a range of farm types, conversion dates, pedoclimatic conditions, as well as cropping practices, in order to identify possible relationships between territorial socio-economic characteristics of farms, P management practices and soil P budgets. Semi-directive interviews were conducted to collect data for the calculation of soil P budgets. Soil budgets (Watson et al., 2002) were calculated for each surveyed plot. Soil P availability was estimated using the Olsen method. The data were analysed using a Linear Mixed Model. As few relationships were identified in the whole dataset, a Factor Analysis of Mixed Data was performed in order to identify associations between management, socio-economic and territorial variables and to analyse the similarity between the plots studied. Subsequently, Hierarchical Clustering on Principal Components was used to identify clusters of similar plots.

Results & Discussion
The data showed a wide range of socio-economic contexts, farm production types and P management strategies. Mean annual soil P budgets ranged from -32.3 to 50.3 kg.P ha-1 y-1. Over the study period, only 7% of the plots had a consistently positive soil P budget, while 30% of plots repeatedly had a negative soil P budget and the remaining 64% had either positive or negative budgets. Soil P budget were mostly explained by the cumulative P inputs, followed by P management, the frequency of N-fixing crops, and frequency of fertilisation. If the plot management was characterized by high P inputs, a high proportion of exogenous P and a low frequency of N-fixing crops, the average P budget tended to be positive. On the contrary, we found a significant negative relationship between the frequency of N-fixing crops in rotations and the P budgets, thus raising concerns about the long-term P fertility of organic farms that rely heavily on BNF. The cluster analyses revealed contrasting situations regarding P management practices and thus soil P budgets. Interestingly, the absence of livestock on the farms led to divergent situations with, on the one hand, cropland plots that were not fertilized at all and, on the other hand, plots that received important quantities of exogenous P inputs. Conversely, plots located on livestock farms tended to have more balanced soil P budgets. In conclusion, a strategic management of P resources and fertilisation is necessary to avoid soil P imbalances that may be difficult to reverse in the medium to long term. Our analysis also shows that the presence of livestock is often, although not always, correlated with a balanced management of soil P status. Thus, the reintegration of crops and livestock in organic systems has a strategic importance also for the P management, in addition to other agronomic benefits.

References
Möller, K., Oberson, A., Bünemann, E.K., Cooper, J., Friedel, J.K., Glæsner, N., Hörtenhuber, S., Løes, A.-K., Mäder, P., Meyer, G., Müller, T., Symanczik, S., Weissengruber, L., Wollmann, I., Magid, J., 2018. Chapter Four - Improved Phosphorus Recycling in Organic Farming: Navigating Between Constraints, in: Sparks, D.L. (Ed.), Advances in Agronomy. Academic Press, pp. 159–237.
Reimer, M., Möller, K., Hartmann, T.E., 2020. Meta-analysis of nutrient budgets in organic farms across Europe. Org. Agr. 10, 65–77.
Watson, C.A., Bengtsson, H., Ebbesvik, M., Lùes, A.-K., Myrbeck, A., Salomon, E., Schroder, J., Stockdale, E.A., 2002. A review of farm-scale nutrient budgets for organic farms as a tool for management of soil fertility. Soil Use and Management 18, 264–273.

Speaker: Dr Pietro Barbieri (Bordeaux Sciences Agro)

48 Sowing date and sowing rate affect yield and yield components of winter poppy

1. Introduction
   Growing spring poppy for bakery products has a long tradition in Central Europe. Mean spring poppy seed yields in Austria are with 75.0 g m-2 (2008–2017) quite low as spring poppy starts to flower late and drought during the transition from the vegetative to the generative phase can lead to significant yield reductions. Growing winter poppy instead of spring poppy might get more favorable under conditions of climate change. The recommended sowing rate for spring poppy is 100 to 150 mg m-2. The sowing rate for winter poppy might be lower as it develops larger plants. However, the knowledge on optimum sowing date and optimum sowing rate for winter poppy under Pannonian climate conditions in Central Europe is missing.
2. Materials, methods
   A two-year field experiment was performed in 2014/15 and 2015/16 in Eastern Austria in Groß-Enzersdorf, located in Marchfeld plain which belongs to the Pannonian Basin. The mean annual temperature is 10.7 °C and the mean annual precipitation is 568 mm. Four sowing dates ranged from early September to mid/end of October: SD 1 = 8 September 2014 or 8 September 2015, SD 2 = 22 September 2014 or 22 September 2015, SD 3 = 2 October 2014 or 6 October 2015, SD 4 = 13 October 2014 or 27 October 2015. The two sowing rates were 50 or 100 mg seeds m-2. Main effects for factors are shown. For interactions of factors and details for the experimental design and setup see Neugschwandtner et al. (2023).
3. Results
   The seed yield was highest by sowing in early October (Table 1). With this sowing date (SD 3), a higher number of capsules plant-1 and seeds plant-1 could be obtained although the plant density was lowest.
   The latest sowing date (SD 4) resulted in at the lowest number of capsules plant-1 and seeds plant-1. The number of seeds capsules -1 was higher in SD 3 and 4 than in SD 1 and 2. The TKW was ranked as followed among SD: 2 ≥ 3 ≥ 1 ≥ 4.
   The lower sowing rate resulted in a higher seed yield as the capsule density, number of capsules plant-1, seeds plant-1 and the TKW were higher than with the higher seeding rate. The higher seeding rate just resulted in a higher plant density.
4. Discussion
   The optimum sowing date for winter poppy under Pannonian climate conditions in Central Europe is early October but sowing can be performed over a wider range of dates. A much lower sowing rate than the recommended one for spring poppy can be used.
5. References
   Neugschwandtner R.W., Dobos G., Wagentristl H., Lošák T., Klimek-Kopyra A., Kaul H.-P., 2023. Yield and Yield Components of Winter Poppy (Papaver somniferum L.) Are Affected by Sowing Date and Sowing Rate under Pannonian Climate Conditions. Agriculture (Switzerland), 13 (5), art. no. 997.

Speaker: Prof. Reinhard Neugschwandtner (University of Natural Resources and Life Sciences, Vienna)

338_Neugschwandtner.ppt

49 Conceptual framework of a Decision Support Tool aimed at enhancing fertilization advice for agroecological banana cropping systems

Introduction

In conventional intensive banana monoculture systems, fertilization, mainly mineral-based, is managed to keep high levels of mineral elements in soil, in order to ensure maximal crop nutrition and compensate for leaching losses. It actually results in excessive applications of fertilizers, far surpassing plant’s uptake and soil absorption capacity (Godefroy & Dormoy, 1983).
With the development of agroecological banana cropping systems in French West Indies (FWI), adjusting fertilization to plant’s requirements in order to reduce nutriment losses by leaching became a priority. But these new banana cropping systems, based on increasing use of organic fertilizers and cover crops in association with bananas could show nutritional stresses for crop. To prevent them, the nutritional status of crop is typically assessed through chemical leaf analysis, it allows a prompt correction of deficiencies. However, this method is not easy to use because it doesn’t take into account N dilution with biomass growth (Lemaire et al., 1984). Furthermore, long-term management by soil nutrition is crucial to ensure fertility, although soil diversity in the French West Indies with different exchanges capacity complicates even more this management.

The management of fertilization in the new banana cropping systems, more complex, requires the design of new decision support tools in order to adjust the inputs of fertilizers dynamically based on plant nutritional status and soil resources availability. Here, we present a conceptual framework of a Decision Support Tool designed to assist agricultural advisory in fertilization management of banana cropping systems in the French West Indies.

Materials and Methods

The conceptual framework of the decision support tool has been realized in three steps:
1. A literature review of plant and soil nutritional status diagnostic methods.
2. A detailed analysis of recommendations for fertilization of banana cropping systems through interviews between farmers and private agricultural advisor during three days. This step enabled the identification of limits on actual method and expectations for the new tool.
3. Designing conceptual framework of the decision support tool for fertilization management and identification of needs of data for parameterization.

Results

Three methods are used for analyze nutrient soil availability: Sufficiency Level of Available Nutrients (SLAN), also called “Critical Tresholds Method”, Basic Cation Saturation Ratio (BCSR) or “ideal soil” suggested a balanced soil cation ratios for optimal plant growth and Nitrogen Balance method.
Concerning foliar diagnostic, three methods are used: Critical Values Approach (CVA) that compared nutrient levels to individual thresholds, Diagnostic and Recommendation Integrated System (DRIS norm) that used ratios of two nutrients and Compositional Nutrient Diagnosis (CND) that allows to compare ratios of one nutrient to the levels of all other nutrients.

Current fertilization strategy was reviewed, and leaf and soil analysis were analyzed using CVA method for foliar diagnostic and SLAN method for nutrient soil availability. References of norms used and threshold associated are sometimes unknown or seems very old (1990’s). The introduction of cover crop in system was never considered.

Figure 1 illustrates that fertilization management for agroecological banana cropping systems should carried out on two distinct compartments (soil and plant) for taken into account the both tactical - short term and strategic - long term management.

Figure 1 : Conceptual framework of a Decision Support Tool for fertilization management in banana cropping system.

Discussion

The conceptual framework realized in this study presents an innovative Decision Support Tool, able to assist farmers for fertilization management by combining tactical and strategical management. This dual approach, taking into account both long-term requirements linked to soil fertility and immediate adjustments to correct deficiencies will allow dynamic and sustainable management of soil fertility of agroecological banana cropping systems in FWI.

References

Godefroy, J., & Dormoy, M. (1983). Dynamique des éléments fertilisants dans les sols des bananeraies martiniquaises. Fruits, 38, 451‑459.
Lemaire, G., Salette, J., Sigogne, M., & Terrasson, J.-P. (1984). Relation entre dynamique de croissance et dynamique de prélèvement d’azote pour un peuplement de graminées fourragères. I. —Etude de l’effet du milieu. Agronomie, 4(5), 423‑430.

Speaker: Mrs Julie Barret (1. CIRAD, UPR GECO, F-97130 Capesterre-Belle-Eau, Guadeloupe, France 2. GECO, Univ Montpellier, CIRAD, Montpellier, France 3. SCIC Martinique SAS, F-97200 Fort-de-France, Martinique, France)

50 The impact of pH and climate on the yield of cereals

Introduction
It is well known that the pH of soils will impact on the yield of the crop, and the optimum pH for grasslands is around 6.0 while for arable crops the optimum pH is 6.5. Soil pH is usually tested and modified periodically with lime application to raise the pH as crop growth and associated management practices generally tend to reduce the pH over time. To demonstrate the value of liming, a pH experiment was established at SRUC Craibstone, Aberdeen (02°15’W, 57°11’N) in 1961. The trial was established as a demonstration with a gradient from 4.5 to 7.5. The aim of this study was to assess the yield sensitivity of spring oats and winter wheat to meteorological variables.
Methodology
The rotation established in 1961 was an 8-course ley-arable system. The pH of the plots was tested annually and amended as appropriate in order to maintain the target pH. The rotation included three years of grass/white clover, winter wheat, potatoes, spring barley, swedes and undersown spring oats. Although every course of the rotation is present in every year, there are no within year replicates. The fertiliser applications have not changed since the establishment of the trial, and crop protections products were applied when required.
The yield data is reliable from 1969, and by that time the soils had settled at or close to the target pH. Currently, we have focused on exploring the effect of the pH on the yield of the oats and the wheat over the last 50 years. This has been carried out as a two-stage process. The first stage was to fit separately for each year a gaussian non-linear curve (Archontoulis & Miguez, 2015) to the yield data. Thus the equation fitted was:
yield = (w.max * exp(-0.5((pH-pHm)/b)*2)
w.max is the maximum yield, pHm represents the pH at this maximum yield, and b controls the width of the bell. The initial value for w.max was set at the average maximum yield over the course of the trial, and the pHm was set at the pH at which that yield occurred. The initial value of b was set at 1. The next stage was to explain the estimated w.max values by the weather parameters. The weather variables selected to include in the regression analysis were based on total precipitation and average daily temperature during both the previous winter, and the current growing season. In addition, variables based on rainfall and temperature were calculated to assess whether extreme weather conditions during the growing season were impacting on yield. These included the mean maximum temperature (TDD), the maximum number of dry days (rainfall < 0.2 mm (CDD), the maximum number of days where the rainfall was greater than 0.2 mm (CRD) and the maximum number of days where then rainfall was greater than 1mm (CHD). All the weather parameters were also squared to include any non-linear effects. A stepwise regression was performed to determine which of the climatic variables were impacting the w.max parameter.
Results
The peak maximum yield for the spring oats and winter wheat occurred at a pH5 and 5.5, respectively. The results indicate that for oats w.max was explained by average daily temperature (T), winter rainfall (WP), and the extreme conditions of the maximum average daily temperature (TDD), and the maximum number of dry days (CDD). A wider range of weather parameters has a significant impact on the w.max for winter wheat. In this case, average daily temperature (T, T2), and total rainfall during the winter and the growing season (P, P2) were significant. The extreme conditions of the maximum average daily temperature (TDD, TDD2), the maximum number of rain days (CHD, CRD).
Discussion
This long-term pH experiment has enabled us to explore the effect of pH on yield over an extended period. Temperature, rainfall and extremes of temperature and rainfall are important in determining the maximum yield of the spring oats and winter wheat. However, the maximum for winter wheat was affected by the number of rainy days whereas spring oats was affected by the number of dry days.
References
Archontoulis, S. V., & Miguez, F. E. (2015). Nonlinear Regression Models and Applications in Agricultural Research. Agronomy Journal, 107(2), 786–798. https://doi.org/10.2134/AGRONJ2012.0506

Speaker: Kairsty Topp (SRUC)

323_Topp.pdf

Wednesday, August 28

Reconciling short- and long-term goals in agrifood systems: what role for agricultural sciences? - Guillaume Martin

Convener: Evelin Loit-Harro

ESA2024_keynote_Martin.pdf

51 Reconciling short- and long-term goals in agrifood systems: what role for agricultural sciences?

Speaker: Guillaume Martin (INRAE)

ESA2024_keynote_Martin.pdf

Diversification in crop production

Conveners: Fred Stoddard, Tao Song

52 Synergies between short and long-term actions to promote crop diversification

1. Introduction
There is an urgent need to redesign cropping systems with the challenge to maintain high productivity, reduce inputs and their associated environmental impacts as well as mitigate climate change. Crop diversification is a key lever to meet this challenge. It means increasing the diversity of crops in time and space using strategies such as rotation extension, multiple cropping, intercropping, and/or a combination of these practices. However, the diversification of cropping systems is limited due to barriers occurring at the farm level, along value chains as well as in the coordination between actors and institutional rules. Based on a European network of field experiments on crop diversification (Project H2020 DiverIMPACTS), this paper aims to demonstrate the need to increase synergies between short- and long-term actions to promote crop diversification.

2. Materials and Methods
We studied the combination of temporal and spatial diversification in a network of field experiments (10 sites, 7 countries). We assessed the benefits and risks of crop diversification during a three-year cropping period and we identified the ingredients for a successful diversification. We considered not only the final performances of the crop sequences but also the trajectories, as well as the adaptation needed all along the dynamics of crop diversification.

3. Results

Designing diversified cropping systems leading to rapid and successful results
Crop diversification did not always lead to positive effects on all sustainability dimensions. However, our results showed that regardless of the starting point and the type of agricultural systems (conventional or organic), it is possible to design innovative crop sequences which relatively quickly, i.e. in a 3 year crop sequence, combined higher energy yields, higher gross margins, reduced fertilizer and pesticide use and reduced greenhouse gas emissions, than their respective reference. Through these “successful” sequences, we identified specific rules, or ingredients to increase the benefits and avoid trade-offs (figure 1).

Having a strong goal of sustainability and resilience with a long-term perspective while adapting continuously the system to face different risks
Diversification is an evolving process with many adaptations needed all along the trajectory due to different sources of uncertainty. Climatic conditions (mainly water conditions) and biotic factors (mainly weeds) were key sources of uncertainty requiring different adaptations in crop sequences. The designed systems and their management were also influenced by the available knowledge. The insertion of a new crop or a new strategy requires technical skills that are mastered progressively. External factors also influence the dynamic process such as opportunities of new markets, evolutions in regulations and climate change. Adapting continuously the diversification process, i.e., crops and practices, is required, to face these different sources of uncertainty.

Assessing ex ante the benefits and risks to help the design of relevant cropping sequences and monitoring continuously the system
We designed a new tool (Keichinger et al., 2021) based on a set of indicators assessing temporal and spatial diversity of a crop sequence. Such an indicator helps the prediction of the ecosystem services provided by a crop sequence and the potential trade-offs to support various actors in their decision-making. An example was given for crop sequences rich in legumes that decrease the use of mineral but increases the risk of diseases. Moreover, we observed that monitoring is key to be reactive to consider how the crops and the whole system evolve. The lessons learnt from monitoring are used to adapt and improve the management in an iterative process both with a short term and long-term perspective.

The need to complexify cropping systems temporarily while removing other barriers at other scales in a longer-term perspective.
Increasing the intensity of diversification in time and space can be perceived as a complex process for farmers or advisers. However, we consider that the complexity will be easier to cope with if innovations are designed at other scales: selection of minor crops to improve their performance relatively to dominant species, design of new value-chains solving machine-related problems, new regulations, and undoubtedly agricultural policies promoting crop diversification.

References

Keichinger, O., Viguier, L., Corre-Hellou, G., Messéan, A., Angevin, F., Bockstaller, C. (2021). Un indicateur évaluant la diversité globale des rotations : de la diversité des cultures aux services écosystémiques. Agronomie, environnement & sociétés 11, 19p. https://agronomie.asso.fr/aes-11-1-17

Speaker: Guénaëlle Corre-Hellou (USC LEVA (ESA-INRAE))

53 The productive performance of intercropping

Agricultural diversification is useful for agronomic, environmental, and dietary reasons, but its consequences for productivity are debated. We conducted a global meta-analysis of 226 field trials, and found (as previous meta-analyses did) that intercropping, i.e. species mixture, leads to substantial land savings over single crops when the objective is to produce a diversified set of crop products. However, if the objective of production is to maximize grain caloric output from the field, intercropping leads on average to a small yield penalty of 4% compared to the most productive single crop species comprised in the mixture, often maize. On the other hand, intercrops provide similar or greater protein yield than the most protein-productive sole crop in the mixture, especially with modest N fertilizer application. In addition, intercropping provides further ecological services, such as pest and disease control, and improved nutrient cycling. Such intercropping advantages have potential to mitigate the environmental footprint of farming and make cropping systems more sustainable. But we should not expect that in general intercrops will outperform the most productive sole crop that may be grown on a parcel of land. Results were published in the Proceedings of the National Academy of Sciences in early 2023. The presentation will present results of this study in the context of other and earlier meta-analyses, showing that the choice of metric has a critical influence on the conclusions that may be drawn from a meta-analysis or any intercropping study.

Li CJ, Stomph T-J, Makowski D, Li HG, Zhang CC, Zhang FS, van der Werf W (2023) The productive performance of intercropping. Proceedings of the National Academy of Sciences of the United States of America 120(2): e2201886120. https://doi.org/10.1073/pnas.2201886120

Speaker: Wopke van der Werf (Wageningen University)

65_van der Werf wide 2024-08-25.pptx

54 Silvopastoral systems interact with management practices and contribute to mitigate N losses from dairy farms: a case in Brittany, France

Nitrogen (N) losses from agroecosystems threatens the environment. Regions with high livestock densities, such as Brittany (France), are particularly sensitive to this issue. In addition, N losses are expected to increase under the rising intensity and frequency of extreme weather events. Silvopastoral systems, i.e., combination of trees and pastures, are a promising solution to prevent N losses in the short- and long-term. If recent studies highlighted the potential of silvopastures to limit N losses in the close vicinity of trees (e.g., (Zhu et al. 2020), their contribution remains ambiguous at farm and territory level.

This study aims to disentangle the relations between silvopastoral systems and the regulation of N losses by assessing the farm-gate N balance (FGB; kg N ha-1 yr-1) in a gradient of dairy farms of Brittany that either maintained and/or planted hedges and alley-cropping silvopastures. We hypothesized that the farms which adopted silvopastures the most would present lower N surplus due to (i) direct impact of the presence of trees, and (ii) the adoption of farming systems with low N inputs.

Thirty-three farms were surveyed and modelled in order to assess their FGB as a proxy for risk of N losses. FGB was calculated as the difference between N inputs and outputs; with inputs including N from fertilizers, biological N fixation, atmospheric depositions, soil N fixation by free living soil organisms, animal feed, and litter; and outputs including N from exported crops, animal products, manure, and wood. Farms were then classified through hierarchical clustering based on variables of N inputs, outputs, FGB and surface planted with trees. Variation partitioning of the FGB was performed in order to disentangle the impact of trees as compared to the impact of the management of N inputs and outputs.

The variation partitioning revealed that N inputs alone contributed the most to explain the variation of FGB (55.6%), while tree variables alone did not explain its variation. Yet, these latter contributed to explain the variability of FGB when considering their interaction with practices on N inputs (8.0%) and both N inputs and outputs (15.3%). Furthermore, the hierarchical clustering resulted in four clusters with a gradient of farming systems from extensive farming systems with high plantation of silvopastoral systems and low N surplus to intensive farming systems based on high external N inputs and maintaining old hedges.

Our results suggested that the adoption of silvopastoral systems was not in itself a major lever to limit N losses. Yet, synergies between the adoption of silvopastures and the management of N inputs led to lower N surplus at farm scale (e.g. no fertilization on the areas planted with trees). The adoption of further practices would enhance the positive impact of silvopastoral systems on the limitation of N losses (Komainda et al. 2023; Papanastasis et al. 2008). Moreover, farmers that adopted silvopastures favored the stability of N-related processes towards extreme climates events through the use of organic fertilization and the plantations of trees (Mettauer et al, in prep). The conception of silvopastoral systems that take further advantages from the synergies between presence of trees and regulation of N inputs (e.g., reduction of fertilizers inputs next to the trees or use of tree branches as fodder; (Komainda et al. 2023; Papanastasis et al. 2008)) is promising way to limit N losses in the short- and the long-term for regions with high livestock densities.

References :
Komainda, Martin, Rahel Sutterlütti, Manfred Kayser, and Johannes Isselstein. 2023. « Adjusting Nitrogen Fertilization to Spatial Variations in Growth Conditions in Silvopastoral Systems for Improved Nitrogen Use Efficiency ». Nutrient Cycling in Agroecosystems, novembre. https://doi.org/10.1007/s10705-023-10317-6.
Papanastasis, V. P., M. D. Yiakoulaki, M. Decandia, and O. Dini-Papanastasi. 2008. « Integrating woody species into livestock feeding in the Mediterranean areas of Europe ». Animal Feed Science and Technology 140 (1): 1‑17. https://doi.org/10.1016/j.anifeedsci.2007.03.012.
Zhu, Xiai, Wenjie Liu, Jin Chen, L. Adrian Bruijnzeel, Zhun Mao, Xiaodong Yang, Rémi Cardinael, et al. 2020. « Reductions in Water, Soil and Nutrient Losses and Pesticide Pollution in Agroforestry Practices: A Review of Evidence and Processes ». Plant and Soil 453 (1): 45‑86. https://doi.org/10.1007/s11104-019-04377-3.

Speaker: Ms Romane METTAUER (UMR SAS, Institut Agro Rennes-Angers, INRAE)

96_Mettauer.pdf

55 Unravelling the diversity of technical operations in diversified perennial-based cropping systems: the case of smallholder immature rubber intercropped with pineapple in Rayong, Thailand

1. Introduction
   Diversification practices in perennial-based cropping systems (e.g. agroforestry, intercropping, etc.) are promoted for their global positive effects on the agroecosystems’ performances at the plot scale (Beillouin et al., 2019). In Thailand, intercropping with various crops is often adopted in smallholder rubber plantations during the first four years, to cope with the challenges of the immature period. In the literature, these cropping systems are usually characterized by describing the crop choice in the inter-rows only, without considering the associated technical operations (Simon et al., 2024). This study aims at (1) characterizing thoroughly the diversity of technical operations applied to intercrops and rubber trees and; (2) understanding the relationships between the managements of intercrops and rubber trees.

2. Materials and methods
   We conducted interviews in Rayong province, Thailand, with 24 farmers that had at least one rubber plantation between 1- and 4 years old, intercropped with pineapple. All the technical operations applied on pineapple and rubber trees respectively were recorded on a timeline. The "Typ-iti” method (Renaud-Gentié et al., 2014), combining multivariate analysis, clustering and association rules, was used to explore the diversity of technical management routes (TMRs) adopted on pineapple. The technical operations applied to rubber trees were compared with pineapple management clusters through mixed linear models to analyze possible relationships between managements in the inter-rows and rubber rows.

3. Results
   Regarding pineapple management, three initial clusters were observed based on TMR from the soil preparation to the first harvest. Clusters 1 and 2 were constituted of 11 and 8 TMRs respectively, implemented by farmers producing pineapple for industries. They were both characterized by the use of fruit crowns as planting material and an intensive flower induction, but differing in terms of chemical fertilization and weeding. Cluster 3 was constituted of six TMRs, implemented by farmers producing pineapple for local markets, and was characterized by the use of plant suckers as planting material only, with less chemical products used compared to Clusters 1 and 2. A last cluster, named Cluster 4, consisted of TMRs implemented by all farmers, spanning from the first harvest to the second, and was distinguished by a decrease in chemical inputs. A diversity of technical operations was also observed on rubber trees, particularly in the frequency of chemical fertilizer applications, the frequency of weeding operations and the weeding methods used. However, the differences in technical operations applied to rubber trees were not linked to the pineapple management.

4. Discussion
   This study highlights the large diversity of technical operations in rubber + pineapple immature plantations. Contrary to expectations and in contrast to what was observed in other perennial cropping systems (Koussihouèdé et al., 2020), pineapple and rubber trees are managed independently. More globally, our results underline the need to not only consider the crop choice but also the possible diversity of technical operations and the plot level strategies of farmers to better understand the variability of performances in a multicriteria assessment (Perrin et al., 2023).

5. References
   Beillouin, D., Ben Ari, T., Makowski, D., 2019. Evidence map of crop diversification strategies at the global scale. Environmental Research Letters 14, 123001. https://doi.org/10.1088/1748-9326/ab4449
   Côte, F.X., Rapidel, B., Sourisseau, J.M., Affholder, F., Andrieu, N., Bessou, C., Caron, P., Deguine, J.-P., Faure, G., Hainzelin, E., Malezieux, E., Poirier-Magona, E., Roudier, P., Scopel, E., Tixier, P., Toillier, A., Perret, S., 2022. Levers for the agroecological transition of tropical agriculture. Agron. Sustain. Dev. 42, 67. https://doi.org/10.1007/s13593-022-00799-z
   Koussihouèdé, H., Clermont-Dauphin, C., Aholoukpè, H., Barthès, B., Chapuis-Lardy, L., Jassogne, L., Amadji, G., 2020. Diversity and socio-economic aspects of oil palm agroforestry systems on the Allada plateau, southern Benin. Agroforest Syst 94, 41–56. https://doi.org/10.1007/s10457-019-00360-0
   Perrin, A., Yannou-Le Bris, G., Angevin, F., Pénicaud, C., 2023. Sustainability assessment in innovation design processes: place, role, and conditions of use in agrifood systems. A review. Agron. Sustain. Dev. 43, 10. https://doi.org/10.1007/s13593-022-00860-x
   Renaud-Gentié, C., Burgos, S., Benoît, M., 2014. Choosing the most representative technical management routes within diverse management practices: Application to vineyards in the Loire Valley for environmental and quality assessment. European Journal of Agronomy 56, 19–36. https://doi.org/10.1016/j.eja.2014.03.002
   Simon, C., Thoumazeau, A., Chambon, B., Sajjaphan, K., Metay, A., 2024. Diversity, adoption and performances of inter-row management practices in immature rubber plantations. A review. Agron. Sustain. Dev. 44, 12. https://doi.org/10.1007/s13593-024-00944-w

Speaker: Charlotte Simon (CIRAD)

56 Provision of ecosystem services by biodiversity-based cropping systems in the context of climate change: a 50-year simulation in western France

Introduction.
Biodiversity-based cropping systems are a promising option for agriculture to meet socio-environmental issues under climate change. Yet, the levers that could be employed to establish a system based on biodiversity, such as crop diversification, require a degree of coordination with the underlying agroecosystem processes and the specific requirements of farmers. The long-term impacts of diversified systems are particularly challenging because design and assessment methods are not yet adapted. We hypothesized that crop models, combined with other tools, can be used to assess the impacts of biodiversity-based cropping systems on the provision and stability of ecosystem services over time. In this way, we implemented a disruptive crop succession with the STICS model (Brisson et al., 2003) version 10.0.0)and estimated the long-term (50-year) trade-offs between the ecosystems services of this biodiversity-based cropping system in a temperate oceanic region.

Materials and Methods.
The STICS model was used to simulate the long-term effects of a biodiversity-based cropping system on three variables: (i) the annual quantity of nitrates resulting from mineralisation in the topsoil (0-60 cm), (ii) the annual quantity of nitrates leached (beyond the sol depth measuring 110cm) and (iii) the annual soil organic carbon stock. These variables represent two regulating ecosystem services: regulation of soil quality and regulation of water quality.
The topsoil characteristics were as follows: 18.8% of clay; pH of 5.9; organic matter content of 2.8%. Historical climate data (1973-2023) from SAFRAN model and DRIAS projection data (2023-2073) were used for two IPCC climate scenarios (representative concentration pathways (RCP) 4.5 and 8.5).
The biodiversity-based cropping system was co-designed through two participatory workshops with local experts (two farmers, two technicians and one researcher). The resulting cropping system comprised 16 crop species (eight cash crops and eight service plants) over a six-year period. In order to facilitate comparison, two additional cropping systems were virtually implemented: a conventional two-species rotation (corn-wheat) that is commonly found in western France, and an agroecological diversified rotation that was recently tested in western France. The simulations were conducted over a 50-year period, with three different climate scenarios considered: the past climate (1973-2023), and scenarios RCP 4.5 and 8.5 (both 2023 to 2073). The evolution of variables was then analysed through time series statistics, using the R software (version 4.3.3). A functional principal component analysis was conducted to characterise each series and to identify temporal patterns. Subsequently, a linear regression model with time interaction was employed to compare the consequences of the biodiversity-based cropping system vs. the two additional systems, for each period.

Results.
The results are still being compiled and statistically analysed. Nevertheless, preliminary findings indicate that the annual quantity of nitrates resulting from mineralisation is higher in the soil where the biodiversity-based cropping system is implemented compared to the two additional systems. One possible explanation for this phenomenon is the supply of N-rich residues by leguminous plants introduced through the biodiversity-based cropping system. However, the higher quantity of nitrates resulting from mineralisation in the biodiversity-based cropping systems is also accompanied by more frequent nitrates leaching events. The soil organic carbon stock decreases in all three situations, but the biodiversity-based cropping system reaches balance earlier than both additional systems, with a higher balance value. These results indicate a positive evolution of the regulation of soil quality service over time for the biodiversity-based cropping system, while the regulation of water quality service deteriorates due to increased nitrate leaching compared to the other systems. The subsequent phase of this research will involve the study of additional variables to assess the contribution of biodiversity-based cropping systems on the provision of other ecosystem services and their stability over time (e.g. crop yields for the provisioning service, greenhouse gas emissions for climate regulation).

Reference.
Brisson, N., Gary, C., Justes, E., Roche, R., Mary, B., Ripoche, D., Zimmer, D., Sierra, J., Bertuzzi, P., Burger, P., 2003. An overview of the crop model STICS. European Journal of agronomy 18, 309-332.

Speaker: Arnaud DELBAERE (Phd Student)

ESA_327_DELBAERE.pptx

Improving ecosystem services in agroecosystems

Conveners: Laura Stefan, Louise Blanc

57 Overview of France 2030 interdisciplinary research programs on the agroecological transition

Introduction. Global climate change requires that the agriculture sector adapts and mitigate its impacts. The present awareness that six of the nine planetary boundaries have already been exceeded implies that agricultural and food systems reconcile with the environment from which they get natural resources that are depleting (e.g., soil, biodiversity) or whose access is becoming irregular and competitive (e.g., water). Agroecology refers to ecologically and socially responsible agricultural practices that link agronomy and ecology. There are practices that rely on the functionalities offered by diversity and interactions within and across ecosystems with the aim of reducing pressure on the environment and the use of inputs, preserving natural resources (air, water, soil, biodiversity) and reducing the work load and complexity. The agroecological transition takes place in the context of rapidly changing conditions that impact agricultural production: climate change and in particular the increasing frequency of extreme events (drought, floods, temperature variations such as heat waves, cold or frost, etc.), changing consumer demands in terms of naturalness. The government roadmap “France 2030” aims at enhancing innovation in various sectors in France, and has identified the agroecological transition among its top priorities.
Methods. Public and private stakeholders together with scientists from various agricultural sectors and disciplines (agronomy, genetics, data sciences, social sciences, etc.) elaborated a national acceleration strategy referred to as SADEA for “Sustainable agricultural systems and agricultural equipment contributing to the ecological transition”, as part of the France 2030 roadmap.
Results. Three large-scale programs have started and support research and infrastructure projects on three complementary themes that contribute to SADEA. The program “Growing and Protecting crops Differently” (2019-2026) aims at finding new crop protection strategies for an alternative to pesticides. The program “Agroecology and ICT” (2023-2031) aims at promoting ICT as a lever for agroecology with four axes that include: 1) Shaping a socio-ecosystem conducive to responsible research and innovation; 2) Characterizing genetic resources to assess their potential for agroecology; 3) Conceiving new generations of agricultural equipment; 4) Developing digital tools and methods for data processing in agriculture, agricultural equipment and decision support. The program “Advanced plant breeding” (2023-2031) focuses on evaluating the potential contribution of plant genome editing (excluding transgenesis) as a complement to current selection tools to rapidly make available a wider range of plant varieties that respond to current and future conditions, in order to meet the urgent challenges facing agriculture (reduction in pesticide use, limited access to natural resources, water scarcity). This program focuses on the genome editing on a panel of agricultural species and agroecological traits, the introduction of genome editing into breeding schemes, and identification of the socio-economic and regulatory dynamics around genome editing. Up to now a total of 27 5- or 6-years projects have been launched by the three programs (see references for internet links).
Discussion. Drawing desirable and sustainable agriculture systems by considering the non-negotiable environmental constraints is an interdisciplinary and intersectoral challenge that needs to identify disruptive solutions and to run exploratory research based on sound scientific knowledge. SADEA provides an unprecedented research framework to address issues at the forefront of science that will provide results reducing knowledge gaps and promoting innovative solutions. Collaborations are main avenues to be elaborated by joining public and private actors and by fostering partnerships at European and worldwide levels
References: https://www.cultiver-proteger-autrement.fr; https://www.pepr-agroeconum.fr/pepr-agroeconum-eng/funded-projects; https://www.pepr-selection-vegetale.fr/les-projets-de-recherche/les-projets-cibles

Speaker: Dr Claire Rogel-Gaillard (Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350 Jouy-en-Josas, France)

58 Reintegrating livestock onto crop farms: a step towards sustainability?

In Europe, the specialisation of farms and regions and the disconnection of crop and livestock productions led to major environmental externalities (Lemaire et al., 2014) Still, high-input specialized farming systems are continuing to be developed. Bucking this trend, a few pioneering farmers have intentionally reintegrated (i.e. organized the return of) livestock into crop farms in several regions. While reintegrating livestock is often depicted as sustainable, research has rarely examined these systems.

We aimed to assess the practice changes related to livestock reintegration on crop farms and their agroenvironmental impacts.

Following innovation-tracking principles (Salembier et al., 2021), we identified 19 crop farmers having reintegrated livestock in two regions where crop farming predominates: the Toulouse Basin and the Parisian Basin. Farmers’ profiles varied in production mode, farm size, crop and livestock species produced, and in the type and duration of livestock reintegration. We conducted interviews to characterize the changes of practice following livestock reintegration and assess their impacts on direct and indirect energy consumption, net greenhouse gas emissions and nitrogen balance (Zahm et al., 2019). All agroenvironmental indicators were calculated at the farm level on a yearly basis, and assessed before and after livestock reintegration.

Data analysis is still in progress, but first results (9 out of 19 farms) show that on 4 farms having reintegrated meat sheep in outdoor systems, either by buying animals or through a partnership with a shepherd, farm nitrogen balance decreased (-0.5 ± 0.3 kgN/ha on average), mostly due to nitrogen exported via meat production and, in one case, to reduced use of nitrogen fertilizers allowed by the availability of sheep manure. Energy consumption also decreased (-92 ± 48 MJ/ha), as grazing helped terminating cover crops and reducing mowing in vineyards and orchard inter-rows. When related to the farm utilized agricultural area, net greenhouse gas emissions were almost not impacted (+ 0.02 ± 0.02 teq CO2/ha) by the return of livestock, as either few sheep were reintegrated, and/or they were present on the farm for a short period of the year. The slight increase was due to livestock-related emissions, which more than compensated the emissions saved by reducing mechanized operations. This was less true in cases of increased area of pasture or grass grown in orchard or vineyard. On the contrary, for the 5 cases of on-farm poultry reintegration, farm nitrogen balance, energy consumption and net greenhouse gas emissions increased (respectively + 3.5 ± 6.2 kgN/ha, + 20 230 ± 18 605 MJ/ha and + 0.13 ± 0.2 teq CO2/ha), mostly due to high levels of feed inputs (accounting for increases by 93 ± 3% and 81 ± 8% of energy consumption and net greenhouse gas emissions respectively). The fertilization strategy was rarely adjusted according to poultry manure produced on-farm, due to a lack of knowledge on its fertilizing effect. Carbon sequestration associated with converting a crop field into a grass field planted with hedgerows and trees for free-range poultry was more than outreached by indirect emissions from feed inputs.

This study is the first to assess the agroenvironmental impact of reintegrating livestock into specialised crop farms. According to the practice changes implemented, reintegrating livestock can help promote farm resilience by decreasing its reliance on non-renewable resources, through reduced energy consumption and on-farm production of organic fertilisers. This work contributes to produce knowledge on the agroenvironmental benefits of reintegrating livestock into crop farms, which are often advocated in research studies in analogy with integrated crop-livestock systems, but are rarely confronted to data collected on farms.

References

Lemaire, G., Franzluebbers, A., Carvalho, P.C. de F., Dedieu, B., 2014. Integrated crop-livestock systems: Strategies to achieve synergy between agricultural production and environmental quality. Agric. Ecosyst. Environ. 190, 4–8. https://doi.org/10.1016/j.agee.2013.08.009
Salembier, C., Segrestin, B., Weil, B., Jeuffroy, M., Cadoux, S., 2021. A theoretical framework for tracking farmers ’ innovations to support farming system design. Agron. Sustain. Dev. 41:61. https://doi.org/10.1007/s13593-021-00713-z
Zahm, F., Alonso Ugaglia, A., Barbier, J.M., Boureau, H., Del’Homme, B., Gafsi, M., Gasselin, P., Girard, S., Guichard, L., Loyce, C., Manneville, V., Menet, A., Redlingshöfer, B., 2019. Assessing the sustainability of farms. the IDEA v4 method, a conceptual framework based on the dimensions and properties of sustainability. Cah. Agric. 28. https://doi.org/10.1051/cagri/2019004

Speaker: Clémentine Meunier (INRAE UMR AGIR)

49_Meunier.pptx

59 Beyond organic vs. conventional system dichotomy: importance of management practices in driving agroecosystem multifunctionality

Introduction

Given the backdrop of global climate change, the biodiversity crisis and the energy transition, agriculture must transition from intensive to multifunctional management (Wittwer et al., 2021). Multifunctionality refers to the ability of ecosystems to simultaneously perform multiple functions, thus ensuring the delivery of diverse ecosystem services important for human well-being (Stürck and Verburg, 2017). Agroecosystem multifunctionality studies comparing organic and conventional systems yielded controversial results that could be explained by differences in management practices. Indeed, current knowledge is particularly limited regarding how cropping systems and individual management practices might modulate agroecosystem multifunctionality (Wittwer et al., 2021). This study analyzed how management practices affect agroecosystem multifunctionality and, trade-offs and synergies among underlying functions. We considered three management practice description levels: (i) farming system (i.e. organic vs. conventional), (ii) combination of management practices that defines a cropping system, and (iii) individual management practices.

Material and methods

We measured 14 primary variables, used as proxies for seven functions, in 20 conventional and 20 organic winter cereal fields in Brittany, northwestern France. We evaluated biodiversity conservation by considering species richness of carabids, flower-visiting insects and weeds. Predation was quantified by measuring the abundance of pest natural enemies including carabids, spiders, staphylinids, ladybird larvae, and aphidophagous hoverflies. Pest colonization consisted of the abundance of two main pests of cereal fields: aphids and troublesome weeds. Pollination was estimated through the abundance of flower-visiting insects. Food and feed production was quantified using yield (quantity of products per hectare). Quality of life at work was based on the number of working hours in the field. Lastly, income contribution was assessed using costs (labor according to materials used and inputs) and sales of crop production. Generalized Linear Mixed effect Models (GLMMs) were built to assess the effects of management practices on multifunctionality index and each function. Trade-offs and synergies between functions were assessed through Pearson correlations.

Results

Multifunctionality did not differ between organic and conventional systems. We found a strong trade-off between functions related to ecological performance and socio-economic performance, especially between biodiversity conservation and food and feed production. Organic systems tended to minimize this trade-off. Our study also revealed great variability in multifunctionality among cropping systems (N = 5) and within each cropping system type. The number of soil interventions and nutrient inputs were the main drivers of agroecosystem multifunctionality and its underlying functions.

Discussion

Although organic management did not increase multifunctionality, it was beneficial to biodiversity-based functions, likely due to the absence of applied chemical products. Some cropping systems had similar multifunctionality index value but none maximized both food and feed production and biodiversity-based functions. This suggests that multifunctionality may be achievable via different management paths, allowing farmers to choose the strategies most adapted to the particular objectives and constraints of their farm (e.g. pedoclimatic conditions, farm machinery, workload). Exploring the effects of individual management practices, we found that the number of field interventions and the fertilization amount are the main determinants of cropping system performance. Logically, fields that require numerous interventions to limit the proliferation of weeds, through mechanical weeding or more frequent application of herbicides, are also those placing greater labor costs on farmers.

We thus demonstrated that beyond the organic vs. conventional system dichotomy, combinations of management practices (i.e. cropping systems) as well as individual management practices can explain the ecological and socio-economic performance of agroecosystems. In addition, we showed that specific management practices, such as reducing within-field interventions and fertilization amount, could be integrated even in conventional cropping systems to improve agroecosystem multifunctionality.

References

Gong, S., et al. (2022). Biodiversity and yield trade‐offs for organic farming. Ecology letters, 25(7), 1699-1710. https://doi.org/10.1111/ele.14017
Stürck, J., & Verburg, P. H. (2017). Multifunctionality at what scale? A landscape multifunctionality assessment for the European Union under conditions of land use change. Landscape Ecology, 32, 481–500. https://doi.org/10.1007/s10980-016-0459-6
Wittwer, R. A., et al. (2021). Organic and conservation agriculture promote ecosystem multifunctionality. Science Advances, 7(34), eabg6995. https://doi.org/10.1126/sciadv.abg6995

Speaker: Audrey Alignier (INRAE UMR 0980 BAGAP)

284_Alignier.pdf

284_Alignier.pptx

60 Relationship between agrobiodiversity, farming practices, and cocoa health perception by organic and conventional farmers in Côte d'Ivoire

Until recently, the health of cultivated plants has been approached through "pathogenic" approaches, focusing on chemical control methods against pests. To accelerate the agroecological transition, a paradigm shift is required with "salutogenic" approaches (Döring et al., 2012). These new approaches aim to better understand the natural mechanisms of pest regulation, in order to maintain plant health without using chemical products. Within cocoa-based agroforestry systems (AFS), there is a wide gradient of agrobiodiversity varying in terms of species diversity, planting density, and spatial distribution of plants (Vroh et al., 2019). Moreover, these AFS are managed by farmers who implement distinct farming practices based on knowledge and beliefs rooted in cultural, academic, and experiential heritage (Toffolini et al., 2016). This agrobiodiversity and agricultural management interact with the health of cocoa trees. We hypothesize that there are statistical correlations between farming practices, agrobiodiversity characteristics and cocoa tree health.
To test our hypothesis, we studied 38 AFS in the Agnéby-Tiassa region of Côte d'Ivoire, selected according to gradients of agrobiodiversity and intensity of farming practices. Half of the sample was conducted in organic farming, necessary to assess the effectiveness of natural pest regulations. The other half was conducted in conventional agriculture, which is the predominant management mode for Ivorian cocoa production. To characterize the agrobiodiversity associated with cocoa trees, we conducted botanical inventories, dendrometric monitoring, and mapping. This agrobiodiversity was then studied in two components: (i) plant composition, corresponding to the abundance of each associated crop species, and (ii) structure, including the variables of height stratum, basal area (m² ha-1), species richness, planting density (plant number ha-1) and spatial distribution (aggregated, random or regular). In addition, semi-structured interviews with farmers allowed us to characterize agricultural practices related to cocoa tree health, evaluate their perception of cocoa tree health, and map zones where cocoa trees are considered to be in "good health" (GH) and "poor health" (PH) according to their criteria. We created typologies of practices and associated agrobiodiversity (plant composition and structure) at the plot and zone levels through multivariate statistical analyses. We tested the relationships between these typologies with the management mode (organic vs conventional) at the plot level, and with cocoa health at the zone level, using Fisher's test.
Our results reveal that at plot level, although the inputs used are often different, organic farmers have a similar intensity of plot management to conventional farmers. There is a statistically significant correlation (p-value=0.05) between the associated agrobiodiversity structure and the management mode. Organic plots are distinguished by a higher specific richness of associated plants than conventional plots (26 compared to 17), also a larger basal area (10.2 m² ha-1 compared to 6.4 m² ha-1) and a higher average stratum (2.01 compared to 1.54).At the zone level, an almost statistically significant correlation is observed between agrobiodiversity structure and zone health, only for plots that are managed with organic farming (p-value=0.07). In these plots, GH zones are distinguished from PH zones by their specific richness with 11.0 vs 6.8.
Only structural characteristics of agrobiodiversity distinguish organic vs conventional plots: the trees associated in organic plots are taller and wider, and are represented by a greater diversity of species. By maintaining this structure, organic farmers certainly expect more services from agrobiodiversity than conventional farmers. In organic plots, the results at the health zone scale suggest that biological regulation depends on the specific richness of agrobiodiversity. The combination of results obtained at plot and health zone scales suggests that the structure of agrobiodiversity, including species richness, and not plant composition, has a positive impact on the biological regulations that can operate to maintain healthy cocoa trees. They open up new research perspectives to better understand the biotic and abiotic regulations that explain the better health of cocoa trees in GH zones compared to PH zones in organic agriculture. Regular quarterly assessment of the agroecological functioning of these health zones through measurements of the cocoa trees, the soil and the microclimate, associated with an assessment of agricultural practices using activity analysis methods, will help to better understand the links between practices, environment, and cocoa tree health, and thus contribute to identifying and designing more agroecological practices.

Speaker: Marie-Thérèse Morrisson (Centre de coopération internationale en recherche agronomique pour le développement (CIRAD))

61 Organic farming and seminatural habitats for multifunctional agriculture: a case study in hedgerow landscapes of Brittany

Introduction
Given the major impacts of chemical-based agriculture and landscape simplification on biodiversity, alongside climate change and human health, it is urgent to produce food in more sustainable ways (1). Crop fields and agricultural landscapes must promote biodiversity conservation and associated functions, including ecological regulation (e.g., predation, pollination), carbon sequestration, maintenance of water quality, and soil health protection (2). However, quantitative assessment of agroecosystem multifunctionality remains scarce (3), and few studies have simultaneously addressed belowground and aboveground organisms and functions (4). A better understanding of trade-offs and synergies between this wide range of taxa and functions would greatly inform the transition towards multifunctional agriculture.

Interactions between field- and landscape-scale factors are likely major drivers of multifunctionality in crop fields, but remain overlooked. For example, the effectiveness of local agri-environment schemes such as organic farming in promoting biodiversity and associated functions may depend on landscape context (5). In addition, landscape-scale studies are generally restricted to a context of chemical-based agriculture. Frequent agrochemical disturbances might undermine the beneficial effects of increased landscape heterogeneity (antagonistic effect) by preventing or limiting the spillover and population growth of beneficial organisms into conventional fields (6,7).

In this work, we investigated the effects of organic farming at field scale, total length of hedgerow networks in the landscape, and their interaction on the multifunctionality of winter cereal fields. We hypothesized that hedgerow landscapes promote the multifunctionality of crop fields, but also that their beneficial effects are stronger in organic systems, which are more prone to ecological intensification.

Methods
We conducted the study in the southern part of the Zone Atelier Armorique, a Long-Term Socio-Ecological Research site in Brittany, France. We selected 40 winter cereal fields under conventional vs organic farming, located along a gradient of total hedgerow length in the landscape. In 2019, we collected 21 indicators through sampling of crop fields and interviews with farmers. These indicators were used to estimate five agroecosystem goods: biodiversity conservation, nutrient cycling and soil structure, pest and disease regulation, food production, and socio-economic performance.

Results and discussion
Organic farming had higher level of functionality than conventional farming for many indicators, especially those related to biodiversity conservation and pest and disease regulation, despite a trade-off with food production. Total hedgerow length had much lower influence than organic farming on indicators, although we observed some positive interactions. Granivorous carabid abundance and semi-net margin were maximal in organic fields located in denser hedgerow landscapes. We conclude that reducing agrochemical input in crop fields is necessary to promote agroecosystem multifunctionality, whereas preservation of seminatural habitats alone is likely insufficient. Our study shows that organic farming and preservation of hedgerows are compatible or even preferable. More broadly, our results call for more ambitious research into the myriad possible combinations of farming practices and agri-environmental measures at both field and landscape scales, going beyond the context of chemical-based agriculture.

References
1. Altieri, M. A. & Nicholls, C. I. Agroecology and the emergence of a post COVID-19 agriculture. Agric Hum Values 37, 525–526; 10.1007/s10460-020-10043-7 (2020).
2. Kremen, C. & Merenlender, A. M. Landscapes that work for biodiversity and people. Science 362; 10.1126/science.aau6020 (2018).
3. Hölting, L., Beckmann, M., Volk, M. & Cord, A. F. Multifunctionality assessments – More than assessing multiple ecosystem functions and services? A quantitative literature review. Ecol Indic 103, 226–235; 10.1016/j.ecolind.2019.04.009 (2019).
4. Bardgett, R. D. & van der Putten, W. H. Belowground biodiversity and ecosystem functioning. Nature 515, 505–511; 10.1038/nature13855 (2014).
5. Concepción, E. D., Díaz, M. & Baquero, R. A. Effects of landscape complexity on the ecological effectiveness of agri-environment schemes. Landscape Ecol 23, 135–148; 10.1007/s10980-007-9150-2 (2008).
6. Stein-Bachinger, K., Preißel, S., Kühne, S. & Reckling, M. More diverse but less intensive farming enhances biodiversity. Trends Ecol Evol 37, 395–396; 10.1016/j.tree.2022.01.008 (2022).
7. Madin, M. B. & Nelson, K. S. Effects of landscape simplicity on crop yield: A reanalysis of a global database. PloS One 18, e0289799; 10.1371/journal.pone.0289799 (2023).

Speaker: Sébastien Boinot (Université Rennes)

113_BOINOT.pdf

Intercropping

Conveners: Treier Simon, Jingjing Zhang

62 Exploring the potential of wheat-soybean intercropping as a climate change adaptation in crop production

Exploring the potential of wheat-soybean intercropping as a climate change adaptation in crop production
1. Introduction
Due to climate change and agricultural intensification, crop production has been negatively influenced since the early 2000s. Yet, crop production needs to be doubled to feed the growing population by 2050. Crop diversification has the potential to enhance yield stability and increase sustainability under climate change (Birthal and Hazrana 2019; Bowles et al 2020). Intercropping, referring to two or more crops growing in the same field simultaneously is a vital option in crop diversification, which has been studied to outperform sole cropping in productivity, yield stability, and resilience to environmental stresses. Process-based crop models have been employed to simulate crop growth under future climate scenarios but focus only on main-stream cropping systems. To gain insights into intercropping of its essential mechanistic process and explore its potential adaptation strategy under climate change, we employ wheat-soybean relay-row intercropping as an example to: a) establish a low-parameter required crop model that can capture the light-competition of intercropping. (b) Investigate how climate change influences wheat and soybean yield in both sole and intercropped systems. 3) Explore to what extent a combination of intercropping and sowing date adjustments offset the negative impacts of climate change on crop productivity and save cultivated area.
2. Materials and methods
A two-year field experiment was conducted in Münche¬berg, Germany. Winter wheat and soybean in sole and Relay intercropping were cultivated in both rainfed and irrigation conditions. Field observations were used for model calibration and validation. The model is a revised version of the agro-ecosystem process-based model MONICA specified for relay-row intercropping, based on the ‘Horizontal Homogeneous Canopy’ model. Three general circulation models (GCMs) and two emission scenarios were employed to simulate the sole and intercropping wheat and soybean yield in Germany. Different sowing date combinations for wheat (six dates) and soybean (four dates) were tested under both moderate (RCP 2.6) and extreme (RCP 8.5) climate scenarios.
3. Results
By integrating the light-competition module into MONICA, and combining intercropping-specific calibration, the model showed acceptable prediction accuracy under both rainfed and irrigated conditions. The upscaling simulation to Germany showed that compared to the historical period (1981-2010), wheat soybean relay-row intercropping can achieve higher land-use efficiency (median Land Equivalent Ratio: 1.21, CV: 8%) than sole cropping under the futuristic high emission scenario (2031-2060). Even though, intercropping will decrease the total yield by 9% (median Transgressive Overyielding Index: 0.91, CV: 11%) under RCP 8.5. Optimizing sowing dates for component crops in intercropping can elevate productivity and land-use efficiency, with the highest value found when wheat is sown 30 days earlier and soybean plant 10 days later. The intercropping under the high-emission scenario has higher median LERs and lower CVs than that under the low-emission scenario, indicating its potential to stabilize crop yield under climate change.
4. Discussion
The intercropping version of MONICA focuses on the light competition, while below-ground competition regarding water and fertilization remains out of our scope. This simulation study was based on the experiment conducted in Germany, more field experiments involving various locations, component crops, or cultivars should be conducted for wider adoption possibilities. Under the current management level, transforming from sole cropping to intercropping increased the land-use efficiency but did not increase the total yield production. Optimizing sowing dates can aid the yield penalty but considering the feasibility of shifting sowing dates, fine-tuning and adapted machinery for intercropping are required. The indicators LER and TOI mainly emphasize yield production. Ecosystem services empowered by crop diversification were not evaluated in this study.
5. Reference
Birthal, P. S., & Hazrana, J. (2019). Crop diversification and resilience of agriculture to climatic shocks: Evidence from India. Agricultural Systems, 173, 345-354.
Bowles, T. M., Mooshammer, M., Socolar, Y., Calderón, F., Cavigelli, M. A., Culman, S. W., et al. (2020). Long-Term Evidence Shows that Crop-Rotation Diversification Increases Agricultural Resilience to Adverse Growing Conditions in North America. One Earth, 2(3), 284-293.

Speaker: Jing Yu (Leibniz centre for agricultural landscape research (ZALF))

87_Yu.pptx

63 Ability of the STICS soil-crop model for simulating performances and inter-specific interactions in tropical cereal-legume intercropping

Introduction
Intercropping offers the prospect of providing greater and more stable yield than sole-cropping in the face of climate change and increased climate variability. Cereal-legume intercropping is common in tropical cropping systems, but often with low legume density and limited or no nutrient inputs. Combining intercropping with integrated soil fertility management is a solution for promoting sustainable intensification. Long-term experiments investigating the impact of variations in soil and climate on intercrop performances are scarce throughout sub-Saharan Africa. Several models were designed to simulate intercropping, however their robustness and accuracy in reproducing intercropping functioning and performance have never been extensively evaluated for a range of tropical environments. This work aims to evaluate the robustness and accuracy of the STICS soil-crop model in simulating productivity and crop interactions for contrasting cereal-legume intercrops in tropical conditions.

Materials and methods
The STICS model (Beaudoin et al., 2023) was tested using data collected in on-farm and on-station experiments in Mali, Senegal, Burkina Faso, and Brazil. Various combinations of cereals (maize, sorghum, and millet) and legumes (pigeon pea and cowpea) were compared in sole cropping and intercropping. The experiments included contrasting spatial patterns, fertilizer inputs, crop varieties, sowing dates, and cereal/legume densities. The model was calibrated on sole cropping, and evaluated on intercropping. Observed and simulated partial Land Equivalent Ratio (pLER) was calculated to evaluate the ability of the model in simulating competition and complementarity effects in intercropping.

Results
We found that the STICS model had similar accuracy when simulating cereal grain yield of sole crops and intercrops. Model accuracy in simulating legumes was lower with intercropping compared with sole cropping. The model correctly reproduced competition and complementarity effects in intercropping between cereals and legumes in Mali and Burkina Faso and came close in Brazil (Figure 1). In Senegal, the model overestimated legumes’ pLER and underestimated cereals’ pLER, indicating that interspecific interactions where not correctly simulated for legumes with very low yields. Over all sites, the model simulated a reduction in legume yield due to light competition and a decrease in cereal yield due to competition for nitrogen. On the contrary, water stress had little effect on simulated yield, competition, and complementarity effects between crops.

Conclusion and prospects
This study provides evidence that the STICS model simulates intercropping with a good genericity and acceptable accuracy in contrasted tropical conditions, where legume yields are not too low. We are currently refining the calibration of the model and testing its latest version (beta version 11; Vezy et al., 2023) to better define the validity domain of STICS for tropical intercropping.

References
Beaudoin, N., Lecharpentier, P., Ripoche-Wachter, D., Strullu, L., Mary, B., Léonard, J., ... & Justes, E. (2023). STICS soil-crop model: conceptual framework, equations and uses.
Brisson, N., Bussiere, F., Ozier-Lafontaine, H., Tournebize, R., & Sinoquet, H. (2004). Adaptation of the crop model STICS to intercropping. Theoretical basis and parameterisation. Agronomie, 24(6-7), 409-421.
Justes, E., Bedoussac, L., Dordas, C., Frak, E., Louarn, G., Boudsocq, S., ... & Li, L. (2021). The 4C approach as a way to understand species interactions determining intercropping productivity. Frontiers of Agricultural Science and Engineering, 8(3), 3.
Baldé, A., Scopel, E., Affholder, F., Da Silva, F. A. M., Wery, J., & Corbeels, M. (2020). Maize relay intercropping with fodder crops for small-scale farmers in central Brazil. Experimental Agriculture, 56(4), 561-573.
Senghor, Y., Manga, A. G., Affholder, F., Letourmy, P., Bassene, C., Kanfany, G., ... & Falconnier, G. N. (2023). Intercropping millet with low-density cowpea improves millet productivity for low and medium N input in semi-arid central Senegal. Heliyon, 9(7).
Sow, S., Senghor, Y., Sadio, K., Vezy, R., Roupsard, O., Affholder, F., ... & Falconnier, G. N. (2024). Calibrating the STICS soil-crop model to explore the impact of agroforestry parklands on millet growth. Field Crops Research, 306, 109206.
Traoré, A., Falconnier, G. N., Ba, A., Sissoko, F., Sultan, B., & Affholder, F. (2022). Modeling sorghum-cowpea intercropping for a site in the savannah zone of Mali: Strengths and weaknesses of the Stics model. Field Crops Research, 285, 108581.
Vezy, R., Munz, S., Gaudio, N., Launay, M., Lecharpentier, P., Ripoche, D., & Justes, E. (2023). Modeling soil-plant functioning of intercrops using comprehensive and generic formalisms implemented in the STICS model. Agronomy for Sustainable Development, 43(5), 61.

Speaker: Mathilde DE FREITAS (AIDA, Univ Montpellier, CIRAD, Montpellier, France, 2CIRAD, UPR AIDA, F-34398 Montpellier, France)

64 Understanding and designing spring wheat/faba bean intercropping systems by virtually testing cultivar traits and management options

Cereal/legume intercropping allows for reducing inputs while achieving higher crop yields on the same land than expected from the monoculture crop yields of the constituent species. However, several studies have shown that the performance of intercrops depends on the genotypes chosen, crop management, and environmental conditions. Yet, evaluating multiple genotypes on various sites and under different climate and management conditions is not feasible to investigate all possible combinations (genotype × genotype × environment × management) of intercropping in field trials. Given the complexity of mixed cropping systems, crop models can be beneficial for testing hypotheses about the key factors driving competition and compensatory growth between species. Therefore, we conducted a virtual experiment to examine the interactions between a combination of varying plant heights, daily root elongation rate of species in intercropping, and nitrogen input to identify ideal traits and conditions that enhance the performance of spring wheat/faba bean intercropping at Campus Klein-Altendorf, Germany. Combining these three factors resulted in 1024 unique combinations. The simulation was conducted in the SIMPLACE (Scientific Impact Assessment and Modelling Platform for Advanced Crop Ecosystem Management) modeling framework (Enders et al., 2023). To consider climate variability, 100 years of synthetic climate data were generated by the stochastic weather generator LARS-WG (Semenov and Brooks, 1999) from historical weather data of 21 years (2001-2021). The simulations were run with a model solution in the modeling framework i.e. SIMPLACE (Intercrop model) which was previously calibrated and evaluated. During the scenario runs, the model was annually reinitialized two months before sowing to provide identical initial soil conditions. Moreover, a 100-year-long time series of weather data was clustered to high, medium, and low rainfall determined by the cumulative precipitation during the primary growth period (April to July), aiming to examine the interplay between precipitation levels and various management strategies.
The preliminary results suggest that there is considerable variability in the land equivalent ratio (LER) across different combinations of traits and fertilization rates. Considering each trait and management separately, while keeping other factors at the default value, the variation in plant height seems to have a minimal impact on LER, although there is a trend indicating that a combination of short spring wheat with tall faba bean genotypes leads to lower LER. This phenomenon is likely due to the faba bean intercepting a significant portion of light but being less efficient in its utilization. The partial LER of both species linearly varies with variation in plant height because the radiation interception of one species is inevitable at the expense of the other species, since both species are relatively short stature plants, spatial niche differentiation is negligible. Rooting depth appears as a critical factor governing LER, with combinations of shallow rooting spring wheat and deeper rooting faba bean cultivars exhibiting higher LER, demonstrating the spatial complementarity of water usage. Additionally, it is observed that higher nitrogen inputs result in lower LER compared to no input, underscoring the potential suitability of intercropping under conditions of low nitrogen input.
Considering the interaction of all three factors (nitrogen input, plant height, and rooting depth) and yearly variability, in a high rainfall growth period, optimum LER can be achieved under conditions of low nitrogen input when tall and shallow rooting depth spring wheat are intercropped with relatively short but deeper rooting faba bean cultivars. However, in low rainfall conditions, high LER can be achieved as long as the differences in rooting depth of the species are high enough for spatial complementarity of water use regardless of which species has a deeper rooting system. This suggests a complex interplay of factors influencing LER, highlighting the importance of careful selection and management of crop combinations in intercropping systems. Furthermore, expanding testing to encompass multiple traits, indices of intercropping performance, and management options under varying soil conditions is essential for developing comprehensive guidelines for optimizing intercropping systems.
Reference
Enders, A., Vianna, M., Gaiser, T., Krauss, G., Webber, H., Srivastava, A.K., Seidel, S.J., Tewes, A., Rezaei, E.E., Ewert, F., 2023. SIMPLACE — a versatile modeling and simulation framework for sustainable crops and agroecosystems, In Silico Plant 1–18. https://doi.org/10.1093/insilicoplants/diad006
Semenov MA & Brooks RJ (1999) Spatial interpolation of the LARS-WG stochastic weather generator in Great Britain. Climate Research 11:137-148 https://doi.org/10.3354/cr011137

Speaker: Dereje T. Demie (Institute of Crop Science and Resource Conservation, University of Bonn, Germany)

65 Developing Hi-sAFe-machine learning hybrid approach as a field-specific decision support system for agroforestry systems

Introduction
Germany aims to achieve carbon neutrality by 2045, with focus needed on the agriculture sector where agroforestry systems (AFS), such as alley-cropping, can serve as effective carbon sinks by cultivating perennial woody plants alongside annual crops or grasslands. According to (Beillouin et al., 2023), AFS are the most effective agricultural measure for increasing organic soil carbon content in proportion to area.Furthermore, the establishment, maintenance, and harvesting of the tree strips incurs additional expenditures and greenhouse gases (GHGs) emissions. AFS feature reduced wind speeds and altered evapotranspiration dynamics compared to normal arable farming systems (Markwitz et al., 2020). The Hi-sAFe model is a 3D model considering competition and facilitation, which are significant mechanisms explaining positive biodiversity-productivity relationships in biodiversity ecosystem functioning research, even though it does not explicitly incorporate biodiversity as a driver for outcomes like crop yield. Machine learning approaches are increasingly being used as data-driven tools to extract patterns and insights from the ever-increasing stream of geospatial data (Reichstein et al., 2019), but they have received less attention thus far in AFS.
Materials and Methods
Following extensive review, we found that the existing DSS lacks decision-making aids for cultivation recommendations and assessing AFS’s actual climate change mitigation potential, gaining different limitations (Figure 1). The Hi-sAFe agroforestry model (Dupraz et al., 2019) outperformed other models offering a unique 3D and spatially explicit framework to analyze tree-crop competition for light, water, and nitrogen. Incorporating factors such as climate, soil characteristics, species interactions, and management practices, Hi-sAFe provides a comprehensive platform for understanding the complexities of agroforestry systems. Microclimatic impacts, such as radiation (shading), temperature, humidity, and wind, depending on the distance to the wood strip and strip orientation, as well as the width, height, and density of the wood strip, are simulated in daily time steps for different woody features.
Results and Discussion
Multi-year (2009-2016) crop yield of oilseed rape and winter wheat in the narrow and wide crop alleys at different spaces from trees (0, 1, 4 and 7 m) were used in parameterizing Hi-sAFe. Since the model couples the pre-existing STICS crop model (Brisson et al., 2003) with a new tree model, we first calibrated STICS for diverse crops under conventional arable farming conditions. To ensure, deploying the model at spatial explicit in different environment, we integrated the Hi-sAFe model with machine learning algorithms such as Artificial Neural Network (ANN) and Convolutional Neural Network (CNN) as well as partial life cycle assessment for simulating yield and GHG in AFS at a robust and spatially explicit scale, allowing for a global assessment of GHG reduction potential.
Conclusion
The current approach combines Hi-sAFe with machine learning to fill the limitations of the past data driven tools, dataset, and models, creating a robust DSS for agroforestry systems. The EUS is designed to allow farmers and consultants across Germany to virtually create a wide range of agroforestry systems on their property, as well as find the best sites and methods for maximizing productivity and climate change mitigation.
Keywords
Agroforestry, alley cropping, poplars, crop rotation, life cycle assessment, winter wheat, oilseed rape
References
Beillouin, D., Corbeels, M., Demenois, J., Berre, D., Boyer, A., Fallot, A., Feder, F., and Cardinael, R. (2023). A global meta-analysis of soil organic carbon in the Anthropocene. Nature Communications 14, 3700.
Brisson, N., Gary, C., Justes, E., Roche, R., Mary, B., Ripoche, D., Zimmer, D., Sierra, J., Bertuzzi, P., Burger, P., Bussière, F., Cabidoche, Y. M., Cellier, P., Debaeke, P., Gaudillère, J. P., Hénault, C., Maraux, F., Seguin, B., and Sinoquet, H. (2003). An overview of the crop model stics. European Journal of Agronomy 18, 309-332.
Dupraz, C., Wolz, K. J., Lecomte, I., Talbot, G., Vincent, G., Mulia, R., Bussière, F., Ozier-Lafontaine, H., Andrianarisoa, S., Jackson, N., Lawson, G., Dones, N., Sinoquet, H., Lusiana, B., Harja, D., Domenicano, S., Reyes, F., Gosme, M., and Van Noordwijk, M. (2019). Hi-sAFe: A 3D Agroforestry Model for Integrating Dynamic Tree–Crop Interactions. Sustainability 11, 2293.
Markwitz, C., Knohl, A., and Siebicke, L. (2020). Evapotranspiration over agroforestry sites in Germany. Biogeosciences 17, 5183-5208.
Reichstein, M., Camps-Valls, G., Stevens, B., Jung, M., Denzler, J., Carvalhais, N., and Prabhat (2019). Deep learning and process understanding for data-driven Earth system science. Nature 566, 195-204.

Speakers: Dr Ahmed Kheir (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment), Prof. Til Feike (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment)

276_Kheir.pdf

66 Modelling the spatial distribution of light capture in strip intercrops

Introduction
Strip intercropping is a form of species mixture where the companion species are grown in narrow strips to allow species-specific management. Strong interspecific interactions occur between plants in the borders of these strips, whereas plants in the middle of the strips mostly compete for resources with conspecifics (Zhu et al., 2015). Light capture differs greatly between inner and outer rows of strips and is probably a driving force for yield effects in strip intercropping. However, light capture per row is hard to quantify. Here we use a ray tracing model to quantify how intercropping affects light capture in different rows of a strip.

Materials and methods
We conducted a modelling study, based on a field experiment performed in 2019 in the Netherlands (Wang et al., 2023). The experiment involved six bi-specific strip intercrops including maize (Zea mays L.), wheat (Triticum aestivum L.), faba bean (Vicia faba L.), and pea (Pisum sativum L.). Maize was sown five weeks later than the other three species. Each species was grown in 1.5 m-wide strips with three rows for maize, and six rows for the other three species. We reimplemented a ray tracing model (Gijzen and Goudriaan, 1989; Wang et al., 2017), using measured plant height and leaf area index as model inputs, to estimate light capture per row in intercrops and monocrops.

Results
In the modelled relay intercrops, the early-sown species all captured more light in the intercrop border rows than in the inner rows and monocrops due to the initial absence of neighbouring maize (Fig. 1). Inner rows of the early-sown species did not show such light capture advantages. Compared to monocrop maize, border row maize in intercrops only captured more light when growing with wheat and pea, but not with faba bean because faba bean was taller than wheat and pea, and caused substantial early shading on maize, which was only partially compensated after faba bean harvest. Inner row maize captured more light in all intercrops. The simultaneous intercrops without maize did not show complementarity for light capture, and any (light capture) advantage for one species was offset by a disadvantage for the other species. Faba bean substantially reduced light capture of wheat and pea in all intercrop rows, whereas the faba bean itself only obtained a substantial increase in light capture in the border rows, and only a slight increase in the inner rows.

Discussion
This study indicates that relay intercrops, which exhibit temporal complementarity, are more efficient in capturing light compared to simultaneous intercrops, where species coexist for most of the season. These results align with the light capture advantages found in maize/wheat relay strip intercropping in the Netherlands (Gou et al., 2017; Zhu et al., 2015), suggesting that the positive effects of temporal complementarity in light capture apply to both cereal/cereal and cereal/legume combinations. The early-sown species benefited from border rows capturing more light in the early season. The late-sown maize increased light capture in both border and inner rows after the early companions had been harvested, with significant decreases in border rows with tall-statured companion species, highlighting the importance of early season competition. Use of the ray tracing model allows analysing species or variety combinations, strip widths and sowing dates are suitable for light-capture-efficient intercropping.

References
Gijzen, H., Goudriaan, J., 1989. A flexible and explanatory model of light distribution and photosynthesis in row crops. Agric For Meteorol 48, 1–20.
Gou, F., van Ittersum, M.K., Simon, E., Leffelaar, P.A., van der Putten, P.E.L., Zhang, L., van der Werf, W., 2017. Intercropping wheat and maize increases total radiation interception and wheat RUE but lowers maize RUE. European Journal of Agronomy 84, 125–139.
Wang, Z., Dong, B., Stomph, T.J., Evers, J.B., L. van der Putten, P.E., Ma, H., Missale, R., van der Werf, W., 2023. Temporal complementarity drives species combinability in strip intercropping in the Netherlands. Field Crops Res 291, 108757.
Wang, Z., Zhao, X., Wu, P., Gao, Y., Yang, Q., Shen, Y., 2017. Border row effects on light interception in wheat/maize strip intercropping systems. Field Crops Res 214, 1–13.
Zhu, J., van der Werf, W., Anten, N.P.R., Vos, J., Evers, J.B., 2015. The contribution of phenotypic plasticity to complementary light capture in plant mixtures. New Phytologist 207, 1213–1222.

Speaker: Dr Zishen Wang (Centre for Crop Systems Analysis, Wageningen University & Research)

On-farm changes to support agro-ecological transitions: profitability and motivation

Conveners: Toni Klemm, Timothy Green

67 Balancing profitability, protein production, and pesticide reduction: what are the levers for action for French arable farms?

The agricultural sector has experienced significant changes over time. The current issue lies not only in enhancing its economic and productive performance but also in safeguarding the environment. Thus, the interest of this work that investigates ways to balance farmers’ profitability with environmental preservation and food supply goals. Our contribution to the academic literature is threefold. Firstly, we provide a detailed examination of three agricultural strategies — maximizing profitability, enhancing protein production, and minimizing pesticide usage — assessing their impact on farmers' income, operational expenses, and environmental sustainability. Secondly, we conduct an opportunity cost analysis using the profitability maximization scenario as a reference point, highlighting the financial trade-offs inherent in pursuing varied agricultural objectives. Thirdly, we employ an innovative methodology that considers prices as an optimization variable within activity models, offering a more comprehensive and realistic evaluation of agricultural economics. We apply data envelopment analysis to panel data from the Meuse department in France for the period 1991-2017. We show that optimal profitability is achieved by increasing farmers' income while simultaneously reducing operational costs, including pesticide use. In contrast, while the protein maximization strategy leads to an increase in pesticide costs, the pesticide minimization strategy slightly diminishes protein yield. The opportunity cost analysis emphasizes significant trade-offs: pursuing protein maximization incurs additional costs compared to the profitability-centric approach, as reflected in the balance between yield increase and cost changes. Similarly, adopting the pesticide minimization strategy amplifies the opportunity costs even more when contrasted with prioritizing profitability. Our findings suggest that achieving a balance among the three scenarios requires improved crop management and practices, with price adjustments playing a secondary role. The opportunity cost analysis emphasizes the need for a paradigm shift towards farming systems that balance economic returns, environmental stewardship, and food nutritional quality, particularly by integrating protein-rich crops into longer crop rotations. This transition is crucial for the sustainability of agriculture and the well-being of future generations, marking a significant step towards a more resilient and food-secure world.

Speaker: Ms Salomé KAHINDO (IESEG School of Management)

68 What motivate West African cocoa farmers to value trees? Taking the 4Ws approach to the heart of the field

1.Introduction

West Africa, the primary cocoa-producing region globally, has experienced significant deforestation over the past decades, largely attributed to the expansion of cocoa cultivation by small-scale farmers. Farming cocoa represents generally the main source of income for farmers (Sonwa et al., 2019). In efforts to restore forest cover, states have implemented large-scale policies aimed at promoting agroforestry (Dieng & Karsenty, 2023). Most studies aimed at understanding farmers' strategies for adopting agroforestry have remained highly disciplinary, often lacking a comprehensive consideration of all social (Who?), historical (When?), geographical (Where?), and ecological (What?) determinants underpinning farmers' motivations in tree valorization.

2.Materials and Methods

Drawing from a sample of 150 farmers responsible for managing 12,096 trees, by surveys we (i) quantified farmers’ motivations for 10 material and immaterial uses of trees and (ii) explored by stone-ranking method (Sheil et al., 2004), the relative importance of the 4Ws in explaining overall motivations, specific to each use, as well as the varying levels of specialization in farmers tree management strategies. Analysis of data was carried out in Bayesian framework using an adapted form of the Monte Carlo Hamiltonian sampler (Carpenter et al., 2017):

$X_p\sim P\left(\lambda_p\right)\ with\ \lambda_p=e^{\left(\sum_{i=1}^{i=n}(\theta_{cov}*Cov_i)\right)}$

Where $X_p$ representing motivation types, $\lambda_p$ the parameter of the Poisson model, the effect of covariates  $i$ was then tested by incorporating them into an exponential function.

3.Results

Findings indicate that the value attributed to trees by cocoa farmers is strongly influenced by various variables underlying the 4Ws: the identity and history of the farmer in charge of managing the plot are indeed important, the specific characteristics of the plantation, the territorial context in which it is situated, and the historical trajectory of the plot are equally significant, yet the effects of each 4W determinant depend on the material and immaterial uses considered.

4.Discussion

To encourage cocoa farmers to optimally diversify the valorization of their trees (Codjo et al., 2017), two significant levers are identified: (i) enhancing farmers’ abilities to recognize trees and (ii) reducing cocoa tree density by eliminating less productive individuals from the field. From a political perspective, it is urgent for stakeholders involved in promoting agroforestry to consider all dimensions of the farmer-field system (Sanial et al., 2023). The diversity of farmers’ life trajectories (Who), cultivated landscape variations (Where), eld diversities (What), and historical trajectory distinctions (When) present both constraints and opportunities with which farmers must contend to transition towards the much-desired agroforestry systems.

5.References

Carpenter, B., Gelman, A., Hoffman, M. D., Lee, D., Goodrich, B., Betancourt, M., Brubaker, M. A., Guo, J., Li, P., & Riddell, A. (2017). Stan: A probabilistic programming language. Journal of Statistical Software, 76(1). https://doi.org/10.18637/jss.v076.i01

Codjo, A. E., Armel, A. T., & Emmanuel, O. (2017). Importance and Role of Biodiversity and Tropical Forests in the Cultural, Socio-Economic and Religious Life of African Black People: Case of Benin. Journal of Environmental Science and Engineering B, 6(6), 312–322. https://doi.org/10.17265/2162-5263/2017.06.003

Dieng, N. S., & Karsenty, A. (2023). Power through trees. State territorialization by means of privatization and ‘agrobizforestry’ in Côte d’Ivoire. World Development Sustainability, 3(June 2022), 100074. https://doi.org/10.1016/j.wds.2023.100074

Sanial, E., Ruf, F., Louppe, D., Mietton, M., & Hérault, B. (2023). Local farmers shape ecosystem service provisioning in West African cocoa agroforests. Agroforestry Systems, 97(3), 401–414. https://doi.org/10.1007/s10457-021-00723-6

Sheil, D., Puri, R. K., Basuki, I., van Heist, M., Wan, M., N., L., Rukmiyati, M.A., S., I., S., K.D., S., Chrisandini, E., P., E.M., A., F., G., B., J., & A., W. (2004). A la découverte de la biodiversité, de l’environnement et des perspectives des populations locales dans les paysages forestiers. In A la découverte de la biodiversite, de l’environnement et des perspectives des populations locales dans les paysages forestiers: methodes pour une etude pluridisciplinaire du paysage.

Sonwa, D. J., Weise, S. F., Schroth, G., Janssens, M. J. J., & Shapiro, H. Y. (2019). Structure of cocoa farming systems in West and Central Africa: a review. Agroforestry Systems, 93(5), 2009–2025. https://doi.org/10.1007/s10457-018-0306-7

Speaker: Marie Ruth Dago (Institut National Polytechnique Félix Houphouet Boigny, Yamoussoukro, Côte d'Ivoire)

69 French Tea Time: An economic analysis of the emergence of tea production in France

In a context of agro-ecological transition, territorialization of food systems and adaptation to climate change, new agricultural products are increasingly appearing in areas where they were not historically present. These new productions may particularly rely on consumer preferences for geographical proximity and strong territorial identity (Atallah et al. 2021). They represent an opportunity to diversify existing farms or may be associated with the development of new economic models and market channel strategies, as shown by Hill et al (2023) on hemp production in the US.

In France, tea production, although still at an early stage of development, is expanding with the arrival of new producers, particularly in the Brittany and Occitanie regions. This trend raises a number of interesting scientific questions: how to structure a new industry based on a food product that has no history in the region? What are the associated economic models and relationships between stakeholders in the sector? What are the opportunities and motivations for developing new local production of an already highly globalized commodity? As in the case of other crops that are re-emerging in certain French regions such as saffron (Girard and Navarrete, 2005) or hops (Rousselière et al. 2023), we hypothesize that the challenges facing tea production in France relate in particular to production and installation costs, strategies for market positioning and efforts to structure the sector in a sustainable and collectively beneficial way.

In order to characterize the development of this new sector and to identify the motivations and obstacles encountered, we conducted a series of exploratory semi-directive interviews with 13 tea producers at different stages of their project. Our results show a certain diversity in the profile of producers. Unlike traditional agricultural installations, the majority of respondents did not come from farming backgrounds and were not as closely linked to the usual organizations such as local Chambers of Agriculture, land operators, farming unions or inter-professional organizations. The process of setting up a tea farm therefore tends to follow an individual logic. However, we have identified a dynamic network of producers structured around two sub-groups of individuals, each led by producers who were pioneers in tea-growing experimentation in France. Finally, by asking respondents about the level of trust they have in their professional partners, our results show that a higher level of trust is associated with more frequent (more than once a month) and more local interactions.

We discuss the possible ways in which the sector could evolve and underline the importance of a more integrated and collaborative approach in order to meet the collective needs inherent in the early stages of any emerging new food chain, such as the need to develop a technical reference system or to adopt specifications clarifying the territorial dimension. In terms of policy implications, we discuss that such strategies of novel crop choices may be a lever for inciting young farmers setting up and may directly contribute to agricultural development by strengthening local food systems with more diverse productions but at the same time, in order to be sustainable, cooperation and communication between producers and within the supply chain is key to ensure quality and commonly accepted rules.

References

Atallah, S. S., Bazzani, C., Ha, K. A., & Nayga Jr, R. M. (2021). Does the origin of inputs and processing matter? Evidence from consumers’ valuation for craft beer. Food Quality and Preference, 89, 104146

Girard, N., & Navarrete, M. (2005). Exploring Synergies between Scientific and Empirical Knowledge: The Case of Saffron and Truffle Cultivation in France. Natures Sciences Societes, 13(1), 33-44.

Hill, R., Jablonski, B. B., Van, L., Wang, M., Patalee, B., Shepherd, J., ... & Thilmany, D. (2023). Producers marketing a novel crop: a field-level view of hemp market channels. Renewable Agriculture and Food Systems, 38, e22.

Rousselière D., Coisnon T., Gillard E., Musson A., & Rousselière S (2023) A divorcement between Local and Organic? Exploring the hop supply contract strategies of French craft breweries, Paper presented at Journées de recherches en sciences sociales, Paris, décember.

Speakers: Prof. Damien Rousselière (Institut Agro Rennes Angers), Thomas COISNON (member)

70 The importance of understanding and examining the moral dimensions of farmers’ economic life for their culture of cooperation

Cooperation in rural areas has become an important research objective in recent years. As part of efforts to revitalize rural areas, researchers have often examined the economic and environmental dimensions of cooperation. Agricultural economists have emphasized the importance of farmers’ market cooperation in reducing costs and increasing the competitiveness of family farms in the food supply chain. Other research has discussed the importance of farmer cooperation at regional and environmental levels for the conservation of biodiversity and ecosystem services. Many researchers have investigated why farmers do not collaborate despite the benefits and have identified the lack of trust and diversity of value systems as the main barriers to successful and long-term collaboration in rural areas (Ostrom, 2007; Riley et al., 2018; Westerink et al., 2017).
The ethnographic research was also based on the question of why farmers do not cooperate, but focused on the under-researched moral dimensions of farmers’ cooperation. It examined the moral sentiments, motives and actions of farmers, who consequently have different experiences with and views on formal and informal forms of cooperation in their rural communities. The study was conducted in north-eastern Slovenia, where other researchers have identified the need for greater economic and environmental cooperation between farmers (Erjavec et al., 2016). The research methodology was based on focused ethnography (periodic short-term fieldwork) and 7 months of participant observation. The researcher conducted more than 50 semi-structured interviews between 2018 and 2023, mainly with members of farming families, but also with agricultural extension workers, priests, journalists, representatives of agricultural companies and organisations, and others. The collected empirical material was analysed using the moral economy approach, which focuses on people’s conceptions of a life worth living, their attributions of responsibility for a decent life, and their perceptions of injustice in economic relationships (see Narotzky and Besnier, 2014; Sayer, 2011; Thompson, 1993).
The ethnographic study has shown that farmers often associate their well-being with their ability to invest systematically in the development of the farm. According to the farmers, their economic situation has become increasingly unstable over the last 15 years. This has had a negative impact on their culture of cooperation, as they have traditionally activated family networks and imposed new responsibilities on close relatives in uncertain times. In addition, farms have been abandoned and farmers find it difficult to work with so-called reliable and comparable production partners as there are not many farmers nearby. This is also the case because in practise there are many moral judgments and sentiments of envy, resentment and injustice towards other farmers. According to the respondents, the moral sentiments arise due to land abuse, unequal informal sharing of machinery, collapse of cooperatives, cheating by traders and lack of entitlement to subsidies. Moreover, farmers do not cooperate because they believe that they cannot change and overcome the power imbalance in the food supply chain.
All this shows that the farmers interviewed will find it difficult to unite for various reasons. They emphasise that they need a just and hardworking person to restore and maintain their culture of cooperation. In the socialist past, this function was often performed by local researchers and agricultural advisors, who are no longer as present in rural communities as they were in the past.

Erjavec E., Juvančič L., Rac I., Dešnik S. 2016. Agriculture-based strategies for areas hit by economic crisis (Slovenia): Case study SI-3. Grad, Pegasus
Narotzky S., Besnier N. 2014. Crisis, value, and hope: Rethinking the economy. Current Anthropology, 55, S9: S4–S16
Ostrom E. 2007. Collective action theory. In: The Oxford handbook of comparative politics. 1st ed. Boix C., Stokes S. (eds.). Oxford, Oxford University Press: 186–208
Riley M., Sangster H., Smith H., Chiverrell R., Boyle J. 2018. Will farmers work together for conservation?: The potential limits of farmers’ cooperation in agri-environment measures. Land Use Policy
Sayer A. 2011. Why things matter to people: Social science, values and ethical life. 1st ed. Cambridge, Cambridge University Press
Thompson E. P. 1993. Customs in common. 2nd ed. London, Penguin Books
Westerink J., Jongeneel R., Polman N., Prager K., Franks J., Dupraz P., Mettepenningen E. 2017. Collaborative governance arrangements to deliver spatially coordinated agri-environmental management. Land Use Policy, 69: 176–192

Speaker: Mateja Slovenc Grasselli (Research Centre of the Slovenian Academy of Sciences and Arts (ZRC SAZU))

362_Slovenc Grasselli.pptx

71 Forestry transition interaction and farm trajectories on pioneer fronts: insights from Amazon Basin in Guaviare and Paragominas

In the Amazon agricultural is a major driver of deforestation and losses of biodiversity.. Understanding farm trajectories may provide insights into new pathways for the development of sustainable territories.
This research conducted in the pioneer fronts of Guaviare and Paragominas aims to explore the contributions of different farm trajectories to the establishment of sustainable territories. We emphasize the significant role of family work group dynamics, of women and agroecological principles in shaping farm trajectories and fostering territory sustainability.
Patches within the study sites were selected based on spatial factors such as land use, roads, settlements, and forest transition status (conservation, regeneration, degradation, and deforestation), as well as trades off between agricultural development and environmental conservation identified through interviews with key informants. Drawing from existing literature on farm trajectories in the Amazon Forest and key informant interviews, we constructed six archetypes representing the possible farm trajectories in the study sites and that correspond to most common trajectory patterns (e.g. substance slash and burn, pasture intensification in beef cattle, cattle in land expansion). Through a snowball sampling technique, we conducted 55 semi-directed interviews with both male and female farmers.
We found three additional archetypes highlighting ongoing shifts in trajectory patterns, influenced by factors such as local markets and land propriety rights. Our findings also revealed that farm trajectories limiting forest degradation or deforestation are found in farms presenting financial constraints or with aged farmers. In patches with favorable territorial conditions, such as accessible roads and supportive public policies, the first phases of trajectories are always associated to deforestation. However, in later stages of farm trajectories farmers tend to use agroecological principles while some of them kept on deforesting
Bifurcations within work groups such as separations, illnesses or deaths of the heads of the family are were a driver of the observed trajectories, however, change of the number of family members did not affected trajectories. Women play a fundamental role in stable trajectories, by performing most of the agricultural tasks performed by men, by participating to the management of the farm and through their off-farm activities. Our findings indicate that women who are alone tend to be in an unstable phase of their farm trajectory.
This study provides valuable insights into the complex interactions between farm trajectories, forest transition, and sustainability in pioneer fronts.
Past and present farm trajectory patterns should be discussed in order to analyze the extent to which sustainable farm pathways can be built in the future.

Speaker: Andrés Vega-Martinez (CIRAD)

10:55 AM Coffee break

Diversification in crop production

Conveners: Aurélie Metay, Mareike Beiküfner

72 Opening barriers for lentil agri-food system production in France

Context description and research question: Ensuring healthy diets from sustainable food systems is an immediate challenge (Willett et al., 2019). On the one hand, there is an urgent need to limit the environmental impact of production systems while increasing their resilience in the face of climate change. On the other hand, consumer health is also an important point to consider when analyzing food systems (Tilman & Clark, 2014). The aim of this study was to assess locks and levers associated with lentil production at the country scale, in a European temperate climate country like France. The three dimensions assessed in more detail were agro-ecology, food safety and economics, three essential pillars for assessing sustainability and go to synergistic solutions. They were discussed in a broader context of protein and agro-ecological transitions.
Method and theoretical background: Data were obtained through 1-to-1 interviews and questionnaires, on-line surveys, literature search and access of national and international database. On the agricultural dimension, we identified and interviewed thirty-three farmers in different areas in France, reflecting different production systems. On the food safety dimension, we analyzed 607 responses to the on-line survey to assess microbiologic and chemical risks. On the economic dimension, we analyzed 45,885 purchases of lentils products in France, from 13,039 households. Statistical analyses on each dataset were carried out to compute agronomic, food safety and economic indicators. Data were analyzed through different tools (Excel, Stata and R software).
Results and discussion: On the agricultural dimension, first, 88% of farmers emphasized that redesigning crop rotation is a strong lever for sustainable lentil growing systems. Second, we found that farm economic profitability is an essential condition for farmers to produce lentils. Organic or geographical indication areas were identified to secure land allocation for lentil production and farmers' income. Third, lentil production was pointed out to be vulnerable to climate change, with climatic hazards having an impact on yields and thus on economic profitability. On the food safety dimension, the microbiological and chemical risks associated with lentil consumption were assessed as low considering the current consumption of the French population. However, we recommend to be careful in the future if the consumption increases drastically. On the economic dimension, we found that the per capita consumption of lentil-based food products is low, although given the relatively low level of prices, these may not be a limit to consumption. Moreover, we pointed out that the French market strongly depends on imports, and especially on Canada for lentil in can.
Our study revealed that there were still several obstacles to the development of the lentil agricultural and food system in France and that those identified obstacles cannot be neglected if we want to implement a viable protein and agroecological transition in the medium or long term in France and more generally in European countries with temperate climates. Obstacles associated with the agroecology-safety-economy triptych must be compared to the sector's positive effects in terms of health benefits and environmental impact. We recommend therefore to take our conclusions into a more general cost-benefit type approach encompassing these five dimensions in order to holistically evaluate the lentil sector and to place its strengths and weaknesses in relation to other important agri-food system in France such as cereals and meat food systems. Greater research on this perspective could facilitate protein and agro-ecological transitions in France and more generally in Europe as a long-term goal. Besides, nationwide policy measures to support lentil production on the one hand and to encourage consumption on the other hand, should be designed consistently.

Speaker: Marie Thiollet-Scholtus (INRAE)

63_Thiollet-Scholtus.pptx

73 Adoption of cereal-legume intercropping in France: a matter of outlets?

Intercropping consists of growing two or more crop species simultaneously on the same field [1]. Cereal-legume intercrops are a particularly beneficial association, with benefits in controlling the spread of diseases, insects and weeds [2], which can reduce chemical inputs use [3] while improving protein content and yields [4]. Despite all those benefits, cereal-legume intercrops are not widely grown in France as farmers face technical and economic barriers [5,6]. To better support farmers in adopting cereal-legume intercropping, it is necessary to identify the factors favourable to its adoption on farms.

Here, we propose a quantitative study highlighting the factors structuring the adoption of cereal-legume intercropping on French farms. Our objectives are (i) to identify the main factors fostering the adoption of cereal-legume intercropping at the national scale and (ii) to determine the existence of factors at the local level that differ from those observed at the national level.

We used data from the 2020 French Agricultural Census, a national survey conducted once every ten years that provides an exhaustive photograph of the French agricultural situation (Metropolitan France and French overseas departments and regions). The survey follows two questionnaires, one more detailed than the other and only used on a sample of 70,000 farms (from a total of 450,000 farms) representative of French agriculture. We used data from the more detailed questionnaire, focusing on the 43,968 farms specialised in arable crop, mixed crop-livestock or livestock systems, which have the potential to grow mixtures of cereals and legumes. Based on a literature review, we identified 42 variables that can affect the adoption of cereal-legume intercrops. These variables cover aspects related to types of farming, organic and conservation agriculture, agroecological practices, marketing channels and involvement in groups of farmers. Then, we performed a Random Forest analysis to select the most relevant variables among those 42 at the national level. For more interpretability, we represented the results with a Classification and Regression Tree (CART). To account for local specificities, we ran the CART model obtained at the national level on three areas where we identified strong dynamics of adoption based on French agricultural statistics (Centre-East, around Jura department, dominated by dairy cattle farming; South, around Aveyron department, dominated by sheep and meat cattle farming, and Centre-West, around Loire-Atlantique department, a more diversified area, with arable, cattle, and mixed crop-livestock farming).

Our results indicate that in France, organic farming, grain storage on farms, and livestock with feed autonomy for cattle and sheep are the main factors linked with the adoption of cereal-legume intercropping. Grain storage on farms and animal feed autonomy indicate that farmers use their intercrops on farms or sell them outside the agricultural cooperative channels. These findings suggest that the availability of outlets can represent a critical factor in adopting cereal-legume intercropping. Only a few agricultural cooperatives in France collect intercrops, and only in organic farming systems. The belonging to a farm machinery cooperative also came out as a factor favouring the adoption, as it can help overcome technical barriers through shared equipment and knowledge. We found the same factors at the local level but with some specificities. Our results suggest that local dynamics can be created through collective actions in the short term and the development of new market opportunities in the longer term.

[1] Willey, R. W. Intercropping: its importance and research need. I. Competition and yield advantages. Field Crop Abstr. 32, 1–10 (1979).
[2] Corre-Hellou, G. et al. The competitive ability of pea–barley intercrops against weeds and the interactions with crop productivity and soil N availability. Field Crops Res. 122, 264–272 (2011).
[3] Yan, E., Munier-Jolain, N., Martin, P. & Carozzi, M. Intercropping on French farms: Reducing pesticide and N fertiliser use while maintaining gross margins. Eur. J. Agron. 152, 127036 (2024).
[4] Raseduzzaman, Md. & Jensen, E. S. Does intercropping enhance yield stability in arable crop production? A meta-analysis. Eur. J. Agron. 91, 25–33 (2017).
[5] Mamine, F. & Farès, M. Barriers and Levers to Developing Wheat–Pea Intercropping in Europe: A Review. Sustainability 12, 6962 (2020).
[6] Verret, V., Pelzer, E., Bedoussac, L. & Jeuffroy, M.-H. Tracking on-farm innovative practices to support crop mixture design: The case of annual mixtures including a legume crop. Eur. J. Agron. 115, 126018 (2020).

Speaker: Elodie Yan (Université Paris-Saclay, INRAE, AgroParisTech, UMR SADAPT, F-91120 Palaiseau, France)

21_Yan.pdf

74 Introducing grain legumes in Mediterranean cropping systems as a strategy to increase their productivity and sustainability

1. Introduction:
   European agriculture is specialized in cereal production, presenting agronomic and environmental risks, and increasing the dependence on imported high-value protein (Watson et al., 2017). For instance, rainfed and irrigated Mediterranean agriculture is highly based on continuous winter cereals and maize (Zea mays L.), respectively. The objectives were to i) redesign and assess Mediterranean rainfed and irrigated cropping systems when introducing grain legumes, ii) maximise soybean (Glycine max Merr.) performance by exploring later maturity groups than currently used, and iii) study alternative soybean weed management strategies for irrigated single and double cropping systems (SCS and DCS, respectively).
2. Materials and methods:
   Redesigned cropping systems were assessed in two on-farm field experiments from 2019 to 2022 and managed under no-till management practices. In the rainfed area, the focus was on diversification with pea (Pisum sativum L.), faba bean (Vicia faba L.) and a multiservice cover crop as alternatives to wheat (Triticum aestivum L.) combined with increasing N fertilization rates (0, 40, 80, 120 kg N ha-1). Under irrigated conditions, crop diversification (soybean introduction) and intensification (from SCS to DCS) were studied as alternatives to continuous maize. In both cases, cropping systems’ productivity (energy and protein) and N use efficiency were calculated (Simon-Miquel et al., 2024a, 2023a). At the soybean crop level, the field experiments focused on soybean maturity groups (from 00 to III) for SCS and DCS (Simon-Miquel et al., 2024b) and sustainable soybean weed management strategies including row width narrowing (75 to 37.5 cm), herbicide application and using a roller-crimped rye (Secale cereale (L.)M.Bieb.) cover crop for SCS and the two former ones for DCS(Simon-Miquel et al., 2023b).
3. Results:
   Legumes introduction in rainfed and irrigated cropping systems led to an increase in protein production and a decrease in energy production per unit of surface. Under rainfed conditions, N fertilization increased protein yields, with the faba bean cropping system presenting the highest yields at all N fertilizer rates. Under irrigated conditions, diversification with soybean in the SCS did not lead to an increase in protein production (921 kg ha-1 yr-1, on average). Instead, intensification with barley (Hordeum vulgare L.)-maize, and especially barley-soybean DCS, showed a higher protein production (1129 and 1778 kg ha-1 yr-1, respectively). A range of 17-28% yield increase was observed in cereals following legumes in rainfed and irrigated cropping systems. In the rainfed systems, 18% and 40% of the total N input in the pea and faba bean cropping systems was supplied by biological N fixation, respectively. A positive net N balance (i.e. biologically fixed N > exported N) was found in most cases, likely contributing to the pre-crop effects. The use of later soybean maturity groups (II and III) than currently used (00 to I) led to yield increases ranging from 33% to 80% in SCS. Regarding soybean weed management, a reduction of 92% of weed biomass was observed when rye biomass was 11.4 t DM ha-1, whereas no effect was found below 4 t DM ha-1. Narrowing row widths did not affect weed pressure or soybean yield, probably due to the presence of mulches (rye in SCS and barley crop residues in DCS).

4. Discussion:
   Cropping systems redesign with a larger share of grain legumes is a strategy to increase protein production while reducing the need for synthetic N fertilizer in Mediterranean areas, thus contributing to their sustainability. Such an increase in protein production is accompanied by a decrease in energy production (Notz et al., 2023), although partially offset by the positive pre-crop effects of legume crops on the following cereal. Soybean yield under Mediterranean irrigated conditions can be improved with the use of later maturity groups, confirming previously simulated results across Europe (Nendel et al., 2023). The use of a roller-crimped rye cover crop in a soybean SCS can be an effective weed control strategy, provided enough rye biomass is accumulated before soybean planting.

5. References
   Nendel et al. 2023. https://doi.org/10.1111/gcb.16562
   Notz et al. 2023. https://doi.org/10.1007/s13593-022-00861-w
   Simon-Miquel, G. et al. 2023a. https://doi.org/10.1016/j.eja.2023.126817
   Simon-Miquel, G. et al. 2024a. https://doi.org/10.1016/j.fcr.2024.109307
   Simon-Miquel, G. et al. 2024b. https://doi.org/10.1016/j.fcr.2024.109274
   Simon-Miquel, G. et al. 2023b. https://doi.org/10.1002/agj2.21409
   Watson, C.A.et al. 2017. https://doi.org/10.1016/bs.agron.2017.03.003

Speaker: Dr Genís Simon-Miquel (Department of Agricultural and Forest Sciences and Engineering - Agrotecnio-CERCA Center, Universitat de Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain)

75 Legume-based crop rotation impacts productivity and resource use efficiency in south-eastern Australia

Legume-based mixed cropping systems play a crucial role in maintaining crop productivity while reducing reliance on inorganic nitrogen inputs and enhancing resilience under climate change.
Our research provides valuable insights into the long-term economic and ecological implications of adopting specific legume-based crop rotation systems, thus empowering growers to make informed decisions and facilitating widespread adoption.
The study used APSIM simulations to evaluate four distinct crop rotation systems: Canola-wheat (R1), Lucerne-lucerne-lucerne-canola-wheat (R2), Fababean-canola-wheat-barley-fababean-wheat (R3), and Fababean-barley-oat-canola-lupin-wheat (R4), considering varying nitrogen levels (0, 50, 100, 150, and 200 kgN/ha) across different climate scenarios covering historical (1984-2024) and future projections under RCP2.6, RCP4.5, and RCP8.5 (2025-2085) in four contrasting locations (Boorowa, Cootamundra, Condobolin, and Ardlethan) in NSW.
The study revealed notable differences in soil organic carbon increase (R2>R4>R3>R1) regardless of nitrogen fertilizer rates, with diminishing differences among crop rotations as nitrogen level increased. Considering wheat as a benchmark, the highest yields were observed in R1 and R3 (R1>R3) compared to R2 and R4 but yield variability increased. Moreover, the study highlights a relatively greater yield response to nitrogen rates in R1 and R3 (R1>R3). Therefore, integrating legumes such as lucerne, fababean and lupin significantly enhanced soil organic carbon levels while maintaining crop yields, suggesting the potential to achieve optimal yields with reduced fertiliser nitrogen input.
This research highlighted the value of legume-based crop rotations to improved productivity, resource-use-efficiency, and resilience of agricultural systems and offers practical insights for sustainable agricultural practices in southeastern Australia.

Speaker: Fekremariam Mihretie (CSIRO)

ESA_PPT_Fekre.pptx

76 Improvement of chickpea yield through intercropping with common wheat in two Mediterranean locations

The growing interest in locally produced plant-based proteins calls for an increased European production of minor grain legumes, including chickpea (Cicer arietinum L.). However, the European agricultural area dedicated to pulses is less than 3% of the total arable land. The scarce cultivation of grain legumes is due to multiple factors, among them the low yields coupled with yield instability between years, which derives from the high susceptibility of grain legumes to abiotic and biotic stresses. Nonetheless, the practice of intercropping has been demonstrated to stabilise legume yields. However, there is still few information on the effect of the cultivar on intercropping performance.

The main objective of this study is to evaluate whether it is possible to stabilise the yield of chickpea through its intercropping with wheat (Triticum aestivum L.) in a Mediterranean environment. Furthermore, we investigate which chickpea cultivar is most suitable for intercropping. The experiment was organised in a randomised complete block design with four replicates. Three experimental factors were investigated: chickpea cultivar, intercropping and location.
The trial considered five chickpea cultivars, of which three belong to the Kabuli group (Sultano, Lambada and Castellano) and two to the Desi group (Nero della Murgia and Castor). They are commercial cultivars from Italy (Sultano and Nero della Murgia), France (Lambada and Castor) and Spain (Castellano). The wheat cultivar used was Bolero. Each chickpea cultivar was grown as a sole crop and in intercropping with wheat. The study started in spring 2023 and will end in spring 2025, in two locations: Pisa, Central Italy and in Udine, Northern Italy. Both locations fall under the North Mediterranean climate category, as indicated in the Environmental Stratification of Europe, despite having different rainfall pattern. No pesticides or fertilisers were used, and mechanical hoeing weeding was performed once on the sole crops of chickpea to simulate the standard agronomic management for low input chickpea sole crop.

Results

The 2023 results show similar behaviour in terms of grain yield and aboveground biomass of both the chickpea cultivars and wheat, with higher values in Pisa than in Udine.

In both locations, on average, chickpea aboveground biomass was lower in intercropping than monocropping, regardless the chickpea cultivars. The biomass reduction due to intercropping was 38% in Pisa and 74% in Udine. Significant differences between cultivars were found only in Pisa and only in intercropping, where the cultivars that produced more biomass than the others were Sultano and Lambada. In Pisa, at chickpea flowering, intercropping significantly reduced the aboveground biomass of weeds. This underlines the ability of the cereal to suppress weeds in the early stages of legume development. No differences in weed development were observed between the different cultivars.

On average, chickpea produced 33% less when intercropped than when in sole crop. The most performing cultivar was Lambada, whereas Sultano was the least productive. Wheat grain yield was on average higher in Pisa than in Udine. In both locations wheat grain yield was significantly lower in intercropping, except for the co-cultivation with Castellano in Pisa. This is probably due to the lower germination in the field and lower biomass production per m^2 of Castellano compared to the other cultivars, which allowed the wheat to produce more (Fig. 1).

This study lays the foundation for evaluating whether intercropping of chickpea and wheat can stabilise chickpea yields. Furthermore, the study shows that the cultivar choice is highly relevant for the success of intercropping in a Mediterranean environment. Lambada was identified as the most suitable one. The study will be repeated in the following years to establish if indeed intercropping is able to stabilise chickpea yield.

Speaker: Gabriele Nerucci

271_Nerucci .pdf

77 Combination of crop production strategies for plant protein production in Europe

Plant proteins are part of the new generation of proteins for the green transition towards a neutral European continent in 2050. The cultivation of protein crops reduces the climate footprint, diversifies production systems and enhances human nutrition. Hence, the SMART PROTEIN EU project has targeted four species to develop sustainable protein supply chains for the future: fava beans, lentils, chickpeas and quinoa. To increase the cultivation area with these species, cropping systems need to be optimized. For this purpose, partners located both in North and South of Europe, tested combined production strategies involving the management of the genotype, environment and production practices for pest and disease control towards productivity enhancement. As weed control strategies, Denmark combined in three species (fava beans, lentils and quinoa) the following strategies: sowing dates (early and late, separated by 7 days) with the preparation of a false seed bed (10 days preceding sowing), and a subsequent harrowing 30 days after sowing. The Netherlands validated a decision support tool, founded in plant pathology data bases, in order to define the best rotation that included fava bean. In addition, they compared the production under conventional vs organic (management) with different genotypes of this pulse. In the south of Europe, Spain tested on-farm the combination of species (intercropping with chickpea) with mechanical crop management (harrowing) and in lentils the synergy of the number (1 to 3) and time of harrowing passes (early and late passes separated by 6-15 days). Finally, Italy tested different levels of irrigation (1/3 and 2/3 of full ETo) both in chickpeas and lentils.
Main results outlined that the combination of strategies leaded to the control of weeds. In The north of Europe (Denmark), the implementation of the false seed bed strategy in early sowings of the three protein crops reduced weeds by up to 10% compared with the late sowings as it was revealed by drone images. When this strategy is used and combined with mechanical control, weed prevalence can be reduced. In the southern region of Europe i.e. Spain, weed control tested through intercropping (chickpeas and spring wheat) and harrowing gave the following results: compared with the sole chickpea crop, intercropping reduced weed density by 34% whereas harrowing reduced weeds by 42%. The combination of both techniques: intercropping + harrowing reduced weeds in a total of 70% resulting in a very efficient strategy for weed control. In lentils,
early harrowing was more effective for weed reduction than late harrow passes (55% vs 30% with one pass and 64% vs 35% with two passes). The validation of a decision support tool such as Best4Soil helped in the Netherlands to suggest convenient crop rotations with fava beans that reduce risks of yield damage caused by pathogens linked to the introduction of protein crops. The comparison between conventional versus organic production of different fava beans genotypes in the Netherlands depicted cultivars tolerant to diseases (LG Viper, LG Cartouche) that can reach interesting yields of up to 5 t ha-1 without the use of chemicals. Finally, in Italy, different levels of irrigation did not have significant differences in chickpea but in lentils, with an irrigation that considers 1/3 of the ETo it is possible to enhance yields by 24% (1.679±0.36 kg ha-1). These experiences in the north and south of Europe highlight the importance of multi-strategy approaches that consider different components, tools and stakeholders. The combination of production strategies can enhance protein production under organic systems. Nevertheless, non-favorable climate events and the lack of adapted genetic materials to the pedo-climatic conditions are important limitations to consider.

References.
Alba, O. S., et al. (2020). "Increased seeding rate and multiple methods of mechanical weed control reduce weed biomass in a poorly competitive organic crop." Field Crops Research 245: 107648.
Jensen, E. S., et al. (2015). "Enhanced yields in organic arable crop production by eco-functional intensification using intercropping." Sustainable Agriculture Research 4(3).
Pelzer, E., et al. (2017). "Design, assessment and feasibility of legume-based cropping systems in three European regions." Crop and Pasture Science 68(11): 902-914.
Sellami, M. H., et al. (2021). "Evaluation of Genotype, Environment, and Management Interactions on Fava Beans under Mediterranean Field Conditions." Agronomy 11(6): 1088.

Speaker: Dr Gabriela Alandia (University of Udine, University of Copenhagen)

Increasing biodiversity for improving resiliency of farming systems

Conveners: Vincent Faloya, Maitane Juárez Mugarza

78 Performance and stability of wheat variety mixtures: a multivariate analysis

Introduction
In the face of climate change, improving the stability of food production systems is critical. Increasing diversity in agricultural fields can be a way to stabilize production across time and/or space. Variety mixtures represent a practical way to introduce diversity at the genotype level (Kopp, 2023). In Switzerland, variety mixtures remain rarely used, due to uncertainties and lack of understanding of the processes driving potential benefits for productivity, quality, and stability. This research presents results from a multi-year, multi-site wheat variety mixture experiment investigating the role of variety mixtures to increase crop performance and stability, and the mechanisms underlying these effects.

Methods
The experimental design included 8 Swiss wheat varieties in a diallel design (i.e. all varieties in pure stand and all 2-variety mixtures) and one mixture combining the 8 varieties. The experiment was replicated three times with a full randomized block design. We set up the field trials in three Swiss sites varying in environmental conditions, during three years (from 2021 to 2023). We measured a variety of agronomic parameters, such as yield, protein content, thousand kernel weight, hectolitre weight, Zeleny, but also functional traits during the growing season, for instance height, heading date, specific leaf area, etc. Crop performance and stability was assessed using Weighted Average of Absolute Scores as well as Multi-trait Stability Index as described by Olivoto et al. (2019). We examined links between mixture performance, stability, and characteristics of the varieties composing the mixtures with linear regressions, as described in Stefan et al. (2023). We hypothesized that mixtures composed of more different varieties – in terms of genetic distance but also morphological, agronomic, or synchronicity aspects – would be more performant and/or stable.

Results
Mixtures generally had a positive effect on yield, but not on protein content. Unlike what is commonly assumed, results of the multitrait stability index do not show that variety mixtures universally increase stability (Fig. 1). The 6 most stable plots include 3 varieties in pure stands, and 3 mixtures (2 of them including the most stable variety). Regarding traits or mechanisms explaining crop performance and stability, preliminary results indicate that (1) asynchrony of the components is positively linked to temporal and spatial yield stability, as already shown by Stefan et al. (2023), (2) the mean performance and stability of mixture yield is negatively correlated with the monoculture difference in specific leaf area (mixtures are more yield-performant when combining varieties with similar specific leaf area) and (3) multitrait stability is better when combining varieties with a high difference in phenology.

Discussion
This study investigates the links between performance and stability of wheat variety mixtures and various traits of the mixture components. It uses a multicriteria approach to evaluate crop performance and stability, by including agronomic parameters (such a yield, thousand kernel weight) but also quality parameters (protein content, zeleny sedimentation rate). Therefore, it allows to not only look at productivity, but also at the quality of the grains produced, and the stability of this quality. The complexity of the multivariate responses and explanatory variables requires more in-depth investigation; however, we can already state that our study confirms the defining role of asynchrony in driving yield stability, showing that combining less synchronous varieties (in terms of yield) can act as an insurance to environmental variability. This supports the role of variety mixtures as a promising solution to sustainably increase the stability of wheat production in Europe.

References:
Kopp, E. B., Niklaus, P. A., &Wuest, S. E. (2023). Ecological principles to guide the development of crop variety mixtures. Journal of Plant Ecology, 16(6).
Olivoto, T., A.D.C. L\'ucio, J.A.G. da silva, B.G. Sari, and M.I. Diel. 2019. Mean performance and stability in multi-environment trials II: Selection based on multiple traits. Agron. J. 111:2961-2969.
Stefan, L., Fossati, D., Camp, K.-H., Pellet, D., Foiada, F., & Levy, L. (2023). Asynchrony is more important than genetic distance in driving yield stability in wheat variety mixtures. Crop Science, 1–15.

Speaker: Dr Laura Stefan (Agroscope)

ESA_2024.pdf

79 Contrasted reaction norms of wheat yield in pure vs mixed stands explained by tillering plasticities and shade avoidance

1. Introduction
   Cultivar mixtures are increasingly used as a practice to diversify crops, notably for cereals such as wheat. Cereal mixtures typically yield higher than the individual components grown in monoculture, although with notable variability (Borg et al., 2018). This variability stems from plant-plant interactions within mixed stands, resulting in diverse plant phenotypes, a phenomenon known as phenotypic plasticity. This study aims to (i) assess the extent of phenotypic plasticity in yield between monoculture and mixed stands, (ii) determine the key yield components contributing to this plasticity, and (iii) establish connections between such plasticities and variations in functional traits such as plant height and flowering time.

2. Materials, methods
   A novel experimental approach relying on precision sowing enabled the phenotyping of each cultivar within mixtures at the individual plant level, focusing on above-ground traits throughout the growth cycle. Eight commercial cultivars of Triticum aestivum L. were cultivated both in pure stands and mixed stands in field plots over two consecutive years (2019-2020, 2020-2021), encompassing contrasted climatic conditions. The management strategy included nitrogen fertilization, fungicide application, and weed removal. Two quaternary mixtures were sown, each comprising cultivars with contrasted height or earliness. The spatial layout of cultivars within each mixture was achieved by randomization (Lieng, Richardt and Dodgson, 2012), ensuring that the varietal identity of each plant was known throughout the experiment.

3. Results
   Compared to the average of cultivars in pure stands, the height mixture strongly underyielded over both years (-29%) while the earliness mixture overyielded the second year (+11%) and underyielded the first year (-8%). The second year, the magnitude of cultivar’s grain weight plasticity, measured as the difference between pure and mixed stands, was significantly and positively associated with their relative yield differences in pure stands (R2=0.51). We found that some cultivars were dominant, i.e. more productive, in mixtures and that dominance rankings were maintained over both years (Figure 1). When grain weight plasticity, measured as the log ratio of pure over mixed stand, was partitioned as the sum of plasticities in each yield component, its strongest contributor was the plasticity in spike number per plant (~56% of the sum), driven by even stronger but opposed plasticities in both tiller emission and regression. For both years, the plasticity in tiller emission was significantly, positively associated with the height differentials between cultivars in mixture (R2=0.43 in 2019-2020 and 0.17 in 2020-2021).

![enter image description here][1]

Figure 1 - Reaction norms of mean grain weight per plant between pure and mixed stands per cultivar for both mixtures in both years. Vertical segments represent confidence intervals at 95%. Letters indicate pairwise differences between cultivars in pure or mixed stands. Line types indicate if plasticity is significant.

1. Discussion
   The new experimental design enabled to access to the behavior of each individual plant, and hence to assess plant plasticity in pure vs mixed stands. Despite variable cultivar performances in mixture over the two years, some cultivars remained dominant and, unlike common guidelines, dominance was not related to earliness or height at maturity. Our results also highlighted a link between plasticity in tiller emission and height differential in mixture. Both height and tillering dynamics displayed plasticities typical of the shade avoidance syndrome. The early recognition of potential future competitors for resources via a light quality signal is a known example of active plasticity and, as demonstrated here, a major component of genotype strategies in mixtures. The decomposition of plasticities developed in this study open avenues to better study plant-plant interactions in agronomically-realistic conditions. This study also contributed a unique, plant-level data set allowing the calibration of process-based plant models to explore the space of all possible mixtures (Blanc et al., 2021).

2. References

Blanc, E. et al. (2021) ‘Functional–Structural Plant Modeling Highlights How Diversity in Leaf Dimensions and Tillering Capability Could Promote the Efficiency of Wheat Cultivar Mixtures’, Frontiers in Plant Science, 12, p. 734056.

Borg, J. et al. (2018) ‘Unfolding the potential of wheat cultivar mixtures: A meta-analysis perspective and identification of knowledge gaps’, Field Crops Research, 221, pp. 298–313.

Lieng, H., Richardt, C. and Dodgson, N.A. (2012) ‘Random Discrete Colour Sampling’. The Eurographics Association.

Speaker: Dr Meije Gawinowski (Université Paris-Saclay, INRAE, CNRS, AgroParisTech, GQE - Le Moulon, 91190 Gif-sur-Yvette, France)

223_Gawinowski.pdf

80 Differences in growth features between species are driving cereal-legume intercrop yield

Crop diversification is increasingly promoted as a mean to improve the sustainability of agriculture while maintaining a sufficient level of food production [1]. Intercropping is a farming practice that combines at least two crop species in the same field for most of their growing periods [2], and where the two components are harvested and eventually sorted. Since plants vary in their ecophysiological functioning, a mixture of different crop species could improve the resource use efficiency, relative to its component species grown separately in sole crop. Mixtures between cereal and legume species are a prime example, on one hand because of their complementarity in nitrogen use [3], on the other hand because of its technical operationality [4].

Reports from meta-analysis [5] overall indicate that intercropping is a candidate practice for sustainability, based on its increased productivity per unit area. However, reports based on the outcomes of field experiments [6] indicate that these benefits are largely context-dependent [7]. We argue that shifting from a broad logic linking diversity to productivity to an understanding of how species features impact crop productivity is key to developing intercropping practices. More precisely, we propose to assess how the difference between associated species features are linked to the mixture productivity.

For that, we gathered a set of 37 field experiments in Europe [8] containing species-dependent measurements along with mixture and sole crop productivity. We first characterized each species by summarizing time series for plant growth (leaf area, height, biomass) into key features such as maximum value, rate or delay in growth. We then quantified plant-plant interactions with indicators based on differences between these features (relative trait distances in community ecology). We also characterized the cropping environment using climate and soil variables, including an indicator related to the plant nitrogen status (nitrogen nutrition index NNI, [9]).

We modeled the mixture performance as a function of environment and plant-plant interactions using a mixed-effect random forest (MERF, [10]), which is a method combining a machine learning and a mixed effect model. We used two steps to interpret our model and identify which features were important for the mixture performance. We first reduced the set of features to focus on using a stringent variable selection process during model fitting [11] and then ranked the selected variables by estimating their contribution to the variance of the mixture performance (variable importance).

We showed that features related to inter-specific plant interactions (differences between species within the mixture) were more selected and important than the ones related to species response to mixture (differences between managements). The selected features thus mainly indicated that competitive processes shape the outcome of a mixture. Among them, the difference in biomass accumulation rate, representing the strength of the competition, was consistently more important than other features. Overall, the yield of a species in mixture was positively correlated to its dominance, here captured by its stature (height, leaf area, biomass), at the expense of the associated species. Features related to the climate and to cultivars were not selected.

While we miss features related to below-ground interactions, our study contributes to understanding how management options, such as species choice or nitrogen management, have an impact on the mixture performance through their effect on the competitive strength of one given associated species.

References
[1] Beillouin D et al., 2019, https://doi.org/10.1088/1748-9326/ab4449.
[2] Willey RW, 1980, https://doi.org/10.1017/s0014479700010802.
[3] Landschoot S et al., 2024, https://doi.org/10.3389/fpls.2023.1228850.
[4] Verret V et al., 2020, https://doi.org/10.1016/j.eja.2020.126018.
[5] Martin-Guay M-O et al., 2018, https://doi.org/10.1016/j.scitotenv.2017.10.024.
[6] Jones SK et al., 2023, https://doi.org/10.1016/j.baae.2022.12.005.
[7] Duru M et. al, 2015, https://doi.org/10.1007/s13593-015-0306-1.
[8] Mahmoud R et al. 2024, https://doi.org/10.24072/pcjournal.389.
[9] Louarn G et al., 2021, https://doi.org/10.1016/j.eja.2021.126229.
[10] Hajjem A et al., 2012, https://doi.org/10.1080/00949655.2012.741599.
[11] Kursa MB et al., 2010, https://doi.org/10.18637/jss.v036.i11.

Speaker: Dr Pierre Casadebaig (INRAE)

slides_esa_casadebaig.pdf

81 Identifying keys of success for relay intercropping of service crop in a winter cereal

Introducing service crops into rotations may help to reduce dependency to inputs. Service provision largely depends on biomass production (Vrignon-Brenas et al., 2016b). Relay intercropping into winter cereal may favor conditions for service crop emergence, without impairing cereal yield (Gardarin et al., 2022). Nonetheless, this technique is complex and service crop establishment could fail, preventing its large adoption by farmers. Soil and climate conditions can explain variability of success (Vrignon-Brenas et al., 2016a). It is also the result of competition for resources in a complex system formed by winter cereal, service crop and weeds. This study takes profit from 15 years of experiment on such technique to determine what are the key factors to succeed in establishing the service crop for the provision of expected services.

The database used gathers data from 46 on-farm trials settled in south eastern part of France between years 2008 and 2023. Most of them were organic (39), or in transition to organic (6) or conventional (1). In these experiments red or white clovers were sown as service crops (SC) into a winter cereal (WCC) at the end of winter. A total of 1097 quadrat of 0.25m² sampled at cereal crop harvest were compiled. Cereal, service crop and weeds (W) dry biomass were measured at cereal harvest. A Hierarchical Clustering on Principal Components permitted to determine typical groups of situations. Other data were collected such as crop and weeds density at cereal flowering, characterization of soil, climate and agricultural (crop sequence and management) conditions. A multivariate regression tree (MRT) was built as a first exploration on how these data explained SC biomass variability.

4 groups (G1 to G4) of situations are statistically defined. Mean dry biomass measured at cereal harvest for all groups are 9 T DM/ha, 0.5 T DM/ha and 0.3 T DM/ha for cereal, weeds and clover respectively. G1 represents situations where WCC biomass is high (12.8 T DM/ha) and largely dominant, preventing W and SC to grow (respectively 0.3 and 0.1 T DM/ha in average). In the other groups, WCC biomass is much lower (mean dry biomass of the group of 7.1, 7.7 and 6.2 T DM/ha in G2, G3 and G4 respectively). G2 gathers situations where growth conditions appear to be constraining and total (WCC+SC+Weeds) biomass production is low. G3 situations presented high SC biomass (1.9T DM/ha) and reduced W biomass (0.2T DM/ha). G4 situations are the exact reverse with high biomass of W (3.6T DM/ha) and almost no SC (0.1T DM/ha). The latter gathers few situations (n=54), mainly corresponding to one field trial. MRT suggests that, except in some rare instances where climate conditions are especially favourable, SC biomass is largely penalized first by WCC higher biomass. Clover density at wheat flowering lower than 250pl/m² is also penalizing SC biomass production (n=667). Rainfall accumulation and/or fine soil texture appear to be favourable for this SC density, provided that W infestation is controlled.

Vrignon-Brenas et al (2016a) mentioned a minimum SC biomass of 0.5T DM/ha to ensure weed regulation after WCC harvest. Such SC biomass is rarely observed here while situations with almost no SC biomass at cereal harvest are much more frequent. Competition with WCC appeared to be the first cause of SC failure. The threshold of penalizing WCC biomass determined here corresponds to highly productive organic conditions but reduced conventional ones. It suggests that this technique is poorly adapted in such conditions, at least without changing WCC sowing (e.g. interrow width). Situations of group 4 highlights how important it is that weed infestation is moderate to permit clover establishment. Finally, the analysis we process here suggest that some soil and climate conditions are more favourable for SC establishment and survival. Further analyses are needed to better define these conditions.

Gardarin, A., Celette, F., et al. 2022. Intercropping with service crops provides multiple services in temperate arable systems: a review. Agron. Sustain. Dev. 42, 39. https://doi.org/10.1007/s13593-022-00771-x
Vrignon-Brenas, S., Celette, F., et al. 2016a. Biotic and abiotic factors impacting establishment and growth of relay intercropped forage legumes. Eur. J. Agron. 81, 169–177. https://doi.org/10.1016/j.eja.2016.09.018
Vrignon-Brenas, S., Celette, F., et al. 2016b. Early assessment of ecological services provided by forage legumes in relay intercropping. Eur. J. Agron. 75, 89–98. https://doi.org/10.1016/j.eja.2016.01.011

Speakers: Dr Olivier Duchêne (ISARA), Florian Celette (ISARA)

82 Intercropping in Europe: a systematic mapping study of arable grain crops

Introduction
In recent years intercropping (IC) has increased in prominence in research globally and produced a large legacy of empirical evidence. A bibliometric study on cereal-legume IC found 4735 articles and revealed that on a continental scale most publications originated from Asia (China 785, India 626), followed by the Americas (1003) and Europe (943) (Landschoot et al., 2024). This wealth of evidence was synthesized in meta-analytic studies, indicating the advantages but also limitations of IC systems. Recently, a global study showed that IC outperformed sole crops (SC) with respect to land use efficiency when the aim was to produce a diversity of products while IC systems are not better but close to SC if the overall highest yield is the goal (Li et al., 2023). In contrast to this strong evidence for their high potential, in Europe IC are still confined to small niches of fodder and biomass production or catch crops while there is a wide implementation gap for food crops (Timaeus et al., 2022). A current challenge is to structure the wealth of empirical research to inform strategic IC research to develop cropping systems that fit the diverse ecological, technological and economic contexts of European agriculture. As one step towards these goals, we conducted a review of IC studies following the systematic map approach of James et al. (2016). A systematic mapping approach is able to answer a broad research question and to identify research gaps and facilitate knowledge synthesis. We addressed the following research question: What is the state of experimental research on IC systems with two arable grain crops in Europe?
Materials and methods
We developed a search combining a cereal grain crop and an intercrop search string, that consisted of synonyms for each concept. These strings were combined with an exclusion string for terms that are irrelevant to our research question. To restrict the geographic scope to Europe a country filter was added. The search string was developed iteratively in the web of science (WoS) database and tested against a benchmark list of 30 articles known to be relevant for our research question. The final search string missed only one of these 30 articles and this was considered to be sufficiently comprehensive for our research question. The final search was conducted on November 24, 2023 in the WoS core collection without any time restrictions. References were exported to Zotero to remove duplicates. Screening of titles and abstracts against the eligibility criteria was done in the Rayyan software. Studies needed to include two arable grain crops and be conducted in Europe. Studies that were reviews, meta-analyses, pure modeling or social science were excluded. Full text screening was done manually by reading the pdf files and documentation in an excel database.
Preliminary results outlook
The search in WoS yielded 2080 articles. Screening these articles against eligibility criteria resulted in 661 eligible articles from which 621 could be retrieved as full texts. Full text screening resulted in 449 eligible articles. The top five countries with the most studies were Germany (75), France (49), Turkey (46), Poland (44), and UK (32). While data extraction was not yet conducted, the screening already revealed some gaps. Biodiversity conservation effects of IC were only addressed in six, strip intercropping in eight and testing of agricultural technology for IC management in zero articles. The next step is to extract metadata from the experiments describing what has been studied in detail. An analysis of knowledge gaps and knowledge clusters will be presented at the conference.
References
James, K.L., Randall, N.P., Haddaway, N.R., 2016. A methodology for systematic mapping in environmental sciences. Environ. Evid. 5, 7. https://doi.org/10.1186/s13750-016-0059-6
Landschoot, S., Zustovi, R., Dewitte, K., Randall, N.P., Maenhout, S., Haesaert, G., 2024. Cereal-legume intercropping: a smart review using topic modelling. Front. Plant Sci. 14. https://doi.org/10.3389/fpls.2023.1228850
Li, C., Stomph, T., Makowski, D., Li, H., Zhang, C., Zhang, F., van der Werf, W., 2023. The productive performance of intercropping. Proc. Natl. Acad. Sci. U. S. A. 120. https://doi.org/10.1073/pnas.2201886120
Timaeus, J., Ruigrok, T., Siegmeier, T., Finckh, M.R., 2022. Adoption of Food Species Mixtures from Farmers’ Perspectives in Germany: Managing Complexity and Harnessing Advantages. Agriculture 12, 697. https://doi.org/10.3390/agriculture12050697

Speaker: Madhuri Paul (University of Bonn)

83 Phenotypic traits of sunflower varieties vary according to the composition of cover crops

Cover crops (CCs) are known to improve soil fertility and cash crop performances. Introducing CCs mixtures is a promising approach to increase multifunctionality of the ecosystem services provided by CCs. However, the effect of CC mixtures on subsequent crop yield remain contrasted. Indeed, the extent to which yields are increased by CCs depends on the type and management of CCs, the type of cash crop, the application of fertiliser to the cash crop, the soil and climatic conditions. In the context of climate change, drought is a major environmental factor that limits crop growth, photosynthesis and yield. Sunflower, which is adapted to environments with low N and water requirements, has different drought-tolerance strategies, depending on the variety. However, little is known about the variability in the response of drought-tolerant sunflower varieties to CCs in low-input systems.

The study’s aims were to characterise CC ecosystem services mainly related to C, N and water and how ecosystems services of CC influence responses of sunflower varieties that differed in drought sensitivity. CC and sunflower varieties were organized in a randomized non-complete block design with a split-plot arrangement in 2021-2022 and 2022-2023. CC treatments consisted of a pure grass CC (rye), a mixture of legume CC (purple vetch/fodder pea), 3 mixtures of legume and non-legume CC (faba bean/white mustard/phacelia; fodder pea/rye/ purple vetch and faba bean/indian mustard/phacelia) and a relay CC treatment (forage sorghum then faba bean). The control of CC treatments is a bare soil kept free of weeds mechanically by two passes of a cultivator during intercrop. Sunflower varieties had different drought tolerance strategies for leaf expansion (LE) and transpiration (TR): a conservative strategy for LE and TR (MAS 86OL), a conservative strategy for LE and productive strategy for TR (MAS 89M), a productive strategy for LE and a conservative strategy for TR (MAS 98K) and a productive strategy for LE and TR (CARRERA CLP). Implantation, development, growth, N statue and productivity were evaluated on sunflower varieties preceded by CCs by low- and high-throughput phenotyping measurements. Various variables of growth and development were based on image processing tools using UAV RGB images.

The results indicate that CCs affected late N release absorption by sunflower, increasing the seed filling period. Indeed, maturity stage was delayed by an average of 194 °C.d for Faba bean/Mustard/Phacelia in 2021-2022 and 344 °C.d after Pea/Rye/Vetch in 2022-2023, compared to Faba bean/Forage sorghum and bare soil, which can lengthen grain filling period by average of 342 °C.d in 2022-2023 (equivalent to 17 days in average).
Optimized choice of CC allows equivalent yields to intensively tilled bare soil, while increasing carbon restitution and weed control in low-input agricultural systems. Mixtures with C:N ratio lower than 19 were composed of more than 60 % of legume species biomass led to early and high N uptake from the vegetative stage while other CCs with higher C:N ratio composed of legume and non-legumes led to late and high N uptake after flowering. The composition of CCs led to higher yields compared to other CC treatments but similar yields to intensively tilled bare soil. However, in a multifunctional approach to the ecosystem services provided by CCs, carbon restitution and weed control were higher after CCs than after intensively tilled bare soil. Moreover, these results are similar to those of the study of Ait-Kaci et al. (2022) which showed no clear trend of sunflower yield increase after CC mixture with legume in a four-year field experiment.
Sunflower growth can be improved by optimizing the choice of CC and sunflower varieties. During the drought year, higher biomass was observed for productive sunflower for leaf expansion in presence of early and late N release by CCs. Our results can guide sunflower variety selection and CC type and management in low-input systems to better match N release from CC residues with subsequent cash crop response during vegetative and post-flowering phases. Further research is needed to understand the responses of varietal traits to the agroecological system.

Ait Kaci Ahmed, N., Galaup, B., Desplanques, J., Dechamp-Guillaume, G., Seassau, C., 2022. Ecosystem Services Provided by Cover Crops and Biofumigation in Sunflower Cultivation. Agronomy 12, 120. https://doi.org/10.3390/agronomy12010120

Speaker: lucie souques (INRAE)

On-farm changes to support agro-ecological transitions: co design

Conveners: Antonin Pépin, Wiebke Reymann

84 Integrating crop and livestock beyond farm level: how serious games may help co-designing collaborations between neighbouring farmers

Crop-livestock integration is a theoretical ideal for sustainable agriculture. Albeit decreasing due to limiting factors at the farm level (e.g. work constraints), crop-livestock integration beyond farm level is seen as a promising option. However, local integration between neighbouring farms requires collective redesign to address organizational issues faced with increasing levels of spatial and temporal coordination (Asai et al., 2020). Specific methodologies are needed to co-design scenarios of crop and livestock coordination beyond farm level, involving a diversity of local actors.

We aimed to show how serious games can be used to cope with this challenge. We focused on supporting co-design of scenarios in two French regions considering neighbouring farm collaboration to reintegrate crop and livestock.

Two serious games, Dynamix and Oviplaine, were built using the same principles: i) a participatory approach taking multi-actor needs and objectives into account (e.g. livestock farmer, shepherd, crop farmer) (Barreteau et al. 2014) , ii) facilitate exchanges between farmers to build collective strategies, iii) consider technical changes at farm level and organizational changes at farmer group level, iv) include a spatially-explicit board game (map of the region).

Dynamix allows co-designing flows of grain, fodder and manure between neighbouring farms taking storage and transportation into account. Albeit Dynamix includes animal tokens, grazing on neighbouring farm is not its core. Oviplaine is an adaptation of Dynamix focused on cover crop grazing on crop farms. It allows to design day-by-day grazing itineraries for herds from plot to plot. Both games include simulation models allowing to consider supply-demand balanced for each type of crops and grassland, and seasonal variations in production. In Dynamix, a multicriteria evaluation of the co-designed scenarios allows to discuss benefits and trade-offs at the individual farm and group levels.

We applied the games with two groups of farmers: i) Dynamix in south-western France, with 4 crop aiming to diversify their cropping systems and to sell grain and fodder to livestock farmers and 5 livestock farmers interested in local and non-GMO feed for their animals; ii) Oviplaine in a specialized crop area, in the Parisian Basin with 4 crop and 1 livestock farmer aiming to build an itinerary for the herd.
Dynamix helped to quantify technical scenarios for each farm and equilibrate a local supply-need balances with 81.4 tons of cereals, 25.6 tons of protein crops, 120 tons of hay and 154 tons of manure. As crop farmers did not want to spend time dealing with storage and transportation of exchanged materials, two complementary organisational options were considered: i) plan one-on-one collaborations with individual livestock farmers able to store grain and fodder and ii) involve a local cooperative to facilitate logistics and agreements, anticipate needs and find more farmers if necessary.

Oviplaine helped the participants to build an itinerary from September to February. Some plots could be grazed during a few days, others for a few weeks. Seasonal availability of resources was estimated according to climate and crop farmers practices. The map helped to discuss the possible routes, access to water, possibilities to fence the plots, escape risks and eventual fallback zone in case of raining and damages on fields.

Both approaches confirmed the importance of working with spatially-explicit board games, tokens and maps to facilitate discussions and planning between participants. They allowed taking into account the spatial, temporal and organizational aspects. Both approaches are complementary. While Dynamix considers a larger diversity of actors, including famers and possibly third-party to organize logistical aspects over a year, Oviplaine focuses on the technical aspects of day-by-day cover crop grazing to follow the herd’s itinerary. Applying the serious games on two case-studies with different contexts, actors and challenges revealed their strong potential. Games can easily be scaled-out to other agricultural contexts.

References
Asai M., Moraine M., Ryschawy J., de Wit J., Hoshide A.K., Martin G., 2018. Critical factors for crop-livestock integration beyond the farm level: A cross-analysis of worldwide case studies. Land Use Policy 73, 184–194. https://doi.org/10.1016/j.landusepol.2017.12.010

Barreteau O., Bousquet F., Etienne M., Souchère V., D'Aquino P. 2014. Companion modelling: A method of adaptive and participatory research. In : Companion modelling: A participatory approach supporting sustainable development. Etienne, M. (ed.). Dordrecht : Springer, 13-40. ISBN 978-94-017-8556-3. https://doi.org/10.1007/978-94-017-8557-0_2

Speaker: Dr Julie Ryschawy (AGIR, Univ Toulouse, INPT, INRAE, Toulouse, France)

85 How do Community Supported Agriculture in Norway and the UK get members to eat more vegetables and be more content?

There is need for a transition of the food system towards more sustainable cultivation methods and more plant-based diets (Billen et al., 2021; Willett et al., 2020). Community supported agriculture (CSA) may have a positive environmental impact locally and increase vegetable intake among members (Medici et al., 2023). It is a format for provisioning food locally, where consumers to various degrees are involved in the production process. In this study we search to identify factors that have a positive impact on members’ contentment with CSAs and that contribute to increase their consumption of vegetables. We also explore differences between CSAs in Norway and the UK in terms of organisational models and member characteristics.

In collaboration with CSA network organisation in the UK and Norway, an electronic survey with CSA members was performed in the two countries, and the data was analysed as summary statistics and with correlation and regression analyses.

The results show that, compared with the British, Norwegian CSA members participate far more actively in the cultivation and harvesting of the vegetables, and they more often make the prepayment for the whole season. In both countries, CSA membership was perceived to have caused improvements in members’ life quality, physical and mental health, and vegetable intake, corroborating with other studies (Mills et al., 2021; Zepeda et al., 2013). Regression analyses show that members who participated more actively in the CSA, who were concerned about environment when buying food, and who received more of their vegetables through the CSA, were also more satisfied with their CSA and had a stronger perception that their vegetable consumption level has increased as a result of their membership. Members with lower education were more likely to have discovered new vegetables through the CSA. Correlation analyses find that vegetable quality and affordability is associated with higher contentment, and that learning how to cook and grow vegetables through the CSA is associated with higher consumption of and interest for new vegetables.

Overall, the results indicate that CSAs stimulate contentment with organisational models which imply active participation of members. However, despite their more active involvement in the growing process, Norwegian CSA members are not more satisfied with their CSAs than the British. This could be explained by British CSAs high involvement of members in social activities, which might have a similar effect as a more practical involvement. Members’ emphasis on environmental aspects indicates that sustainable production methods are important for CSAs to remain attractive. However, CSAs in both countries must be able to supply good quality and affordable vegetables in sufficient quantities to keep their members happy. For vegetable consumption to increase through CSA membership, it could be beneficial to provide courses on how to grow vegetables, and information about how to cook them.

Billen, G., Aguilera, E., Einarsson, R., Garnier, J., Gingrich, S., Grizzetti, B., Lassaletta, L., Le Noe, J., & Sanz-Cobena, A. (2021). Reshaping the European agro-food system and closing its nitrogen cycle: The potential of combining dietary change, agroecology, and circularity. One Earth, 4(6), 839-850. https://doi.org/10.1016/j.oneear.2021.05.008
Medici, M., Canavari, M., & Castellini, A. (2023). An analytical framework to measure the social return of community-supported agriculture. Agroecology and Sustainable Food Systems, 47(9), 1319-1340.
Mills, S., Furness, E., Clear, A. K., Finnigan, S. M., Meador, E., Milne, A. E., Sharp, R. T., & Bellamy, A. S. (2021). The role of community-supported agriculture in building health and sustainability into UK diets: a mixed methods study. Lancet, 398, 68-68. <Go to ISI>://WOS:000723044300068
Willett, W., Rockstrom, J., & Loken, B. (2020). Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems (vol 393, pg 447, 2018). Lancet, 395(10221), 338-338. <Go to ISI>://WOS:000510860200032
Zepeda, L., Reznickova, A., & Russell, W. S. (2013). CSA membership and psychological needs fulfillment: an application of self-determination theory. Agriculture and Human Values, 30(4), 605-614. https://doi.org/10.1007/s10460-013-9432-z

Speaker: Anna Birgitte Milford (Norwegian Institute of Bioeconomy Research)

263_Milford.pptx

86 Activity analysis through the course-of-action research program: an innovative method for analyzing farmers' practices

Moving towards sustainable and input-efficient cropping systems involves analyzing farmers' practices, particularly those related to managing plant health. Understanding the knowledge they use and the underlying logic guiding their practices (Altieri, 2004) is crucial. Agronomy often focuses on describing and evaluating the technical sequences adopted by farmers but pays less attention to their specific knowledge and implementation methods. Farmers have various ways of assessing their agroecosystem health, using different criteria, indicators, and threshold levels (Toffolini et al., 2016). This diversity is reflected in their choice of diverse agricultural practices to manage crop health.
Therefore, our objective is to specifically analyze how Ivorian cocoa farmers manage cocoa tree health during the implementation of practices. To achieve this, we used the Activity Analysis method from the field of education sciences, specifically the “Course of Action” research program. This program studies human activity in various social domains and situations. A course of action refers to "the activity of a stakeholder in a specific state, actively engaged in a specific physical and social environment, belonging to a specific culture, which is meaningful for him/her, or can be shown, narrated, and commented on by the stakeholder at any moment of its unfolding to an observer-interlocutor under favorable conditions" (Theureau et al., 2003). A stakeholder's activity is defined as the dynamic of asymmetric interactions between him/her and his/her environment, meaning these two parts in this series of interactions do not have the same level of influence. In our case, activity represents the implementation of a farming practice resulting from interactions between the farmer (the stakeholder) and the cropping system (the environment).
The activity analysis methods, as described by Theureau (2010), aim to closely approach the reality of farming practice implementation. They seek to understand the inherent complexity of these practices and highlight key indicators. This approach considers activity as a succession of signs (Theureau, 2006).
In this study, we applied the activity analysis method, specifically self-confrontation and simultaneous, deferred, and interruptive verbalizations, to a sample of eight cocoa-based agroforestry systems—four managed organically and four conventionally—in the Agnéby-Tiassa region of Côte d'Ivoire. These plots differ in associated agrobiodiversity (high or low) and agricultural management intensity (high or low). We hypothesize that cocoa farmers' plant health management practices vary and are influenced by the structure and composition characteristics of the associated agrobiodiversity, whether in an organic or conventional plot. Activity analysis has allowed us to highlight varied rationale explaining the diversity of practices implemented for cocoa tree health management, clearly linked to associated agrobiodiversity. This original method allows us to understand these practices more in detail compared to a classic agronomic diagnosis. This interdisciplinary approach, borrowing from education sciences to adapt a method to agronomic sciences, should lead to the emergence of new knowledge and a better understanding of health management practices. This will be particularly useful, among other things, for contributing to the co-design of innovative and sustainable cropping systems.

References:
Altieri M.A. 2004. Linking ecologists and traditional farmers in the search for sustainable agriculture. Frontiers in Ecology and the Environment, 2 (1) : 35‑42. doi: 10.1890/1540-9295(2004)002[0035:LEATFI]2.0.CO;2.
Astier P., Gal-Petitfaux N., Leblanc S., Sève C., Saury J., Zeitler A. 2003. Les approches situées de l’action : quelques outils. Recherche & Formation, 42 (1) : 119‑125. doi: 10.3406/refor.2003.1833.
Theureau J. 2006. Le cours d’action: Méthode développée
Theureau J. 2010. Les entretiens d’autoconfrontation et de remise en situation par les traces matérielles et le programme de recherche « cours d’action ». Revue d’anthropologie des connaissances, 4 (1) : doi: 10.3917/rac.010.0287.
Toffolini Q., Jeuffroy M.-H., Prost L. 2016. Indicators used by farmers to design agricultural systems: a survey. Agronomy for Sustainable Development, 36 (5) : np. doi: 10.1007/s13593-015-0340-z.

Speaker: Marie-Thérèse Morrisson (Centre de coopération internationale en recherche agronomique pour le développement (CIRAD))

87 Stakeholders’ perceptions of climate change and challenges for grain legume adaptation to future climate in France

INTRODUCTION: In Europe, increasing the area cultivated with grain legumes has been identified as a lever to mitigate and adapt to climate change. However, climate change will also impact these crops (Marteau-Bazouni et al., 2024). It is thus necessary to explore adaptation options to sustain grain legume performances in the context of climate change.
To better design innovations for adaptation, it is important to consider the needs and activities of stakeholders (Beveridge et al., 2018; Cerf et al., 2012). Although several studies have surveyed producers and experts for their perceptions of climate change and adaptation in Europe (e.g., Peltonen-Sainio et al., 2020), no data are available for grain legumes.
The objectives of this study were to assess (i) stakeholders’ perceptions of climate change and its impacts on grain legumes, (ii) the actions they imagine to develop innovations for adaptation, and (iii) the knowledge that is currently available, as well as the knowledge they would need to implement these actions.

MATERIALS AND METHODS: We conducted 32 semi-structured interviews with stakeholders involved in different stages of grain legume value chains in France. Participants were identified with a snowball sampling. First, we selected advisors from 10 regional Chambers of Agriculture to cover a large part of the French territory. Participants were then asked for contacts in other professional sectors: cooperatives and industries (11 participants), extension services (6), and seed breeding and multiplication (5). We analyzed interview recordings to identify stakeholders’ perceptions of climate change and possible adaptation options related to their activities. We then derived profiles of stakeholders based on their perceptions of climate change and adaptation.

RESULTS: A majority of participants reported that climate change has already negatively impacted grain legumes’ performances. They reported a rise in the occurrence of heat stress, milder winters with cold snaps, and an unequal repartition of rain characterized by an increased frequency of drought periods and heavy rains, which represent major constraints for pea, faba bean, and lentil management and performances. The impacts of climate change on biotic pressure (weeds, pests, pathogens), on the frequency of extreme events, and on the interannual climate variability are considered among the main challenges for adaptation. Conversely, the average temperature increase is regarded as an opportunity for species such as soybean, lentil, and chickpea, especially in the northern half of France.
The participants proposed various contributions to climate change adaptation, such as experimenting or supporting the experimentation of agronomic levers, breeding grain legume varieties adapted to changing climate conditions, supporting the introduction of new species, creating value to secure producers’ income in spite of climate variability, and sharing knowledge on grain legume cultivation or climate change. Each profile was associated with different innovations, space and time scales for action, and knowledge needs.

DISCUSSION: Although the participants have observed, tested, and imagined numerous adaptation options, they perceived that climate and technical constraints, as well as sociotechnical lock-ins, limit the effectiveness of these adaptations. Producing and sharing knowledge among the various stakeholders is thus a challenge to support the adaptation of grain legume cultivation to current and future climate. We propose here an original synthesis to gather ideas and identify future research areas.
Our results raise the need for new methods to handle adaptation to climate change, balance short-term and long-term objectives, and establish synergies between researchers and various stakeholders to design effective adaptation strategies for grain legumes.

REFERENCES:
Beveridge, L., Whitfield, S., and Challinor, A. (2018). Crop modelling: towards locally relevant and climate-informed adaptation. Climatic Change, 147(3–4), 475–489. https://doi.org/10.1007/s10584-018-2160-z
Cerf, M., Jeuffroy, M.-H., Prost, L., and Meynard, J.-M. (2012). Participatory design of agricultural decision support tools: taking account of the use situations. Agronomy for Sustainable Development, 32(4), 899–910. https://doi.org/10.1007/s13593-012-0091-z
Marteau-Bazouni, M., Jeuffroy, M.-H., and Guilpart, N. (2024). Grain legume response to future climate and adaptation strategies in Europe: A review of simulation studies. European Journal of Agronomy, 153, 127056. https://doi.org/10.1016/j.eja.2023.127056
Peltonen-Sainio, P., Sorvali, J., and Kaseva, J. (2020). Winds of change for farmers: Matches and mismatches between experiences, views and the intention to act. Climate Risk Management, 27(November 2019), 100205. https://doi.org/10.1016/j.crm.2019.100205

Speaker: Marie Marteau-Bazouni (Université Paris-Saclay, AgroParisTech, INRAE, UMR Agronomie)

88 Co-building organic agriculture expansion scenarios with increased nitrogen autonomy at territorial scale: the case of Morlaix communauté

1/ Introduction

Organic agriculture (OA) has been identified as key strategy in the European Green Deal to increase the agricultural area dedicated to OA from the current 10% to 25%. One of the key challenges to achieve this goal is the careful management and improved circularity of nutrients, particularly nitrogen, which is a limiting factor for the expansion of OA agri-food system¹. Recent papers suggest that focusing on the territorial or landscape level can effectively enhance agri-food system sustainability². Similarly, participatory modelling scenarios have shown promise in designing a more sustainable future for the agri-food system. However, existing frameworks lack the ability to assess the complementarity of OA and conventional agriculture within a territory. Here our analysis aims to co-build scenarios with local stakeholders to expand OA to 30% of total agricultural land. By incorporating insights from local stakeholders into a nitrogen budget model, we assess the consistency of two co-built OA expansion scenarios with increased nitrogen autonomy.

2/ Materials, methods

The study focused on Morlaix Communauté district, a high livestock intensive district in Brittany covering 39 772 ha with 10% OA. Our research was conducted in four steps adapted from the participatory design agroecological pathways methodology designed by ref. ⁴ (Fig. 1). The first step involved assessing the current nitrogen flows of OA by calibrating the ALPHA N-budget model5 using regional agricultural statistics on agricultural productions and land use. Steps 2 and 3 consisted of scenario workshops with 20 territorial stakeholders divided in two groups (representing a wide range of perspectives including dairy, poultry and vegetable farmers, local officials, OA feed producers and water management entities) aiming to reach 30% OA. In steps 3 and 4, we translated qualitative drivers from the stakeholders in quantitative drivers based on existing literature and applied these values in the two scenarios.

Fig 1. Four-step process for participatory modeling of organic agriculture (OA) expansion scenarios (adapted from ref.4)

3/ Results

Our analysis highlights that current OA nitrogen autonomy in Morlaix Communauté stands at only 56%. The territory produces close to 34 kgN·ha-1·yr-1 with 60% of animal products. The main N input is biological nitrogen fixation accounting for 41%., followed by conventional manure for 34%, imported feed for 13%, and atmospheric deposition at 12%. Overall nitrogen use efficiency of OA is around 40%. During the workshops, local stakeholders listed nearly 100 levers to increase OA in the territory. Two third of cited levers primarily address economic and social changes with a significant focus on land use changes and current scattered parcels. The remaining third of these levels enhanced its nitrogen autonomy in case of expansion. These latter levers were used to develop two main scenarios that focus on variations in OA crop and livestock mix, the incorporation of legume crops and the level of integration of crop and livestock mix. These factors all contribute to the circularity of nitrogen in the territory.

4/ Discussion

In both OA expansion scenarios, contrasting pathways are observed to achieve increased nitrogen autonomy levels of 60 and 70%. Livestock plays a pivotal role in these scenarios by effectively balancing nitrogen flows within the system, especially through the use of manure to fertilize OA crops. However, there is a critical contextualized trade-off to consider regarding the livestock density threshold and nitrogen autonomy. We provide concrete examples of agri-food systems scenario transition co-developed with local stakeholders emphasizing the potential enhancements through the integrating other environmental dimensions such as the energy functioning of OA, or phosphorus and carbon flows.

5/ References

1. Barbieri, P. et al. Global option space for organic agriculture is delimited by nitrogen availability. Nat. Food 2, 363–372 (2021).
2. Koppelmäki, K. et al. Nested circularity in food systems: A Nordic case study on connecting biomass, nutrient and energy flows from field scale to continent. Resour. Conserv. Recycl. 164, 105218 (2021).
3. Van Der Wiel, B. Z. et al. Participatory modelling of scenarios to restore nitrogen cycles in a nutrient-saturated area. Sci. Total Environ. 170335 (2024)
4. Duru, M., et al. M. Designing agroecological transitions; A review. Agron. Sustain. Dev. 35, 1237–1257 (2015).
5. Chatzimpiros, P. & Harchaoui, S. Sevenfold variation in global feeding capacity depends on diets, land use and nitrogen management. Nat. Food (2023)

Speaker: Souhil Harchaoui (UMR SAS, INRAE, Institut Agro)

Sensing & data

Conveners: Benjamin Dumont, Sandra Hull

89 Assessing the sustainability of precision nitrogen fertilization strategies for durum wheat: a comparative study of NNI and NDVI map-based approaches

Introduction
Durum wheat, a crucial staple crop, is confronted with escalating fertilizer usage, particularly nitrogen, to meet the surging demands of a growing population. However, the mismanagement of nitrogen to fulfill crop requirements can inflict harm on ecosystems, spark conflicts, and disrupt supply chains. In response to this challenge, precision fertilization technologies, specifically variable-rate fertilization based on satellite imagery, are being explored to optimize nitrogen (N) fertilizer efficiency in no-till durum wheat cultivation.
Materials and methods
Conducted over four consecutive growing seasons, from October 2018 to July 2022, the experiment took place in Asciano, Siena, Italy, on soil maintained under no-till conditions. Sowing was executed using a "disc-type furrow opener Vella VSD3200A No-till seeder". Four N fertilization approaches were assessed: a uniform N rate conventionally calculated, and three variable rates based on Sentinel-2 L2A spectral bands. These variable-rate approaches encompass one utilizing the Nitrogen Nutrition Index (NNI) (Fabbri et al., 2020), a proportional NDVI-based estimate (NDVIH), and a compensative NDVI-based estimate (NDVIL). The treatments were applied according to a strip-plot design in three block. The surface area of the experimental units ranged from 0.27 to 0.4 hectares over the four growing seasons. Analyzed parameters related to grain yield and kernel quality, protein partitioning, and dough rheology (Guerrini et al., 2020). For the four N fertilization strategies, economic analysis was conducted following the methodology outlined in Fabbri et al. (2023). Further, the carbon footprint was assessed in accordance with the ISO 14044:2006 guidelines.
Results and discussion
The study findings indicate that the NDVIL strategy, while enhancing protein and gluten levels, does incur at cost of yield compared to the uniform N rate. Indeed, the application of High-N fertilizer resulted in noteworthy increases in protein, specifically glutenin (Guerrini et al., 2020; Mancini et al., 2024). Conversely, the NDVIL strategy proves advantageous, increasing both grain yield and protein composition compared to the uniform N rate. In contrast, the NNI strategy, based on satellite imagery, demonstrates promising results by significantly reducing nitrogen usage without compromising grain yield or quality. Moreover, the NNI approach optimizes protein partitioning and dough technical properties, essential factors for various end-use applications. Regarding nitrogen fertilizer use efficiency (NfUE), the NNI strategy consistently outperforms other approaches. Notably, among the tested strategies, only the NNI significantly reduces the carbon footprint of cultivation, exhibiting a decrease of approximately 20 gCO2eq per kg of grain produced (-7.6%) compared to the uniform N rate. Furthermore, the economic analysis underscores the advantages of the NNI approach, showcasing lower social costs and higher rates of return compared to alternative nitrogen treatments. This underscores the economic and environmental sustainability of precision fertilization techniques, particularly the NNI strategy, in durum wheat cultivation.
Conclusion
This research not only advances our understanding of how various N treatments impact durum wheat production but also provides valuable insights across multiple dimensions of this intricate relationship. These dimensions encompass not only yield and protein composition but also extend to dough properties and economic considerations. The findings collectively provide valuable insights for the practical implementation of satellite-based N fertilization strategies, emphasizing the potential long-term benefits and sustainability of the NNI approach in promoting precision agriculture for durum wheat cultivation.

References
Fabbri, C., Basso, B., Napoli, M., Dalla Marta, A., Orlandini, S., Martinez-Feria, R.A., 2023. Developing a tactical nitrogen fertilizer management strategy for sustainable wheat production. European Journal of Agronomy 144, 126746. https://doi.org/10.1016/J.EJA.2023.126746
Fabbri, C., Mancini, M., dalla Marta, A., Orlandini, S., Napoli, M., 2020. Integrating satellite data with a Nitrogen Nutrition Curve for precision top-dress fertilization of durum wheat. European Journal of Agronomy 120, 126148. https://doi.org/10.1016/J.EJA.2020.126148
Guerrini, L., Napoli, M., Mancini, M., Masella, P., Cappelli, A., Parenti, A., Orlandini, S., 2020. Wheat Grain Composition, Dough Rheology and Bread Quality as Affected by Nitrogen and Sulfur Fertilization and Seeding Density. Agronomy 2020, Vol. 10, Page 233 10, 233. https://doi.org/10.3390/AGRONOMY10020233
Mancini, M., Guerrini, L., Fabbri, C., Orlandini, S., Napoli, M., 2024. Understanding the impact of within-field Olsen P variation on common wheat production in Olsen P deficient soils. J Agric Food Res 15, 101007. https://doi.org/10.1016/J.JAFR.2024.101007

Speaker: Marco Napoli (Department of Agriculture, Food, Environment and Forestry (DAGRI) - University of Florence)

90 From NDVI to variable nitrogen application map – Precision agriculture

1. Introduction
   In Baden-Württemberg (B-W, Germany) N application for high protein quality winter wheat (E) is commonly split into three application dates: tillering, stem elongation and late booting. Total possible N application amount of a field is defined by B-W N-Düngebedarfsermittlung (N-requirement determination). Farmers in B-W commonly apply homogeneously at first N application date about 30-35%, about 40-45% on second application and the rest at third N application date (of N-Düngebedarfsermittlung total). However, this approach does not take in-field variability into account.
   Identification of in-field variability can be conducted based on normalized difference vegetation index (NDVI) in the form of satellite image-based remote sensing vegetation monitoring. It is expected that “healthy” biomass causes higher reflectance rates in the near infra-red (B08) and high absorption in red (B04) enabling “detection” of biomass with higher chlorophyll content. It is hypothesized that higher N application rates are needed where the index is higher, as it “indicates” good conditions for plant growth.
   For demonstrating a conceptual framework that uses NDVI for developing variable N application maps, free of charge satellite images downloaded with Copernicus Browser (CDSE 2024) were used. NDVI of a specific field was calculated, potential site-specific zones were delineated and the degree of in-field variability, in relative terms depending on NDVI value was quantified. Detailed instructions on downloading satellite images and using QGIS for identifying in-field variability and producing site-specific N application maps can be found in the GitHub repository (https://github.com/memicemir/ndvi_to_variable_N_application)

2. Materials, methods
   In the case of variable N application rates, farmers have to delineate site-specific zones with different yield potential. For this short study only the first N application (at tillering) was tested, where approximately 70 kg N ha-1 can be spread in the field. In the case of site-specific applications, farmers reduce N application amounts in certain site-specific units (with lower yield potential) and apply higher N amounts in areas with higher yield potential without exceeding 70 kg N ha-1 in total. In this study NDVI (Eq.1) was calculated for each site-specific unit (average value of all pixels in one site-specific unit) and used as an indicator of biomass development on 28 February 2021.
   NDVI = (B08-B04)/(B08+B04) (1)
   Because site-specific NDVI was normally distributed in the field, all index values were classified as either low, medium, or high. The NDVI classes were formed by arbitrary splitting min/max range of field NDVI values into three groups with equal intervals.

3. Results
   Figure 1 shows the NDVI index across different site-specific units with three NDVI range categories: low (white), medium (light green), and high (dark green), representing different plant growth potential. Based on the normal distribution of the index, medium category (0.358 ≤ NDVI < 0.423, Figure 1) was set to 70 kg N ha-1 while low and high corresponded to ±20 kg N ha-1, respectively. The ±20 step was used in order to avoid too large differences between min and max N application rates. After translating NDVI index variability into site-specific N applications, the average N amount applied in the field was 68 kg N ha -1.
   Figure1 (insert here!)
   Figure 1 Spatial NDVI index distribution according to three NDVI index categories used to determine N application rates at an early growth state (BBCH 22-25) of winter wheat.

4. Discussion and conclusion
   Depending on the distribution of low, medium, and high NDVI zones, farmers have to be aware of maximum N kg ha-1 allowance. If there are more high-NDVI zones in the field than low (with medium 70), the farmer might end up exceeding the total N allowance limit. It has to be kept in mind that even if the plants are not growing in specific parts of the field, it does not automatically mean that there is no N in the soil or that N is the growth limiting factor.

5. Acknowledgment
   https://diwenkla.uni-hohenheim.de/

6. References
   Copernicus Data Space Ecosystem (CDSE), Modified Copernicus Sentinel data (2024), processed in Copernicus Browser. https://browser.dataspace.copernicus.eu/
   QGIS 2024. QGIS.org, Geographic Information System. QGIS Association. http://www.qgis.org

Speaker: Emir Memic (University of Hohenheim)

91 Assessment of the complementarity between field observations and multispectral UAV imaging for optimized cover crop management in viticulture: towards a comprehensive approach to the functioning of agroecological practices

Introduction
The evolution of agroecological systems introduces greater complexity in cultivated fields, challenging both traditional and modern observational networks and methods. These include remote observations, e.g. aerial data collection, proxidetection, e.g. crowdsourcing, and direct in situ measurements. The digital transition is continually producing vast amounts of data, enhancing our understanding of agroecosystems when used effectively (Ingram and Maye, 2020), both within and surrounding agricultural plots. As a result, the increasing availability of digital tools is transforming the role of on-farm experimentation (OFE) in contemporary agriculture (Lacoste et al., 2021). With this backdrop, this study aims to assess whether there is redundancy or complementarity between field measurements and UAV imaging throughout the growing season, and to determine the efficacy of UAV imaging in the management of service crops in viticulture.

Materials & Methods
An experiment was conducted over three years (2019-2022) at the Domaine du Chapitre (France) on a vineyard plot (Vitis vinifera Syrah), divided into three blocks. The experiment aimed at comparing 6 service crops termination strategies, combining two termination periods (early and at grapevine budbreak) and three termination methods (mowing, roller-crimper, mowing + tillage). Several indicators were assessed to evaluate the water stress (predawn leaf water potential), vigor (pruning weight) of the grapevine, as well as to monitor service crops development through biomass and LAI measurements. In 2021-2022, alongside field measurements, auxiliary data were collected on 10 dates, from service crops emergence to grapevine flowering, using multispectral sensors mounted on a UAV. All the aerial imagery were processed using Agisoft Metashape software. The same products were obtained in the pre-processing step: orthoimage, digital elevation model, digital surface model, normalized digital surface model (nDSM). A series of indicators were calculated, including the geometric characteristics of the vines canopy, the biovolume of inter-row vegetation cover and spectral indices. To assess the quality of UAV-derived indicator estimates, correlation analyses were used to explore the precision and robustness of the relationship between manual measurements and indicators from multispectral imagery. A spatio-temporal complementarity table is used to provide a detailed assessment of data complementarity at different growth stages and to highlight potential correlations and divergences between UAV and direct field indicators.

Results & Discussions
Analysis of the data collected over the three-year experiment revealed a significant complementarity between field measurements and multispectral UAV imagery (Figure 1). We looked at the relationship between field measurements indicators and UAV-derived indicators. For instance, we assumed a strong indicator relating to water stress in vines (predawn leaf water potential vs NDVI or tree row volume). The results showed promising correlations between variations of both manual and UAV-derived indicators. In addition, it was observed that estimates of inter-row vegetation cover biovolume, obtained from the nDSM, closely matched field measurements, thus confirming the accuracy of UAV imagery in estimating vegetation cover crop biomass. To extend this analysis, a spatio-temporal complementarity table was drawn up, enabling a detailed assessment of the interaction between field measurements and data acquired by UAV, depending on the vine block and phenological stage under consideration. The results confirmed the complementary nature of the measurements obtained by different methodologies, but also highlighted the importance of combining these data for accurate and informed farm monitoring and management.

Conclusions
This study illustrated the role of multispectral UAV imagery in refining cover crop assessment and opening new perspectives for cover crop adaptive management in viticulture. As a result, the growing availability of digital tools offers unprecedented prospects for designing new experimental models in agroecology, making it possible to reimagine the role of the OFE and bring out innovative practices for optimized management of cover crops in viticulture. In this perspective, exploring the synergy between advanced digital tools and the Ecosystem Services functional Spatial Unit offers promising horizons for redesigning on-farm spatial experiments.

References
Ingram, J., Maye, D. 2020 What Are the Implications of Digitalisation for Agricultural Knowledge?, Frontiers in Sustainable Food Systems, 4, 66.
Lacoste, M., Cook, S., et al. 2021 On-Farm Experimentation to transform global agriculture, Nature Food. 3, 11–18.

Speakers: Mr Anice Cheraiet (UMR ITAP, University of Montpellier, INRAE, Institut Agro, B.P. 5095, F-34196 Montpellier cedex 5, France), Léo Garcia (ABSys, Univ Montpellier, CIHEAM-IAMM, CIRAD, INRAE, Institut Agro, Montpellier, France)

92 Site-specific mechanical weeding in North-West-Germany

Introduction
Weeds compete with crops for resources such as water, nutrients and light, causing an average yield reduction of 34 % globally (Oerke, 2006). However, weeds also have positive effects, such as providing food and shelter for arthropods (Selfors et al., 2018) and preventing soil erosion (Seitz et al., 2019). Weeds are not evenly distributed in the field, but form patches, so uniform weed management is often unnecessary (Castaldi et al., 2017). Mechanical weeding offers the possibility to reduce herbicides and is commonly used in organic farming. But it has drawbacks, such as damaging or killing crops by hoeing and increasing soil erosion and weed seed emergence after soil disturbance (Seitz et al., 2019). Site-specific weed management (SSWM) is the concept of adjusting management intensity according to the weed species and density distribution within a field. This technique can reduce the negative impacts of weed control. This work analyses approaches of site-specific mechanical weeding in maize in North-West-Germany.

Material and Methods
A field trial was conducted at the research station “Waldhof” of University of Applied Science Osnabrück, in the North-West-Germany, in 2021 and 2022. Two types of decision support were compared with uniform weeding. One is based on the weed cover (WC), and the other on the relative weed cover (RWC). The RWC is the ratio of weed cover to crop cover. For both treatments, three factor levels were tested: WC0.25; WC0.5; WC1.0; RWC0.1; RWC0.2; RWC0.4. Each treatment was repeated four times in randomised order. UAV-based multispectral cameras were used to distinguish between maize, weeds and soil. Different camera systems and algorithms were tested to optimise the workflow. Weed management was applied when the threshold of the treatment was exceeded. A uniform weeding was carried out with torsion harrow, followed by two site-specific hoeing applications. ANOVA with subsequent Tukey test (α = 0.05) was used to identify significant differences.

Results and Discussion
In 2021, higher maize yields and lower weed biomass were observed due to 106 mm more precipitation than in 2022. In both years, there was no difference in maize yield or weed biomass among the treatments. The thresholds of the first site-specific hoeing application were reached by all treatments. With the second site-specific hoeing, only 58 % of the area was hoed on average in 2021, while in 2022, 89 % of the area was hoed. These savings are similar to those reported by other studies (Castaldi et al., 2017; Niemeyer et al., 2024). In 2022, the smaller plants competed less with the weeds, resulting in higher weed growth in the early stage and more thresholds being exceeded. The non-conservative RWC0.4 treatment spared significantly less area, with -100 % and -66.6 % treated area in 2021 and 2022, respectively. For several of the treatments with low thresholds no significant differences to a uniform weeding were observed. The RWC treatments also considered maize growth. With better crop development more weeds could be tolerated and less area needed to be hoed. This study demonstrates the potential of SSWM and the RWC as weed control thresholds to enhance biodiversity and mitigate the negative effects of weeding.

References

• Castaldi, F., Pelosi, F., Pascucci, S., Casa, R., 2017. Assessing the potential of images from unmanned aerial vehicles (UAV) to support herbicide patch spraying in maize. Precis. Agric. 18, 76–94. https://doi.org/10.1007/s11119-016-9468-3
• Niemeyer, M., Renz, M., Pukrop, M., Hagemann, D., Zurheide, T., Di Marco, D., Höferlin, M., Stark, P., Rahe, F., Igelbrink, M., Jenz, M., Jarmer, T., Trautz, D., Stiene, S., Hertzberg, J., 2024. Cognitive Weeding: An Approach to Single-Plant Specific Weed Regulation. KI - Künstliche Intelligenz. https://doi.org/10.1007/S13218-023-00825-6
• Oerke, E.C., 2006. Crop losses to pests. J. Agric. Sci. 144, 31–43. https://doi.org/10.1017/S0021859605005708
• Seitz, S., Goebes, P., Puerta, V.L., Pereira, E.I.P., Wittwer, R., Six, J., van der Heijden, M.G.A., Scholten, T., 2019. Conservation tillage and organic farming reduce soil erosion. Agron. Sustain. Dev. 39. https://doi.org/10.1007/s13593-018-0545-z
• Selfors, L., Werts, P., Green, T., 2018. Looking beyond the jug: Non-chemical weed seedbank management. Crop. Soils 51, 28–53. https://doi.org/10.2134/cs2018.51.050

Speaker: Tobias Reuter (University of Applied Science Osnabrueck)

231_Reuter.pdf

93 From genotypes to cropping system improving soybean yield in relay-cropping under water stress enhanced by cereal competition

Introduction: Relay-cropping is a crop association where the implementation and harvest of the crops is delayed, leading to an asynchronous cycle of development. It enhances land productivity with two separate harvests in a year (Lamichhane et al. 2023). The main constraint of relay-cropping is the competition endured by the second crop (i.e., soybean) from the winter cereal, leading to yield losses that can range from insignificant to over -90 % (Wallace et al. 1996; Sandler et al. 2015) depending on climatic conditions. Soybean's sensitivity to water stress necessitates the development of more resistant genotypes, particularly in the context of increasing drought events and intercropping systems. To advance knowledge in this area, we conducted in situ experiments exploring soybean functional traits responses to relay-cropping and water stress under low irrigation as well as controlled conditions experiments to quantify their hydraulic resistance to water stress.

Materials and Methods: Five years of preliminary trials were conducted in southwestern France, on a farm experienced in soybean cultivation under irrigated conditions. Yields of pure and relay crops and land equivalent ratio (LER) were assessed every year. Two years of field experiments under non-irrigated conditions were performed in northern France of barley/soybean relay-cropping with four soybean contrasted genotypes . Root functional traits (mass ratio, specific length, length density, angle and nodules) were measured at barley harvest and one month after to assess the plasticity of the genotypes to relay-cropping and water stress. In controlled conditions hydraulic traits including vulnerability to embolism and residual transpiration were measured on ten contrasted soybean genotypes to quantify their resistance to drought compared to other crops and the variability among genotypes.

Results: The irrigated trials in southern France demonstrated the productivity potential of relay-cropping with a mean LER of 1.62. The cereal is not impacted by the relay-cropping, while soybean present a mean yield loss of 25 % compared to pure soybean. In northern France field trials, we demonstrated that relay-cropping can exacerbate drought stress and, consequently, competition for water between crops, leading to phenological delay and growth abortion. However, root functional traits like lateral root mean angle and specific root length were higher in relay-cropping. The experiments in controlled conditions showed that the soybean is sensitive to embolism, but the genotypes presented wide variations of resistance to embolism of 1 MPa between the most resistant genotype and the less resistant. Hydraulic segmentation was observed in soybean and petiole was highlighted as a hydraulic fuse, being more vulnerable to embolism.

Discussion: Relay-cropping increases competition for water between both species and impact the performances of the soybean. Irrigation appears as mandatory to allow soybean to sustain the competition with the cereal, specifically during the emergence and vegetative growth as they are critical stages of soybean development in relay-cropping. The soybean genotypes in relay-cropping treatments presented higher root mass ratio from 10 to 32 %. Higher specific roots length and lateral root angle indicated longer, thinner, and vertically oriented roots to favour water acquisition. The highlight of root traits plasticity brings new perspectives to identify and select appropriate genotypes for relay-cropping (Schneider and Lynch 2020). Characterisation of adapted genotypes to relay-cropping requires also to quantify the genetic variability of soybean to drought resistance notably by focusing hydraulic traits. Whereas soybean is sensitive to water stress compared to other crops, the genetic variability allows to select more resistant genotypes. Correlation between embolism resistance and the relative performances of soybean (data from Terre Inovia 2020 to 2022) genotypes shows that this trait offers prospects for improving genotypes.

References:
Lamichhane JR, Alletto L, Cong W-F, et al (2023) Relay cropping for sustainable intensification of agriculture across temperate regions: Crop management challenges and future research priorities. Field Crops Res 291:108795. https://doi.org/10.1016/j.fcr.2022.108795

Sandler L, Nelson KA, Dudenhoeffer C (2015) Winter Wheat Row Spacing and Alternative Crop Effects on Relay-Intercrop, Double-Crop, and Wheat Yields. Int J Agron 2015:e369243. https://doi.org/10.1155/2015/369243

Schneider HM, Lynch JP (2020) Should Root Plasticity Be a Crop Breeding Target? Front Plant Sci 11:. https://doi.org/10.3389/fpls.2020.00546

Wallace SU, Bacanamwo M, Palmer JH, Hull SA (1996) Yield and yield components of relay-intercropped wheat and soybean. Field Crops Res 46:161–168. https://doi.org/10.1016/0378-4290(95)00009-7

Speaker: Viviane Schell (Institut Polytechnique UnilaSalle, AGHYLE)

145_Schell.pptx

1:00 PM Lunch break

Is agronomy keeping up with digital agriculture? - Simon Cook

Convener: Claas Nendel

ESA2024_keynote_Cook.pdf

94 Is agronomy keeping up with digital agriculture?

Speaker: Simon Cook (Murdoch University)

ESA2024_keynote_Cook.pdf

3:25 PM Coffee break

Poster session #2

Agro-ecological transitions at the landscape and territorial levels: co design

Conveners: Elisa Marraccini, Mateja Slovenc Grasselli

95 Researching with, not for, the farmer in four African countries: the InnoFoodAfrica Project

InnoFoodAfrica was a Horizon 2020 project running from 2020 to 2024, with the aim of improving productivity and sustainability of food systems in Ethiopia, Kenya, South Africa and Uganda. The work-package on crop production practices used Farmer Participatory Research (FPR). Experiments in each country tested the impact of certain inputs on modern cultivars and local landraces, with three iterations. Several (usually pre-existing) teams of 10 – 20 farmers were engaged for work on each crop. The crops were faba bean, teff, maize and orange-fleshed sweet potato (OFSP) in Ethiopia; cowpea, finger millet, amaranth and OFSP in Kenya; cowpea, Bambara groundnut and OFSP in South Africa; and cowpea, finger millet, sorghum and matooke banana in Uganda. Seeds and inputs were provided by the project. The farmers did the work under the guidance of local experts and, importantly, made the decisions on how to proceed based on the outputs of the research. Since communities were involved, eating quality of the harvest was investigated and formed an important part of the decision-making process. In the first iteration, the full factorial of cultivars and inputs, with replicates, was established on 2 – 4 farms. In the second iteration, the number of treatments was reduced, the size of the plots was increased, and several “baby trials” demonstrating favoured combinations of cultivar and input were established on participating farms. The third iteration was a scaling-up phase, with fewer but the best treatments in the replicated experiments and more baby trials.
Both genetics and management contributed to improved yields. The best modern cultivars outyielded landraces 1.2-fold to 5-fold, even with low inputs, and the most effective input packages increased yields by similar margins.
One of the key management factors was sowing in rows instead of broadcasting. This enabled weed control by hoeing instead of hand-weeding, and the application of inputs, such as lime in Ethiopia, to only 25% of the plot. To ease the consistency of row spacing, a farmer in Uganda invented a simple row-marking tool consisting of nails driven into a plank towed by ropes.
Farmers chose which treatments to combine. Manure-fertilized amaranth in Kenya had strong stems, while synthetically fertilized amaranth had large seed heads, so the farmers chose a 50 : 50 blend for the next round, producing plants that both stood well and yielded well. Adding a foliar fertilizer, containing micronutrients, boosted yield further. Wood ash, a traditional seed protectant for finger millet in Kenya, boosted yields in combination with synthetic fertilizer (Figure 1A).
Traditional and modern knowledge conflicted when it came to sowing of Bambara groundnut in South Africa. Culturally, this may not happen until after 15 December, but the climate has changed enough that this is several weeks too late for maximum yield.
Dual-purpose crops were not successful. Amaranth and cowpea leaves are traditional green vegetables, but the best cultivars for vegetable use were not the best for seed production, and leaf harvest set back potential seed yield.
Rhizobium inoculation of faba bean was clearly effective in Ethiopia; that of cowpea in Kenya was less so, suggesting that the soils were deficient in more than just N and that the condition of the inoculum was not optimal.
Eating quality was an important determinant of choices. Nitrogen-fertilized OFSP was almost universally watery and of poor texture, unfertilized being much preferred; and in several cases, the second-highest yielding cultivar of OFSP was preferred over the highest-yielding. One new cowpea cultivar, NaroCowpea-2, was praised by the Ugandan farmers for its excellent flavour, although another often yielded more (Figure 1B). When the faba bean crop was harvested, some of the Ethiopian farmers preferred their landrace, but 6 months later said that the new, 2.5x higher yielding cultivar, was just as good.
The project demonstrated several ways in which yields, profits and nutrition could be raised on farms. Continued access to inputs, such as fertilizers, outside the project is a challenge. It is up to each farmer to decide how to proceed.
Figure 1. Grain yields of (A) two cultivars and a local landrace of finger millet in Kenya, given no fertilizer, wood ash only, synthetic fertilizer only, and the combination; (right), five cultivars of cowpea in Uganda at three sites.

Speaker: Fred Stoddard (University of Helsinki)

Stoddard to Rennes 2024.pptx

96 An evidence mapping of participatory modeling methods to use in agricultural living labs

Introduction
Participatory modeling (PM) is an approach in transdisciplinary research in which stakeholders are actively involved in the modeling process (Halbe et al., 2018). The aim is to improve the accuracy of quantitative models (e.g. hydrological models, yield models)(e.g., Beall et al., 2011; Buchheit et al., 2015) or make qualitative models (e.g. actor networks, decision-making processes)(e.g., Bos et al., 2020; Giordano et al., 2021) more realistic. This can contribute to the improvement of policy measures or management, supports social learning or contributes to a better understanding of values and decisions. Although the goals and tasks of PM overlap with those of real-world laboratory research (Maring et al., 2022; McPhee et al., 2021), we found that to date PM has very rarely been applied in living lab research.

Materials and methods
We analyzed 78 case studies and provide a systematic overview of 17 different methods (such as system dynamics, agent-based modeling, Bayesian networking, social network analysis etc.) and 10 objectives of PM (e.g., improving policies, understanding stakeholder priorities, improving numerical models, improve system understanding, etc.). We show (1) which PM methods were used in transdisciplinary research in the agri-food system and to what extent and in which combination each method was used how frequently, (2) which specific objectives were pursued with which method, and (3) whether correlations existed between individual PM methods and the degree of stakeholder involvement.

Results
Our results give insights into research questions and goals currently explored through PM in the agri-food system. Our results show a clear connection between specific methods and specific goals and highlight methods often used together. We also highlight which methods are applicable towards several goals or only towards specific ones, and show significant differences in how often certain methods have been used in our sample. We also found differences in the level of stakeholder participation by method or pair of methods and will provide descriptions of case studies.

Discussion
We show ways in which researchers can expand their range of skills and institutions can build capacity through targeted methods training or hiring, and which methods appear to be particularly suitable for living lab research due to their particularly strong stakeholder involvement (we plan to describe specific studies from our analysis). Our results also help reviewers evaluate living lab research proposals that include PM methods by providing case study precedents. Ultimately, we intend to help establish PM more firmly as an approach in living lab research, for example in light of the European Partnership Agroecology and the EU mission "Soil Deal for Europe", which aim to greatly expand living lab research in the agricultural sector in Europe.

References
- Beall, A., Fiedler, F., Boll, J., & Cosens, B. (2011). Sustainable Water Resource Management and Participatory System Dynamics. Case Study: Developing the Palouse Basin Participatory Model. In Sustainability (Vol. 3, Issue 5, pp. 720–742). https://doi.org/10.3390/su3050720
- Bos, S. P. M., Cornioley, T., Dray, A., Waeber, P. O., & Garcia, C. A. (2020). Exploring Livelihood Strategies of Shifting Cultivation Farmers in Assam through Games. Sustainability, 12(6). https://doi.org/10.3390/su12062438
- Buchheit, P., Campo, P., Dumrongrojwatthana, P., & Promburom, P. (2015). Companion Modelling for resilient water management: Stakeholders’ perceptions of water dynamics and collective learning at catchment scale. https://api.semanticscholar.org/CorpusID:208133261
- Giordano, R., Máñez Costa, M., Pagano, A., Mayor Rodriguez, B., Zorrilla-Miras, P., Gomez, E., & Lopez-Gunn, E. (2021). Combining social network analysis and agent-based model for enabling nature-based solution implementation: The case of Medina del Campo (Spain). Science of The Total Environment, 801, 149734. https://doi.org/10.1016/j.scitotenv.2021.149734
- Halbe, J., Pahl-Wostl, C., & Adamowski, J. (2018). A methodological framework to support the initiation, design and institutionalization of participatory modeling processes in water resources management. Journal of Hydrology, 556, 701–716. https://doi.org/10.1016/j.jhydrol.2017.09.024
- Maring, L., Ellen, G. J., & Brils, J. (2022). Report on Prioritization of Actor Needs and Criteria for Living Lab / Lighthouse Identification. https://www.soilmissionsupport.eu/fileadmin/inhalte/soilmission/pdf/sms_deliverable_3.4_final.pdf
- McPhee, C., Bancerz, M., Mambrini-Doudet, M., Chrétien, F., Huyghe, C., & Gracia-Garza, J. (2021). The Defining Characteristics of Agroecosystem Living Labs. In Sustainability (Vol. 13, Issue 4). https://doi.org/10.3390/su13041718

Speaker: Dr Toni Klemm (Leibniz-Centre for Agricultural Landscape Research (ZALF) e.V., Germany)

97 DEXiPM Grapevine®: evaluating sustainability in codesigned farming systems in a vineyard watershed

1. Introduction
   Viticulture is facing emerging challenges not only because of the effect of climate change on yield and composition of grapes, but also of a social demand for environmental-friendly agricultural management. Adaptation to these challenges is essential to guarantee the sustainability of viticulture. Grapevine varieties are susceptible to fungal attacks, insects, and wood diseases (Mian et al., 2023). In 2016, French vineyards exhibited a notably high Pesticide Treatment Frequency Index (Fouillet et al., 2023), thereby presenting potential risks to groundwater, air quality, soil integrity, and human health. Transitioning to low-input viticultural systems is urgent. This study uses DEXiPM (DEcision eXpert for integrated Pest Management) to evaluate sustainability across economic, social, and environmental pillars in low-input vineyard systems. The Rieutort vineyard watershed (France, Hérault) serves as a case study, adopting a participatory approach. Interviews with winemakers characterized the area and its pesticide use. A role-playing game was used to design agricultural practice change strategies. DEXiPM Grapevine qualitatively evaluates innovative and virtual cropping systems. Strategies are simulated to assess sustainability and compared with initial situations. This study focuses on DEXiPM Grapevine simulations and results to identify promising sustainable vineyard systems for broader regional adoption.
2. Materials and Methods
   Types of Vineyard Operations Considered: Data from a survey in the Rieutort watershed provided information on 23 vineyards. Four types were considered: HEV-Coop mixed, HEV-Coop 100% PGI, Organic -Saint Chinian, and PDO-Saint Chinian.
   Evaluation of Low-Input Vineyard Systems Sustainability:
   Presentation of DEXiPM Grapevine Tool: DEXiPM Grapevine operates based on a detailed and transparent tree structure, aggregating simple information to estimate complex variables.
   Number of Simulations: Co-designed strategies by experts and local actors were simulated with DEXiPM Grapevine to evaluate their impact at the farm and watershed scales to assess practice changes.

3. Results
   Sustainability of HEV-Coop mixed Strategies: Initial situations showed low environmental, medium economic, and high social sustainability. Co-designed strategies significantly improved sustainability across all pillars.
   Sustainability of HEV-Coop 100% PGI Strategies: Initial situations showed low environmental sustainability. Co-designed strategies improved environmental and economic sustainability but slightly decreased social sustainability (Figure 1A).
   Sustainability of Organic -Saint Chinian- Strategies: Initial situations exhibited high sustainability across all pillars. Co-designed strategies further improved environmental sustainability while maintaining economic and social sustainability.
   Sustainability of PDO-Saint Chinian- Strategies: Initial situations showed medium environmental sustainability and high economic and social sustainability. Co-designed strategies significantly improved environmental sustainability (Figure 1B).

4. Discussion
   DEXiPM Grapevine highlighted modest sustainability improvements, primarily in environmental pillars across all vineyard types. Expert-co-designed strategies showed better sustainability enhancements compared to locally designed ones. Key practice changes included herbicide elimination, cover crop development, and adopting resistant varieties. However, DEXiPM Grapevine only provides qualitative evaluations of system sustainability and does not simulate changes in pesticide content or yield outcomes. Further studies using mechanistic models could provide detailed insights into these aspects.

5. Conclusion Adopting low-impact viticultural practices requires system redesign at various scales. The RippViti project aimed to develop and evaluate pesticide reduction strategies at a vineyard territory scale. This study evaluated environmental, economic, and social sustainability of innovative strategies using DEXiPM Grapevine. Most evaluations showed improved environmental performance without compromising economic and social sustainability. The widespread adoption of proposed agronomic strategies could lead to reduced environmental impacts in vineyard practices.
   Acknowledgments This study was conducted as part of the Ripp-Viti project, supported from 2020 to 2023 by various ministries and the French Biodiversity Office. References are available upon request.

References
Mian, G., Musetti, R., Belfiore, N., Boscaro, D., Lovat, L., & Tomasi, D. (2023). Chitosan application reduces downy mildew severity on grapevine leaves by positively affecting gene expression pattern. Physiological and Molecular Plant Pathology, 125, 102025.
Fouillet, E., Delière, L., Flori, A., Rapidel, B., & Merot, A. (2023). Diversity of pesticide use trajectories during agroecological transitions in vineyards: The case of the French DEPHY network. Agricultural Systems, 210, 103725.
Gary, C., Dubuc, M., Metral, R., & Fortino, G. (2015). DEXiPM Vigne®(version 1.0), un outil pour l’analyse de la durabilité des systèmes de culture viticoles. Manuel des entrées de DEXiPM Vigne®.

Speaker: Prof. Aurelie Metay (Institut Agro Montpellier UMR ABSys)

210_METAY.pdf

98 Unraveling collective experimentation in diversified systems: constructing Ideal Types

The agro-ecological transition confronts the agricultural world, and agronomists in particular, with the need for new, more systemic knowledge on a variety of objects and scales to go towards diversified cropping system (Ditzler 2022). The means that have been implemented for majority crops such as wheat or corn in intensive production systems cannot be deployed for such diversified systems and are not enough to fully equip the transition of agri-food systems (Lacoste et al. 2021). It is therefore necessary to rethink the very means of producing this knowledge. Regarding experimentation as a major mean for knowledge production in agricultural sciences, the most common practices remain those led by an analytical approach, within the researchers’ controlled environment of experimental stations. Other types of experiment are being developed or reconsidered, such as long-term system experiments (eg Longis et al. 2024) or experiments led by R&D with farmers (Salembier et al. 2023), or even experiments carried out by farmers themselves (Catalogna et al. 2022), these types being interestingly characterized by their collective nature. We therefore assume that innovation towards agro-ecological practices is based on more or less complex combinations of these different forms of experimentation and implies more collective and multi-actor dimension. It is through this prism that we have decided to approach experimentation.
In this communication, we analyzed these diverse processes of experimentation in relation with the way they renew knowledge production. We conducted 31 semi-structured interviews with stakeholders from French institutions, including researchers, advisors from chambers of agriculture or cooperatives, and leaders of development groups. These stakeholders were selected based on their involvement in experimental projects with inter- or intra-organizational partnerships, and who had a role within the experiment that gave them a comprehensive view of it. These interviews were completed by documentary analysis (mainly meeting reports or experiments’ valorizations) and participation in events such as trial visits. 
The inductive and comparative analysis of these stories of experimentation processes enables us to characterize their diversity according to several axes of interpretation. We in fact identify the diverse intertwining of the “How” (experimental set-ups, in their biophysical and organizational dimensions) and the “Why” (objectives assigned to the implementation of experimentation). This allows us to construct ideal-types (Weber, 1949) of collective experimentations that differently contribute to fuel transitions towards agroecology. This analysis seems to us to be a necessary step towards a better understanding of collective agronomic experiments in the context of diversification of agricultural systems, in order to provide better tools for these complex, multi-stakeholder processes.

References :

Catalogna, Maxime, Muriel Dunilac Dubois, et Mireille Navarrete. 2022. « Multi-Annual Experimental Itinerary: An Analytical Framework to Better Understand How Farmers Experiment Agroecological Practices ». Agronomy for Sustainable Development 42 (2): 20. https://doi.org/10.1007/s13593-022-00758-8.

Ditzler, Lenora Louise Evens. 2022. « Towards Diversified Industrial Cropping Systems? » Phd, Wageningen: Wageningen University. https://library.wur.nl/WebQuery/wurpubs/603203.

Lacoste, Myrtille, Simon Cook, Matthew McNee, Danielle Gale, Julie Ingram, Véronique Bellon-Maurel, Tom MacMillan, et al. 2021. « On-Farm Experimentation to Transform Global Agriculture ». Nature Food 3 (1): 11‑18. https://doi.org/10.1038/s43016-021-00424-4.

Longis, Sandrine, Stéphane Cadoux, Anne-Laure Toupet de Cordoue, Paul Tauvel, Marie Estienne, Pierre Onzon, Françoise Lescourret, Clotilde Rouillon, et Jean-Noël Aubertot. 2024. « Performance of Innovative Cropping Systems Diversified with Oilseeds and Protein Crops: Identification and Resolution of Methodological Issues, Using the Syppre Experimental Network as a Case Study ». OCL 31: 2. https://doi.org/10.1051/ocl/2023022.

Salembier, Chloé, Ane Kirstine Aare, Laurent Bedoussac, Iman Raj Chongtham, Abco de Buck, Nawa Raj Dhamala, Christos Dordas, et al. 2023. « Exploring the Inner Workings of Design-Support Experiments: Lessons from 11 Multi-Actor Experimental Networks for Intercrop Design ». European Journal of Agronomy 144 (mars): 126729. https://doi.org/10.1016/j.eja.2022.126729.

Weber, Max. 1949. Methodology of Social Sciences. The Free Press, Glencoe, Illinois https://doi.org/10.4324/9781315124445.

Speaker: Maïté de Sainte Agathe (UMR Agronomie, Université Paris-Saclay, Agroparistech, INRAE, 91120 Palaiseau, France)

315_desainteagathe.pdf

99 Co-designing through the lens of historical cocoa farming loops to meet current and future needs for sustainable cocoa production in Côte d'Ivoire

Historically, cocoa cultivation in Côte d'Ivoire has moved from the east in the mid-20th century to the west of the country in recent years. The preferred method of cocoa cultivation is on previous forest land use, after clearing and burning the primary forest and girdling the residual trees (Norris et al., 2010). Today, there are 4.4 Mha of cocoa cropping systems cropped by around one million farmers (FAOSTAT, 2024). The average yield per hectare has been declining steadily for the past twenty years, from 700kg of dry beans per hectare to 500kg ha-1. In addition, the market price for chemical or organic inputs such as fertilizers and pesticides, which could help alleviate these problems, is substantially rising, while the investment capacity of farm households is declining. As a result, farmers are using few or no inputs to improve soil quality or combat pests and diseases. Consequently, there is an urgent need to find agroecological solutions that farmers can implement autonomously to restore the support, regulation and production functions of their cocoa plots.
With the aim of identifying innovative practices to address these issues, a participatory design process is currently underway in three villages in Côte d'Ivoire, each located within a different historical cocoa-growing loop. The choice to work in three zones where cocoa farming has been established at different periods was made so as to cover a diversity of issues. These zones are broadly differentiated by the age of the cocoa agroforestry systems (CAFS) found there: from ageing in the east of the country (80 years on average), to mature in the center (25 years on average), to young in the west (10 years on average). Working with twenty farmers in each village, the participatory design process involved three stages. Firstly, an individual agronomic diagnosis of the CAFS is led, in the form of an in situ interview with the farmer. Secondly, fourteen workshops are set up in each village, combining discussions and field work, to (i) define common co-design objectives and (ii) jointly develop technical solutions based on constructive exchanges between farmer and researcher participants. Thirdly, an experimental protocol adapted to the co-design process participants is set up to establish a prototype of these co-designed technical solutions in situ, in the plots of volunteer cocoa farmers who had taken part in the approach.
Problems common to all three villages related to (i) the decline in soil fertility, due to the depletion of soil resources (Tondoh et al., 2015), and (ii) the resurgence of cocoa tree diseases and pests, due to the increase in in food resources for these pests (Rusch et al., 2016) resulting from the significant expansion of cultivated cocoa farms, emerged. Varied local knowledge relative to the pedo-climatic context has led to original solutions, based on agroforestry (naturally-assisted regeneration and nursery seedling production) and the application of organic inputs (biopesticides and compost), which are currently being tested with volunteer cocoa farmers. We compare, analyze and question the different technical choices made between these three zones in relation to the history of cocoa farming and the age of CAFS.
This participatory design approach revealed clear advantages in terms of hybridizing knowledge, and thus enables participants to learn complementary knowledge (Tengö et al., 2014). It is therefore expected to be a driving force in the spontaneous implementation of experiments by farmers to move towards more resilient systems and promote the agroecological transition of cocoa value chains (Alif et al., 2024). However, this approach is still very time-consuming and costly compared with conventional training courses. We question current co-design methods and propose an original way of implementing technical advice with new methods and new tools that would allow upscaling and having an impact on a larger number of targeted stakeholders.

Speaker: Martin Notaro

100 On-farm experiments: farmers and researchers go further together! A synergy to learn about cultivation and postharvest handling of grain legumes in Sweden

1. Introduction

There is a growing interest among farmers and consumers for grain legumes in Sweden and potential in increasing their production and consumption (Röös et al., 2020). This requires better knowledge among farmers and advisors about suitable species, varieties and management practices for different conditions. Since cultivar suitability and management practices including postharvest handling are highly farm-specific, farmers need to gain their own experience (Cristofari et al., 2018). Synergies between the ways of learning of scientists and farmers are highly relevant in this regard. We analysed on-farm experiments designed, managed and evaluated in a collaboration between farmers and researchers. We focus on what farmers and researchers gained from the project and how to facilitate this type of collaboration.

2. Materials and methods

Farmers in southern Sweden were invited by researchers to form a group in a project aiming to increase cultivation of grain legumes for food. Farmers and researchers collaborated on the definition of the design, management and evaluation of experiments. Fifteen on-farm experiments were performed in 2018 and 2019. Researchers performed measurements on the experiments and organised semi-structured interviews and a workshop to present and discuss the experiments. The researchers collected data on farmers’ perceptions of the overall collaboration and critical reflections on the learning process. Data from communications, meetings and field notes were summarised under themes adapted from the framework for farmers’ experiments developed by Catalogna et al (2018).

3. Results and discussion

The farmer-researcher collaboration generated practical knowledge on crop management, strategic knowledge on economic sustainability and knowledge about joint learning.
The experiments on new or relatively new grain legume species like lentil and grey pea often combined several aims related to agronomy: learning about the crop’s growth cycle and potential difficulties, testing intercropping and comparing varieties. With relatively well-known crops like fava bean and yellow pea, the experiments focused on establishment methods and weed control or on establishing a relationship with a retailer for human consumption. We identified multiannual experimental itineraries (Catalogna et al., 2022). Several farmers tested more than one novel practice at a time.
Grain postharvest handling steps such as cleaning and selling were considered by farmers to be integral components of the experiments, especially in relation to trying a new crop or testing the impact of a new practice on postharvest handling (e.g., intercropping). The farmers considered one of the main benefits of on-farm experiments compared to researchers’ typical on-station experiments to be their larger scale and the possibility to have a holistic approach, assessing feasibility of all steps from accessing seeds to selling products.
The experiments provided site-specific knowledge that was also often relevant to other farmers in the group. Using a collective setting to evaluate experiments accelerated the learning process and stimulated interest in new crops and new practices, leading to new experiments. The on-farm experiments combined advantages of ‘pure’ farmer experiments and ‘pure’ researcher experiments (Hansson, 2019), facilitating deeper analysis and understanding of outcomes. The farmers stated that working with researchers and with their peers increased their motivation to test innovative practices and that the external analytical view of researchers had been instrumental for extracting additional knowledge and deriving alternative conclusions. Farmer–researcher collaborations using on-farm experiments can enhance collective learning by combining complementary perspectives throughout the experimentation process.

References

Catalogna, M., Dubois, M., Navarrete, M., 2018. Diversity of experimentation by farmers engaged in agroecology. Agron. Sustain. Dev. 38, 50. https://doi.org/10.1007/s13593-018-0526-2
Catalogna, M., Dunilac Dubois, M., Navarrete, M., 2022. Multi-annual experimental itinerary: an analytical framework to better understand how farmers experiment agroecological practices. Agron. Sustain. Dev. 42, 20. https://doi.org/10.1007/s13593-022-00758-8
Cristofari, H., Girard, N., Magda, D., 2018. How agroecological farmers develop their own practices: a framework to describe their learning processes. Agroecology and Sustainable Food Systems 42, 777–795. https://doi.org/10.1080/21683565.2018.1448032
Hansson, S.O., 2019. Farmers’ experiments and scientific methodology. Euro Jnl Phil Sci 9, 32. https://doi.org/10.1007/s13194-019-0255-7
Röös, E., Carlsson, G., Ferawati, F., Hefni, M., Stephan, A., Tidåker, P., Witthöft, C., 2020. Less meat, more legumes: prospects and challenges in the transition toward sustainable diets in Sweden. Renew. Agric. Food Syst. 35, 192–205. https://doi.org/10.1017/S1742170518000443

Speaker: Dr Nicolas Carton (VetAgro Sup ; Department of Biosystems and Technology, Swedish University of Agricultural Sciences, SLU)

288_Carton.pdf

Improving the nutrient use efficiency

Conveners: Thomas Nesme (INRAE, Chef du département AgroEcoSystem, CS 20032, 33882 Villenave d’Ornon, France), Anne Flore Didelot

101 How can the variety effect in long-term field trials be identified and quantified? A methodological case study

Introduction

Long-term field experiments are a valuable research infrastructure to provide information about plant × environment interaction and nutrient use. The ‘Eternal Rye’ trial at the University of Halle-Wittenberg, Germany, was established by Julius Kühn in 1878 and is the world’s second oldest long-term fertilization trial. During the long history of the trial, the rye varieties changed at irregular intervals (3-50 years). While such changes are unavoidable during the long duration of the trial, they strongly influence the grain yield. In this study, different approaches are compared to identify and quantify the varietal effect over time in order to evaluate the isolated effect of the fertilization treatments.

Materials and Methods

Field trial set-up

The field trial is located in Halle/Saale, Saxony-Anhalt, Germany (https://ltehub.landw.uni-halle.de/eternal-rye). It consists of a continuous cultivation of winter rye with six fertilization treatments. The treatments include the application of farmyard manure, mineral fertilizers (PK, NPK), a combination of mineral and organic fertilization (NPK+FM), organic fertilization, which was ended in 1952 to analyze the after-effects, and an unfertilized control. The treatments are not replicated.
The rye varieties harvested were Saaleroggen (1879-1921), Petkuser (1922-1971), Danae (1972-1974), Dankowski Zlote (1975-1981), Janos (1982-1986), Pluto (1987-1992), Amando (1993-1999), Nikita (2000-2012), and Conduct (2013-2023).

Factorization of grain yield

Factorized grain yields show the deviation of the grain yield of each individual treatment from the annual mean grain yield across all treatments. The factorized grain yield $f_ty$ was calculated as

$f_ty=x_ty/x ̅_y$

where $t$ is the treatment, $y$ is the year, $x_ty$ is the grain yield for a given treatment and year, and $x̅_y$ is the mean grain yield of all treatments in a given year. A value >1 marks a yield higher than the annual average, whereas a value <1 indicates below-average yield. Due to the annual calculation of the mean value, the breeding progress is not considered and the differences between the treatments become clear.

Adjusted grain yield

In another approach the yield of all earlier used varieties is adjusted for the varietal effect by relating it to the yield level of the most recent variety. For each year this adjustment was calculated as

$Y_j=((Y_i-Y ̅_1 )⋅s_2)/s_1 +Y ̅_2$

where $Y_j$ is the adjusted annual yield, $Y_i$ is the annual yield that needs to be adjusted, $Ȳ_1$ and $s_1$ are the mean yield and the standard deviation of the previously used variety across all years, $Ȳ_2$ and $s_2$ are the mean grain yield and the standard deviation of the most recent variety (Chmielewski, 2023).

Linear models

To quantify the influence of both treatment and variety on the grain yield, variance component analyses were calculated, using both fixed and random models. Additionally, linear models were used describe the timely development of grain yield within the period of one variety.

Results and discussion

During periods with no varietal change (e.g. 1878-1921 and 1922-1971) negative trends in grain yield were detectable. With the introduction of new varieties, grain yield increases, due to breeding progress (Laidig et al., 2021). In recent years, the overall level of grain yield increased considerably, even in the completely unfertilized plot.
The factorization allowed to determine the deviation of yield in the six treatments from the annual mean yield. Annual recalculation of the mean yield helps to quantify differences within one specific year.
Adjusting the grain yield of previously used varieties helped to minimize the influence of the variety on the yield, hence it became possible to analyze the long-term effects of the fertilization under the influence of the given meteorological conditions of each year.
A variance component analysis was calculated in random models, eta squared (η²) in fixed models, showing that the influence of variety was smaller than of the treatment but still significant.
With the help of linear models, we aim to find a tool to describe the trend of grain yield development within one variety as well as the increase and change of trend after introducing a new variety to the trial. The analyses are not yet concluded but preliminary results are promising.

References

CHMIELEWSKI, F.-M. (2023) personal communication.
LAIDIG, F., et al. (2021) Long-term breeding progress of yield, yield-related, and disease resistance traits in five cereal crops of German variety trials. Theoretical and Applied Genetics 134, 3805–3827.

Speaker: Dr Karolin Kunz

102 A simulation study to quantify the effect of sidedress fertilisation on N leaching and potato yield

1. Introduction
   Potato farmers are easily tempted to apply high N rates (Vos, 1999). This runs counter to an increasing interest in society to use nitrogen (N) fertiliser efficiently. The conventional fertiliser strategy for potatoes in The Netherlands is a single basal N application shortly before or after planting. Sidedress or split N application has been proposed as an alternative fertiliser strategy that can increase N use efficiency, either by increasing the yield while applying the same amount of N, or by maintaining yield while applying less N (van Evert et al., 2012).
   Most experimental work on sidedress in potato has shown disappointing results, i.e. in most cases no yield gains at same N applied. Most scientific research on sidedress has been experimental, experimenting in 2-3 years, with just 1 or 2 soils and often with only one potato cultivar. The objective of the current research was to more systematically simulate possible yield gains or N saving from sidedress.
2. Materials and methods
   We used a potato crop growth model Tipstar (Jansen, 2008) to simulate for 3 cultivars (early, normal and late maturing), on 2 soils (sandy/clayey) and 38 years of weather data for one location in the Netherlands. For each combination we made pair-wise comparisons:
3. SIDE vs SREC = Sidedress versus single recommended (high) N application – where we hypothesise that sidedressing maintains yields at lower total N applied;
4. SIDE vs SMOD = Sidedress versus single moderate N application – comparing the two at similar total N applied - where we hypothesise that sidedressing increases yields at similar N applied but only in particular conditions: (a) late maturing cultivars, (b) sandy soils and (c) very wet 60 days period after planting.
5. Results
   Figure 1 presents the side-by side comparisons of SIDE vs SMOD at different total sidedress N applied by soil type and cultivar. On the clay soil (left column) orange dots show that at similar total N applied, yields are similar with single N and sidedress N, suggesting that on clay soils, little is to be gained from sidedress application. On the sandy soil (right column) green dots show that given a similar total N applied, yields are in most years similar and in a few years higher with sidedress. Closer analysis of model outcomes confirmed the two main hypotheses and revealed that at same total N applied (a) on sandy soils with wet spring sidedress reduces leaching and increases yield (b) sidedress offers greater benefits for late maturing cultivars in which N has more time to leach below the rooting zone and (c) sidedress offers greater benefits in years with high rainfall in the 60 days after planting, which a 16% probability of occurring in the past 38 years.

Figure 1. Comparing the sidedress fertiliser strategy with the Single Moderate fertiliser strategy (SIDE vs SMOD) in terms of yields and total N applied. Per soil x cultivar x Ntarget (TN) combination 38 dots from simulations in 38 years.
4. Discussion
These results give deeper insight in the underlying causes of when and when not sidedress offers advantages over the conventional single N application. Understanding these causes allows for generalisations to other crops and other conditions. Results suggest that possible benefits of sidedress are strongly dependent on weather, soil and cultivar. The results also show where crop growth models can play a valuable role in research: they allow for analysing crop fertiliser response in a great range of weather conditions which is particularly relevant when potential benefits of a particular fertiliser strategy (like sidedress) occur only rarely, in specific weather conditions like a very wet 60 days after planting.
5. References
Jansen, D.M., 2008. Beschrijving van TIPSTAR : hét simulatiemodel voor groei en productie van zetmeelaardappelen. Plant Research International. https://edepot.wur.nl/27135
van Evert, F.K., Booij, R., Jukema, J.N., ten Berge, H.F.M., Uenk, D., Meurs, E.J.J.B., van Geel, W.C.A., Wijnholds, K.H., Slabbekoorn, J.J.H., 2012. Using crop reflectance to determine sidedress N rate in potato saves N and maintains yield. Eur J Agron 43, 58-67 https://doi.org/10.1016/j.eja.2012.05.005
Vos, J., 1999. Split nitrogen application in potato: Effects on accumulation of nitrogen and dry matter in the crop and on the soil nitrogen budget. Journal of Agricultural Science 133, 263-274. https://doi.org/10.1017/S0021859699006966

Speaker: Dr Pepijn A.J. van Oort (Wageningen Univerisity & Research (WUR))

103 Comparing historical and modern German wheat cultivars: differences in responses to agronomic management and nitrogen

1. Introduction
   Despite the significant improvements in wheat productivity achieved through breeding progress over the past few decades, there remains a pressing need to target even higher yields to fulfil the growing global demand for food. Understanding the response of both historical and modern wheat cultivars to various management strategies is crucial. This understanding can assist in breeding cultivars that demonstrate enhanced productivity and better resource efficiency across diverse environments (Voss-Fels et al., 2019). The current study aimed to evaluate the impact of agronomic practices (plant protection and growth regulators) and nitrogen application rates (0 to 240 kg N ha-1) on both the yield and yield components of historical (1895-1960) and modern (1961-2007) winter wheat cultivars released in Germany.

2. Materials and methods
   The study involved a field experiment over two growing seasons (2018-2019 and 2019-2020), incorporating 16 wheat cultivars released between 1895 and 2007 in Germany. The experiment evaluated three levels of nitrogen fertilizer application (0, 120, and 240 kg N ha-1) and assessed four distinct agronomic practices: chemical-free farming (CF), plant protection (PP, focusing on pest and disease control), growth regulation (GR), and a combination of PP and GR. During each growing season, the main plot consisted of 12 levels, derived from combining four agronomic practices with three nitrogen application rates. The subplots included 16 cultivars, arranged in a split-plot format within a randomized block design that comprised 12 blocks. Sowing and harvesting dates were set to October 11 and July 30 in the first, and October 15 and July 29 in the second season, respectively. The study analyzed several variables, including grain yield, yield components, harvest index, and grain nitrogen yield.

3. Results
   The results of the study indicated that the development of new cultivars, the application of different agronomic practices (APs), and the variation in nitrogen application rates significantly influenced both grain and grain nitrogen yields (Figure 1a). Consistent improvements in yield (+32 %), yield components (grain number, single grain weight and ear number), and harvest index (+25 %) were observed across all treatments in modern cultivars developed post-1960, compared to their historical ones (Figure 1). Grain nitrogen yield in historical cultivars was less responsive to increases in nitrogen application rates compared to modern cultivars (Figure 1a). The yield enhancement observed in modern cultivars is largely due to an increase in both the harvest index and grain number, with changes in thousand-grain weight having a smaller impact (Figure 1b). Increasing the nitrogen application rate to 120 or 240 kg N ha-1 adversely affected the yield and yield components of historical cultivars. In contrast, modern cultivars exhibited significant yield enhancement from increased nitrogen fertilization, especially when coupled with intensive agronomic practices (Figure 1).

4. Discussion
   The study findings showed positive trends in yield and yield components for both historical (1895-1960) and modern (1961-2007) cultivars when management was intensified. However, substantial improvements were observed only in the modern cultivars. Growth variables of historical cultivars showed more enhancement with the application of growth regulators, whereas modern cultivars exhibited greater improvements due to plant protection. Nevertheless, both types of cultivars demonstrated a synergistic response when growth regulators and plant protection were combined. The comparison between the effects of N application rates and agronomic practices (APs) revealed that the impact of N on yield and yield components was considerably greater than that of APs. This predominant influence of N application rates on long-term yield trends of various crop species has also been observed in other environments, including France (Schauberger et al., 2018).

Figure 1. The percentage change in grain and nitrogen yields across various agronomic practices and nitrogen application rates compared to the control treatment for historical (1895-1960) and modern (1961-2007) cultivars (a). The trend of harvest index, thousand grain weight, grain number, and ear number for cultivars released before and after 1960 (b). Each small gray point and large point indicate the mean of a variable per growing season and the median of cultivars across treatments.

References
Schauberger, B., et al., 2018. Yield trends, variability and stagnation analysis of major crops in France over more than a century. Scientific reports 8, 16865.
Voss-Fels, K.P., et al., 2019. Breeding improves wheat productivity under contrasting agrochemical input levels. Nature plants 5, 706–714.

Speaker: Ehsan Eyshi Rezaei (Leibniz Centre for Agricultural Landscape Research (ZALF))

104 A semi-mechanistic phosphorus module for the STICS model: formalization and multi-site evaluation on maize in temperate area

1. Introduction
Crop phosphorus (P) nutrition is one of the key sustainability challenges of the 21st Century (Cordell and White, 2014). Crop models are pertinent tools to study and manage phosphorus in agro-ecosystems. However, P modelling is suffering a delay as compared to nitrogen and carbon. A major reason of this delay is the difficulty in formalizing a semi-mechanistic model that predicts adequately the temporal evolution of soil P availability and crop uptake (Das et al. 2019) as well as crop P nutrition status and the feed-back of a P shortage on crop growth.
2. Material, methods
We coupled the STICS crop model (Beaudoin et al. 2023) with a P module based on the FUSSIM-P model (Mollier et al. 2008). The P module is composed of several sub-modules which simulate crop P demand and partitioning, soil P availability and crop P uptake. A major originality of this work is that it relies on soil solution P concentration and P sorption curves (Morel et al. 2021) to simulate soil P availability and critical P dilution curves to simulate crop P requirement.
We evaluated the model against a dataset coming from four field trials having deficient to excessive plant-available soil P, located in different site in France mainland. The trials consisted of fertilizing maize with a mineral fertilizer at three application rates (P0, P1, P2), corresponding to no P added or P added at an equivalent to one or two times crop outputs. Model predictions of both crop P uptake and plant growth indicator (yield, LAI, and biomass) were evaluated both graphically and using statistical indicator such as Nash–Sutcliffe efficiency (EF) or root mean square error (RMSE).
3. Results
The model has shown great capabilities in predicting P uptake both dynamically and at the end of the cropping season for the whole dataset (EF >0.75). The model have satisfactory predictions of crop biomass accumulation (EF >0.5) and leaf area index. When considering each fertilization level separately, the evaluation has shown that the model had predicted the fertilized treatments better than the non-fertilized one (Respectively an EF of 0.73, 0.75 and 0.64 for P2, P1, and P0). The evaluation of the latter remains nonetheless satisfactory for both P uptake and plant growth.
4. Discussion
The good performance of the model is promising as they show that the model is sufficiently robust to simulate maize P uptake across a range of soil P availability under contrasting temperate climatic conditions. Despite the relative simplicity of the model that does not account for all rhizosphere mechanisms, it seems able to behave well even under low level of P under the considered conditions. The fact that the model predicted the fertilized treatment better than the non fertilized treatment raises however the question of model performance under conditions of more severe P shortage or even more lower soil P availability status (e.g. in tropical soils). Further validations on different crop species and soil and climatic conditions are therefore needed.
5. References
Beaudoin N, Lecharpentier P, Ripoche-Wachter D, et al (eds) (2023) STICS soil-crop model: Conceptual framework, equations and uses. éditions Quae
Cordell D, White S (2014) Life’s Bottleneck: Sustaining the World’s Phosphorus for a Food Secure Future. Annual Review of Environment and Resources 39:161–188. https://doi.org/10.1146/annurev-environ-010213-113300
Das B, Huth N, Probert M, et al (2019) Soil phosphorus modeling for modern agriculture requires balance of science and practicality: a perspective. Journal of Environmental Quality 48:1281–1294. https://doi.org/10.2134/jeq2019.05.0201
Mollier A, De Willigen P, Heinen M, et al (2008) A two-dimensional simulation model of phosphorus uptake including crop growth and P-response. Ecological Modelling 210:453–464. https://doi.org/10.1016/j.ecolmodel.2007.08.008
Morel C, Plénet D, Mollier A (2021) Calibration of maize phosphorus status by plant-available soil P assessed by common and process-based approaches. Is it soil-specific or not? European Journal of Agronomy 122:126174. https://doi.org/10.1016/j.eja.2020.126174

Speaker: Alain Mollier (UMR1391 ISPA, INRAE, Bordeaux Sciences Agro, Villenave d’Ornon, France)

88_Mollier et al - 18thESA.pdf

105 Seasonal partitioning of dry matter and nitrogen of a model perennial grain (Thinopyrum intermedium)

Thinopyrum intermedium subsp. intermedium is currently proposed as a perennial grain crop. This crop is multifunctional by providing grain for human consumption, forage for livestock and multiples ecosystem services thanks to its year-round soil cover and its extensive root system. In comparison to annual crops, Th. intermedium prevents nutrient leaching (Jungers et al., 2019) or enhances soil biodiversity (Förster et al., 2023). However, the allocation of resources to grains is low with a nitrogen harvest index ranging from 20 to 50% (Fagnant et al., 2024). This work aims to quantify the proportion of dry matter and nitrogen (N) allocated within the different above- and belowground plant parts during an entire growing season. This first characterization of the N uptake across plant tissues could represent a preliminary step to improve Th. intermedium through crop breeding or field management. In this study, we used two experimental field with similar soil types located in the experimental farm of ULiège – Gembloux Agro-Bio Tech, Belgium, during the cropping year of 2022 representing the first and the third cropping year of the fields. Th. intermedium seeds originated from the fifth cycle of selection of the Land Institute (Kansas, USA). Biomass of the different plant parts (i.e., leaves, stems, spikes, stem bases, rhizomes, and roots) were sampled at specific phenological stages and their N concentrations were measured. The total aboveground biomass increased until grain maturity and ranged from 13 to 18t of DM ha-1. Within the aboveground biomass, stem bases represented an important proportion accounting from 30 to 54% during the reproductive phase. The belowground biomass sampled until 15cm deep increased until the flowering or the grain maturity and ranged from 4 to 5t of DM ha-1 at grain maturity. Rhizomes only represented 4 to 21% of this belowground biomass and were initiated at the flowering during the establishment year. Root biomass of Th. intermedium in third year halved between the flowering and the autumn vegetative stage. Concerning N allocations, N amount within stems and leaves decreased at the end of the growing season, that wasn’t transferred within spikes. An exception was observed for plants in the establishment year with a weak increase (i.e., 10 kg of N ha-1) of the spikes’ N amount from the flowering to the grain maturity. The N amount within stem bases and rhizomes slightly increased from the flowering to the autumn vegetative stage. Roots’ N amount stayed constant for plants in the establishment year and decreased from the flowering to the autumn vegetative stage for plants in the third year. This led to a loss of N within the whole plant of 56 kg of N ha-1, that was not observed during the establishment year. The first year represented a phase of field establishment of the crop, where the N and dry matter allocations during the growing season increased within perennial and reproductive organs. By contrast, for a crop in the third production year, we observed a decrease of root biomass accompanied by a decrease of the whole plant N at the end of the growing season, indicating no efficient nutrient recycling through translocation to perennial organs. The release of N-rich root exudates or root tissue turnover could lead to an influx of organic N in the soil, that was suggested by Dobbratz et al. (2023) for Th. intermedium from the grain maturity to the autumn regrowth.

Dobbratz, M., Jungers, J.M., & Gutknecht, J.L.M. (2023). Seasonal Plant Nitrogen Use and Soil N pools in Intermediate Wheatgrass (Thinopyrum intermedium). Agriculture, 13(2), 468. https://doi.org/10.3390/agriculture13020468
Fagnant, L., Duchene, O., Celette, F., & Dumont, B. (2024). Maintaining grain yield of Th. intermedium across stand age through constant spike fertility and spike density: Understanding its response to various agronomic managements. European Journal of Agronomy, 152, 127038. https://doi.org/10.1016/j.eja.2023.127038
Förster, A., David, C., Dumont, B., Dimitrova Mårtensson, L.M., Rasche, F., & Emmerling, C. (2023). Earthworm populations and diversity under annual and perennial wheat in a North to South gradient in Western Europe. European Journal of Soil Biology, 119. https://doi.org/10.1016/j.ejsobi.2023.103561
Jungers, J.M., DeHaan, L.H., Mulla, D.J., Sheaffer, C.C., & Wyse, D.L. (2019). Reduced nitrate leaching in a perennial grain crop compared to maize in the Upper Midwest, USA. Agriculture, Ecosystems & Environment, 272, 63–73. https://doi.org/10.1016/J.AGEE.2018.11.007

Speaker: Pierre Aubry

106 The current state of applying agroecosystem models across large areas

Introduction
Climate change and other societal targets require strategic decisions in agriculture, at different levels of organisation and spatial context. Process-based simulations models support such decisions by making relevant processes graspable to the stakeholders that formulate a large range of different questions. Many of those questions require model simulations in a larger spatial and temporal context, which in turn generates a number of technical challenges for the model application, including the execution of a vast number of simulations in short time, and suppling relevant data to the models. This presentation gives an overview of where we currently stand in answering questions on crop yield predictions and projections and related carbon sequestration, nitrate leaching, greenhouse gas emissions and water consumption at large spatial and varying temporal scales.
I am using the MONICA agroecosystem model as an example to demonstrate different use cases for data being supplied through remote sensing and artificial intelligence, and the background of the CASSIS simulation infrastructure to run big-data projects. For the first, I will be highlighting several remote sensing activities that aim at supplying input information for (i) initialisation, (ii) driving and (iii) testing the model. These include satellite-based crop type identification (e.g. Blickensdörfer et al. 2022), detection of irrigation events (e.g. Ghazaryan et al., under review) and sowing dates (Main-Knorn et al., in preparation), and high-resolution information of soil properties and groundwater levels accessible to crops. For the second, I will be introducing the CASSIS simulation infrastructure and its unique security philosophy, implemented using Object Capabilities. The CASSIS simulation infrastructure (Berg-Mohnicke, M. and C. Nendel, 2022) supplies all required data for large-area simulations to the simulation model at a press of a button, which makes the application of models for regional to continental research questions much more comfortable.
Presented use cases include climate change outlooks on crop production for the German government, contributions to the greenhouse gas emission inventory of the Czech Republic, upscaling of rewetting scenarios for drained grassland and the quantification of irrigation water use for crop production in Brandenburg, Germany.

References
Berg-Mohnicke, M. and C. Nendel (2022): A case for object capabilities as the foundation of an environmental model and simulation infrastructure. Environ. Model. Softw. 156, Article 105471.
Blickensdörfer, L., M. Schwieder, D. Pflugmacher, C. Nendel, S. Erasmi and P. Hostert (2022): Multi-year national-scale crop type mapping with combined time series of Sentinel-1, Sentinel-2 and Landsat 8 data. Remote Sens. Environ. 269, Article 112831.
Ghazaryan, G., S. Ernst, F. Sempel, and C. Nendel (under review): Field-level irrigation mapping with integrated use of optical, thermal and radar time series in temperate regions. Int. J. Appl. Earth Obs. Geoinf.
Main-Knorn, M., L.A. Flores, G. Ghazaryan and C. Nendel (in preparation): Crop phenology assessment with multiscale and multisource time series. Remote Sens. Environ.

Speaker: Claas Nendel (Leibniz-Centre for Agricultural Landscape Research (ZALF))

232_Nendel.pptx

Increasing biodiversity for improving resiliency of farming systems

Conveners: Christine Bissuel, Maria Giovanna Sessa

107 Nitrogen uptake of maize, wheat, faba bean, and pea in strip intercropping in the Netherlands

Introduction
Relay strip intercropping with maize has been well studied in China (Li et al., 2020). This system performs well in conventional high-input agriculture partially due to complementary light capture. However, environmental policies aiming at reducing N leaching require reduced N input. In Europe, intercropping has mostly been done by combining cereals and legumes in organic farming in alternate-row or mixed designs (Bedoussac and Justes, 2010), but the absolute yield gain is unstable and constrained due to limited N fertilizer (Li et al., 2020). We here explore the responses of N uptake of cereals and legumes in strip intercropping when applied with moderate species-specific N fertilization, and how these compare to intercrops of two cereals or two legumes.

Materials and Methods
Field experiments were done in 2018 and 2019 in Wageningen, the Netherlands. We compared above-ground N uptake (kg N ha^-1) of maize (“LG30.223”), wheat (Triticum aestivum, “Fanfare”), faba bean (Vicia faba, “Nobless”), and pea (Pisum sativum, “Astronaute”) in six bi-specific intercrops and four sole crops. Intercrops involving maize were relay systems, with maize sown and harvested later than the companion species. Intercrops without maize were nearly simultaneous systems, wherein the component species had the same sowing dates and similar harvest dates. Sowing delay in relay intercrops in 2018 and 2019 were 45 and 37 days respectively, creating differences in temporal complementarity. Total N application was 170 kg N ha^-1 in maize, 125 kg N ha^-1 in wheat, and 20 kg N ha^-1 in faba bean and pea.

Results
N uptake of maize relay-intercropped with wheat or pea was higher than that of sole maize, but only in 2018, the year with greater temporal complementarity between species (less overlap of growing periods). The early-sown species took up more N in the relay intercrops than in sole crops. Combining cereals and legumes in simultaneous intercrops did not improve N uptake of either species compared to sole crops. Thus, relay intercropping with sufficient temporal complementarity allowed an improved N uptake while simultaneous intercropping did not.

Discussion
Temporal complementarity improves resource capture in intercrops compared to sole crops (Yu et al., 2015). The early-sown species in relay intercrops benefits from improved access to light and soil resources due to the initial absence of a competitor species in the neighbouring strip. The late-sown maize required larger temporal complementarity to achieve higher N uptake than sole maize. Unlike high-input intercrops reported in China (Li et al., 2011), our cereals hardly had extra access to soil N remaining in legume strips, as the small amount starter fertilizer was fully taken up during legume establishment. In cereal/legume simultaneous intercrops conducted in organic farming, the mixed or alternate-row design allows a high degree of interaction between component species (Jensen et al., 2020). In our strip intercrops, interaction between conspecific species increased, which likely diminished the advantage of complementary N uptake. We conclude that in strip intercrops with moderate fertilization, complementary N uptake was strongly associated with temporal complementarity.

References
Bedoussac, L., Justes, E., 2010. The efficiency of a durum wheat-winter pea intercrop to improve yield and wheat grain protein concentration depends on N availability during early growth. Plant Soil 330, 19–35.
Jensen, E.S., Carlsson, G., Hauggaard-Nielsen, H., 2020. Intercropping of grain legumes and cereals improves the use of soil N resources and reduces the requirement for synthetic fertilizer N: A global-scale analysis. Agron Sustain Dev.
Li, C., Hoffland, E., Kuyper, T.W., Yu, Y., Zhang, C., Li, H., Zhang, F., van der Werf, W., 2020. Syndromes of production in intercropping impact yield gains. Nat Plants 6, 653–660.
Li, C., Li, Y., Yu, C., Sun, J., Christie, P., An, M., Zhang, F., Li, L., 2011. Crop nitrogen use and soil mineral nitrogen accumulation under different crop combinations and patterns of strip intercropping in northwest China. Plant Soil 342, 221–231.
Yu, Y., Stomph, T.J., Makowski, D., van der Werf, W., 2015. Temporal niche differentiation increases the land equivalent ratio of annual intercrops: A meta-analysis. Field Crops Res 184, 133–144.

Speaker: Dr Bei Dong (Wageningen University & Research)

108 GRAAL - Management of a permanent cover crop by mowing between the rows of a main crop

1. Introduction
   The current societal, political, and regulatory context is leading farmers to search and develop low-input cropping systems based on agroecological levers. Sowing a permanent cover crop, usually legumes, in organic arable farming systems is an interesting lever for (i) increasing the quantities of N entering the system and which can be used by cash crops (Amossé et al., 2014; Guiducci et al., 2018), (ii) better managing weed flora, through better use of space and increased competition (Amossé et al., 2013), (iii) improving soil fertility (Duchene et al., 2017; Nyawade et al., 2019). One of the major difficulties lies in the management of the permanent cover in cash crops, to prevent it from competing too much with the crop and to provide the targeted services (Verret et al., 2017). To achieve these objectives, an inter-row mowing technique based on precise satellite guidance has been developed thanks to a collaboration with an agricultural machinery manufacturer. This technique was tested on different plots and in different production contexts during the years 2021-2023. The aim of this study is to draw up an initial assessment of the agronomic performances obtained, the difficulties encountered and the levers identified to overcome them.

2. Materials and Methods
   The experiments were carried out at 5 experimental sites in France, covering a wide range of agropedoclimatic conditions. On each site, different types of permanent cover were studied (alfalfa, trefoil, clover and sainfoin) and sown between the rows of cash crops with a width of 30 cm. A cash crop control without permanent cover was also established. The cover crops were managed by regular mowing, with 2 to 3 cuts during the cash crop cycle.
   Agronomic monitoring consisted of regular measurements of mineral N residues, measurements of the biomass of ground cover returned to the soil and all the components of cash crop yields. In order to collect feedback from the various experimentation managers, interviews were carried out and provided a better understanding of the difficulties encountered in implementing the practice.

3. Results and Discussion
   Over the two cropping seasons, difficulties were encountered in implementing the practice of regular mowing of perennial legumes. For all the sites, grain cereal yields in treatments with one or two years old perennial cover were 2 to 25 q/ha lower than those obtained in the controls. These results can be explained by strong and rapid competition from perennial cover crops, poorly managed in particular by (i) difficulties in accessing mowing equipment at the right time, (ii) weather conditions that did not always allow the mower to be used at the right stage, or (iii) poor positioning of crops when sowing. However, protein levels improved overall, partly because of the lower yields. Furthermore, the performance obtained varies between species, with alfalfa phenotypes better adapted to this type of management.
   Despite the difficulties encountered, a number of lessons can be learned and a multi-criteria analysis will enable us to dentify the positive and negative effects obtained, and to formalise the obstacles and levers to the implementation of this practice. Many organic farmers and researchers are interested in the results of the GRAAL project (funded by the French Ministry of Agriculture). Overcoming the technical difficulties encountered could mean that managing a permanent cover crop by mowing the inter-row could become a practice that promotes the agro-ecological transition of farming systems.

References
Amossé, C., et al., 2013. Relay-intercropped forage legumes help to control weeds in organic grain production. European Journal of Agronomy 49, 158-167.
Amossé, C., et al., 2014. Contribution of relay intercropping with legume cover crops on nitrogen dynamics in organic grain systems. Nutrient Cycling in Agroecosystems 98, 1-14.
Duchene, O., Vian, J.F., Celette, F., 2017. Intercropping with legume for agroecological cropping systems: Complementarity and facilitation processes and the importance of soil microorganisms. A review. Agriculture Ecosystems & Environment 240, 148-161.
Guiducci, M., et al., 2018. Sustainable management of nitrogen nutrition in winter wheat through temporary intercropping with legumes. Agronomy for Sustainable Development 38.
Nyawade, S.O., et al., 2019. Controlling soil erosion in smallholder potato farming systems using legume intercrops. Geoderma Regional 17.
Verret, V., et al., 2017. Can legume companion plants control weeds without decreasing crop yield? A meta-analysis. Field Crops Research 204, 158-168.

Speakers: Amélie CARRIERE (ARVALIS), Jérôme LABREUCHE (ARVALIS), lionel alletto (INRAE)

109 Tailoring crop diversification strategies to seasonal rainfall can increase crop yields and land use efficiency

Introduction

Crop diversification is widely promoted as a sustainable intensification strategy due its positive effects on the land use efficiency (LUE) of crop production and its contribution to ecosystem services. Yet, such effects are highly variable, and an increase in LUE can mask decreases in individual crop yields. This can be a problem for farmers, who may value each crop differently. Variability in both LUE and individual crop yield translates into uncertainty for farmers that, alongside land and labour constraints, may discourage adoption of diversified systems.

To reduce this uncertainty, a better understanding is needed of how crop diversification strategies respond to the environment in which they are implemented. In this study, we investigated how yields of maize and legume crops and LUE varied along a rainfall gradient under different diversification strategies on smallholder farms in Zambia. We aimed to determine whether one diversification strategy consistently outperformed others, or whether different strategies should be recommended for regions with different growing season rainfalls.

Materials & Methods

We used mixed modelling to explore three years of data (2021-2023) from an on-farm trial network comprising 29 farms spread across two communities of Zambia’s Eastern Province and two communities in Southern Province. These three years and four communities (12 site-years) provided a gradient of rainfall in the growing season from 448 mm to 1034 mm.

Five cropping systems were tested on each farm, a maize monoculture (the control) and four maize-legume diversification strategies: a rotation, an alternate row intercrop, a two-row strip intercrop, and a four-row strip intercrop. All diversification strategies were managed under conservation agriculture (CA). However, the maize monoculture and the maize-legume alternate-row intercrop were also tested with conventional tillage practices. The diversification strategies followed an additive design, so that the same maize plant population of 44,444 plants/ha was adopted for all cropping systems.

Results

Seasonal rainfall influenced the response of both maize and legume yields to different diversification strategies (P<0.05), but had a stronger effect on legume yields. In drier site-years (<700mm rainfall), legume yields aligned with a gradient in the intensity of shading from maize: highest in alternate row intercrops, intermediate in the strip intercrops, and lowest in the rotation. This suggests that in dry conditions, the shading effect of maize modified the microclimate to the legume’s benefit (perhaps reducing heat and evaporation), outweighing the effect of interspecific competition.

Maize appeared to be more sensitive to competition for water. In drier site-years, it yielded lowest in the four-row strip crop, where maize plants are grown more densely within the strip (50cm between rows) leading to higher intraspecific competition. Yields were highest in the rotation, where maize is not tightly spaced (90cm between rows) and does not compete with legumes, but can benefit from their residual effects. Maize was also affected by soil preparation: in both the monoculture and alternate row intercrops, maize yielded relatively more under CA practices in drier site-years, but in wetter site-years, yields were equal (in the monoculture) or better (in the intercrop) under conventional practices.

In terms of the LUE of each cropping system (considering both crops), the alternate row intercrop (under CA only) and the two-row strip crop had higher land equivalence ratios (LER) than other diversification strategies in drier site-years, while the four-row strip crop had a higher LER in wetter site-years. The rotation had a lower average LER than all intercropping systems due to each crop only being present every other year. This difference further increased in dry site-years due to relatively lower legume yields in the rotation.

Discussion

Eastern Province typically has higher growing season rainfall (approx. 800mm) than Southern Province (approx. 600mm), so the four-row strip intercrop would be recommended for Eastern and the two-row strip intercrop or alternate row intercrop (under CA) for Southern. Across Zambia, maize is typically preferred as the staple crop, but legumes offer a richer source of protein and have a higher market price. Overall, our results suggest that tailoring the choice of crop diversification strategies to the expected growing season rainfall (using long-term averages and seasonal forecasts) could be a win-win for yields of both crops.

Speaker: Chloe MacLaren (Swedish University of Agricultural Sciences (SLU) & CIMMYT Zimbabwe)

110 On the economics of crop rotation diversification: valuing pre crop and cropping system effects, and accounting for opportunity costs

Introduction
Crop diversity in general, and crop rotation diversity in particular, is a key principle in the design of agro-ecological cropping systems for arable crops. Since economic motives are of primary interest for farmers, assessing and analyzing the economic return of crop production diversification is essential for convincing farmers to consider diversified cropping systems for adoption as well as for identifying key elements to be improved in the diversified cropping systems that are currently proposed or developed.

Defining and analyzing the economic value of crop rotation diversification
This article presents a simple approach for assessing and analyzing the economic value of crop rotation diversification. This approach relies on basic economic calculus and on data that describe the technical performances of crop rotations with various degrees of diversity in comparable production conditions.

Pre crop effect value, cropping system effect value and opportunity cost
The economic value of a diversification crop can usefully be decomposed into the sum of three components: the value of the pre crop effects, the value of the cropping system effects and, finally, the opportunity value – benefit or cost – of producing the diversification crop. The last component is purely economic while the two others value the agro-ecological effects of crop rotation diversification.
The proposed approach is illustrated by means of an application considering the insertion of pea in a typical cereal-based rotation, a topic of special interest in the EU owing to the current EU dependence on imported protein for feed production and to the benefits brought by inserting legumes in cereal based production systems.
Simple sensitivity analysis techniques, based on basic calculus, are also shown to be very useful for assessing the effects of the wide variety of components of the economic value of crop diversification. Our case study highlights the effects of the yield of pea and of the prices of fertilizers and crops on the value of pea as a diversification crop.

Concluding remarks
More generally, our investigations for gathering data for applying our approach also revealed significant information lacking, especially for describing the effects of cropping system diversification on yield and chemical input use levels. Documenting these effects is crucial for assessing the economic benefits and costs of crop diversification for farmers. These observations certainly calls for agronomists to pay more attention to the economic features related to their research topics and for economists to better account for the agronomic features of the questions they address when they consider agricultural production practices.

Speaker: Alain Carpentier (INRAE)

111 Temperate silvopastoral systems promote nitrification stability in the context of climate change: a case study in Brittany, France

Extreme weather events, such as extreme rainfall and flooding events, are expected to increase in frequency and intensity. Such events are known to disturb major biogeochemical cycles such as the nitrogen (N) cycle (Greaver et al. 2016). As a result, N losses from the agroecosystem to the environment will increase, leading to the alteration of soil, air, water, and biodiversity. Hence the adoption of biodiversity-based practices has gained attention as a way to increase internal regulations that limit N losses. By combining trees and grasslands, silvopastoral agroforestry is adopted in temperate regions with high livestock densities as a solution to prevent N losses while providing other ecosystem services. However, little is known about the regulation of the N cycle in temperate silvopastures, especially under extreme rainfall and flooding events (Kim et Isaac 2022). Here, we present recent results obtained on nitrification, a key process involved in the regulation of N losses, and its stability under flooding stress in two silvopastoral systems (hedgerow versus alley-cropping) of Brittany, France.

Nitrification potential and stability were assessed ex situ for soils sampled at three distances from the trees (0.5, 1.5 and 10m) and for two silvopastoral systems (hedgerow and alley-cropping). Nitrification potential was first measured in stress-free conditions and was explained by variables related to vegetation, soil physicochemical properties, and soil organisms (Mettauer et al. 2023). Then, the resistance and resilience of nitrification potential were measured immediately after four weeks of flooding stress and four weeks after the end of the stress, respectively. Resistance and resilience were considered as proxies of nitrification stability, which was explained by soil physico-chemical properties using a multigroup latent structural equation modeling (ML-SEM). The used ML-SEM enabled to test the causal relations that may explain nitrification stability and examine if similar causal patterns are shared among the distances to the trees and the silvopastoral systems.

Under stress-free conditions, spatial patterns of nitrification potential differed between the two agroforestry systems. Nitrification potential was on average 1.5 times higher in the tree row as compared to the grass-alley in the alley-cropping system, while in the hedgerow system, nitrification potential was on average 40% lower in the grass-alley next to the trees as compared to under the trees and the middle of the grass alley. These results were mostly correlated with the spatial patterns of soil pH. Under flooding stress, resistance was significantly higher under the trees of both systems while a boost of nitrification (27% to 35%) was recorded in the grass-alleys. Resilience did not differ among the distances and the two systems. The ML-SEM approach revealed that nitrification stability was positively related to higher soil organic carbon content and lower soil bulk density in the alley-cropping system. Yet, these relations were not confirmed in the hedgerow systems as none of the tested ML-SEM model fitted to the results obtained in this system.

Our results underlined the impact of the silvopastoral design on the regulation of nitrification. If the adoption of silvopastoral systems can mitigate spikes in N losses from grass alleys right after a flooding stress, results under stress-free conditions revealed higher risks for N losses in the tree rows of the alley-cropping system. Hence, trade-offs between higher risk of N losses under stress-free conditions and their limitation under stressed conditions may exist in these systems, while hedgerows seemed to promote more stable and lower nitrification in both conditions. Through the ML-SEM, our study further encourages the adoption of specific management options (improvement of soil organic matter and bulk density) as sources of external regulation of N losses under extreme climate events.

References:
Greaver, T.L., C.M. Clark, J.E. Compton, D. Vallano, A.F. Talhelm, C.P. Weaver, L.E. Band, et al. 2016. « Key ecological responses to nitrogen are altered by climate change». Nature Climate Change 6: 836‑43. https://doi.org/10.1038/nclimate3088.
Kim, Dong-Gill, Marney E. Isaac. 2022. « Nitrogen Dynamics in Agroforestry Systems. A Review ». Agronomy for Sustainable Development 42 (4): 60. https://doi.org/10.1007/s13593-022-00791-7.
Mettauer, Romane, Lukas Beule, Zita Bednar, Margaux Malige, Olivier Godinot, Edith Le Cadre. 2023. « Influence of Two Agroforestry Systems on the Nitrification Potential in Temperate Pastures in Brittany, France ». Plant and Soil. https://doi.org/10.1007/s11104-023-06309-8.

Speaker: Ms Romane Mettauer (UMR SAS, Institut Agro Rennes-Angers, INRAE)

58_Mettauer.pdf

112 Winter wheat-soy strip intercropping supports natural enemy abundance and pest control in an intensive farming system

Introduction
Intercropping is an increasingly popular management strategy to simultaneously support biodiversity, ecosystem services, and yields in agricultural systems. Nevertheless intercropping studies that look at both yield and ESS, such as pest control, are less common and without them it is difficult to find management that works for both farmers and the environment. The objectives of this study were to test several spatial arrangements of soy and winter wheat, row-relay, wide strip, and patch cropping and understand their yield and pest control potential. We hypothesized that the diversified treatments would support more natural enemies and fewer pests than the sole cropping while maintaining similar yields.

Materials & methods
We used an on-farm study in 2022 and 2023 to test how different forms of spatial diversification of soy and winter wheat can affect pest abundance, pest predation, natural enemies, and yields in Eastern Germany. We specifically studied three types of diversified systems compared to conventional sole cropping - row relay intercropping, wide strip cropping (12x150m), and patch cropping (72.5*72.5m). Crops were managed conventionally with input from the farmer. We monitored pests at wheat flowering, collected ground dwelling carabid beetles and spiders with pitfall traps in May and June, and measured predation rates with aphid predation cards installed in the field 3 times per year. Yield was measured with a combine harvester.

Results
We found that strip cropping generally supported the highest levels of carabid abundance both years and spider abundance in 2022 while producing equivalent, or higher, yields to the sole cropping. Soy and wheat strips had more beetles than their corresponding soy and wheat patches both years and the cropping treatments supported significantly different community compositions. The relay system failed due to insufficient precipitation but supported intermediate levels of natural enemy abundance as well as the highest carabid species richness as measured by the Chao1 index. The results of patches were mixed with yields and abundances either equivalent or lower than the strips and reference treatments. We found no effect of cropping treatment on aphid abundance but overall aphid infestation levels were very low both years and not correlated to natural enemy abundance. As for pest predation, strip cropping had a 51% (2022) and 36% (2023) increase in aphid predation rates compared to wheat patches and 86% and 10% increase compared to the reference wheat.

Discussion
We found that strip intercropping maintained ecological benefits, higher carabid abundance and aphid predation rates, with no yield penalties to the farmers with similar strip yield outcomes found in Canada (Labrie et al., 2016). Strips were likely able to maintain high yields because they are managed identically to their respective sole crop, they act as narrow fields and thus do not require additional driving and can handle pesticides that mixed relay cropping can not. Wide strips may support more natural enemies than patch or sole cropping due to the higher area:border ratio of strips as carabids and spider activity is often higher at edges than field centers (Ávila et al., 2017; Zhao et al., 2013) likely due to increased spatial-temporal resource availability at the edges. While some diversified systems did not perform as well as sole cropping, the strip cropping results show the potential of the system for farmers to diversify their farms in a manner that involves no additional machinery and little additional work.

Speaker: Jennifer Thompson

ESA_72_Thompson_updated.pptx

Physiology & yield

Conveners: Jean-Pierre Cohan, Rafaelle Reumaux

113 Spatiotemporal suitability analysis of sorghum in Germany under climate change

Introducing new crops that can thrive under changing climate conditions is crucial for sustainable agriculture. Sorghum (Sorghum bicolor L.) shows promise as a C4 crop due to its high heat and drought stress tolerance. Its deep root system may contribute to increased soil organic carbon, supporting climate change mitigation. However, one of the challenges in expanding sorghum production in higher latitudes and altitudes, such as Germany, is its low tolerance to chilling stress and the risk of low temperatures, especially during early and late seasons. There is limited information about sorghum production potential in different regions of Germany and its role in climate change mitigation. Achieving optimal crop yield depends on matching available thermal units with the cultivar's requirements. This study aims to develop an algorithm to determine optimal sowing dates, growing season length, and suitable maturity groups for sorghum cultivars and assess the climatic water balance in various regions of Germany.
To reduce this knowledge gap, a spatiotemporal analysis was performed on 13,785 grid cells (5kmx5km) all over Germany. This analysis incorporated a dataset spanning 30 years of historical weather data, as well as projections of climate change based on 12 distinct climate scenarios for the time period between 2031 and 2060. Temperature and rainfall thresholds were employed to create weather indices (WIs) and develop the algorithm. The growing season starts after the last freezing temperature, provided that there is sufficient rainfall (>20 mm) to ensure emergence and the average temperature of five consecutive days is above 15°C. Later, the growing season ends after the first cold temperature happens, provided there is not enough GDD (<20°C) to recover from cold stress and/or complete seed ripening in the next two weeks. Finally, the cumulative thermal units between the start and end dates were calculated using a three-segmented function. This calculation aimed to quantify the duration of the growing season for different maturity groups of cultivars. The cardinal temperatures utilized in the function were obtained by fitting a thermal-time model to the data obtained from an extensive germination test on new cold-tolerant sorghum hybrids tailored for German conditions in constant temperatures ranging from 10 to 40°C with 5°C intervals.
By the middle of the century, better growing conditions are projected to be available for sorghum cultivation, as a longer growing period with more heat can be used for growth and yield formation (Figure 1). This is due to the warming in the main growth phase, particularly in lower altitudes caused by climate change, and at the same time, to the possibility of earlier sowing and later harvesting. While experimental sorghum cultivation has so far been limited primarily to southern Germany, the analyses show that parts of North Rhine-Westphalia and Brandenburg already offer suitable growing conditions. In the future, suitability for cultivation will increase significantly in most regions, and it is expected that varieties with later maturity and correspondingly higher yield potential can also be cultivated with a lower productivity risk.
Further analyses will investigate sorghum's potential cultivation advantage, particularly in regions with an increased risk of drought stress, using phenology models and degree-days as a stress index. Sorghum has demonstrated higher yield stability and levels than maize in trials conducted in dry locations and years with low precipitation, including in 2022 in the Bavarian State Research Center for Agriculture (LfL) field trials in the dry region of Lower Franconia at the Schwarzenau site. These findings highlight sorghum's suitability for cultivation in regions prone to drought stress.
Additionally, the ongoing climate chamber assessment at the Julius Kühn-Institut, Kleinmachnow, aims to quantify the effects of different temperature regimes. This assessment focuses on physiological and morphological development in the early sorghum growth stages. Finally, the research aims to parametrize a process-based crop model through wide north-south gradient field trials and run a comprehensive simulation to provide Germany-wide insights into the yield and stability of sorghum versus maize, identify promising regions for sorghum cultivation in Germany, and understand its complex responses to climate, soil, and water balance.

Figure 1. Germany-wide available thermal units (TU, °C) of the growing season of sorghum under historical (1976-2005 (left)) and future climate conditions (2031-2060, RCP4.5 (center) and RCP8.5 (right)). The growing season is not fixed in different scenarios.

Speaker: Dr Amir Hajjarpoor (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment, Kleinmachnow, Germany)

114 New scales of development for wheat and barley

Introduction
Wheat (Triticum aestivum) and barley (Hordeum vulgare) are cereal grain crops vital for global food security. Adapting crop life cycles and agronomic management to changing climates is critical to increase yields to meet anticipated global demand. The study of crop species development and phenology has thus never been more important or urgent. Such studies depend on the ability to reliably measure and communicate crop development with repeatable and reproducible protocols.

Methods
New scales for assessing the development of wheat and barley were created as part of a national Australian project (Hunt et al., 2020) to improve the accuracy of cereal phenology modelling in APSIM-NG (Holzworth et al., 2018). The scales were developed and tested on a panel of 64 wheat and 32 barley genotypes that were grown in controlled environments with limiting or saturating photoperiod and vernalisation conditions (Bloomfield et al., 2023), and in time-of-sowing field experiments across Australia at sites with diverse geography and climate (Celestina et al., 2023b).

Results
The two new scales of wheat and barley development are the Single Culm Development Scale (SCDS) and the Population of Culms Development Scale (PCDS) (Celestina et al., 2023a). The SCDS defines progression through the lifecycle of an individual plant, whereas the PCDS accommodates population variation in the timing and duration of lifecycle events in a crop canopy (Figure 1).

Figure 1. The Single Culm Development Scale (SCDS) and Population of Culms Development Scale (PCDS) applied to the life cycle of wheat and barley. Adapted from Celestina et al., (2023a).

The SCDS has twelve phases that are disaggregated into stages and is measured on the primary culm of a single plant. Phases in the SCDS may occur concurrently within a single culm. Using the SCDS, a user makes a single observation at one time point to obtain an instantaneous measure of development. For example, a grower or their agronomist might use the SCDS for a rapid assessment of development in the field for the purpose of aligning crop inputs with optimal development stage.

In comparison, the PCDS has ten phases that are delimited by stages and is measured on all culms in a population. Phases in the PCDS are discrete and sequential. Using the PCDS, a user makes multiple observations over time to retrospectively determine the timing of stages and duration of phases. For example, a plant breeder might use the PCDS to compare the time taken for different cultivars to reach 50% anthesis in field evaluation experiments.

Discussion
Compared to existing scales of development such as a the widely-used Zadoks decimal code (Zadoks et al., 1974), the SCDS and PCDS describe development in terms that are unambiguous, objective and quantitative, and they are presented with protocols that ensure repeatable and reproducible results. These new scales distinguish between plant- and crop-level development; they merge and fill gaps within existing published scales; and they are compatible with modern technologies such as simulation modelling and automated image analysis.

The SCDS and PCDS have been successfully used for the parameterisation and validation of the APSIM-NG cereal phenology model and the development of a scheme to classify wheat and barley cultivars based on relative lifecycle length (Celestina et al., 2023b). These applications of the new scales demonstrate their utility and highlights their potential to facilitate ongoing advances in agronomy.

References
Bloomfield, Celestina, Hunt, et al., 2023. Vernalisation and photoperiod responses of diverse wheat genotypes. Crop & Pasture Science 74, 405–422. https://doi.org/10.1071/CP22213
Celestina, Hunt, Brown, et al., 2023a. Scales of development for wheat and barley specific to either single culms or a population of culms. European Journal of Agronomy 147, 126824. https://doi.org/10.1016/j.eja.2023.126824
Celestina, Hunt, Kuchel, et al., 2023b. A cultivar phenology classification scheme for wheat and barley. European Journal of Agronomy 143, 126732. https://doi.org/10.1016/j.eja.2022.126732
Holzworth, Huth, Fainges, et al., 2018. APSIM Next Generation: Overcoming challenges in modernising a farming systems model. Environmental Modelling and Software 103, 43–51. https://doi.org/10.1016/j.envsoft.2018.02.002
Hunt, Celestina, Bloomfield, 2020. Optimal sowing times for wheat and barley cultivars may soon be at our fingertips. GRDC Groundcover Supplement: Enabling Technologies May-June 2020.
Zadoks, Chang, Konzak, 1974. A decimal code for the growth stages of cereals. Weed Research 14, 415–421. https://doi.org/10.1111/j.1365-3180.1974.tb01084.x

Speaker: Corinne Celestina (School of Agriculture, Food and Ecosystem Sciences, University of Melbourne, VIC, AU)

115 Rethinking flowering times of winter cereals for future climates

Introduction
The adaptation of wheat and barley to different growing environments is underpinned by an understanding of crop phenology. The importance of an optimal flowering period (OFP) to ensure the critical period for yield development coincides with favourable seasonal conditions has been demonstrated, whereby the combined risk of frost, heat and drought is minimised, and grain yield potential is maximised (Flohr et al., 2017). Whilst this concept provides useful targets for growers to mitigate risk of abiotic stresses, they remain a major limitation to yields of wheat and barley in Australian rainfed cropping systems (Hochman and Horan, 2018). Future climate predictions increase the complexity of cultivar selection and sowing decisions and present a challenge for breeders, to release new cultivars that combine improved adaptation and stress tolerance, and for growers, to improve farming systems and agronomic practices to capture genetic gains. We consider an integration of genotype (G), environment (E) and management (M) to rethink flowering time in wheat and barley to better enable growers to adapt to climate variability and attain new yield frontiers.

Methods
A comparative analysis was conducted in a series of field experiments across 31 locations in the Australian cropping region from 2010–2022, whereby annual rainfall ranged from 117–978 mm. Grain yield was recorded with respect to flowering time (phenology) to enable us to investigate yield-flowering date relationships in locations where frost, heat and drought are major sources of variation in crop yield, and a significant concern for growers. We applied the field data to test the wheat and barley models in APSIM Next Generation, and conducted long-term simulations of genotype, environment, and management to identify differences in flowering and yield responses.

Results
Grain yield ranged from 0.5–11.8 t/ha, with barley maintaining higher yields than wheat across all yield levels. However, there is evidence to suggest that current genetics is limiting the yield potential of barley in high yielding environments. The OFP for barley was earlier and broader than for wheat, with genotype × sowing time responses observed to be less apparent in barley than for wheat.

Discussion
Our comparative analysis indicates differences in flowering and yield in response to sowing date for wheat and barley. The ability of barley to achieve grain yields greater than wheat at comparative flowering dates suggests wider adaptation of barley in Australian rainfed cropping systems. This may be in part due to the narrow range in phenology responses of current commercial barley cultivars than for wheat, differences in accumulation of biomass and partitioning, or differences in tolerance to frost, drought and/or heat stress. An improved understanding of these species-specific differences will improve future crop model predictions and provide information to growers to refine crop management and reduce the risk associated with sowing time decisions.

References
Flohr, B. M., Hunt, J. R., Kirkegaard, J. A., & Evans, J. R. (2017). Water and temperature stress define the optimal flowering period for wheat in south-eastern Australia. Field Crops Research, 209, 108-119. https://doi.org/https://doi.org/10.1016/j.fcr.2017.04.012

Hochman, Z., & Horan, H. (2018). Causes of wheat yield gaps and opportunities to advance the water-limited yield frontier in Australia. Field Crops Research, 228, 20-30. https://doi.org/https://doi.org/10.1016/j.fcr.2018.08.023

Speaker: Felicity Harris (Charles Sturt University)

116 Yield sensitivity to pre-anthesis heat waves in wheat and barley

1. Introduction
   Climate change is increasing the frequency and duration of heat waves worldwide, decreasing growth and yield of most field crops1. In this scenario, it is crucial to recognise any differences in sensitivity between wheat and barley, crops that are grown alternatively in the same fields. As far as we are aware, there are no field studies comparing wheat and barley responses to heat waves. Therefore, we compared yield sensitivity of these two cereals to pre-flowering heat waves, analysing the responses of grain number per unit area (GN/m2) and its components under field conditions.
2. Materials & methods
   Irrigated and fertilised field experiments were conducted for two years (Exp 1 and Exp 2) at Bell-lloc (NE Spain). Treatments consisted of three well-adapted and high-yielding cultivars of bread wheat (Camargo, Fortunato, Klima) and two-rowed barley (Centella, Meseta, Pewter), exposed to two temperature treatments: unheated (control) and heated plots during 10 effective days in pre-flowering, using portable tents with transparent polyethylene films2.
   At anthesis, we determined the fertile florets number /spikelet. At maturity, we determined yield, biomass, spikes/m2, GN/m2, GN/spike and GN/spikelet.
3. Results
   Heat waves resulted in reductions in yield that were different between cultivars and years (Fig.1). The effect was much stronger in the first than in the second year (Fig.1). Averaging across the cultivars of each species, the reductions in yield were higher in wheat than barley in Exp 1, but mainly because the extreme sensitivity of Klima and the very small sensitivity of Pewter, the other two cultivars of each crop had similar reductions (Fig.1a). Yield reductions were similar between species in Exp 2 (Fig.1b). It must be noted that the actual heat load reached with the portable tents was noticeably higher in Exp. 1 than in Exp 2, and also slightly higher in barley than in wheat. Biomass reductions were in general smaller than yield reductions (i.e.,19% on average across experiments) and similar in both crops and experiments (Fig.1c,d).
   As expected, yield reductions were mainly associated with GN/m2 decreases (Exp 1: R2=0.93, P<0.001; Exp 2: R2=0.79, P<0.001). The reductions in GN/m2 could not be explained by the spikes/m2 (P>0.05) but by GN/spike, being the relationships stronger in Exp 1 than in Exp 2 (R2=0.97, P<0.001 vs R2=0.37, P=0.03). Overall, heat waves slightly decreased the number of fertile florets/spikelet, but substantially decreased the number of grains/spikelet.

4. Discussion
   Heat waves exhibited a clear effect on the reproductive ability, affecting more the reproductive output than the vegetative growth, and increasing grain abortion across the whole spike. GN/m2 reduction seemed to have been related to an increase in the fertile florets lability to set a grain, as heat waves did not affect spike survival (spikes/m2) and the slight decreases in the spikelet fertility (fertile florets number /spikelet). As heat has been shown to negatively impact reproductive organ viability leading to yield losses in field crops, detrimental effects on pollen, ovule viability3,4, and/or ovary size5 might have been responsible for the observed results.
   The higher yield reduction observed in wheat compared to barley could be related to the differences in the flowering timing, which was earlier (10d in Exp 1, 16d Exp 2) in barley than in wheat. Therefore, the background temperatures were higher during the grain filling onset in the latter (average maximum temperature for 10d after anthesis was ~4°C higher in wheat in both experiments), when abortion of grain set could still occur compared to the more phenologically advanced barley.
   Interestingly, the magnitude of yield loss per unit heat load (estimated as yield difference relative to the degrees of increase in the average mean air temperature of each crop-experiment combination) in both experiments was higher for wheat than for barley (on average, 149 vs 79 g/m2 ºC, respectively).The different sensitivity could be in part related to higher yield potential of wheat compared to barley (on average 930 vs 829 g/m2, respectively). Indeed, differences between both species tended to disappear when estimating yield loss per unit heat load as a percentage of control yield, 84 and 90% on average across experiments for wheat and barley, respectively.

5. References

6. J. of ExpBot., 66:3435-3450.
7. FieldCropsRes. 307: 109264
8. Frontiers in PlantSci., 13:918730.
9. NewPhytol.,226:1567-1572.
10. J. of Agric.Sci., 132:453-459.

Speaker: Constanza Soledad Carrera (Universidad de Lleida)

117 Managing soybean within field variability through variable seeding technology

Introduction

We investigated whether varying soybean seeding density and cultivar can tackle within-field variability by conducting a field experiment in Southern Brazil. We tested two hypotheses: that optimal seed density is higher in low yielding environment (HP1) and that high-yielding cultivars perform better than stable ones in high yielding environment and vice-versa (HP2). Three studies have been recently published suggesting that the optimal agronomic seeding rate of soybean is higher in low yielding zones than in high ones: Corassa et al. (2018) for Brazil, and Gaspar et al. (2020) and Carciochi et al. (2019) for North America. These three recent studies on the interaction of zone x sowing density used large datasets coming from various different fields within large ecological regions, however no study — to the best of our knowledge — investigated the effect of the interaction variable rate x zone at within-field level. We further formulated and tested the following three non-mutually-exclusive hypotheses to explain why agronomic optimal seeding rate is higher in low yielding environment: higher seeding rate in low environment increase leaf area index in early stages (HP1.1), plants in low yielding environment have a lower plastic response to density (HP1.2), and lastly that plants in low yielding zones have a lower emergence rate (HP1.3).

Materials and methods

We tested the hypotheses in a two seasons factorial experiment where 3 cultivars x 4 density x 3 environments were tested in 50x50 m plots on a 124 ha field in Southern Brazil, that has been cultivated with precision agricultural techniques over the past 20 years. During the two seasons we measured yield both using a harvest monitor and destructively by analyzing yield components (pods/plant, beans/pod, bean weight), leaf area index using a linear light ceptomer, soil moisture.

Results

Our results support the hypothesis that low yield environment have a higher optimal seeding rate (HP1). Despite the bias in the measurement between destructive and harvester the relation between seeding rate and yield was similar (Figure 1). Based on yield measured using the destructive approach, a seeding rate of 320k seeds/ha instead of 180 produced an increment of 11.4 % (SE. 7.9) in low, a decrement of -3.1 % (SE. 7.1) in medium, and an increment of 1.0 % (SE. 7.3) in high. We further observed that in low environment higher seeding rate induce a stronger initial canopy growth than in medium and high zones (HP1.1). We also observed a stronger correlation between the number of pods in high and medium zones than in low ones, suggesting that the yielding environment where a plant is grown influence its plasticity (HP1.2). We did not find evidence supporting neither HP 1.3 (lower emergence in low yielding environment), nor hypothesis 2 (interaction genotype x zone).

Figure 1: Effect of increased sowing density on yield by zone, measured either destructively. The predicted values are marginalized over year and cultivar, the shaded area is the standard error of the prediction.

Discussion

Our results on low yield zones having a higher agronomic seeding rate (HP1) extends at within-field scale similar observations developed at regional scale by Carciochi et al. (2019; Corassa et al. 2019). The existence of an interaction zone x density both at regional and within-field level induces us to think that in both case low zones are water limited. However at regional scale the major driver of water limitation is the amount of precipitation, and the soil-type , whereas at field scale topography and soil texture — that are often correlated — are a major driving factor. We observed that stable cultivars outperformed the high-yielding cultivar in all zones, the lack of interaction management zone x cultivar could be due to the fact that the 2 experimental years were extremely dry.

References

Carciochi et al. 2019. “Soybean Seed Yield Response to Plant Density by Yield Environment in North America.” Agronomy Journal 111 (July): 1923–32. https://doi.org/10.2134/agronj2018.10.0635.

Corassa et al. 2018. “Optimum Soybean Seeding Rates by Yield Environment in Southern Brazil.” Agronomy Journal 110 (6): 2430–38. https://doi.org/https://doi.org/10.2134/agronj2018.04.0239.

Gaspar et al. 2020. “Defining Optimal Soybean Seeding Rates and Associated Risk Across North America.” Agronomy Journal 112 (May): 2103–14. https://doi.org/10.1002/agj2.20203.

Speaker: Bernardo Maestrini (Wageningen University and Research)

118 Impact of heat and drought stress on yield and subsequent germination of oilseed rape (Brassica napus L.) seeds

Introduction
As climate change accelerates, the frequency and severity of extreme weather events, such as heatwaves and droughts, are on the rise (Rashid et al., 2018; Egli et al., 2005). These challenges significantly impact oilseed rape (OSR; Brassica napus L.), a globally important oil crop, as it faces increased exposure to adverse weather conditions and abiotic stress (Rashid et al., 2018). However, little is known about abiotic stress effects on OSR growth and yield formation as well as the seeds’ subsequent germination ability. Hence, this study aims to explore the impact of heat and drought stress on OSR during different phenological stages.
Material and Methods
We conducted a pot experiment in controlled greenhouse chambers growing single OSR plants cv. Ability in 2L pots filled with local topsoil. We applied four experimental factors to test their single and combined effects, 1.) four levels of heat stress, 24°C, 30°C, 34°C, and 38°C applied for 14 hours with a four-hour adjustment period and 16°C night temperature for all treatments, 2.) two levels of drought stress, i.e., without drought stress (plant available water (PAW) > 60% plant available water capacity (PAWC)) and with drought stress (PAW < 20% PAWC), 3.) two levels of treatment timing, i.e., flowering stage (BBCH 61) and seed filling stage (BBCH 75), and 4.) two levels of treatment duration, 6 days and 12 days. We evaluated the effects separately on the main branch, first and second side branches, and remaining branches.
For the germination test, we placed the harvested seeds of each treatment × branch-level combination on wetted filter paper in 10 cm2 petri dishes in a climate chamber at 22°C. We ran the experiment in three replications, counting germinated seeds 12, 14, 16, 18, 20, 22, and 36 hours after wetting. Using the germination-metrics package in R studio, we computed various germination indices, including the time until 50% and 100% of seeds germinated, median germination time, mean germination rate, and germination speed. We used mixed linear models for further statistical analysis using the lme package in R.
Results and Discussion
The experiments showed significant effects on grain yield, with heat and drought stress, coupled with longer duration, resulting in decreased yields (Fig.1). Stress during flowering had a greater impact on yield compared to the seed filling stage. Interestingly, severe heat stress during flowering, which obstructed fertilization and seed set on the main branch, was fully compensated by additional siliques and seeds on the lower branches, while severe drought stress during flowering could not be compensated. Analysis of seed size and fatty acid composition provided insights into combined heat and drought stress effects. Regarding germination indices, heat, and drought stress together had a pronounced impact compared to individual stressors. Stress during flowering reduced germination percentage and time, especially with both stressors present. Drought stress lowered germination across all branches, while combined stress reduced it in the first two branches only. We explain this by the compensation of destroyed main branch flowers via additional new flowers and seeds on the lower branches after stress ceased. These findings highlight the compensation capacity of OSR against severe heat but not drought stress during flowering supporting the design of more resilient OSR cultivation systems under climate change.
References
Burris, L.G.a.J.S., Effect of heat stress during seed development and maturation on wheat (Triticum durum) seed quality.ll. Mitochondrial respiration and nucleotide pools during early germination. Canadian Journal of Plant Science, 1995. 75(4): p. 831-839
Egli, D.B., et al., Air Temperature During Seed Filling and Soybean Seed Germination and Vigor. Crop Science, 2005. 45(4): p. 1329-1335
Gillen, A.M., et al., Effects of Maturity and Phomopsis longicolla on Germination and Vigor of Soybean Seed of Near-Isogenic Lines. Crop Science, 2012. 52(6): p. 2757-2766
Rashid, M., et al., Heat stress during seed development affects forage brassica (Brassica napus L.) seed quality. Journal of Agronomy and Crop Science, 2018. 204(2): p. 147-154
Toledo, M.Z., et al., Physiological quality and enzymatic activity of crambe seeds after the accelerated aging test. Acta Scientiarum. Agronomy, 2011. 33(4)

Speaker: Ms Dima Sabboura (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment, Kleinmachnow, Germany)

7:15 PM Cocktail

8:15 PM Social dinner

Thursday, August 29

EFELE/ValEnSol + The walled city of Saint-Malo

Convener: Olivier Godinot

Vegetable production area + Mont Saint-Michel

Conveners: Vincent Faloya, Antonin Pépin

UE La Motte + Brocéliande forest, the birthplace of legends

Conveners: Blandine Lemercier, Matthieu Carof

Zone Atelier Armorique + La Gacilly photography festival

Conveners: Cendrine Mony, Sébastien Boinot, Véronique Lucas

Side-event: Root2Res mid-term symposium

Leisure time + Tour of the city of Rennes: Pick up of the lunch bags

Convener: Edith Le Cadre

Leisure time + Tour of the city of Rennes: Guided tour

Convener: Edith Le Cadre

Friday, August 30

Agro-ecological transitions at the landscape and territorial levels (assessments): carbon cycle

Conveners: Elisa Marraccini, Juan Nieto Cantero

119 Challenges and opportunities for increasing organic carbon in vineyard soils: perspectives of extension specialists

Context description and research question: An increasing number of farmers are considering the impact of conservation practices on soil health to guide sustainable management of vineyards. Understanding impacts of soil management on soil organic carbon (SOC) is one lever for adoption of agroecological practice with potential to help maintain or improve soil health while building SOC stocks to mitigate climate change (Amelung et al., 2020). Despite the potential of perennial cropping systems as C sinks, a major part of the world’s agricultural landscapes remains dominated by specialized practices and, although winegrowers understand how to improve SOC, they face real or perceived challenges in adopting soil conservation practices. In this study, we analyzed extension specialists’ perceptions of the challenges and opportunities to maintain or increase SOC in vineyard soils in two main wine producers, in France and in the United States. Our goal was to characterize current practices and better understand the challenges at the farm level (structural barriers, trade-offs, conflicts of interest, education and training) regulating adoption of practices favorable to SOC. The 4 contexts are USA-cool, USA-warm, F-cool and F-warm vineyards.
Method and theoretical background: To identify universal principles in vineyard soil management, we conducted exploratory semi-structured interviews in both warm and cool climate areas in France and in United States, to get some universal practices and challenges, not depending on climate variation. The results could then, be transposed to any other vineyard. We identified 16 extension specialists in each country; eight in cool climates and eight in warm climates. Our hypothesis was that the structure of the supply chain in each of the four regions (France/warm, France/cool, U.S./warm, U.S./cool) would impact barriers and levers for adoption.
Results and discussion: We found seven SOC-favorable practices already managed in France and USA, both in cool and warm climates. All extension specialists reported that cover crop, organic fertilization, tillage reduction, grazing, agroforestry, mulching and herbicide use reduction are already implemented by some winegrowers and should be further incentivized. We found details about cover crop characteristics including the surface area of cover crop, the diversification of spontaneous and sown the species in cover crop, and turning over the cover crop. Using compost or returning pruning residues to the soil were highlighted by interviewees as important practices for organic fertilization. We found economic, agronomic, educational, conflict of interest and structural challenges to practice adoption. 69% of the extension specialists mentioned the cost of the practice as the first challenge to adoption SOC-favorable practice, and the potential negative impacts of yield. An agronomic challenge identified specifically was concerns over competition of cover crop with vine vigor. Education and training of winegrowers needed included knowledge to implement the practices at the field scale and systems redesign at the farm scale. Conflicts of interest included potential food safety issues associated with livestock grazing, particularly in table grape production. A first structural barrier identified included climate of the location of the vineyard for competition for water and nitrogen, which is a big issue with the actual change of the climate. A second structural barrier identified included planting density for agroforestry in Protected Designation vineyards and availability of organic fertilizers next to the farm. Greater emphasis on addressing the challenges to adoption of SOC-favorable practices is urgently needed to inform national and regional agricultural policies in both countries.

Speaker: Marie Thiollet-Scholtus (INRAE)

97_Thiollet_Scholtus.pptx

120 The carbon footprint of narrow-leaved lupin (Lupinus angustifolius) in Germany

Introduction
Reducing greenhouse gas (GHG) emissions from agriculture is crucial in combating climate change, as this sector contributes significantly to overall anthropogenic GHG emissions. In crop production major emissions, stem from the production of Nitrogen (N) fertilizer and related nitrous oxide (N2O) emissions in the field. The broader integration of legumes in crop rotations can potentially support climate change mitigation, as they can fix atmospheric nitrogen through symbiotic relationships with soil bacteria and reduce the reliance on synthetic fertilizers and respectivelyespectiveGHG emissions (van de Noort, 2016). Narrow-leaved lupin (Lupinus angustifolius), a legume well-suited well suited to temperate climates with specific nutritional qualities, has the potential to reduce carbon footprints associated with agriculture and human nutrition (van de Noort, 2016). By processing it into protein-rich plant-based milk and meat substitutes, lupin could significantly contribute to reducing the carbon footprint of the German food sector. In this study, weand hence aim to investigate lupin carbon footprints for various locations and over several years in Germany, to understand how lupin growth patterns relate to GHG emissions and to explore its potential for mitigating climate change in key German growing regions.
Material and Methods
In this study, we analyzed GHG emissions from various lupin genotypes across 14 sites in Germany's main growing regions from 2002 to 2015. Data were sourced from post-registration variety trials published in annual reports by state-level authorities (e.g., Jentsch et al., 2017; Zenk et al., 2017). The dataset includes genotype-, location-, and year-specific yield information (grain yield, thousand kernel mass, grain protein content) and management data (timing, type, and amounts of sowing, fertilization, plant protection measures).
GHG emissions associated with lupin cultivation were quantified using a life cycle assessment (LCA) approach, considering all cultivation stages from land preparation to harvesting. The system boundary was defined from cradle to farm-gate, specifically focusing on GHG emissions. Emissions stemming from material and energetic inputs (e.g., diesel for field operations) were estimated using emission factors from established databases, while N2O emissions were assessed using the IPCC Tier 2 approach. Lupin cultivation for all genotypes, locations, and years was assumed to occur on a 500-hectare farm with an average plot size of 20 hectares and an average farm-to-field distance of four kilometers. Data management and LCA calculations were performed using R Studio to comprehensively quantify GHG emissions. Functional units considered were GHG emissions per unit land (carbon footprint land; CFPL), per unit grain (carbon footprint grain; CFPG), and per unit protein (carbon footprint protein; CFPP). Statistical tests, specifically ANOVA, were utilized to assess significant differences in CFPL, CFPG, and CFPP among genotypes, locations, and years
Results and Discussion
Across numerous combinations of lupin genotypes, locations, and years, the carbon footprint per unit land, grain, and protein was assessed. Notably, N2O emissions were identified as the leading contributor to total greenhouse gas emissions in lupin cultivation, followed by emissions from diesel use, seed sowing, and fertilizer application. GHG emissions stemming from plant protection products comparatively low due to small dosages applied per hectare. Significant differences were observed among genotypes, locations, and years for all functional units investigated (Fig. 1). While there is limited potential to further reduce N2O emissions concerning the carbon footprint per unit land Fig(1), advancements in breeding and management practices could enhance the carbon footprint per unit grain and protein. To comprehensively evaluate the climate change mitigation potential of lupin and other legumes, conducting a life cycle assessment at the crop rotation level is planned, considering lupin's role in substituting mineral nitrogen for the subsequent crop. Additionally, employing agroecosystems models and adopting a model-based Tier 3 approach for estimating N2O emissions will enhance the analysis. Plans also include broadening the assessment to encompass the entire value chain, considering production, transport and processing to different food items, to thoroughly assess the climate change mitigation potential of regionally produced lupin-based proteins.

References
Jentsch, U., Günther, K., Guddat, C. (2017) Landessortenversuche in Thüringen, Blaue Lupin, Versuchsbericht 2016. Thüringer Landesanstalt für Landwirtschaft, Jena; Themenblatt-Nr.: 23.02
Van de Noort, M. (2016) Lupin: An Important Protein and Nutrient Source, Sustainable Protein Sources. Elsevier https://doi.org/10.1016/B978-0-12-802778-3.00010-x
Zenk, A., Pietz, G., Michel, V. (2017) Sommergetreide und Leguminosen 2017, Ergebnisse Landessortenversuche - Anbaugebiet „D-Nord/ MV Süd“. Landesforschungsan

Speaker: Ms Dima Sabboura (Julius Kühn Institute – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment, Kleinmachnow, Germany)

121 The agronomic potential for soil carbon sequestration by cover crops in three European countries

Introduction
Cultivating cover crops is considered one of the most promising practices for agricultural soil carbon sequestration (Kaye and Quemada 2017). However, biophysical estimates of the potential for offsetting greenhouse gas emissions (GHG) by cover crops have been critiqued as unrealistic (Moinet et al., 2023). This is due to the omission of agronomic and socioeconomic constraints, such as the length of the growing season. Understanding and incorporating farmers’ views on the feasibility of soil carbon sequestration practices is an indispensable step before implementing any schemes for carbon sequestration in agricultural land.
We developed and tested a methodological framework to quantify the potential adoption of cover crops in three European countries (the Netherlands, Germany and Spain). Using this framework, we answered the following research questions: (1) What is the current adoption of cover crop cultivation? (2) What is the potential and adoption gap for the cultivation of cover crops? (3) Which agronomic constraints hinder further implementation?

Materials and Methods
Qualitative interviews were conducted with agricultural experts in each region (n = 8) to gain a deeper understanding of the farming systems and used to formulate a context-specific questionnaire distributed online at the three study sites.
We developed a framework that allowed the quantification of adoption gaps, identifying constraints that lie beyond the farmer’s immediate control or those that can be optimised through best management. Data was collected through an online survey among 321 farmers in three European countries (Germany, the Netherlands and Spain). Farmers were asked to report their crop rotation, cover crop cultivation and area of crops sown in spring. Based on these data, we quantified the potential agronomic adoption and relative adoption gap. Afterwards, farmers were asked to evaluate drivers and constraints linked to their adoption gap. Comparing adoption rates across different edaphic and environmental settings provided a context-specific overview of opportunities for increased adoption (figure).

Results
First results show that the current adoption of cover crops varies greatly depending on climate: While almost all farmers employed cover crops in the Netherlands, around 80% of the farmers did so in Germany and only 10% in Spain.
In Germany and the Netherlands, current adoption rates are close to the attainable potential, with further expansion limited due to existing winter cover in the crop rotation. On average, the adoption gaps were around 25% and 20% of the agricultural area in the Netherlands and Germany, respectively, when considering the share of land with a spring-sown crop. In Spain, adoption is constricted by water availability. Only a few farmers adopt cover crops in irrigated arable land.
Agronomic constraints generally impede the further expansion of cover crops. In the Netherlands and Germany, the most cited constraints were related to cover crop establishment, especially after a late harvest of a previous crop.

Discussion
Our findings show that, based on growing seasons, there is only a small gap for cover crop expansion in Germany and the Netherlands. Moreover, the continuous implementation of cover crops faces challenges from weather constraints, particularly following late harvests and, in Spain's case, water availability, which make the successful establishment of a cover crop in all fields and all seasons challenging.
Given the narrow-identified gaps and the fact that most of those gaps can be explained by agronomic constraints outside management optimisation, continuous adherence to the practice might not be feasible. Based on these insights, there is a limited agronomic potential for additional C sequestration by cover crops in Europe.
Despite multiple policies and regulations encouraging adoption, based on the agronomic constraints presented here, we estimate that some of the forecasted biophysical potentials of C sequestration are overestimated by at least 70% for our study sites, without considering other limiting factors, such as saturation or leakage effects.

References
Kaye, J.P., Quemada, M. Using cover crops to mitigate and adapt to climate change. A review. Agron. Sustain. Dev. 37, 4 (2017). https://doi.org/10.1007/s13593-016-0410-x
Moinet, G. Y., Amundson, R., Galdos, M. V., Grace, P. R., Haefele, S. M., Hijbeek, R., Van Groenigen, J.W.,, Van Groenigen, K.J., David S. & Powlson, D. S. (2023). Climate change mitigation through soil carbon sequestration in working lands: A reality check. Global Change Biology, 30(1), e17010.

Speaker: Marti Vidal Morant (Wageningen University)

342_VidalMorant (1).pptx

122 Multi-actor strategy to screen lentil landraces for organic agriculture in Lyon metropolitan area

1. Introduction
   Providing solutions to facilitate agro-ecological, dietary and energetic transitions is a way to limit consequences of the climate change. Due to their ability to fix nitrogen in the soil and their nutritional qualities, pulses are crops that can contribute to these transitions. However, the poor varietal offer in pulses is an obstacle to increase their cultivation, especially for lentils (Lens culinaris Medik.). The main lentil cultivar is Anicia: obtained in 1966, it represents up to 80% of the French lentil production (Terre Univia, 2022). Participatory variety selection may lead to an improvement of varietal offer for underutilized crops (Chable et al., 2014; FAO, 2011).
   Lyon is one of the cities with the highest increase of temperatures in the South of France: hence, between 1980 and 2009, the climate changes from temperate humid to submediterranean (Lelièvre et al., 2011). In the metropolitan area, various actors including the Metropolis of Lyon, carry a strong political will to screen lentil varieties in order to enlarge the varietal offer and be able to provide nutritious organic pulses to collective restaurants.
   The aim of this study is to conduct a multi-criteria evaluation of numerous lentil varieties to select those best suited to the many challenges facing the Metropolis of Lyon.

2. Materials, methods
   This project involves several types of actors: researchers, CRBA (Centre de Ressources de Botanique Appliquée, an associative seed bank), Metropolis of Lyon, the Pauline & Valérie Mercan Foundation, farmers, catering professionals and healthcare professionals.
   The first step of the project is to collect varieties from seed banks (IPK genebank, GEVES, INRAE, ProSpecieRara, CRBA). The received samples were cultivated in order to multiply and screen the varieties. Participatory meetings have been organized to identify agronomical and nutritional traits of interest. The chosen agronomical traits were characterized according to established protocols (Ahmad et al., 2021; UPOV, 2015). In the second year of the project, a mother-baby trial has been set up in several on-farm experimental sites according to the methodology developed by Snapp (2002) to select lentils adapted to the various microclimates corresponding to the farms located in the experimental area.

3. Results
   110 lentil samples were collected from seed banks and evaluated according to their seed phenotype and distance from their origin center of cultivation. Among them, 35 varieties, representative of the observed diversity, were sown and evaluate in field in 2023, leading to the identification of five different clusters (PCA analysis). The most discriminating traits were the color of the grain, the time of flowering and the yield.
   Finally, 14 varieties have been collected in sufficient quantity to integrate a mother-baby trial in 2024 (figure 1). In addition, five control varieties provided in large quantity by partner farmers and ProSpecieRara have been sown in the five on-farm experimental sites.

4. Discussion
   The initial varieties have been pre-selected, particularly from an agronomic point of view, thanks to this first original screening. They are now going to be assessed for morphologic and agronomic traits but also for nutritional traits (analyses of proteins, fibers, minerals, trace elements) which will help to identify varieties and maybe ideotypes corresponding to the criteria of the project’s stakeholders. Moreover, the developed methodology will be applied to other pulse crops (peas and beans).

5. References
   Ahmad, N. S., Moradi, N., Rafaat, J. G., & Mohammed, D. J. (2021). Genetic Variability and Heritability Estimates of Agronomic Traits in Lentil (Lens culinaris Medik.). Romanian Agricultural Research, 38, 9‑20. https://doi.org/10.59665/rar3802
   Chable, V., Dawson, J., Riccardo, B., & Goldringer, I. (2014). Seeds for Organic Agriculture : Development of Participatory Plant Breeding and Farmers’ Networks in France. Organic Farming, Prototype for Sustainable Agriculture, 383‑400. https://doi.org/10.1007/978-94-007-7927-3_21
   FAO (2011). Deuxième plan d’action mondial pour les ressources phytogénétiques pour l’alimentation et l’agriculture.
   https://doi.org/10.17180/MEZ5-YV03
   Lelièvre, F., Sala, S., Ruget, F., & Volaire, F. (2011). Evolution climatique du Sud de la France 1950-2009, Projet CLIMFOUREL PSDR-3. Série Les Focus PSDR3.
   Snapp, S. (2002). Quantifying Farmer Evaluation of Technologies : The Mother and Baby Trial Design.
   UPOV (2015). Lentille—Principes directeurs pour la conduite de l’examen de la distinction, de l’homogénéité et de la stabilité.

Speaker: Lucile Sainmont

123 Increasing circularity – Impacts of co-product management on soil carbon and greenhouse gas emissions

Introduction
In Europe and the UK, farms have typically become highly specialised with little or no integration between crops and livestock enterprises either between or within farms, resulting in an agricultural system that is highly dependent on purchased inputs for the supply of nutrients to both crops and livestock. The consequence of this specialisation has meant there is a risk of soil fertility declining in arable areas. In contrast, in livestock dominated areas, there has been an excessive build-up of nutrients in the soil, increasing the risk of pollution (Watson et al., 2019). Pollution of the environment coupled with greenhouse gas emissions from agriculture has resulted in increasing interest in the concept of the nutrient circularity. Frequently overlooked in assessing nutrient circularity in agricultural systems, is the return of nutrients to the soils which are critical for maintaining soil health and rebuilding natural capital. Co-products, such as crop residues, provide materials that can be manipulated and used in different ways to enhance soil fertility. Here, the effect of co-product use on-farm has been assessed through a rapid evidence assessment (REA). The review focused on assessing the effect of co-product management on soil nutrient status, carbon stocks and nutrient losses.
Methodology
The focus of the REA was to assess the effect of the co-product management on soil nutrients, carbon stocks and nitrous oxide emissions. The REA conducted in SCOPUS on 26/2/2023 was restricted to systematic reviews and meta-analysis, and articles published in English. The co-product management options included in the search term were catch crop, grazed and ungrazed cover crops, waste, manure, residues, composts, digestates and straw. Initially 236 papers were identified of which 20 contained data directly relevant to European climates. Papers that reported the results at a global scale were excluded from the analysis. The data extracted was the effect of the application of the co-product on soil nutrients, carbon stocks or nutrient loss relative to the same management without the addition of the co-product.
Results
The results indicate that there are few meta-analyses or systematic reviews that report the effect of the use of co-products on soil nutrients and nutrient loss from agricultural systems. Composts and treated manures were only reported in one paper each. The co-products of cover crop residues and manure, crop residues were reported in twelve, seven and four papers, respectively. These papers mainly focused on soil carbon and nitrous oxide emissions. Except for crop residues and soil carbon, the number of observations included in each of the mean data points ranges from 362 for nitrous oxide emissions from manure to 966 for nitrous oxide emissions from cover crops. The effect of including cover crops was to increase nitrous oxide emissions by a factor of 2.25 (range 0.64-5.95), more than doubling the initial emissions. This compares with a factor of 1.8 (0.6-3.63) and 1.49 (0.98-2.16) for manures and crop residues, respectively. The comparable values for soil carbon were 1.08 (1.04-1.13), 1.11 (1.05-1.29), 1.14 (1.03-1.24) for cover crops, manures and crop residues respectively.
Discussion
The REA highlighted that there is currently a lack of meta-analyses or systematic reviews that assess the effect of co-product use that is specifically relevant to European agriculture. Although the results from the global meta-analysis may be relevant, it is important to recognise that crops, and pedoclimatic conditions may influence the magnitude of these effects. The results highlight that use of cover crops, manures and crop residues are likely to increase both soil carbon storage and nitrous oxide emissions. Increasing soil carbon is likely to improve the soil structure and improve fertility. However, from a net zero perspective, this needs to be traded off against the increase in nitrous oxide emissions. It is also important to recognise that the papers assessed have focused on soil carbon storage, which may not result in long-term carbon sequestration. This work also highlights the importance of assessing all the flows within the farming systems and identifying opportunities within the entire system to mitigate emissions. The social and economic implications of co-product utilisation also need to be considered.
References
Watson, C. A. et al. (2019). Linking Arable Cropping and Livestock Production for Efficient Recycling of N and P. Agroecosystem Diversity: Reconciling Contemporary Agriculture and Environmental Quality, 169–188.

Speaker: Kairsty Topp (SRUC)

236_Topp.pptx

Climate change adaptation and mitigation

Conveners: Marlene Palka, Audrey Alignier

124 Simulating interactions between farms: adaptive network of biomass flow and individual behaviors

Introduction

Crop-livestock systems at landscape level consist of interactions between farms (often specialized) promoting ecological interactions over space and time between crops, pastures and livestock sub-systems. They can increase resources circularity to satisfy short-term (e.g. farm autonomy) and long-term goals (e.g. resilience to climatic hazards and agricultural practices change) (Martin et al. 2016).

Little research is available on the impact of farms involvement in exchanges of products with other farms (constituting a farm network) on autonomy and resilience, both at farm and network levels.

Agent-based models (ABM) represent individual agents (farms) making decisions and acting independently from each other while considering social behaviors such as social interactions (Huber et al. 2018). We aimed to assess, via an ABM, the autonomy and resilience of a farm network in a given region in response to different scenarios.

Material & Methods

We built an ABM in which agents are farms (cereal, crop-livestock, and livestock) and the cooperative. At each time step (year), on-farm products (grains, forage, straw, manure) can be traded if needed or in surplus with other farms, the cooperative or the global market. Decisions to trade with another farm are based on a score that takes into account i) the distance to cover, ii) the quantity of biomass that can be exchanged, iii) trust between farmers, representing farm trade habits and evolving according to past trade experiences, iv) individual strategy (preference for exchanged quantity or social connection).

The ABM was implemented on the GAMA platform for the Ariège region (France), then explored with the openmole platform (Reuillon et al. 2013). Explorations showed that 300 farms could be representative of the functioning of the region and that stability is reached after 8 steps. This stable state is our baseline scenario from which we will include perturbation to simulate scenarios.

Main outputs indicators for each farm are: i) local farm autonomy: in nitrogen, ratio of quantity of consumed products coming from the farm or other farms over total quantity of consumed products, ii) betweenness centrality: degree of inclusion of a farm in the network.

Results

For the baseline scenario, network autonomy is low (0.24), with farm autonomy much higher for crop-livestock farms (0.773), than livestock (0.279) and crop farmers (0.007) (See Attachement). This variability is also observed between livestock types: the local autonomy is higher in ovine crop-livestock farms (0.98) than in bovine ones (0.61) and ovine livestock farms have lower local autonomy (0.22) than bovine ones (0.31).

On average, crop-livestock farms have more connections than livestock and crop farms (respectively 3.04, 1.95 and 1.21), and show higher levels of betweenness centrality (respectively 0.019, 0.009 and 0.004).

Mean distance between trading farms is the lowest for protein grain, and differs whether the buyer is a livestock or crop-livestock farm (61km and 27km respectively). Highest mean distances are reached for manure and cereal straw (54km both).

Discussion and conclusion

Our modeling approach combines both technical and social aspects of farm interactions. Based on the baseline scenario results, we showed that crop-livestock farmers are better included inside the farm network, mainly as they can be supplier and requestors. We highlighted that manure is scarce in the region. Crop farmers are bound to a low autonomy in simulations as their only local need is for fertilizers (thus for manure).

We are simulating scenarios of perturbations to compare with the baseline: i) changes in resource availability, to simulate yield variability, ii) farm number, farm structure (crop area, number of livestock heads), iii) new practices (cover crop grazing). New practices may help increase farms’ autonomy, while decrease in farm number and increase in farm areas may increase attraction to the local cooperative (versus other farms) and/or lead to a concentration of connections between farms. These results could be presented at the conference. They will provide insights on performances and resilience of crop-livestock systems at landscape level facing perturbations.

References

Huber R, et al. (2018) Representation of decision-making in European agricultural agent-based models. Agricultural Systems 167:143–160. https://doi.org/10.1016/j.agsy.2018.09.007

Martin G, et al. (2016) Crop–livestock integration beyond the farm level: a review. Agron Sustain Dev 36:53. https://doi.org/10.1007/s13593-016-0390-x

Reuillon R, et al. (2013) OpenMOLE, a workflow engine specifically tailored for the distributed exploration of simulation models. Future Generation Computer Systems 29:1981–1990. https://doi.org/10.1016/j.future.2013.05.003

Speaker: Mr Aurélien Peter (AGIR, Univ Toulouse, INRAE, 31326 Castanet-Tolosan, France)

125 Using soil-crop models to investigate the impacts of contrasted livestock integration into cropping systems with climate change

Food systems are at the core of numerous negative impacts, involving e.g. greenhouse gas emissions, biodiversity or human health. To address part of these problems, there were multiple calls to reduce or even suppress animal products in human diets (Tilman and Clark, 2014). However there is still no consensus regarding the extent of reduction of these animal source foods to mitigate the environmental impacts of food systems (Frehner et al., 2020). In addition, climate change poses an enormous threat on crops and livestock, while at the same time, agricultural systems constitute key levers to mitigate climate change. In this context, process-based models are essential to investigate the potential outcomes of prospective scenarios such as keeping highly specialized agricultural systems or suppressing livestock. Such studies are still very rare, most of comparisons in agricultural circularity using mass-flow models which do not allow to investigate climate change scenarios and perform granular analyses of carbon and nitrogen cycles.

In this work, we wanted to study the impacts of contrasting livestock integration on cropping systems sustainability (productivity, soil organic carbon, resistance to extreme climatic events). In that objective, we compared three different 8-year crop rotations contrasting by their level of livestock integration and by the commodities they supply for human diets. Each was simulated with the soil-crop model STICS (Brisson et al., 2009) over a 24-year period of time in Belgian pedoclimatic conditions, in five different climate scenarios: 1980-2010, 2040-2070 (RCP4.5 and RCP8.5), and 2070-2100 (RCP4.5 and RCP8.5). The first one is Business-as-usual with common cash crops of Belgium and in which manure is imported from other livestock farms in exchange of exported straw. The second system is called Vegan, and simulates an agriculture where livestock would be banned. It therefore does not use manure, but all crop residues are incorporated into the soil after harvest. The third system is qualified as Integrated crop-livestock (ICLS). It uses sheep as functional tools to manage weeds and pests through grazing of temporary pastures, which last 2.5 years over the 8-year rotation.

Simulated yield evolutions with climate change varied between crops, ranging from losses (up to -49%) to gains (up to 51%). It appeared that global yield shifts due e.g. to CO2 fertilization effect and higher crop stresses are modulated by the impacts and occurrence of extreme climatic events. The resistance to these extreme climatic conditions is influenced by the contrasting livestock integrations, even when comparing similar crops that are common to the different circularity scenarios. For example, the loss of soil organic carbon in the Vegan system provokes greater stomatic water stresses and lower crop resistance. In the contrary, closely connecting crops with livestock through the integration of temporary grazed grasslands into the rotation increases soil organic carbon, and hence improves soil capacity to retain water.

Finally, this study aims at illustrating how soil-crop models might be coupled with external methodologies to explore the outcomes of potential agricultural circularity scenarios for food systems under historical and future climatic conditions. We believe that extending such comparisons to various agro-pedoclimatic conditions would allow to better understand the impacts of food policies on the climate change adaptation and mitigation capacities of agricultural systems.

References:
Brisson, N., Launay, M., Mary, B., Beaudoin, N. (2009). Conceptual basis, formalizations and parameterization of the STICS crop model. Ed. Quae. 297
Frehner, A., Muller, A., Schader, C., De Boer, I. J. M., & Van Zanten, H. H. (2020). Methodological choices drive differences in environmentally-friendly dietary solutions. Global Food Security, 24, 100333.
Tilman, D., & Clark, M. (2014). Global diets link environmental sustainability and human health. Nature, 515(7528), 518-522.

Speaker: Mathieu Delandmeter (University of Liège)

126 Calibrating CERES-Barley for ideotyping climate-smart spring barley under German growing environments

1. Introduction
Although breeding progress is contributing to climate change mitigation through increased land use efficiency (Laidig et al., 2021), nitrogen use efficiency (Laidig et al., 2024), and a decreased carbon footprint (Riedesel et al., 2022), increasingly adverse weather conditions exert negative impacts on crop production and food security. Crop modeling serves as a powerful tool to investigate the interactions between genotype (G), environment (E), and management (M) by simulating the plant-soil-atmosphere system. Through in-silico experiments, crop models enable the simulation of crop growth, development, and yield formation under future climatic conditions. This study aims to define ideotypes, i.e., in-silico genotypes that exhibit high mean yields at high yield stability, and a minimized carbon footprint under different environments using the crop model CERES-Barley model embedded in DSSAT. By calibrating and evaluating the model based on field experiments and multi-environment trials, we aim to generate robust predictions and design a climate-smart in-silico genotype.

2. Material and Methods
To effectively employ crop simulation models, calibration for target genotypes and environments is essential, followed by performance evaluation to ensure accurate predictions. In this study, we use detailed multi-environment phenology, growth, and yield data of the elite barley cv. RGT Planet to parameterize the CERES-Barley model, based on an extensive two-year field experiment in Berlin Dahlem, where we collected growth and yield data under three irrigation treatments and a large dataset consisting of a multi-environment trial dataset covering 33 site years of pre-registration trials from 2014 to 2019. We use the time series estimator tool (TSE) for DSSAT to calibrate cultivar-specific coefficients by minimizing the normalized root mean square error (nRMSE) between simulated and observed data. We then use the parametrized and evaluated CERES-Barley model to investigate yield production under current and future climatic conditions. Through a hybrid method that combines the CERES-Barley crop model and life cycle assessment, we conduct in-silico experiments by simulating weather conditions based on the 17 RCP-climate scenarios of the DWD core ensemble (DWD, 2018) from 2006 to 2099. Subsequently, we cluster the yearly data into distinct groups according to environmental conditions (drought intensity, drought timing, extreme weather events, etc.) and their corresponding environmental impacts (i.e., carbon footprint). Using these weather clusters, we conduct sensitivity analysis to define various sets of model cultivar parameters, representing ideotypes with different combinations of genotypic traits aimed at achieving objectives such as high yields, yield stability, or low carbon footprint under various environmental conditions and management practices.

3. Results and discussion
The calibrated and evaluated CERES-Barley model provided robust simulation results for the elite cv. RGT Planet. The simulated yields show an increase in mid-century, under the RCP 4.5 and RCP 8.5, with a lower slope at the end of the century. The ideotyping exercise revealed significant variations in cultivar coefficients and corresponding crop traits across various environmental scenarios and management practices. This assessment facilitated the identification of ideotypes tailored for a maximized yield, yield stability, and a reduced carbon footprint. The results highlight the significance of integrating genotype × environment × management interactions in designing climate-smart ideotypes geared towards climate change mitigation while maximizing agricultural productivity.

4. References
Laidig, F., Feike, · T, Klocke, · B, Macholdt, · J, Miedaner, · T, Rentel, · D, & Piepho, · H P. (2021). Long-term breeding progress of yield, yield-related, and disease resistance traits in five cereal crops of German variety trials. Theoretical and Applied Genetics, 134, 3805–3827. https://doi.org/10.1007/s00122-021-03929-5
Laidig, F., Feike, T., Lichthardt, C., Schierholt, A., & Piepho, H. P. (2024). Breeding progress of nitrogen use efficiency of cereal crops, winter oilseed rape and peas in long-term variety trials. Theoretical and Applied Genetics, 137(2). https://doi.org/10.1007/S00122-023-04521-9
Riedesel, L., Laidig, F., Hadasch, S., Rentel, D., Hackauf, B., Piepho, H. P., & Feike, T. (2022). Breeding progress reduces carbon footprints of wheat and rye. Journal of Cleaner Production, 377, 134326. https://doi.org/10.1016/J.JCLEPRO.2022.134326

Speaker: Asmae Meziane (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment)

127 Rye in a changing climate: insights from crop modelling in key northern hemisphere regions utilizing DSSAT-CSM-CERES-Rye

Introduction

Process-based crop models are helpful tools in studying genotype × environment × management (G × E × M) interactions in agriculture (Boote et al., 2013). With climate change (CC) threatening global food security through increased droughts, higher temperatures, and altered precipitation patterns, understanding its potential effects on crop production is crucial (Challinor et al., 2014). Crop modeling is pivotal for exploring adaptation measures to CC challenges (Asseng et al., 2015). This study focuses on rye, a promising crop in temperate regions due to its high resource use efficiency, adaptability to drought and frost conditions, and low input requirements. Assessing rye production under current and future climatic conditions is essential for adapting cereal production in key northern hemisphere regions. Our research aims to provide insights into the potential impact of CC on rye production, utilizing the adapted DSSAT-CSM-CERES-Rye model to evaluate its effects on crop yields and identify adaptation strategies (Shawon et al., 2022). Additionally, this study enhances understanding of rye's resilience and adaptability under changing climatic conditions, supporting the development of sustainable agricultural practices amidst CC challenges.

Materials and Methods

In this study, the LARS-WG6 stochastic downscaling model (Semenov et al., 2002) was used to generate future climate data, calibrated and validated with historical climate data from 1985 to 2020 across multiple locations: Bohnhausen (Germany), Jogeva (Estonia), Jokioinen (Finland), Raasdorf (Austria), Choryn (Poland), and Lethbridge (Canada). Daily climate variables were simulated at these locations by leveraging the statistical characteristics of observed climate data, with interpolation for ungauged locations conducted using the inverse distance weighting method. Weather generator parameters from two global climate models (GISS-E2-R-CC and HadGEM2-ES) were applied under the RCP 4.5 and RCP 8.5 scenarios. The impact of climate change on rye production was evaluated using the CSM-CERES-Rye model, which simulated critical crop characteristics, including phenology, growth, and yield. Simulations covered three time periods: the base period (2001-2020), mid-century (2031-2050), and end-century (2081-2100), providing a comprehensive assessment of rye production under various climate change scenarios throughout the 21st century.

Results and discussion

The study evaluated projected changes in crop yields under different representative concentration pathways (RCPs) for selected sites (Figure 1). Results revealed that by mid-century, RCP4.5 was anticipated to yield an increase ranging from 8% to 48%, while RCP8.5 exhibited a larger increase ranging from 38% to 87%. Similarly, by end-century, RCP4.5 was projected to yield an increase ranging from 14% to 60%, while RCP8.5 was expected to yield an increase ranging from 43% to 93%, taking into account CO2 fertilization. Further analysis of location-specific data may unveil interesting disparities in projected yield changes. Additionally, it's noteworthy that future rye production in the northern hemisphere could potentially benefit from ongoing climate change due to an elongated growing season and increased CO2 concentration.

References

1. Asseng, Senthold, et al. "Rising temperatures reduce global wheat
   production." Nature climate change 5.2 (2015): 143-147.
2. Boote, Kenneth J., et al. "Putting mechanisms into crop production
   models." Plant, cell & environment 36.9 (2013): 1658-1672.
3. Challinor, Andrew J., et al. "A meta-analysis of crop yield under
   climate change and adaptation." Nature climate change 4.4 (2014):
   287-291.
4. Rosenzweig, Cynthia, et al. "Assessing agricultural risks of climate
   change in the 21st century in a global gridded crop model
   intercomparison." Proceedings of the national academy of sciences
   111.9 (2014): 3268-3273.
5. Semenov, Mikhail A., Elaine M. Barrow, and A. Lars-Wg. "A stochastic
   weather generator for use in climate impact studies." User Man Herts
   UK (2002): 1-27.
6. Shawon, Ashifur R., et al. "Adapting the CERES model to simulate
   growth and production of cereal rye." Julius-Kühn-Archiv 471 (2022).

Speaker: Mr Ashifur Rahman Shawon (Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment)

128 Soil fertility change outweighs climate change impact on maize yield in sub-Saharan Africa, a multi-model study

1. Introduction.
   Sub-Saharan Africa (SSA) faces significant food availability issues largely due to low soil fertility leading to low crop yields. Climate change is expected to exacerbate these issues due to a combined negative impact on crop yield and soil fertility. Integrated soil fertility management (ISFM) implies the combined use of mineral and organic fertilizers and is seen as a solution to increase soil fertility and crop yield, yet it is uncertain how this advantage is maintained with climate change. Soil-crop models are useful tools to assess the performance of ISFM. Multi-model simulations are often more robust than single-model simulations and contribute to understanding and reducing modelling uncertainty (Falconnier et al., 2020).
   In this study, we aim to i) evaluate multi-model performances for long-term simulations of crop yield and soil organic carbon (SOC) and their feedbacks (Couëdel et al., 2024), ii) use the calibrated multi-model ensemble to explored the impact on maize yield for scenarios of change in soil fertility and climate variables in four representative sites in SSA with no input and ISFM management (Couëdel et al., submitted).

2. Materials and methods.
   We compared the performance of 16 soil-crop models using data from four long-term experiments at sites in SSA with contrasting climates and soils. Each site had experimental treatments including no exogenous inputs and ISFM. Once calibrated and evaluated we used the multi-model ensemble under reset and continuous simulations over 30 years to assess the impact of soil fertility vs change in climate variables (temperature, rainfall, and CO2) on crop yield. In reset simulations, SOC, soil nitrogen and soil water were reinitialized each year with the same initial conditions. In continuous simulations, SOC, soil N and soil water values of a given year were obtained from the previous year's simulation, allowing for cumulative effects on SOC and crop yields.

3. Results.
   Model ensemble evaluation show that uncertainty increased over the duration of the long-term experiments. SOC simulations uncertainty was largest when organic amendments were applied, whilst yield predictions uncertainty was largest when no inputs were applied. We found discrepancies among models in simulating soil-crop feedbacks due to uncertainties in simulated carbon coming from roots and simulated crop N supply from soil organic matter decomposition. Yet when used as an ensemble, the 16 models enable to reproduce with satisfactory accuracy yield and SOC dynamics in all sites.
   In the scenario analysis, most models agreed that with baseline management (no input) the magnitude of yield changed was much larger when considering declining soil fertility with baseline climate (-39%), compared with considering constant soil fertility but changes in temperature, rainfall and CO2 (from -12% to +5% depending on the climate variable considered) (Figure 1.A). The model ensemble showed that when changes in soil fertility were taken into account, the advantages of ISFM systems over no-input systems increased over time (+190%) (Figure 1.B). This increase in ISFM benefits was greater at sites with low initial soil fertility.

4. Discussion.
   We found that soil fertility changes had more impact than climate change on maize crop yield in SSA. We argue for the urgent need to consider long-term soil-crop feedbacks in climate change studies to avoid largely underestimating the impact of climate change and ISFM on food production in SSA. The model evaluation also emphasizes the need for long-term experiments in which root and soil N dynamics are monitored. This will provide the relevant data to improve and calibrate soil-crop models, leading to more robust and reliable simulations of SOC and crop productivity, and their interactions.

5. References.
   Couëdel, A., Falconnier, G. N., Adam, M., Cardinael, R., Boote, K., Justes, E., et al. (2024). Long term soil organic carbon and crop yield feedbacks differ between 16 soil-crop models in sub-Saharan Africa. Eur. J. Agron. 155. doi: 10.1016/j.eja.2024.127109.
   Couëdel, A., Falconnier, G. N., Adam, M., Cardinael, R., Ruane, A., Boote, K., et al. Soil fertility change outweighs climate change impact on maize yield in sub-Saharan Africa. Under review
   Falconnier, G. N., Corbeels, M., Boote, K. J., Affholder, F., Adam, M., MacCarthy, D. S., et al. (2020). Modelling climate change impacts on maize yields under low nitrogen input conditions in sub-Saharan Africa. Glob. Chang. Biol., 1–23. doi: 10.1111/gcb.15261.

Speaker: Antoine Couëdel (AIDA, Univ Montpellier, CIRAD, Montpellier, France ; CIRAD, UPR AIDA,)

Digital & AI

Conveners: Enli Wang, Tobias Reuter

129 Coupling experimentation and crop modeling to evaluate morpho-physiological traits of cotton cultivars in agroecological cropping systems in Benin

1. Introduction.
   Cotton is Benin's leading export crop grown in different climatic zones. As a result of poor farming practices in agroecosystems leading to a decline in soil fertility, coupled with the phenomenon of climatic hazards, seed cotton yields of cultivated varieties are low. Given the context of soil degradation, agroecological practices are proposed as an alternative to conventional cropping systems. The emerging challenge for breeders is therefore to select new cultivars adapted to innovative cropping systems (Gouleau et al., 2021). Crop simulation models can be used to assess growth and yield of different crop genotypes (G) in different environments (E) by using environment-specific weather, soil, and crop management (M) practices (Boote et al., 2001) and help understanding the direct effect of each plant trait or a combination of traits on the G by E interactions for crop yield and other complex traits. The objectives of this study were (i) to evaluate the relative contribution of plant traits driving the G by E by M interactions for cotton yield using CSM-CROPGRO-cotton model from DSSAT, and (ii) to identify morpho-physiological traits for yield enhancement in agroecological cropping systems in Benin.

2. Materials and methods.
   The experimental study was conducted from 2020 to 2023, in two sites (Savalou and Soaodou) representative of contrasted cotton-growing regions of Benin. Approach consisted of (1) carrying out field experiments for the calibration and validation of CSM-CROPGRO-cotton model and determining the yield performance of cotton genotypes (2) launching a sensitivity analysis of the genetic coefficients from the crop model to determine the best values for traits adapted to agroecological cropping systems. According to a split plot design, the experiment compared four cropping systems with cowpea/maize//cotton rotation, namely Conventional Tillage (CT) with a plough, Conventional Tillage with Incorporation of biomass (CTI), Conservation Agriculture with Strip Tillage (CA_ST) and CA with No Tillage (CA_NT). In the three innovative cropping systems (CTI, CA_ST, CA_NT), legumes (Crotalaria spp., Stylosanthes guianensis) were sown as relay intercrops with maize while cotton was sown as a sole crop. Six different cultivars originated from Benin, Argentina, Uzbekistan, Nicaragua, and USA were compared as subplots in every cropping system. Among other parameters, crop model was parameterized for soil properties and water dynamics, and calibrated for phenology and growth, using a dataset under optimal conditions, then evaluated on other data from the same sites and 2 years.

3. Results.
   The agreement between simulated and observed data was strong for extractable soil water (fig 1a), and LAI (fig 1b) but fair for seed cotton yields (fig 1c). Our results confirmed that CSM-CROPGRO can be used to simulate the growth and yield of cotton in different environments and cropping systems and for the estimation of genetic coefficients (fig 1d). The availability of soil nitrogen was better in agroecological systems. The cultivars TAMCOT_CAMDE, S188 and OKP768 resulted in higher yields in the agroecological cropping systems under CA. The traits LFMAX, SLAVR, FL-LF and PODUR were responsible for yield differences and GxExM interactions.

4. Discussion.
   Maximum leaf photosynthetic rate (LFMAX) is related to traits that maintain high photosynthesis (Boote et al., 2001). In fact, increasing the value of this trait resulted in a decrease of SLAVR, indicating leaf thickening for leaf types like okra S188 or TAMCOT_CAMDE ensuring better nitrogen mobilization and radiation use efficiency, especially in CA systems. Increased availability of nitrogen in CA_ST and CA _NT made it possible to maintain green leaf area, delayed senescence of leaves (FL-LF) and a longer accumulation of reserves during seed filling (PODUR) (Wells et al., 1982) leading to an increase of boll weight.

5. References.

6. Gouleau, A., Gauffreteau, A., This, P., Tailliez-Lefebvre, D., Gombert, J., Gouache, D., & Bakan, B. (2021). Saisine du Comité Scientifique CTPS-Quelles variétés pour l’agroécologie ? https://doi.org/10.17180/MEZ5-YV03.

7. Boote, K. J., M. J. Kropff, and P. S. Bindraban (2001). Physiology and modelling of traits in crop plants: implications for genetic improvement. Agric. Syst. 70, 395–420.
8. Wells, R., L.L. Schulze, D.A. Ashley, H.R. Boerma, and R.H. Brown. (1982). Cultivar differences in canopy apparent photosynthesis and their relationship to seed yield in soybeans. Crop Sci. 22:886–890.

Speaker: Mr Dègbédji Charlemagne ABOUA (IRC, CIRAD, INRAE)

140_Aboua.pptx

130 Envirotyping to drive spring barley adaptation in northwestern Europe

Introduction: Adapting crops to climate will be challenged by shifting environments and increasing weather instability impacting both yield potential and stability. Exploring genotype x environment interactions (GEI) sources at large scale to develop outperforming and stable genotypes is an important step. Defining the Target Population of Environments (TPE) across the crop production area – i.e., set of climatic scenarios minimizing GEI – is an approach to identify the specific or broad adaptation of a genotype to climatic scenarios. Crops models are powerful tools to accurately characterize crop environments and the origin of GEI (Chenu et al., 2011). Spring malting barley is a cereal crop largely understudied in plant ecophysiology. This biological model is distributed worldwide and cultivated under contrasting agro-climatic conditions, with a short cycle, lending vulnerability to climate change. Our study aimed to (i) highlight the main eco-climatic factors – climatic variables calculated between two growth stages – driving yield levels and GEI for yields and (ii) define the spring malting barley European Target Population of Environments (TPE) for crop adaptation.

Materials and Methods: Yield data from 2015 to 2022 were collected from an European multi-environment trials (MET) network. The phenology-calibrated CERES-Barley model (DSSAT) was used to calculate 91 eco-climatic factors from historical weather data to characterize each environment of the MET. Partial Least Squares (PLS) regression analyses were carried out to identify the main eco-climatic factors impacting yield levels and relative yields of genotypes across Europe (Elmerich et al., 2023). An environmental classification was performed based on the GEI-drivers across 1,450 environments, including tested and untested locations within the European area of production to define climatic scenarios minimizing GEI.

Results: Water stress was not identified as a major yield-driver. Results suggested an important contribution of cool temperatures at early stages to explain yields variation sources across the MET. Strong regional contrasts in the critical phenological stages for yield levels were observed. The grain filling period had the lowest influence on yields. Eco-climatic factors driving GEI differed from those of yields. Elevated temperatures during stem elongation, solar radiation and drought during grain filling shown a high contribution to GEI. Thermal amplitude around anthesis also emerged as influent. Three main environment types (ETs) were identified from the GEI-drivers and contrasted in their patterns of temperatures during vegetative growth, solar radiation intensity, and water stress during grain filling. The frequency of occurrence differed in time and space across Europe (Figure 1). Heterogeneity in genotype adaptations to environment types were observed, with genotypes having specific adaptation to one environment type while others with broad adaptation.

Discussion: Without limiting assumptions, this approach clarified the environmental sources of inter and intra-annual variability in yields. To adapt to climate change, agricultural practices will need to evolve to minimize exposure to adverse climatic factors during critical growth phases. Shift sowing can be used, but the crop may be exposed to potential critical factors during the short spring-summer season, which includes cold stress or waterlogging. The choice of adapted cultivars will also be a key decision, as their sensitivity to climatic factors differs. The drivers of GEI contrasted with those of yields, allowing the identification of three major environment types minimizing GEI. Performances of the existing germplasm across the TPE showed contrasted responses that can be directly used for product positioning. This work will help breeders to cope with GEI for spring barley breeding, by weighing trials using MET-TPE alignment, defining more efficient trial networks and designing ideotypes for specific or broad adaptation (Cooper et al., 2022).

References:
Chenu, K., Cooper, M., Hammer, G.L., Mathews, K.L., Dreccer, M.F., Chapman, S.C., 2011. Environment characterization as an aid to wheat improvement: interpreting genotype–environment interactions by modelling water-deficit patterns in North-Eastern Australia. Journal of Experimental Botany 62, 1743–1755. https://doi.org/10.1093/jxb/erq459

Cooper M, Messina CD, Tang T, Gho C, Powell OM, Podlich DW, Technow F, Hammer GL. 2023a. Predicting genotype × environment × management (G×Ex×M) interactions for design of crop improvement strategies: integrating breeder, agronomist, and farmer perspectives. Plant Breeding Reviews 46, 467–585. https://doi.org/10.1002/9781119874157.ch8

Elmerich, C., Faucon, M.-P., Garcia, M., Jeanson, P., Boulch, G., Lange, B., 2023. Envirotyping to control genotype x environment interactions for efficient soybean breeding. Field Crops Research 303, 109113. https://doi.org/10.1016/j.fcr.2023.109113

Speaker: Maëva Bicard (Institut Polytechnique UniLaSalle, AGHYLE)

131 Canopy anomaly classification using Hybrid ML, a case study on potatoes

Introduction

Crop canopy reflectance is often used as a proxy for crop vitality. While it relatively easy to identify low vitality spots through vegetation indices (e.g. NDVI, WDVI, etc.) automating the identification of the causes of the low vitality spots remains an unsolved challenge. In fact factors that can cause a drop (or an increment) in vegetation indices, for example water and nitrogen abiotic stress, and biotic stresses like soil and air-borne diseases, and weeds. The objective of this project is to create a model to detect the presence low vigor (e.g. poor spots on an NDVI map) and identify its cause for potato crops.

We are developing a hybrid model (Scientific ML) composed a recurrent neural network trained on a synthetic data set generated using a potato growth model (Tipstar), coupled to a canopy reflectance model(PROSAIL). The model will consume time series data of multispectral signatures as well as data on crop management (e.g. fertilization, water stress, maturity class), weather and soil to facilitate the identification of the anomaly. The appearance of different stresses at different times in the season will be a major driver of the predicted stress factor, for example low emergence will cause an initial decrease in canopy vigor indicators — like NVDI — that will decrease as the season proceeds and canopy will close. The model will be validated on experimental data described below.

Materials and methods

Field experiment dataset

In the first year two cultivars were cultivated over 6 plots without replicates and canopy reflectance was monitored bi-weekly through a hyperspectral sensor and a drone multispectral images, along with final yield and bi-weekly SPAD measurements. In the second year (2024) we are repeating the experiment with three replicates and two sites. Preliminary results from the second year of experiment will be presented.

Synthetic dataset

We generated a synthetic dataset of crop growth and its spectral canopy under multiple stress factors. Crop growth was simulated using Tipstar — a potato growth model — whereas canopy spectra was simulated using Prosail, a radiative transfer model.

The first dataset is a factorial in-silico experiment with the following factors: two sites, 10 different growing seasons, two cultivars (one early and one late cultivar), 5 stress factors.

No interaction between the stress factors was simulated (e.g. no low emergence and water stress in the same simulation).

The factors that were accounted for in the model are the following:

• Control was simulated as potential yield (no stress factor) by adding ample nitrogen fertilization and irrigation events

• Water stress was simulated by removing irrigation events

• Nitrogen stress was simulated by removing nitrogen fertilization events

• Low emergence was simulated by halving the number of emerged plants

• Weeds — a process that is not present in the crop model — was simulated by increasing the leaf area index input in the prosail parameter at the beginning and at the end of the season.

Modelling

The models are trained on the synthetic dataset and will be validated on the observed dataset. A first model serving as baseline for model comparison was developed based on difference between the observed NDVI and the NDVI of the simulated causes of anomalies.

Results from more complex models, based on recurrent neural network classification and multiple inputs (time series of reflectance at different wavelengths instead of crude indices like NDVI, management information) algorithms will be presented.

Results

Data from the first year experimentation (Fig.1) indicate that the time development of the different stresses, weed stress results in higher NDVI at the beginning of the season, nitrogen stress results in lower NDVI through the season, lower emergence in an initial decrease of NDVI that is recovered as the season proceeds, and individual plants expand.

Preliminary results from the baseline model indicate a good model fitness, with more difficulties in identifying the cause of stress in the middle of the season because of the saturation of the NDVI signal. Results from more complex models will be presented.

Figure 1: Results from year 1 of experimentation. NDVI (top) and NDVI percentage change compared to control for the two cultivars (Avenger, a late cultivar and Frieslander an early cultivar).

Speaker: Bernardo Maestrini (Wageningen University and Research)

132 Combining artificial intelligence and co-design to build scenarios for an agroecological transition of farming systems

Introduction

To address agricultural challenges, engaging agroecological transition is crucial, necessitating a redesign strategy for productive and resilient biodiversity-based farming systems. However, implementing spatio-temporal design of diversified systems is complex due to the diverse factors that need to be considered, the large number of possible crops combinations in time and space, and the need to combine different forms of knowledge to take account of operational constraints, soil and climate conditions, and agroecological objectives. To support the design of agroecological cropping systems, we propose to combine together AI (constraint programming) which provides formalisms with a high level of expressivity (Challand et al., 2023) with co-design approaches that enable stakeholders with diverse skills and knowledge to collaborate, while putting the farmer at the centre of the design ecosystem. This approach has been applied to one of the most complex agrosystems, the mixed orchard market gardens, to explore crop allocation scenarios with the farmer that take tree growth into account.

Materials, methods

The model AGROECOPLAN, used in this study to generates a spatio-temporal crop allocation solution, has been described in Challand et al (2023). The model is composed of four sets of constraints to take into account pedoclimatic, operational and agroecological constraints: respect the return time of crops, forbid negative spatial interactions (spread of pests, incompatible cultivation operations, shade from neighbouring crops or trees…), forbid unfavourable precedents, forbid impossible locations. The model then optimizes two criteria to propose a cropping plan that maximizes the positive spatial and temporal interactions between crops.

The model was used in a case study one-hectare micro-farm in South of France. The objective was to assign the 60 crops from the cropping calendar to the 80 cropping beds, considering the crop assignments of the last 3 years and the farm's pattern. The co-design workshops were conducted in three steps : (i) identify and formalise the problem through a semi-directive interview with the farmers (ii) run the AGROECOPLAN model to propose a crop allocation scenario (iii) evaluate with the farmer the model's output and performance. If the solution is deemed unsatisfactory, the set of constraints is modified with the farmers to better specify the problem and the model is run again (repeating step 2) until a satisfactory solution is found.

Results

The co-design workshops led farmers to formulate three issues that guided the exploration of the scenarios. (i) How to add the maximum green manure beds to improve the agroecosystem performances? (ii) How will the growth of fruit trees change the layout of crops in the future? (iii) What crop area is needed to satisfy all the farmers' expectations? The model was able to find solutions that satisfied all the constraints for each of these three issues. This required several iterations each time to better specify and prioritize the constraints.

To answer the first question, two green manures were selected with the farmers: fodder beet and forage rye. By maximizing the number of green manures, 10 fodder beet beds and 24 forage rye beds were introduced, increasing the total number of positive interactions between crops by 16%. By taking into account the growth of the trees, we have been able to adapt the cultivation plan over long time, allowing crops that need or tolerate shade to benefit from it. Finally, exploration of the scenarios to answer the third question showed that 7 additional cropping beds were needed to find a cropping plan that met all the farmers' expectations. This corresponds to a 9% increase in cultivated area, which was feasible in this case study.

Discussion.

By integrating constraint programming into a co-design approach, we effectively managed the complex combinatorial nature of designing highly diversified farming systems and took account of farm-specific constraints and farmer expectations. This process introduced a disruptive solution for farmers, providing a basis for discussion on how to evolve their practices in order to strike a balance between integrating agroecological principles and maintaining acceptable operational management. This makes it possible to integrate many internal (soil-plant interactions) and external (management practices, climate) regulations that underpin the resilience of agro-ecosystems.

References.

Challand, M., Vismara, P., Justeau-Allaire, D., and de Tourdonnet, S. (2023). Supporting Sustainable Agroecological Initiatives for Small Farmers through Constraint Programming. In "Proceedings IJCAI-23, Macao, S.A.R.

Speakers: Ms Margot Challand (ABSys, Univ Montpellier, CIHEM, Cirad, INRAE, Institut Agro Montpellier, Montpellier, France), Stéphane de Tourdonnet (ABSys, Univ Montpellier, CIHEM, Cirad, INRAE, Institut Agro Montpellier, Montpellier, France)

133 Deep learning with limited data availability: self-supervised learning for crop yield prediction using RGB drone imagery

1. Introduction:
   Deep learning-based methods have shown success in predicting crop yield. However, it is still a challenge to train a deep learning model to effectively predict crop yield with only a few labeled observations, especially across small agricultural fields with high heterogeneity. Self-supervised learning (Liu et al., 2021) is a new technique addressing the challenge, but no study has examined the potential for crop yield prediction. Our aim is to investigate the potential of self-supervised learning for yield prediction using RGB drone imagery across multiple crop types. This study explores the synergistic potential between self-supervised learning and RGB drone imagery to address this challenge.

2. Materials and Methods:
   Our study was conducted at the patchCROP agricultural landscape lab in Brandenburg, Germany, examining four summer crops (lupine, maize, soy, and sunflower) in 2020 (Grahmann et al., 2024). The research utilized high-resolution (~2.2cm) RGB images from UAVs, capturing the crops at the stages from late fruit development to ripening, across diverse small field arrangements (0.5 ha each). At each field, a combine harvester collected around 120 yield points. We employed the self-supervised learning algorithm, VICReg (Bardes et al., 2022), to train a deep learning model on a dataset comprising four crop types and multiple fields to learn key morphological patterns without using labels (amount of fields: lupine = 3, maize = 6, soy = 2, and sunflower = 3). Successively, we adapted the task of the same model for predicting crop yield. The prediction performance was compared to a conventional, supervised baseline model.

3. Results:
   A key empirical finding was the ability of self-supervised learning to distinguish between crop types without labels based on morphological features. For crop yield prediction, we evaluated the model performance in two ways. Self-supervised showed a high prediction performance when compared between observations and predictions regardless of crop types (Pearson’s r 0.83). When prediction performance was evaluated for each crop type, it decreased (lupine, r = 0.4; maize, r = 0.78; soy, r = 0.15; and sunflower, r = 0.43) but was still substantially better for three crop types than the conventional supervised learning model (lupine, r = 0.07; maize r = 0.9; soy, r = 0.07; and sunflower = 0.24). Overall, a median score of r for the self-supervised model was 0.42, and for the supervised model was 0.16.

4. Discussion:
   Our study demonstrates the promising potential of self-supervised learning in diversified agriculture. We showed that self-supervised learning can make use of large, unlabeled, combined image datasets across different crop and management types to discover key morphological patterns, and then the model can be used for crop yield prediction across crop types at good accuracy. This finding is important because currently so many deep learning models have been developed for different crop and management types independently. Self-supervised learning can unify the efforts and develop a more generalized model that can be applied in various cases. Yet, we also identified inconsistencies in prediction accuracy across and within crop types, emphasizing the importance of careful model evaluation and further development. Our findings advocate for the use of self-supervised learning to overcome data limitations and improve predictive modeling in small-scale agriculture.

5. References:
   Bardes, A., Ponce, J., and LeCun, Y. (2022). VICReg: Variance-Invariance-Covariance Regularization for Self-Supervised Learning. doi: 10.48550/arXiv.2105.04906
   Grahmann, K., Reckling, M., Hernández-Ochoa, I., Donat, M., Bellingrath-Kimura, S., and Ewert, F. (2024). Co-designing a landscape experiment to investigate diversified cropping systems. Agricultural Systems 217, 103950. doi: 10.1016/j.agsy.2024.103950
   Liu, X., Zhang, F., Hou, Z., Wang, Z., Mian, L., Zhang, J., et al. (2021). Self-supervised Learning: Generative or Contrastive. IEEE Trans. Knowl. Data Eng., 1–1. doi: 10.1109/TKDE.2021.3090866

Speaker: Stefan Stiller (Research Platform “Data Analysis & Simulation”, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany; Environment and Natural Sciences, Brandenburg University of Technology Cottbus‐Senftenberg, 03046 Cottbus, Germany)

134 Operational yield forecasting and crop management with a digital twin

1. Introduction

Crop growth models can provide real-time forecasts of upcoming drought or nutrient deficiencies and can thus in principle be used to support decisions about irrigation and fertiliser application. To be useful for supporting in-season crop management, forecasts need to be (1) frequently updated and (2) sufficiently accurate. This second point is problematic in practice, because crop models tend to deviate from reality, due to insufficient calibration, and because not all relevant processes are included. A digital twin (van Evert et al. 2021, Knibbe et al. 2022) combines crop growth modelling with updating model state variables based on in-season observations. A digital twin provides daily updated estimates of growth forecasts and also shows how these forecasts are corrected with observations. Ideally, such a digital twin results in greater forecasting accuracy, for the end-user more confidence in model predictions and ultimately more efficient resource management. We developed a fully automated operational digital twin for a strip cropping experiment in the Netherlands.

1. Materials and methods

The digital twin strip cropping (DTS) has the following properties:
1. Field experiment in centre of Netherlands, with in total 7 crops and 11 strips per crop. Not all crops were modelled
2. Strip specific management data retrieved through Farmmaps platform (Been et al 2023)
3. Location specific soil and weather data retrieved through Farmmaps
4. Bi-weekly drone flights. Stitching and geo-referencing by a private company then imported into relational database as soon as available
5. Two crop growth models used: Tipstar for simulating potato (early and late cultivar), and WOFOST for fababean, onion and winter wheat
6. Ensemble Kalman Filter (EnKF) adjusts model states based on LAI observations derived from drone images, taking into account both the uncertainty in the model (estimated by perturbating model parameters) and the uncertainty in the observation.
7. NMODCOM simulation framework for integrating different models and enabling EnKF
8. Forecasting by stitching weather till present date, a 14 day forecast, and thereafter from a year in the past (e.g. 1991, 1992, etc). Simulations are repeated 30x with 30 past years to get a plume visualising uncertainty due to future weather
9. Automatic running the digital twin overnight for all 5 crops x 11 strips x 30 weather combinations
10. R-scripts generated daily figures. A new website was developed to present the most recent forecasts every day.

1. Results

Figure 1 presents an illustration of forecasts presented to the farm manager. More daily updated figures are available from https://farmofthefuture.nl/data-precisietechnologie/gewasgroeimodellen/ (in Dutch).

Figure 1. Mid July 2024 forecast of Leaf Area Index (LAI) and tuber yield. Figure showing an ensemble of simulations (grey dots) and median of simulations (black line). Green dots show LAI estimates based on drone images. Four green dots in April-May were pre-emergence and ignored. Green dots mid-June and July cause a downwards correction of simulated LAI. Simulations continue with the downward adjusted LAI.

1. Discussion

The work presented represents one of the first operational digital twins in the agricultural domain. Farm managers showed greater appreciation for potential of models to support their decision making because we provided daily updated forecasts and visualized how these were updated with data from drone images (e.g. Fig 1).
Scientifically we are still in a pioneering stage. A major advantage of using a filter to update the state variables that it allows to correct the predictions for processes that are not currently in the model, e.g. canopy diseases. We are currently working on an advanced version of the digital twin where in addition to leaf area index also soil moisture is updated using satellite images.

1. References

Been, T.H., et al., 2023. Akkerweb and farmmaps: Development of Open Service Platforms for Precision Agriculture. In: D. Cammarano et al. (Eds.), Precision Agriculture: Modelling. Springer International Publishing, Cham. p. 269-293.
Knibbe, et al., 2022. Digital twins in the green life sciences. NJAS: Impact in Agricultural and Life Sciences 94, 249-279.
van Evert, F.K., et al., 2021. A digital twin for arable and dairy farming. In: J. Stafford (Ed.). Precision Agriculture '21. Wageningen Academic Publishers, Wageningen. p. 919-925.

Speaker: Frits Van Evert (Wageningen University & Research)

Towards sustainable management of weeds

Conveners: Reinhard Neugschwandtner, Alessandro Triacca

135 Which pea traits for agroecological weed management in pea-wheat intercrops

Introduction. Pea (Pisum sativum L.) is a key diversification crop but current pea varieties are not very competitive against weeds. Intercropping pea with cereals is a promising lever to reduce weed infestation and damages. However, past pea varieties were bred for sole crops usually in herbicide-protected fields. They may not be optimal for growing in intercrops with wheat and in the presence of weeds. The objective of this study was to identify, depending on the type of cropping system and weed flora, (1) the key pea parameters that drive crop production and weed control in pea when intercropped with wheat (Triticum aestivum L.), (2) optimal combinations of pea and wheat parameter values as well as intercrop management techniques (tillage, sowing date and density, interrow width…), to maximise these goals.

Material & Methods. Virtual experiments were run, using FLORSYS (Colbach et al., 2021). This mechanistic individual-based 3D model simulates daily crop-weed seed and plant dynamics over the years, from the cropping system and pedoclimate, focusing on plant-plant competition for light. The model includes five winter pea and three winter wheat varieties. Virtual varieties (5 pea and 10 wheat) were created by randomly combining variety-parameter values according to a Latin Hypercube Sampling (LHS) plan, respecting parameter ranges and correlations observed in the actual varieties. A global sensitivity analysis was run, using another LHS plan to combine pea and wheat varieties, crop rotations and management techniques in nine contrasting situations (e.g., conventional vs organic, no-till, type of weed flora). Simulated data were analysed with classification and regression trees (CART). Additional simulated data with sole-crop winter pea instead of pea-wheat intercrops were taken from Colbach et al. (2022).

Results. Intercropping reduced pea yield loss due to weeds (by 30% for the least weed-tolerant varieties, e.g. Enduro) and field infestation (by 14% for the least weed-suppressive varieties, e.g., 886-1). In wheat-pea intercrops, intercrop management and the pea variety were more influential than the wheat variety for yields. Yield loss due to weeds and field infestation depended mostly on the management of intercrops and other crops of the rotation, with little effect of variety parameters.

We highlighted (1) key pea parameters that drive potential (weed-free) yield and competitivity against weeds (e.g., biomass allocation to leaves until full maturity, increased plant width per unit biomass when shaded, frost tolerance). These are pointers for breeding varieties that regulate weeds in intercrops by better competing for light; (2) Rules to guide farmers to choose the best pea variety, depending on the production goal, the intercropped wheat variety and the cropping system (Figure 1). Pea and/or intercrop yields as well as weed suppression improved when pea ideotypes were tailored to cropping system types (e.g., always tilled vs never tilled), and combined with optimal wheat varieties and crop management (e.g., ideotypes y12 and y3 vs gy1-gy3). The best pea ideotypes had a small root system and prioritised above-ground plant growth and light interception, except in no-till where a large superficial root system left less soil moisture for superficial weed seeds (NT1 and NT2). Pea ideotypes based on CARTs searching for the best weed-infested pea or intercrop yield also produced the best weed-free yields and weed suppression (e.g., gy1-gy3 vs gp1-gp2, Y1 and Y23 vs P12 and P3 or F2). Contrasting pea ideotypes could achieve similar performances, if the associated wheat varieties and/or crop management rules were optimised (e.g., P12 vs P3). In summary, a high pea yield in weedy intercrops required a pea variety with a high yield potential combined with a weed-suppressive wheat variety and weed-preventive management.

Perspectives. The present pea-parameter rules provide guidelines for farmers to choose their pea varieties in cereal-legume intercrops and for breeders to screen existing germplasm collections and to identify traits for which the select during breeding.

Funding
INRAE
European Union's Horizon 2020 Research and innovation programme ReMIX (N 727217)
Horizon Europe IntercropVALUES (N°101081973)
ANR PPR SPECIFICS (ANR-20-PCPA-0008)
ANR PPR MoBiDiv (ANR-20-PCA-0006)
COPRAA funded by the Office Français de la Biodiversité (OFB)

References
Colbach et al. (2021) Field Crops Research. https://doi.org/10.1016/j.fcr.2020.108006
Colbach et al. (2022) Frontiers in Plant Science doi.org\10.3389/fpls.2022.809056

Speaker: Dr Nathalie Colbach (INRAE Agroécologie Dijon)

34_Colbach Nathalie - Pea ideotypes intercropping.pdf

136 Effect of sowing patterns and species proportions of cereal–legume intercrops on weed control

Introduction. Intercropping – several species cultivated in the same field for a significant part of their growing periods – is a key lever for weed control. The aim of this study was to evaluate, by simulations with the FLORSYS model, the effects of bispecific legume–cereal intercrops on weed dynamics and their impact on crop production, tested in the absence of nitrogen or water stress.

Material and methods. This study simulated: (1) seven species proportions for wheat (Triticum aestivum L.)–faba bean (Vicia faba L.) and barley (Hordeum vulgare L.)–pea (Pisum sativum L.) mixtures (hence "species-proportion design"), and (2) nine spatial sowing patterns for triticale (Triticosecale)–faba bean, durum wheat (Triticum durum Desf.)–faba bean and wheat–pea mixtures (hence "sowing-pattern design"). In both cases, mixtures were compared to their corresponding sole crops (controls). Intercrops and controls were inserted into rotations and simulated over 30 years and repeated with 10 climate scenarios from Toulouse (South-Western France), either without weeds or with a high-density weed flora typical of the region. Weed management was organic-based or with reduced herbicide use. Simulations were run with FLORSYS, a mechanistic individual-based 3D model which simulates daily crop-weed seed and plant dynamics over years, from the cropping system and pedoclimate, focusing on plant-plant competition for light (Colbach et al., 2021).

Results. Simulations showed that, in the absence of weeds, the yield per plant in intercrops varied from 13% of the sole-crop yield (pea–wheat mixture in the species-proportion design) to 173% (triticale–faba bean mixture in the sowing-pattern design). In average, intercropping reduced weed-free yield per plant by 42% for legumes and had no effect for cereals. When weeds were included in the simulations, the average legume yield per plant decreased by only 24% compared to sole legumes, whereas the average cereal yield per plant decreased by 18%. In other words, the more competitive cereals protected legumes against weeds in intercrops but suffered more from weed competition than in sole cereals. Indeed, the weed biomass in intercrops was greater than or equal to that of the sole cereals, and less than that of the sole legumes (Figure 1.A and B). The intercrops that best controlled weeds were barley–pea and triticale–faba bean.

In presence of weeds, the spatial pattern alternating one cereal row with one legume row (50% cereal–50% legume) as well as the 67% cereal–33% legume and the 100% cereal–50% legume in the species-proportion design were those that both maximised yields of both legumes and cereals and minimised losses due to weeds (Figure 1. C and D). Additive designs were not more weed-suppressive than substitutive designs.

Conclusion and Perspectives. The present study highlighted the value of intercropping for weed management, and identified sowing proportions and sowing patterns depending on the objectives being pursued. In the presence of weeds, legumes benefitted more from intercropping than cereals because legumes are less competitive against weeds. This work will be extended to other species mixtures and management methods in order to better integrate farmers' practices and in contexts where water and nitrogen may be limiting. This work will thus contribute to help designing innovative cropping systems by integrating, among other things, the resilience of the systems designed in the face of climate change, using an agro-ecological approach to weed management.

Reference
Colbach, N., Colas, F., Cordeau, S., Maillot, T., Queyrel, W., Villerd, J., Moreau, D., 2021. The FLORSYS crop-weed canopy model, a tool to investigate and promote agroecological weed management. Field Crops Research 261, 108006. https://doi.org/10.1016/j.fcr.2020.108006

Funding
INRAE
European Union's Horizon 2020 Research and innovation programme ReMIX (N 727217)
Horizon Europe IntercropVALUES (N°101081973)
ANR PPR SPECIFICS (ANR-20-PCPA-0008)
ANR PPR MoBiDiv (ANR-20-PCA-0006)
COPRAA funded by the Office Français de la Biodiversité (OFB)

Speaker: Dr Nathalie Colbach (INRAE Agroécologie Dijon)

35_Colbach Nathalie - Species prop intercropping.pdf

137 Intercropping chickpea with a mechanically controlled service plant: a promising way to manage weeds while mitigating interspecific competition

1. Introduction
Grain legumes are key species for the agroecological and dietary transitions due to the numerous services they can provide. However, they are known to be weak competitors against weeds leading to unstable yields. For instance, chickpea (Cicer arietinum) is one of the most commonly grown grain legumes worldwide but suffers from major yield losses because of its poor competitive ability against weeds. Besides, few references are available under European pedoclimatic conditions since chickpea is a marginal crop in Europe. Intercropping has been proved to be a relevant lever to control weeds but can cause yield losses in the main crop (Cheriere et al., 2020). Mechanically controlling the associated species could limit its negative impact on the main crop. This study investigates whether intercropping chickpea with a mechanically controlled service plant allows to facilitate its production by improving the competitive ability against weeds while mitigating interspecific competition.

2. Materials and methods
A field experiment (2023, 2024) was conducted in western France on chickpea-based intercrops. We selected five species of service plants varying in their morphological, physiological and phenological traits: spring oat (Avena sativa), faba bean (Vicia faba), white mustard (Sinapis alba), Sudan grass (Sorghum x drummondii) and Egyptian clover (Trifolium alexandrinum). Chickpea was sown at the recommended density in rows spaced 33 cm apart. In the intercrops, the service plant was sown in chickpea’s inter-row at 50% of the recommended density. Chickpea’s inter-row (service plant, weeds) was either mowed at the beginning of chickpea flowering or left without mechanical control. The selected service plants were contrasted in their response to mowing depending on their ability to regrow (oat, Sudan grass, clover) or not (faba bean, mustard) after being mowed. The experiment was arranged in four randomized complete blocks. Ground cover, accumulation of dry matter (chickpea, service plant, weeds) at 6 sampling dates (5 and 10 leaves, beginning and end of flowering, grain filling, harvest) and N content were measured. Grain yield and thousand grain weight (TGW) were also determined.

3. Results
Our results showed that weed control was the highest when chickpea was intercropped with oat reaching a weed biomass (14 g/m2) lower than the sole crop (82 g/m2) and three other mixtures (59 - 84 g/m2) at the end of flowering. Mowing the inter-row induced a lower weed biomass but only at the sampling date two weeks after the operation. Oat is the only service plant that affected chickpea’s yield dropping from 4 t/ha (sole crop) to 1.5 t/ha with fewer grains and a higher TGW. Mowing the inter-row had no effect on total grain yield and number of grains produced but did induce a higher TGW.

During crop establishment, oat accumulated more biomass (Fig. 1) and nitrogen than the other service plants. At the beginning of flowering, chickpea had a lower biomass and N content in the intercrop with oat than the other treatments. When the inter-row was mowed, chickpea biomass and N content measured at grain filling stage tended to be higher in the mixtures with oat and clover. The chickpea/oat intercrop covered the soil faster but reached a lower final ground cover than the other treatments.

4. Discussion
The intercrops that included a service plant with a delayed biomass production, ground cover and N acquisition compared to oat reached the same level of weed control than the sole crop despite having a higher final ground cover. An early competitive ability against weeds is therefore necessary to guarantee an effective weed control later on in the cycle. In our study, mowing the inter-row did not have a lasting effect on weed biomass.

Oat’s interspecific competition affected not only weeds but also chickpea. It led to a low yield with fewer grains and a higher TGW. The higher TGW observed when the inter-row was mowed without affecting the number of grains shows that we managed to mitigate the competition exerted on chickpea regardless of the associated species. The increasing trends in chickpea biomass and N content in presence of mechanical control support this observation. Overall, this study provides further knowledge on mechanical control as a lever to manage trade-offs between services in intercrops.

5. References
Cheriere et al., 2020. Field Crops Res., 256.

Speaker: Margaux Guy (LEVA, Ecole Supérieure des Agricultures (ESA), INRAE, 55 rue Rabelais, F-49007 Angers, France)

90_Guy.pptx

138 Soil N dynamics and soil moisture after mechanical weed control in organic maize cultivation

1. Introduction
Mechanical weed control is a major element of weed suppression in organic farming systems. In addition to the direct effect on weed growth, mechanical weeding, such as harrowing or hoeing, is known to induce side effects on several soil- and crop-related properties. There is a lack of knowledge regarding the effect of mechanical weeding on soil N dynamics and soil moisture in organic maize cultivation after a legume-rich ley (Gilbert et al. 2009). In the context of efficient use of resources and increasing occurrence of extreme weather events (e.g., drought, heavy rainfall), the impact of mechanical weeding needs to be further examined and reconsidered.

2. Material and methods
A field trial was conducted in two consecutive years (2021, 2022) on a sandy loam in North-West Germany to investigate the impact of mechanical weeding on soil mineral nitrogen (SMN), soil moisture and crop yield in silage maize (Zea mays L). The previous crop in both trial years was grass-clover (Lolium multiflorum LAM., Trifolium pratense L.). Mechanical weed control was performed by harrowing or hoeing three times per growing season and compared to a control treatment without soil disturbance. The two treatments (mechanical weeding (mech): harrowing or hoeing; chemical weeding (chem): herbicide) were arranged in a randomised block design with four replications. For investigating SMN, disturbed soil material was taken from 0-5 and 5-20 cm soil depth directly before harrowing or hoeing and two and four days afterwards, respectively. Additionally, soil samples were taken at greater depths (0-30, 30-60, and 60-90 cm) before sowing and after harvest to calculate net N mineralization according to Kühling et al. (2023). Soil water content was first determined gravimetrically by drying a subsample of each soil sample and then volumetrically using the bulk density determined in field. Maize was harvested manually as whole plants. Weed coverage was determined directly before each mechanical weed control and at harvest using a Goettinger Schaetzrahmen (0.1 m²).

3. Results
In 2021, several events were observed where SMN was up to 47 % lower after mechanical weeding in 0-5 cm soil depth compared to the chemical treatment (32.59 kg ha^-1), while in 2022, SMN in 0-5 cm was significantly different between treatments in only one event (12.60/16.05 kg ha^-1; mech/chem). Mechanical weeding did not affect SMN in 5-20 cm soil depth but led to higher volumetric water content (VWC) in both soil depths, with differences between years and days of measurement (fig. 1). Both treatments (mechanical and chemical) did not completely suppress weed growth. Weed cover was significantly higher for the mechanical treatment at the third measure (12.67 %) and at harvest (10.07 %) in 2021 than for the chemical treatment (1.42/1.18 %), while no significant effect of the different treatments on weed cover was observed in 2022 (2.88/3.6 %; chem/mech). Net N mineralization and biomass yield were not affected by the different weed control treatments.

4. Discussion
The incorporation of grass-clover residues before sowing enhanced N mineralization, which was indicated by a high net N mineralization and high SMN content in both soil layers and years. Furthermore, compared with those of the chemical control, significantly higher weed coverage was observed for mechanical weeding in 2021 after the third treatment and at harvest. Low temperatures at the time of sowing could have delayed maize development and benefitted weed growth. These results indicate that the difference in SMN content between mechanical and chemical weeding around the third treatment (hoeing) may have occurred due to higher N uptake by weeds in the mechanically weeded plots. In 2022, no difference in weed growth was observed between the treatments, which was also reflected in similar SMN contents. In our study, higher VWC after mechanical weeding was attributed to improved water infiltration. Superficial soil disturbance by mechanical weeding following conventional tillage could have been beneficial due to disrupting the soil crust after rainfall.

5. References
Gilbert PA, Vanasse A, Angers DA (2009) Harrowing for weed control: Impacts on mineral nitrogen dynamics, soil aggregation and wheat production. Soil Tillage Res 103:373–380.

Kühling I, Mikuszies P, Helfrich M, et al (2023) Effects of winter cover crops from different functional groups on soil-plant nitrogen dynamics and silage maize yield. European Journal of Agronomy 148.

Speaker: Mareike Beiküfner (Osnabrück University of Applied Sciences)

139 Which tillage to limit regrowth of perennial weeds from storage-organ fragments? From field experiment to modelling

Introduction.
Management of perennial weeds has become increasingly difficult with the reduction of herbicide use. Perennials accumulate reserves in belowground storage organs from which they can regenerate new plants after a disturbance. Tillage is a key lever to control perennial weeds because it destroys the aboveground part and fragments the belowground storage organs, stimulating the regrowth of new shoots that use and thus reduce the reserves. Field studies suggest that the tillage tool’s features influence perennial-weed control. However, the underlying mechanisms of these effects need to be further investigated, especially the fragmentation of perennial storage organs by tillage tools. The objectives of this study were to 1) analyse how different tools fragment the creeping roots of Cirsium arvense (L.) Scop, one of the most problematic perennial species in arable crops, 2) combine existing knowledge in a predictive model to identify and rank the most important factors driving post-tillage regeneration of perennial weeds from fragments of their storage organs.

Material & Methods.
A field trial was conducted in Dijon in 2022-2023 to sample C. arvense root fragments left in the soil after single passages by five contrasting tillage tools (mouldboard plough, rotary harrow, chisel plough, horizontal cultivator and disc harrow). The fragments were measured and the distribution of root-fragment lengths was analysed for each tool with regard to their features (blade type, power take-off drive and working depth). By combining the results of this experiment and data from literature on the other processes involved, a model for predicting the regeneration rate of perennial weeds after tillage from fragments of their storage organs was built. Regeneration was successful when the belowground shoot produced by a fragment was long enough to emerge. The model was applied for different scenarios combining two tillage tools, two soil structures, two storage-organ distributions in the soil, two soil temperatures, two fragment diameters and two levels of maximal shoot length per unit fragment biomass (Figure 1).

Results.
In the experiment, the distribution of fragment lengths varied with tillage tool: rotary harrow left the smallest and least variable fragment lengths (3.7 cm on average), mouldboard ploughing the largest and most variable ones (12.7 cm on average and up to 30 cm). The three other tools produced intermediate-sized fragments (8-10 cm on average).
According to the model, fragment diameter and maximal shoot length per unit fragment biomass were the main determinant of regeneration rate: fragments were 32% (respectively, 29%) more likely to regenerate when their diameter (respectively, their maximal shoot length) doubled. The choice of the tool also had a significant impact: there were 13% less regenerated fragments after a rotary harrow than after a mouldboard plough. Soil structure and storage-organ distribution in the soil had a minor impact while soil temperature had no impact.

Discussion.
The length distributions of C. arvense root fragments depending on the tools were consistent with the scarce previous work (Leblanc & Lefebvre, 2018). The important role in the model of fragment weight and maximal shoot length in regeneration was in line with previous work on emergence (Torssell et al., 2015) and highlighted that the regrowth potential of perennial species are key drivers which need to be investigated further. Finally, the model showed differences between the tools: rotary harrow induced a lower regeneration rate from fragments than mouldboard plough, which was probably linked to a higher fragmentation rate (Bergkvist et al., 2017). However, to compare the overall effect of different tillage tools on perennial-weed control, the present model needs to be supplemented with formalisms predicting the regeneration rate of the unfragmented storage organs, located below the tillage depth.

Funding.
French Ministries in charge of Ecology, Agriculture, Health and Research
ANR PPR BeCreative (ANR-20-PCPA-0001)
COPRAA funded by the Office Français de la Biodiversité (OFB)

References.
Bergkvist et al. (2017). Control of Elymus repens by rhizome fragmentation and repeated mowing in a newly established white clover sward. Weed Research. https://doi.org/10.1111/wre.12246

Leblanc, M., & Lefebvre, E. M. (2018). Impact de différents outils de travail du sol sur le système racinaire du chardon et du laiteron. https://irda.blob.core.windows.net/media/5365/leblanc-lefebvre-2018-impact_de_differents_outils_de_travail_du_sol_sur_le_systeme_racinaire_du_chardon_et_du_laiteron.pdf

Torssell et al. (2015). Modelling below-ground shoot elongation and emergence time of Sonchus arvensis shoots. Acta Agriculturae Scandinavica. https://doi.org/10.1080/09064710.2015.1044463

Speaker: Solèmne Skorupinski (INRAE Agroécologie Dijon)

10:35 AM Coffee break

Adapting farming systems to changing of environmental conditions

Conveners: Antonio Delgado, Romane Mettauer

140 Characterising the interactive effects of photoperiod and vernalising temperature on the flowering time responses of pasture legumes

Introduction:
The use of subterranean clover (Trifolium subteranneum L.), an annual pasture legume, combined with correction of soil phosphorus (P) deficiency has led to major improvements in the productivity of both livestock and crop production systems in southern Australia. The climate across this region ranges from Mediterranean through to temperate. Under these conditions, annual plants need to flower at an optimal time in spring to minimise the exposure of flowers and young seeds to frost, whilst also ensuring that seed development and maturation has occurred prior to the onset of the hot, dry conditions of summer. Subterranean clover cultivars with appropriate flowering times have been selected to fit the range in growing season lengths (~5-9 months) across this large agricultural zone. Serradella species (Ornithopus spp.) are viable alternatives to subterranean clover and offer an opportunity to diversify the legume base of these pastures, but there are gaps in the availability of cultivars with flowering times that will fill all climatic niches. Certain serradella cultivars also lack stable flowering dates (Boschma et al. 2019) and this is a problem for species persistence in self-regenerating pastures. Flowering responses to low (vernalising) temperatures and photoperiod essentially determine flowering date. The aim of this study was to characterise the nature of the interaction between a cultivar’s flowering time response to photoperiod and its response to vernalisation and to understand how this interplay influences the time of flowering by each cultivar.

Key words:
Phenology, adaptation, persistence, temperate, climate

Materials and methods:
Two cultivars of yellow serradella (O. compressus L., ‘Yellotas’ and ‘Avila’), French serradella (O. sativus Brot., ‘Erica’ and ‘Serratas’) and subterranean clover (‘Coolamon’ and ‘Goulburn’) were subjected, in controlled-environment plant growth chambers, to ‘vernalised’ (9 weeks at 5 oC), or ‘unvernalised’ treatments (0 weeks at 5 oC) followed by five photoperiod treatments (11, 12, 13, 14 or 15 h with a weighted mean daily temperature of 18 oC). Appearance of the first flower was measured using thermal time from sowing to first flower (oC d). Critical photoperiods were defined for each cultivar by identifying the minimum photoperiod at which there was no additional decrease in time to flower for unvernalised plants when grown under longer photoperiods. A reverse sigmoidal function was fitted to the data from this experiment and data from a historic dataset (Goward et al. 2023). This model described how time to flower by unvernalised plants was modified by growth in photoperiods from 8 to 20 h.

Results:
Differences were observed between the cultivars in the time to flower when unvernalised and grown in short photoperiods. Under relatively short photoperiods, the ‘vernalised’ treatment was sufficient to reduce time to flower to a minimum, reflecting the intrinsic earliness of each cultivar. Growth in photoperiods ≥12 h reduced the need for vernalisation to promote earlier flowering. This interaction between responses to photoperiod and to vernalisation differed among the cultivars with some cultivars expressing different critical photoperiods (13 or 15 h). The reverse sigmoidal model described the interaction of photoperiod and vernalisation responses reasonably well and indicated differences among cultivars in the rate at which the response to photoperiod would override the need for vernalisation.

Discussion:
This study showed that if plants are not fully vernalised after a mild winter, increasing photoperiods during spring (>12 h) will override the need for vernalisation. This should permit the plant to still flower in a timely manner. As such the interaction of a cultivar’s responses to photoperiod and vernalisation provides a safeguard mechanism that protects flowering and seed production. The cultivar-specific responses observed in this experiment indicate there may be significant challenges for modelling flowering time of individual genotypes because of the considerable time and resources required to parameterise factors such as the critical photoperiod of each genotype/cultivar.

References:
Boschma S, Kidd D, Newell M, Stefanski A, Haling R, Hayes R, Ryan M, Simpson R (2019) Flowering time responses of serradella cultivars. In ‘Proceedings of the 2019 Agronomy Australia Conference’, Wagga Wagga, Australia.

Goward LE, Haling RE, Smith RW, Penrose B, Simpson RJ (2023) Flowering responses of serradella (Ornithopus spp.) and subterranean clover (Trifolium subterraneum L.) to vernalisation and photoperiod and their role in maturity type determination and flowering date stability. Crop and Pasture Science 74, 769–782. doi:10.1071/CP22366.

Speaker: Laura Goward (CSIRO)

ESA_Laura_Goward_240820_final.pdf

141 Comparison of organic and conventional crop management in Estonia since 2008

The aim of agriculture is to produce food of high nutritional quality in sufficient quantity, while being sustainable and taking care of the soil.

The aim of this study was to compare and analyse the impact of organic and conventional growing systems within the same rotation to the yield and quality of spring barley, red clover, winter wheat, field pea and potato, as well as to assess the soil nutrient content and microbiological diversity in time.

The field experiment was established on 2008 on the experimental field of the Estonian University of Life Sciences (58o 22´ N, 26o40´E) and the data has been collected since. Soil type is Stagnic Luvisol (sandy loam surface texture, C 1,38% and N 0,13%, pHKCL 6,0). The field was divided by nitrogen treatments: three different treatments in organic plots (Org0, OrgI with winter cover crops, and OrgII with winter cover crops and manure) and four different treatments in conventional plots receiving mineral nitrogen (N0, Nlow, Naverage, and Nhigh). The five-field crop rotation was based on following order: spring barley with undersown red clover, red clover, winter wheat, field pea, potato.

The average yield in organic system was generally lower compared to conventional system. However, in organic systems, the yield was the most stable. The most fluctuating cropping system was the most intensively managed N3. Protein content was in positive correlation with mineral nitrogen rate. Winter wheat protein content was the highest in N2 and N3, which received 100 and 150 kg of N/ha. Flour water absorption and dough development was the best in conventional treatments with higher N rate. However, dietary fiber content (beta-glucan and arabinoxylan) was only impacted by yearly temperature and precipitation and it did not depend on fertilization. The biomass and diversity of weeds was higher in organic systems, being the highest in Org I by the end of the second rotation. This indicates that the cover crops were not as suppressive as expected.

The content of all studied macronutrients in the soil has decreased over the years. The soil nitrogen content was the least affected by the treatment with cattle manure in organic system. The greatest nitrogen loss was from the soil of conventional treatment with the highest nitrogen rate. The potassium content of the soil decreased the most. The most sustainable in terms of soil fertility was the manure treatment in the organic system, while the conventional system with the highest nitrogen rate was the most vulnerable. Biodiversity and abundance of soil microorganisms depended on soil carbon content. The microbial diversity and abundance increased during the second rotation in most treatments. Decrease in bacterial diversity was seen N0 and N3. Treatments with low to average mineral nitrogen input were favourable for soil microbes

Ground beetle abundance and diversity was also higher in organic treatments. The highest values were detected in Org II, where cover crops and cattle manure was used. The most of the springtails was detected in Org II and N2 treatments, correlating with the higher organic matter content in soil. Treatment N0, where organic matter content was low and pesticides had further inhibiting effect, contained the smallest number of springtails.
Overall, the organic treatment with the winter cover crop and the cattle manure, despite the lower yields, provided the stability and the highest values in biodiversity measurements in weeds, ground beetles and springtails. Conventional treatments with the medium mineral nitrogen input resulted in the higher yield and acceptable quality and it was also favourable to biodiversity in soil and among springtails.

References:
Keres et al 2020 Long-term effect of farming systems on the yield of crop rotation and soil nutrient content. Agricultural and Food Science;
Keres et al 2021 The Combined Effect of Nitrogen Treatment and Weather Conditions on Wheat Protein-Starch Interaction and Dough Quality;
Korge et al. 2023. The influence of cropping system, weather conditions and genotype on arabinoxylan content in wheat and barley grains. J. Cereal Sci.;
Khaleghdoust et al. 2024. Barley and wheat beta-glucan content influenced by weather, fertilization, and genotype. Front. Sustain. Food Syst.;
Esmaeilzadeh-Salestani et al 2021 Cropping systems with higher organic carbon promote soil microbial diversity, Agriculture, Ecosystems & Environment

Speaker: Evelin Loit-Harro (Estonian University of Life Sciences)

297_Loit-Harro.pptx

142 Perennial crops shape the soil microbial community and increase the soil carbon in the upper soil layer

Soil biodiversity is threatened by intensive agriculture that relies on annual grain crop production, thus leading to a decline in soil functions and ecosystem services. Perennial grain crops have a positive impact on the soil microbial community, but the responsive microbial groups and the magnitude of their response remain uncertain. To better understand how soil microbial community composition is influenced by different crops and their management, we analysed soil microbial biomass and community composition, bacterial growth and soil total carbon in five cropping systems: organic perennial intermediate wheatgrass (IWG, Thinopyrum intermedium, Kernza®) sole cropping, organic IWG-alfalfa intercropping, organic biennial grass-legume mixtures ley cropping, organic annual wheat or rye cropping and conventional annual wheat cropping. The analysis was carried out at three time points under two growing seasons at four different soil depths. After five years, the IWG sole crop had greater amounts of soil total fungi and bacteria, arbuscular mycorrhizal (AM) fungi, saprotrophic fungi and gram-negative (G-) and gram-positive (G+) bacteria compared to annual wheat. Crop perenniality influenced the soil microbial community structure although precipitation, soil temperature and water content were the main drivers of the patterns and temporal variations of the microbial community assembly. Perennial crops with inherent long-term land cover together with reduced tillage and low nitrogen input management increased the proportions of fungi relative to bacteria, AM fungi to saprotrophic fungi, G- bacteria to G+ bacteria, and the growth rate of total bacteria. This resulted in a more active soil microbial community with higher microbial biomass than annual wheat, which contributed to the increased soil total carbon storage in 0-30 cm soil layer in a Scandinavian climate. The findings emphasize the importance of combining a no tillage strategy with long-term vegetation cover to increase soil quality, which in turn potentially improve the delivery of final ecosystem goods.

Speaker: Ms Shoujiao Li (Swedish University of Agricultural Sciences)

249_Li.pptx

143 Impact of climate change on maize productivity and nitrogen cycling in the sub-humid tropics: a field case study under rainfall extremes in Zimbabwe

Changes in rainfall patterns and extreme wet and dry events are more frequent and will intensify globally because of global warming disrupting the water cycle (Rohde, 2023). This is particularly the case in Southern Africa with an increasing intensity and frequency of rainfall extremes. These events often lead to water stresses ranging from droughts to waterlogging, which may adversely impact the soil-crop processes (Kim et al., 2024) and reduce crop productivity and nutrient use efficiency. However, studies using rainfall manipulation experiments remain scarce. Most of such existing experiments have been conducted on natural ecosystems such as grasslands and woodlands in the northern temperate regions, with a clear gap on croplands in the tropics and poor focus on interactions with nutrient cycling (Beier et al., 2012).
To better understand the soil-crop nitrogen (N) dynamics under rainfall extremes, a field-scale rainfall manipulation experiment has been carried out in 2022-2023 and 2023-2024 cropping seasons in Harare, Zimbabwe (17°42'13.5"S 31°00'29.4"E) under sub-humid conditions. This is a part of a large 1.5 ha new long-term experiment established since November 2022 and registered within the Global Long-Term Agricultural Experiment Network (https://glten.org/experiments/368). Three main rainfall treatments replicated three times were established: reduced rainfall (-30%), normal rainfall and heavy rainfall (events of 100 mm/24h). The reduced rainfall treatment is achieved with an exclusion system above the maize canopy using transparent shelters covering about 30% of the plots surface. The heavy rainfall events are simulated with an irrigation system, and two events are applied per cropping season. Within these rainfall treatments, the study focused on four cropping systems treatments, resulting from the combination of two N fertilization levels (0 and 80 kg N ha-1 yr-1), with or without mulching (0 and 6 t DM ha-1 yr-1). A bare soil treatment was also set up and monitored to study the soil functioning without crop. Key variables related to biomass production and N dynamics such as leaf area index, crop biomass and N uptake, yield, soil temperature, soil water and mineral N, mulch decomposition, and emissions of nitrous oxide (N2O) were monitored from the first cropping season. An in-situ experiment using 15N labelled fertilizer was conducted during the second cropping season to study the fate of fertilizer under the three rainfall treatments with and without mulch. Labelled N fertilizer was applied on microplots as basal application, first and second topdressing using non-cumulative split application approach with both soil and plant N and 15N monitoring at different stages of plant growth.
The first-year results indicate that N dynamics in the soil were slightly affected by rainfall treatments and the presence of mulch. Total aboveground biomass and grain yield were negatively affected by reduced rainfall and absence of N fertilization. Mulch exhibited a buffering effect in topsoil layers, reducing soil temperature variations and maintaining moisture for a longer period during dry spells. The decomposition kinetics of the mulch were little affected by rainfall treatments but was quick, with 50% of initial dry mass decomposed in about 70 days. These results suggest a highly variable impact of rainfall extremes on biomass production, maize residue decomposition and N cycle depending on their timing, intensity and frequency of occurrence. Results from plant N uptake and from the ongoing analysis of the 15N labelling experiment, along with the planned modelling work with the STICS soil-crop model should provide further clarification on the interaction between rainfall patterns and N cycle, as well as the short and long-term consequences on plant biomass production and recycling.

References
Beier, C., Beierkuhnlein, C., Wohlgemuth, T., Penuelas, J., Emmett, B., Körner, C., ... & Hansen, K. (2012). Precipitation manipulation experiments–challenges and recommendations for the future. Ecology letters, 15(8), 899-911.
Kim, Y. U., Webber, H., Adiku, S. G., Júnior, R. D. S. N., Deswarte, J. C., Asseng, S., & Ewert, F. (2024). Mechanisms and modelling approaches for excessive rainfall stress on cereals: Waterlogging, submergence, lodging, pests and diseases. Agricultural and Forest Meteorology, 344, 109819.
Rohde, M. M. (2023). Floods and droughts are intensifying globally. Nature Water, 1(3), 226-227.

Speaker: Mr Abderrahim Bouhenache (Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France)

144 Variability in arbuscular mycorrhizal fungi abundance and diversity within cocoa-based (Theobroma cacao L.) agroforestry systems across pedoclimatic conditions

1. Introduction. In the context of global challenges such as climate change, declining soil fertility, and the aging of cocoa orchards, the sustainable production of cocoa in West Africa is under significant threat (Ameyaw et al., 2018). As the region contributes over 70% to the world's cocoa supply, these challenges call for a profound reevaluation of conventional agronomic practices. This requires looking into innovative sustainable cultivation strategies that can bolster crop resilience, enhance soil health, and ensure economic viability for cocoa farmers. Arbuscular mycorrhizal fungi (AMF), which form symbiotic relationships with the roots of cocoa plants, offer a promising mechanism for achieving these goals. The symbiosis between cocoa plants and AMF can play a pivotal role in enhancing nutrient uptake, improving water retention, and increasing resistance to pathogens and environmental stressors (Leye et al., 2015). Given the diverse and complex ecosystems within which cocoa is cultivated, understanding the dynamics of AMF within cocoa agroforestry systems is crucial for developing sustainable agricultural practices.

2. Materials and methods. This study adopts an innovative methodological approach to assess the impact of agricultural practices on arbuscular mycorrhizal fungi (AMF) communities associated with cocoa plants. Composite soil samples were collected from 110 cocoa agroforestry plantations across the entire cocoa production zone in Côte d'Ivoire. The collected samples were analyzed to determine soil physicochemical properties and AMF spore density. Spore extraction was performed using the wet sieving method as described by Gerdemann and Nicolson (1960). After extraction, the spores underwent meticulous counting and detailed morphological analysis.

3. Results. The analysis of the total density of the spore after wet sieving of soil samples from 110 different cocoa plantations revealed significant variations in spore density between the sampling sites (p<0.05). This variability extends to the species richness of mycorrhizal fungi, which was observed to differ among cocoa plantations. Notably, the genus Glomus, Acaulospora, and Gigaspora emerged as the most frequently encountered across the sites. Furthermore, soil pH was found to directly influence mycorrhizal spore abundance, with a notable correlation identified. Specifically, slightly acidic pH conditions (pH <7) were found to adversely impact spore density, suggesting a sensible balance between soil acidity and the thriving of mycorrhizal fungi populations.

4. Discussion. In alignment with previous studies, the abundance and diversity of the natural communities of arbuscular mycorrhizal fungi are largely influenced by the soil properties in cocoa-based agroforestry systems. The genus Glomus, Acaulospora, and Gigaspora have been identified as generalist symbionts prevalent in numerous rhizospheres highlighting the significant role of soil physicochemical properties on the diversity and abundance of mycorrhizal spores (Pontes et al., 2024). Notably, low soil pH is shown to adversely affect spore density (Droh et al., 2022), underscoring the intricate relationship between soil health and the symbiotic interaction with cocoa plants. The presence of Acaulospora across different sites illustrates the potential of specific AMF species in enhancing plant health and soil fertility, thereby advocating for the integration of AMF-based strategies into cocoa agroforestry management.

5. References

Ameyaw L.K., Ettl G.J., Leissle K., and Anim-Kwapong G.J. (2018), Cocoa and climate change : insights from smallholder cocoa producers in Ghana regarding challenges in implementing climate change mitigation strategies. Forests, 9(12), 742
Droh G., Djezou K.M., Kouassi K.B.A., Kouassi A.B. and Tiecoura K. (2022) Diversity of Arbuscular Mycorrhizal Fungi Spores in Maize (Zea mays L.) Plantations in Côte d'Ivoire. American Journal of Agriculture and Forestry. 10(5), 170-180.
Gerdemann J.W. and Nicolson T.H. (1963), Spores of mycorrhizal Endogone species extracted from soil by wet sieving and decanting. Transactions of the British Mycological Society, 46(2), 235-244
Leye E. H. M., Ndiaye M., Diouf M., Diop T. (2015). Etude comparative de l’effet de souches de champignons mycorhiziens arbusculaires sur la croissance et la nutrition minérale du sésame cultivé au Sénégal. African Crop Science Journal, 23(3), 211-219.
Pontes J.S., Oehl F., Pereira C.D., Machado C.T.T., Coyne D., Silva D.K.A., Maia L.C. (2024). Heterogeneity in Arbuscular Mycorrhizal Fungi and Plant Communities of the Brazilian Cerrado, Transitional Areas toward the Caatinga, and the Atlantic Forest. Microbial Ecology 87:29

Speaker: Mr Kouadio Meliton Djezou (UFR Biosciences, Laboratory of Biotechnology, Agriculture and Valorization of Biological Resources, Université Félix Houphouet‐Boigny, Abidjan, Côte d'ivoire)

145 Evaluating homemade dry manure tea as an alternative to synthetic fertilizers in spinach cultivation

Introduction

In the current agricultural landscape, the intensive use of synthetic fertilizers to meet the nutritional needs of crops, such as spinach, presents significant environmental and economic challenges. Historically, various cultures, especially in North African countries, have turned to organic methods like homemade manure tea (HMT) (Azeez et al., 2014). This tea, obtained by infusing manure in water, is known to facilitate the decomposition of organic matter and enhance nutrient release (Leauthaud et al., 2022). Although anecdotal accounts praise the benefits of HMT in terms of plant growth and soil quality improvement, there remains a lack of empirical studies validating these claims.
The quantity and quality of nutrients provided by these teas are not well-documented (Eudoxie and Martin, 2019).
Given these gaps, this study aimed to assess the impact of HMT on spinach biomass and leaf metrics in comparison to a synthetic fertilizer with equivalent concentrations of nitrogen (N), phosphorus (P), and potassium (K). Spinach (Spinacia oleraceae L.) was chosen due to its rapid growth rate, high nitrogen demand for optimal development, and its significant agronomic and nutritional importance (Pandjaitan et al., 2012; El-Saady, 2016).

Materials and Methods

The study focused on preparing Homemade Dry Manure Tea (HMT) using a popular North African technique before cultivating Lazio spinach in soil from Cazevieille, France, employing a completely randomized experimental design with five distinct treatments. Treatments T1 and T2 varied HMT dosages, with T1 being a lower typical dose and T2 six times the NPK content of T1. Three control treatments were also established: W (water only), S1, and S2, involving synthetic fertilizers designed to match the nutrient concentrations of HMT doses. The spinach was grown under controlled conditions for 41 days before harvest. Measurements included leaf count and dimensions, stem and petiole lengths, and both fresh and dry biomass weights. Chemical analysis of the aerial parts was conducted to assess nutrient content.

Results and Discussion

In our study examining the impact of homemade dry manure tea on the growth, morphology, and nutrient uptake of spinach, we observed that the use of a peasant dose of HMT resulted in a dry biomass comparable to that of a synthetic fertilizer with the same NPK concentration. This finding suggests that HMT, when used in modest amounts, could emerge as a viable alternative to synthetic fertilizers. Plants treated with T1 and S1 dosages displayed leaves noticeably longer and broader than those in the W control group. However, the plant roots did not exhibit significant variations in dry biomass between the different treatments.
Our analysis also disclosed heightened potassium absorption in plants subjected to the T1 and S1 treatments, compared to the W control group. This revelation is in line with previous studies highlighting the positive influence of increased potassium intake on the growth and yield of various plants.
Nonetheless, observations related to the T2 treatment raised concerns. Indeed, plants exposed to this treatment showed a significant decline in dry biomass, morphological measurements, and nutrient uptake. This trend suggests that high doses of HMT might contain components toxic to spinach. Moreover, the high salinity in HMT could play a pivotal role in the observed toxicity in the T2 treatment. It is also conceivable that other factors, such as micronutrient imbalances, or even microbial effects, are influencing these outcomes.

References
Azeez JO, Ibijola TO, Adetunji MT, Adebisi MA and Oyekanmi AA (2014) Chemical characterization and stability of poultry manure tea and its influence on phosphorus sorption indices of tropical soils. Communications in Soil Science and Plant Analysis 45, 2680–2696.
El-Saady WA (2016). Spinach (Spinacia oleracea L.) growth, yield and quality response to the application of mineral NPK fertilizer ratios and levels. Middle East J, 5(4), 908-917.
Eudoxie G and Martin M (2019). Compost tea quality and fertility. Organic fertilizers-history, production and applications.
Leauthaud C, Ameur F, Richa A, Ben Yahmed J, Tadjer N, Bakouchi S, Akakpo K, Djezzar M and Amichi H (2022). Production and use of homemade dry manure-based tea in fertigation systems in North Africa. Renewable Agriculture and Food Systems 37, 248–256.
Pandjaitan, N, Howard LR, Morelock, T, and Gil MI (2005). Antioxidant capacity and phenolic content of spinach as affected by genetics and maturation. Journal of Agricultural and Food Chemistry, 53(22), 8618-8623.

Speaker: Hana Lamouchi (UMR G-EAU, UMR Eco&Sols, CIRAD, Institut Agro, University of Montpellier, 2 Place Pierre Viala, 34060 Montpellier, France)

Agro-ecological transitions at the landscape and territorial levels (assessments)

Conveners: Souhil Harchaoui, Arnaud Delbaere

146 DMPP and DMPSA nitrification inhibitors’ effect on soil microbial communities in a grassland crop under two soil pH conditions

INTRODUCTION. Nitrogen (N) fertilization in agroecosystems can lead to non-desirable environmental impacts such as water pollution by nitrate leaching and the emission to the atmosphere of the greenhouse gas nitrous oxide. The application of nitrification inhibitors (NIs) such as dimethylpyrazole phosphate (DMPP) and dimethylpyrazole succinic acid (DMPSA) has been proven to be an efficient management option to avoid N2O losses when applied together with an ammonium-based fertilizer (Huérfano et al., 2018). Both DMPP and DMPSA have shown that they can induce some changes in non-target microbial populations different from nitrifiers in a single crop-cycle (Corrochano-Monsalve et al., 2021). Nitrification is a process known to be greatly inhibited by low pH conditions, thus the performance of NIs regarding both their effect on nitrifiers and on non-target microbial populations may not be the same depending on soil pH level. On the other hand, liming is a usual management in agricultural soils. Consequently, the objective of this work was to determine by means of a metabarcoding approach the performance of both NIs on soil microbial diversity under a slightly acidic pH condition in comparison with a neutral pH one.

MATERIALS, METHODS. A three-year experiment with Italian ryegrass (L. multiflorum Lam. var. Trinova) crop was carried out in Zamudio (Northern Spain) where two different pH level conditions of 5.5 (“low pH”) and 7.0 (“high pH”) were maintained, adjusting the pH by means of calcined dolomite application. Within each pH level condition, three fertilizer treatments were assayed: ammonium sulphate (AS), AS+DMPP and AS+DMPSA. NIs were applied at a rate of 0.8% of the ammonium-N of AS. Each year, ryegrass was sown and then cut and fertilized three times, a total amount of 600 kg N ha-1 were applied. At the end of the experiment soil samples were taken and soil microbial diversity was analyzed through bacterial 16S rRNA and fungal ITS massive amplicon sequencing using lllumina technology. Sequence quality control, taxonomical and diversity analyses were conducted using QIIME2 2023.9.

RESULTS. Alpha-diversity analysis showed that soil pH did not alter soil microbiota richness, while under low pH, AS application induced a decrease in their relative abundance, this decrease not being observed when NIs were applied. On the other hand, beta-diversity analysis signaled that neither pH nor the application of AS had any impact on the variations detected among treatments, while the application of NIs was responsible for 30% of the variation of the bacterial composition and 13% in the fungal composition of soils (p<0.05).

DISCUSSION. Most studies showing an effect of pH on soil microbiota have stablished comparisons of wide pH-ranges, between either different soils or same soils for an amount of time from twenty to a hundred years (Zhalnina et al., 2015). So, probably pH may have a more evident pivotal effect on microbial diversity when either long-term treatments or a wider range of pH to the one we have assayed are considered. Regarding the impact of NIs, provided that their target microorganisms are ammonia oxidizing bacteria, our results on beta diversity are of special interest because they indicate that DMPP and DMPSA can affect non-target microorganisms, both bacteria and fungi. This points to the need of future investigations on this topic.

REFERENCES.
Corrochano-Monsalve, M., González-Murua, C., Estavillo, J.M, Estonba, A., Zarraonaindia, I. 2021. Impact of dimethylpyrazole-based nitrification inhibitors on soil-borne bacteria. Science of The Total Environment 792: 148374
Huérfano, X., Estavillo, J.M., Fuertes-Mendizábal, T., Torralbo, F., González-Murua, C., Menéndez, S. 2018. DMPSA and DMPP equally reduce N2O emissions from a maize-ryegrass forage rotation under Atlantic climate conditions. Atmospheric Environment 187:255-265
Zhalnina, K., Dias, R., de Quadros, P.D., Davis-Richardson, A., Camargo, F.A., Clark, I.M., McGrath, S.P., Hirsch, P.R., Triplett, EW. 2015. Soil pH determines microbial diversity and composition in the park grass experiment. Microbial Ecology 69:395-406

ACKNOWLEDGEMENTS.
Spanish Government (Grant PID2021-128273OB-I00 funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”), Basque Government (IT1560-22) and EuroChem Agro Iberia S.L M.M. is holder of an IKERTALENT2022 Fellowship funded by the Basque Government and M.J.M. is holder of the contract PRE2022-102053 funded by MCIN/AEI/10.13039/501100011033 and FSE+. Z.S.S. received a grant co-financed by the European NextGenerationEU.

Speaker: Maitane Juárez-Mugarza (Universidad del País Vasco UPV-EHU)

147 Spatio-temporal microbial regulation of aggregate-associated priming effects under contrasting tillage practices

[Introduction] Soil organic carbon (SOC) sequestration is essential for sustaining soil health and food supply in agroecosystems (Turmel et al., 2015). The amount of organic C stored in soil reflects a net balance between C inputs and outputs (Kuzyakov and Domanski, 2000). Soil is a complex matrix with a spatially heterogeneous distribution of SOM at different spatial scales (Schlüter et al., 2022). Soil aggregate-size classes govern microbial accessibility, nutrient status of habitats, and SOC recalcitrance (Trivedi et al., 2017). Tillage intensity significantly influences The heterogeneous distribution and dynamic changes of soil microorganisms, consequently shaping spatio-temporal patterns of SOC decomposition. However, little is known about the microbial mechanisms by which tillage intensity regulates the priming effect (PE) dynamics in heterogeneous spatial environments such as aggregates. [Materials, methods] Herein, a microcosm experiment was established by adding 13C-labeled straw residue to three distinct aggregate-size classes (i.e., mega-, macro-, and micro-aggregates) from two long-term contrasting tillage histories (no-till [NT] and conventional plow tillage [CT]) for 160 days to observe the spatio-temporal variations in PE. Metagenomic sequencing and Fourier transform mid-infrared techniques were used to assess the relative importance of C-degrading functional genes, microbial community succession, and SOC chemical composition in the aggregate-associated PE dynamics during straw decomposition. [Results and Discussion] Spatially, straw addition induced a positive PE for all aggregates, with stronger PE occurring in larger aggregates, especially in CT soil compared to NT soil. Larger aggregates have more unique microbial communities enriched in genes for simple C degradation (e.g., E5.1.3.6, E2.4.1.7, pmm-pgm, and KduD in Nitrosospeera and Burkholderia), contributing to the higher short-term PE; however, CT soils harbored more genes for complex C degradation (e.g., TSTA3, fcl, pmm-pgm, and K06871 in Gammaproteobacteria and Phycicoccus), supporting a stronger long-term PE. Temporally, soil aggregates played a significant role in the early-stage PEs (i.e., < 59 days after residue addition) through co-metabolism and nitrogen (N) mining, as evidenced by the increased microbial biomass C and dissolved organic C (DOC) and reduced inorganic N with increasing aggregate-size class. At a later stage, however, the legacy effect of tillage histories controlled the PEs via microbial stoichiometry decomposition, as suggested by the higher DOC-to-inorganic N and DOC-to-available P stoichiometries in CT than NT. Our study underscores the importance of incorporating both spatial and temporal microbial dynamics for a comprehensive understanding of the mechanisms underlying SOC priming, especially in the context of long-term contrasting tillage practices.

Speaker: Yeye Zhang (Northwest Agriculture & Forestry University)

148 Does no-till cover crop termination improve soil health in the short-term?

In intensive vegetable production systems, cover crops are usually incorporated into the soil by disking prior to the subsequent crop. In recent years, silage tarps have gained popularity amongst farmers in Quebec as a suitable tool for no-till cropping systems. Termination of cover crops by roller-crimping is another strategy used by organic farmers. However, these practices have not been studied extensively in vegetable cropping systems in Eastern Canada. Our main objective was to assess the impact of cover crop termination with or without tillage on soil health indicators.
A 2-year field experiment (2022-2023) was conducted on a clay loam at a research site in Saint-Augustin-de-Desmaures, QC, Canada. An annual spring-seeded cover crop mixture was terminated in mid-July, followed by a vegetable crop in both years. In 2022, a mixture of field peas and oats was seeded, while in 2023, the cover crop mixture consisted of field peas and faba beans. Treatments were arranged in a split-plot design with four blocks. Cover crop termination methods were ascribed to main plots. They consisted of 1) roller-crimping, 2) flail-mowing and tarping, 3) flail-mowing and incorporation by disking, and 4) a fallow control with no-cover crop. The subplot factor was the fertilization rate of vegetable crops based on provincial nitrogen recommendations (0%, 50%, and 100%). After the termination of cover crops, broccoli and beetroot were transplanted in 2022 and 2023, respectively. At harvest time, soil samples were collected at a 0-10 cm depth, and soil health indicators were measured using soil-based lab tests.
The use of spring cover crops resulted in a higher proportion of water-stable aggregates (>2mm) and a larger mean-weight diameter of stable aggregates compared to the no-cover crop control. Soil respiration values were higher in the treatments with cover crop than in the no-cover crop control, and soil bulk density was higher in the roller-crimped cover crop treatment than in the other treatments. Broccoli and beetroot yields were lower in the roller-crimped treatment compared to the other treatments. Surprisingly, yields were similar between the no-cover crop control and cover crops incorporated by disking. Nonetheless, our results showed that establishing spring-seeded cover crops into organic vegetable production systems offers some soil health benefits in the short-term.

Speaker: Michaël Brière (Université Laval-Département de phytologie)

149 Influence of organic farming on microorganisms associated to crop plants – from landscape to local scale

Introduction
Intensive agriculture has been promoted since the green revolution in the 1960s to boost crop yields and satisfy increasing food demand (Mann, 1999). Such intensification led to modifications in agricultural practices with higher fertilization, increased pest control and intense varietal selection among others. Additionally, the increase in the overall agricultural land cover led to marked changes in land use at the expense of natural and semi-natural habitats (Tscharntke et al., 2005). Because of these changes occurring at local and landscape scales, agricultural intensification strongly shaped ecosystem properties (Matson et al., 1997) and resulted in an important loss of biodiversity in many taxonomic groups (e.g. Hole et al., 2005; Gonthier et al., 2014). Despite the key role of symbiotic microorganisms in plant nutrition and protection, the impact of agricultural intensification on these microorganisms is not fully understood. Organic farming, which has been proposed as an alternative farming system, aimed at promoting more efficient soil natural ecosystem services (e.g. organic matter cycling, storage, redistribution of mineral nutrient…), should be favorable for microorganisms. It may promote a higher microbial diversity thanks to lower anthropic disturbance and higher plant diversity. It is also expected to strongly affect species composition and result in changes in plant growth and health.

Materials, Methods
We sampled plants in pairs of winter wheat fields (one organic and one conventional) along a distance gradient to the edges (hedgerow versus grassy), in 20 landscape windows selected along an uncorrelated gradient of organic farming and hedgerow density. Firstly, we analyzed the relative effect of organic farming and field edge types on endophytic microbial assemblages associated with wheat plants. Secondly, we tested the effect of the farming practices characterizing farming systems on endophytic microbial assemblages associated with wheat plants, and related these changes with wheat performance in the field. To achieve these goals, we collected environmental data through farmer interviews, soil analyses, and plant inventories. We also analyzed root microbiota through next-generation sequencing at vegetative and flowering stages.

Results
We demonstrated that organic farming shaped microbial composition and increased fungal and bacterial richness in most phyla. In contrast to bacteria, fungal communities were heterogeneously distributed within fields, having a higher diversity for some phyla close to field edges. Fungi responded more strongly to the field scale while bacteria were more affected by landscape scale. Effect of organic farming at the field level was mostly due to soil characteristics and field management, and a little to plant diversity in the field. Microbial responses were more pronounced at the late developmental stage, likely as a result of accumulative effect of management actions during plant development. Seed production and resistance to pathogens were related to specific phyla that are important for seed production and/or wheat resistance to septoriose.

Discussion and conclusion
The present study provided a better understanding of the effect of organic farming and of its scale of influence on plant-associated microbiota. We showed the positivet effect of organic agriculture at both field and landscape scales on wheat endophytic richness providing evidence that agricultural management needs to be considered at several spatial scales. More especially, we demonstrated that increasing the percentage of organic agriculture at the landscape scale can maintain higher bacterial richness even in conventional fields. We stressed also the importance of soil characteristics and management in shaping microbiota composition and diversity. Plant seed production and resistance to pathogens were related with particular microbes, such as Alphaproteobacteria and Glomeromycota. This work advances our understanding of how farming system, and particular agricultural practices affect plant microbiota, and plant performance through microorganism-mediated changes. It supports the use of microorganisms as pillars of sustainable crop production.

References
Gonthier DJ et al., 2014. Biodiversity conservation in agriculture requires a multi-scale approach. Proc R Soc B., 281:1358
Hole DG et al., 2005. Does organic farming benefit biodiversity? Biological Conservation, 122:113-130.
Mann C., 1999. Crop scientists seek a new revolution. Science, 310-314.
Matson, PA et al. 1997. Agricultural intensification and ecosystem properties. Science, 277:504-509.
McLaughlin A, Mineau P, 1995. The impact of agricultural practices on biodiversity. Agri Ecosyst Environ., 55:201-212.
Tscharntke T, Klein AM, Kruess A, et al. 2005. Landscape perspectives on agricultural intensification and biodiversity – ecosystem service management. Ecology letters, 8:857-874.

Speaker: cendrine mony (université de Rennes)

255_cmony.pptx

150 Availability and nutritional contribution of organic waste products in agriculture, using Sweden as a case study

(1) Modern food production largely rely on a linear nutrient flow, with nutrients entering the field as bought fertilisers, or potentially as farmyard manure, but with little return of nutrients from the society. Returning organic waste products is a way of closing nutrient cycles between agriculture and society, contributing to a circular economy where resources are reused (Rosemarin et al., 2020), and maintain or increase soil organic matter content compared to using mineral fertilisers (Kätterer et al., 2011). Moreover, in organic farming, crop nutrition largely depends on manure, and low manure accessibility has been argued to contribute to the low adaption to organic farming in regions where crop production is dominating (Nordin, 2021). The aim of this study was to assess the current availability of the organic waste products biogas digestate, mainly produced from food waste and farmyard manure, sewage sludge (although currently not allowed in organic farming), and other organic nutrient sources. Furthermore, we aimed at comparing the nutrient of these materials to crop nutrient demands of today as well as a future scenario with more land cultivated with organic farming management methods, using Sweden as a case study.
(2) Crop production conditions vary greatly in Sweden, a country that stretch from 55°N to 69°N. It has fertile plains in the south, but also much land that is difficult to cultivate with annual crops and where forestry and animal husbandry dominate. The change in latitude also cause differences in cropping season characteristics. To account for this Sweden is divided into eight production areas and the study uses these production areas when estimating crop nutrient demand and availability. Data on land cultivated with different crops and their yields, and production and nutrient content of biogas digestate, manure, sewage sludge and other waste product-based fertilisers produced in Sweden have been obtained from national statistics and from communication with biogas digestate facilities, a sewage sludge certification body and the Swedish Environmental Protection Agency.
(3) The availability of organic waste products from society (biogas digestate and sewage sludge) suitable for use in agriculture, and their potential to cover regional crop nutrient demand, vary between production areas, with higher availability in areas with much crop production and a larger population size, i.e. the southern part of the country. The availability of farmyard manure is unsurprisingly lower in areas with a large proportion of specialised crop production farms. The nutritional quality of biogas digestate compared to farmyard manure is similar for total nitrogen, on average somewhat higher for mineral nitrogen concentrations (kg/t wet weight), and lower for phosphorous and potassium concentrations. Total nitrogen and phosphorous concentration of sewage sludge is substantially higher than those both in biogas digestate and farmyard manure, linked to higher dry matter content. The data are currently being evaluated, scenarios defined and nutrient demands for these different scenarios calculated.
(4) Although biogas digestion of manure can increase its nutritional value (Cavalli et al., 2016) low nutrient concentrations per wet weight and bulkiness of these products are disadvantages, as well as for sewage sludge. There are methods to be used to dehydrate these products or extract the nutrients from the solid or liquid phase and hence increase their fertiliser value (Monfet et al., 2018). However, this comes at a cost of reduced contribution to soil organic matter and soil fertility. Therefore, these methods are more interesting in areas where there is less crop production and hence longer distances to arable fields and these products could instead be sold to regions with more production.

References
Cavalli et al. (2016). Nitrogen fertilizer replacement value of undigestated liquid cattle manure and digestates. European Journal of Agronomy, 73, 34-41.
Kätterer et al. (2011). Roots contribute more to refractory soil organic matter than aboveground crop residues, as revealed by a long-term field experiment. Agriculture Ecosystems and Environment, 141(1-2), 184-192.
Monfet et al. (2018). Nutrient removal and recovery from digestate: a review of the technology. Biofuels, 9(2), 247-262.
Nordin (2021). Is a shortage of manure a constraint to organic farming? Working paper 2021:1. AgriFood Economics Center. Lund, Sweden.
Rosemarin et al. (2020) Circular nutrient solutions for agriculture and wastewater – a review of technologies and practices. Current Opinion in Environmental Sustainability, 45, 78–91.

Speaker: Elsa Lagerquist (Swedish University of Agricultural Sciences)

Climate change adaptation and mitigation

Conveners: Alessandra Virili, Moltine Prebibaj

151 What opportunities exist for climate change mitigation in agriculture? A land-based emissions and mitigation measures analysis

The growing negative impacts of climate change on society and ecosystems necessitate accelerating the transition towards sustainable mitigation solutions. Agriculture is responsible for around 12% of EU greenhouse gas (GHG) emissions (EEA, 2022). Yet, it also offers significant opportunities for climate change mitigation, notably through the potential of agricultural soils to sequester carbon. However, addressing GHG emissions in agriculture requires the disposition of reliable tools for decision-making and the implementation of measures specifically tailored to the territories (Borghino et al., 2021). This study focuses on the Mediterranean island of Sardinia in Italy, which covers almost 24,000 km2, roughly half of which is used for agriculture. Further attention in this study is given to the Tirso River basin due to its regional significance and representation of Sardinia’s diverse agricultural activities, ranging from intensive animal and crop production to marginal, heterogeneous, and semi-extensive production systems, including agroforestry and sheep farming. We present a “cradle-to-gate” life cycle analysis (LCA) applied to the region of Sardinia to i) estimate agricultural GHG emissions, ii) pinpoint the most contributing sectors and sub-regions, and eventually iii) develop mitigation scenarios and evaluate their potential opportunities within the island’s agricultural context. Estimates of GHG emissions and mitigation potentials are based on the Tier 1 and Tier 2 methods of the Intergovernmental Panel on Climate Change (IPCC) guidelines for national greenhouse gas inventories. The region’s significant dedication to animal sector activities, particularly sheep husbandry, despite its semi-extensive nature, along with intensive cattle breeding in the central and western part, makes it a hotspot for GHG emissions. Most crop production sector emissions result from agricultural machinery and fertilizer use, with intensity varying based on land use characteristics. Measures to improve the environmental performance of the region’s agricultural sector are explored, encompassing GHG emissions reduction, avoidance, and carbon stock enhancement in soil and biomass. Among the scenarios analyzed, opportunities emerge from applying sustainable land-based mitigation options such as reduced tillage, organic farming expansion, and agroforestry implementation.

References:
EEA-European Environment Agency, 2022. Annual European Union greenhouse gas inventory 1990-2020 and inventory report 2022.
Borghino, Noélie, Michael Corson, Laure Nitschelm, Aurélie Wilfart, Julie Fleuet, Marc Moraine, Tor Arvid Breland, Philippe Lescoat, and Olivier Godinot, 2021. Contribution of LCA to decision making: A scenario analysis in territorial agricultural production systems. Journal of Environmental Management 287, 112288.

Speaker: Lara Abou Chehade (CMCC Foundation - Euro-Mediterranean Center on Climate Change, Italy)

152 Farm resilience in Mediterranean agricultural territories: a multi-scale and multi-risk approach in France and Tunisia

The Mediterranean region is considered a hot spot for climate change with recent acceleration generating major risks in several key sectors, particularly concerning water availability or food production (Cramer et al., 2018). The resilience of agriculture has recently become a critical challenge in supporting farmers in a context of increasing short- and long-term risks. Over the past decade, multiple authors have published resilience frameworks (Meuwissen et al., 2019; Perrin and Martin, 2021). In their review, van der Lee et al. (2022) highlighted complementarities between these frameworks, particularly between agroecological and resilience capacities approaches. While agroecological approaches focus on practices with few links with perturbations and capacities, the capacities approaches often inadequately consider farmer’s practices. Another gap identified by Darnhofer et al. (2016) is the lack of attention paid to relations - between physical entities (e.g., flows of nutrients) and social groups (e.g., power, learning) - in understanding resilience of farming systems.
This study aims to develop an operational framework for assessing the resilience of farming systems, considering both farmer’s adaptation strategies in response to perceived risks and the central role of the relations between farms, farmers and their environment (nutrient cycling, advice services, resource sharing, etc.), which contributes to their resilience capacities in facing both short- and long-term risks. We apply this framework to two contrasted areas in the Northern and Southern Mediterranean basin.

We assembled a multi-disciplinary research team (agronomy, economy, geography) to develop and operationalize the concept of relational resilience at farm scale. We conduct tests in two areas located in France (Aude valley), and Tunisia (Siliana). In each region, we conduct semi-directed interviews with different types of farmers and with other stakeholders including public institutions, input suppliers or advice services. The objectives of the farmer interviews are threefold. Firstly, we gather their perceptions of climatic risks among other risks, considering the relative importance given to both short-term (e.g., drought, price inflation) and long-term risks (e.g., disappearing resource). Secondly, we document the adaptation strategies they are implementing or planning to implement. Each strategy is detailed as a set of technical and organizational practices aimed at facing one or several perturbations. Thirdly, using practices as a starting point, we identify the resources (individual or collective) and the capacities that farmers mobilized or lacked, in order to adapt. We focus on the relationships linking actors and the elements of the system, considering them as important components for building resilience. Interviews with other stakeholders aim to identify their facilitating or hindering role for each kind of adaptation strategies.

Our framework is structured around four components (Fig. 1). Firstly, the risks that are perceived by the stakeholders include different categories of climate risks (e.g., drought, flood, temperature rising) as well as sanitary, market or political risks. Secondly, the resources mobilized are categorized according to the livelihood literature, encompassing biophysical, social and cognitive resources. Thirdly, we specifically examine inter-individual relations: with whom farmers develop adaptations, if they mobilize collective resources, i.e. what are the coordination or flows required for adaptation. Finally, resilience outcomes are described based on the evolution of the system during the adaptation process (stability, adjustment or transformation).

Our (ongoing) results show different configurations of adaptation strategies based on local factors (such as resources, climatic shocks) and regional contexts (France, Tunisia). These strategies exhibit a gradient of dependence on both physical and relational resources, which may be used to face short- and long-term risks.

The diversity of adaptation strategies among stakeholders leads us to consider the interactions occurring between actors to mobilize resources, especially for those identified as critical. The next step would be to analyze the property of the social-ecological networks that support resilience (Labeyrie et al., 2024). Such research could aid in proposing frameworks for public policies and support for agriculture in the face of increasing multifaceted risks.

References

Cramer et al., 2018. Nat Clim Change 8, 972–980.
Darnhofer et al. 2016. J Rural Stud 44, 111–122.
Labeyrie et al., 2024. Ag Sys 215, 103832.
Meuwissen et al., 2019. Ag Sys 176, 102656.
Perrin, A., Martin, G., 2021. Ag Sys 190, 103082.
van der Lee et al., 2022. Agron. Sustain. Dev. 42, 1–20.

Speaker: Laure Hossard (Innovation, Univ Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France)

VIAMED_ESA2024_VF.pdf

153 Syppre: innovative systems to meet the challenges of improving agriculture's carbon balance.

In the context of climate change, the reduction of greenhouse gases (GHG) emissions and the storage of carbon in soil must be encouraged to limit global warming. The agricultural sector contributes to 18.4 % of French GHG emissions in which 29 % was associated with crop fertilization (Citepa, 2023). Field crops are part of the problem through the use of fertilizers, as well as to the loss of soil carbon through the important export of biomass non compensated by return of organic matter to the soil. However, technical solutions do exist to improve the carbon balance of field crop farming systems such as cover crop, use of organic fertilisers or reduced use of mineral fertilizers (Pellerin et al. 2019).
These technical solutions are mobilized in the innovative systems of the Syppre project in which three French technical institutes on arable crops collaborate (ARVALIS Institut du végétal, Terres Inovia and Institut Technique de la Betterave). This project aims to support the development of innovative arable cropping systems reconciling productivity, economic profitability and environmental protection (Toqué et al. 2015). The innovative systems have been tested since 2017 in five French regions specialised in arable crop production: the deap loamy soils of Picardy, the chalk soils of Champagne, the shallow clay-limestone soils of Berry, the clay-limestone hillsides of Lauragais and the humus-rich soils of Béarn. On each site, an innovative system co-designed with regional agricultural stakeholders has been tested in field conditions, and compared to a reference system, which is representative of current systems observed in the region. To meet Syppre's objectives and local issues, the innovative cropping systems mobilize agroecological solutions using a systemic approach, such as crop diversification, modification of soil tillage, introduction of cover crops, cultivar diversity, and biocontrol products. Cropping systems performances were evaluated every year, and different indicators of soil fertility were measured. The carbon and nitrogen stocks were in particular measured at the beginning of the trial and used to simulate the evolution of soil organic status. The carbon balances of cropping systems were calculated with the French Label Bas Carbone methodology.
After 7 years of trials, we observed a great reduction of nitrogen fertilizer use (between -10% and -46%) and GHG emissions (between 0.33 and 0.7 teqCO2 per year and per hectare) for all the innovative systems compared to the references. Even if all innovative systems do not have a positive effect on carbon storage, all systems have a positive carbon balance. But the economic performances decreased for almost all of them. The presentation will detail the levers used to reduce mineral nitrogen fertilizer amount and improve soil fertility, the effect already visible, and the expected ones in long term scale, the consequences on crop and system performances as well as the effect on carbon balance. It will also discuss the perspectives of interesting solutions to consider in the future, technical or economic.

CITEPA, 2023. Gaz à effet de serre et polluants atmosphériques. Bilan des émissions en France de 1990 à 2022. Rapport Secten éd. 2023.

TOQUE C, CADOUX S, PIERSON, P, DUVAL R, TOUPET A-L, FLENET F, CARROUE B, ANGEVIN F, GATE P. 2015. SYPPRE : A project to promote innovations in arable crop production mobilizing farmers and stakeholders and including co-design, ex-ante evaluation and experimentation of multi-service farming systems matching with regional challenges. 5th International Symposium for Farming Systems Design

PELLERIN et al, 2019. Stocker du carbone dans les sols français, Quel potentiel au regard de l’objectif 4 pour 1000 et à quel coût ? Synthèse du rapport d'étude, INRA (France), 114 p.

Speaker: Marie Estienne (Arvalis)

#172_Estienne.pdf

154 On-farm assessment of warming impact on winter cereals under different N fertilisation strategies: a Mediterranean case study

Winter cereals play a crucial role in human diets. The initial impacts of climate change on these strategic crops include yield stagnation and increased yield variability (Olesen et al., 2011). Projections indicate that for every additional degree Celsius of temperature increase, global wheat production could decrease by 6% (Asseng et al., 2015). Climate change impacts and adaptation strategies vary regionally due to interactions with soil, existing climate conditions, and agricultural practices (Olesen et al., 2011). Effective management practices can compensate the effects of climate variability, emphasizing the need for region-specific studies to identify suitable adaptation strategies. In irrigated areas, compensating for reduced precipitation risk can be feasible, but addressing temperature rise presents significant challenges. This study aims to empirically evaluate the effectiveness of different N fertilisation strategies to adapt to warming on winter cereals in Mediterranean irrigated conditions.

An on-farm field experiment was established in the Ebro valley (Sucs, Lleida, Spain; 41°41'50.0"N 0°26'51.1"E) in a surface irrigated area, for 2 winter cropping seasons (2022-2023, 2023-2024) in the framework of the ECO-TRACE project. Winter hybrid wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) were cropped on the first and second cropping seasons, respectively, under two climate scenarios: current climate and warming. Passive open-top chambers (OTC) were used to simulate warming, adapted from the design of Welshofer et al., (2018). Six N fertilisation scenarios were also assessed: control (0N); business as usual (BAU), consisting of a pre-sowing fertilisation with pig slurry (220 kg N ha-1 yr-1) and top-dressed synthetic fertiliser (70 kg N ha-1 yr-1); full slurry (the sole application of pig slurry before sowing at same rate than BAU); full synthetic, including pre-sowing and top-dressing synthetic fertilisation (50 and 120 kg N ha-1 yr-1, respectively); and two treatments including a mixture of legumes (Medicago sativa L. and Trifolium repens), undersown in one treatment as living mulch and in the other as non-living mulch. Treatments were assessed using a split-plot design with 3 replications. Grain yield, its components, above-ground biomass, and their N concentration were measured at physiological maturity. Air (at 12.5 cm), soil (at 10 cm depth), and soil surface temperature were continuously monitored with sensors, along with soil volumetric moisture.

The 2022-2023 cropping season was dry from October until May (110 mm, 39% of the average), offset by 3 irrigation events of 100 mm each. During the reproductive phase, in April and May, mean temperatures exceeded the average by 5ºC, reaching above 28ºC for 7 days. Legumes couldn’t get satisfactorily established. Warming led to an increase of monthly air, soil surface and soil temperature of 1.5 and 2 and 2.4ºC compared to the current climate, respectively, and a decrease of soil volumetric moisture of 12%. Warming reduced grain yield and above-ground biomass production by 20% (6.2 vs. 7.6 t ha-1, 14% Hº, p=0.01) and 11%, respectively, compared to the current climate. This was related to yields components with i) less grains per spike (34.9 vs. 41.9, p<0.01), and ii) a lower TGW (39.7 vs. 43.9, p<0.01) under warming. TGW was also affected by the fertilisation scenarios, with lower values in BAU (35.5 g) compared to full synthetic (41.5 g) and 0N (43.9 g) (p<0.01). Warming increased grain and biomass N concentration due to dilution effect (2.21 vs. 1.96% for grain, and 1.37 vs. 1.14% for biomass, respectively) (p<0.01). As result, crops under warming climate, in both BAU and full synthetic scenarios, exhibit reduced uptake of grain N compared to current climate (p<0.01).

Fertilisation strategies failed to counteract the significant impacts of warming; instead, some resulted in reduced grain N uptake, indicating lower resilience. Further validation of these preliminary findings will be presented based on the results of the on-going 2023-2024 cropping season.

References
Asseng, S., F. Ewert, P. Martre, R.P. Rötter, D.B. Lobell, et al. 2015. Rising temperatures reduce global wheat production. Nat. Clim. Chang. 5(2): 143–147. doi: 10.1038/nclimate2470.
Olesen, J.E., M. Trnka, K.C. Kersebaum, A.O. Skjelvåg, B. Seguin, et al. 2011. Impacts and adaptation of European crop production systems to climate change. Eur. J. Agron. 34(2): 96–112. doi: 10.1016/j.eja.2010.11.003.
Welshofer, K.B., P.L. Zarnetske, N.K. Lany, and L.A.E. Thompson. 2018. Open-top chambers for temperature manipulation in taller-stature plant communities. Methods Ecol. Evol. 9(2): 254–259. doi: 10.1111/2041-210X.12863.

Speaker: Ms Louise Blanc (Department of Agricultural and Forest Sciences and Engineering - Agrotecnio-CERCA Center, Universitat de Lleida, Av. Rovira Roure 191, 25198 Lleida, Spain.)

155 Site conditions determine heat and drought induced yield losses in wheat and rye in Germany

Increasing and heat and drought are major abiotic stressors threatening European cereal yields under climate change. So far little is known about the spatio-temporal yield effect of these stressors (Lüttger and Feike, 2018). In this study, we assess genotype (G) × environment (E) × management (M) specific weather-yield relations utilizing spatially explicit weather indices (WIs) and variety trial yield data of winter wheat (Triticum aestivum) and winter rye (Secale cereale) for all German cereal growing regions and the period 1993–2021. The objectives of this study are to determine the explanatory power of different heat and drought WIs in wheat and rye, to quantify their site-specific yield effects, and to examine the development of stress tolerance from old to new varieties. We use mixed linear models with G × E × M specific covariates as fixed and random factors. We find for both crops that combined heat and drought WIs have the strongest explanatory power during the reproductive phase. Furthermore, our results strongly emphasize the importance of site conditions regarding climate resilience, where poor sites reveal two to three times higher yield losses than sites with high soil quality and high annual precipitation in both crops. Under good site-conditions heat and drought stress hardly cause any significant yield losses. Finally, our analysis reveals significantly higher stress-induced absolute yield losses in modern vs. older varieties for both crops, while relative losses also significantly increased in wheat but did not change in rye. Our findings highlight the importance of site conditions and the value of high-yielding locations for global food security. They further underscore the need to integrate site-specific considerations more effectively into agricultural strategies and breeding programs.

References
Lüttger, A.B. and Feike, T. (2018) Development of heat and drought related extreme weather events and their effect on winter wheat yields in Germany Theor. Appl. Climatol. 132 15–29

Speaker: Til Feike (Julius Kühn Institute, Federal Research Centre for Cultivated Plants, Institute for Strategies and Technology Assessment, Kleinmachnow, Germany)

156 New resilient cropping systems for Europe

Introduction
Agriculture is currently facing the challenge of ensuring food security. In addition, climate change affects the sustainability of farming systems by decreasing crop yield and soil fertility (Kakabouky, 2021). Novel agriculture practices, such as the inclusion of alternative crops into traditional cropping systems could be a new solution to pursue environmental benefits. In recent years, there has been growing interest in two easy-to-grow oilseed crops belonging to the Brassicaceae family: Camelina sativa (L. Crantz) and Brassica carinata (A. Braun). Camelina is a low agronomic input crop which can adapt to different environments and produce oil suitable for multiple bio-based application (Zanetti et al., 2021). Carinata is a resilient crop with high erucic acid contents, thus suited to produce biofuels, including aviation fuels (Seepaul et al., 2021). The present study was carried out to support the development of these two crops within conventional EU cropping systems, and to provide insights on the use of camelina and carinata oil.

Materials and methods
Camelina and carinata were tested in a multi-location trial (Italy and Serbia) in different cropping systems for two consecutive growing season (2022-24). The trials were carried out at the experimental farm of the University of Bologna (Italy) and at the Institute of Field and Vegetable Crops at Rimski Šančevi, Novi Sad (Serbia). Three camelina varieties (CCE44 and CCE117 by Camelina Company, Spain, and Lenka by the University of Poznan, Poland) were evaluated in Italy, whereas two camelina varieties (NS Zlatka and NS Slatka) were investigated in Serbia. Each variety was sown in (strip plots of about 5000 m2) at the end of October. At both sites, sunflower and sorghum were double cropped after camelina (harvested in June) and compared with a common sole-crop system (food crops sown in April). Carinata (sown in autumn 2023) (Nujet350 by Nuseed, France) was intercropped with chickpeas in Italy and with barley in Serbia.

Results
During the first growing season, the meteorological conditions in both countries were in line with long-term data. A remarkable difference was recorded in Italy in May 2023 when almost 275 mm of rain caused a soil flooding. In Serbia, temperatures in winter months were higher than long-term data and May 2023 was marked by 131 mm of precipitation. Concerning the cash-cover cropping system, the productivity of camelina significantly changed depending on variety with variety CCE117 which reached the highest seed yield in Italy. In Serbia, the seed yield of camelina was on average 1.6 Mg ha.1. With regard to food crops after camelina, sunflower was successfully in both countries (1.8 and 2.6 t ha-1, in Italy and Serbia, respectively), whereas sorghum showed a too long growing cycle remaining green until November. The harvest of the second-year trial of camelina and the first-year trial of carinata cropping systems is planned in summer 2024.

Discussion
From these first results, camelina confirmed its resilience despite adverse weather conditions characterizing the first growing season and achieved seed yields in line with the literature in Serbia. Although no data are available yet on the carinata intercropping system, the crop seems to fit well combined with food crops in both Italy and Serbia regions. It is necessary to keep on searching for new solutions to diversify the structure of farming systems, integrate alternative crops that are adapted to climate change and mitigate water and nitrogen losses, reduce chemical input and C02 emissions.

References
Kakabouki I., Tataridas A., Mavroeidis A., Kousta A., Roussis I., Katsenios N., Efthimiadou A., Papastylianou P. (2021). Introduction of alternative crops in the Mediterranean to satisfy EU Green Deal goals. A review. Agronomy for Sustainable Development, 6: 41-71.
Seepaul, R., Kumar, S., Boote, K.J., Small, I.M., George, S. and Wright, D.L. (2021), Physiological analysis of growth and development of winter carinata (Brassica carinata A. Braun). GCB Bioenergy, 13: 1112-1133.
Zanetti, F., Alberghini, B., Marjanovi´c Jeromela, A., Grahovac, N., Rajkovi´c, D., Ki`erpvski, B., Monti, A., 2021. Camelina, an ancient oilseed crop actively contributing to the rural renaissance in Europe. A review. Agronomy Sustainable Development, 41, 2.

Speaker: Maria Giovanna Sessa (University of Bologna)

347_Sessa.pptx

Future & optimization

Conveners: Claas Nendel, Clara Lefèvre

157 Unveiling the short-term impacts of conservation agriculture: a two-year experiment in the Tuscany region, Italy

1. Introduction: In the Mediterranean context, conservation agriculture (CA) is gaining importance due to the rising costs of conventional agriculture (CN) (Cicek et al., 2023). Various solutions have been identified to mitigate the initial drawbacks of switching from CN to CA, but yield losses and soil compaction still occur. The aim of the experiment was to assess the short-term effects of switching from CN to CA. In particular, the effect of switching from conventional (CT) to reduced tillage (RT) with and without cover crop (CC) management was evaluated.
2. Materials and methods: The study was performed from October 2021 to February 2024 (2 growing seasons; GSs) at the Tereto Living Lab of the Tuscany region (Arezzo, Italy). The soil is characterized by a clay-loam texture (sand 23%, Silt 42%, and clay 35%), an alkaline pH (8.2), an initial bulk density of 1.32 t m-3, and a low content of organic matter (1.73%). The climate of the area is Mediterranean, with an average year temperature of 14°C and average annual rainfall of 742 mm. Before the start of the experiment, a two-crop rotation of a winter and a spring crop was applied for more than 5 years with conventional ploughing, leaving fallow for several months. After the start of the experiment, only chisel plough was passed over the RT plots. The experimental design was a completely randomized block design (3 blocks and 3 replications per block) with tillage as the main factor, and CC nested into tillage as split plot. A crop rotation of winter and spring cereals (winter wheat and spring barley, respectively) was applied. Tillage radish (TR; Raphanus sativus L. var. longipinnatus) was selected as CC between the two main crops compared to fallow management. The biomass and grain yield (GY) of the different crops were determined at maturity. Undisturbed soil samples were collected for bulk density (BD) measurement at the following soil depths: 0-5, 5-10, 10-20, and 20-30 cm.
3. Results: At the beginning of the trial, the average BD was about 1.34 (0.01) t m-3. BD values measured in RT after the 1st GS significantly increased at 0-5, 5-10, 10-20, and 20-30 cm by 3.84%, 7.33%, 4.11%, and 4.36%, respectively, while BD increased in CT by 1.94%, 1.01%, 0.15%, and 1.19%, respectively, compared to the initial values. With respect to the initial values, the average BD measured after the 2nd GS at 0-5, 5-10, 10-20, and 20-30 cm, increased by about 3.54%, 7.33%, 4.04%, and 4.36%, respectively in RT, while it increased by about 3.43%, 6.20%, 7.57%, and 4.33%, respectively, in CT.
   GY of winter wheat measured in TR was significantly lower than that measured in CT by about 21%, likewise, GY of spring barley in RT was significantly lower by 41% compared to that measured in CT. Furthermore, the CC biomass in RT measured in the 1st and 2nd GS was significantly lower by 69% and 73%, respectively, compared to that in CT. The GY of spring barley grown after the TR treatment was significantly higher by 21% in RT and by 11% in CT compared to that grown after fallow.
4. Discussion: The study confirms the initial disadvantages of switching from CN to CA, as the effect of RT on soil physical properties was detected just after the TR termination. RT determined a significant increase in BD, which negatively affected crop yield. Moreover, the integration of different CN practices led to a reduction in the yield gap. In particular, the sowing of TR in RT was effective in reducing the yield loss of spring barley. Similar results were reported by Landschoot et al.(2019), as they detected a mitigation of yield losses in a RT system by CC sowing. On the other hand, the beneficial effect of TR was limited by the reduction in biomass accumulation in RT with respect to CT.
5. References Cicek, H., et al. 2023. A critical assessment of conservation agriculture among smallholders in the Mediterranean region: adoption pathways inspired by agroecological principles. Agron. Sustain. Dev. 43. https://doi.org/10.1007/S13593-023-00926-4
   Landschoot, S., et al. 2019. Does shifting from conventional to zero tillage in combination with a cover crop offers opportunities for silage maize cultivation in Flanders? J. Plant Nutr. Soil Sci. https://doi.org/10.1002/JPLN.201900160

Speaker: Marco Napoli (Department of Agriculture, Food, Environment and Forestry (DAGRI) - University of Florence)

158 Subsurface Drip Irrigation and other water saving strategies to enhance plant production in a semiarid environment in Morocco

1. Introduction
The availability and quality of water resources impose substantial constraints on crop production, particularly affecting arid and semi-arid regions. In the Mediterranean, the climate change driven increase of irrigation requirements by 2080 is estimated to exceed 70 % when taking population growth into consideration [1]. The development and implementation of improved irrigation technologies are acknowledged as vital measures for addressing these challenges.
Among these technologies, Subsurface Drip Irrigation (SDI) stands out as particularly effective in delivering water and nutrients to plant roots. Unlike surface Drip Irrigation (DI), which is widely adopted globally, the utilization of SDI systems remains relatively uncommon. This is particularly noteworthy given the well-documented evidence derived from field research and practical applications in (semi-)arid regions, underscoring the considerable potential of SDI systems in enhancing plant water use efficiency [2]. However, the limited use of SDI systems emphasizes the need for careful adaptation of system design and management to local conditions and agricultural practices to ensure effective implementation.

2. Materials and Methods
A field experiment was conducted in the Fès-Meknès region, Morocco, comparing DI and SDI Systems alongside other water-saving strategies, namely Deficit Irrigation and mulching. Aim of the tree factorial trial in Split-Plot design with four Blocks was to evaluate the effects of the experimental factors on growth and yield parameters for potato (Solanum tuberosum) in the summer growing season 2023 from March to July and for field peas (Pisum sativum) in the subsequent winter period from October 2023 to February 2024.

3. Results and Discussion
For potatoes, the trial clearly showed the challenging nature of successful and uniform crop germination when using SDI under hot and dry weather conditions. Heterogeneous germination and development patterns under subsurface irrigation led to a significant reduction of tuber yield (30.73±10.45 t ha-1) compared to the DI treatment (40.80±7.41 t ha-1) by about 10 tons per hectare. However, contrasting results of tuber yield from individual, early-germinated SDI potato plants underscored the potential of SDI Systems for this crop.
Results for the field peas cultivated as short cycle crop during the winter period 2023/2024 showed a clear positive impact of mulching, with peas reaching more than 20 % higher yields in mulched versus unmulched treatments. Additionally, in line with the results from potato crop, plot yield of peas was significantly reduced when irrigated by SDI (4.67±0.93 t ha-1) compared to surface irrigation (5.33±0.90 t ha-1). Field observations indicated that pea plants growing in SDI plots experienced water stress during early developmental stages, possibly due to the need for the plant roots to adapt to the subsurface water source after an initial period of high soil moisture in upper soil layers due to precipitation. The analysis of yield parameters from single plants supports this theory, showing significant lower numbers of peas per plant in SDI versus DI treatment. Anyways, results from single plants also show that subsurface irrigated plants were able to compensate the lower number of peas per plant by higher thousand kernel weight, resulting in a yield per plant at the same level for subsurface as for surface irrigated peas.
In conclusion, the findings underscore the need to implement management best practices for SDI systems in the germination and early development stage of crops. Once plant stands are well-established, SDI has proven to be an efficient irrigation and fertigation system under the semi-arid climate of central northern Morocco, combinable with other water-saving strategies.

4. References
1. Fader, M.; Shi, S.; Bloh, W. von; Bondeau, A.; Cramer, W. (2016): Mediterranean irrigation under climate change: more efficient irrigation needed to compensate for increases in irrigation water requirements. Hydrol. Earth Syst. Sci. 20 (2), 953–973.
2. Sinobas, L. R.; Rodrguez, M. G. (2012): A Review of Subsurface Drip Irrigation and Its Management. Lee, T. S. (Ed.): Water Quality, Soil and Managing Irrigation of Crops, 171–194.

Speaker: Helen Kretzschmar (Humboldt Universität zu Berlin)

202_Kretzschmar.pptx

159 Optimization of agricultural land use to support sustainable and healthy diet: a Bayesian approach coupled with soil-crop modelling

In recent decades, a significant global shift in our food system was observed, marked by increased consumption of high-calorie diets, processed foods, and animal products. This trend led to a surge in obesity, cardiovascular diseases, and non-communicable diseases [1,2]. To sustain this food system and meet the needs of a growing population, agriculture underwent transformation with the adoption of high-yield crop varieties, chemical fertilizers, pesticides, and mechanization [3]. This transformation brought forth environmental challenges, notably by contributing to 30% of global greenhouse gas emissions [4] and 70% of freshwater use [5]. Conversion of natural habitats to farmland led to biodiversity loss [6], while overuse of fertilizers and pesticides resulted in eutrophication zones [7], and health issues [8]. Various proposals emerged to address these challenges [9], with a key focus on shifting towards sustainable and healthy diets [10]. Reference diets, such as the one proposed by the EAT-Lancet [11] commission or the TYFA project [12], propose universal guidelines for a healthy food supply which respect planetary boundaries.

Taking Wallonia as a case study, the aim of this work is to design cropping systems aimed at locally supporting sustainable and healthy diets, while activating agroecological levers.

Considering i) the estimated needs of the Walloon population based on reference diets [11,12] and ii) the various pedoclimatic contexts and agronomical potentials of Wallonia, the Bayesian optimization algorithm DREAM [13] was used to optimize the allocation of the different agricultural productions within the available land use. From the optimization, cropping systems were designed for each region, in co-construction with stakeholders (scientists, farmers, food chain actors, etc.). The mechanistic model STICS [14] was then used to simulate the agronomic and environmental performances (e.g., yield, carbon storage, nitrogen cycle) of some of these cropping systems, under reference pedological contexts, for current and future climatic conditions, to evaluate their sustainability and resilience.

On the one hand, preliminary results indicated that optimizing land use to meet the population's needs should be feasible under current climatic scenarios, with still some spared arable lands. Since the optimization of land use was based upon actual yield, it seemed that the available spared land could mitigate the yield decrease that usually accompanies the implementation of more environmentally sustainable but less productive techniques (e.g., reduction of chemical pesticides or mineral fertilizers).

On the other hand, the initial predictions from the STICS model indicated significant yield increases of 10 to 20% by 2050 (for RCP 4.5 and 8.5 respectively) for potato cultivation, and by 30% for wheat, while no changes were observed for legume crops, and conversely, rapeseed cultivation sees its yields decreased by 20 to 30% compared to the current scenario.

Regarding cereal crops and potatoes, the increases in yields due to CO2 fertilization is likely to compensate for yield losses due to activation of agroecological levers. However, the predicted yield losses for some other major crops indicate that a redesign of rotations and the implementation of adapted management practices will be crucial to adapt to future scenarios.

References
1. Anand, S. S. et al. J. Am. Coll. Cardiol. 66, 1590–1614 (2015).
2. Popkin, B. M. et al. Nutr. Rev. 70, 3–21 (2012).
3. Matson, P. A. et al. Science 277, 504–509 (1997).
4. Whitmee, S. et al. The Lancet 386, 1973–2028 (2015).
5. Molden, D. Earthscan, London, 48 p. (2007).
6. Newbold, T. et al. Nature 520, 45–50 (2015).
7. Conley, D. J. et al. Science 323, 1014–1015 (2009).
8. Van Maele-Fabry, G. et al. Cancer Causes Control 21, 787–809 (2010).
9. Springmann, M. et al. Nature 562, 519–525 (2018).
10. Tilman, D. et al. Nature 515, 518–522 (2014).
11. Willett, W. et al. The Lancet 393, 447–492 (2019).
12. Poux, X. et al. ddri-AScA, Study N°09/18, Paris, 78 p. (2018).
13. Vrugt, J. A. et al. Hydrol. Earth Syst. Sci. 15, 3701–3713 (2011).
14. Brisson, N. et al. Eur. J. Agron. 18, 309–332 (2003).

Speaker: Tom Desmarez (Gembloux Agro-Bio Tech)

160 Adapting Italian agriculture to climate change: a MONICA model analysis of chickpea and lentil production for enhanced yield stability in low-input systems

Climate change significantly impacts legume crop production systems, necessitating adaptive crop management strategies (1), especially in low-input agricolture. In response, our study utilizes the MONICA crop model (2), previously refined and validated with chickpea and lentil field trial data from Europe, to forecast the response of these crops to upcoming climate variations throughout Italy. Central to our research are two critical inquiries: firstly, how will anticipated shifts in chickpea and lentil phenology under future climate scenarios affect yields across Italy, and will these impacts be consistent across the peninsula or lead to changes in preferred cultivation areas? Secondly, we explore strategies that Italian farmers could adopt to accommodate these phenological changes, aiming to mitigate yield reductions and maintain stability over time, thereby optimizing legume production sustainably without reliance on external inputs.

The MONICA model, meticulously calibrated for commercial chickpea and lentil cultivars using detailed field trial data, simulates these crops effectively. Deployed across Italy in a 1 km² gridded format, the model offers a thorough analysis of how varying climate conditions, particularly drought and heat stresses, will impact crop phenology and yield.

Our study is organized around two separate 30-year simulation intervals: a historical baseline period from 1980 to 2010, and an intermediate future period from 2040 to 2070, examining two different IPCC emission scenarios (SSP2-4.5 and SSP5-8.5). This methodology allows for an in-depth analysis of climate change's effects on the growth and development of chickpea and lentil, particularly examining shifts in the timing of flowering and maturity to assess phenological changes and the associated effect on grain formation.

Initial findings indicate significant changes in phenology , particularly affecting the timing of flowering and maturity, which in turn impacts the entire crop cycle. The study further explores adaptive strategies by evaluating several aspects such as yield, quality of yield, stability of yield, economic implications, water use efficiency, and soil fertility, focusing especially on nitrogen levels.

The study evaluates four distinct crop rotation and management strategies:

Benchmark: A conventional Italian 4-year rotation comprising legume (chickpea/lentil), wheat, maize, and barley.

Autumn Shift: The Benchmark rotation, but with chickpea and lentil sown in autumn.

Sustainable: Replacing maize in the Benchmark rotation with an N-fixing crop, resulting in a legume, wheat, legume, and barley sequence.

Sustainable Autumn Shift: The Sustainable rotation with autumn sowing for chickpea and lentil.

These approaches are examined under the different various climate scenarios to evaluate their ability to adapt to expected yield reduction. Preliminary results suggest that adjusting sowing dates and altering crop rotations can significantly impact yield, yield stability, and overall agricultural sustainability (in terms of water and nutrient use efficiency). Notably, crops planted in autumn, particularly within sustainable rotations, show promise in adapting to these shifts, potentially resulting in more stable yields and environmental benefits.

Our research seeks to provide Italian farmers with actionable insights, helping them adjust sowing dates and management practices to maintain sustainable legume production under the challenges posed by climate change. Moreover, this study proposes a model that could be extended to other regions and crops, enhancing our comprehension of agricultural adaptation strategies in response to climate change.

(1) Ahmed, M., Sameen, A., Parveen, H., Ullah, M.I., Fahad, S., Hayat, R. (2022). Climate Change Impacts on Legume Crop Production and Adaptation Strategies. In: Ahmed, M. (eds) Global Agricultural Production: Resilience to Climate Change . Springer, Cham. https://doi.org/10.1007/978-3-031-14973-3_5
(2) C. Nendel, M. Berg, K.C. Kersebaum, W. Mirschel, X. Specka, M. Wegehenkel, K.O. Wenkel, R. Wieland, The MONICA model: Testing predictability for crop growth, soil moisture and nitrogen dynamics, Ecological Modelling, Volume 222, Issue 9, 2011, Pages 1614-1625, ISSN 0304-3800,https://doi.org/10.1016/j.ecolmodel.2011.02.018.

Speaker: Alessandro Triacca (Sant'Anna School of Advanced Studies)

332_Triacca.pptx

12:40 PM Lunch break

Wrapping-up session & introduction to ESA 2026

Conveners: Claas Nendel, Edith Le Cadre, Evelin Loit-Harro

wrappring-upSession_LeCadre.pdf

3:05 PM Coffee break