Speaker
Description
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
| Keywords | diversification;adaptative management;monoring;evaluation |
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