Speaker
Description
Introduction:
Success of agricultural operations largely depends on field conditions. A day is considered available if conditions are favourable for both soil preservation and operation success, i.e. if the soil is workable and trafficable and weather conditions appropriated. Predicting available days is thus of prime interest to ensure both soil structure preservation and efficient weeding. The J-DISTAS project created a tool to estimate the number of available days within a period of interest. The MadeInAB project aims at evaluating innovative weed management practices efficiency at the cropping system level. Available days for mechanical weeding are calculated with the J-DISTAS tool to evaluate (i) the tool consistency with real field operations and (ii) the possibility to generalise innovative practices at farm level.
Materials and methods:
Three experimental sites from the MadeinAB project, with contrasted pedoclimatic contexts, were selected for this study: Boigneville (91), Corbas (69) and Kerguéhennec (56). All mechanical weeding operations were registered since the beginning of the experiments (2008, 2014 and 2013 for Boigneville, Corbas and Kerguehennec respectively), resulting in 291 observations.
Available days for mechanical weeding were estimated with the J-DISTAS tool, based on the aggregation of soil workability and suitability of climatic conditions, estimated on a daily basis by the tool (Métais et al., 2023). Estimated available days were then compared with real mechanical weeding operations on the three experimental sites to evaluate the tool consistency. The possibility to generalise innovative practices at farm level was estimated by extrapolating the time required for mechanical weeding operations at the experimental sites to the size of the typical farm in their respective regions.
Results:
Available days estimated by the J-DISTAS tool are more restrictive than real mechanical weeding operations: respectively 34.8, 30.0 and 50.0 % of mechanical weeding in Boigneville, Corbas and Kerguehennec experiments were done during days deemed unavailable by the J-DISTAS tool. The unavailability of these days was mainly due to a poor workability. Nevertheless, when comparing different periods, the J-Distas tool has a good estimation for the situations where the available days are the most restrictive.
At Boigneville, J-DISTAS estimated that there are not enough available days for efficient mechanical weeding of wheat from March to May one year out of five (Figure 1).
Discussion:
The J-DISTAS tool allowed identifying the number of available days for a given cultural operation, here mechanical weeding, for the period considered. Compared to days when mechanical weeding was actually performed, the tool's under-estimations may be partially due to experimenters’ decisions to work sometimes in unfavourable conditions. In addition, its accuracy could be improved by optimising workability calculation: differences between the J-DISTAS estimations and observed operation dates may be partially explained by the depth of workability calculation (10 cm), higher than the real working depths (less than 5 cm).
The comparison between available days and time required to apply the system of Boigneville at farm scale highlighted the risk that the proposed solution could not be implemented at a sligthlty high frequency. Consequently, our recommendations for this site are to be accompanied by strategic advice on the type and capacity of machinery to acquire to be able to implement the innovative practices on real conditions.
Detailed knowledge on factors limiting the availability of days can help (i) identifying the machinery characteristics that could be modified, (ii) changing the schedule or altering the cropping system by allowing a cultural operation in good operation conditions. Further work is currently done to analyse available days for other field operations (tillage and sowing).
Acknowledgements: The authors thank all the contributors to the two projects. J-DISTAS receives subsidy from the CASDAR of French Ministry in charge of Agriculture; MadeInAB receives subsidy from EXPE Ecophyto.
References:
Métais, P., Rogier, N., Dul, P., Ugarte, C., Duparque, A., Martin, D., Duval, R., Billa, P., Lacoste, M., 2023. J-DISTAS : Prévoir les Jours Disponibles pour réussir les opérations culturales et éviter les tassements des sols en grandes cultures. Agron. Environ. Sociétés 13.
| Keywords | workability; soil structure; organic farming system; strategic decision tool; cropping systems evaluation |
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