Co-design and test of biodiversity-based pesticide-free Conservation Agriculture in the long-term CA-SYS platform in France

International audience

إنجليزي. The French National Institute for Agricultural Research (INRA) has established an ambitious experimental infrastructure (the CA-SYS platform) in autumn 2018 after 5 years of co-design with farmers, crop advisors and researchers. CA-SYS covers an area of 125ha divided into 42 fields. The originality of CA-SYS is that it is explicitly conceivedfor the design and evaluation of biodiversity-based and pesticide-free agroecological systems across agriculturallyrealistic scales. An agroecological system will comprise a matrix of fields of one (or a few) cropping systems over anumber of years interacting with adjacent semi-natural habitats (hedges, grass margin strips, flower strips). Thisspatio-temporal arrangement of fields and semi-natural habitats is considered as a coherent strategy, implemented to meet specific goals. CA-SYS has ambitious objectives, including a high multi-performance of systems (profitability and productivity identical to neighbouring farmers over a 10 year-horizon, low environmental impacts, etc.),by maximising the use of biological processes (biological control of pests, improving nitrogen cycling, etc.) andreducing the use of inputs (nitrogen, water, pesticides). Among the four pesticide-free cropping systems tested,CA-SYS tests 2 cropping systems implementing conservation tillage and agriculture principles: a permanent no-tillcover crop-based system (SD1) and a rotation no-till system (SD2). They are both 6-year crop rotation including 7cash crops (buckwheat is cropped as secondary crop in between winter barley and winter wheat). Soil remains covered as much as possible through a high temporal and spatial diversity of cropped-plants. Oilseed rape is croppedwith spring fababean and Berseem clover as companion crops. Fallow periods in between winter wheat/soyabeanis covered by two successive cover crops (i.e. summer and automn sown). Cereals are intercropped with legumes(wheat/fababean, spring barley/spring pea) to enhance crop complementarity. A mix of 4 cultivars are sown foroilseed rape and winter wheat to manage pests.