Complementary models and decision-support systems for accompanying stakeholders in managing weeds with few or no herbicides

This paper presents 4 tools for designing herbicide-sparse cropping systems. The "virtual field" model FLORSYS was built from experiments, and can be used to test cropping systems in the long term, with different pedoclimates and weed floras. It predicts many virtual 'measurements' on crops, weeds and soil, as well as indicators of weed impact on crop production and biodiversity. Two decision-support systems co-developed with future users (farmers, crop advisers...) also allow comparing cropping systems, one in terms of weed risk for a series of harmful weed species (OdERA), the other (DECIFLORSYS) with the same weed-impact indicators as FLORSYS. Finally, OPTIFLORSYS combines FLORSYS with optimization algorithms to propose cropping systems that meet the user's production and/or biodiversity objectives.