Opportunities and risks of double cropping in southwestern France with a focus on soybean and sunflower crops

Growing a second food, fodder or bioenergy crop during the fallow period commonly refers to sequential double cropping or relay cropping practices, as a function of sowing date (following or within the primary crop, respectively). Such practice may generate an additional income while supplying support and regulation services. As such, it could be referred as a form of ecologically intensive agriculture but also an opportunity offered by climate change. The decision-making process in the adoption of double cropping relies on many factors related to soil and climate conditions, but also on profit expectation and risk perception. The CASDAR project “3C2A: Three crops in two years” (2019–2023) strived to create references for sequential double cropping in the South-West of France, which encompasses the regions of Nouvelle-Aquitaine and Occitanie. The project focused mainly on grain crops and raised the interest of the use of oil-protein crops such as soybean (Glycine max (L.) Merrill) and sunflower (Helianthus annuus L.) for such practice. As a preliminary contribution of 3C2A project, this paper aims at illustrating the potential interest of soybean and sunflower as double crops in the South-West of France through a qualitative analysis of farmers’ perceptions about the risks and opportunities of double-cropping completed by a 4-years on-farm evaluation of agronomic and economic performances of this practice (110 fields).