Combining on-farm innovation tracking and participatory prototyping trials to develop legume-based cropping systems in West Africa

International audience In the cotton-production zone of Burkina Faso, poor soil fertility and limited access to appropriate fertilizers call for alternative approaches to sustain productivity, such as the introduction of more legumes into the agroecosystem. Legumes have nearly disappeared from local cropping systems under the pressure of the cotton monocropping model. To develop new legume-based cropping systems using a bottom-up approach, this study was based on local farmers' agroecological innovations. In a first step, called on-farm innovation tracking, five innovative legume-based cropping systems were identified and characterized on farms located in the study area through interviews with "innovative farmers" who had designed and implemented these cropping systems: (i) Sorghum and legume (cowpea, soybean or peanut) intercropping in rotation with maize or cotton; (ii) Soybean as a cash crop in rotation with maize or cotton; (iii) Red cowpea intra-annual succession with a biomass crop; (iv) Mucuna in rotation with maize; and (v) Pigeon pea in rotation with maize. In a second step, these five "innovative cropping systems" (ICSs) were implemented in "participatory prototyping trials" (PPTs) in two communities located in the study area were they were evaluated during field days by local farmers ("field-day farmers") having no previous experience with ICSs. By comparing evaluations made by innovative farmers with those of field-day farmers, it was shown that (i) locally implemented ICSs adapted to local drivers of change are of great interest to other farmers, and (ii) the study's two-step participatory approach is an original and relevant way to co-design and introduce innovations.