No till in rainfed agriculture in Western Africa - Perspectives and challenges

No-till agriculture is promising in Western Africa. Rainfed agriculture is the rule, and water is scarce. The first rains fall on a bare soil, prone to runoff. No-till techniques have been shown to limit runoff in a striking way. Nevertheless, their application to the cropping systems is not an easy task. No-till agriculture is based mainly on protecting the soil surface with crop residues throughout the year, and on external mineral inputs. In Western Africa, crop biomass is scarce and used almost completely for livestock feeding in the dry season. External mineral input is also scarce, and crop production relies heavily on soil organic matter mineralization. Thus, even if no-till techniques seem promising in Western Africa, they also face great challenges, and scientific research needs to be undertaken in close collaboration with farmers. During the first days of this conference, the possible contributions of no-till agriculture to sustainability have been presented with high enthusiasm as a response to the critical situation of African agriculture, which is probably not sustainable in its present form, particularly in a semi-arid climate. Rural population densities are rising, making fallow practices disappear. Alternative solutions for rainfed agriculture are sought. No-till agriculture could also contribute in these ecologies. Nevertheless, conservation agriculture is still not practised in Mali. Why is this? (Résumé d'auteur