Improving Soil Quality and Crop Productivity Through Conservation Agriculture in Mali, Western Africa.

Declines in crop yields (21% for sorghum and millet) and soil fertility (29% for C) have made conservation (CA) a significant management option for selected cropping systems of Mali. Baseline assessments and rapid rural appraisals have indicated that the classical CA components need to be modified, not only to remove permanent soil cover, but also to include capturing rainwater. The improved conservation agriculture production systems (CAPS) account for 40 to 70% running off rainwater and feeding cover crops and crop residues to cattle, which is a key component of local production systems.

Capturing rainwater by contoured ridge tillage (also known as ACN), have reduced runoff by 40%, increased the wetting front of soil water by 60%, crop yields by 30 to 50%, and soil organic carbon by 40%. Other significant impacts of ACN’s were reported by farmers, such as rise in the ground water table, increased tree regeneration, early onset and late ending of the cropping season. Reducing tillage by direct seeding did not improve yield, yet it did not reduce it as thought by farmers. Only 10 to 20% of the crop residues left to the field at harvest have escaped grazing and remained at the start of the new cropping season. Planting Brachiaria brizantha, as cover crop, at the same time as sorghum, millet and maize has a depressive effect (8 to 19%) on grain yields of these cereals.

Interaction effects of the above CAPS components are strongly likely to improve soil quality and crop productivity in the long term.