Improving Soil Quality and Crop Productivity Through Conservation Agriculture in West Africa.

The challenges to increase grain yields and soil quality in West Africa largely revolve around environmental and economic constraints. Improving grain yield and soil quality will require the adoption of innovative crop rotations that employ both local and improved conservation agricultural practices (CAPs) such as reduced tillage, crop residue, legume cover crop, and integrated nutrient, water and pest management practices. Our goal is to provide food security by increasing economic returns to smallholder farming households dependent on rain-fed agriculture, through gender-sensitive farmer participatory development, and dissemination of sustainable CAPs. Surveys and meetings were conducted with farmers and treatments for testing were identified and implemented. To evaluate long term impacts of CAPS, mother trials with several components/treatment (<5) of CAPS with 3 to 5 replications and baby trials with few (<3) involving several farmers test-plots (78 in Ghana and 60 in Mali) were implemented. Treatments mainly included components of minimum tillage, crop residue management, crop rotations, water harvesting techniques and integrated fertilizer and weed management practices. One of the components of CAPs dealing with permanent groundcover, especially with cover crop is challenging to farmers because of conflicts with livestock management a key component of farming systems; and due to alternative uses of residues and problems with free animal grazing. Soil in most of the farmers fields were poor and had low soil organic carbon in upper west region of Ghana. Sole crops of maize or soybean produced greater grain yields and crop residue than intercropping in conventional tillage or minimum tillage. There was no significant difference in maize yield under conventional tillage or no-tillage in continuous maize cropping system. Soybean yields were increased with fertilizer application, particular phosphorous under both conventional and no-tillage conditions. Soybean growth and yield was not affected by tillage, residue management or the interaction of tillage and residue management. Although residue and grain yields tended to be higher under conventional tillage than under no-till. Maize planted on tied ridges, and tied ridges with grass strips or pigeon pea strips produced higher maize residues than maize planted on flat, and flat with grass strips or pigeon pea strips. Our results suggest that there are some opportunities to increase crop yields through use of intensive sustainable agricultural practices such as application of fertilizer, minimum tillage, crop rotations and water management practices.