Crop-livestock interactions in the West African drylands

Many semiarid regions of Sub-Saharan Africa (SSA) are experiencing vast increases in human population pressure and urbanization. These augment the demand for agricultural products and have led to the expansion, intensification, and often closer integration of crop and livestock production systems. The transition of crop and livestock production from the current relatively extensive, low input/output modes of production to more intensive, higher input/output modes of production presents numerous challenges to the achievement of required long-term production increases from these farming systems. This paper provides an overview of the challenges facing agricultural production in semiarid SSA with a focus on West Africa. A description of mixed crop–livestock farming systems and their evolution is followed by an overview of the principal linkages between crops and livestock: income, animal power, feed, and manure. The most detailed discussions relate to nutrient cycling in these farming systems. Most livestock derive their feed almost exclusively from natural rangeland and crop residues, and livestock manure is a precious soil fertility amendment. However, most farmers have insufficient livestock and therefore manure to sustain food production. Nutrient harvests from cropland often exceed nutrient inputs, and soil nutrient depletion is a principal concern. The paper concludes with a discussion of strategies that may improve the productive capacity of these mixed farming systems