Carbon sequestration and farm income in West Africa: Identifying best management practices for smallholder agricultural systems in northern Ghana

The interest in agricultural soils as global storage of carbon has increased in recent years, along with the prospect of farmers' participation in payment schemes under the Clean Development Mechanism of the Kyoto protocol. Thus, a better understanding of agricultural practices that can increase soil carbon and enhance the livelihoods of farmers is necessary, particularly in smallholder farming systems of West Africa. This study evaluates different crop management strategies both by their capacity to sequester carbon in agricultural soils and by their contribution to household income. A case study in Wa, Upper West Region of Ghana is used to test 48 different cropping strategies by means of a crop simulation model and a household-level multiple-criteria optimisation model. Each cropping strategy is evaluated after a 20-year simulation period by its capacity to accrue carbon in the soil, by its economic performance at the plot-level, and by its contribution to the farm income with and without carbon payments. A set of best management practices that concomitantly increase soil carbon and farm income are identified and classified by their cost of investment.