Stratification of soil aggregation and organic matter under conservation tillage systems in Africa

Soil degradation due to tillage has been reported Africa-wide. Other main causes of soil degradation are overgrazing, extensive cultivation of marginal lands, widespread clearing of vegetation for agriculture, deforestation, exploitation of unsuitable agricultural technologies, mis-management of arable lands, and frequent drought. Hence, declining soil fertility and increasing population pressure on lands are fragile bases on which to build expectations for improved crop production. This paper recognizes conservation tillage systems as one means for preventing food shortages and natural resources degradation throughout the continent. Conservation tillage has the potential for increasing soil organic matter content and enhancing soil aggregation. Conservation tillage systems can create an aggregated, fertile surface layer that is important from a soil erosion reduction perspective and thus for a sustainable agriculture in Africa. Some indigenous tillage systems in Africa can be adapted to meet objectives of conservation tillage systems. Further, recent technological developments in tillage and seeding machinery will certainly enhance the rate of farmer’s acceptance and adoption of conservation tillage.