Towards sustainable soil management in sub-Saharan Africa

The low productivity of agriculture in sub-Saharan Africa is largely due to the degradation of soil fertility. Family farming, the cornerstone of food security in this vast region, faces the challenge of restoring and maintaining the land's productive capacity. Farmers' endogenous practices, such as cereal-legume intercropping, grazed fallows and tree plantations, are no longer able to maintain fertility on expanding cultivated areas, especially when soils are deficient. For four decades, decision-makers and stakeholders in the agricultural sector have favored the widespread use of synthetic fertilizers. However, the use of mineral fertilizers remains low and well below the global average (15 kg/ha versus 135 kg/ha). Having long promoted the use of organic manure, research is now encouraging the diversification of biomass sources through agroforestry, intercropping with legumes and conservation agriculture. Water and soil conservation techniques have also been put forward. It is indeed the combination of soil fertility management practices that needs to be developed with farmers for each production situation, depending on locally available resources, a rational use of synthetic fertilizers, and farmers' and scientists' knowledge. To achieve this goal, it is necessary (i) to modify the postures of researchers and decision-makers towards rural people, and (ii) to revise public policies that still focus on the use of mineral fertilizers, in order to provide more diversified, high-performance advisory services that integrate the requirements of the agroecological transitions, which are essential today in a context of climate change.