Assessement of soil erosion susceptibility in Maga, Sudano-Sahelian zone (Far North Cameroon): contribution of RUSLE model coupled with a GIS

Water erosion is a major environmental, agronomic and economic challenge that has a major impact on food security in Africa. It is a real problem that impacts the socio-economic development of rural world, through huge losses of land in a very fragile ecosystem whose soils are poor and poorly protected, exposed to anthropo-ecological effects, amplified by climate variability and imbalance. The aim of this study is to assess degree of susceptibility to water erosion in Maga (Far North Cameroon) and to Model out the priority vulnerable areas in order to make recommendations and possibly take action. The Revised Universal Soil Loss Equation (RUSLE) integrated into a Geographic Information System (GIS) is the most appropriate methodological approach for assessement susceptibility to erosion, with the contribution of pedological, topographical, climatic and land-use data. Multi-criteria cross-referencing establishes the erosion susceptibility map, according to the level of risk, including very high risk (6 %), high risk (18 %), moderate risk (15 %), low risk (19 %) and very low risk (36 %). The morphology of the large basin (1400 m) with high average rainfall in the Mandara Mountains (900 mm/year) immediately influences the dynamics of the low to zero slope “Yaeres” with a run-off process that modifies the surface properties of the soils (sandy and sandy-clay), with a frequent water deficit, due to their low organic matter content (≤2 %) are very sensitive to erosion. Soil particles are scattered and very compact, due to the absence of plant cover and poor farming practices. In addition, overgrazing, population growth, tree felling, uncontrolled bushfires and dilapidated water infrastructure all contribute to erosion and the emergence of gullies, loss of biodiversity, reduced fertility and lower agricultural yields. Erosion thus affects the sustainability of soil and water resources, in particular the longevity of dam reservoirs and the recharging of aquifers in a very fragile ecosystem, giving way to land degradation and the advance of desertification, which have become increasingly urgent over time and on a spatial scale. Their impact is felt on the economy, the environment and the well-being of populations, particularly rural populations who depend on these resources.