Simulation of Soil Erosion to Support Sustainable Land Management in the Mo River Basin (Togo, West Africa)

Abstract

This paper examines possible management pathways to address soil erosion issues due to improper land management and landform patterns. Therefore, a landscape management and planning tool (LAMPT), a spatially explicit model based on the Revised Universal Soil Loss Equation (RUSLE) adjusted for the sediment delivery ratio (SDR) was used to model the historical soil loss and evaluate the efficiency of some land management and conservation strategies. Different database and field characterization were used to calibrate the model for the Mo river basin and validate the model outputs at the landscape level. In addition, a participatory rural appraisal approach was used to validate the simulated spatial patterns of soil erosion at the landscape level. The results indicated that the simulated net soil loss (NSL) for the Mo basin was higher than the tolerable limits for the Tropics. The local appraisal of soil loss was in line with the simulated outputs even though quantification was not accounted for when dealing with rural illiterate people. Simulated historical NSLs were approximately 26, 23, 27, and 44 Mg ha-1y-1, for 1972, 1987, 2000, and 2014, respectively. Steep slopes (≥ 15 ᴼ), poorly covered lands, and riversides (distances ≤ 100 m) are critical areas of sediment sources. Measures, such as controlling erosion hotspots through land protective measures, could help reduce the NSL up to 70%, closer to the tolerable limits for the tropics. The model implementation in the basin showed insights in identifying soil erosion-prone areas and targeting soil conservation planning and landscape restoration measures.