Geospatial Modelling of Soil Loss at Lagos, Ogun, Osun, Ondo, Ibadan and Ekiti in Southwest, Nigeria

Abstract

In the southwest of Nigeria, mass movement processes and soil erosion have spread, making management and conservation strategies costly and challenging to implement throughout the region. The objective of this paper investigated the Geospatial Modeling of Soil Loss at Lagos, Ogun, Osun, Ondo, Ibadan and Ekiti in Southwest, Nigeria using Revised Universal Soil Loss Equation (RUSLE) model with the integration of geographic information system (GIS) and remote sensing techniques to assess the risk of soil erosion and hotspots in the area. Data generated show that the estimated values of rainfall erosivity (𝑅), soil erodibility (𝐾), topography (𝐿𝑆), cover and management (𝐶), and support practices (𝑃),  ranged between 148.33 and 2143.47 MJmmha-1 h-1 yr-1, 0.04 to 0.28 megajoules per hectare hour megajoules-1 hectare-1 millimeter-1, 0 and 918.264, 0.01 to 0.33, and 0.2 to 1, respectively. GIS raster calculations derived from these factors revealed a mean estimated soil loss rate of 0-1337.6t/h/yr. (tons per hectare per year). This study discovered that the primary causes of soil loss in the area were poor vegetation cover, steep and long slopes, and high rainfall erosivity. In order to reduce soil erosion in the research area, the study emphasizes the need for quick action. This study also recommends more research that prioritizes severity analysis areas and estimates sediment loss throughout the region in order to develop appropriate conservation and management methods.