Assessment of soil erosion impacts in Musanze district, Rwanda

Abstract

In Rwanda, soil erosion is one of the prevalent environmental issues. Soil erosion associated with agriculture practices in Rwanda leads to a decline the soil fertility, brings on a series of negative impacts of environmental problems, and has become a threat to sustainable agricultural production and water quality. As a case study, this study assesses soil erosion level and their impacts in the Kinigi, Nyange, and Shingiro sectors of Musanze District, Rwanda. Estimating soil erosion levels and assessing socio-economic and land degradation impacts were achieved using the Revised Universal Soil Loss Equation (RUSLE) based on five factors related to rainfall, soil characteristics, topography, support practice, and land use land cover management. Field surveys and interviews with local communities of 385 households help gather data on the socio-economic impacts, focusing on changes in agricultural productivity and livelihood, environmental factors, infrastructures, and livelihood and community wellbeing. Based on interviewers' findings, contouring, planting trees, and terracing were taken as measures in soil protection from erosion; and land degradation impacts, specifically concerning soil nutrients fertilizer effectiveness due to soil erosion in the study area. The Nyange sector faces severe erosion (62.05 to 640 tons/ha/year), and Kinigi and parts of Shingiro experience moderate to high erosion (29.52 to 107.08 tons/ha/year). In comparison, areas near Virunga National Park have lower erosion (2 to 29.52 tons/ha/year). Erosion impacts include increased agricultural costs (40%), property damage (33%), and land degradation affecting soil nutrients, with nitrogen, phosphorus, and potassium levels varying significantly across erosion intensity levels.