Integrated modelling of soil erosion under land-use and climate change in the Kulfo River Catchment, Ethiopia: implications for climate-resilient management

Abstract Soil is the backbone of agricultural productivity and ecological stability; however, soil erosion, intensified by land use and land cover (LULC) alterations and climate variability, poses a critical threat to these resources. This research investigates the impact of LULC dynamics and rainfall change on soil erosion in the Kulfo River Catchment (KRC), Ethiopia, over the past three decades (1987–2022) and under projected 2050 climate scenarios (RCP 4.5 and RCP 8.5). Historical LULC transitions were assessed using supervised Landsat imagery classification (1987, 2003, and 2022) using the Maximum Likelihood Classification (MLC) approach in ERDAS Imagine, and future transitions were forecasted using TerrSet's Multi-Layer Perceptron-Markov chain model. Soil erosion rates were calculated using ArcGIS' Revised Universal Soil Loss Equation (RUSLE), which combined observed and ensemble-projected rainfall data with LULC information. Results indicate that between 1987 and 2022, agricultural land, built-ups, and agroforestry land expanded at the expense of shrubland, forestland, and grazing land, leading to increased mean annual soil loss from 36.2 tons/ha/year in 1987 to 50.7 tons/ha/year in 2022. Projections for 2050 indicate a further rise to 63.2 and 64.1 tons/ha/year under RCP 4.5 and RCP 8.5, respectively. Notably, forest-to-agriculture conversion emerged as a dominant driver of erosion, with soil loss rates escalating from 85 tons/ha/year under historical conditions to 93 and 95 tons/ha/year across scenarios. These findings demonstrate how crucially rainfall intensification and LULC transitions interact to speed up soil deterioration. It is essential to incorporate this knowledge into watershed management to promote evidence-based soil conservation and climate adaptation planning, maintain erosion-resistant land cover, and direct afforestation projects under Ethiopia's Green Legacy program.