Soil conservation assessment via climate change and vegetation growth scenarios in the Nile River basin

Soil conservation by vegetation can mitigate soil erosion hazard and prevent reductions in food productivity. However, previous research applies little consideration to the interaction between vegetation and climate change in the estimation of future soil conservation change. Therefore, based on the Revised Universal Soil Loss Equation (RUSLE), Representative Concentration Pathways (RCPs, specifically RCP4.5 and RCP8.5), and the vegetation index and precipitation datasets, we built a multivariate regression equation that considers changes in vegetation growth under climate change scenarios in the context of soil conservation. Using the Nile River basin as a case study, via our established methods, we modelled and projected the impact of vegetation and climate change on future soil conservation between 2020 and 2100, where three main results were obtained: (1) under the scenarios of RCP4.5 and RCP8.5 from 2020 to 2100, soil conservation in the Nile Basin will first increase and then decrease, with its highest value in the years 2060, at 117.72 (t ha−1 y−1), and 2070, at 134.39 (t ha−1 y−1). (2) Soil conservation under RCP4.5 is lower than that under the RCP8.5 scenario, with a maximum difference of 27 (t ha−1 y−1) in 2040 and a minimum difference of 0.2 (t ha−1 y−1) in 2100. (3) The vegetation and climate change models in 2100 had soil conservation values of 110.77 (t ha−1 y−1) under RCP4.5 and 38.70 (t ha−1 y−1) under RCP8.5. In conclusion, although vegetation growth can increase soil conservation in the Nile River basin, the change in precipitation can offset the soil conservation enhanced by vegetation growth.