Assessment on the Soil Retention Service of Water Erosion in the Nile River Basin Considering Vegetation Factor Variance from 1982 to 2013

Water erosion has negative effects on agricultural productivity in Africa. The cover management factor (C factor) related to vegetation is the most influential parameter in the estimation of water erosion and reflects key interrelated cover and management information on the soil retention service of water erosion. However, the estimations of C factor on a large-scale display large differences. The Nile River Basin has suffered severe water erosion for several decades, while the soil retention service of water erosion from vegetation is still unclear. This study assesses the spatiotemporal change in soil retention service in the Nile River Basin from 1982 to 2013, based on the Revised Universal Soil Loss Equation (RUSLE) model. The comparison of six kinds of estimation methods showed that four methods could be used, whereas the other two were inappropriate. The average annual soil retention service based on the C factor variance ranged from 934.08-1240.56 (t ha(-1)y(-1)), and spatially increased from south to north. The area of significant increasing and decreasing tendencies were 1.31 x 10(4)-1.94 x 10(5)km(2)and 5.68 x 10(3)-3.81 x 10(4)km(2), respectively. These results provide a reference for the selection of C factor methods and spatiotemporal evidence of the soil retention service of water erosion in the Nile River Basin.