Assessment of soil erosion in water source area of the Danjiangkou reservoir using USLE and GIS

Abstract

The study is aimed at the evaluation of soil erosion in water source area of the Danjiangkou Reservoir in Henan province, China, using the Universal Soil Loss Equation (USLE) and geographical information system (GIS). The R-factor (rainfall erosivity) was determined by interploation using meteorological data from five stations. The K-factor (soil erodibility) was obtained by using soil survey data. The LS-factors (slope length and steepness) were determined from the digital elevation model (DEM) of the study area, while the C-factor (crop and management) was determined from remote sensing imageries. The P-factor (conservation practice) was estimated from field experiments. The spatial distribution maps of the soil erosion were estimated in study area from 1991 to 2007. The results showed that soil erosion decreased from 44.8 t·hm -2·a -1 in 1991 to 16.9 t hm -2·a -1 in 2007. The total soil loss fell by 9 350 000 t in 2000 and by 13 580 000 in 2007 compared to it in 1991. Soil nutrients loss decreased, such as organic matter loss decreased to 108 397 t·a -1 in 2007 from 226 918 t·a -1 in 1991, total nitrogen and total phosphorus decreased by 7236 t·a -1 and 5640 t·a -1from 1991 to 2007. © 2011 Springer-Verlag.