Application of Chinese Soil Loss Equation (CSLE) to analyze the spatial and temporal variations in soil erosion on the Loess Plateau of China

Soil erosion has been recognized as severe problem for environment protection and human sustainability, especially in the Loess Plateau of China. This study was conducted to evaluate the temporal-spatial variations in soil erosion on the Loess Plateau (taking the Gushanchuan basin as an example) in the past three decades by combining Chinese Soil Loss Equation (CSLE), remote sensing (RS) and Geographic Information Systems (GIS) technology. The results showed that the temporal variation in soil erosion of the past three decades (1975 to 2006) could be divided into two stages. The first stage was from 1975 to 1986, and soil erosion was intensified and eroded area increased by 138.13 km(2), particularly in the southeast part of the basin. The second stage was from 1986 to 2006, and erosion weakened. The eroded area decreased by 163.09 km(2), and the reduction in soil erosion distributed in the entire basin. Soil erosion above the medium degree mainly occurred in the elevation ranging from 1070 to 1300 m, with the slope ranging from 18 degrees to 35 degrees, correspondingly. The erosion above the medium degree had a rainfall erosivity range of 900 to 1150 MJ.mm.hm(-2).h(-1) in 1975 and 2006. The erosion above the medium degree in 1986 and 1997 had a rainfall erosivity ranging from 1300 and 1800 MJ.mm.hm(-2).h(-1). The area with serious soil erosion corresponded to the area distributed with high rainfall erosivity. Soil erosion predominantly occurred in farmlands. In the period from 1975 to 2006, the farmland area decreased while the woodland and pasture areas increased, and soil erosion weakened obviously as a result of land use adjustment. The results of this study would provide references for benefit assessment of soil and water conservation on the Loess Plateau.