Using GIS and RUSLE to study on the geographical distribution characteristics of soil erosion on the Dianchi Watershed, China

Soil erosion is the primary cause of land degradation, which directly leads to ecological environment deterioration. Nowadays, soil erosion has grown up to be a global public nuisance and have menaced the surviving of human being and the development of society. Fully understanding the soil erosion distribution characteristics is of great significance for formulating reasonable and effective control measures. Based on the RUSLE model and GIS technology, this paper quantitatively analyses soil erosion distribution characteristics in Dianchi watershed, explores the relationship between erosion and topography, such as elevation and slope. The results show that the erosion amount of Dianchi watershed in 2014 was 2,250,100 t a(-1), and the average erosion modulus was 861.09 t km(-2) a(-1). The entire watershed is dominated by tiny erosion, but the intensity of erosion gradually increases from the centre to the periphery. The erosion at the south and north ends of the watershed is most significant. A significant positive correlation was found among soil erosion, altitude and slope. As the altitude increases, the erosion becomes more intenser. As slope increases, the erosion becomes more significant. The average elevation increased by 200 m, and the degree of soil erosion increased by 1.24 times. For each level of slope increase, the soil erosion modulus increased by 497.28 t km(-2) a(-1). Soil erosion mainly occurs in an area representing 17.73% of the basin. Additionally, soil erosion is mainly distributed among areas greater than 2,200 m above sea level and above 35 degrees; thus, this region is the critical area of erosion limitation.