Estimation of soil erosion supported by GIS and RUSLE: A case study of Maotiaohe Watershed, Guizhou Province

Soil erosion in karst mountainous areas of southwest China is one of the determining factors for land degradation and productivity reduction. To explain the spatial characteristics of soil erosion in karst mountainous areas in southwest China, the authors used the Maotiaohe Watershed in Guizhou Province as study area. Geographic Information System(GIS) technology and the Revised Universal Soil Loss Equation (RUSLE) were applied to estimate the potential and actual amount of soil erosion in Maotiaohe Watershed of Guizhou Province, present the spatial distribution characteristics of soil erosion in the watershed, calculate the soil conservation capacity by land use and then discuss the soil and water conservation countermeasures. Results showed that the soil erosion modulus and the actual amount of soil erosion were 28.70 t/(hm2·a) and 875.65×104 t/a, respectively, and the annual soil conservation amount was 25 095.73×104 t/a. Among land use types, the soil conservation capacity of dry land is the smallest. Apart from the option of returning all the farmland with a slope grade above 25° to woodland or grassland and afforestation in bare mountains, it is imperative to enforce proper management of farmlands with a slope grade of 6°--25°,such as terracing,in order to decrease soil loss.