Estimation of the economic losses caused by soil erosion in Zhuxi small watershed by GIS and USLE.

Based on SPOT remote sensing data of Zhuxi small watershed in 2007,the watershed soil erosion quantities were worked out by using the geographic information system(GIS) and universal soil loss equation(USLE),and according to tthe basic principles and methods of environment economics,the economic losses were estimated which included soil nutrient loss,water loss,land loss,sediment retention and accumulation etc.The results show that the soil erosion amounts to 42 893.96 t in the studied watershed,and the soil erosion modulus is 954.047 t/(km2·a).The total cost of soil erosion is 9 575 070 yuan,which means that the annual economic losses caused by erosion in the watershed is 212 967 yuan/km2,corresponding to 27.33% of the total local agricultural and sideline output.The research result indicates that soil erosion causes directly the decline of land productivity in the Zhuxi watershed and clogs the agricultural development.