Assessment of Soil Erosion in Qinjiang Watershed Based on GIS and USLE

Soil erosion intensity of Qinjiang watershed was evaluated based on USLE model by applying GIS and RS technology,and analyzing characteristics and disciplines of different elevation,slope and land use types.The results show that:(1)the average soil erosion rate in the whole year was 2 608.87t/(km2·a), belonging to the moderate erosion,but this level was larger than the soil loss tolerance of 500t/(km2·a)in north red soil region ruled by the Ministry of Water Resources;(2)based on different altitude gradient in the research area,soil erosion intensity was in reverse proportion to the increase of the elevation gradient,so, the 0~240melevations was the key area of soil erosion prevention;(3)based on different slope gradient in the study area,soil erosion intensity was in reverse proportion to the increase of the slope gradient,the slope less than 15°was the key area of soil erosion prevention and management;(4)soil erosion intensity differences under different land use types in study area were significant.Dry farmland,grassland and unused land mainly distributed in the serious erosion area,which was the key land use type to control the whole soil erosion intensity in watershed.