Soil erosion types in the loess hill and gully area of China

The loess hill and gully area of China is the region with the most serious soil erosion in the world,and there is an urgent need for erosion control and soil conservation.This project uses a geographic informationsystem (GIS) for studying soil erosion types. Elevation contours from a topographic map of the study area weredigitized to generate a digital elevation model(DEM). Slope and aspect were then computed from the DEM.The current land uses were obtained by air-photo interpretation. DEM , slope , aspect and landuse were inte-grated by GIS and their interrelationships were analysed. Combining GIS analysis and erosion survey, a rule ofvertical distribution of soil erosion types from hill top to gully bed was derived. The basic erosional systems inthis area were described at the catchment level. This systematic analysis will help to organize erosion surveysand mapping and also to guide conservation strategies.