Characteristics and Pattern of Soil Erosion in Central Hills of Sichuan Basin

The Central Hills of the Sichuan Basin is one of the most severe soil erosion in China. The soil erosion is characterized by various erosion ways with special funnelshaped gully erosion, extreme soil erosion rate much higher than that ofthe natural erosion, soil loss from whole soil profile, strong physical weathering of bed rock, obvious parent material erosion and hillterrace erosion. The pattern of soil erosion shows these feathers of rapid runoff and extensive soil washing on hill slope, alterative operating of weathering and erosion, low frequency of water erosion but high strength of water erosion, vertical zoning of soil erosion, soil erosion seasonal variability and nonsynchronization of soil erosion on hill slope and sediment transportation of river. These characters and patterns of soil erosion in this region are related with extensive outcrop of purple sandstone and shale, complicated structures of the surface materials and landforms, obvious seasonal variations of rainfall and local activities of agricultural cultivation. 