The low resistant erosion ability of ground substance, especially in granite weathering crust and purple rock and its soil are the inner causes of severe soil erosion.

• 抗侵蚀性较弱的地面组成物质，特别是花岗岩和紫色岩风化壳及其土壤，是造成土壤侵蚀特别严重的内在原因；