红壤区土壤侵蚀危险程度分级初探

土壤侵蚀危险性分级是研究土壤侵蚀危险程度的重要方法.为了探索更加符合实际的土壤侵蚀及其危害程度分级方法,依据水利部土壤侵蚀分级标准和水利部科考成果,对南方红壤科考区的土壤侵蚀强度和土壤侵蚀潜在危险性及其所处流域主要湖泊泥沙输比(SDR)进行分级.结果表明,科考区内轻度、中度、强度和极强度侵蚀均存在.中度侵蚀和强度侵蚀为主要侵蚀类型,占总侵蚀类型的84％.轻度和极强度侵蚀占16％.潜在危险性分级中,无险型、轻险型、危险型和极险型均存在,轻险和危险为主要类型,占总潜在危险类型的84％,无险和极险类型占16％.土壤侵蚀对异地的危害比较大,60％的湖泊SDR＞0.5,其上游土壤侵蚀对异地是危险甚至极险的.研究结果可为红壤全区土壤侵蚀分级和治理工作提供参考.

Preliminary Study of Gradation of Soil Erosion Hazard Degree in Red Soil Region of Southern China

The risk gradation of soil erosion is an important approach to study soil erosion hazard degree.To find a suitable approach to the gradation of soi erosion and its hazard degree in practice,soil erosion degree and its potential risk for the scientific investigation area in the red soil region of Southern China,as well as sediment delivery ratio for the main lakes within the basins in the region,were gradated according to the MWR(Ministry of Water Resources)Standards for soil erosion classification and gradation and the data from the scientific investigation by the MWR.Results showed that there were light,moderate,intense and extremely intense soil erosion degrees in the investigated area.The moderate erosion and intense erosion were the main soil erosion types and accounted for 84% of the whole area,while the light erosion and extremely intense erosion accounted for 16%.The types of no risk,light risk,risk and extreme risk were all found in the potential risk gradation.The light risk and risk were the main risk types and accounted for 84% of all the risk types,while the no risk and extreme ris accounted for 16%.Soil erosion was harmful to the places nearby.Sediment delivery ratios in 60% of the lakes were greater than 0.5,which indicates that soil erosion occurred in the upstream of the lakes is dangerous,even extremely dangerous to the places nearby.Results from the study may offer reference for soil erosion gradation and control in the whole red soil region.