Erodibility of Agricultural Soils in the Loess Plateau of China

摘要

Soil erosion is more severe in China than that in other countries, and has resulted in a lot of environmental problems. For soil conservation planning and erosion impact assessment, erodibility values for the main soils in China are needed to predict soil loss. The purpose of this study was to choose an index reflecting the impact of soil properties on erosion for soil loss prediction in China, and to calculate a set of erodibility values for main soils on the loess plateau based on the data from several field stations. The standard unit in China was recommended as a plot which is 20 meters long and 5 meters wide with a slope of 15 degree in continuous fallow. The results showed that the soil-erodibility factor K defined as soil loss per rainfall erosion index unit as measured on a unit plot in the USLE more directly and accurately reflects the effect of loess properties on erosion than other available indices of soil erodibility even on the steep farmlands. Values of factor k for loessial soils range from 0.3 to 0.7, with the maximum appearing in Zizhou from where values of k decrease southward, northward, and eastward. The high value 0.61 appears in the tract of Zizhou and Suide from where k values gradually fall southward to 0.3278 in Ansai, eastward to 0.4372 in the region of Lishi, Shanxi, and northward to 0.531 in the watershed of Huangfuchuang river.