Evaluating the soil degradation in Zigui County of the Three-Gorge reservoir area

Indexes and standards for evaluating soil degradation were set up，and the degree,type and spatial change of soil degradation were evaluated in Zigui County.The results show that the purple soil,limestone soil,yellow brown earth and yellow earth are degraded heavily.The degradation of forest and wasteland soil is heavier than that of farmland.The dryland is degraded more greatly than that of paddy soil.In the region,soil degradation mainly trends to form lamellar structure,skeleton,dryland and to decrease nutrient which is short of K and P obviously.As the types and intensities in soil utilization are different,soil degradation is different in spatial.Generally,the soil nutrient degradation is heavier in villages and towns near Yangtze River valley than in mountainous villages far away from the valley.