GIS支持下土壤侵蚀潜在危险度的分级研究

根据土壤侵蚀特点，在IDRISI地理信息系统（GIS）支持下，研究设计了小流域空间与属性数据库的建设，在GIS系统支持下可有效地实现区域土壤侵蚀潜在危险的分级及其空间分析。首先，采用侵蚀预报的数学模型来估算土壤侵蚀星，用土壤详查资料编制土层厚度和土壤容重图，然后，由土壤年均侵蚀量，土层厚度和土壤容重得到土壤抗蚀年限图，按水利部标准将土壤侵蚀潜在危险度分为5级。最后，为表明某一地区或地类土壤侵蚀潜在危险的大小，还提出了土壤侵蚀潜在危险指数（SEPDI）。以三峡库区的王家桥小流域为例进行了研究，并且分析了其空间分布特点。

STUDY ON GRADATION OF SOIL EROSION POTENTIAL DANGER USING GIS

Through the analyses of soil erosion characteristics, based on Geographical Information System of IDRISI, we designed spatial and attributive database of small watershed. Gradating the potential danger of soil erosion and its spatial distribution is easy to analyses with this system. First, soil erosion modulus can be estimated by using water erosion model, and the maps of soil density and soil horizon thickness can be derived from soil detailed survey data. Then the years of soil loss by erosion is calculated by soil erosion modulus, soil horizon thickness and soil density. According to the standard of Ministry of Water Resources, the potential danger of soil erosion can be divided into 5 grades. At last, in order to measure the potential danger of soil erosion, the index of soil erosion potential danger (SEPDI) is put forward. A case study was done in Wangjiaqiao watershed in Three Gorges Area, and its distribution characteristics were analyses using GIS.