重庆市万州区紫色土侵蚀潜在危险度的影响因素

在选择典型地段野外调查的基础上,利用GIS技术实现了重庆市万州区紫色土侵蚀潜在危险度的分级,并提出土壤侵蚀潜在危险度指数(SEPDI),分析了1990年和2005年两个不同时期SEPDI值,对该区紫色土的侵蚀潜在危险度进行了综合评价.评价结果表明,按照水利部颁布的标准,该区紫色土的土壤侵蚀潜在危险度分为3级--无险型、轻险型和危险型;土壤侵蚀潜在危险度指数SEPDI值从1990年到2005年没有显著的变化,1990年的SEPDI值为2.05,2005年为2.07.分析了两个时期土地利用类型、植被盖度、土层厚度、坡度等因素对土壤侵蚀潜在危险度的影响,综合评价了其空间分布特征,总结出研究区造成土壤侵蚀的原因主要是自然地理因素、大规模移民搬迁和水土保持治理措施的不合理.

Influence Factors of Purple Soil Erosion Potential Danger in Wanzhou District of Chongqing City

Based on field investigation in the typical areas,the gradation of potential soil erosion danger is carried out by using GIS technology.Compared with the index of soil erosion potential danger(SEPDI) of two different periods in 1990 and 2005,purple soil erosion potential danger in Wanzhou District,Chongqing City is analyzed.Results show that by the guideline with Ministry of Water Resources' classification standards,the potential danger of soil erosion may be divided into three grades.The SEPDI in 1990 year is 2.05 and the SEPDI in 2005 is 2.07,which indicates that the SEPDIs of two different periods do not have a remarkable change.By analyzing soil erosion potential danger in the two periods under such influence factors of soil erosion as land use type,vegetation cover,gradient level,and soil thickness,the spatial distribution of soil erosion potential danger is evaluated.At last,the paper summarizes that the causes of soil erosion are the local geographical features,large scale migration,and irrational measures of soil and water conservation.