金沙江干热河谷地区是我国生态环境脆弱地区之一 ,土壤退化十分严重。探讨该区土壤退化机理 ,对于有效防治土壤退化 ,尽快恢复生态和合理开发该区有重要意义。着重研究了该区母质类型和特性及对土壤退化的影响。结果表明 :1 该区强烈反差的岩土特性和母质层次组构 ,控制了所发育土壤退化发生的区域分布 ;2 不同岩性母质发育土壤的退化指数 (SDI)差异较大 ,体现了母质岩性对土壤退化的主导作用 ,是土壤退化的关键性因素

The dry and hot valley of Jingsha River is one of fragile ecological environment areas in C hina, where the soil degradation was very serious. Studying the mechanism of soil degradat ion in th is region was import ant f or preventing soil degradation effectively, and recovering the ecosyst em quickly as well as exploit ing hot regions rationally. This paper mainly dealt with the type and properties of parent materials and influence on soil degradation in this region. The result s indicat ed: 1 The great disparities between rocks and soils in properties and among layers association in parent materials cont rolled regional distribution of degraded soils. 2 The big diff erences in values of Soil Degradation Index (SDI) among soils, which developed from bedrocks and parentmaterials, showed that the features of bedrocks and parentmat erials influenced the soil degradation predominantly and was the key factor to soil degradation. Key words: f eatures of parent mat erials; mechanism of soil degradation; dry and hot valley of Jingsha River