金沙江干热河谷典型区(云南)退化土壤的结构性与形成机制

The Structure Feature and Formation Mechanism of the Degraded Soil in Dry-Hot Valley Region of the Jinsha River, Yunnan Province,China

云南金沙江干热河谷区是我国典型的土壤退化区域。通过分析土壤机械组成、团聚体及微团聚体组成、孔隙分布状况等指标 ,探讨了土壤结构对土壤退化的影响机制。研究发现 :1.采用分散率、侵蚀率、团聚度、团聚状况、结构体破坏率、受蚀性指数EVA 、孔隙度等量化指标可以较好反映土壤退化程度 ;2 .土壤颗粒分散特性、土壤水稳性团聚体稳定性、土壤孔隙度是土壤结构稳定性评价的三个重要方面 。

In order to find the relationship between soil structure and soil degradation, these indexes including dispersion ratio,erosion ratio,aggregation rate,aggregation state,structure deterioration ratio,erodibility index( E VA ),soil porosity were studied in this paper. The result indicated that: 1.Soil dispersion ratio,erosion ratio, E VA ,aggregation rate and aggregation state ect. can reflect dispersion properities of soil particle. Dispersion ratio,erosion ratio and E VA were positively interrelated to soil degratation, while aggregation rate and aggregation state were negatively interrelated to soil degradation. 2. The ratio of soil structure deterioration,index of unstable aggregate( E LT ), >1mm waterstable aggregate and >0.5mm waterstable aggregate can embody stability of soil waterstable aggregate. The front two factors were positively interrelated to soil degradation, while the back two factors were negatively interrelated to soil degradation. 3.As soil degradation was aggravated, soil antierodibility and soil antidispersion lowered. The degradation of soil in Yuanmou county, Yunnan Province mainly displayed soil antierodibility was lower, which is concerned on soil organic matter and soil clay quantity.