三峡库区消落带土壤抗蚀性研究

Study on Soil Anti-erodibility for the Water Level-fluctuating Zone in Three Gorges Reservoir Area

2009年三峡大坝蓄水消落带形成后,其原始的生态环境本底状况不复存在,一些重要的生态环境参数,数据可能无法获得。通过对2008年7月在三峡库区消落带不同地段、不同高程(145～175m)取的28个土样进行土壤理化性质分析。从选取的15个土壤抗蚀性指标中经过主成分分析变换后,提取4个主成分因子,能够反映特征根大部分信息(89.39%),分别为土壤水稳性团聚体类、土壤无机胶粒类、团聚类、有机质及水稳性指数4类因子。通过各主成分贡献率作为权重系数得到了三峡库区消落带土壤抗蚀性综合指数计算方程,从而求出土壤抗蚀性综合指数。根据几大类因子和抗蚀性综合指数进行相关分析,发现三峡库区的土壤有机质含量较低(平均15.88g/kg),其胶结物质主要是无机黏粒<0.001mm,与抗蚀性综合指数相关系数为0.629。这说明消落带无机黏粒<0.001mm的含量对土壤抗蚀性能影响较大。

With the formation of water-level-fluctuating zone of the Three Gorges reservoir area in 2009, its original status of the ecological environment will no longer exists, a number of important parameters and data of the ecological environment may not be able to access. Based on the 28 soil samples which were taked from the different lots and different elevation （145-175 m）of the water level-fluctuating zone of the Three Gorges reservoir area in the July 2008,this article analyzed the soil anti-erodibility of 28 soil samples. 15 indexes were used to analyze the soil anti-erodibility by means of PCA and obtained the 4 categories of water-stable aggregate type, inorganic colloid type, aggregate type,and organic and index of soil water-stable type that reflect 83.39% of the information of the eigenvalues. Through the contribution rate of the four principal component factor as the principal component weighting coefficients, soil anti-erodibility comprehensive index calculation equation can be obtaind and PCA comprehensive exponent of anti-erodibility index can be calculated. According to correlation analysis of the several soil anti-erodibility factor and PCA comprehensive exponent of anti-erodibility index, we can discover that the soil organic matter content in the water level-fluctuating zone of the Three Gorges reservoir area is very lower （an average of 15.88 g/kg）, the main cement material is 〈0. 001 mm inorganic clay, its correlation coefficient is 0. 629 with the PCA comprehensive exponent of anti-erod ibility index. This shows that inorganic clay d0. 001 mm content of water-level-fluctuating have great in fluence on soil anti-erodibility.