色季拉山土壤抗蚀性空间差异性分析

Spatial differentiation of soil anti-erodibility in the Sejila Mountain

【目的】分析藏东南高寒气候条件下不同海拔土壤抗蚀性的空间差异,为西藏地区水土流失防治提供理论依据。【方法】以色季拉山土壤为研究对象,分析不同海拔和土层土壤抗蚀性指标的变化特征,采用主成分分析和土壤质量指数法,构建色季拉山土壤抗蚀性综合评价模型,并采用该模型对色季拉山3 200~4 600 m区域土壤抗蚀性强弱进行研究。【结果】在色季拉山海拔3 200~4 600m区域,除团聚体破坏率、毛管孔隙度、非毛管孔隙度、土壤体积质量外,其余土壤抗蚀性指标均随海拔升高总体呈先增大后减小再缓慢增大的趋势。以变异系数评价色季拉山不同土层土壤抗蚀性的空间差异,土壤团粒类指标在海拔4 200~4 600m和3 200~3 600m区域的变异系数分别为23.02%~123.54%和0.85%~19.58%;土壤基本物理指标的变异系数在海拔3 600m区域出现最大值,而变异系数最小值出现在海拔4 200~4 600m区域;有机胶体类指标即有机质含量的变异系数则在海拔4 600m区域出现最小值,为17.86%,在海拔4 200m区域出现最大值,为93.63%。【结论】通过构建土壤抗蚀性综合评价模型,得出色季拉山不同海拔区域土壤综合抗蚀性强弱顺序为3 600m>3 800m>3 400m>4 400m>4 000m>4 600m>3 200m>4 200m。

【Objective】The spatial variations of soil anti-erodibility in alpine-cold region in southeast Tibet were analyzed to provide basis for the prevention and treatment of soil erosion in Tibet.【Method】The changes of soil anti-erodibility index at different altitudes and layers were analyzed and a comprehensive evaluation model was built using the principal component analysis and soil quality index method.The model was then used to evaluate soil anti-erodibility at the elevation of 3 200-4 600 min the Sejila Mountain.【Result】At the altitude of 3 200-4 600 m,except for aggregate destruction rate,non-capillary porosity,capillary and bulk density,other soil anti-erodibility indicators increased first followed by decrease and slow increase.（2）When using variation coefficient to evaluate the spatial differentiation of anti-erodibility in different layers,the variation coefficients of soil aggregate indicator of 4 200-4 600 and 3 200-3 600 were 23.02%-123.54 and 0.85%-19.58%,respectively.The variation coefficients of basic physical indexesof soil peaked at 3 600 m with the lowest at 4 200-4 600 m.The lowest organic colloid index was 17.86%at 4 600 mand the highest was 93.63%at 4 200 m.【Conclusion】Based on the built comprehensive evaluation model,the order of anti-erodibility was 3 600 m〉3 800 m〉3 400 m〉4 400 m〉4 000 m〉4 600 m〉3 200 m〉4 200 m.