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研究土壤可蚀性K值有助于宏观判断和定量分析三峡库区土壤侵蚀的特点。依据重庆市和湖北省的第2次土壤普查资料,建立三峡库区各土种的理化性质数据库,并通过三次样条插值方法对不同粒径标准的土壤质地进行转换,然后采用几何平均粒径模型修正公式计算出三峡库区各土种的可蚀性K值,经面积加权平均得到三峡库区11类土壤的可蚀性K值,最后在分类分级基础上,探讨土壤可蚀性K值的分布特征。结果表明:三峡库区土壤可蚀性K值变化于0.007 2~0.019 2 t.hm2.h/(MJ.mm.hm2)之间,其中在0.015 0~0.019 0 t.hm2.h/(MJ.mm.hm2)之间的中高可蚀性和高可蚀性土壤面积占库区总面积的74.49%;三峡库区存在很大的土壤侵蚀风险,国外已有的K值经验算式不能直接照搬,而采用几何平均粒径修正模型对三峡库区土壤可蚀性K值进行估算是可行的。
Studying the value of soil erodibility K helps to judge and quantitatively analyze the characteristics of soil erosion in the Three Gorges Reservoir Area. Based on the second soil census data of Chongqing and Hubei Province, the physical and chemical properties database of soil and soil types in the Three Gorges Reservoir Area was established, and the soil texture with different grain sizes was converted by cubic spline interpolation method. Then, Model correction formula to calculate the erodibility K values of all soil types in the Three Gorges Reservoir Area, obtained by area weighted average 11 types of soil erosion in the Three Gorges Reservoir erodible K value, and finally based on the classification of soil erodibility K value Distribution characteristics. The results showed that the K value of soil erodibility changed from 0.007 2 to 0.019 2 t.hm2.h / (MJ · mm.hm2) in the Three Gorges Reservoir area, and the value of K was between 0.015 0 and 0.019 0 t.hm2.h / (MJ .mm.hm2). The area of high and erodable soil accounts for 74.49% of the total area of the reservoir area. There is a great risk of soil erosion in the Three Gorges reservoir area. The existing empirical formula of K value in foreign countries can not be directly copied However, it is feasible to estimate the soil erodibility K of the Three Gorges Reservoir using the geometric mean particle size correction model.