中国水蚀区土壤可蚀性K值计算与宏观分布

K Value Calculation of Soil Erodibility of China Water Erosion Areas and Its Macro-Distribution

本研究收集、整理了全国31个省（市、区）1：50万的土壤类型图，经过扫描和数字化处理构建了全国1：50万土壤类型图形数据库，并基于全国第二次土壤普查数据整理出与之相对应的16493个土壤样品理化数据，同时结合实地采样、共享和查阅文献等途径，获取了最新的1065个样点的土壤理化性质数据。采用水力侵蚀区中K值的计算方法获取土种的K值。按土种的面积进行加权归并到土属的K值，再将土属K值链接到分省土壤类型图上，接边处理后形成全国水蚀区土壤可蚀性K值分布图。研究表明：全国水蚀区K值变化范围为0．0004—0．0828t·hm^2·h／（hm^2·MJ·mm），变异系数大，平均K值为0．033t·hm^2·h／（hm2·MJ·mm），呈现出由北向南逐渐减小的趋势。黄土区K值最大，紫色土和红壤区北部的K值居中，最小的分布在青藏高原北侧。该研究成果为我国土壤侵蚀预测与生态环境评价提供了基础数据。

The paper collected soil type maps in 1 ∶ 500 000 scale from 31 provinces( autonomous regions and municipalities). It established 1 ∶ 500 000 scale national soil type maps database after scanning and digital processing,classified the corresponding physicochemical data of 16 493 soil samples based on the data from the second national soil survey in 1980s and obtained the latest soil physicochemical data through the ways of field sampling,data sharing and consulting literatures. It obtained the K values of soil species based on the calculation method of K value of water erosion area and weighted according to the area of soil species and then merged to the soil genus. It linked the K value of each soil genus to the soil type maps of different provinces and completed a national K value of soil erodibility of soil erosion area distribution map after jointing all the edges. The results show that the variation range of K value of the national water erosion area is 0. 000 4 ~ 0. 082 8 t·hm2·h/( hm2·MJ·mm),variation coefficient being great and the mean value is 0. 033 t·hm2·h/( hm2·MJ·mm),showing a decreasing trend from the north to south. In loess area,the K value is the maximum. It is in the middle in the purple soil and the north red soil areas and the minimum distribution is in the north of Qinghai-Tibetan Plateau. The research results have provided basic data to China soil erosion prediction and ecological environment evaluation.