全国土壤侵蚀量估算及其在吸附态氮磷流失量匡算中的应用

Estimation of soil erosion and its application in assessment of the absorbed nitrogen and phosphorus load in China

应用土壤流失方程(USLE),根据我国土壤水力侵蚀分类分级标准,建立了大尺度区域土壤侵蚀量的估算模型;基于GIS技术平台,利用土壤普查数据,构建了全国表层土壤氮磷含量数据库,完成了2000年全国境内水土流失影响下吸附态氮磷的流失量估算.经数据合理性分析验证后得出以下结论:(1)全国因水土流失引发的吸附态氮素和磷素的流失总量分别达到104.22×104t和34.65×104t;(2)长江、珠江和黄河三大流域的吸附态氮、磷流失量之和分别占全国总量的83%和89%,单位面积(1km2)吸附态氮、磷的流失量分别介于6.0×10-4～0.53t和2.1×10-4～0.13t之间;(3)吸附态氮的重点流失区主要分布在长江中上游水土易蚀区、黄河中游沟壑区、西辽河上游区、珠江流域红水河、西江等上游区以及怒江、澜沧江下游区.

Based on the principle of the universal soil loss equation （ USLE）, a model was developed for estimating the loss load of soil erosion over a large scale. Applying GIS and soil data of the second soil survey in China, the loss loads of absorbed nitrogen and phosphorus were simulated and estimated for the year of 2000. There were three significant results. （1） The national loss loads of absorbed nitrogen and phosphorus were about 1,042,200 tons and 346,500 tons respectively in 2000. （2） The Yangtze River Basin, Zhujiang River Basin and Yellow River Basin together accounted for 83% and 89% of the national absorbed nitrogen and phosphorus loss loads, respectively, Loss loads for absorbed nitrogen and phosphorus from the unit grids （1km^2） ranged from 6.0×10^-4t to 0. 53t and 2.1×10^-4t and 0. 13t. （3） The most polluted areas included the upper and middle reaches of the Yangtze River, the middle reaches of the Yellow River, the upper reaches of West Liaohe River, the upper reaches of the Hongshuihe and Westjiang rivers, and the lower reaches of Nujiang and Lancangjiang rivers.