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

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 (1km2) 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.