GIS支持下三峡库区典型小流域土壤养分流失量预测

土壤养分流失是农田非点源污染的主要形式。以长江三峡库区典型小流域为研究区域 ,根据土壤养分流失规律与土壤侵蚀量预测结果 ,以及表土中养分含量 ,像元土壤侵蚀量和泥沙对养分的富集比 ,建立了可与 GIS结合的侵蚀泥沙携带养分量预测模式。运算结果显示 ,小流域有机质、氮、磷、钾流失总量分别为 5 0 9.8,47.1,14.6 ,1137.4t,平均 30 .5 ,2 .8,0 .9,6 8.1t/ km2。根据正常施肥水平及有机质累积率草拟的土壤养分流失分级标准来判断 ,三峡库区小流域养分流失量 ,以严重流失占的比例较大。

Prediction on Soil Nutrients Losses at Typical Small Wate rshed of Three Gorges Area with GIS

Soil nutrients loss is the main way of non point pollution from farmland. Taking a typical small watershed of three gorges area as an example, this paper considered the soil nutrients loss character and the predicted amount of soil loss of a pixel, and introduced a nutrient prediction equation.Integrated GIS and the equation, amount of nutrients loss were predicted. The results showed that organic matter, total nitrogen, phosphorus and potassium average annual loss are respectively 30.5, 2.8, 0.9, 68.1 t/km 2. Using average amount of fertilizer application and organic matter accumulate rate to judge nutrients loss risk degree, we found that most nutrients losses are serious in the watershed. The its amount is over half of fertilizer application.