Estimation and Empirical Analysis of Nitrogen Non-Point Field Pollution in China:IV Trend and Pollution Extent of Different Type Areas

Cases of nitrogen fertilizer non-point field pollution was concluded and analysed in the three types of nitrogen fertilizer non-point pollution,and traits for every type were concluded.Results were as follows:northeast,eastnorth,Qingzang,westnorth,southwest and Sichuan pan section,these sections were non-fertilizer pollution areas;northwest section was potential contaminated area,the fertilizer filter would be severity if the type of irrigation was not improved;Huanghuihai and Jianghuai area have were middle pollution area,for high dosage fertilizer using;Yangtse rive's triangle,south-east highland,south highland had high fertilizer and water using,which belonged to severe pollution area.In the last part of paper,we concluded and outlooked the basically the status quo and development trend of nitrogen pollution.