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为研究平原地区都市农业区域地表水非点源氮素的时空分异特征,揭示非点源氮污染对地表水环境的影响,连续监测了上海南汇新场镇果园村地表水中总氮和无机“三氮”(硝态氮、铵态氮和亚硝态氮)的含量.结果表明:①水文期和土地利用类型共同影响地表水中氮素的空间分布.受果园影响的地表水中硝态氮(NN)浓度较高,铵态氮(AN)浓度较低,各监测点氮素浓度在多雨期差异较大,在少雨期差异较小;受居民区和工厂影响的地表水中NN和AN浓度相差不大,各监测点氮素浓度在多雨期和少雨期差异都较大.②冬、夏季风风向可能影响果园村地表水中氮素的空间分布.③春雨期总氮(TN)、NN和AN的空间变异大,梅雨期和冬季少雨期略大于秋雨期和盛夏少雨期;亚硝态氮(SNN)与之相反.④5月溶解性有机氮(DON)是果园区地表水中氮素的主要存在形式,占TN的质量分数达到76.1%;其它季节则以溶解性无机氮(DIN)为主,占TN的质量分数平均达到83.2%.⑤果园区NN的季节变异比居民区大,居民区AN和TN的季节变异比果园区大.
In order to study the spatio-temporal differentiation characteristics of surface water non-point source nitrogen in urban agriculture in plain area and to reveal the impact of non-point source nitrogen pollution on surface water environment, the total nitrogen and inorganic nitrogen in surface water of GuoYuan Village, Xinchang Town, (Nitrate, Ammonium and Nitrite) were studied.The results showed that: (1) The hydrological period and the type of land use together affected the spatial distribution of nitrogen in surface water.The nitrate content in surface water influenced by orchard The concentration of nitrogen (NN) was higher and the concentration of ammonium nitrogen (AN) was lower. The concentrations of nitrogen in each monitoring point varied greatly in rainy season and little in rainy season. The NN and AN in surface water affected by residential area and factory The concentrations of nitrogen in the monitoring sites were different in the rainy and dry periods.②The winter and summer monsoon wind direction may affect the spatial distribution of nitrogen in the surface water of the orchard village.③The distribution of total nitrogen (TN), NN And AN had a large spatial variability, while the rainy periods in the rainy season and winter were slightly larger than those in the autumn and midsummer; the nitrite nitrogen (SNN) was the opposite. ④The soluble organic nitrogen (DON) in May was the highest in the surface water of the orchard The main form of existence, accounting for TN mass fraction of 76.1%; other seasons then The content of TN was 83.2% on average with soluble inorganic nitrogen (DIN) .⑤The seasonal variation of NN in orchard was larger than that in residential area, and the seasonal variation of AN and TN in residential area was larger than that in orchard.