Research progress on non-point source pollution of nitrogen in agro-ecosystem

Non-point source (NPS) pollution caused by nitrogen from agro-ecosystem was a serious threat to water environment. Non-point source pollution of nitrogen in agro-ecosystem was reviewed in this paper on its transferring characteristics, releasing routes and pollution styles, especially on the process of diffusion and movement mechanisms of NH4+-N and NO3--N between soil and water interface. Methods of NPS nitrogen load calculation and assessment index were summarized. Meanwhile, some comments on current development of pollution load models with rations were given;At last, control measures of NPS pollution were introduced and some suggestions were put forward so as to promote further research and control of NPS pollution.