长江中游地下水水位变化对氮输出的影响研究

河岸带地下水水位的变化将使河岸带土壤、水文条件与化学物质迁移之间的关系发生变化.通过模拟长江洪湖河岸带水位变化情况,研究不同地下水水位变化对氮输出的影响,考虑因素为潜水埋深,试验作物为牛精草(Eleusine indica),共设4个处理,研究不同地下水埋深条件下的水质情况.结果表明,不同处理条件下各形态氮的浓度均有不同程度升高,以处理Ⅲ的氨态氮增加最多,为0.30mg/L；处理Ⅱ硝态氮增加最为显著,为0.37mg/L；干湿交替能够引起氨化的突然加强,同时伴随着硝化的骤然加强和NO3--N的暂时积累.相同植被条件下,地下水埋深越浅,NO3--N更易造成地下水环境的污染.在湿润地区,尤其是渔业养殖较多的区域,氨态氮也是地下水污染中的重要贡献者.

Research on effects of different groundwater depth on nitrogen exporting in the middle reaches of Yangtze River

With the Three Gorge Projects was impounded to 175m in 2009, it changes the hydrological condition of downstream of Yangtze River and influence the relation between underground water and river , and then affect the ecological system of region of downstream of Yangtze River. thus changes the migration of sewage in Honghu region. Groundwater depth is one of main factors affecting the migration of sewage pollutants in soil and ground water system. To study the impact of water level changes by impounding in the Yangtze River on the groundwater level in the middle reaches. This paper analyzed the transportation characteristic of nitrate in groundwater under different groundwater depth on soil and groundwater environment, Four types experiments were set in the study by seting two groundwater level and two vegetations. the results showed that the concentration of each kind of nitrogen in groundwater is relative higher, IN types III,NH4+-N increased 0.30 mg• L-1 compared with that of the initial condition.NO3--N increased 0.37 mg• L-1 compared with that of the initial condition in types III,the alternating of dry and humidity can caused ammoniation suddenly, meanwhile, nitritation accumulation temporary. Preliminary, we think that the risk of nitrate polluted groundwater increased in the same vegetation in shallow groundwater level; in moist area ,especially in the region that fishery culture is in large scale, NH4+-N is a big polluted source.