汉江水源区生态沟渠对径流氮、磷的生态拦截效应

Effects of Ecological Ditch Interception of Nitrogen and Phosphorus in Water Source Area of Hanjiang River

[目的]研究汉江水源区生态沟渠对径流氮、磷的生态拦截效应,为农业非点源污染的控制提供重要参考和依据。[方法]设置生态沟渠在不同时间对不同断面水体进行监测。[结果]同段沟渠内,侧面外来水对沟渠径流氮浓度变化影响比磷浓度变化明显;径流TN,NO3-N浓度在上游、中游和下游断面变异系数分别达到19.81%~31.88%,9.57%~16.73%和32.14%~42.81%;NH＋4-N和TP在4个断面变异系数在33.33%~88.46%范围内变化;生态沟渠断面之间,水草拦截净化沟渠段氮、磷含量降低幅度在9.52%~31.11%。[结论]沟渠生态拦截对径流氮素净化效果较明显,同时适当布局拦沙工程可以削减磷素流失。

[Objective]Studying the ecological ditch interception for reducing nitrogen and phosphorus in water source area of Hanjiang River in order to provide reference and basis for agricultural non-point source pollution control.[Methods]Ditch water of different sections was monitored at different times of rain events to study the intercept effectiveness of nitrogen and phosphorus.[Results]Nitrogen concentration was more greatly influenced by extraneous water from the ditch side than that of phosphorus at the same section.The variance coefficients of TN and NO3-N concentrations were 19.81% ~42.81%,9.57% ~16.73% and32.14%~42.81% at the upstream,middle and lower section,respectively.The variance coefficients of NH＋4-N and TP were 33.33% ~88.46% at four sections.Aquatic plant interception decreased the nitrogen and phosphorus concentrations by 9.52% ~31.11%.[Conclusion]Ecological ditch can intercept nitrogen obviously.Meanwhile,some sand interception projects should be arranged appropriately for controlling phosphorus loss.