不同拦截植物对小流域农田排水沟渠氮磷消纳效果差异研究

构建生态沟渠消纳水体氮磷是防控农业面源污染的重要措施.为筛选出适应湘北洞庭湖区农区沟渠生长的高富集氮、磷植物,选取津市市毛里湖稻区沟渠作为研究对象,进行生态沟渠拦截试验.于2016~2017年连续监测,系统研究狐尾藻、珍珠梅、海寿花等水生植物及组合对小流域农田排水中氮、磷的去除效果.结果表明:2年观测期(4~8月)内,拦截植物对农田排水总氮、铵态氮、硝态氮及总磷的去除率效应极显著(p<0.01),且去除率具有生长变化趋势.不同拦截植物及组合对总氮、铵态氮、硝态氮及总磷的去除率大小表现为狐尾藻+海寿花>海寿花>珍珠梅>狐尾藻>自然植被.其中,狐尾藻+海寿花组合平均总氮、铵态氮、硝态氮及总磷的去除率2016年分别为53.57%、77.35%、51.74%和61.06%,2017年分别为34.67%、66.53%、39.51%和46.05%.研究区生态沟渠对氮、磷污染物有较好的拦截效应,单种植物以海寿花的水体氮磷消纳效果较好,在此基础上混种狐尾藻,效果更佳.

Removal Rate of Nitrogen and Phosphorus with Different Interception Plant Species in Agriculture Drainage Ditch

Nitrogen and phosphorus in water removed by ecological ditch was one of the important measures to prevent and control agricultural non-point source pollution.In order to screen out higher enrichment plant of nitrogen and phosphorus adapt to the growth in agricultural ditches,the interception test by ecological ditch was conducted to study the removal rate of nitrogen and phosphorus in water for two continuous years of 2016-2017 using agricultural areas of Maoli Lake by aquatic-plant combinations of Myriophyllum verticillatum,Sorbaria sorbifolia,Pontederia cordata and Myriophyllum verticillatum+Pontederia cordata on eutrophic water in small watershed.Results showed that the removal rate of intercept plants had significant effects on total nitrogen,ammonium nitrogen,nitrate nitrogen and total phosphorus in the drainage during observation period for 2 years(April-August).The removal rate per unit area of total nitrogen,ammonium nitrogen,nitrate nitrogen and total phosphorus by different intercept-plant combinations ranked as Myriophyllum verticillatum+Pontederia cordata>Sorbaria sorbifolia>Myriophyllum verticillatum>natural vegetation(Zizania latifolia,Phragmites australis,etc.).The average removal rate per unit area of total nitrogen,ammonium nitrogen,nitrate nitrogen and total phosphorus by the combination of Myriophyllum verticillatum+Pontederia cordata were 53.57%,77.35%,51.74%and 61.06%in 2016,and 34.67%,66.53%,39.51%and 46.05%in 2017,respectively.In conclusion,ecological ditch had good interception effects on the pollutants of nitrogen and phosphorus in the study area.The optimum plant was obtained by Pontederia cordata to remove nitrogen and phosphorus,which combined with Myriophyllum verticillatum appeared better.