水生植物对农田排水沟渠氮磷迁移生态阻控效果比较研究

以亚热带红壤小流域为研究区域,选取2 m底宽、1 m深的小型农田排水沟渠,种植美人蕉(Canna indica)、狐尾藻(Myriophyllum spicatum)、黑三棱(Sparganium stoloniferum)、灯心草(Juncus effusus)、铜钱草(Hydrocotyle vulgaris)、水芹菜(Oenanthejavanica)等6种多年生水生植物,研究了农业面源污染的生态阻控技术措施及其效果。结果表明,6种水生植物的生态阻控效果差异显著(P<0.01),其生物量变化范围为0.58kg/m2～2.32kg/m2,其中以美人蕉为最大,水芹菜到夏季后进入休眠期,其生物量最低。植物体地上部N、P含量(干基)变化范围分别为N 8.06 g/kg～16.39g/kg和P 1.34 g/kg～3.82 g/kg,地下部分N、P含量变化范围分别为N 5.83 g/kg～10.80 g/kg和P 1.34 g/kg～3.35 g/kg。从生态拦截效果来看,以美人蕉对N的富集能力最强,达到23.90 g/m2,而黑三棱对P的富集能力最强(4.04 g/m2)。总的来讲,美人蕉和黑三棱在试验区具有明显的N、P生态拦截优势,其地上植株还可用作草食性动物的饲料,或者生物质覆盖还田,实现N、P资源循环利用与环境保护的有机结合。

Study on Comparison of Different Aquatic Plant on Nitrogen and Phosphorus Ecological Control Measures in Drainage Ditch of Farmland in Southern China

A small red soil catchments in subtropical region or southern China was selected as a study area.Six typical perennial aquatic plant species,including Canna indica,Myriophyllum spicatum,Sparganium stoloniferum,Juncus effusus,Hydrocotyle vulgaris and Oenanthe javanica were selected and planted in a small drainage ditch(2.0 m wide×1.0 mdepth).The results showed that,the effects of ecological control were significantly different(P<0.01) among the 6 species.The total biomass ranged from 0.58kg/m2 to 2.32 kg/m2,in which C.indica had the greatest one,but O.javanica had the lowest one associated with its dormancy period in summer.The N and P contents(dry-based) in the biomass ranged from 8.06 g N/kg to 16.39 g N/kg,and from 1.34 g P/kg to 3.82 g P/kg,respectively,for aboveground part,and from 5.83 g N/kg to 10.80g N/kg and 1.34 g P/kg～3.35 g P/kg for underground part.Compared with other plant species,C.indica had the highest enrichment capability(23.90g/m2) for N while S.stoloniferum had the highest enrichment capability(4.04 g/m2) for P.We concluded that C.indica and S.stoloniferum have obvious advantages for N and P enrichment in the local ecological interception.The biomass can also be used as the forage for herbivore breeding or biomass incorporation to upland for the purpose of nutrient recycling and environmental protection.