水培空心菜对养殖池塘水质的影响

Effect of Ipom oea aquatica,as an Ecological Floating Raft,on Water Quality of Aquaculture Ponds

为研究浮床植物对罗非鱼养殖池塘的净化作用，分别在占罗非鱼养殖池塘面积5％、10％和20％的浮床上栽培空心菜，测定池塘 NH＋4-N、NO－2-N、NO－3-N、PO3－4-P、TN、TP、CODMn 等主要水质指标。结果表明，在同样的试验条件下，养殖池塘的各项水质指标依次按对照组、5％处理组、10％处理组、20％处理组顺序逐渐降低；其中以20％处理组对池塘主要水质指标 NH＋4-N、NO－2-N、NO－3-N、PO3－4-P、TN、TP、CODMn 等的去除率最大，分别为42．82％、39．47％、43．8％、64．1％、46．57％、58．75％、7．4％。通过6次空心菜的采收，养殖池塘的空心菜每667 m2产量可达586．86～1434．05 kg；5％处理组、10％处理组、20％处理组通过采收空心菜分别从667 m2养殖池塘中移除 TN 1643．5、2988．2、4015．3 g，分别移除 TP 240．7、437．6、587．9 g；同时处理组池塘罗非鱼的成活率明显高于对照组，由此可见，主养罗非鱼的养殖池塘中浮床栽培空心菜能够很好地净化水质，降低池塘富营养化。因此，认为20％的空心菜浮床覆盖率在罗非鱼养殖过程中具有一定的应用价值。

Effect of the ecological floating rafts on the water quality of intensive aquaculture ponds was studied. Ammonium nitrogen （NH ＋4 -N ）, nitrite nitrogen （NO-2 -N ）, nitrate nitrogen （NO-3 -N ）, orthophosphate phosphorus （PO3 -4 -P）,total nitrogen （TN）,total phosphorus （TP）and CODMn were the major indicators for the determination of water quality.The water purification mechanism was studied as well.In the experiments under otherwise same conditions,three treatments were tested against the control.The pollutant contents in the pond water decreased in the order of control 〉 5% Treatment〉 10% Treatment〉20% Treatment.And,the removal rates on the above listed pollutants resulted from the 20% Treatment,the highest among three,were 42.82%, 39.47%,43.8%,64.1 %,46.57%,58.75% and 7.4%,respectively.The total yield of the 6-harvest floating plants ranged from 586.86 kg to 1 434.06 kg in the 667 m2 pond.For the 5%,10% and 20% treatments, 1 643.5,988.2 and 4 015.3 g per 667 m2 of TN,respectively,and 240.7,437.6 and 587.9 g per 667 m2 of TP, respectively,were removed from the water. Meanwhile,the survival rate of the tilapia raised in the tested aquaculture pond improved significantly with the treatments.It appeared that cultivating Ipom oea aquatica in a tilapia pond could purify the pond water through eutrophication reduction.Specifically,a 20% of the artificial floating raft on a tilapia aquaculture pond could be recommended for implementation.