空心菜浮床栽培对集约化养殖鱼塘水质的影响

Effect of Ipomoea aquatica Cultivation on Artificial Floating Rafts on Water Quality of Intensive Aquaculture Ponds

以叶绿素a(Chla)、TN、NH4+-N、NO2-N、NO3-N、TP、PO43-P、CODMn等为主要水质指标研究浮床栽培空心菜对集约化养殖鱼塘的净化作用。结果表明,通过4次收获,空心菜产量可达69618.0～73161.6kg.hm-2;空心菜覆盖率为10%和20%处理组通过收获空心菜直接从1hm2养殖池塘中移出的TN分别为27.51、52.35kg,TP分别为2.83、5.39kg。在相同监测时间下,Chla、TN、NH4+-N、NO2-N、NO3-N、TP、PO43-P、CODMn等各项水质指标按对照组、10%处理组、20%处理组的顺序均呈逐渐降低趋势;其中20%处理组对Chla、TN、NH4+-N、NO2-N、NO3-N、TP、PO43-P、CODMn的去除率分别为15.16%～49.02%、9.04%～36.56%、19.23%～46.34%、22.76%～47.74%、13.33%～56.52%、33.33%～45.10%、27.27%～48.15%、3.13%～19.05%。与对照塘相比,处理塘鱼类成活率明显提高,说明在主养鱼为鲫鱼的苗种养殖池塘中采用浮床栽培空心菜能够促进水体物质循环,加强水体自净功能,将空心菜的覆盖率确定为20%具有实用价值。

Effects of lpomoea aquatica cultivation on artificial floating rafts on water quality of intensive aquaculture ponds were studied using total phosphorus （TP）, total nitrogen （TN）, orthuphosphate phosphorus （PO4^3--P）, nitrate nitrogen （NO3^--N） , nitrite nitrogen （NO2^--N） , ammonium nitrogen （NH4^＋-N） , CODMn and chlorophyll-a （Chl a） as main water quality indexes, and its mechanism of purifying the water was explored in an experiment. Results show that the yield of Ipomoea aquatica, harvested four times, reached as high as 69 618.0 - 73 161.6 kg · hm^-2. In Treatments 10% and 20% （refers to coverage of the pond by Ipomoea aquatica） 27.51 and 52.35 kg · hm^-2 of TN and 2.83 and 5.39 kg · hm^-2 of TP were, respectively, removed with the harvest of Ipomoea aquatica. In terms of the water quality indexes, Chl a, TN, NH4^＋-N, NO2^--N, NO3^- -N, TP, PO4^3- -P, and CODMn, the three treatments followed a decreasing order of CK 〉 Treatment 10% 〉 Treatment 20%. And the removal rate of Chl a, TN, NH4^＋-N, NO2^- -N, NO^3- -N, TP, PO4^3- -P, and CODMn in Treatment 20% varied in the range from 15.16% to 49.02% , from 9.04% to 36.56% , from 19.23% to 46. 34%, from 22.76% to 47.74%, from 13.33% to 56.52%, from 33.33% to 45.10%, from 27. 27% to 48. 15%, and from 3.13% to 19. 05% , respectively. Fish survival rates in the treatments improved significantly as is compared with that in the control. So it was obvious that in ponds rearing fries of crucians, bighead carps and grass carps, cultivating lpomoea aquatica on artificial floating rafts could accelerate water material cycling and strengthen self-purification capability of the water body. And it is advisable to set coverage of the pond by Ipomoea aquatica at 20%.