浮床种植空心菜对罗非鱼养殖池塘水质的净化效果

Purification effects of floating bed cultivation of water spinach on tilapia aquaculture pond water quality

【目的】分析评价浮床种植空心菜对罗非鱼养殖池塘水质的净化效果,为实现罗非鱼健康养殖和提质增效提供技术支持。【方法】在罗非鱼养殖池塘水面分别设覆盖率为10%、15%、20%和0(对照)的空心菜浮床,从池塘水质指标[溶解氧(DO)、pH、总磷(TP)、总氮(TN)、氨氮(NH4+-N)和亚硝酸盐氮(NO2--N)]、罗非鱼生长指标(体长和体重)、存活率和池塘产量等方面对比分析不同覆盖率空心菜浮床的净化效果及经济效益。【结果】在罗非鱼养殖池塘中搭建空心菜浮床,池塘水体pH基本维持在7.2~8.0,DO浓度维持在7.59~8.12mg/L,透明度维持在45~51cm,水温维持在28.5~32.5℃;空心菜浮床能有效控制池塘水体中的NH4+-N、NO2--N、TN和TP,且浮床覆盖率为20%的控制效果最佳。从试验第30d起对照组罗非鱼的体重和体长均低于各浮床组,即在池塘中设空心菜浮床能促进罗非鱼的生长。对照组罗非鱼存活率(81.10%)显著低于各浮床组(94.90%~96.24%)(P<0.05,下同),各浮床组间的罗非鱼存活率差异不显著(P>0.05,下同)。在罗非鱼养殖产量方面,对照组池塘罗非鱼平均产量为17250.75kg/ha,各浮床组池塘罗非鱼的平均产量为19291.95~19520.00kg/ha,均显著高于对照组,但各浮床组间差异不显著。【结论】在罗非鱼养殖池塘中搭建浮床种植空心菜,能将池塘水体中的氮磷化合物控制在较低水平,减少罗非鱼疾病发生而提高其存活率,同时增加罗非鱼养殖的经济效益和环境效益,且以浮床覆盖率为20%的效果最佳。

【Objective】The aim was to analyze and evaluate the purification effects of floating bed cultivation with water spinach(Ipomoea aquatic)on the water quality of tilapia pond,and provide technical support for the healthy tilapia culture practice and water quality enhancement.【Method】The water spinach floating beds with coverage rates of 10%, 15%,20% and 0(control)were set up on the surface water of tilapia ponds,respectively. The purification effects and economic benefit of the floating beds were compared and analyzed from the aspects of water quality indexes[including the dissolved oxygen(DO),pH,total phosphorus(TP),total nitrogen(TN),ammonia nitrogen(NH4 +-N)and nitrite nitrogen (NO2 --N)],growth indexes(body length and body weight),the survival rate and the total pond yield.【Result】In tilapia culture pond with water spinach floating beds,the water pH,DO concentration,transparency,water temperature of the pond were basically maintained at 7.2-8.0,7.59-8.12 mg/L,45-51 cm and 28.5-32.5 ℃,respectively. The water contents of NH4 +-N,NO2 --N,TN and TP were effectively reduced by the floating bed,and the best effects occurred in the coverage of 20%. From day 30 of the experiment,the body weight and body length of tilapia in the control group were lower than those in different floating bed groups. That was to say,the growth of tilapia could be promoted by floating bed cultivation with water spinach in the tilapia pond. The survival rate of tilapia in the control group(81.10%)was significantly lower than those in the treatment groups(94.90%-96.24%)(P<0.05,the same below),but there was no significant difference in survival rate among the treatment groups(P>0.05,the same below). The average yield of tilapia in the control group was 17250.75 kg/ha,while in the treatment groups,it was 19291.95-19520.00 kg/ha,which was significantly higher than that in the control group. But there was no significant difference among the different treatment groups.【Conclusion】Floating bed cultivation with water spinach in tilapia pond can maintain the nitrogen and phosphorus compounds at a low level, reduce the occurrence of tilapia diseases,improve the survival rate,and increase the economic and environmental benefits of tilapia pond culture. Finally the best effect is obtained when the coverage is 20%.