主养草鱼池塘水质指标的变化规律和氮磷收支

Variation Rules of Water Quality and Budget of Nitrogen and Phosphorus in Ponds with Grass Carp as the Dominant Cultured Species

在以草鱼为主要养殖品种的8个标准池塘中分别投喂两种商品饲料，进行为期283d的养殖试验，饲养期间分10次对养殖池塘水质进行检测，起捕后对生长性能和氮、磷收支进行分析。结果表明：随着养殖时间的延长，水体中氨氮、硝态氮、悬浮物含量逐渐增大，9月23日时达到最大值，亚硝态氮、总氮含量在11月1日时达到最大值，之后均显著下降，水体总磷含量持续升高，在试验结束时达到最大值。氨氮、亚硝酸盐氮、硝酸盐氮、总氮、悬浮物和总磷含量在整个养殖期间变化范围分别为0．28～0．92mg／L，0．03-0．13mg／L．0．08—0．75mg／L，2．24—3．92mg／L，29．33～90．67mg／L，0．19～0．63mg／L，养殖结束时含量比养殖前含量分别升高104％-114％，74％～122％，687％-694％，48％～52％，121％～131％和215％～238％。池塘中以鱼体形式产出的氮、磷分别占投入总氮、总磷的35．4％～37．9％和18．9％-20．2％。

An experiment was conducted for a period of 283 days without water exchange （close system） to determine the effects of feeding on the variation rules of water quality and the budget of nitrogen and phosphorus in ponds with grass carp as the dominant cultured species. During the breeding, water quality was measured for 10 times. The results showed that the concentrations of ammonia nitrogen, nitrate nitrogen, suspended solids increased with the extension of feeding time, reached the highest on September 23rd, the concentrations of nitrite nitrogen and total nitrogen had the maximal on November 1 st, after that, significantly dropped. Total phosphorus concentration in water increased with the progress of rearing; at the end of the trial, total phosphorus concentration extend to the maximum. During the whole period of the experiment, ammonia nitrogen varied from 0. 28 to 0. 92 mg/L, nitrite nitrogen from 0. 03 to 0. 13 mg/L, nitrate nitrogen from 0. 08 to 0. 75 mg/L, total nitrogen from 2.24 to 3.92 mg/L, suspended solids from 29.33 to 90. 67 mg/L and total phosphorus from 0. 19 to 0. 63 mg/L. By the end of the experiment, water quality parameters of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen, suspended solids and total phosphorus increased by 104% - 114%, 74% - 122%, 687% -694%, 48% -52%, 121% - 131% and 215% -238%. Within the ponds, 35.4% -37.9% of the input N and 18.9% -20. 2% of the input P were converted to harvested fish, the largest proportion was contained in water and sediment