主养草鱼(Ctenopharyngodon idellus)池塘3种混养模式下氮含量的比较

对主养草鱼(Ctenopharyngodon idellus)池塘3种混养模式(模式Ⅰ,草鱼、鲢、鳙、鲫分别为250、35、40、15尾;模式Ⅱ,草鱼、鲢、鳙、匙吻鲟、鲫分别为250、35、20、20、15尾;模式Ⅲ,草鱼、鲢、鲫分别为250、35、15尾)水体和底泥中氮含量进行比较分析。结果表明,模式Ⅰ、Ⅱ、Ⅲ水体TN含量均值分别为1.251、1.001和1.228 mg.L-1,NH4+-N含量均值分别为0.391、0.345和0.319 mg.L-1,NO3--N含量由高到低为模式Ⅰ、Ⅱ和Ⅲ,NO2--N含量由高到低为模式Ⅱ、Ⅰ和Ⅲ。模式Ⅰ、Ⅱ、Ⅲ底泥TN含量均值分别为0.793、0.910和0.963 mg.g-1,NH4+-N含量均值分别为0.005、0.006和0.004 mg.g-1。模式Ⅱ水体TN含量显著低于模式Ⅰ和Ⅲ(P<0.05),底泥中氮营养盐的转化也优于其他2种模式,可见模式Ⅱ最有利于水体中氮营养盐的转化和利用。

Comparison in Nitrogen Content Between Ctenopharyngodon idellus Dominated Fish Ponds Different in Polyculture Model

Nitrogen contents in the waters and sediments collected from three fish ponds dominated with grass carp but slightly different in polyculture model(Model Ⅰ,containing 250 grass carps,35 silver carps,40 bighead carps,and 15 crucian carps;Model Ⅱ,250 grass carps,25 silver carps,20 bighead carps,20 paddlefishes,and 15 crucian carps;Model Ⅲ,250 grass carps,35 silver carps and 15 crucian carps) were analyzed for comparison.Results show that in waters that the mean total nitrogen content of Model Ⅰ,Model Ⅱ,Model Ⅲ was 1.251,1.001 and 1.228 mg·L-1,respectively;and the mean ammonium nitrogen content,0.391,0.345 and 0.319 mg·L-1,respectively;the content of nitrate showed a decreasing order of Model Ⅰ>Model Ⅱ>Model Ⅲ,and the content of nitrite followed a different order,i.e.Model Ⅱ> Model Ⅰ> Model Ⅲ.And in sediments,the mean total nitrogen content of Model Ⅰ,Model Ⅱ and Model Ⅲ was 0.793,0.910 and 0.963 mg·g-1,respectively;and the mean ammonium nitrogen content,0.005,0.006 and 0.004 mg·g-1,respectively.TN in water was significantly lower in Model Ⅱ than in Models Ⅰ and Ⅲ(P<0.05),and the transformation of nitrogen nutrients in the sediment was quicker too.Obviously,Model Ⅱ is the most conducive to transformation and utilization of nitrogen nutrients in the waterbody.