工程化循环水养殖池塘的氮磷收支研究

NITROGEN AND PHOSPHORUS BUDGET IN ENGINEERED RECIRCULATING AQUACULTURE POND

  • 摘要: 为了探寻更清洁高效的养殖模式, 研究将淡水池塘循环水养殖系统进行了改良, 对5个月试验周期内池塘水体理化指标和氮磷收支情况进行了分析。结果显示, 池塘水体的理化指标呈波动性变化, 试验结束时总氮、总磷浓度分别为4.85和1.04 mg/L, 总氮浓度符合淡水养殖尾水排放二级标准。饲料和底泥是池塘氮磷输入的主要来源, 分别占池塘氮元素输入量的50.6%和43.7%, 磷元素输入量的49.4%和46.9%; 底泥积累是池塘氮磷输出的主要途径, 分别占池塘氮磷元素输出量的53.3%和78.7%。试验池塘对氮磷的利用率分别为65.2%和16.6%, 其中鲤对氮磷的利用率显著高于其他鱼类(P<0.05), 鲢、鳙对磷的利用率无显著差异(P>0.05)。研究表明, 改良后的池塘循环水养殖系统有效降低了营养负荷, 提高了养殖生物的氮磷利用率, 减轻了养殖尾水对周边环境的影响, 兼顾生态与经济效益, 是一种成本较低且可持续发展的池塘养殖模式。

     

    Abstract: The intensive aquaculture-induced environmental pollution has impeded the sustainable and healthful progression of the aquaculture industry. In order to explore a more sustainable and efficient aquaculture model, we enhanced the circulating aquaculture system in freshwater ponds in this study. The physicochemical indexes and nitrogen and phosphorus budget of ponds were analyzed during the 5-month experiment period. The results showed fluctuating changes in the physicochemical indexes of pond water, with total nitrogen and total phosphorus concentrations measuring 4.85 and 1.04 mg/L, respectively, at the end of the experiment. Notably, the total nitrogen concentrations met the secondary standards for freshwater aquaculture tailwater discharge. Feed and sediment emerged as principal contributors to nitrogen and phosphorus input, accounting for 50.6% and 43.7% of nitrogen input and 49.4% and 46.9% of phosphorus input, respectively. Sediment accumulation emerged as the primary mechanism for nitrogen and phosphorus output in ponds, accounting for 53.3% and 78.7% of nitrogen and phosphorus output, respectively. The nitrogen and phosphorus utilization rates in experimental ponds were determined to be 65.2% and 16.6%, respectively. The utilization rate of nitrogen and phosphorus of carp (Cyprinus carpio) were significantly higher than those of other fish (P<0.05). However, there was no significant difference in the phosphorus utilization rate between silver carp (Hypophythalmichthys molitrix) and bighead carp (Aristichthys nobilis) (P>0.05). The research shows that the enhanced pond circulation aquaculture system can effectively mitigate nutrient load, enhance the nitrogen and phosphorus utilization rate of aquaculture organisms, diminish the impact of aquaculture tailwater on the surrounding environment, and concurrently consider ecological and economic benefits. It represents a low cost, environmentally friendly, and healthful pond aquaculture model.

     

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