China National Rice Research Institute, No.359 Tiyuchang Rd., Hangzhou, Zhejiang, 310006, P.R. China.
Environ Sci Pollut Res Int. 2024 Aug;31(40):53437-53446. doi: 10.1007/s11356-024-34772-y. Epub 2024 Aug 27.
Feeding rate is an important factor influencing the carbon and nitrogen input and greenhouse gas emission from aquaculture systems. However, the quantitative relationship between feeding rates and GHG emissions is still poorly understood. In this study, we conducted a laboratory-scale experiment to examine the impact of feeding rate (0%, 2%, 4%, 6%, and 8%) on the CH and NO emissions from a pond rice-fish co-culture system. The results showed that the total amount of CH emission did not significantly differ when the feeding rate was no more than 6%, but increased more than four times when the feeding rate reach to 8%. The amount of NO emission showed a linearly increasing trend with the feeding rate. The emission factors of CH and NO was significantly higher for 8% feeding rate than other feeding rates. The variation of CH emission was primarily attributed to the ratio of mcrA/pmoA in the sediment and the contents of biological oxygen demand (COD) and dissolved oxygen (DO) in the water; and the variation of NO was primarily affected by the available nitrogen in the water and sediment and the content of DO in the water. The overall emission of CH and NO showed an exponential relationship with feeding rate. The total yields of fish and rice did not continuously increase when the feeding rate exceeded 4%. The lowest emission intensity per unit yield was reached at the feeding rate of 2.99%. These results can provide a reference for the determination of low-carbon feeding strategy for pond rice-fish co-culture system.
摄食率是影响水产养殖系统碳氮输入和温室气体排放的重要因素。然而，摄食率与温室气体排放之间的定量关系仍不清楚。本研究通过实验室规模的实验，研究了摄食率（0%、2%、4%、6%和 8%）对池塘稻-鱼共养系统 CH 和 NO 排放的影响。结果表明，摄食率不超过 6%时，CH 排放总量无显著差异，但摄食率达到 8%时增加了四倍以上。NO 排放量随摄食率呈线性增加趋势。8%摄食率的 CH 和 NO 排放因子显著高于其他摄食率。CH 排放的变化主要归因于沉积物中 mcrA/pmoA 的比例以及水中生物需氧量（COD）和溶解氧（DO）的含量；NO 的变化主要受水中和沉积物中有效氮以及水中 DO 含量的影响。CH 和 NO 的总排放量与摄食率呈指数关系。当摄食率超过 4%时，鱼和水稻的总产量不再持续增加。在摄食率为 2.99%时，单位产量的排放强度最低。这些结果可为池塘稻-鱼共养系统低碳摄食策略的确定提供参考。
