Methane and Nitrous Oxide Emissions Reduced Following Conversion of Rice Paddies to Inland Crab–Fish Aquaculture in Southeast China

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• 作者：Shuwei Liu ; Zhiqiang Hu ; Shuang Wu ; Shuqing Li ; Zhaofu Li ; Jianwen Zou
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：January 19, 2016
• 年：2016
• 卷：50
• 期：2
• 页码：633-642
• 全文大小：517K
• ISSN：1520-5851

文摘

Aquaculture is an important source of atmospheric methane (CH₄) and nitrous oxide (N₂O), while few direct flux measurements are available for their regional and global source strength estimates. A parallel field experiment was performed to measure annual CH₄ and N₂O fluxes from rice paddies and rice paddy-converted inland crab–fish aquaculture wetlands in southeast China. Besides N₂O fluxes dependent on water/sediment mineral N and CH₄ fluxes related to water chemical oxygen demand, both CH₄ and N₂O fluxes from aquaculture were related to water/sediment temperature, sediment dissolved organic carbon, and water dissolved oxygen concentration. Annual CH₄ and N₂O fluxes from inland aquaculture averaged 0.37 mg m^–2 h^–1 and 48.1 μg m^–2 h^–1, yielding 32.57 kg ha^–1 and 2.69 kg N₂O–N ha^–1, respectively. The conversion of rice paddies to aquaculture significantly reduced CH₄ and N₂O emissions by 48% and 56%, respectively. The emission factor for N₂O was estimated to be 0.66% of total N input in the feed or 1.64 g N₂O–N kg^–1 aquaculture production in aquaculture. The conversion of rice paddies to inland aquaculture would benefit for reconciling greenhouse gas mitigation and agricultural income increase as far as global warming potentials and net ecosystem economic profits are of concomitant concern. Some agricultural practices such as better aeration and feeding, and fallow season dredging would help to lower CH₄ and N₂O emissions from inland aquaculture. More field measurements from inland aquaculture are highly needed to gain an insight into national and global accounting of CH₄ and N₂O emissions.