Zhongxian Li , Ruchun Chen , Haiying Huang

Hier Rice Research Center, Hainan Institute of Tropical Agricultural Resources, Sanya, 572025, Hainan, China
Author    Correspondence author
Molecular Soil Biology, 2026, Vol. 17, No. 1   
Received: 25 Dec., 2025    Accepted: 30 Jan., 2026    Published: 11 Feb., 2026

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Paddy fields in subtropical regions are constantly submerged in water, which can easily lead to a strong reducing environment, making methane-producing bacteria active and increasing methane emissions. However, in the context of increasingly scarce water resources and the continuous emphasis on the "dual carbon" goals, people have begun to pay more attention to alternate wetting and drying (AWD) irrigation, which is believed to save water and potentially reduce emissions. However, the situation is not that simple: some studies combining field experiments, meta-analyses, and multi-omics results have found that the microbial community, key functional genes, and network structure all change under different irrigation patterns. Generally speaking, compared with continuous flooding, AWD can significantly reduce methane emissions and lower the overall warming potential, but sometimes N₂O emissions increase, and the effect is also influenced by factors such as temperature, precipitation, soil organic carbon, and pH. In field practice, the often-mentioned "safe AWD", such as refilling water when the water level drops to about -15 cm, can generally ensure yield while saving water and reducing methane emissions. From a microbial perspective, the periodic changes in water can alter soil Eh and substrate supply, causing the methane-producing related groups and their connections to readjust. These changes often correspond to the variations in gas fluxes and also provide some references for paddy field water management.

Alternate wetting and drying (AWD); Subtropical paddy fields; Microbial co-occurrence network; mcrA/pmoA; Methane production pathway