Differences in Methanogenic Pathways and Communities in Paddy Soils Under Three Typical Cropping Modes

作者：Wanyu Shen, Yang Ji, Qiong Huang, Xiaoli Zhu, Jing Ma, Guangbin Zhang, Hua Xu · 发表于：Journal of Geophysical Research Biogeosciences · 年份：2023 · DOI：10.1029/2023jg007443 · 被引用次数：7 · 研究领域：Anaerobic Digestion and Biogas Production、Atmospheric and Environmental Gas Dynamics、Methane Hydrates and Related Phenomena

Abstract The methane (CH 4 ) production process in paddy fields varies depending on different cropping modes. However, there is limited knowledge on the changes in anaerobically produced CH 4 isotopic ratios (δ 13 CH 4 ), the methanogenic pathways, and the dominant communities of methanogens in paddy soils under different modes. To address this, we conducted experiments using anaerobic incubation methods, stable carbon isotope fractionation through inhibition studies with fluoromethane, and high‐throughput sequencing. These methods allowed us to measure the CH 4 production potential (MPP), the relative contribution of acetoclastic methanogenesis to CH 4 production ( f ac ), and the composition of the methanogen community in paddy soils under three typical cropping modes: Rice‐Wheat (RW), Rice‐Fallow (RF), and Double‐Rice (DR) in China. The results showed that MPP was 30.7 μg CH 4 g −1 d −1 in DR soil, around 57% and 66% higher than that in RW and RF soils, respectively, possibly due to the lower pH, clay content, and higher abundance of the mcrA gene. Moreover, RF soil had the highest value of produced δ 13 CH 4 (−43.9‰) but the lowest value of produced δ 13 CO 2 (−26.3‰). Based on the carbon isotope fractionation associated with methanogenesis via H 2 /CO 2 reduction (1.049–1.062), the values of f ac estimated in the RF soil (80%–98%) were much higher than that in the RW (39%–60%) and DR soils (52%–75%). This could be supported by the finding showing that Methanosarcina , th...