Organic and conventional farming systems differentially affect methane-cycling microbial community dynamics in Korean paddy soils

초록

Mitigating methane (CH4) emissions from agriculture is critical for addressing climate change. This study aimed to evaluate the effects of organic (OF) and conventional farming (CF) on the community structure and characteristics of methane-cycling microorganisms (MCM) and their role in CH4 production and oxidation processes. A total of 16 soil samples were collected from paddy fields in Yangpyeong, Gyeonggi Province, in 2022 and five sites in Chungcheong Province in 2023. The microbial community distribution was analyzed using 16S rRNA gene sequencing, targeting the V3-V4 region. The relative abundances of methanogenic archaea (MA) were higher in CF (0.55 +/- 0.27%) than in OF (0.21 +/- 0.15%), and methane-oxidizing bacteria (MOB) were also more abundant in CF (3.61 +/- 0.53%) than in OF (2.89 +/- 1.52%). Permutational multivariate analysis of variance (PERMANOVA) showed that the MA community differed significantly between farming practices (p = 0.007, R & sup2; = 0.124), whereas the MOB community was not significantly different (p = 0.511, R & sup2; = 0.059). Network analysis revealed that methane production and oxidation processes in OF followed more complex multistep pathways than those in CF. This was supported by the higher number of edges in the OF network than in the CF network (OF: 459; CF: 424), a higher average degree (OF: 3.572; CF: 2.975), and a higher network density (OF: 0.014; CF: 0.010). Additionally, interaction patterns within MCM communities varied between farming practices, indicating that the type and management of resources can either stimulate or suppress microbial activity. This study provided valuable foundational insights into MCM communities and CH4 cycling mechanisms in Korean paddy soils and is expected to contribute to the development of sustainable agricultural management strategies for reducing CH4 emissions.

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