Limited Effects of Fertilization Practices on Microbial Community Structure and Greenhouse Gas-Related Functional Potential in Paddy and Field Soils

다국어 초록 (Multilingual Abstract)

Fertilization practices are key management factors influencing greenhouse gas (GHG) emissions through soil microbial communities; however, the extent of these effects remains debated. We evaluated the impacts of different fertilization methods—standard, conventional, deep-placement, organic, and non-fertilization—on microbial community structure and GHG-related functional potential in paddy and field soils using 16S rRNA gene-based analysis and functional prediction. β-diversity analysis revealed that microbial communities were clearly separated by land-use type (paddy vs. field), with no significant differences among fertilization methods or soil depths within the same land-use type.
α-diversity indices similarly showed no significant variation across fertilization treatments.
LEfSe analysis identified selective shifts in specific taxa associated with GHG-related processes, including Methanocella, Methylocystis, Nitrospira, and Rhodanobacteraceae.
Despite these taxonomic responses, PICRUSt2-based functional prediction revealed highly consistent metabolic module distributions across fertilization treatments, corroborated by stable patterns of functional genes involved in methanogenesis, methane oxidation, nitrification, and denitrification. These results demonstrate a decoupling between taxonomic shifts and functional potential, suggesting that fertilization practices exert limited influence on GHG-related functional capacity. Instead, functional redundancy within microbial communities, together with land-use type and environmental constraints, appears to maintain functional stability.