Responses of Soil Microbial Communities to Abandoned Paddy Fields With Different Fertilization Histories

ABSTRACT The abandonment of cultivated fields notably affects soil characteristics. However, its impact on soil microbial community composition, particularly under different fertilization regimes, remains poorly understood. Therefore, we evaluated the effects of abandoned paddy fields with different fertilization histories (no fertilization, NK, NP, and NPK) on the abundance, composition, and their predicted function of soil bacteria and fungi. Our findings revealed that the abandonment led to a considerable decrease in soil bacterial and fungal biomass. Fertilization history and abandonment each significantly affected on the bacterial community, resulting in increased relative proportions of Acidobacteria and decreased relative proportions of Proteobacteria in the NP and NPK treatments compared to those in the CK and NK treatments. The fungal community only exhibited a notable response to abandonment, with variations in the relative abundance of Ascomycota, Mucoromycota, and Basidiomycota. Canonical correspondence analysis revealed the significant association between soil bacterial community and pH, total phosphorus, and available phosphorus, whereas the pH and NO 3 − –N were key drivers of fungal community variations in abandoned soils. Network analysis indicated that abandonment enhanced the complexity but decreased the stability of the bacterial community, while fungi exhibited the opposite trend. Our findings highlight that changes in bacterial functions caused by residual nutrients, particularly high residual phosphorus, may accelerate soil organic C decomposition. Overall, this study provides a novel insight into the shifts in soil bacterial and fungal communities and their ecological functions after the abandonment of cultivated fields.