Differential Responses of Soil Bacterial Community and Respiration to Plastic Film and Straw Mulching in a Maize Field

Soil respiration (Rs), driven by microbial activity, varied with mulching practices, but the microbial mechanisms behind these differences remain unclear. To address this knowledge gap, a three-year (2019–2021) maize field study was conducted to evaluate three treatments: no mulching (CK), plastic film mulching (PM), and straw mulching (SM). This study assessed the effects of these practices on the alpha diversity and composition of the bacterial community and Rs, and explore the roles of soil abiotic and biotic factors in driving Rs. The results indicated that PM significantly increased bacterial alpha diversity (as indicated by ASVs, Chao1, and Shannon indices) in the early growth stage of maize and decreased the bacterial abundance and Shannon index in the late growth stage, whereas SM increased that. Furthermore, PM and SM significantly altered the bacterial community, with PM enriched Chloroflexi and Firmicutes, while SM promoted Gamaproteobacteria and Bacteroidota. Cumulative Rs under PM varied interannually, increasing in 2019 and 2020 but decreasing by 9.1