Rhizosphere microbial community and function activation in rain-fed agricultural areas confer growth advantages to...

The integration of maize stover return and organic alternative cropping under mulching (MSO) represents an efficacious production strategy in the rain-fed agricultural landscapes. In this study, we employed a two-year field experiment coupled with high-throughput sequencing technology to delineate the mechanisms by which rhizosphere microbes facilitate spring maize growth under the MSO strategy, thereby elucidating the microbial contributions to crop productivity. Our findings indicate that MSO serves as a potent conduit for soil carbon sequestration, with a 3.48 % increase in soil organic carbon relative to conventional chemical fertilizer applications. The concentrations of microbial biomass carbon, dissolved organic carbon and readily oxidizable carbon reached their zenith under MSO conditions. Soil carbon components emerged as crucial determinants of both bacterial and fungal communities, influencing their composition and potential functionalities. The alteration of the rhizosphere microbiome mediated by stover return reshaped the carbon and nitrogen cycling pathways within the rhizosphere. In the functional prediction of the rhizosphere, stover incorporation reinforced the two-component system process while mitigating the quorum sensing pathway. Within the elemental cycle prediction model, the processes of methane and CO₂ generation from organic carbon in the rhizosphere carbon cycle, as well as the nitrification and ammonia oxidation processes in the nitrogen cycle, exhibited divergent trends with the introduction of stover. The co-occurrence network analysis revealed a more robust cooperative network among rhizosphere bacteria under the MSO mode compared to fungi. This study offers a novel perspective on the MSO strategy in rain-fed agricultural regions and underscores the pivotal role of key ecological clusters within the rhizosphere in the plant-microbial interaction process.