Spatiotemporal dynamics of rhizosphere microbial communities under different mulching methods in spring maize.

Introduction: Plastic film mulching is a critical practice in arid agroecosystems, yet its spatiotemporal impacts on the rhizosphere microbiome remain poorly understood. Methods: Here, we investigated how no-mulching (CK), on-film hole sowing (UPM), and film-side planting (FPM) shape the bacterial and fungal communities in the maize rhizosphere across developmental stages (V12 and R6) and soil depths (10, 20, and 30 cm). Results: Concurrently, both mulching strategies increased maize yield relative to CK, with FPM ultimately outperforming UPM (19.05% vs. 6.24%). Amplicon sequencing showed that mulching strongly structured the rhizosphere microbiome with clear spatiotemporal variation. Bacterial and fungal communities exhibited contrasting patterns: bacteria responded mainly in topsoil at V12 and across all depths by R6, whereas fungi responded across the soil profile at V12, with responses weakening with depth at R6. Mulching-particularly UPM-reduced key taxa, including the nitrifying genus Discussion: Although microbial shifts were correlated with yield components, yield increases were likely dominated by the direct physical effects of mulching. Overall, distinct mulching strategies generated divergent rhizosphere trajectories, with FPM potentially offering a more sustainable option for dryland maize production.