Drying–rewetting cycles determine maize growth by shifting microbial community assembly and coexistence patterns

Given increasing climate variability, understanding how rhizosphere microbial communities respond to drying–rewetting cycles and how these cycles impact crop growth under different tillage practices is crucial for improving crop resilience and productivity.

We conducted an experiment with 16 pots at the Institute of Soil Science, Chinese Academy of Sciences, using soils from Lishu, China that had undergone long-term (15-year) traditional (CK) and conservation (CT) tillage practices. We investigated the effects of drying–rewetting cycles on the assembly, diversity, and network of rhizosphere soil microbial communities and their relationships with plant growth.

Compared with consistently moist (W) conditions, the plant growth index (PGI, a comprehensive measure of plant health and growth) under drying–rewetting (D) conditions decreased significantly by 74.7–74.9%. Moreover, the PGI under CT was 46.6–48% greater than that under CK. The D conditions significantly increased the stochasticity of the protistan community assembly. Both D and CT conditions are conducive to the formation of complex associations in multitrophic networks. Soil moisture indirectly impacts potential cross-trophic associations and, ultimately, the PGI by influencing protistan community stochasticity and the β-diversity of bacterial communities.

The results highlight the crucial roles of soil microbial community assembly and coexistence patterns in plant growth during drying–rewetting cycles. Such novel insights provide a basis for developing tillage strategies to increase crop resilience under moisture fluctuations. These findings are crucial for future research on synergistic drought resistance in rhizosphere soil micro-food webs and plants under global change.