Neutral pH induces complex and stable soil microbial networks in agricultural ecosystems

Abstract

Aims

Soil pH critically influences microbial community diversity and structure, characterized by intricate network interactions among community members. However, the precise relationship between soil pH and microbial network complexity and stability remains inadequately explored.

Methods

We analyzed soil samples from 246 agricultural fields spanning 107,200 km² in eastern China, employing a novel moving-window approach to examine key topological attributes of microbial networks across a pH gradient.

Results

Neutral pH (7.0) emerged as a critical threshold for microbial network dynamics. At this pH, networks exhibited maximal complexity, characterized by peak average degree, clustering coefficient, and density. These networks demonstrated superior stability, with enhanced robustness and network cohesion. Conversely, acidic and alkaline conditions corresponded to reduced network complexity and stability, revealing a non-linear pH-network relationship. Distinctive associate clusters at phylum level suggested pH-specific community assemblages.

Conclusion

Neutral soil pH optimizes microbial network complexity and stability. Our findings provide empirical insights into pH-mediated microbial community organization, offering fundamental implications for understanding soil microbial ecology and ecosystem management.