The role of microbes in hydrological soil health
Soil microbial communities play an important role in regulating soil structure and plant responses to drought, yet the mechanisms linking agricultural management, microbial traits, and hydrological soil health remain poorly understood. In this study, we investigated how microbial communities contribute to soil hydrological properties across agricultural systems in the US Midwest. Soils were collected from 69 maize fields across Illinois, Indiana, and Michigan representing a wide range of management practices. Microbial community composition was characterized using amplicon sequencing of bacterial 16S rRNA genes and fungal ITS regions. These microbial data were integrated with measurements of soil properties including extracellular polymeric substances (EPS), wet aggregate stability, and soil drying rates, as well as greenhouse experiments evaluating plant drought responses. Structural equation modeling was used to evaluate direct and indirect relationships among management practices, microbial communities, and soil and plant outcomes. Results indicate that fungal communities are strongly associated with improved wet aggregate stability and reduced soil drying, whereas EPS-related traits showed weaker relationships with hydrological outcomes. Cover cropping emerged as an important management practice shaping microbial communities linked to improved soil hydrological function. These findings highlight the role of microbial community composition, particularly fungi, in influencing soil structural stability and drought-related processes in agricultural soils. The sequencing data generated in this study provide insights into microbial mechanisms underlying soil health and resilience to water stress.