Earthworms modulate soil microbiota to enhance straw degradation and enrich wheat-available nutrients

Earthworms are known for their ability to facilitate straw degradation. This study established a ‘straw–soil–earthworm’ experimental system to explore the effects of earthworms on straw degradation and microbial community dynamics, as well as the impact of degraded straw on soil properties and wheat growth over a 35-d period. Analysis of soil enzyme activities revealed that earthworms significantly enhanced the activities of carboxymethyl cellulase, hemicellulase, and lignin peroxidase in soil, facilitating straw degradation and silicon (Si) release, which subsequently promoted wheat growth. Additionally, high-throughput sequencing analysis and cluster analysis revealed that earthworms significantly influenced microbial community structure, forming a more complex co-occurrence network compared to systems lacking earthworms. Furthermore, enhanced microbial cooperation, particularly between the phyla Proteobacteria and Actinobacteriota, facilitated the transformation of carbon, nitrogen, and Si. The findings of our study underscore the pivotal role of earthworms in shaping soil microbial communities, improving nutrient availability, and promoting wheat growth under natural conditions. • Earthworms enhance soil microbial diversity, boosting nutrient cycling and stability. • Combined straw and earthworm treatments significantly increase Si concentration in soil. • Microbial diversity and co-occurrence networks are more robust in earthworm-treated soils. • Earthworms promote lignocellulose breakdown, boosting enzyme activity and microbial functions. • Microbial community shifts improve C and N cycling, enhancing soil resilience and plant growth.