Straw-Enhanced Soil Bacterial Robustness via Resource-Driven Niche Dynamics in Tea Plantations, South Henan, China

Straw application (SP) is a promising strategy for the improvement of soil fertility, but the biological effects and the mechanisms of its effects on microorganisms remain unclear. The investigation into the tea plantations (CK/S) in southern Henan, China, without/with straw amendment was carried out to assess the effects of SP on the soil bacterial communities using high-throughput sequencing. SP induced the community restructuring of the dominant phyla, e.g., Acidobacteriota, Pseudomonadota, Chloroflexota, with significantly increasing Nitrospirota, Vicinamibacterales and Anaerolineaceae (<i>p</i> < 0.05), while reducing Terriglobales (<i>p</i> < 0.05). These transitions correlated with significantly enhanced <i>α</i>-diversity and <i>β</i>-diversity divergence (<i>p</i> < 0.05). The linear discriminant analysis effect size (LEfSe) results confirmed the significant selective enrichment of nitrogen-cycling taxa (<i>Nitrospira</i>), copiotrophs (<i>Chryseotalea</i>), and anaerobic degraders (Anaerolineaceae), along with the suppression of the oligotrophic lineage (<i>Ellin6067</i>) by SP (<i>p</i> < 0.05). The co-occurrence networks of S had lower topological properties and negative cohesion (<i>p</i> < 0.05), which exhibited intensified simplified complexity and competition. The soil water content (WC) and pH were the main drivers of <i>β</i>-diversity variation and the keystone taxa assembly, as calculated out by distance-based redundancy analysis (dbRDA). This study demonstrates that SP can enhance bacterial network stability and functional redundancy by resource-driven niche partitioning between copiotrophic taxa and nitrogen-cycling guilds through a competition-cooperation equilibrium.