Soil quality associated with microbial community characteristics and dominant taxa across different tillage practices

Abstract Despite conservation tillage being a promising strategy to mitigate soil degradation, the intricate role of microbial communities in shaping soil quality over long‐term tillage remains poorly understood. The study aimed to investigate the microbial mechanisms governing the soil quality index (SQI) and maize yield under different tillage practices spanning 13 years, including no‐till without straw retention (NT0), no‐till with straw retention (NTSR), plough tillage with straw retention (PTSR), and rotary tillage with straw retention (RTSR). The findings revealed that NTSR improved the SQI index by 22.4% and 11.3% higher than PTSR and RTSR, respectively, within the 0–10 cm soil layer. This improvement was correlated with an increase in maize yield ( R 2 = 0.39, p < 0.05). PERMANOVA analysis confirmed that both soil depth and tillage practices significantly impacted the composition of microbial communities ( p < 0.05). Furthermore, conservation tillage, compared to PTSR and RTSR, increased the abundance of arbuscular mycorrhizal symbiosis by 78.6%–460.3% but decreased the saprophytic fungal abundance by 27.5%–28.3%. Soil quality was notably influenced by the interaction between bacterial and fungal communities. The presence of bacterial‐dominated Module 2 was associated with decreased soil quality in the 0–10 cm soil depth ( r = −0.47, p < 0.01). This study emphasizes the pivotal role of microbial diversity and dominant taxa in driving soil quality after long‐term conservation tillage practices. Understanding these mechanisms is crucial for establishing farmland management to achieve agricultural and ecological sustainability in the face of climate change and soil degradation challenges.