Nitrogen (N) mineralization, the conversion of organic N into inorganic N, plant available N, is a microbe-mediated processes. However, the roles that specific microbial taxa play in the release of N from cover crop residues during the residual decomposition have been understudied. Pot-based experiments were established in soils incorporated with rye, hairy vetch (HV), and rye+HV cover crop residues. We used DNA-based molecular approaches to quantify and identify bacteria and fungi under each cover crop. Correlation analysis was used to evaluate the roles of specific microbial taxa (i.e., the dominant, influenced, and keystone taxa). Fungal DNA in all cover crop-treated soils peaked within 5–25 days following residue incorporation, which was also the critical period for N mineralization. Additionally, positive links occupied the correlation networks within and between bacteria and fungi in all treatments, suggesting that the microbes synergistically cooperated to degrade the residues and mineralize N. The abundance of decomposers (e.g., Cytophagaceae and Sinobacteraceae) was promoted by HV and rye+HV inputs due to residue lability. The dominant (e.g., Mortierellaceae, Hypomicrobiaceae, and Aspergillaceae), influenced (i.e., Actinosynnemataceae, unidentified SAR202, and Parachlamydiaceae), and keystone (e.g., Clostridiaceae, Cystofilobasidiaceae, and Dolo 23) taxa were positively or negatively correlated with N availability indicators (i.e., soil inorganic N, β-glucosidase enzyme activity, and soil microbial biomass) in each cover crop-treated soil. The results indicate that the taxa were principally responsible for N mineralization from each cover crop input during the residual decomposition period.

氮（N）矿化，即有机氮转化为无机氮，即植物有效氮，是一种微生物介导的过程。然而，特定微生物分类群在残留物分解过程中从覆盖作物残留物中释放 N 的作用尚未得到充分研究。在掺有黑麦、多毛紫云英 (HV) 和黑麦 + HV 覆盖作物残留物的土壤中建立了基于盆栽的实验。我们使用基于 DNA 的分子方法来量化和识别每种覆盖作物下的细菌和真菌。相关分析用于评估特定微生物类群（即优势、受影响和关键类群）的作用。所有覆盖作物处理的土壤中的真菌 DNA 在残留物掺入后的 5-25 天内达到峰值，这也是氮矿化的关键时期。此外，由于残留不稳定，HV 和黑麦+HV 输入促进了噬菌体科和中华杆菌科。优势（例如被孢霉科、低微生物菌科和曲霉科）、受影响（即放线菌科、未鉴定的 SAR202 和副衣藻科）和基石（例如梭状芽孢杆菌科、Cystofilobasidiaceae）和 Dolo 23) 分类群与每个覆盖作物处理土壤中的氮可用性指标（即土壤无机氮、β-葡萄糖苷酶活性和土壤微生物生物量）呈正相关或负相关。结果表明，在残留分解期间，分类群主要负责每种覆盖作物输入的氮矿化。