Reclamation Period and Straw Type Alter Soil Organic Carbon Composition via CAZyme Families in Coal Mine Agroecosystems

Soil organic carbon (SOC) stabilization is crucial for effective ecological restoration in coal‐mining areas, yet the mechanisms underlying straw‐mediated carbon sequestration remain poorly understood. This study investigated how equal‐carbon but different‐mass incorporation of maize (S + M) and wheat (S + W) straw incorporation, across reclamation chronosequences (1, 10, 30 years; R1, R10, R30), associates with SOC composition, microbial communities, and carbohydrate‐active enzymes (CAZymes). Results showed that straw type and its input mass, together with reclamation duration, significantly shaped SOC dynamics. The S + W treatment under long‐term restoration (R30) yielded the highest content of both labile (14.93 g·kg −1 ) and recalcitrant (2.55 g·kg −1 ) SOC. Specifically, S + W preferentially enriched recalcitrant SOC, whereas S + M enhanced labile SOC components. These shifts were associated with distinct microbial community structures and CAZymes profiles. Co‐occurrence network analysis revealed tighter microbial interactions in early restoration (R1). Notably, methyl carbon was identified as the primary driver of community assembly, strongly linked to the abundances of Ascomycota, Chloroflexi, and Firmicutes. Our findings demonstrate that reclamation period and straw type with differential input mass potentially mediate SOC stability via microbial‐mediated pathways, highlighting the importance of targeted straw management, particularly wheat straw in long‐term restoration, for enhancing carbon sequestration in reclaimed mining ecosystems.