Impacts of Organic Fertilization on the Mineralization of Mine Spoil Organic Carbon in an Alpine Coalmine Field

ABSTRACT This study focused on how to ameliorate coal mine spoil in the Muli mining area via different fertilization treatments using commercial organic fertilizer (COF) and semi‐rotted sheep manure (LSM). Further explored in this study were the impacts of two kinds of organic fertilizers on the coal mine spoil through cultivation experiments in the lab. The results showed that fertilization significantly enhanced the release of CO 2 ( p < 0.05) and also enhanced the enzyme activity related to carbon and nitrogen transformation in all treatments. Partial least squares path modeling analysis further revealed that organic fertilizers mainly affected enzyme activity by regulating the bacterial community, thereby affecting the cumulative priming effect (Cum‐PE). This was the primary pathway via which the organic fertilizers regulated PE. In high‐dosage fertilization treatments, the released CO 2 originated mainly from the fertilizers themselves, indicating that microbial metabolic activities preferentially consumed exogenous organic carbon. This metabolic preference slowed the decomposition of the original organic matter in the coal mine spoil, resulting in a negative PE. Fertilization significantly changed the composition of the bacterial community and also affected the distribution of microbial functional groups, which stimulated the microbial functional potential related to carbon and nitrogen metabolism. The activities and structural changes of these functional communities jointly regulated the direction and intensity of PE. This study systematically elucidated the response of soil organic carbon PE and microbial community to fertilization in mining areas, providing solid theoretical evidences for the amelioration of coal mine spoil in the alpine mining area of Muli.