The influence mechanisms of long-term fertilizations with chemical fertilizer (NPK), a mixture of chemical fertilizer and straw (NPKS), animal manure (AM), and no fertilizer (Ck) on the mineralization of soil organic matter (SOM) in an Ultisol was studied in this study. The cumulative amount and rate of SOM mineralization were stimulated by the examined fertilizations, especially AM treatment. The order Ck ≤ NPK < NPKS < AM was found in the content of the soil total organic carbon, dissolved organic carbon, microbial biomass carbon, and organic carbon in each pool. The proportion of Fe/Al-associated organic carbon in the soil total organic carbon showed the opposite order. The fertilizations, especially the AM and NPKS treatments, increased the relative abundance of Actinobacteria, Proteobacteria and Ascomycota as well as the activity of β-glucosidase and invertase. Structural equation modeling showed that the activity of the hydrolases, the content of labile organic carbon, and the composition and diversity of the microbes were positive factors in controlling SOM mineralization. Among the positive factors, the activity of the hydrolases was the most important, and the content of labile organic carbon was more important than the composition and diversity of the microbes. The information implied that the stimulation of fertilizations on the mineralization of organic matter in Ultisol progressed mainly through the increase in microbial activity.

化肥（NPK），化肥与稻草的混合物（NPKS），动物粪便（AM）和无肥料（Ck）长期施肥对土壤有机质（SOM）矿化的影响机理在这项研究中对Ultisol进行了研究。SOM矿化的累积量和速率受所检查的施肥，尤其是AM处理的刺激。在每个池中土壤总有机碳，溶解有机碳，微生物生物量碳和有机碳的含量中发现Ck≤NPK <NPKS <AM。Fe / Al相关有机碳在土壤总有机碳中的比例显示相反的顺序。施肥，尤其是AM和NPKS处理，增加了放线菌，变形杆菌的相对丰度和子囊菌，以及β-葡萄糖苷酶和转化酶的活性。结构方程模型表明，水解酶的活性，不稳定有机碳的含量以及微生物的组成和多样性是控制SOM矿化的积极因素。在积极因素中，水解酶的活性最重要，而不稳定有机碳的含量比微生物的组成和多样性更重要。信息表明，施肥对Ultisol中有机物矿化的刺激主要是通过增加微生物活性来实现的。