Litter decomposition has historically been attributed to soil microbial community at local scale, but which fundamental process directly contributes to carbon release from decomposing litter remains not fully understood. Here we used in situ microcosms to assess the temporal changes in soil microbial biomass, taxonomic composition, alpha and beta diversity, network complexity and carbon-degrading functional genes during litter decomposition of a subtropical dominant species (Castanopsis carlesii) in an older (45-years) and a younger (9-years) evergreen broadleaved forests. The soil phospholipid fatty acids, bacterial and fungal community composition, α-diversity indexes and network topological properties were not changed significantly after short-term litter input when litter was decomposed by approximately 70%. However, the absolute abundance of functional genes involved in the decomposition of starch, pectin, hemicellulose, cellulose, chitin and lignin were up-regulated, and these variations were associated with soil α-1.4-glucosidase, β-glucosidase and cellobiohydrolase activities in contributing to litter carbon release during decomposition. These results suggest that the upregulation of functional genes rather than microbial community composition and diversity controls local-scale litter decomposition by encoding and secreting enzymes in these subtropical forests.

历史上，凋落物分解被归因于局部范围内的土壤微生物群落，但直接导致凋落物分解碳释放的基本过程仍不完全清楚。在这里，我们使用原位微观世界来评估亚热带优势物种（卡氏槠）在较老（45-45）的凋落物分解过程中土壤微生物生物量、分类组成、α和β多样性、网络复杂性和碳降解功能基因的时间变化。年）和较年轻（9年）的常绿阔叶林。短期凋落物输入后，当凋落物分解约70%时，土壤磷脂脂肪酸、细菌和真菌群落组成、α多样性指数和网络拓扑特性没有明显变化。然而，参与淀粉、果胶、半纤维素、纤维素、几丁质和木质素分解的功能基因的绝对丰度上调，这些变化与土壤α-1.4-葡萄糖苷酶、β-葡萄糖苷酶和纤维二糖水解酶活性有关垃圾分解过程中碳的释放。这些结果表明，在这些亚热带森林中，功能基因的上调而不是微生物群落组成和多样性通过编码和分泌酶来控制局部规模的凋落物分解。