The priming effect (PE) induced by fresh carbon inputs plays an important role in soil organic matter (SOM) mineralization. However, how inputs of different chemical composition litters and nitrogen (N) deposition affect the PE and soil microbial community composition and activity remains unclear. This knowledge gap hinders our ability to constrain models and reduce uncertainty in predicting soil carbon stocks. Thus, we conducted a 100-day incubation experiment with additions of three ¹³C-labeled litters and inorganic N to evaluate the effects of plant litter in combination with N additions on SOM mineralization, PE, microbial community composition and activity in a subtropical Cunninghamia lanceolata forest soil. Our results showed that there was no significant difference in SOM mineralization and PE among the three litters when only litters were added. Compared with sole litter addition, the additions of both litter and N increased PE by approximately 11–42% via the ‘microbial stoichiometry decomposition’. In the case of N addition, the responses of PE, biomass of microbial groups and enzyme activities were related to the litter chemical composition. The direction of PE varied over time, and different microbial mechanisms operated at different stages. Moreover, the incorporation of litter-derived carbon into all phospholipid fatty acids in high-lignin litter added treatment was greater than that of other treatments in the late stage, suggesting that microbes were limited by energy. In conclusion, our findings emphasize that different chemical composition litters in combination with N inputs into soil can have a strong effect on soil carbon stocks by stimulating the priming of native SOM mineralization in subtropical forests. Our results also highlight that changes in litter chemical composition, nutrient availability and microbial processes need to be considered from short to long term, which is of great importance to accurately evaluate the variability of the PE under future climate change scenarios.

由新鲜碳输入引起的启动效应 (PE) 在土壤有机质 (SOM) 矿化中起着重要作用。然而，不同化学成分的凋落物和氮 (N) 沉积的输入如何影响 PE 和土壤微生物群落组成和活动仍不清楚。这种知识差距阻碍了我们约束模型和减少预测土壤碳储量的不确定性的能力。因此，我们进行了为期 100 天的孵化实验，添加了三个¹³ C 标记的凋落物和无机 N，以评估植物凋落物与添加 N 相结合对亚热带杉木的SOM 矿化、PE、微生物群落组成和活性的影响森林土壤。我们的结果表明，仅添加凋落物时，3 次凋落物之间的 SOM 矿化和 PE 没有显着差异。与单独添加垫料相比，添加垫料和 N 通过“微生物化学计量分解”增加了大约 11-42% 的 PE。在N添加的情况下，PE响应、微生物群生物量和酶活性与凋落物化学成分有关。PE的方向随着时间的推移而变化，不同的微生物机制在不同的阶段发挥作用。此外，在后期添加高木质素凋落物的处理中，凋落物衍生碳在所有磷脂脂肪酸中的掺入量大于其他处理，表明微生物受到能量的限制。综上所述，我们的研究结果强调，不同化学成分的凋落物与土壤中的氮输入相结合，可以通过刺激亚热带森林中原生 SOM 矿化的启动，对土壤碳储量产生强烈影响。我们的结果还强调，需要从短期到长期考虑凋落物化学成分、养分可用性和微生物过程的变化，这对于准确评估未来气候变化情景下 PE 的变异性非常重要。