During the decomposition process of soil organic carbon (SOC), microbial products such as microbial necromass and microbial metabolites may form an important stable carbon (C) pool, called microbially derived C, which has different decomposition patterns from plant-derived C. However, current Earth System Models do not simulate this microbially derived C pool separately. Here, we incorporated the microbial necromass pool to the first-order kinetic model and the Michaelis–Menten model, respectively, and validated model behaviors against previous observation data from the decomposition experiments of ¹³C-labeled necromass. Our models showed better performance than existing models and the Michaelis–Menten model was better than the first-order kinetic model. Microbial necromass C was estimated to be 10–27% of total SOC in the study soils by our models and therefore should not be ignored. This study provides a novel modification to process-based models for better simulation of soil organic C under the context of global changes.

在土壤有机碳（SOC）的分解过程中，微生物坏死物质和微生物代谢物等微生物产物可能形成重要的稳定碳（C）库，称为微生物源碳，其分解模式与植物源碳不同。当前的地球系统模型没有单独模拟这种微生物衍生的 C 池。在这里，我们将微生物坏死物质池分别纳入一级动力学模型和 Michaelis-Menten 模型，并根据之前^{13种分解实验的观察数据验证模型行为}C-标记的坏死瘤。我们的模型表现出比现有模型更好的性能，Michaelis-Menten 模型优于一阶动力学模型。我们的模型估计微生物坏死物质 C 占研究土壤中总 SOC 的 10-27%，因此不应忽视。本研究对基于过程的模型进行了新的修改，以便在全球变化的背景下更好地模拟土壤有机碳。