Yu Jinyuan, Li Jiwei, Wu Jianzhao, Shangguan Zhouping, Deng Lei
State Key Laboratory of Soil and Water Conservation and Desertification Control, College of Soil and Water Conservation Science and Engineering (Institute of Soil and Water Conservation), Northwest A&F University, Yangling, Shaanxi, 712100, China.
State Key Laboratory of Soil and Water Conservation and Desertification Control, College of Soil and Water Conservation Science and Engineering (Institute of Soil and Water Conservation), Northwest A&F University, Yangling, Shaanxi, 712100, China.
J Environ Manage. 2025 Jun;385:125632. doi: 10.1016/j.jenvman.2025.125632. Epub 2025 May 10.
Microbial necromass is a critical source of soil organic carbon (SOC) in terrestrial ecosystems, and the quantity and quality of microbial necromass carbon (MNC) can influence long-term soil carbon sequestration. However, few studies have explored the distribution of soil MNC and its contribution to SOC along the soil profiles across different ecosystems globally. Here, we collected a global dataset (2, 411 samples from 216 papers) of soil MNC at a depth of 0-100 cm depth from wetlands, farmlands, grasslands, and forests. Our findings indicated that the average MNC at 0-30 cm was 2.7 g kg in wetlands, 7.1 g kg in farmlands, 17.2 g kg in grasslands, and 14.6 g kg in forests. The MNC content in deep soils (30-100 cm) was 70 % lower (p < 0.05) than in topsoil (0-30 cm), whereas the contribution of the MNC to the SOC in deep soils (50 %) was higher than in topsoil in forests (32 %). On average, the fungal necromass carbon(FNC) content (7.5 g kg) was almost three times higher than the bacterial necromass carbon (BNC) content (2.8 g kg) in the topsoill. The mean annual temperature played an important role in affecting the MNC by altering soil total nitrogen, soil texture and microbial biomass. These findings are important for understanding SOC formation mechanisms and the crucial role of microbial necromass in global ecosystems.
微生物残体是陆地生态系统中土壤有机碳（SOC）的重要来源，微生物残体碳（MNC）的数量和质量会影响土壤长期碳固存。然而，全球范围内很少有研究探讨不同生态系统土壤剖面中土壤MNC的分布及其对SOC的贡献。在此，我们收集了一个全球数据集（来自216篇论文的2411个样本），这些样本来自湿地、农田、草原和森林0-100厘米深度的土壤MNC。我们的研究结果表明，0-30厘米深度处湿地的平均MNC为2.7克/千克，农田为7.1克/千克，草原为17.2克/千克，森林为14.6克/千克。深层土壤（30-100厘米）中的MNC含量比表层土壤（0-30厘米）低70%（p<0.05），而在森林中，深层土壤中MNC对SOC的贡献（50%）高于表层土壤（32%）。平均而言，表层土壤中真菌残体碳（FNC）含量（7.5克/千克）几乎是细菌残体碳（BNC）含量（2.8克/千克）的三倍。年平均温度通过改变土壤全氮、土壤质地和微生物生物量对MNC产生重要影响。这些发现对于理解SOC形成机制以及微生物残体在全球生态系统中的关键作用具有重要意义。
