Stimulatory effects of nutrient addition on microbial necromass C formation depend on soil stoichiometry

作者：Yihui Chen, Shutang Liu, Yaping Huang, Qiong Xiao, Xiaorong Zhao, Lei Wu, Wenju Zhang · 发表于：Geoderma · 年份：2025 · DOI：10.1016/j.geoderma.2025.117323 · 被引用次数：18 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil Management and Crop Yield、Soil erosion and sediment transport

Nutrient availability strongly influences soil organic carbon (SOC) accumulation through microbial necromass C (MNC) formation. However, the effects of nutrient addition on regulating MNC formation in soils with distinct stoichiometric ratios are not well understood. Soil samples were collected from a long-term (>40 years) wheat-maize rotation field trial, without and with nutrient management, which exhibited high and low C:nutrient (N and P) ratios, respectively. These soils were incubated with 13 C-labeled glucose (labile C) and nutrients (N and/or P) for 63 days. A greater proportion of labile C was converted into MNC, especially bacterial necromass C, in the low C:nutrient soil (averaging 32 %) than in the high C:nutrient soil (averaging 25 %). In the high C:nutrient soil, N and/or P addition significantly increased newly formed MNC ( 13 C-MNC) by 8–33 %, whereas in the low C:nutrient soil, N and P addition had a marginal and negative effect on 13 C-MNC, respectively. The 13 C-MNC content was negatively correlated with resource stoichiometric ratios (dissolved organic C (DOC):mineral N, microbial C:N imbalance, and DOC:available P), and enzyme activities (β-1,4-glucosidase, leucine amino peptidase, N-acetyl-glucosaminidase, and alkaline phosphatase). These results suggest that the increase in MNC is primarily due to the alleviation of N and P limitations. Furthermore, the 13 C-MNC content was positively correlated with the 13 C-phospholipid fatty acids content, indicating...