Divergent mechanisms driving microbial necromass in topsoil and subsoil along an altitudinal gradient on the Loess Plateau

作者：Yuqian Li, Xuyang Wang, Xiaoming Mou, Bin Jia, Jie Lian, Yayi Niu, Xiangwen Gong, Yuqiang Li · 发表于：Geoderma · 年份：2025 · DOI：10.1016/j.geoderma.2025.117311 · 被引用次数：8 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil erosion and sediment transport、Landslides and related hazards

• Soil microbial necromass increased linearly with altitude. • Microbial necromass content was higher in the topsoil than in the subsoil. • The contribution of fungal necromass was more than that of bacterial necromass. • Topsoil microbial necromass was influenced by microbial biomass and stoichiometry. • Subsoil microbial necromass was influenced by climate and soil stoichiometry. Microbial necromass are one of the main sources of soil organic carbon (SOC) in terrestrial ecosystems. However, the characteristics of soil amino sugar accumulation and their contribution to the SOC pools across different altitudinal gradients and the influencing factors need to be further investigated. In this study, alpine grassland (AG), subalpine scrub (SS), alpine scrub (AS), and alpine meadow (AM) were selected along the altitudinal gradient in the Mt. Maxian. Soil amino sugars are used as biological markers for microbial necromass. Soil physical and chemical properties, microbial biomass, amino sugar content, and their contribution to SOC, and the driving factors of these changes were analyzed at the 0–20 cm and 20–40 cm soil layers. The results showed that: SOC, total nitrogen (TN) and total phosphorus (TP) contents significantly increased along the altitude but decreased with soil depth. Soil microbial necromass increased linearly with altitude and the microbial necromass content was higher in the topsoil than in the subsoil. Total microbial necromass of surface and subsoil contributed 40...