The accumulation capacity of microbial residues in the rhizosphere increased along an elevation gradient

作者：Shaojun Deng, Qitong Wang, Dungang Wang, Han Yang, Peipei Zhang, Na Li, Xinjun Zhang, Ruihong Wang, Huajun Yin · 发表于：CATENA · 年份：2024 · DOI：10.1016/j.catena.2024.107891 · 被引用次数：22 · 研究领域：Soil Carbon and Nitrogen Dynamics、Peatlands and Wetlands Ecology、Microbial Community Ecology and Physiology

Root activities fuel higher microbial growth and metabolic activity, which may greatly promote the formation efficiency of microbial residues and their contribution to soil organic carbon (SOC) sequestration in the rhizosphere. However, the contribution of microbial residues to SOC accumulation in the rhizosphere across elevation, as well as the associated microbial metabolic traits, remains poorly understood. Here, we investigated the microbial residue C (MRC) concentrations and their contribution to SOC (i.e., microbial C pump (MCP) efficacy) in the rhizosphere and bulk soil along an elevation gradient on the Tibetan Plateau. We further assessed the accumulation capacity of microbial residues in the rhizosphere ( R MCP efficacy ) by calculating the ratio of the MCP efficacy between the rhizosphere and bulk soil, and by analyzing the associated microbial metabolic traits. The results showed that the MCP efficacy in the rhizosphere was significantly higher than in bulk soil across all elevations, suggesting that the rhizosphere exerts a considerable capacity to accumulate microbial residues. Moreover, the R MCP efficacy increased with elevation, which was accompanied by an enhancement in microbial metabolic efficiency (i.e., increased carbon use efficiency and reduced enzyme investment), implying that microbial trait-based strategies shift from a resource acquisition strategy to a high growth yield strategy with elevation. Collectively, our findings underscore the importance ...