Large‐scale importance of microbial carbon use efficiency and necromass to soil organic carbon

Abstract

Optimal methods for incorporating soil microbial mechanisms of carbon (C) cycling into Earth system models (ESMs) are still under debate. Specifically, whether soil microbial physiology parameters and residual materials are important to soil organic C (SOC) content is still unclear. Here, we explored the effects of biotic and abiotic factors on SOC content based on a survey of soils from 16 locations along a ~4000 km forest transect in eastern China, spanning a wide range of climate, soil conditions, and microbial communities. We found that SOC was highly correlated with soil microbial biomass C (MBC) and amino sugar (AS) concentration, an index of microbial necromass. Microbial C use efficiency (CUE) was significantly related to the variations in SOC along this national‐scale transect. Furthermore, the effect of climatic and edaphic factors on SOC was mainly via their regulation on microbial physiological properties (CUE and MBC). We also found that regression models on explanation of SOC variations with microbial physiological parameters and AS performed better than the models without them. Our results provide the empirical linkages among climate, microbial characteristics, and SOC content at large scale and confirm the necessity of incorporating microbial biomass and necromass pools in ESMs under global change scenarios.

Allometry and Distribution of Nitrogen in Natural Plant Communities of the Tibetan Plateau

“…Finally, the N content of all samples was measured using an elemental analyzer (Vario MAX CN Elemental Analyzer, Elementar, Germany). pH of the soils was determined using a pH meter (Ultrameter II, United States) ( Wang et al, 2021 ).…”

Soil Microbial Community Response to Nitrogen Application on a Swamp Meadow in the Arid Region of Central Asia

“…The soil microbial community is an important biotic component of soil and an important driving force of many soil ecological processes ( Wang et al, 2021 ). Due to the high sensitivity of soil microbes, the increase in N deposition is bound to have a significant impact on the soil microbial community; however, the response to N deposition often differs in different ecosystems, and the relationship between the soil microbial community and soil factors is uncertain ( Xiao et al, 2020 ; He et al, 2021 ).…”

Depth‐dependent drivers of soil microbial necromass carbon across Tibetan alpine grasslands

“…Considering the predominant contribution of microbial necromass C to stable soil C pool, increasing attention has been paid to determinants of soil microbial necromass C. It has been reported that microbial necromass C is regulated by climatic conditions (Ma et al, 2018; Ni, Liao, Tan, Peng, et al, 2020), soil physicochemical properties (Chen et al, 2020; Ni, Liao, Tan, Wang, et al, 2020), as well as microbial properties (Wang et al, 2021). Despite progressive exploration made thus far, our knowledge on this issue remains inadequate since current investigations have primarily focused on the topsoil above 30 cm (e.g., Ma et al, 2018; Liang et al, 2019; Chen et al, 2020), with relatively limited evidence from subsoil.…”