Microbially mediated mechanisms underlie soil carbon accrual by conservation agriculture under decade-long warming

Abstract

Increasing soil organic carbon (SOC) in croplands by switching from conventional to conservation management may be hampered by stimulated microbial decomposition under warming. Here, we test the interactive effects of agricultural management and warming on SOC persistence and underlying microbial mechanisms in a decade-long controlled experiment on a wheat-maize cropping system. Warming increased SOC content and accelerated fungal community temporal turnover under conservation agriculture (no tillage, chopped crop residue), but not under conventional agriculture (annual tillage, crop residue removed). Microbial carbon use efficiency (CUE) and growth increased linearly over time, with stronger positive warming effects after 5 years under conservation agriculture. According to structural equation models, these increases arose from greater carbon inputs from the crops, which indirectly controlled microbial CUE via changes in fungal communities. As a result, fungal necromass increased from 28 to 53%, emerging as the strongest predictor of SOC content. Collectively, our results demonstrate how management and climatic factors can interact to alter microbial community composition, physiology and functions and, in turn, SOC formation and accrual in croplands.

Microbial life‐history strategies mediate microbial carbon pump efficacy in response to N management depending on stoichiometry of microbial demand

“…The microbial Y-strategy suggests elevated metabolic activity and growth rates, which facilitates the transformation of microbial biomass into necromass (Shao et al, 2021). This is evidenced by a significant positive correlation between microbial Y-strategy and NAC (Figure S8), aligning with prior research demonstrating how microbial growth enhances turnover rates (Tian et al, 2024;Wang et al, 2022). Thus, we conclude that an increase in growth-related strategy likely resulted in the increase in MNC, NAC, and MCP efficacy with increasing N supply in soils with higher initial C (Figure S2; Figure 1).…”

“…How to cite this article: Yang, L., Canarini, A., Zhang, W., Lang, M., Chen, Y., Cui, Z., Kuzyakov, Y., Richter, A., Chen, X., Zhang, F., & Tian, J. (2024)…”

“…In the second mechanism, N addition may increase SOC accumulation via increased belowground plant productivity (Chen et al, 2014;Ni et al, 2022;Xu et al, 2021). Within this second mechanism, emerging insights demonstrate that microbial necromass (microbial remains after cell death) can be viewed as a transformed product of plant-derived C (Feng & Wang, 2023;Tian et al, 2024;Wang, Qu, et al, 2021), which is known as the soil 'microbial carbon pump' (MCP) process (Liang et al, 2017). Microorganisms transform plant-derived C into cellular components or byproducts through anabolism, and their necromass act as persistent components to mediate soil C sequestration (Luo et al, 2022;Zhu et al, 2020).…”

Global Responses of Soil Carbon Dynamics to Microplastic Exposure: A Data Synthesis of Laboratory Studies

“…Soil carbon (C) stocks in terrestrial ecosystems are 3 times larger than the atmospheric C pool, highlighting that even minor changes in soil C could significantly affect atmospheric greenhouse gas concentrations. , MPs pollution is increasingly recognized as a significant environmental concern, with emerging research suggesting its potential influence on soil C dynamics. , Despite numerous individual experiments conducted in recent years to determine the effects of MPs exposure on terrestrial ecosystem C cycles, results remain inconsistent. , Some studies report that MPs increase soil organic C , or neutral responses at lower concentrations of MPs and polyvinyl chloride MPs. , The inconsistency extends to soil respiration, with studies reporting varied effects of MPs exposure. − Past reviews have explored MPs’ impacts on soil ecosystems, but often these investigations have been limited to certain soil C components, contributing to mixed conclusions regarding MPs’ overall influence on soil C dynamics. ,, …”

“…Soil carbon (C) stocks in terrestrial ecosystems are 3 times larger than the atmospheric C pool, highlighting that even minor changes in soil C could significantly affect atmospheric greenhouse gas concentrations. 19 , 20 MPs pollution is increasingly recognized as a significant environmental concern, with emerging research suggesting its potential influence on soil C dynamics. 5 , 8 Despite numerous individual experiments conducted in recent years to determine the effects of MPs exposure on terrestrial ecosystem C cycles, results remain inconsistent.…”