Pulse Brain · Growing Health Evidence Index
Tier 3 — Observational / field trialPeer-reviewed

Unlocking Mechanisms for Soil Organic Matter Accumulation: Carbon Use Efficiency and Microbial Necromass as the Keys

Yang Yang, Anna Gunina, Cheng Huan, Liangxu Liu, Baorong Wang, Yanxing Dou, Yunqiang Wang, Chao Liang, Shaoshan An, Scott X. Chang

Global Change Biology · 2025

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Summary

This large-scale field study along a 900 km climatic transect on the Loess Plateau challenges the predominant reliance on microbial carbon use efficiency as a predictor of bulk soil organic carbon storage. The authors demonstrate that microbial necromass and CUE operate independently on different carbon pools: fungal necromass drives POC accumulation whilst bacterial necromass and CUE regulate mineral-associated carbon formation. The findings suggest that predictive models of SOC dynamics must account for both microbial necromass and CUE as complementary rather than interchangeable drivers.

UK applicability

The climatic optimum identified (5–10°C MAT, 300–500 mm MAP) encompasses much of the UK's cooler regions and western uplands, suggesting the mechanistic insights may be relevant to UK soil management and carbon sequestration strategies. However, direct applicability requires verification under UK soil parent materials, management practices, and grassland/arable systems.

Key measures

Microbial necromass C (amino sugars), microbial carbon use efficiency (18O-H2O approach), particulate organic carbon (POC), mineral-associated organic carbon (MAOC), soil organic carbon (SOC), fungal and bacterial necromass pools

Outcomes reported

The study quantified how microbial necromass (via amino sugar proxies) and microbial carbon use efficiency (CUE) drive formation of particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) pools across contrasting land uses. It demonstrated that POC and MAOC accumulation peaks at mean annual temperatures of 5–10°C and mean annual precipitation of 300–500 mm on the Loess Plateau.

Theme
Farming systems, soils & land use
Subject
Soil biology & microbiology
Study type
Research
Study design
Field trial / observational transect study
Source type
Peer-reviewed study
Status
Published
Geography
China
System type
Mixed farming
DOI
10.1111/gcb.70033
Catalogue ID
SNmojuoqxr-gwxuvb

Topic tags

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