Soil microbial taxonomic traits control the biogeography of carbon use efficiency
Yihe Wang a, Sijin Wang a, Xinran Zhang a, Ziheng Peng a, Shi Chen a, Haibo Pan a, Beibei Chen a, Jiejun Qi a, Chunling Liang a, Jiai Liu a, Chengjie Ren b c, Gehong Wei a, Shuo Jiao
AGRICULTURE ECOSYSTEMS & ENVIRONMENT
DOI：10.1016/j.agee.2026.110341
Abstract
Quantifying the biogeography of soil microbial carbon use efficiency (CUE) is crucial for refining terrestrial carbon cycle models and thereby enhancing predictions of soil carbon stocks. Yet systematic characterization of microbial CUE biogeographic distributions and their microbial drivers at the national scale remains limited. To address this gap, a nationwide soil survey of ∼592 samples from diverse ecosystems across China (including agricultural, forest, grassland, and wetland soils) was conducted to investigate mechanisms driving of microbial CUE at a national scale, with the ¹ ⁸O-H₂O tracer method applied for quantification. Results showed significant variation among ecosystems, with grasslands and forests exhibiting higher CUE than farmlands and wetlands. Further analysis of soil microbiome across the gradient of CUE revealed marked differences in the abundance patterns of bacteria and fungi: the relative abundance of bacteria positively correlated with CUE was significantly higher than that of bacteria negatively correlated with CUE, while the fungal communities exhibited the opposite pattern. Across the studied ecosystems, Acidobacteriota and Proteobacteria dominated in the bacterial communities, whereas Ascomycota was the dominant fungal phylum. The key taxonomic pattern was the contrasting abundance dynamics of microbial taxa positively and negatively correlated with CUE. Elevated bacterial alpha-diversity and community complexity were associated with higher CUE. Additional analysis elucidated the regulatory role of environmental factors in microbial CUE: soil organic carbon, pH, and aridity index modulated CUE by shaping the composition and structure of the bacterial and fungal communities. Collectively, our biogeographic analysis highlights the critical role of microbial taxonomic traits in predicting soil carbon sinks across Chinese ecosystems, offering novel insights into how climate change impacts the carbon-sequestering capacity of soil microbes.