<b>Physicochemical protection outweighs microbial carbon use efficiency in regulating soil organic carbon across an aridity gradient</b>

Here, we conducted large–scale soil samplings across a 3,000–km aridity gradient on the Tibetan Plateau to evaluate the role of microbial CUE in shaping SOC.

Our findings indicate that physicochemical protection, rather than microbial CUE, is the primary control on SOC across the aridity gradient. As aridification is projected to intensify on the Tibetan Plateau under future climate change, explicitly incorporating stabilization mechanisms into Earth system models will be critical for improving projections of soil carbon–climate feedback.</p>