Aridity drives the response of soil total and particulate organic carbon to drought in temperate grasslands and shrublands
Baoku Shi, Manuel Delgado‐Baquerizo, Alan K. Knapp, Melinda D. Smith, Sasha C. Reed, Brooke B. Osborne, Yolima Carrillo, Fernando T. Maestre, Yu Zhu, Anping Chen, Kate Wilkins, Martin C. Holdrege, Andrew Kulmatiski, Catherine Picon‐Cochard, Christiane Roscher, Sally A. Power, Kerry Byrne, Amber C. Churchill, Anke Jentsch, Hugh A. L. Henry, Karen H. Beard, Max A. Schuchardt, Nico Eisenhauer, Rafael Otfinowski, Yann Hautier, Huitao Shen, Yonghui Wang, Zhongwu Wang, Chengliang Wang, Daniela Cusack, Alessandro Petraglia, Michele Carbognani, T’ai G. W. Forte, S. Luke Flory, Pengli Hou, Tao Zhang, Weifeng Gao, Wei Sun
Abstract
The increasing prevalence of drought events in grasslands and shrublands worldwide potentially has impacts on soil organic carbon (SOC). We leveraged the International Drought Experiment to study how SOC, including particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) concentrations, responds to extreme drought treatments (1-in-100-year) for 1 to 5 years at 19 sites worldwide. In more mesic areas (aridity index > 0.65), SOC and POC concentrations decreased by 7.9% (±3.9) and 15.9% (±6.2) with drought, respectively, but there were no impacts on MAOC concentrations. However, drought had no impact on SOC, POC, or MAOC concentrations in drylands (aridity index < 0.65). The response of SOC to drought varied along an aridity gradient, concomitant with interannual precipitation variability and standing SOC concentration gradients. These findings highlight the differing response magnitudes of POC and MAOC concentrations to drought and the key regulating role of aridity.