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Wetlands on the world’s most fertile black soil serve as critical yet vulnerable carbon reservoirs, yet their stability is threatened by redox fluctuations intensified by climate change and human activities. However, how cultivation modulates this process and its temperature sensitivity remains poorly understood. Meanwhile, current mainstream carbon cycle models often systematically underestimate actual carbon losses when simulating these dynamics, suggesting that certain key regulatory mechanisms have yet to be incorporated.
Figure 1: Cultivation enhances warming sensitivity of redox-driven carbon pulses in black soils
Here, we integrated field surveys of ten black soils with mechanistic experiments on three contrasting soils along a cultivation gradient, including microbial inoculation, sterilization, radical quenching, and mineral chelation, to demonstrate that rice cultivation fundamentally reshaped the coupled biotic-abiotic process governing temperature sensitivity of carbon pulses under redox fluctuations. We found that rice cultivation enhanced iron-reducing capacity and shifted microbial metabolic pathways toward catabolism, establishing a persistent anaerobic legacy that amplified the warming sensitivity of aerobic carbon pulses. Mechanistically, ferrous mineral-catalyzed oxidation through both direct catalytic oxidation and •OH-mediated pathways, dominated the aerobic pulse in cultivated soils (>44-61% of CO2 yields). This pathway was dependent on anaerobic legacies, including activated mineral catalytic potential and accumulated dissolved organic carbon, and was further intensified by warming. By progressing from macro-scale pattern recognition to micro-scale pathway analysis, this study reveals a previously overlooked mechanism linking microbial functions to mineral catalysis, with important implications for predicting soil carbon stability in redox‑active agricultural landscapes under future climate change.
The findings are published in the Proceedings of the National Academy of Sciences of the United States of America under the title: “Cultivation enhances warming sensitivity of redox-driven carbon pulses in black soils: The overlooked role of anaerobic legacy effects” (Link: https://www.pnas.org/doi/10.1073/pnas.2527881123). The first author is doctoral student Yixuan Wang, with Associate Researcher Chenghao Ge and Professor Dongmei Zhou serving as corresponding authors. Co-authors include Associate Professor Wenxiu Qin (Anhui Agricultural University) and Professor Donald L. Sparks (University of Delaware). This research was supported by the National Natural Science Foundation of China (42130707, 42277018, 22176091) and the Jiangsu Agricultural Science and Technology Innovation Fund (CX(24)1001).
