Application of a two‐pool model to soil carbon dynamics under elevated CO2 |
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| Authors: | Kees Jan van Groenigen Jianyang Xia Craig W. Osenberg Yiqi Luo Bruce A. Hungate |
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| Affiliation: | 1. Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA;2. Department of Botany and Microbiology, University of Oklahoma, Norman, OK, USA;3. Tiantong National Forest Ecosystem Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China;4. Odum School of Ecology, University of Georgia, Athens, GA, USA;5. Center for Earth System Sciences, Tsinghua University, Beijing, China;6. Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA |
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| Abstract: | Elevated atmospheric CO2 concentrations increase plant productivity and affect soil microbial communities, with possible consequences for the turnover rate of soil carbon (C) pools and feedbacks to the atmosphere. In a previous analysis (Van Groenigen et al., 2014), we used experimental data to inform a one‐pool model and showed that elevated CO2 increases the decomposition rate of soil organic C, negating the storage potential of soil. However, a two‐pool soil model can potentially explain patterns of soil C dynamics without invoking effects of CO2 on decomposition rates. To address this issue, we refit our data to a two‐pool soil C model. We found that CO2 enrichment increases decomposition rates of both fast and slow C pools. In addition, elevated CO2 decreased the carbon use efficiency of soil microbes (CUE), thereby further reducing soil C storage. These findings are consistent with numerous empirical studies and corroborate the results from our previous analysis. To facilitate understanding of C dynamics, we suggest that empirical and theoretical studies incorporate multiple soil C pools with potentially variable decomposition rates. |
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| Keywords: | carbon cycle data assimilation data‐model fusion priming soil carbon model |
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