Publication Date:
2015-07-17
Description:
Many studies have shown that elevated atmospheric CO 2 concentrations result in increased plant carbon inputs to soil that can accelerate the decomposition of native soil organic matter, an effect known as priming. Consequently, it is important to understand and quantify the priming effect for future predictions of carbon-climate feedbacks. There are potential pitfalls, however, when representing this complex system with a simple, first-order model. Here we show that a multi-pool soil carbon model can match the change in bulk turnover time calculated from overall respiration and carbon stocks (a one-pool approach) at elevated CO 2 , without a change in decomposition rate constants of individual pools (i.e., without priming). Therefore, the priming effect cannot be quantified using a one-pool model alone, and even a two-pool model may be inadequate, depending on effect size as well as the distribution of soil organic carbon and turnover times. In addition to standard measurements of carbon stocks and CO 2 fluxes, we argue that quantifying the fate of new plant inputs requires isotopic tracers and microbial measurements. Our results offer insights into modeling and interpreting priming from observations. This article is protected by copyright. All rights reserved.
Print ISSN:
1354-1013
Electronic ISSN:
1365-2486
Topics:
Biology
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Energy, Environment Protection, Nuclear Power Engineering
,
Geography
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