Incorporating microorganisms as decomposers into models to simulate soil organic matter decomposition

Current models simulating soil organic matter (SOM) are based on the assumption of first order decomposition. The microbial component of soil organic C (SOC) is mainly simulated as a substrate. The contribution of soil microbe to decomposition as a decomposing agent is implicitly included in the rate constant k and does not change throughout the simulation. The temporal and spatial variation in SOM decomposition/dynamics may have been biased by models, and our prediction of SOM response to global change may have been overestimated, due to missing the feedback effect of microbes on SOM decomposition. We suggest a general model, which explicitly incorporates soil microbe as decomposers of SOM. Future studies in both experiment and modelling are necessary for us to understand interactions between soil microbial abundance and activity, the quality and quantity of SOM pool, and the effects of environmental conditions. (c) 2005 Elsevier B.V. All rights reserved.