Modeling Temperature Effects on Decomposition

Temperature strongly affects carbon decomposition making it difficult to apply decay rates determined in one environment to another. After considering a number of approaches, this study recommends modeling decay by using the Arrhenius equation to adjust time. The resulting decay constants are independent of temperature and can therefore be applied to similar materials in other climates. To test the method, parameters developed from a mesophilic mulch decomposition study are applied to a thermophilic compost experiment. A two compartment linear model is used and cases are considered where Q10 values for labile and recalcitrant compartments are uniform and where they differ. In the uniform case, Q10 = 2 is found to be reasonable. Where different Q10 values are allowed, it is found that Q10 = 1 for the labile fraction and Q10 = 3.3 for recalcitrant materials suggesting that labile and recalcitrant materials may respond differently to temperature gradients.