LINEAR ANALYSIS OF SOIL DECOMPOSITION: INSIGHTS FROM THE CENTURY MODEL

All terrestrial ecosystem models track the decay of soil organic matter (SOM). Most current models use SOM modules that closely follow the Century model, a powerful but complicated model of decomposition and other terrestrial ecosystem processes that was originally designed for temperate grasslands but has since been extended to many terrestrial ecosystems. Using the linearity property of Century’s SOM model, we can simplify it to a set of differential equations with little loss of generality. The simplified model can estimate the equilibrium state of the Century model in closed form, or, using a numerical algorithm, can reproduce its seasonal patterns; it also gives us a framework for making SOM models less complex and producing parsimonious, statistically defensible models of decomposition processes in terrestrial ecosystems.