Assessing how soil temperature and moisture presentation affects soil organic carbon model parameterization

Soil temperature and moisture are core drivers for soil organic carbon (SOC) decomposition and, thus, are also critical components in SOC models. There is, however, no general agreement on how these impact should be formulated or included in those models. Consequently, it is also uncertain how its representation generally affects SOC model parameterization.

Using the Yasso SOC model and a detailed time series of SOC decomposition at multiple Swedish sites, we tested how different temperature/moisture aspects impacted the model fitting. With temperature, the results were more improved by correctly including the annual temperature cycle, regardless of the model timestep, than by the chosen formulation. With moisture, in turn, the formulation affected the fit more than including the annual cycle. Including both soil temperature and moisture annual cycles, however, reduced the ability to accurately fit the model to chosen sites.