Using soil freezing characteristics to model multi-season soil water dynamics

The soil moisture characteristic (SMC) is a fundamental soil property for simulating soil water dynamics but is difficult and time-consuming to measure. When the soil is frozen, the soil water potential and liquid water content are strongly dependent on temperature. The relation between soil freezing temperatures and liquid water content, termed the soil freezing characteristic (SFC), is related to the SMC. With the widespread use of time-domain reflectometry (TDR) to measure liquid water in frozen soil, simultaneous measurement of soil temperature and liquid water content under frozen conditions enables in situ estimation of the SMC curve through its similarity to the SFC. We investigated the applicability of deducing the SMC curve from in situ measurements of the SFC for simulation of both frozen and unfrozen soil water dynamics. Results suggest that SMC parameters deduced from the SFC may be used for model simulations without a significant loss of accuracy, as compared with model simulations based on pressure plate analyses.