Modeling Soil Frost Depth under Three Tillage Systems

ABSTRACT A heat flow based model is developed to predict the rate and depth of soil frost development and disappearance under various tillage-residue management systems. The model is compared with observed results under six tillage residue systems consisting of fall plow, fall chisel and no till with and without residue. The model uses constant values for soil water, thermal conductivity for frozen and unfrozen soil and snow, hydraulic conductivity and heat capacity and is driven by daily inputs of air temperature and snow depth. The assumption is made that mean daily air temperatures are reasonable estimates of the mean daily surface temperature of snow or soil. Predicted and observed frost depth values are in good agreement. Thaw depth predictions show the correct trends but do not match observed values.