Modeling of Coupled Heat, Water, and Solute Transfer in Wettable and Non-Wettable Soils.

Heat transfer and water movement are coupled near the soil surface.  The effect of soil wettability on coupled heat and water transfer in soil has received limited study.  Furthermore, theory of coupled heat and mass transfer in soil assumes that the soil is perfectly wettable.  The objective of this study is to use a coupled heat and water transfer model to predict transient soil temperature, water content, and electrical conductivity (EC) distributions in wettable and non-wettable closed soil columns.  Two wettable soils (silt loam and sand) and two salinity conditions at two soil wettability conditions (wettable and non-wettable) were used.  The soils were packed into a closed soil column and a 150^oC m^-1 temperature gradient was applied.  Thermo-TDR sensors installed at various depths within the soil columns were used to measure transient soil temperature, soil water content, and EC distributions.  The predicted transient soil temperature, soil water content, and EC distributions will be compared to the observed transient soil temperature, soil water content, and EC distributions obtained from the soil column experiments.