Measurement of Soil Moisture and Temperature During Surface Drying.

The coupled transport of liquid water, vapor, and energy in the surface soil layer influences a variety of hydrological and ecological process. For instance, it affects pesticides transport and volatilization. Most soil-atmosphere continuum models are based on the work of Philip and de Vries. However, field experiments conducted on moderately dry soils often provide results much different than those predicted by theory. A major limitation to improving theory is inadequate measurement methods and technologies.    This study focus on developing a methodology for independently measuring: (1) evaporation flux, (2) moisture and temperature dynamics in the upper soil, and (3) soil hydraulic properties. Preliminary results collected from laboratory soil columns will be presented.