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Coupled Liquid Water, Water Vapor, and Heat Transport Simulations in an Unsaturated Zone of a Sandy Loam Field

Deb, Sanjit K.; Shukla, Manoj K.; Sharma, Parmodh; Mexal, John G.

doi: 10.1097/SS.0b013e318221f132
Technical Article

Information on the coupled liquid water, water vapor, and heat transport under arable field conditions is still limited, particularly for unsaturated soils of semi-arid and arid regions such as New Mexico. HYDRUS-1D model was applied to evaluate various transport mechanisms associated with temporal variations in water content and soil temperature in the unsaturated zone of a sandy loam furrow-irrigated field located at Leyendecker Plant Science Research Center, Las Cruces, New Mexico. The model was calibrated using measured soil water content and soil temperature at 5-, 10-, 20-, and 50-cm depths during a 19-day period (day of the year [DOY] 85 to DOY 103, 2009) and validated for a 31-day period (DOY 104 to DOY 134, 2009). Measured and optimized soil hydraulic and thermal properties and hourly meteorological data were used in model simulations. HYDRUS-1D simulated water contents and soil temperatures correlated well with the measured data at each depth. The total liquid water flux, composed of isothermal and thermal liquid water flux, dominated the soil water movement during early periods after irrigation, whereas the contribution of total water vapor flux, composed of primarily thermal and much smaller isothermal water vapor flux, increased with increasing soil drying. During the soil drying process, the total liquid flux within 15-cm depth eventually changed to water vapor flux near the surface. The upward total liquid and vapor fluxes decreased from 5 cm, indicating that vapor flux was much higher in the layer near the soil surface. The total vapor flux in this unsaturated soil layer was approximately 10.4% of the total liquid and vapor fluxes during the simulation period.

Department of Plant and Environmental Sciences, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003. Dr. Sanjit K. Deb is corresponding author. E-mail: sanjit@nmsu.edu

Received December 1, 2010.

Accepted for publication April 28, 2011.

Financial Disclosures/Conflicts of Interest: The authors thank the New Mexico State University Agricultural Experiment Station for support. The financial support from the Specialty Crop Research Initiative, USDA-CSREES, and the Rio Grande Basin Initiative is also gratefully acknowledged. The authors report no conflicts of interest.

© 2011 Lippincott Williams & Wilkins, Inc.