Start Date: Sep 30, 2011
End Date: Sep 29, 2016
(a) Conduct laboratory and field experiments to measure the status of soil water in semi arid regions over wetting and/or drying cycles. These experiments will elucidate the interactions between irrigation, water and water vapor movement in soil, and evaporation from soil during irrigation and drainage cycles and as affected by soil heating and solar energy inputs. Several methodologies for measuring soil water content will be tested and compared to gravimetric sampling (e.g. capacitance, TDR, psychometric). Obtain direct measurement of evaporation and sensible heat flux using the eddy covariance method. The information will be used to develop a measurement database, for model testing, and to obtain modeling uncertainty estimates for use in future regional scale salinity and nutrient assessments. (b) Test a newly develop non-isothermal water and solute transport model to elucidate the accuracy of simulated soil water content and evaporation. Compare simulation to field-scale soil water content and evaporation measurements. This research will include measurement of various soil physical properties, evapo-transpiration, heat transfer, energy balances and soil-atmospheric exchanges to characterize the moisture status of soils. Models will be tested and improved models will be developed, where necessary, to enable prediction of soil moisture status from saturated to very dry conditions.