ARS | Publication request: MOBILE-IMMOBILE WATER SOLUTE TRANSPORT MODEL IN UNSATCHEM: FIELD APPLICATION

Submitted to: Agronomy Abstracts
Publication Type: Abstract
Publication Acceptance Date: September 16, 2003
Publication Date: November 3, 2003
Citation: Vaughan, P.J., Shouse, P.J., Suarez, D.L., Van Genuchten, M.T. 2003. Mobile-immobile water solute transport model in UNSATCHEM: Field application. Soil Science Society of America. Paper No. S02-vaughan971694-P.

Technical Abstract: The mobile-immobile water (MIM) model of solute transport can provide an improved representation of solute transport in soils. The Unsatchem model of multicomponent solute transport was upgraded to include the MIM model. The upgrade permits the user to choose between the standard uniform flow model and the MIM model. The MIM model was tested for 45 locations within a 65 ha field in the San Joaquin Valley. Soil sampling at six depths (0-1.8 m) was done at all locations at five different sampling periods starting in November, 1995 and ending in November, 1997. Chloride transport was calculated for both standard uniform flow (UFM) and MIM models. The MIM model parameters, omega, the transfer coefficient, and thetaim, the immobile water content, were varied systematically to determine their influence on the match between the model results and measured resident chloride concentrations. The MIM model performed better than UFM with the best match occurring for the highest thetaim and 10^-4<=omega<=10^-3.