|Casey, Frank - IOWA STATE UNIVERSITY|
|Horton, Robert - IOWA STATE UNIVERSITY|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 1995
Publication Date: N/A
Technical Abstract: A field method for measuring the immobile water fraction and the solute exchange coefficient for use in two domain solute transport models has been developed. Using tension infiltrometers and a sequential application of four conservative anionic tracers, the immobile water fraction and solute exchange coefficient can be estimated. The tracers that were used consist of pentafluorobenzoate o-trifluorobenzoate, o-trifluoromethylbenzoate, 2,6-difluorobenzoate, and 2,3,6-trifluorobenzolate, and were applied to a loam through a tension infiltrometer at a -3 cm pressure head. Forty-eight applications were performed and calculated, and immobile water fractions averaged 0.65 and ranged from 0.39 to 0.95 while calculated solute exchange coefficient values averaged 0.098 h**-1 and ranged from 0.024 to 0.28. These values are within the bounds of earlier reported values by other investigators.