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United States Department of Agriculture

Agricultural Research Service

Title: Field Measurement of the Mobile/immobile Solute Exchange Coefficient and the Mobile Water Content

Authors
item Casey, Frank - IOWA STATE UNIVERSITY
item Logsdon, Sally
item Horton, Robert - IOWA STATE UNIVERSITY
item Jaynes, Dan

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.

Last Modified: 7/31/2014
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