HR: 1340h
AN: H23B-1137    [Abstracts]
TI: A Gravimetrically Based Air-Drying Method to Measure Soil Hydraulic Diffusivity
AU: * Tyner, J S
EM: jtyner@utk.edu
AF: John S Tyner, 2506 E. J. Chapman Drive, Knoxville, TN 37996-4531 United States
AU: Wesley, W
EM: wright1@utk.edu
AF: John S Tyner, 2506 E. J. Chapman Drive, Knoxville, TN 37996-4531 United States
AB: A novel technique to measure soil hydraulic diffusivity is described and initial results are presented. The method consists of suspending a wet soil column by two load cells: one for each end of the column. One end of the column is sealed (no flow boundary). A small fan is set to blow air towards the other end of the column, maintaining a dry surface (constant head boundary); thus, the Bruce and Klute boundary conditions are achieved. As the soil column dries, the load cells record the total mass of water evaporated from the column. Additionally, the centroid of the mass of water removed the column can be calculated from the ratio of the change in weight recorded by the two load cells. Previously published algorithms that describe water content along the length of the column during one-dimensional semi-infinite air-drying are optimized such that the resultant water content predictions are consistent with data collected from the load cells. Soil hydraulic diffusivity is then calculated directly from the predicted water contents. The goodness of fit of the predicted water contents is verified using absolute measurements of water content collected with a gamma-ray attenuation system. The method is relatively rapid, and it requires only a small investment for hardware and a minimal amount of technician support to perform.
UR: http://bioengr.ag.utk.edu/jtyner/air-drying.htm
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting