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Book: Tomography of Soil-Water-Root Processes
Published by: Soil Science Society of America, American Society of Agronomy, and Crop Science Society of America



  1.  p. 59-71
    SSSA Special Publication 36.
    Tomography of Soil-Water-Root Processes

    S. H. Anderson and J. W. Hopmans (ed.)

    ISBN: 978-0-89118-931-2


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Soil-Core Breakthrough Measured by X-Ray Computed Tomography

  1. R. Lee Peyton,
  2. Stephen H. Anderson,
  3. Clark J. Gantzer,
  4. John W. Wigger,
  5. David J. Heinze and
  6. Hong Wang
  1. Amoco Oil Corporation, Tulsa, Oklahoma
    McLaren/Hart Environmental Engineering, Springfield, Missouri
    Pennsylvania State University, State College, Pennsylvania


Solute travel time in a soil core measured from the usual breakthrough experiment is based on flux-averaged outflow concentrations. For soil cores containing preferential flow paths, the computed travel time and dispersivity are not representative of the majority of the core cross section, nor is this travel time representative of the velocities in the preferential flow paths. X-ray computed tomography was used to measure volume averaged relative concentrations inside the soil core during a breakthrough experiment. These results show velocities 50% less than and dispersivities three to four times as large as those based on flux-averaging for undisturbed silt loam forest cores. Smaller differences resulted for undisturbed loamy sand cores from a cultivated field. Negligible differences resulted for uniformly-packed glass bead cores.

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Copyright © 1994. Copyright © 1994 by the Soil Science Society of Agronomy, Inc., 5585 Guilford Rd., Madison, WI 53711 USA