| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Dep. of Agricultural Sciences, Saga Univ., Saga 840, Japan
U.S. Salinity Lab., 450 West Big Spring Road, Riverside, CA 92507-4617
*Corresponding author (fleij{at}ussl.ars.usda.gov).
ABSTRACT
Field-scale solute transport is typically difficult to model due to the complexity and heterogeneity of flow and transport in natural soils. The stream tube model attempts to stochastically describe transport across the field for relatively short travel distances by viewing the field as a series of independent vertical soil columns. This study investigates the stream tube model with the chemical equilibrium and nonequilibrium convection-dispersion equation (CDE) for local-scale transport. A bivarlate (joint) lognormal probability density function was used for three pairs of random transport parameters: (i) the dispersion coefficient, D, and the pore-water velocity, v; (ii) the distribution coefficient for linear adsorption, Kd, and v; and (iii) the first-order rate coefficient for nonequilibrium adsorption, 
, and v. Expressions for travel time moments as a rsult of a Dirac input were derived to characterize field-scale transport according to the stream tube model. The mean breakthrough time for the field-scale flux-averaged concentration, 
f, was found to be identical to that for the deterministic CDE. Variability in D has generally a minor effect on solute spreading compared with variability in v. Spreading of reactive solutes increased for negatively correlated v and Kd, even if the variability in Kd was relatively small, while nonequilibrium adsorption further increased spreading. If was variable, a negative correlation between v and enhanced the skewness of the breakthrough curve for f while spreading was independent of the correlation between and v.
Contribution from the USDA-ARS Salinity Laboratory.
Received for publication July 28, 1994.
This article has been cited by other articles:
|
|
 |
|
  G. Schoups and J. W. Hopmans Evaluation of Model Complexity and Input Uncertainty of Field-Scale Water Flow and Salt Transport Vadose Zone J., August 24, 2006; 5(3): 951 - 962. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. L. Corwin, J. Hopmans, and G. H. de Rooij From Field- to Landscape-Scale Vadose Zone Processes: Scale Issues, Modeling, and Monitoring Vadose Zone J., March 8, 2006; 5(1): 129 - 139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Vanderborght, R. Kasteel, and H. Vereecken Stochastic Continuum Transport Equations for Field-Scale Solute Transport: Overview of Theoretical and Experimental Results Vadose Zone J., March 8, 2006; 5(1): 184 - 203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K.-J. S. Kung, M. Hanke, C. S. Helling, E. J. Kladivko, T. J. Gish, T. S. Steenhuis, and D. B. Jaynes Quantifying Pore-Size Spectrum of Macropore-Type Preferential Pathways Soil Sci. Soc. Am. J., June 28, 2005; 69(4): 1196 - 1208. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. C. Si and R. G. Kachanoski Measurement of Local Soil Water Flux during Field Solute Transport Experiments Soil Sci. Soc. Am. J., May 1, 2003; 67(3): 730 - 736. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Schoups, G. Schoups, and J. W. Hopmans Analytical Model for Vadose Zone Solute Transport with Root Water and Solute Uptake Vadose Zone J., August 1, 2002; 1(1): 158 - 171. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. C. Si Spatial and Statistical Similarities of Local Soil Water Fluxes Soil Sci. Soc. Am. J., May 1, 2002; 66(3): 753 - 759. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
