|
|
||||||||
a Dep. of Land Resources and Environmental Sciences, Montana State Univ., Bozeman, MT 59717-3120 USA
b Dep. of Soil and Water Science, Univ. of Alexandria, El-Shatby, Egypt
c Dep. of Soil Science and Soil Geography, Univ. of Bayreuth, Bayreuth 95440, Germany
hlangner{at}montana.edu
Continuous soil pores may act as pathways for preferential flow depending on their size and water status (filled or drained), the latter being largely controlled by the soil matric head (h). The literature contains a wide range of proposed minimal pore sizes that may contribute to preferential flow. The objective of this study was to examine the relationship between h (and corresponding pore sizes) and preferential solute transport in a naturally structured soil. Tracer (3H2O and pentafluorobenzoic acid, [PFBA]) miscible displacement experiments were performed at several h values in intact soil cores (15-cm diameter, 30-cm length) using an apparatus especially suited to maintain constant h while collecting large effluent volumes. To test for the occurrence of preferential flow, observed breakthrough curves (BTCs) were evaluated for physical nonequilibrium (PNE) using a comparison between fitted local equilibrium (LE) and PNE models. Fitting results of the observed BTCs indicated absence of PNE in all solute transport experiments at h
-10 cm. Experiments at h
-5 cm consistently exhibited PNE conditions, indicating the presence of preferential flow. These results suggest that soil pores with effective radii of 150 µm and smaller (water-filled at h = -10 cm) do not contribute to preferential flow. Observed pore water velocities were not indicative of the presence or absence of preferential flow conditions. Continuous measurements of soil water content (
) using time domain reflectometry (TDR) revealed that at h = -10 cm, <2% of the soil volume (15% of
at saturation) had drained.
Abbreviations: ADE, advectiondispersion equation BTC, breakthrough curve LE, local equilibrium PFBA, pentafluorobenzoic acid PNE, physical nonequilibrium PVC, polyvinyl chloride TDR, time domain reflectometry
This article has been cited by other articles:
![]() |
T. G. Poulsen, P. Moldrup, L. W. de Jonge, and T. Komatsu Colloid and Bromide Transport in Undisturbed Soil Columns: Application of Two-Region Model Vadose Zone J., May 26, 2006; 5(2): 649 - 656. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Levin, J. S. Herman, G. M. Hornberger, and J. E. Saiers Colloid Mobilization from a Variably Saturated, Intact Soil Core Vadose Zone J., April 27, 2006; 5(2): 564 - 569. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Schelde, L. W. de Jonge, C. Kjaergaard, M. Laegdsmand, and G. H. Rubaek Effects of Manure Application and Plowing on Transport of Colloids and Phosphorus to Tile Drains Vadose Zone J., March 8, 2006; 5(1): 445 - 458. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. S. Das, J. M. Wraith, G. J. Kluitenberg, H. M. Langner, P. J. Shouse, and W. P. Inskeep Evaluation of Mass Recovery Impacts on Transport Parameters Using Least-Squares Optimization and Moment Analysis Soil Sci. Soc. Am. J., June 28, 2005; 69(4): 1209 - 1216. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Kjaergaard, T. G. Poulsen, P. Moldrup, and L. W. de Jonge Colloid Mobilization and Transport in Undisturbed Soil Columns. I. Pore Structure Characterization and Tritium Transport Vadose Zone J., May 1, 2004; 3(2): 413 - 423. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. N. Pace, M. N. Pace, M. A. Mayes, P. M. Jardine, T. L. Mehlhorn, J. M. Zachara, and B. N. Bjornstad Quantifying the Effects of Small-Scale Heterogeneities on Flow and Transport in Undisturbed Cores from the Hanford Formation Vadose Zone J., November 1, 2003; 2(4): 664 - 676. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. N. Magesan, I. Vogeler, B. E. Clothier, S. R. Green, and R. Lee Solute Movement through an Allophanic Soil J. Environ. Qual., November 1, 2003; 32(6): 2325 - 2333. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. D. Logsdon, K. E. Keller, and T. B. Moorman Measured and Predicted Solute Leaching from Multiple Undisturbed Soil Columns Soil Sci. Soc. Am. J., May 1, 2002; 66(3): 686 - 695. [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 | |||