HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Cote, C.M. Articles by Ross, P.J. Search for Related Content PubMed Articles by Cote, C.M. Articles by Ross, P.J. GeoRef GeoRef Citation Agricola Articles by Cote, C.M. Articles by Ross, P.J.

DIVISION S-1-SOIL PHYSICS

Quantifying the Influence of Intra-Aggregate Concentration Gradients on Solute Transport

^a CSIRO Land and Water, Davies Lab., University Rd., Townsville, Australia

claire.cote{at}tvl.clw.csiro.au

The physical nonequilibrium of solute concentration resulting from preferential flow of soil water has often led to models where the soil is partitioned into two regions: preferential flow paths, where solute transport occurs mainly by advection, and the remaining region, where significant solute transport occurs through diffusive exchange with the flow paths. These two-region models commonly ignore concentration gradients within the regions. Our objective was to develop a simple model to assess the influence of concentration gradients on solute transport and to compare model results with experiments conducted on structured materials. The model calculates the distribution of solutes in a single spherical aggregate surrounded by preferential flow paths and subjected to alternating boundary conditions representing either an exchange of solutes between the two regions (a wet period) or no exchange but redistribution of solutes within the aggregate (a dry period). The key parameter in the model is the aggregate radius, which defines the diffusive time scales. We conducted intermittent leaching experiments on a column of packed porous spheres and on a large (300 mm long by 216 mm diameter) undisturbed field soil core to test the validity of the model and its application to field soils. Alternating wet and dry periods enhanced leaching by up to 20% for this soil, which was consistent with the model's prediction, given a fitted equivalent aggregate radius of 1.8 cm. If similar results are obtained for other soils, use of alternating wet and dry periods could improve management of solutes, for example in salinity control and in soil remediation.

Abbreviations: SSA, Single Spherical Aggregate model • TDR, time domain reflectometry

This article has been cited by other articles:

				S. Eguchi and S. Hasegawa Determination and Characterization of Preferential Water Flow in Unsaturated Subsoil of Andisol Soil Sci. Soc. Am. J., January 25, 2008; 72(2): 320 - 330. [Abstract] [Full Text] [PDF]

				E.-J. Park and A. J. M. Smucker Saturated Hydraulic Conductivity and Porosity within Macroaggregates Modified by Tillage Soil Sci. Soc. Am. J., January 1, 2005; 69(1): 38 - 45. [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]