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 Amente, G. Articles by Reece, C. F. Search for Related Content PubMed Articles by Amente, G. Articles by Reece, C. F. GeoRef GeoRef Citation Agricola Articles by Amente, G. Articles by Reece, C. F.

DIVISION S-1-SOIL PHYSICS

Estimation of Soil Solution Electrical Conductivity from Bulk Soil Electrical Conductivity in Sandy Soils

Univ. of Minnesota, Dep. of Soil, Water, and Climate, St. Paul, MN 55108 USA

jbaker{at}soils.umn.edu

Studies of solute transport through soil and attendant environmental impacts are hampered by the lack of methods for continuous monitoring of solute concentration. Measurement of bulk soil electrical conductivity (EC_b) using time domain reflectometry (TDR) is a promising technique, but it is indirect, and estimation of solute concentration from such measurements requires a model relating soil solution electrical conductivity (EC_w) to EC_b. Several models of varying complexity exist, but further testing is required to determine their relative merits and applicability. This study was conducted to determine the efficiency of various models that use different methods of estimating the tortuosity factor, F_g, in order to estimate EC_w from EC_b. All models assume that the ratio of EC_b/EC_w is proportional to soil water content, , with F_g as the coefficient of proportionality. In this study, two types of models were compared, those in which F_g is obtained from soil hydraulic properties and those in which F_g is estimated as it is in gas diffusion models, except with rather than porosity as the independent variable. Measurements were conducted in a sandy soil, across a range of EC_w from 0.10 to 0.56 S m^-1. The models in which F_g is obtained from soil hydraulic properties did not perform as expected. The results with the gas diffusion analog models were variable; the most successful of these was based on the 1959 model of Marshall, in which F_g is a power function of , ^b. Optimal results were obtained with , not far from Marshall's suggested value of 0.5 for gas diffusion. We conclude that there is no benefit to the use of soil hydraulic properties in estimating EC_w from EC_b measurements, at least for sandy soils, where simpler relationships appear to provide superior results.

Abbreviations: BVG, Burdine–van Genuchten model • EC_b, bulk soil electrical conductivity • EC_w, solution electrical conductivity • F_g, tortuosity factor • F_g(MF1), first F_g prediction method of the Mualem–Friedman model • F_g(MF2), second F_g prediction method of the Mualem–Friedman model • MVG, Mualem–van Genuchten model • PIM, Pulse Input Method • SIM, Step Input Method • TDR, time domain reflectometry • %Clay, percentage clay

This article has been cited by other articles:

				W. K. Jung, N. R. Kitchen, K. A. Sudduth, R. J. Kremer, and P. P. Motavalli Relationship of Apparent Soil Electrical Conductivity to Claypan Soil Properties Soil Sci. Soc. Am. J., May 6, 2005; 69(3): 883 - 892. [Abstract] [Full Text] [PDF]

				T. J. Kelleners, R. W. O. Soppe, J. E. Ayars, and T. H. Skaggs Calibration of Capacitance Probe Sensors in a Saline Silty Clay Soil Soil Sci. Soc. Am. J., May 1, 2004; 68(3): 770 - 778. [Abstract] [Full Text] [PDF]

				Y. Hamed, M. Persson, and R. Berndtsson Soil Solution Electrical Conductivity Measurements Using Different Dielectric Techniques Soil Sci. Soc. Am. J., July 1, 2003; 67(4): 1071 - 1078. [Abstract] [Full Text] [PDF]