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 An erratum has been published 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 (28) Citing Articles via Google Scholar Google Scholar Articles by Arya, L. M. Articles by van Genuchten, M. Th. Search for Related Content PubMed Articles by Arya, L. M. Articles by van Genuchten, M. Th. GeoRef GeoRef Citation Agricola Articles by Arya, L. M. Articles by van Genuchten, M. Th.

DIVISION S-1-SOIL PHYSICS

Relationship between the Hydraulic Conductivity Function and the Particle-Size Distribution

^a US Salinity Lab., USDA-ARS, 450 W. Big Springs Rd., Riverside, CA 92507 USA

larya{at}ussl.ars.usda.gov

We present a model to compute the hydraulic conductivity, K, as a function of water content, , directly from the particle-size distribution (PSD) of a soil. The model is based on the assumption that soil pores can be represented by equivalent capillary tubes and that the water flow rate is a function of pore size. The pore-size distribution is derived from the PSD using the Arya-Paris model. Particle-size distribution and K() data for 16 soils, representing several textural classes, were used to relate the pore flow rate and the pore radius according to , where q_i is the pore flow rate (cm³ s^-1) and r_i is the pore radius (cm). Log c varied from about -2.43 to about 2.78, and x varied from 2.66 to 4.71. However, these parameters did not exhibit a systematic trend with textural class. The model was used to independently compute the K() function, from the PSD data for 16 additional soils. The model predicted K() values from near saturation to very low water contents. The agreement between the predicted and experimental K() for individual samples ranged from excellent to poor, with the root mean square residuals (RMSR) of the log-transformed K() ranging from 0.616 to 1.603 for sand, from 0.592 to 1.719 for loam, and from 0.487 to 1.065 for clay. The average RMSR for all textures was 0.878.

Abbreviations: PSD, particle-size distribution • RMSR, root mean square residuals

This article has been cited by other articles:

				J. Simunek, M. Th. van Genuchten, and M. Sejna Development and Applications of the HYDRUS and STANMOD Software Packages and Related Codes Vadose Zone J., May 27, 2008; 7(2): 587 - 600. [Abstract] [Full Text] [PDF]

				C. J. Murray, A. L. Ward, and J. L. Wilson Influence of Clastic Dikes on Vertical Migration of Contaminants at the Hanford Site Vadose Zone J., November 20, 2007; 6(4): 959 - 970. [Abstract] [Full Text] [PDF]

				J. M. Keller and G. W. Gee Comparison of American Society of Testing Materials and Soil Science Society of America Hydrometer Methods for Particle-Size Analysis Soil Sci. Soc. Am. J., May 23, 2006; 70(4): 1094 - 1100. [Abstract] [Full Text] [PDF]

				P. Lehmann, P. Wyss, A. Flisch, E. Lehmann, P. Vontobel, M. Krafczyk, A. Kaestner, F. Beckmann, A. Gygi, and H. Fluhler Tomographical Imaging and Mathematical Description of Porous Media Used for the Prediction of Fluid Distribution Vadose Zone J., January 26, 2006; 5(1): 80 - 97. [Abstract] [Full Text] [PDF]

				S. I. Hwang and S. E. Powers Using Particle-Size Distribution Models to Estimate Soil Hydraulic Properties Soil Sci. Soc. Am. J., July 1, 2003; 67(4): 1103 - 1112. [Abstract] [Full Text] [PDF]

				Q. Wang, R. Horton, and M. Shao Horizontal Infiltration Method for Determining Brooks-Corey Model Parameters Soil Sci. Soc. Am. J., November 1, 2002; 66(6): 1733 - 1739. [Abstract] [Full Text] [PDF]