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 Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Gee, G. W. Articles by Mathison, J. Search for Related Content PubMed Articles by Gee, G. W. Articles by Mathison, J. GeoRef GeoRef Citation Agricola Articles by Gee, G. W. Articles by Mathison, J. Related Collections Flow Soil Analysis Soil Physics

The Influence of Hydraulic Nonequilibrium on Pressure Plate Data

^a Hydrology Group, Environmental Technology Division, Pacific Northwest National Laboratory, Richland, WA 99353, USA
^b Decagon Devices, Pullman, WA
^c Washington State University, Pullman, WA
* Corresponding author (glendon.gee{at}pnl.gov)

Received 12 March 2002.

Pressure plates are used routinely to measure water-retention characteristics of soils. Plates of varying porosity are used, depending on the pressure range of interest. For applied pressures up to 1.5 MPa, 15-bar porous ceramic plates with fine porosity are used because of their high bubbling pressure (>1.5 MPa), which limits airflow through the plate. The typical saturated hydraulic conductivity of the 15-bar plate is <3 x 10^-11 m s^-1. Low plate conductance coupled with decreasing soil hydraulic conductivities at high pressures strongly influence equilibrium times, which theoretically may extend to months or years. We measured the soil water pressures (suctions) for three soils, a sand, a silt loam, and a clay, placed on 15-bar pressure plates for 10 d or longer, with and without static loads and with and without using a kaolinite slurry to improve plate contact. Total matric suctions, inferred from peltier psychrometry data, were always <1.0 MPa. When sample height was increased from 1.5 to 3 cm, the water contents increased and total suctions decreased to 0.15 MPa for sand, 0.3 MPa for silt loam, and 0.55 MPa for clay. These data suggest that alternative methods other than pressure plates may be required to measure equilibrium water suctions of soils in reasonable times in the 1.5-MPa (15-bar) pressure range and that loading of the samples and use of kaolinite slurry appear to be ineffective in speeding equilibrium.

This article has been cited by other articles:

				M. Bittelli and M. Flury Errors in Water Retention Curves Determined with Pressure Plates Soil Sci. Soc. Am. J., July 14, 2009; 73(5): 1453 - 1460. [Abstract] [Full Text] [PDF]

				M. J. Curtis and V. P. Claassen An Alternative Method for Measuring Plant Available Water in Inorganic Amendments Crop Sci., November 24, 2008; 48(6): 2447 - 2452. [Abstract] [Full Text] [PDF]

				H. P. Cresswell, T. W. Green, and N. J. McKenzie The Adequacy of Pressure Plate Apparatus for Determining Soil Water Retention Soil Sci. Soc. Am. J., January 11, 2008; 72(1): 41 - 49. [Abstract] [Full Text] [PDF]

				S. S. Agus and T. Schanz Comparison of Four Methods for Measuring Total Suction Vadose Zone J., November 11, 2005; 4(4): 1087 - 1095. [Abstract] [Full Text] [PDF]

				Y. Mori, Y. Mori, J. W. Hopmans, A. P. Mortensen, and G. J. Kluitenberg Multi-Functional Heat Pulse Probe for the Simultaneous Measurement of Soil Water Content, Solute Concentration, and Heat Transport Parameters Vadose Zone J., November 1, 2003; 2(4): 561 - 571. [Abstract] [Full Text] [PDF]

				H. Fujimaki, H. Fujimaki, and M. Inoue A Transient Evaporation Method for Determining Soil Hydraulic Properties at Low Pressure Vadose Zone J., August 1, 2003; 2(3): 400 - 408. [Abstract] [Full Text] [PDF]

				H. Fujimaki, H. Fujimaki, and M. Inoue Reevaluation of the Multistep Outflow Method for Determining Unsaturated Hydraulic Conductivity Vadose Zone J., August 1, 2003; 2(3): 409 - 415. [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]