Measurement of low matric potentials with porous matrix sensors and water-filled tensiometers

A - Papers appearing in refereed journals

Whalley, W. R., Lock, G., Jenkins, M., Peloe, T., Burek, K., Balendonck, J., Take, W. A., Tuzel, I. H. and Tuzel, Y. 2009. Measurement of low matric potentials with porous matrix sensors and water-filled tensiometers. Soil Science Society of America Journal. 73 (6), pp. 1796-1803.

AuthorsWhalley, W. R., Lock, G., Jenkins, M., Peloe, T., Burek, K., Balendonck, J., Take, W. A., Tuzel, I. H. and Tuzel, Y.
Abstract

Water-filled tensiometers are widely used to measure the matric potential of soil water. It is often assumed that, because these give a direct reading, they are accurate. With a series of laboratory tests with model laboratory systems of increasing complexity we show that the output of water-filled tensiometers can, particularly in drying soils, be in serious error. Specifically, we demonstrated that water-filled tensiometers can indicate a steady matric potential, typically between −60 and −90 kPa, when the soil is much drier. We demonstrate the use of water-filled tensiometers that can measure matric potentials smaller than −100 kPa in the laboratory and in the field. The physics of the failure of water-filled tensiometers is discussed. When the matric potential was greater than −60 kPa, in laboratory and field tests water-filled and porous matrix sensors were in good agreement. In the field environment the porous matrix sensor was useful because it allowed early detection of the failure of water-filled tensiometers. In dry soils (matric potential < −60 kPa) the porous matrix sensor was more reliable and accurate than the water-filled tensiometer.

Year of Publication2009
JournalSoil Science Society of America Journal
Journal citation73 (6), pp. 1796-1803
Digital Object Identifier (DOI)doi:10.2136/sssaj2008.0400
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeSEF
Farm Level Optimal Water Management: Assistant for Irrigation under Deficit - FLOWAID
Bio-physics of the soil-root interface
Output statusPublished
Publication dates
Online30 Nov 2009
Copyright licensePublisher copyright
ISSN0361-5995
PublisherSOIL SCI SOC AMER

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