ARS | Publication request: A REVIEW OF ADVANCES IN DIELECTRIC AND ELECTRICAL CONDUCTIVITY MEASUREMENT IN SOILS USING TIME DOMAIN REFLECTOMETRY

Submitted to: Vadose Zone Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 2, 2003
Publication Date: February 2, 2003
Citation: Robinson, D.A., Jones, S.B., Wraith, J.W., Or, D., Friedman, S.P. 2003. A review of advances in dielectric and electrical conductivity measurement in soils using time domain reflectometry. Vadose Zone Journal. v. 2. p. 444-475.

Interpretive Summary: Time domain reflectometry is widely used in the agricultural sciences to determine water content and bulk electrical conductivity of soils. This review examines work conducted over the last 30 years critically examining our understanding and presenting gaps in our knowledge.

Technical Abstract: Substantial advances in simultaneous measurement of water content and bulk soil electrical conductivity using time domain reflectometry (TDR) have been made over the last two decades. The key to success is its ability to accurately measure the permittivity of a material and the fact that there is a good relationship between the permittivity of a material and its water content. The aim of this review is to summarize and examine advances that have been made in terms of measuring permittivity and bulk electrical conductivity. Topics considered cover optimal probe design and construction, and the processing of waveforms to get the best permittivity and electrical conductivity determinations. Some of the different commercial TDR units are discussed in terms of their performance and their advantages and disadvantages. It is hoped to provide an informative guide to the more technical aspects of permittivity and electrical conductivity measurement using TDR for the novice and expert alike.