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A profiling TDR probe for water content and electrical conductivity measurements of soils
Author(s) -
Persson M.,
Dahlin T.
Publication year - 2010
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2010.01306.x
Subject(s) - reflectometry , soil water , water content , infiltration (hvac) , soil science , conductivity , electrical resistivity and conductivity , dielectric , environmental science , materials science , analytical chemistry (journal) , mineralogy , chemistry , time domain , geology , environmental chemistry , geotechnical engineering , composite material , optoelectronics , computer science , computer vision , engineering , electrical engineering
Measurements of water content profiles are of great interest in hydrology and soil science. Time domain reflectometry (TDR) is a well‐established method for water content measurements; however, most TDR probe designs are suitable for measurements in only a small soil volume. In this article, a 1‐m long TDR profiling probe with five measurement sections is described. Unlike most other previous profiling probes, our probe allows for both dielectric permittivity ( ε ) and electrical conductivity ( σ a ) measurements. The accuracy of the ε and σ a measurements was excellent; the precision of the measurements was, however, significantly poorer than with a 0.20‐m long standard three rod TDR probe. The new probe was installed in a field and successfully measured water content profiles during the growing season of 2009. During an infiltration experiment it was shown that because of its geometry, the profiling probe over‐estimated the wetting‐front velocity. At a 0.10‐m depth, the over‐estimation was almost 30%. The over‐estimate will be less significant at greater depths.