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The Use of Electromagnetic Induction to Monitor Changes in Soil Moisture Profiles beneath Different Wheat Genotypes
Author(s) -
Shanahan Peter W.,
Binley Andrew,
Whalley W. Richard,
Watts Christopher W.
Publication year - 2015
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2014.09.0360
Subject(s) - water content , electrical resistivity and conductivity , soil science , environmental science , emi , soil water , conductivity , electromagnetic induction , moisture , electrical resistivity tomography , materials science , geology , composite material , electromagnetic interference , chemistry , geotechnical engineering , electronic engineering , electrical engineering , engineering , electromagnetic coil
There has been recent interest in the use of surface‐deployed geophysical methods to estimate soil moisture profiles. In this study, we applied multicoil, frequency domain, electromagnetic induction (EMI) geophysical surveys to determine electrical conductivity (σ) profiles of the root zone of four winter wheat ( Triticum aestivum L.) genotypes grown in a randomized block experiment with four replicates. Field measurements of apparent electrical conductivity (σ a ) were obtained at sites with two different soil textures. We used the cumulative sensitivity model to predict EMI conductivity data from the conductivity profile measured with electrical resistivity tomography (ERT) on a subset of the plots we investigated. During the inversion of the EMI data, conductivities were adjusted on all plots so that they were consistent with the ERT data. Changes in electrical conductivity of field soil, with depth computed from inversion of the EMI data, during the growth period were compared with measured changes in soil water content. Laboratory measurements confirmed a positive correlation between electrical conductivity and soil water content. Between crop emergence and maturity, water extraction by the different wheat genotypes reduced the water content by up to 30% Comparing changes in electrical conductivity between reference profiles determined shortly after crop emergence and electrical conductivity profiles at later dates as the crop matured, we were able to use EMI to remotely monitor moisture extraction by the roots of different wheat genotypes with depth and time.