The Use of Electromagnetic Induction to Monitor Changes in Soil Moisture Profiles beneath Different Wheat Genotypes

There has been recent interest in the use of surface deployed geophysical methods to estimate soil moisture profiles. In this study we applied multi-coil, frequency domain, electromagnetic induction (EMI) geophysical surveys to determine electrical conductivity (σ) profiles of the root zone of four winter wheat (Triticum aestivum) genotypes, grown in randomized block experiment with four replicates. Field measurements of apparent electrical conductivity (σa) 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 ERT data. Changes in electrical conductivity of field soil, with depth computed from inversion of EMI data, over 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 water content by up to 30 percent. Comparing changes in electrical conductivity between reference profiles determined shortly after crop emergence, with 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 over time.

[1]  L. J. Clark,et al.  The effect of soil strength on the yield of wheat , 2008, Plant and Soil.

[2]  W. R. Whalley,et al.  The velocity of shear waves in unsaturated soil , 2012 .

[3]  H. Vereecken,et al.  Geophysical Methods for Field‐Scale Imaging of Root Zone Properties and Processes , 2015 .

[4]  A C Fowler,et al.  A model for water uptake by plant roots. , 2004, Journal of theoretical biology.

[5]  Johan Alexander Huisman,et al.  Three‐dimensional imaging of subsurface structural patterns using quantitative large‐scale multiconfiguration electromagnetic induction data , 2014 .

[6]  Andrew Binley,et al.  A Bayesian trans-dimensional approach for the fusion of multiple geophysical datasets , 2013 .

[7]  D. Corwin,et al.  Apparent soil electrical conductivity measurements in agriculture , 2005 .

[8]  L. A. Richards,et al.  Change of Electrical Conductivity With Temperature and the Relation of Osmotic Pressure to Electrical Conductivity and Ion Concentration for Soil Extracts , 1949 .

[9]  Harry Vereecken,et al.  Quantitative Two‐Layer Conductivity Inversion of Multi‐Configuration Electromagnetic Induction Measurements , 2011 .

[10]  Ian C Dodd,et al.  Genetic and management approaches to boost UK wheat yields by ameliorating water deficits. , 2011, Journal of experimental botany.

[11]  J. D. Mcneill.  Electromagnetic Terrain Conduc-tivity Measurement at Low Induction Numbers , 1980 .

[12]  C. Doussan,et al.  Estimation of the spatial variability of root water uptake of maize and sorghum at the field scale by electrical resistivity tomography , 2009, Plant and Soil.

[13]  Shmuel Assouline,et al.  Electrical Resistivity Tomography of the Root Zone , 2015 .

[14]  J. Araus,et al.  Field high-throughput phenotyping: the new crop breeding frontier. , 2014, Trends in plant science.

[15]  A. Binley,et al.  DC Resistivity and Induced Polarization Methods , 2005 .

[16]  Jan Vanderborght,et al.  Electromagnetic induction calibration using apparent electrical conductivity modelling based on electrical resistivity tomography , 2010 .

[17]  M. Everett,et al.  The Role of Water Content in Electrical Resistivity Tomography of a Vertisol , 2014 .

[18]  G. E. Archie.  The electrical resistivity log as an aid in determining some reservoir characteristics , 1942 .

[19]  P. Dietrich,et al.  Noninvasive Monitoring of Soil Static Characteristics and Dynamic States: A Case Study Highlighting Vegetation Effects on Agricultural Land , 2012 .

[20]  D. Parasnis,et al.  Reciprocity theorems in geoelectric and geoelectromagnetic work , 1988 .

[21]  M. A. Hilhorst.  A Pore Water Conductivity Sensor , 2000 .

[22]  R. W. Groom,et al.  Vertical Spatial Sensitivity and Exploration Depth of Low‐Induction‐Number Electromagnetic‐Induction Instruments , 2007 .

[23]  Jan Vanderborght,et al.  On the spatio-temporal dynamics of soil moisture at the field scale , 2014 .

[24]  P. Hallett,et al.  Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits. , 2011, Journal of experimental botany.

[25]  Andreas G. Lazari,et al.  Soil electrical conductivity as a function of soil water content and implications for soil mapping , 2006, Precision Agriculture.

[26]  Peter J. Gregory,et al.  Contributions of roots and rootstocks to sustainable, intensified crop production. , 2013, Journal of experimental botany.