Precision Agriculture

, Volume 7, Issue 6, pp 393–404 | Cite as

Soil electrical conductivity as a function of soil water content and implications for soil mapping

  • Eric C. Brevik
  • Thomas E. Fenton
  • Andreas Lazari


Apparent soil electrical conductivity (ECa) has shown promise as a soil survey tool in the Midwestern United States, with a share of this interest coming from the precision agriculture community. To fully utilize the potential of ECa to map soils, a better understanding of temporal changes in ECa is needed. Therefore, this study was undertaken to compare temporal changes in soil ECa between different soils, to investigate the influence of changes in soil water content on soil ECa, and to explore the impacts these ECa changes might have on soil mapping applications. To this end, a 90 m long transect was established. Soil ECa readings were taken in the vertical and horizontal dipoles at five points once every one to two weeks from June until October in 1999 and 2000. At the same time, soil samples were collected to a depth of 0.9 m for volumetric soil water content analysis. Soil ECa readings were compared to soil water content. At four of the five sites linear regression analysis yielded r 2 values of 0.70 or higher. Regression line slopes tended to be greater in lower landscape positions indicating greater ECa changes with a given change in soil water content. Two of the soils had an ECa relationship that changed as the soils became dry. This is an item of concern if ECa is to be used in soil mapping. Results indicated that soil water content has a strong influence on the ECa of these soils, and that ECa has its greatest potential to differentiate between soils when the soils are moist. Soil water content is an important variable to know when conducting ECa surveys and should be recorded as a part of any report on ECa studies.


EM-38 Electromagnetic induction Electrical conductivity Soil mapping 


Acknowledgments and Disclaimer

The research reported in this paper was done when the first author was a graduate student in the Agronomy Department at Iowa State University. Trade names or commercial products are given solely for the purpose of providing information on the exact equipment used in this study, and do not imply recommendation or endorsement by Iowa State University or Valdosta State University. Journal Paper No. J-19326 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA, Project No. 3934, and supported by Hatch Act and State of Iowa.


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Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Eric C. Brevik
    • 1
  • Thomas E. Fenton
    • 2
  • Andreas Lazari
    • 3
  1. 1.Department of Physics, Astronomy, and GeosciencesValdosta State UniversityValdostaUSA
  2. 2.Soil Survey ProgramIowa State UniversityAmesUSA
  3. 3.Department of Mathematics and Computer ScienceValdosta State UniversityValdostaUSA

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