ARS | Publication request: Column displacement experiments to evaluate electrical conductivity effects on electromagnetic soil water sensing

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 31, 2010
Publication Date: October 31, 2010
Citation: Schwartz, R.C., Evett, S.R., Pelletier, M.G. 2010. Column displacement experiments to evaluate electrical conductivity effects on electromagnetic soil water sensing [abstract]. In: ASA-CSSA-SSSA Annual Meeting Abstracts, October 31-November 4, 2010, Long Beach, California. Paper No. 301-7. 2010 CDROM.

Technical Abstract: Bulk electrical conductivity (EC) in superactive soils has been shown to strongly influence electromagnetic sensing of permittivity. However, these effects are dependent on soil water content and temperature as well as the pore water conductivity. We carried out isothermal column displacement experiments at saturation to evaluate the influence of changes in bulk EC on soil permittivity measurements with time domain reflectometry (TDR) and a capacitance sensor (TE-5). Changes in permittivity inferred by TDR measurements could be properly described using the phase velocity equation for transversal electromagnetic waves. In contrast, permitivities measured using capacitance sensors exhibited a negative response to bulk EC in a fine sand and a positive response in a clay loam.