An electromagnetic induction technique for reconnaissance surveys of soil salinity hazards

Abstract

An assessment has been made of an electromagnetic induction (EM) technique for reconnaissance surveys of soil salinity. The instrument used provides values of apparent electrical conductivity to depths ranging from 7.5 to 60 m. A comparison of EM values with actual profile salinities at 19 sites of widely differing geological and geomorphic origin showed that approximately 65% of the variance of EM values is explained in terms of salinity alone. An area of 10000 km2 in the mid-Lachlan River Valley of New South Wales was surveyed with a grid spacing of approximately 5 km at a rate of 30-40 sites per day. This permitted the definition of areas of high subsoil apparent conductivity and hence, by inference, of high soil salinity. The EM technique was demonstrated to have a potential for providing a significant contribution to land use planning at both a regional and local scale, by defining areas of possible salinity hazard.

Mapping clay content variation using electromagnetic induction techniques

“…This is best illustrated in the work by Williams and Baker (1982) who found soils of different mineralogy produced different regression relationships between EM34 and soil salinity (as measured in laboratory analysis). What would seem appropriate is the division of the landscape into similar mineralogical or physiographical units prior to site selection, thereby ensuring various parts of the landscape are equally represented in a final calibration model.…”

Apparent soil electrical conductivity mapping as an agricultural management tool in arid zone soils

“…Apparent soil electrical conductivity (EC a ) survey information has been widely used in agriculture to measure various soil physico-chemical properties. Techniques for predicting soil salinity from EC a survey data have been discussed by numerous authors, including Williams and Baker (1982), Rhoades et al (1989Rhoades et al ( , 1999, Hendrickx et al (1992), Rhoades (1992Rhoades ( , 1996, and Lesch et al (1995a). Other soil properties that have also been successfully mapped using EC a data include clay content (Williams and Hoey, 1987), depth to clay layers (Doolittle et al, 1994), and moisture content (Sheets and Hendrickx, 1995;Kachanoski et al, 1988).…”

Soil Conductivity as a Measure of Soil and Crop Status—A Four‐Year Summary

“…Sudduth and Kitchen (1993) used EMI methods to estimate clay pan depth in soil. Electromagnetic methods have been used to map soil salinity hazards (Williams and Baker, 1982;Corwin and Rhoades, 1982). Electrical conductivity methods have been shown to be sensitive to high nutrient levels (Eigenberg et al, , 2000 and have been used to detect ionic concentrations on or near the soil surface resulting from field application of cattle feedlot manure.…”