Estimation of Soil-Profile Properties From Electromagnetic Induction.

Electromagnetic induction (EMI) has become widely used for measuring the apparent electrical conductivity of soils.  Where apparent conductivity is measured to several depths of investigation, estimates can be made of the electrical properties of the soil profile.  For example, where (i) there is significant contrast in conductivity between a surficial layer and underlying material, and (ii) the thickness of the surficial layer lies within the general depth of investigation, estimates of the conductivity of the surficial layer, the thickness of the layer, and the conductivity of the underlying material can show reasonable agreement with the results of invasive sampling.  Situations where there is low-to-modest contrast and problematic thickness demonstrate the limitations of the technique.