Electromagnetic Induction (EMI)


EMI is a non invasive, non contact technique for the measurement of apparent soil electrical conductivity (ECa). EMI uses a transmitter coil to induce an electromagnetic field into the soil and one or more receiver coils to detect the secondary fields generated by the resulting eddy currents. The non contact capabilities make this a very adaptable technique particularly suited to mapping soil variability.


Mapping saline soils [1].

Mapping soil variability in Precision Agriculture [2].


It is a correlative technique with ECa a function of a number of soil properties.

Development Status



Description of the principle of operation [3]


1. Rhoades JD. 1993. Electrical conductivity methods for measuring and mapping soil salinity. In: D. Sparks (ed.), Advances in Agronomy 49: 201–251.

2. Corwin DL, Lesch SM. 2003. Application of soil electrical conductivity to precision agriculture: theory, principle and guidelines. Agronomy Journal 95: 455–471.

3. McNeill (1980).