Soil salinity that occurs across large areas can be assessed with reduced amounts of soil sampling through the use of portable
instruments that measure soil electrical conductivity. This allows the extent and severity of areas of different conductivity to be quickly and
reliably delineated. The conductivity of the soil is measured through its electromagnetic induction, and so the instruments used are
commonly known as EM meters or EMI meters. EM meters measure the apparent soil electrical conductivity (ECa). If a significant
correlation is found between soil salinity and ECa, the measurements can be converted to other results (such as ECe, the electrical
conductivity of a soil saturation extract) by calibration for soil type.