An EC meter is a probe type tool which is used to measure the electrical conductivity at various depths in the soil profile.
EC is most commonly measured in milliSiemens/meter (mS/m) and expresses the ability for a material to conduct an electrical current.
EC has been proven to be closely related to several soil properties such as salinity, porosity, cation exchange capacity, water holding capacity, and soil drainage capability. It's another inexpensive tool that provides immediate feedback for soil and its ability to sustain as a healthy plant environment.
"Electrical Conductivity, the Pulse of the Soil" See Research Article