Electrical conductivity (EC) is the ability or inability of a substance to allow better flow of electricity. Pure water strongly resists the passage of an electric current. However, when salts are dissolved in water they improve its conductivity, so the greater the quantity of dissolved salts water contains the higher will be its conductivity reading. A measure of electrical conductivity is therefore commonly used as a fairly reliableindicator of the degree of salinity of a water sample. It does not identify the specific dissolved salts, or the affects on crops or soils.