Electrical conductivity (EC) is a measurement of water’s ability to conduct electricity. EC is related to water temperature and the total concentration, mobility, valence and relative concentration of ions. Generally speaking, higher EC means more electrolytes in the water. Since most salts can be ionized, EC can also represent the amount of total dissolved solids. Water with high EC is unsuitable for irrigation. Thus EC is an important criterion for irrigation water quality. EC is the reciprocal of electrical resistivity which is measured as the electric current that passes through a 1-centimeter long liquid column with a cross-sectional area of one square cm. Its unit is mho/cm. If the EC value is very low, it can also be expressed in the unit of mmho/cm or μmho/cm.