What are soluble salts and how are they measured?
The term soluble salts refers to the inorganic soil constituents (ions) that are dissolved in the soil water. Pure water is a very poor conductor of electric current, whereas water containing dissolved salts conducts current approximately in proportion to the amount of salt present. Thus, measurement of the electrical conductivity of a soil extract gives an indication of the total concentration of soluble salts in the soil. The electrical conductivity measurement is usually reported in units of millimhos per centimeter (mmhos/cm), although some labs report decisemens per meter (dS/m). One decisemen per meter is equal to one mmhos/cm. Why are they important? Soluble salt levels in the soil are important, because high soluble salts can reduce water uptake by plants, restrict root growth, cause burning of the foliage, inhibit flowering, and limit fruit and vegetable yields. Sensitivity to soluble salts differs among plant species/cultivars and their stage of growth. Seed germination and s
