The Effect of Soluble Salts on Soil Water Availability

Water held in the soil between the field capacity and permanent wilting point is referred to as available soil water. The concept is based on the premise that the only factor affecting availability is the attraction of water for soil solid surfaces and the attraction of water molecules for each other. However, when excess amounts of soluble salts are present in the soil solution, these, too, impose a restraint on availability of water to the plant through the phenomenon referred to as osmotic potential. The effect of excess soluble salts on water availability can var with the amount and kind of soluble salt, the kind of crop, and the atmospheric conditions as they affect rate of evaporation of water from plants and the soil