Description
Salts in the soil come from naturally occurring minerals in the soil or in the irrigation water; from improperly applied manure, lime, or fertilizer; or from de-icing salts. If the concentration of salts dissolved in the soil water is too high, plants can't get enough water for healthy growth. As a result, growth slows and the leaves turn yellow. Salt also enters the plant, where it is deposited in the tips or edges of leaves, as the water in which the salt was dissolved evaporates. When enough salt accumulates, the tissue at the edge of the leaves turns yellow, then dies. As water evaporates from the soil, the salts become more concentrated and more damaging. Salt damage and drought damage often occur together, compounding the problem. Salt accumulation in the soil is often caused by poor drainage, which keeps the salts from being leached through the soil. (For information on inexpensive laboratory tests for salts, see Soil Testing.)
Control
Leach salts from the soil with periodic heavy irrigation. Enough water should be applied to wash the salts below the plant roots. If the soil does not drain well, improve drainage according to the instructions in Soil Types, Soil Structure, Groundwater. Keep the soil moist enough so that the plants are never under stress. Follow label instructions when using fertilizer. Apply the fertilizer to moist soil, and water it in thoroughly. If you are applying lime to soil already high in salts, use ground limestone rather than agricultural lime or quicklime; it is less soluble, and less likely to cause problems. If you have a salt problem, do not use bagged steer or poultry manure (feedlot manure), both of which contain high levels of salts.
