Leaching for Salinity Management Soluble salts that accumulate in soils must be leached below the crop root zone to maintain productivity. Leaching is the basic management tool for controlling salinity.
Water is applied in excess of the total amount used by the crop and lost to evaporation.
The strategy is to keep the salts in solution and flush them below the root zone. The amount of water needed is referred to as the leaching requirement or the leaching fraction. Excess water may be applied with every irrigation to provide the water needed for leaching. However, the time interval between leachings does not appear to be critical provided that crop tolerances are not exceed. Hence, leaching can be accomplished with each irrigation, every few irrigations, once yearly, or even longer depending on the severity on the salinity problem and salt tolerance of the crop.