Leaching of Saline Soil

the removal of excess salts from the plowing and subplowing horizons of the soil by flushing with water; the principal means of controlling salinization of irrigated land. Before leaching the surface of the field is graded, tilled deeply, and divided into small plots of 0.2–0.3 hectares (ha) or greater by ridges. The plots are then flooded with water. Leaching norms, that is, the amount of water per ha needed to dissolve and supplant salts from saline soil, are established, based on the degree of salinization, the composition of the salts (sulfates, chlorides, carbonates), the water permeability, and the water table level. To desalinize the 1-meter soil layer, 4,000–10,000 cu m/ha of water are needed, whereas as much as 50,000 cu m/ha may be required for the 3-meter layer. Saline soils are usually leached in the late autumn when evaporation is least and the water table is low. The percolating water is removed through desalinization drainage structures.