Soils containing enough soluble salts to interfere with the ability of plants to take up water. The conventional measurement that determines the salinity of soil is a deciSiemens meter; soils are considered saline if the conductivity of their saturation extract solution exceeds 4 deciSiemens meter-1. This unit of measure closely approximates the ionic salt concentration, and it is relatively easy to evaluate. The most common salts are composed of mixtures of sodium, calcium, and magnesium with chlorides, sulfates, and bicarbonates. Other less soluble salts of calcium sulfate and calcium and magnesium carbonate may be present as well. The pH is commonly less than 8.5.

In saline soils, there is often what is known as a perched water table—water close to the surface of the land. This phenomenon can be caused by restricting layers of fine clay within the soil, or by the application of waters at a...