13.4 Salinity
Sodium and chloride occur naturally in
soils and waters, and are added by
residential, commercial and industrial
activity. Aquatic organisms and vegetation,
including crops and roadside grasses,
shrubs and trees, tolerate various
concentrations of sodium and chloride.
The following classification is used by the
U.S. Department of Agriculture to indicate
the degree of hazard of saline soils to food
crops. It is based on conductivity and
salinity hazard. (Conductivity can be
converted to approximate mg/L dissolved
solids).