USDA Salinity hazard ratings:
Low: 70 - 175 mg/l
Medium: 176 - 525 mg/l
High: 526 - 1,575 mg/l
Very high: more than 1,575 mg/l
Factors that affect the degree of salinity hazard
are: soil texture, soil permeability, drainage,
quantity of water applied and the salt tolerance of
the vegetation.