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12.3 Water Classification Types
Class 1: 0 to 175 ppM
Low Salinity Water - can be used for most crops and soils, with all methods of
water application, with little likelihood that a salinity problem will develop.
Some leaching may be required, but this should occur under normal irrigation
practices, except in soils with extremely low permeability.
Class 2: 175 to 500 ppM
Medium Salinity Water - can be used if a moderate amount of leaching occurs.
Plants with medium salt tolerance can be grown, usually without special practices
for salinity control. Sprinkler irrigation with the more saline waters in this group
may cause leaf scorch on salt sensitive crops, especially at high temperatures in
the daytime, and with low water application rates.
Class 3: 500 to 1500 ppM
High Salinity Water - cannot be used on soils with restricted drainage.
Even with adequate drainage, special management techniques for salinity
control may be required, and the salt tolerance of the crops to be
irrigated must be considered.
Class 4: 1500 to 3500 ppM
Very High Salinity Water - not suitable for irrigation under ordinary conditions.
For use, soils must be permeable, drainage adequate, water must be applied in
excess to provide considerable leaching, and salt tolerant crops must be selected.
Class 5: Above 3500 ppM
Extremely High Salinity Water - may be used only on permeable well- drained
soils under good management, especially in relation to leaching. Also can be
used for salt-tolerant crops, or for occasional emergency use.