Salinity and Sodium Hazard of Irrigation Water

 

Salinity and Sodium Hazard of Irrigation Water
Electrical Conductivity (ECW), mmhos/cm	Salinity Hazard	SAR or SARadj	Sodium Hazard
0.00 – 0.75	Low	0 – 6 6 – 9 9 – 12 12+	Low Medium High Very High
0.75 – 1.50	Medium	0 – 6 6 – 8 8 – 10 10+	Low Medium High Very High
1.50 – 3.00	High	0 – 4 4 – 6 6 – 8 8+	Low Medium High Very High
3.00+	Very High	0 – 2 2 – 4 4 – 6 6+	Low Medium High Very High

 

Salinity hazard categories of low, medium, high, and very high are general. Please refer to the adjacent table entitled Salinity Hazard of Irrigation Water for Various Crops to determine the salinity hazard of irrigation water for specific crops.

Sodium hazard categorized as low, medium, high, and very high is defined as follows:

1. Low – no permeability problems exist.
2. Medium – usually no permeability problems expected, except when soils are high in clay and the EC_W is high or very high.
3. High – possible permeability problems. Water can be used on sandy soils if the leaching requirement is met. Gypsum or elemental sulfur may be required if the soils are sandy or silt loam. Soil should be tested annually to monitor salinity and sodic conditions.
4. Very high – Serious permeability problems are expected. Soils will require application of gypsum or elemental sulfur and leached with good quality water to maintain productivity. Soils should be tested annually to monitor salinity and sodic conditions.