There are 3 types of salt affected soil
1. Saline soils
2. Sodic Soils
3. Saline sodic soils
Soils having soluble salts more than 4 dS/m in soil solution called saline soil
Soils having pH more than 8.5 or ESP more than 13 or ESR more than 15 called soidic soils
And soils having pH more than 8.5 also having ECe more than 4 called saline sodic soils
Most dangourous soils among these are sodic soils watter logged soils having soil water table very close to soil surface . I forgot the exact figure that how much is it ..