Calculation

The sulphate content expressed as SO₃ is calculate from the following expression:
SO₃= 1.6 Bv gram/litre
where  v= volume of Sodium Hydroxide Solutionin mL
          B =normality of Sodium Hydroxide solution in mol/L.

Note
If the soil contains chlorides, the above test will not work properly , and other methods should be used.