AS is better than urea on S-deficient soils, because it has

AS is better than urea on S-deficient soils, because it has Sulphuric acid.
Ammonium sulphate is an inorganic sulphate salt obtained by the reaction of sulfuric acid with two equivalents of ammonia.
It is an important source of nitrogen (N) and sulphur (S) for crop nutrition. It can be used as a directly applied fertilizer as well as a component of NPK blends and compound fertilizers.