has role nitrogen fertilizer inorganic sulfate salt fertilizer ammonium salt ammonium sulfate (NH4)2SO4 An inorganic sulfate salt obtained by reaction of sulfuric acid with two equivalents of ammonia. A high-melting (decomposes above 280degreeC) white solid which is very soluble in water (70.6 g/100 g water at 0degreeC; 103.8 g/100 g water at 100degreeC), it is widely used as a fertilizer for alkaline soils. ammonium sulfate (2:1) ammonium sulphate diammonium sulfate diazanium sulfate mascagnite sulfuric acid ammonium salt (1:2) sulfuric acid, diammonium salt sulphate of ammonia