Ammonium Sulphate (AS)

Ammonium Sulphate (21-0-0 + 24% S) is a dual-nutrient nitrogen and sulphur fertilizer with valuable soil-acidifying properties. In an era of increasing sulphur deficiency across European and global agriculture — driven by reduced atmospheric SO₂ deposition since clean air regulations — ammonium sulphate has become an essential component of modern crop nutrition. The acidifying effect (each tonne lowers pH by approximately 0.1 units per hectare) makes it invaluable for alkaline and calcareous soils where nutrient lockup limits crop productivity. Also widely used as a raw material in NPK compound fertilizer manufacturing and as an industrial processing agent.

Ammonium sulphate provides nitrogen as NH₄⁺ (ammonium) which is immediately adsorbed by soil colloids, providing resistance to leaching and sustained availability. During nitrification (NH₄⁺ → NO₃⁻), hydrogen ions are released, gradually acidifying the rhizosphere — beneficial for crops that prefer slightly acidic conditions (blueberry, tea, potato, azalea) and for unlocking micronutrients (Fe, Zn, Mn) in alkaline soils. The 24% sulphur (as SO₄²⁻) is immediately plant-available, supporting protein synthesis, chlorophyll formation, and the production of sulphur-containing amino acids (cysteine, methionine) and volatile flavour compounds.

Ideal For

Store in dry conditions. Less hygroscopic than urea — good storage stability. Shelf life: 24 months. Crystal grade: more prone to dust; granular grade preferred for mechanical application. Store away from alkaline materials (lime, calcium nitrate) to prevent ammonia release.