The invention relates to a homogeneous, solid, particulate, urea ammonium sulphate-based composition comprising urea ammonium sulphate and a urease inhibitor of the type phosphoric triamide, in particular N-(n-butyl) thiophosphoric triamide (nBTPT), wherein the urea ammonium sulphate-based composition is characterized in that it comprises a magnesium sulphate. The composition according to the invention has improved properties for reducing ammonia loss by urease activity in the soil and is in particular suitable as a fertilizer. The invention further relates to a method for the manufacture of a homogeneous, solid, particulate urea ammonium sulphate-based composition comprising urea, ammonium sulphate and a urease inhibitor of the type phosphoric triamide, in particular N-(n-butyl) thiophosphoric triamide (nBTPT), as well as to a composition of kit of parts comprising an amount of a) magnesium sulphate； b) a urease inhibitor of the type phosphoric triamide, preferably N-(n-butyl) thiophosphoric triamide (nBTPT)； c) optionally, an alkaline or alkaline-forming compound, selected from the group of calcium oxide, zinc oxide, magnesium oxide, calcium carbonate, and mixtures thereof, and d) optionally, one or more anti-caking and/or moisture-repellent and/or anti-dust compounds.
