The invention relates to a solid, particulate, urea-based blend composition comprising a urea-based compound in particulate form, a component comprising an ammonium source in particulate form, a urease inhibitor of the type phosphoric triamide, an alkaline or alkaline-forming inorganic or organic compound that is able to interact with the component comprising an ammonium source in particulate form, selected from the group consisting of metal oxides, metal carbamates, metal hydroxides, metal acetates and any mixtures thereof, or from the group of organic bases consisting of ammonia, amines, amides, adenines, amidines, guanidines, anilines, carbamates, thiazoles, triazoles, pyridines; imidazoles, benzimidazoles, histidines, phosphazenes, and any mixture thereof, wherein the urea-based blend composition further comprises a cation source, different from the alkaline or alkaline-forming inorganic or organic compound, comprising a cation selected from the group consisting of Fe2+, Fe3+, Mn2+, Zn2+, Cu+, Cu2+, Ni2+, Ag+, Pt2+, Ru2+, Co3+ and Cr3+.