Compositions and methods for coating of nitrification inhibitors with a solution containing a high concentration of urease inhibitors

A dry, flowable additive composition adapted for combination with a fertilizer to increase longevity of plant available nitrogen in the soil from the fertilizer, the dry, flowable additive composition comprising:

• a) a powder or granular dicyandiamide (DCD) comprising 80-99% of the dry flowable additive composition, the powder or granular DCD is a core of the dry, flowable additive composition that is evenly coated with
• b) a coating formulation comprising N-(n-butyl)thiophosphoric triamide (NBPT) as a urease inhibitor solubilized within dimethyl sulfoxide (DMSO), the NBPT comprises 80-90 wt % of the coating formulation.