Reaction products and methods for making and using such reaction products are provided. For example, a reaction product comprising an adduct formed from urea, formaldehyde, and a urease inhibitor is described, which can be provided in various forms. For example, such a reaction product can be in the form of a solid or solution. Such a reaction product can also be combined with one or more additional components, including but not limited to, additional urease inhibitor and/or a nitrogen-based fertilizer composition.

An inhibitor composition contains alkyl thiophosphoric triamide (or a mixture of alkyl thiophosphoric triamide and dicyandiamide), dissolved in a liquid medium comprising at least one organic solvent and at least one amine stabilizer, is useful in making fertilizer compositions and in a method of fertilizing target plants.

This invention relates to an improved urea-nitrogen stabilizer composition and methods, systems and apparatti for making thereof. The nitrogen stabilizer composition is incorporated into molten urea to result in a composition that contains less biuret, NMP, nitrogen stabilizer and/or impurities and provides an effective solid fertilizer. These compositions are useful in in odor control.