Urease and nitrification inhibitors: what the difference means in the field

Nitrogen loss from urea and ammonium-based fertilizers happens in two steps, and the two inhibitor types act on different steps.

Urease inhibitors

Urease is the enzyme that hydrolyses urea to ammonia and carbon dioxide. Slowing it keeps nitrogen in the urea form for longer, which reduces ammonia volatilisation from surface-applied urea and UAN.

Nitrification inhibitors

Nitrification converts ammonium to nitrite and then nitrate. Slowing it keeps nitrogen in the ammonium form, which is less mobile in soil and less exposed to denitrification and leaching.

When a combined grade makes sense

Where both volatilisation and leaching are risks — surface-applied urea on warm, moist soil, for example — a dual inhibitor covers both steps. Where only one loss pathway matters, the single-function grade is usually the simpler choice.

Our range includes a urease inhibitor, a nitrification inhibitor and a dual grade. Dosage and application guidance are taken from the technical data sheet for each product and are not repeated here.