Urease inhibitor

A urease inhibitor is a substance that slows the hydrolytic action of the urease enzyme on urea, so as to reduce ammonia volatilisation.^[1] Once spread, urea normally undergoes rapid hydrolysis into ammonia that escapes into the atmosphere; the inhibitor delays this conversion.^[2] The European regulation on fertiliser products requires at least a 20 % reduction in the urea hydrolysis rate, measured in vitro fourteen days after application at a 95 % confidence threshold^[1].^[1] Inhibitors cannot be placed on the market under internal production control module A; module B followed by module C offers a viable route.^[3] In Yara's data, the "urea + urease inhibitor" scenario assumes a 70 % drop in ammonia emissions^[2].^[2]