Urease & Nitrification Inhibitors

Nitrogen is the element that is needed in the most abundance in soils, however around 70% of nitrogen fertiliser is lost due to nitrification and subsequent denitrification. Nitrification is performed by bacteria and converts the unusable forms of nitrogen: ammonia, ammonium-containing or urea-containing which are found in fertiliser, to the usable forms of ammonium and nitrates. Nitrification inhibitors slow down this process, enabling less nitrogen to be lost to the soil and meaning more nitrogen makes its way to the plant roots. When nitrates leach into the groundwater they can cause acute toxicity and can also produce methane- a greenhouse gas and inhibitors reduce this process. 

There are three different types of inhibitors: those that physically block the enzyme binding site, those that interrupt the reaction catalysis and a third class of chemical inhibitors- N-heterocyclic compounds which are not as well understood. Bisley sells mechanistic inhibitors (those that interrupt the reaction catalysis), most notably ammonium thiosulfate which produces volatile compounds (carbon disulfide and thiourea) that possess strong inhibitory impacts.