Key Points
- Seven trials over three years compared urea to DCn and SustaiN. SustaiN is urea which contains a urease inhibitor that is designed to reduce gaseous loss of N (volatilisation). DCn contains the active ingredient DCD which, as a nitrification inhibitor, slows the transformation of ammonium to nitrate.
- Soil mineral N was measured in trials to calculate N application rates. The fertilisers were broadcast during stemextension. Yield response was compared with a control.
- No advantage to SustaiN was found in five of the seven trials. At most of these sites, rain fell within a few days of treatments being applied, so there was no benefit to using SustaiN over urea or DCn to reduce volatilisation.
- Our results show that SustaiN may be a useful option where growers are broadcasting fertiliser in dry conditions (but not always, as shown in the Temuka 3 trial).
- No advantage to DCn was found in four of the seven trials.