An update on the performance of protected urea
An ongoing study in three Teagasc research centres has shown that protected urea (46% Urea NBPT-NPPT) remained an effective nitrogen fertiliser product in 2025.
The plot trial study, hosted in Moorepark, Clonakilty and Athenry, was established to demonstrate the effectiveness of protected urea as a nitrogen fertiliser product for grassland systems.
Commencing this spring and being led by Dr. Áine Murray, this study is comparing the effect of different chemical N fertiliser types at four fertiliser application rates on grass growth in plots under simulated grazing conditions.
Two fertiliser products, Calcium Ammonium Nitrate (CAN) and urea protected with NBPT-NPPT protection, are being compared against each other and also against a zero-nitrogen control. The fertilisers are being compared at 4 different rates – 75kg N/ha, 150kg N/ha, 300kg N/ha and 450kg N/ha, with applications taking place between February and August.
Providing an update on the study, Dr. Áine Murray explained: “Herbage production and performance across the three sites have recently been collated and, akin to the results released earlier this year, no major differences have been witnessed in the plots receiving either protected urea (46% Urea NBPT-NPPT) or CAN across each of the four rate treatments at any of the individual sites.”
Figure 1: Average of three sites – total herbage production
Dr. Murray added: “At the application rate of 150kg N/ha, paddocks receiving protected urea yielded 10,926kg DM/ha on average across the three sites, whereas the CAN paddocks yielded 10,650kg DM/ha, indicated the protected urea did deliver for grass growth in 2025.”
Table 1: Average grass yield from three Teagasc sites based on fertiliser treatment
| Treatment | Yield (kg DM/ha) |
| 0 (control) | 7,842 |
| 75 CAN | 9,399 |
| 75 Protected Urea | 9,489 |
| 150 CAN | 10,650 |
| 150 Protected Urea | 10,926 |
| 300 CAN | 12,174 |
| 300 Protected Urea | 12,238 |
| 450 CAN | 12,980 |
| 450 Protected Urea | 13,689 |