12 June 2025
Protected urea continues to deliver performance across multiple sites
Extensively proven and widely promoted as a key technology to reduce greenhouse gas and ammonia emissions from Irish grass-based systems, promising early results from a major Teagasc study should serve to instil further confidence in protected urea.
As a climate mitigation technology, the uptake of protected urea on Irish farms has varied by enterprise. When reported as the percentage of total fertiliser nitrogen used, protected urea usage has increased from 11% to 27% on the average dairy farm over the period of 2021 to 2023, according to the Teagasc National Farm Survey (NFS).
In an effort to increase both farmer and industry confidence on the effectiveness of protected urea as a chemical nitrogen solution on farms, a major plot-based study is underway at three Teagasc locations – Moorepark, Athenry and Clonakilty.
At application rates of 150kg N/ha and 250kg N/ha, previous research from the Teagasc Grassland Department has verified the role of protected urea as an effective nitrogen source to not only grow grass but to also protect the environment.
The latest research, commencing this spring and being led by Dr. Áine Murray, is comparing the effect of different chemical N fertiliser types at four fertiliser application rates on grass growth in plots under simulated grazing conditions, comparing the performance of 27% Calcium Ammonium Nitrate (CAN) with that of urea protected with NBPT-NPPT protection and 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.
The following splits are being used for the 75kg N/ha treatment: February (11kg N/ha); March (11kg N/ha); April (11kg N/ha); May (7kg N/ha); June (7kg N/ha); July (11kg N/ha); and August (10kg N/ha). Plots under the 150kg N/ha treatment will receive applications of 22kg N/ha in the months of February, March and April; 14kg N/ha in the months of May, June and July, and an application of 21kg N/ha in the months of July and August. Similarly, the 300kg N/ha treatment receives double for that of 150kg N/ha treatment at each rotation and 450kg N /ha receives its N applications following the same pattern: February (66kg N/ha); March (66kg N/ha); April (66kg N/ha); May (42kg N/ha); June (42kg N/ha); July (63kg N/ha); and August (63kg N/ha).
Speaking on the study, Dr. Áine Murray explained: “We’ve collated data from the first three simulated grazing rotations from across the three Teagasc research centres and, although full replication and verification of the results are required, the yield differences witnessed between the plots receiving NBPT-NPPT urea and CAN so far this year show no difference between the two fertilisers in terms of herbage production.
“At the lowest application rates of 75kg N/ha, NBPT-NPPT urea produced 4,106 kg DM/ha and 4,022 kg DM/ha for CAN. Similarly at the highest application rates of 450 kg N/ha, NBPT-NPPT urea produced 5,290 kg DM/ha and CAN produced 5,009 kg DM/ha.”
Figure 1: Herbage produced (kg DM/ha) under plot trials at Moorepark, Clonakilty and Athenry
Further results from this study will be released once available and additional insights will be discussed at the upcoming Teagasc Moorepark Open Day, taking place on Wednesday, July 2.