Our Organisation Search
Quick Links
Toggle: Topics

Greener fertiliser technology delivers both cost savings and reduces GHG’s

Mark Plunkett, Teagasc, Johnstown Castle

Protected Urea is very welcomed news for Irish agriculture as it is a key technology for the sector in meeting its 25% reduction in GHG’s emissions by 2030. It is seldom that a new technology costs less and delivers major environment benefits in reducing N losses. Extensive research in Teagasc and on farm use has shown the reliability of protected urea as a very effective N fertiliser source for Irish farming conditions. It delivers consistently on yield compared to nitrate based fertilisers (CAN 27% N) while significantly reducing nitrous oxide (N₂O) a powerful GHG and ammonia (NH3) emissions thus improving the efficiency of applied fertiliser N.

Urea fertiliser is the most widely used N source in the world and protecting it with a urease inhibitor (NPBT / NPPT) firstly reduces ammonia N (NH3) losses by up to 80% thus retaining more N to better match crop N demands during the growing season. Secondly, by replacing nitrate-based fertilisers (e.g. CAN) with protected urea we reduce N₂O losses by 70%. This is a major ready to go technology in meeting out 2030 target, delivering a 3 to 8% reduction in GHG emissions on livestock farms.

Cost savings €€€!

Over the last 24 months fertiliser N prices have reach heights never seen before due to global unrest. This has resulted in a large price differential between protected urea and CAN, with urea significantly better value due to large volumes traded globally. Over the last 6 months, fertiliser prices have dropped month by month but remain high compared to pre global unrest. Average fertiliser prices to date in 2023 (table 1) show that Protected urea offers a 30% lower cost per kilo compared to CAN (27% N). Take a 50ha dairy farm applying 210kg N/ha as Protected Urea compared to 150 kg N/ha as CAN gives a saving in fertiliser N costs of €7,980.

Retaining more effective N & Reducing N rates

Protected urea reduces N loss from 15% for standard urea to 3% thus retaining 12% more effective N.  With reduced and more regulated chemical fertiliser N use, retaining more effective N in the soil allows adjustments to N rates while still maintaining yield compared to standard urea.  Take an example 50ha dairy farm switching from applying 210kg N/ha as all Standard Urea to Protected Urea, N rates can be reduced by 12% equating to a reduction of 22kg N/ha giving a fertiliser farm N saving of €1,936.

Reducing farm emissions

By switching to 100% protected urea on dairy farms, total farm emissions have the potential to be reduced by 7-8% at a spreading rate of between 200 to 250 kg N / ha. The equivalent savings on total emissions on suckler farms is 1-2%, at a spreading rate of 60 to 80 kg N / ha. To achieve a 100% switch to protected urea the use of high P-K products such as 18-6-12 +S would be required to deliver balanced P, K & S nutrition. On-going research at Johnstown Castle is showing that fertiliser blends containing N with a high ratio of ammonium-N to nitrate-N (generally high P blends) are more stable and environmentally friendly.   For example, the N form is 10-10-20 / 18-6-12 is mainly ammonium N resulting in a 40% reduction in N₂O emissions relative to CAN 27% N or  high Nitrate – N based compounds such as 27-2.5-5 / 24-2.5-10.

More grass from less N

A long-term trial (8 years) at Johnstown Castle is consistently showing that the grass grown by protected urea has been greater than standard urea in 7 out of 8 years.  Protected urea grew 13% more grass on average compared to standard urea.  The additional yield is similar in magnitude to the extra effective N level delivered to the plant by protected urea over standard urea. CAN yielded 9% more than standard urea.  At a time of more regulated chemical fertiliser N use moving from standard urea to protected offers the opportunity to reduce fertiliser N rates by up to 10%.


Figure 1:- Long-term trial at Johnstown Castle shows that protected urea grows more grass in 7 out of 8 years.

In Summary - Making the switch to Protected Urea delivers the following

  • Reduce your fertiliser N costs by 30%
  • Reduce N₂O & NH3 emissions by 70 and 80%, respectively
  • Reduce overall farm emissions by 7 to 8%
  • Fertiliser blends such as 18-6-12 reduce GHG emissions by 40%
  • Reduce farm N requirements (Switch from Standard Urea to Protected Urea)
  • Protected urea grows 13% more grass over standard urea