Protected Urea – why now?

Teagasc research has shown that protected urea nitrogen fertiliser offers the single largest emission reduction potential to Irish farmers. Researcher Patrick Forrestal and advisor Cathal Somers give more information

The challenge our industry faces and why protected urea now?

The challenge to reduce emissions on farms has never been greater. To meet this challenge while continuing to produce farmers need practical tools which allow progress towards reducing emissions. Of the tools assessed by Teagasc, protected urea nitrogen fertiliser offers the single largest emission reduction potential to Irish farmers as they seek to reduce a greenhouse gas (GHG) and ammonia emissions without impacting production. Protect urea is also a cost effective option so it is a win-win for the industry.

What is urea protected from?

Urea N is protected from ammonia gas loss, the traditional weakness of urea. Urea can lose some of the applied N as ammonia gas. If ammonia-N is lost it can’t grow grass where you spread it. Teagasc research shows protected urea consistently matches CAN yield performance; this is because the protection safeguards the urea-N from loss as can be seen in Figure 1. In addition protected urea by not adding large amounts of nitrate directly to soils gives an important reduction in the greenhouse gas nitrous oxide in grasslands which the industry can get credit for. 

Figure 1. Protected urea (left) vs urea (right). The blue colour change indicates ammonia-N loss

How is the urea protected?

Urea can be protected using a urease inhibitor either coated onto the outside or incorporated into the urea granule during the manufacturing process. There are three registered regulated urease inhibitors and Teagasc have conducted research on them. These are:

1. NBPT+NPPT
2. NBPT
3. 2-NPT

The current Teagasc list includes 18 options from 6 fertiliser manufacturers/blenders. To keep up to date on new protected urea information refer to the Teagasc Protected Urea webpage

Updated 20th December, 2019

Traditional N use and how protected urea fits in

Nitrogen (N) fertiliser plays a key role in achieving high grass yields, particularly in ryegrass swards. Traditionally, farmers have used ordinary urea in early spring when temperatures are cooler, switching to CAN as the season advances. Compounds have been used as needed to deliver N-P-K. So how does protected urea fit in? Protected urea can be used in any of the straight N/ N+S slots where a farmer currently uses urea or CAN i.e. it can be spread throughout the growing season. Where a farmer needs a compound he should continue to do so. For example, using 18:6:12 for a round in spring is recommended on many soils to ensure P, which is poorly available in cool spring soils is available to the grass. In addition this compound will help to maintain soil K levels. Continue to use traditional compounds as needed.

Tips

• Protected urea has a lower density than CAN and compounds, adjust spreader settings accordingly, consult your spreader manual/supplier for details. If you already spread urea accurately you should be able to spread protected urea accurately
• For the greatest protection level use protected urea within 12 months as the urease inhibitor will degrade over time in storage
• Potassium and sulphur mixes with protected urea can be purchased, however currently phosphorus (P) blends result in shelf life problems for the protection. Consult the Teagasc Protected urea fertiliser list above
• Consider in using in your straight N or N+S slots, if P&K needed use a traditional compound