Protected urea list has some notable exclusions

The Teagasc list of protected urea products, printed in Table 1 has not been updated since it was last published in February 2023. The list contains most of the different fertiliser types on the Irish market which contain protected urea. All of the products on the list contain one or some of the three types of inhibitors favoured by Teagasc; NBPT, 2-NPT+MPA or NPPT.

These are the abbreviations for the type of chemical compound that the urea is coated in prior to being packaged.

This coating is what gives the urea its protection and slows down the conversion of urea to ammonia and as a result reduces the amount of ammonia lost to the atmosphere and increases the efficiency of the nitrogen in urea.

By looking at the list, farmers will know which fertiliser product contains which inhibitor or combination of inhibitors.

For example, if a farmer wants to use NBPT on its own they can selected the Goulding range of protected ureas containing Agrotrain, or if they wish to use NBPT and NPPT together (Limus) they have more of a selection of different fertiliser brands as this is a widely used inhibitor manufactured by agri-chemical company BASF.

Unfortunately for the farmer, that’s more or less where the information flow ends. They don’t know at what rate the inhibitor was applied or when it was applied.

Both of these things are important as the trial work on protected urea inhibitors was conducted at a certain application rate but the word on the ground is that the same application rate is difficult to repeat at commercial stage, because it makes the protected urea too soft.

The date of application is also important as there is a shelf-life on the inhibitor which varies from six to 12 months depending on the brand used. So farmers buying protected urea in February, that won’t be used until April may be buying product that will not be fit for purpose if the inhibitor was applied before the previous November, depending on the product.

There has been no real movement on the date stamping on bags of when the protected urea inhibitor was applied. Most fertilisers have a batch code and this does indicate the year and date of manufacture.

For example, a code such as 2024300. This would indicate that the fertiliser was bagged on 27 October 2024 as 27 October is the 300th day of the year.

However, these batch codes also contain other numbers such as factory code and batch ingredients or batch numbers that day. It can also be extremely difficult or impossible to find the code on a bag and oftentimes the film protecting the bags may obscure the codes.

In short, it is not an open or transparent way of identifying the date that the inhibitor was applied.

There appears to be no real openness from the fertiliser industry around displaying the date of inhibitor application. It should be said that protected urea with an out-of-date inhibitor is effectively the same as ordinary urea.

To be fair, most manufacturers will blend protected urea as close as possible to the peak seasonal demand in order to give the product the longest shelf-life, but many feel that the lack of transparency around date stamping is troubling.

Speaking at the Teagasc national dairy conference last November, researcher Patrick Forrestal encouraged farmers to only purchase protected urea that is on the Teagasc list. Meanwhile, Teagasc have come back this week to say that there is currently no list available, despite the list in Table 1 being distributed at farm walks this spring.

Off list

There are a number of notable exclusions from this list. The first is the Goulding product GEN or Goulding Enhanced Nitrogen. Goulding’s says that the active ingredient in GEN is approved by both the European Union and the Department of Agriculture as a protected urea.

Goulding says that GEN is “tried, tested and proven in Ireland and the UK and is used on 29 million hectares across the world”.

GEN is being sold in Ireland as a protected urea and is considered a protected urea in terms of the national inventory but is not on the Teagasc list.

Another type of fertiliser not on the Teagasc list of protected ureas is liquid nitrogen, specifically acid-treated urea such as N-xt or Flex as supplied by Tom Butler in Tipperary and Tom Breen in Wexford.

These liquid nitrogen products have been acidified by sulphuric and/or phosphoric acid. Using complex technology developed in the Netherlands, they say that their range of fertilisers solves many of the problems encountered by farmers in terms of being able to spread protected urea, adding additional nutrients and keeping fertilisers out of watercourses.

They also cite the approach taken by Denmark, where acid-treated liquid nitrogen is widely used and assigned the same status as protected urea.

Finally, work is ongoing on CAN based inhibitors which reduce the nitrous oxide emissions from applied CAN based nitrogen.

If these products are approved and are affordable, they would provide a reliable alternative to protected urea.