There is no doubt that protected urea was in the spotlight in 2024 when growth rates on farms were well back on recent years.

Many farmers across the country are left questioning the amount of protected urea they will purchase for the upcoming grazing season.

Grass growth was certainly back from recent years in 2024 with wet conditions experienced in early spring, followed by cold, dry weather in the summer months which left it difficult for grass to take off.

Nationally, grass production was down by 1.1t dry matter (DM)/ha to 11.3t DM/ha in 2024, with large variations across the country.

Rainfall was 142% higher than the average for February, March and April and rainfall in May, June and July was only 81% of the average even though the north-west of the country had above average rainfall for those months.

Although many farmers understood the difficult growing conditions, protected urea was still considered responsible as there was little response to grass growth after spreading.

Another major talking point with protected urea, was how difficult it was to spread the product and get it evenly across the field as many farmers experienced striping in paddocks.

nitrogen fertiliser spreader — Farmers who had the spreader calibrated and serviced were still ending up with striping

Striping occurs when the product is not spread evenly across the field or when the product breaks apart before it reaches the whole distance it is intended to spread to.

Senior research officer at Teagasc Johnstown Castle, Dr. Patrick Forrestal spoke at the Teagasc National Dairy Conference last November and said:

“Protected urea does maintain grass growth when it is compared head-to-head with other forms of nitrogen and it will also reduce emissions which is important for the agriculture sector.”

To get a better understanding, Teagasc reviewed how protected urea performed in different parts of the country which poses the question – should we be putting our trust back in the product?

Protected urea

Teagasc Moorepark researchers, Dr. Brian McCarthy and Dr. Áine Murray highlighted that the clover research experiment showed that the grass-clover sward receiving 150kg nitrogen (N)/ha, produced 11.2t DM/ha which was a 19% reduction compared to the five-year average of 13.8t DM/ha.

On the other hand, the grass-clover sward receiving 150 kg N/ha in the Clonakilty clover research experiment produced 14.5t DM/ha, a 1% increase on the five-year average of 14.3t DM/ha.

Both of the experiments received protected urea (urea + NBPT) for all of their straight N requirements over the last number of years.

Two farms receiving the same amount N throughout the year and both using protected urea showed a grass growth difference of 3.3t DM/ha.

This shows that the geography of the sites, the weather, the conditions and the soil moisture and temperatures, influenced the amount grass grown, not the product.

There were plots in Clonakilty and Moorepark in 2024 that showed little difference between calcium ammonium nitrate (CAN) and urea +NBPT, in a grazing scenario, in terms of pre-grazing yield and annual grass production which can be seen in the table as follows:

N rate (kg N/ha)	120 kg N/ha		200 kg N/ha
Fertiliser type	CAN	Urea + NBPT	CAN	Urea + NBPT
Pre-grazing yield (kg DM/ha)	1,483	1,449	1,728	1,661
Cumulative yield (kg DM/ha)	10,560	10,702	12,221	11,883

The poorer growth rates in Moorepark which were evident from the study were due to the soil N mineralisation being reduced by 30kg/ha due to the poorer weather.

2024 was certainly a tough grazing year but based on the ongoing studies, there was little difference in the grass response from urea + NBPT compared to CAN.

It is hard to tell farmers to consider it, with all the pressure experienced last year, but it definitely should be considered.

In my personal experience, on the farm at home, protected urea proved to be a struggle for us, in terms of getting a response in grass, but, being located in Kildare, we had a very dry summer and the soil struggled to reach high temperatures.

Like a lot of farmers, striping was also an issue on the farm, and in my opinion, to instill trust for protected urea among farmers, there needs to be a solution to this problem of getting an even spread.

While Teagasc has proved that once the product is in the ground, it is possible to get the same response as CAN, the problem for most farmers is getting protected urea in the ground evenly across a paddock.

On many farms, spreading calibration might have to be adjusted to rectify spreading difficulties as different products have different granule sizes and densities.

However. farmers who carried out tray tests and got their spreader vanes right still ended up with striping and an uneven spread.

Protected urea

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Should farmers put their trust back in protected urea?