Top tips to get more from urea this spring

Rising demand, supply concerns and global trade tensions led to urea price rises of over £40/t during March, with some commentators suggesting prices could continue to climb.

As growers prepare to apply spring nitrogen, BASF’s technical specialist for nitrogen management, Andrew Clune, gives his top tips for getting the most from urea applications, while also reducing losses to both air and water.

1. Protect your urea

Using urea protected by a urease inhibitor minimises volatilisation and keeps nitrogen in the soil where plants can access it.

Andrew says, “it’s not only good for the environment, but also for your bottom line.

Whether you’re applying urea to arable crops or grassland, multiple independent trials, both in the UK and Ireland, have demonstrated a valuable uplift in yield.”

Across six replicated trials conducted by ADAS, Limus^® protected granular urea outperformed unprotected urea by an average of 5%, increasing winter wheat yields by 0.5t/ha (figure 1).

While in a Teagasc (Ireland) trial, Limus® protected urea increased grassland dry matter by 1,500kg/ha (figure 2).

Figure 1

Figure 2

Andrew explains, “these yield increases are a result of plants being able to uptake nitrogen that would usually be lost to the environment – a threat to both air and water quality as well as contributing to climate change.”

Only 50% of applied nitrogen is taken up by plants.  The remainder is converted into ammonia, nitrates and nitrous oxide, which have the potential to be lost to both watercourses and the atmosphere.

See how Limus^® compares to untreated urea in blocking the breakdown of urea, preventing ammonia losses and optimising Nitrogen use efficiency.

Atmospheric losses from ammonia can have an effect on the natural environment, but also impact human health.

“It is why governments have put mechanisms in place to increase the use of urease inhibitors,” adds Andrew.

The scrutiny of urea use is increasing, in England, compliance with the Red Tractor guidelines is being monitored and Defra is comparing urea sales with those of inhibitors, as well as measuring the amount of ammonia in the air.

Andrew says, “ignoring the guidelines and applying unprotected urea after 1^st April, could have ramifications for the whole industry.

“The door is wide open for the government to reconsider the options that were on the table when they did the first round of industry consultations.”

In Ireland, further restrictions on unprotected urea are already becoming a reality, after confirmation that measures will be coming into place from 15 September 2025.

“Ultimately, using a protected urea like Limus, is good for your crops, your business and the wider agricultural sector.”

2. Choose the most effective product

Limus^® is the only urease inhibitor available with two active ingredients – NBPT and NPPT which enables it to bind to the active sites of a wider variety of urease enzymes (figure 3), temporarily inhibiting their ability to convert urea to ammonia and carbon dioxide.

This makes Limus^® more effective in protecting urea from ammonia volatilisation.

Andrew says, “urease is produced by a wide range of organisms, including bacteria, fungi, algae, plants, and invertebrates.

“Urease enzymes are found both intracellular (within soil microorganisms) and as an extracellular protein associated with organic matter decomposition and nutrient cycling in the soil.

“It is important to note that Limus works on the urease enzymes that microorganisms produce, not on the microorganisms themselves.”

The product is highly effective. Across 93 BASF field trials, Limus^® proved to reduce ammonia emissions by up to 98%. Similar results have been seen in the laboratory.

Andrew adds, “We have extensively tested the efficacy of Limus^®. Time and time again it has proven its strength as a highly effective urease inhibitor.”

In a further 74 BASF trials, Limus^® raised the yield performance of granular urea to the level of ammonium nitrate and calcium ammonium nitrate.

“The combination of two active ingredients, along with a multi-patented, innovative formulation makes Limus the most effective urease inhibitor available.”

Limus^® protected solid urea is available only from Thomas Bell (Diamond Fertilisers), Bartholomews Agri Food Ltd, and COFCO. BASF work closely with each to ensure Limus^® is applied to reliable and high-quality urea.

Figure 3: Limus is the only urease inhibitor with two active ingredients – NBPT and NPPT – increasing the range of urease enzymes it inhibits

3. Consider timings and accuracy of applications

While the widespread use of urease inhibitors is relatively new, their inclusion doesn’t change how the performance of urea is optimised.

Timing applications with rainfall or irrigation will help wash urea into the soil and buffer the resulting pH spike. It will minimise volatilisation and further contribute to keeping the nitrogen where plants can use it.

Andrew adds, “being able to store your protected urea makes timing applications just that little bit easier. Many products have a relatively short shelf life, but Limus is stable at 20^oC for more than 12 months.”

Andrew acknowledges that incorporating urea into the soil is another way to minimise volatilisation but notes that tillage isn’t always practical.

“Paying attention to the detail is key. Fertiliser spreading is precision work and getting it right results in more even crop development that is both easier to manage and to harvest.”

Andrew also highlights the need to calibrate spreaders, use the correct settings and ensure applications are made in suitable weather conditions.

To find out more about Limus, visit www.agricentre.basf.co.uk/limus