Introducing Limus A4 Brochure_FINAL 2019

Introducing Limus ®

If you want to stop profits escaping, start by choosing Limus ®

Why is your nitrogen up here?

When it can be down here.


Nitrogen losses

Nitrogen losses


Only 50% of applied nitrogen is taken up by crops. Nitrogen losses can occur in the form of ammonia, nitrate leaching and the release of nitrous oxide into the atmosphere. While nitrogen losses generally result in an economic cost on farm, they also have a negative impact on the environment.

Ammonia volatilisation


Ammonia losses Significant ammonia losses can occur after the application of urea-based fertilisers. Ammonia is an air pollutant. A key component of smog, it binds with other pollutants and particles in the atmosphere, leading to negative impacts on human health. It is carried long distances by wind and brought down with rainfall, acting as a nitrogen fertiliser far from where it was intended and damaging sensitive natural habitats. Nitrate leaching Nitrate is highly mobile in the soil. After heavy rainfall or low plant uptake, nitrate can leach out of the soil profile and accumulate in groundwater, which can be toxic if threshold limits are exceeded. Nitrate in surface water bodies stimulates water plant and algae growth. As algae and/or water plants decay, the resulting oxygen depletion may, under extreme conditions, lead to mortality in fish populations.


Urease inhibitors



Introducing Limus ®

Limus ® benefits


Ammonia and legislation


Increase in nitrate

New to the UK market, Limus ® is a unique and highly effective urease inhibitor from BASF. Limus ® protects urea-based fertilisers, minimising nitrogen losses from volatilisation and ensuring optimal nitrogen is available for your crop.

Nitrous oxide losses Nitrous oxide occurs during nitrification

Climate change

(conversion of ammonium into nitrite and nitrate through soil bacteria). Next to carbon dioxide and methane, nitrous oxide is one of the most dangerous greenhouse gases. Its global warming potential is 298 times that of carbon dioxide. Even small nitrous oxide losses may represent a cost factor to growers as well as a negative environmental impact.

• Reduces ammonia emissions by up to 98% • Increases application timing flexibility

• Improves yield by 5% compared to unprotected urea/UAN • Raises performance to the level of ammonium nitrate • Outperforms all other urease inhibitors



Nitrogen losses

Nitrogen losses from ammonia, nitrate and nitrous oxide all occur at different stages of the nitrogen cycle. All nitrogen fertilisers are subject to some degree of loss, no matter the source, and innovative technologies can help minimise these losses.

Urease inhibitors

Nitrification inhibitors

Urea/UAN application

Slurry or mineral ammonium application

Average ammonia losses

Average nitrous oxide losses

~ 20%

~ 1%

- 98%

- 50%



Nitrate Plant available




Urease Enzymes



Plant available (limited)

Plant available

- 35%

~ 25%

Limus ®

Vizura ®

Average nitrate losses

How do nitrogen losses occur? Hydrolysis: Urea fertiliser has limited availability to plants. It must frst go through a process called hydrolysis, where urease enzymes convert it to plant available ammonium. During this process, some of the ammonium can be lost as ammonia through volatilisation. Ammonia: Ammonia losses from urea based fertilisers can be up to 80% of the total applied nitrogen, depending on the urea fertiliser type, climate and soil pH value. In the UK, the DEFRA funded NT26 project concluded that around 20% of applied nitrogen from granular urea is lost as ammonia. For UAN these average losses are around 14%.

Nitrification: Ammonium, either from hydrolysis or following application of ammonium nitrate or slurry, is plant available and can be taken up and metabolised easier than nitrate. However, ammonium is rapidly converted into nitrate during a process called nitrifcation. Nitrosomonas bacteria in the soil change the ammonium to nitrite, which then gets converted into nitrate by nitrobacter. Nitrate: Nitrate is negatively charged so no longer binds to the soil. Water can then transport it down the soil profle out of reach of the roots. Typically, nitrate leaching is worse in the winter when the soils are at water holding capacity. On light soils, leaching can occur in the spring following a heavy rainfall event.

Nitrous oxide: Nitrous oxide can also be given off during this process. Although typically only 1% of applied nitrogen is converted to nitrous oxide, it is a powerful greenhouse gas, 298 times more potent than carbon dioxide. Therefore contributes signifcantly to agricultural greenhouse gas emissions. How can technologies reduce nitrogen losses? Urease inhibitors: Urease inhibitors slow down the hydrolysis process, minimising losses from ammonia. Limus ® reduces ammonia losses by up to 98%, making more nitrogen available to crops.

Nitrification inhibitors: Nitrifcation inhibitors inhibit the Nitrosomonas bacteria, preventing the conversion of ammonium to nitrite. The use of a nitrifcation inhibitor like Vizura ® , reduces nitrous oxide emissions by around 50% and leaching by around 35%.

Only 50% of applied nitrogen is taken up by crops.



Ammonia volatisation

Urease inhibitors

Urease enzymes Urease enzymes are produced by plants and microbes in the soil. They have an active site that can bind urea. Once urease and urea are bound, the urease enzyme transforms urea into ammonia and carbon dioxide. If the urea has not been washed into the soil, this results in ammonia volatilisation. When ammonia and carbon dioxide leave the active site, the site is free to once again convert (hydrolyse) another urea molecule and the process can start over again.

How to reduce ammonia losses There are three main ways nitrogen losses from ammonia volatilisation can be minimised: 1. Rainfall or irrigation (> 10 mm) : Suffcient rainfall or irrigation will help wash the urea into the soil and buffer the pH spike, hence minimising volatilisation. However, considering the last couple of dry springs, ensuring a suffcient rain event shortly after application can be a challenge, whilst irrigation isn’t feasible for the majority of UK crops. 2. Incorporation (tilling > 10 cm) into the soil: Incorporation also helps minimise volatilisation. However, for winter crops, where sowing and fertilising are conducted in different seasons, tilling is not practicable. 3. Urease inhibitors: A reliable and pragmatic way to consistently reduce ammonia losses is to use urea-containing fertilisers with a urease inhibitor. How urease inhibitors work Urease inhibitors (eg. NBPT) temporarily inhibit urease enzymes from converting urea into ammonia - until the urea has been suffciently washed into the soil. They do this by binding to the urease enzyme, preventing urea from binding to the active site, delaying the hydrolysis process and hence minimising volatilisation.

Urea binds to the urease enzyme

Active Site


Urease enzyme

The urease enzyme releases the ammonia and carbon dioxide

The urease enzyme transforms urea into ammonia and carbon dioxide

(NH 3


(CO 2


Ammonia (NH3) volatilisation

Ammonia (NH3)

Carbon dioxide (CO2)

NBPT blocks the urease enzyme, slows down urea hydrolysis and hence ammonia volatisation.

Standard urease inhibitor

Volatilisation Urea granules are hygroscopic meaning they absorb moisture from the air and can begin to move into the soil even in the absence of rainfall. Once moisture is present, the urea is no longer stable. It’s at this point the urease enzymes start the hydrolysis process, converting urea into ammonium. As ammonium is alkaline, this conversion process temporarily raises the pH of the soil around the urea granule. If the pH spike is not buffered by rainfall, it results in ammonia volatilisation.

Urea granule

pH 8.5

Standard urease inhibitor



Urease enzyme

Urease enzyme

Different urease enzymes require different urease inhibitors​

pH 6.0

The challenge with standard urease inhibitors​ Soils differ in their urease enzyme composition and urease activity. A broad range of organisms in soil (bacteria, fungi and plants) all produce slightly different urease enzymes. These different urease enzymes require different urease inhibitors, meaning some will remain active despite the use of a standard urease inhibitor.​

Ammonia loss is a localised reaction​



Introducing Limus ®

Limus ® reduces ammonia emissions by up to 98%

Limus ® is a highly effective and unique, dual-active urease inhibitor from BASF, available as both protected urea and as a tank mix additive for UAN

Nitrogen use efficiency Reducing ammonia losses allows the applied urea nitrogen to work more efficiently and enhance nitrogen nutrition. This often leads to higher yields or nitrogen fertiliser savings, as well as an improved environmental footprint. Limus ® is the most effective solution for the reduction of ammonia losses and for increasing nitrogen uptake by plants from urea containing fertilisers. Reduction of ammonia emissions We have extensively tested the effcacy of Limus ® in both laboratory conditions and in the feld, and time and time again it has proven its strength as a highly effective urease inhibitor, reducing ammonia emissions by up to 98%. In the feld, closed chamber devices with acid treated foam are used to measure ammonia emissions. Across 93 BASF trials, up to 98% reduction was achieved with an average reduction of 70%. Whilst in the laboratory, we have assessed its performance on a range of different soil types. Reductions of up to 98% were also achieved with an average reduction of 83%.

The most effective urease inhibitor Limus ® is the only urease inhibitor available with two active ingredients (NBPT and NPPT), enabling it to bind to a wider variety of urease enzymes, compared to a standard urease inhibitor, thus more effectively protecting the urea from ammonia volatilisation. This dual-active combination, along with a multi-patented, innovative formulation makes Limus ® the most effective urease inhibitor available.





Urease enzyme A

Urease enzyme A

Urease enzyme B

Urease enzyme B

Why Limus ® ?

Tried and trusted globally since its market introduction in 2015, Limus ® brings a wide range of benefts to growers.

Improves yield by 5% compared to unprotected urea/UAN

Raises performance to the level of ammonium nitrate

Reduces ammonia emissions by up to 98%

Increases application timing flexibility

Outperforms all other urease inhibitors

For information on Limus ® suppliers, please visit

Limus ® for granular urea BASF has partnered with a number of urea importers who will apply Limus ® , a liquid formulation, to their urea granules. Look out for ‘Contains Limus ® ’ when purchasing.

Limus ® for liquid urea Limus ® Clear is for use with liquid urea containing fertilisers. It is available as a standalone product to be tank mixed with the fertiliser on farm shortly prior to use.

Closed chamber devices with acid treated foam



Limus ® increases application flexibility

Limus ® improves yield by 5% compared to unprotected urea/UAN

ADAS trials

In a comprehensive set of replicated trials carried out by ADAS, we looked at the performance of Limus ® protected urea versus unprotected granular urea, ammonium nitrate and a competing urease inhibitor. Six different sites were identifed across the country that offered a range of different soil types and feld conditions.

High Mowthorpe






Relative yield increase (%) of Limus ® vs. unprotected urea

ADAS results

Across the six replicated trials, the results mirrored our extensive global data set. At a rate of 260kg/ ha N, Limus ® protected granular urea outperformed unprotected urea by an average of 5%, increasing yields by 0.5t/ha. Yield differences varied, most likely reflecting the extent of ammonia emissions at each site. Limus ® safeguards your investment from such losses, ensuring optimal nitrogen is available for your crop.




Urea based fertilisers should be applied shortly before rainfall in order to reduce ammonia losses from volatilisation. Traditionally, higher rates are used, or additional applications are made, to compensate for the losses that can often occur in our unpredictable maritime climate. Limus ® protected urea fertilisers can be applied independent of weather conditions as they effectively prevent these losses. This not only simplifies fertilisation programmes considerably, it also allows for greater exibility and a more effcient use of resources.


Urea + Limus ®

Source: ADAS/BASF, UK, winter wheat, n=6, 260kg/ha N in 3 application splits

Relative yield increase (%) of Limus ® vs. unprotected urea/UAN

Application of urea without Limus ®

Application of urea with Limus ®

BASF results

We have been extensively testing the yield performance of Limus ® in the feld for a number of years, across a range of crops. Across 107 BASF trials, Limus ® protected urea/ UAN improved yield by an average of 5%, demonstrating that the reduction in losses achieved with Limus ® ensured greater availability of nitrogen for uptake, resulting in higher yields.




Flexible fertilisation period application

Urea/UAN + Limus ®


Source: BASF, range of crops, n=107



Limus ® raises performance to the level of ammonium nitrate

Limus ® outperforms all other urease inhibitors

NT26 project


As part of the wide-ranging DEFRA funded NT26 project, the performance of the urease inhibitor, NBPT (one of the active ingredients in Limus ® ) was evaluated as an alternative to ammonium nitrate (AN). The project concluded that granular urea plus NBPT matched AN for performance in winter cereals, according to average fgures taken from 10 locations.

As the only urease inhibitor with two active ingredients, Limus ® more effectively minimises ammonia losses, ensuring greater availability for crops and higher yields.

ADAS results

BASF results

Relative yield increase (%) of Limus ® vs. NBPT

Relative yield increase (%) of Limus ® vs. NBPT

Relative yield increase (%) of Limus ® vs. AN

ADAS results

The six ADAS trials reinforced the fndings from the NT26 project, showing a similar yield performance of Limus ® protected granular urea to that of ammonium nitrate. Limus ® raises the performance of urea to the same level as ammonium nitrate by minimising the nitrogen losses from ammonia. In these trials, at the rate of 260kg/ha N rate, Limus ® protected granular urea actually outperformed ammonium nitrate by an average of 1.5%, increasing yields by 0.14t/ha.










Urea + NBPT

Urea + Limus ®


Urea/UAN + Limus ®


Urea + Limus ®

Source: ADAS/BASF, UK, winter wheat, n=6, 260kg/ha N in 3 application splits

Source: BASF, range of crops, n=107

Source: ADAS/BASF, UK, winter wheat, n=6, 260kg/ha N in 3 application splits

Relative yield increase (%) of Limus ® vs. AN/CAN

Storage stability

BASF results

Across 74 BASF trials, Limus ® raised the yield performance of granular urea to the level of ammonium nitrate and calcium ammonium nitrate. These equivalent yields highlight that provided ammonia losses are minimised, urea is as reliable a source of nitrogen as ammonium nitrate.

The stability of urease inhibitors when added to urea can be limited. Limus ® contains our BASF patented polymer technology, providing longer a.i. stability versus generic NBPT and 2-NPT formulations. Even at 20°C Limus ® is stable for more than 12 months, giving confdence that even if purchased a year in advance, Limus ® will still work effectively.




Storage stability on urea 20°C, closed bag


Urea + Limus ®


Source: BASF, range of crops, n=74

Limus ®











Storage time (months)

Source: BASF



Ammonia and legislation

Legislation roadmap

UK agricultural ammonia emissions by management category (2016)

Ammonia emissions and agriculture The agricultural sector accounts for 88% of UK ammonia emissions. 23% of agriculture’s emissions are largely from the application of urea based fertilisers. The UK government is committed to reducing these ammonia emissions from agriculture - along with pollutants from other sources - and in both its 2018 and 2019 Clean Air Strategy document, it advised that legislation might be introduced to support this reduction.

Gothenburg Protocol, 2012

• Abate acidifcation • Eutrophication • Ground level ozone

Hard standings 7%

Sewage sludge application 2%

Grazing outdoors 8%

EU legislation, 2016

• National Emission Ceilings Directive • Ammonia vs 2005 • 2020: -8% (UK) • 2030: -16% (UK)

Livestock housing 27%

Manure storage 9%

Fertiliser application 23%

Manure application 25%

Clean Air Strategy 2018 (UK)

• Proposes the use of urease inhibitors with urea-based fertiliser, unless injected, by 2020 • Will provide a national code of Good

Source: National Atmospheric Emissions Inventory 2018

Legislation The path to UK legislation began in 1999 with the Gothenburg Protocol, designed to reduce acidifcation, eutrophication and ground level ozone emissions, including ammonia. The protocol was then revised in 2012 to include national emission reduction commitments for 2020 and beyond. This was implemented into EU legislation in 2016 as part of the National Emission Ceilings Directive, where countries including the UK and Ireland, committed to signifcant reductions. The UK government has since reaffrmed it’s commitment to these targets in recent strategy documents. It also introduced a Code of Good Agricultural Practice to serve as a guidance document to support reductions, which includes a recommendation to use urease inhibitors. The government is currently seeking consultation on approaches to reduce ammonia emissions. Legislation focusing on urea-based fertilisers is expected, with the use of urease inhibitors one of the main approaches currently being evaluated.

Agricultural Practice to reduce ammonia emissions

Code of Good

• Guidance document for reducing ammonia emissions • Supports the use of urease inhibitors with urea based fertilisers

Agricultural Practice for reducing ammonia emissions (UK)

New Agricultural Bill (UK)

• Financial assistance for delivering clean air and water • Includes reduction of ammonia emissions

Clean Air Strategy 2019 (UK)

• “A requirement to reduce emissions from urea-based fertilisers” • Consulting in 2019

to bring through legislation in the shortest possible timeframe

The UK government is legally obliged to reduce ammonia emissions by 8% by 2020 and by 16% by 2030, compared to 2005 levels

For more information on Limus ® , please visit



For an optimised supply of nitrogen to your crops, please ask your supplier about Limus ® products. For more information on Limus ® , please visit

BASF PLC, Agricultural Solutions, Earl Road, Cheadle, SK8 6PT United Kingdom T: 0161 485 6222

Limus ® is a registered trademark of BASF

Limus ®

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