Frequently Asked Questions

Search our collections of FAQs for answers to common queries or concerns

What is the Yara Grassland Rule?

The Grassland Rule is a rule of thumb to determine the time between N application and optimum cutting interval.

Grass will often take up N more quickly than it can incorporate it into proteins, this is known as 'luxury' uptake. If grass is cut and ensiled before all the nitrogen has been used this is not only inefficient and wasteful but can lead to poor quality silage which livestock may reject. The Grassland Rule states that grass uses N at the rate of 2.5 kg N per per day (2 units N per acre per day) and this should be used to determine the cutting interval. 

Find more information on Yara's Grassland fertilizer programmes.

Can I use a conventional farm sprayer to apply liquid fertilizer?

You can use your conventional farm sprayer to apply liquid fertilizers, however you will need to fit suitable nozzles or stream bars.

Can you supply liquid fertilizer tanks?

Yara supply a range of GRP storage tanks.  Delivery can often be very quick and you could be applying liquid fertilizer in a matter of days after deciding to switch to liquid.

Further details can be found in the Liquid Fertilizer Storage brochure.

What grades of liquid fertilizers can you supply?

Over 500 different grades of liquid fertilizer are available and only the most popular of these are listed in our literature or on the website.

For more information on specific grade availability please contact a member of our Liquid Fertilizer Sales Team.

Find more information on all aspects of liquid fertilizers in the Yara Liquid Fertilizer Brochure.

Do liquid fertilizer storage tanks need bunding?

If a tank is sited according to the industry code there is no need to bund the tank, although bunding is a sensible precaution where possible. Yara area managers will be happy to advise on tank installations.  

There is more information on storage of liquid fertilizer in the fertilizer information section.

How do I avoid scorch from liquid fertilizers?

Any product sprayed onto crops can potentially cause some scorch if applied to a stressed crop. To avoid this do not apply to stressed crops or under hot condition in bright sunlight. Typically early morning or evening are the safest times. 

Can other products be tank mixed with liquid fertilizers?

A wide range of crop protection products and micronutrients can be tank mixed with Yara foliar liquid fertilizers - Chafer Nufol and Chafer Nufol + S. 

Details of compatible tank mixes can be found at or with Yara's TankmixIT app.

What are the advantages of compound fertilizers over blends?

The main advantage of a compound fertilizer is that all the nutrients are contained in each granule or prill.  This means that there is no risk of segregation of the different nutrients during handling or loading as can often occur with blends. Each prill or granule has a uniform size, shape and density which means they can be easily spread uniformly across the whole bout width, unlike blends where there is inevitably a compromise when it come to spreader settings. The advantage of this a much more uniform and even distribution of all the nutrients across the field avoiding under or over fertilization leading to increases in both crop yield and quality.

Watch this short video for more information on the benefits YaraMila compound fertilizers.

How often should I calibrate my fertilizer spreader?

Fertilizer spreaders should be checked and calibrated prior to each application season. A separate calibration should be performed for each different grade of fertilizer. Fertilizer spreader manufacturers may supply spreader settings for different grades however these should always be checked with a tray test calibration.

How long should animals be kept out of fields after fertilizer application?

It is advised to keep cattle, horses and ponies or other livestock out of fields and paddocks until granules or prills have fully dissolved and are no longer visible. If sufficient moisture is present fertilizer granules or prills will typically dissolve in 3-4 days, often much sooner, but under dry conditions relying on soil moisture and dew this can take longer. Any spillages especially near gateways or where refilling the spreader could represent a particular risk and should always be cleared up to avoid direct ingestion. 

Where can I find information on storage requirements for fertilizers?

General information on the best practice for the storage of fertilizers can be found on the Storage of fertilizers webpage and on the Safe use of fertilizers webpage.

Specific information on the legislative requirements when storing ammonium nitrate can be found on the NAMOS regulations webpage.

The AIC have recently published a booklet on The Storage, Handling and Transportation of Ammonium Nitrate-Based Fertilisers which can be downloaded from the AIC website.

Which Yara fertilizers can be spread over 36m using a spinning disk spreader?

All Yara fertilizers are manufactured to high quality standards and most are capable of being spread over 36m however this depends on the spreader being correctly set up and calibrated according to the spreader manufacturers instructions. 

Before spreading any fertilizer a tray test must be conducted especially over wider spread widths.

Why do some fertilizers contain selenium?

Selenium is not required by plants however it is a vital nutrient for human and animal health. Selenium deficiency in livestock is linked to a number of conditions including reduced fertility, increased mastitis and white muscle disease. 

When selenium is included in grassland fertilizers it is taken up by the plant and incorporated into leaf tissues which can then be ingested as either grazed or conserved forage. An advantage of ingesting the selenium in forage is that it is absorbed by the animal more readily than selenium from mineral supplements or boluses which tends to be readily excreted. 

Here are the results of several grassland trials and studies showing the effectiveness of increasing selenium levels in forage with selenium containing fertilizers.

The Booster range of grassland fertilizers all contain appropriate rates of selenium with grades available for most situations.

How can I tell if my crop has a micronutrient deficiency?

It is often hard to diagnose a micronutrient deficiency in the field as often a crop may be struggling with a deficiency before symptoms are visible.

If you suspect a micronutrient deficiency the Yara CheckIT app or the deficiency webpages within each crop section on this site can be used to compare any symptoms with libraries of deficiency photographs. 

The only certain way to diagnose or confirm a micronutrient deficiency is to send a tissue sample for laboratory analysis.  Yara Analytical Services offer a full range of soil, leaf, petiole fruit and water analyses and if needed can also offer a 24 hour service for tissue analysis.

Where can I check which other products can be tank mixed with YaraVita micronutrients?

YaraVita micronutrients can be tank mixed with a wide range of crop protection products.  Full details of all compatible tank mixes can be found using the Yara TankmixIT app and at  

If a specific tank mix test is needed this can be requested online and if the test products are in stock can usually be conducted within 24h.

Will the N-Tester give me a nitrogen recommendation?

The latest model N-Tester will give you a variety specific nitrogen recommendation in the field.  Yara recommend using the N-Tester on winter wheat and winter barley at GS 37-39 to help fine tune the final nitrogen application.

All the latest variety calibrations are built in and can be accessed via the menus.  If needed the latest calibrations can be downloaded and installed from the Yara website.

Find more information on the Yara N-Tester in the Yara N-Tester Brochure or in the Yara N-Tester web pages

Can the N-Tester be used to measure the free nitrate content of grass?

The N-Tester measures the leaf chlorophyll content and uses this to determine the nitrogen content.  This is different from 'free nitrate' which is nitrogen that has been taken up by the plant and stored in the leaf but not yet incorporated into protein.

How much does the N-Tester cost to buy?

The N-Tester costs £1,350 + vat to buy outright. (Price correct May 2016)

If you would like to order an N-Tester please send an email to and we will be in touch

Where can I download the latest variety recommendations for the N-Tester?

The N-Tester variety recommendations are updated every year to include newer varieties as more calibration data becomes available.

The latest N-Tester variety recommendations for winter wheat, winter barley, triticale and rye can be downloaded N-Tester web page.

For the newer model there is a link to download the latest software version and for older models there is a link to download an excel worksheet.

Can the N-Tester give a late recommendation for protein on milling wheat?

There is no link between the N-Tester reading and the level of nitrogen (Nufol) to apply for protein. The N-Tester is aimed at providing a recommendation for final nitrogen applications to achieve optimum yield. 

What the N-Tester will do with continued monitoring is tell you how much nitrogen the crop is able to pick up and will help identify what is happening in the plant. The most important starting point for achieving milling protein spec is to get the nitrogen right for yield. Wheat crops remobilise nitrogen from the leaves to the grain during flowering, but this does not start until mid-flowering, therefore if, through weekly N-Tester reading, you identify levels of nitrogen in the plant falling prior to this time, it can help to identify shortages in nitrogen which will need to be rectified prior to applying the Nufol for protein. As this is likely to be beyond the GS45 cutoff, the absolute recommendation will not be relevant, however something would be beneficial to ensure the crop is optimally fed. 

If the nitrogen levels continue to increase, or remain flat, then you can be more confident of optimal nitrogen rates, and therefore just go with the standard Nufol application at the standard timing.

What crops can the N-Tester be used on?

The N-Tester has only been calibrated in the UK for use on winter cereals - winter wheat and winter barley as well as winter oats and winter rye - On these crops can be used to determine the nitrogen status of the plant and from this a variety specific nitrogen recommendation can be calculated. 

In theory N-Tester could be used on any plant to measure the chlorophyll content of the leaf and as such could be a useful management tool, however, no other crop calibrations exist so these would need to be developed locally by the user and any recommendations would need to be confirmed by locally conducted trials.

What is the Yara quality guarantee?

Over the years Yara has conducted a number of surveys investigating the quality of blended fertilizer products available to farmers in the UK. Results continue to show a significant percentage of analysis failing to meet statutory declared levels and that bags are underweight. 

Yara has always set the standard for quality with Yara’s bags of granular and prilled complex compounds branded with the YaraMila™ logo, the quality mark guaranteeing the product is a ‘true uniform compound’. 

To quote a phrase we have used for many years to describe Yara products:
“What’s on the bag is in the bag!”

What is the blended fertilizer survey?

Over the years, Yara has commissioned a number of surveys to investigate the quality of blended fertilizer products available to UK farmers. 

This is the third time Yara have undertaken this survey and unfortunately the results haven’t changed. Our results show a significant cause for concern with the quality of blended fertilizers. 

How was the research undertaken? 

We bought several tonnes of 23 different blended fertilizers. Bags were selected at random. Each product was sampled, weighed and its packaging audited by an independent expert. Yara’s blended fertilizer was included in the tests and bags were similarly selected at random. Everything was tested and analysed by an independent auditor to secure accurate results. 

What was tested? 

Nutrient analysis – all bags of fertilizer carry a declaration of its contents. We were testing to see if what was stated on the bag, was actually in the bag. 

Weight – you buy a quantity of fertilizer and trust that that is what you receive, so we wanted to check the weight of the bags. 

Packaging – the durability of the bags was tested to see how rugged they were. 

Traceability – can your fertilizer be traced back to the raw material source? 

What were the results? 

64% of bags didn’t contain the nutrients stated on the bag 

36% bags tested were underweight 

46% bags had inappropriate packaging 

59% bags couldn’t be traced to source

What does this mean for you? 

We all want a good deal and you no doubt shop around to make your money go further. But the best deal is not always the cheapest. Unfortunately, our results show that you may be buying a blended fertilizer that under-delivers in the following ways: 

  • You rely on the nutrient declaration stated on the bag. What if that’s incorrect and you’re applying the wrong nutrients to your crops? You could be sacrificing crop quality and yield. 
  • You may be overpaying for your fertilizer because you’re being short-changed on the quantity of fertilizer actually in the bag. 
  • If the packaging isn’t thick enough, you may end up losing fertilizer through bags ripping too easily or water getting in. High quality packaging protects your investment. 
  • Traceable fertilizer keeps us all safe, and increases the quality of fertilizer. If you know what’s going in to making it, you know what you’re putting on your field. 

A cheap fertilizer, can end up being quite expensive. With Yara, quality is guaranteed: 

  • We produce our own fertilizer so everything is traceable to source and we know exactly what we’re putting into our bags 
  • We’ve heavily invested in technology to monitor how much we’re putting into our bags, removing dust and debris and blending the right quantity of nutrients. 
  • Our bags are highly durable to protect your fertilizer so you suffer no wastage.

Where can I find the results of the latest blended fertilizer survey?

Further information on the latest survey can be found on the blended fertilizer quality webpage.

A summary of the results of the latest survey can be downloaded from the 2015 Blender Survey webpage