Know how your product spreads before a farmer finds out.
Independent spreading trials and product development for fertilisers, lime, pellets, granules and soil amendments. We can work with a product while you’re still developing it, or validate it once it’s finished, on the spreaders UK farmers and grounds teams use, and give you the settings to send out with it.
Developing a new granular or pelleted product?
A product can work in the lab and still let you down in the spreader. How it flows, how it handles and how evenly it spreads all come from its physical make-up, not its chemistry.
That means granule or pellet size and the spread of sizes, density, shape and surface, strength and how easily it crumbles, fines and dust, moisture, how consistent one batch is with the next and, in a blend, whether the ingredients separate.
Testing while the product is still being developed catches application problems before the specification or the production process is fixed. We test how your product behaves in the spreader; we don’t formulate its chemistry.
What a trial can tell you
- Whether it can be spread with ordinary farm spreaders, and which types suit it
- Realistic working widths, and the settings to start from
- How evenly it spreads, and whether a blend separates
- Whether pellets or granules break down in handling or on the vanes
- Whether a change to the specification makes it spread better or worse
- Whether one prototype or production batch performs like the last
From prototype to the field.
We can run one trial, or work alongside your development programme: test, feed back what we find, and test again after you change the product. Once it’s final, we establish the settings for commercial use.
- Prototype product
- Physical assessmentSize, density, strength, fines
- Initial spreading trialMachines, widths, first settings
- Results and analysisWhat it does in the spreader, and why
- Product or specification changesMade by you, with our findings
- RetestRepeat until it spreads as it should
- Final validationThe finished product, tested independently
- Settings and guidanceFor your customers and your technical literature
Steps 5 and 6 repeat as often as the product needs.
Products we work with.
If it’s a dry product meant to be broadcast or put on with a machine, we can test how it spreads. We don’t trial liquid products.
Fertiliser and lime
Granular, compound, blended and prilled fertilisers; granulated lime, gypsum and calcium products; sulphur granules. We usually start at 24 m, the most common width on UK farms, and 36 m, on both outward- and inward-spinning disc spreaders, then add the machines, widths and discs you need.
Pellets and new granules
Organic and bio-based products, digestate and poultry-litter pellets, recovered and recycled nutrient products, biochar and carbon granules, and soil amendments. We see how they flow and handle, whether they break down in the hopper or on the vanes, and how far and how evenly they throw.
Slug pellets and granular crop protection
Tray tests for working width and left-to-right balance, rate tables for a range of application rates, comparisons with competitor products, and samples collected across the bout for pellet integrity and breakage analysis in efficacy or registration trials run with accredited organisations. The data behind Certis’s slug pellet Calibration Wizard came from our trials.39
Amenity fertiliser and seed
How amenity fertiliser and seed spread through the rotary, drop and handheld spreaders that grounds teams use: working width, left-to-right balance (single-disc spreaders especially), and rate tables for single and double passes, so your customers get clear settings.
Developing something different? If it’s a dry product meant to be broadcast or put on with a machine, talk to us.
Fertilisers and application equipment are continually evolving. To keep ICL at the forefront of the industry, we utilize the service from Spreader & Sprayer Testing to rigorously evaluate our products and provide the calibration data we use every day.
Development trials or independent validation.
Two different jobs. Tell us which you need, or both in turn.
Product development trials
While the product is still being developed. The aim is to learn and improve.
- Several prototypes, and repeated trials
- Changes to the product’s physical characteristics
- Comparisons between formulations
- Working with your technical team
Independent validation
Once the product is substantially final. The aim is independent evidence of how it performs in commercial use.
- An agreed product specification, machines and widths
- A structured trial programme
- A formal report
- Machine settings and application guidance
Trials for importers and suppliers
Bringing a product in, or already selling one? Here’s why each product, and each shipment, is worth a trial.
Most of Britain’s fertiliser now comes in by sea.
Britain no longer makes its own ammonia, urea or UAN. Its one nitrogen plant, CF’s Billingham, makes ammonium nitrate from imported ammonia.1 Even flat out, it could supply only about a fifth of the nitrogen British farmers use.12
The rest arrives cargo by cargo. Most imported ammonium nitrate came from Lithuania and Poland in 2025, and urea from Finland, the Netherlands, Algeria, Egypt, Germany and Nigeria.3 Imported AN no longer sells at a discount: £489/t against £485/t for UK-made AN in the week to 2 October 2026.4 It has to win on how it performs in the field.
| 4.0 million t | Fertiliser imported into the UK in 2025, up 24% on 2023. Nitrogen products made up 2.9 million tonnes.3 |
|---|---|
| Dozens of cargoes | Imported AN lands as separate coaster loads of about 3,300 t, at ports from Plymouth to Invergordon. Each can be a different production batch.3 |
| About 200 | Businesses that imported nitrogen fertiliser in 2025: merchants, co-ops, grain traders and importers.3 |
Import figures are our reading of HMRC trade data, by country of dispatch.
The law checks what’s in the bag, not how it spreads.
UK fertiliser rules set limits on nutrient content, and Defra says that’s all they do.5 A fertiliser can be bang on spec for nitrogen and still spread badly.6 High-nitrogen AN must pass a detonation test, batch by batch, before it lands, but that’s a safety check. Nothing equivalent exists for spreading.7
It hasn’t always been this way. In the 1990s, nitrogen fertilisers could carry an “SP” spreadability rating, tested at Silsoe, and importers asked how to meet it.8 In 2025, Ireland’s Teagasc called for bags to show granule size, density and strength.9 Until something like that comes back, proving a product spreads is down to whoever sells it.
| Checked before sale | Not checked by anyone |
|---|---|
| Nutrient content, within legal tolerances6 | Granule size range |
| Detonation resistance of high-nitrogen AN, every batch7 | Granule strength |
| Safety, security and traceability, under the industry’s FIAS scheme10 | Bulk density |
| How far and how evenly it spreads5 |
Farmers set it from the chart.
When your fertiliser arrives on farm, the farmer looks it up in their spreader’s setting chart or app. If your product isn’t there, they pick the one that looks closest, and hope.
Setting charts come from the spreader manufacturers’ test halls, from samples of the products they’ve tested.1112 A fertiliser’s chemistry is controlled, but its physical make-up isn’t, and that decides how far each granule is thrown.13 Few farmers check: only 6% tray-test the pattern every time they change fertiliser.2 With UK tramlines mostly at 24 or 36 m,14 the width a product reliably reaches is part of what you’re selling.
When a product won’t reach the tramline, or leaves stripes, the farmer is unlikely to blame the chart. When some protected-urea products striped in Ireland in 2024, importers and distributors said they were “inundated with farmer complaints”.15
| 13.6% to 5.1% | The CV of one spreader on its chart settings, then after a tray test. The chart had been drawn up with a coarser product than the batch in the hopper.16 |
|---|---|
| 44% against 8% | Two urea and sulphur fertilisers with much the same nutrients, a blend and a compound with nitrogen and sulphur in every granule, each tray tested at 24 m on the spreader manufacturer’s app settings. The blend gave a 44% CV, the compound 8%. The same chemistry doesn’t mean the same spread.17 |
| 0.75 against 1.0 kg/l | Urea against CAN. Density has a large effect on how wide a fertiliser can be spread.18 |
Every shipment is a new product.
The same name on the bag doesn’t mean the same spread.
Yara, one of the world’s largest fertiliser manufacturers, says two batches of one product can need different spreader settings.19 One supplier’s UK spec sheet for granular urea lists two source plants with different size bands: 2.0–4.0 mm from Algeria, 2.0–4.5 mm from Egypt.20 Amazone’s chart lists urea plant by plant, and says it can’t guarantee that a product with the same name, from the same manufacturer, spreads like the one it tested.21
Quality can change on the way. In one urea cargo, fines ranged from 7% to 17% between samples from the same grab.22 Ammonium nitrate can swell and break down when it warms and cools around 32°C, especially if damp.23 On a spinning disc, CAN from one plant broke into 3–4% fines; CAN from another broke into 9–15%.24 And in 2023, Rauch said it was seeing many imported ureas with no setting charts at all.25
So treat each shipment as a new product. A trial when it lands tells you how this one spreads, and gives your customers settings that match what’s actually in the bag.
Bringing in regular shipments? Talk to Charlotte about testing each one.
Blends have no “nearest product”.
Blends are the hardest products to set. Each ingredient has its own size and density, so each flies its own distance, and ingredients that differ in size separate as the blend is handled. Blenders aim to match ingredient sizes within about 10%; more than 20% apart counts as incompatible.26 In one heap of CAN and potash, nitrogen ran from 37.5% below target to 21% above, depending on where the sample was taken.27
A blend can look right on the trays and still be wrong. Spreader charts describe how the weight is spread, not the nutrients, and one setting rarely suits every ingredient.28 There’s seldom a similar product in the chart to borrow a setting from, so a farmer setting from the nearest match is guessing.
A trial gives them a setting made for your blend, and shows you where it separates before your customers find out.
11%CV for the blend as a whole
35%CV for the potash in it
Why not just send a sample to the spreader manufacturers?
You should, and many suppliers do. Yara sends products to them regularly, and Thomas Bell does for its imported urea and N+S products.3031 Amazone and Rauch will check a posted sample free; Rauch asks for about 3 kg and quotes one to two days.3233
Each answer is a setting for that sample, on that manufacturer’s spreaders, to be checked in the field. Each manufacturer’s database covers only its own machines; Kuhn / Rauch (Kuhn sells Rauch-built spreaders in the UK, France and Italy) holds settings for about 2,700 fertilisers.34 Your customers run several brands.
| A spreader manufacturer’s sample check | An SCS trial | |
|---|---|---|
| Machines | That manufacturer’s spreaders | The UK’s most popular spreaders, side by side |
| Where | A test hall, or a lab estimate | Full width in the field, trays every metre |
| Samples | One sample | Every bag analysed, and shipment against shipment |
| Blends | How the weight spreads | How it spreads, and where it separates |
| You get | A setting to check in the field | Settings by machine, width and disc, and a verdict on whether it’s fit to sell |
Trials at Rookery Farm.
We run independent spreading trials at our farm in Staffordshire, on the spreaders UK farmers buy most, with the trays and test kit we use on NSTS tests every day. If it goes through a spreader, we can test it.
Before you import
Send us a sample: a bag, or a few. We analyse each bag separately, so you can see whether the product is consistent, then put it through real spreaders to see whether it spreads evenly at the widths UK farmers use. You get a straight answer on whether it’s fit to sell before you commit to a shipment.
When a shipment lands
A trial on arrival checks this shipment against what you expected, and gives you settings for what’s actually in the bags.
Settings for your customers
Settings for the UK’s most popular spreaders at different bout widths and with different discs, in a form you can send out with the product. It gives farmers a sound starting point. They’ll still need their own spreader tested, because no two are set up the same.
New products and blends
Developing a product or a blend? We’ll show you how it spreads across machines, widths and rates, how consistent it is, how much dust it makes and where it separates, so you can put it right before launch.
Pellets, lime and amenity
Organic, digestate and food-waste pellets, granulated lime, amenity fertiliser for turf, golf and sport, and slug pellets, on the machines each one goes through.
Our machines
The main spreading systems used on UK farms, outward- and inward-spinning, with a full range of discs and vanes:
- Amazone ZA-M, ZA-M Ultra, ZA-V and ZA-TS
- Kuhn Axis 30.1 and 50.1 (Rauch)
- Kverneland Exacta HL (Accord Exacta settings comparable)
- KRM M35 (Bogballe Base Trend)
- Teagle Centerliner SX and M36 (DCM)
- Vicon PS 03 and 04
If you need a model we don’t have, we can usually source it, including down-the-spout applicators. We usually need about 300 kg of product per machine to test at two or three widths, and we can run trials all year, weather permitting.
Or ring Charlotte on 01785 840 849.
What we measure.
Every bag gets the same analysis we carry out on a farmer’s fertiliser before an NSTS test. Then it goes through the spreaders.
| What | How we measure it | Why it matters |
|---|---|---|
| Granule size | Sorted through a grader box, bag by bag | Bigger granules fly further, and a wide spread of sizes separates and stripes. Teagasc’s target is 80% of granules between 2 and 4 mm.18 |
| Bulk density | A known volume filled and weighed | Heavier granules carry further. Light products need narrower bouts.18 |
| Crush strength | Granules crushed in a strength tester | Soft granules shatter on the vanes and fall short, and the dust drifts.24 |
| Dust and fines | What passes the finest sieve | Fines fall short and blow about, and show breakage in handling. |
| Consistency | Each bag analysed separately | Shows whether the product, or the shipment, is the same throughout. |
| Spread pattern | Full-width tray test, trays every metre, on each machine, width and disc | The CV, and whether the product reaches the tramline. |
| Rate | Measured at each setting | So the setting puts on the rate the farmer asks for. |
There are standard methods for sieving and bulk density (EN 1235 and EN 1236),35 but no European standard for crush strength, because laboratories couldn’t agree on one, so results only compare on the same equipment.36 We test every bag and every shipment on the same kit, so you’re comparing like with like.
How a trial works.
Product characterisation
Depending on the project: granule or pellet size distribution, bulk density, crush strength, appearance and consistency, fines and dust, and how it flows and handles.
Preliminary application assessment
Which machines suit it, likely working widths, first settings, and any obvious limits or handling problems.
Field spreading trials
Full-width tray tests, trays every metre, measuring how evenly it spreads, at different widths and settings, across machines, and between formulations or prototypes.
Development feedback
During development, what we found and what it points to: size, durability, fines, a different application method or a narrower width.
Commercial validation
Once the product is final: working widths, suitable spreaders, practical settings, repeatability and limits, written up for your technical and customer guidance.
Not every trial needs every stage or every test. We’ll agree what yours needs before we start.
Filming packages
We can film your trial as well: GoPro footage from the spreader and footage of the product spreading across the tray line, for your sales and technical material.
- Product
- Imported AN, 34.5% N
- Samples
- 4 bags, analysed separately
- Granules 2–4 mm
- 86–91%
- Bulk density
- 0.98–1.01 kg/l
- Strength
- Consistent across all bags
- Verdict
- Spreads evenly to 36 m
| Spreader | 24 m | 36 m |
|---|---|---|
| Spreader A, standard discs | 42 / D | 38 / F |
| Spreader B, wide discs | 31 / 4 | 29 / 6 |
| Spreader C | E 3.5 | E 4.5 |
Tray tested, trays every metre
Work we’ve done.
Trials and setting data we’ve produced for fertiliser, lime and pellet suppliers. Where a client has published the work, or the trade press has, we name them; otherwise we describe the work without naming the client.
Nitram at 36 m
We trialled CF Fertilisers’ Nitram at 36 m on five popular spreaders. Every CV was under 10%, from 7.2% to 9.0%.37
Lime setting tables
Multi-brand setting tables for LKAB’s Calcifert lime: a granule analysis, plus settings for Amazone, KRM, Kverneland, Accord, Kuhn and Teagle spreaders at 24, 30 and 36 m.38
Slug pellet data
The data behind Certis’s slug pellet Calibration Wizard: seven common applicators, each tested with all eight Certis pellets for pattern, flow and rate.39
Gypsum and granulated lime
Spreading trials on gypsum and granulated lime products for a building-materials manufacturer.
Granulated digestate
Trials on a granulated digestate, a recovered-nutrient product, for a clean-technology company.
A granulated carbon product
Trials on how a granulated carbon product goes through farm spreaders.
Slug pellet efficacy trials
Spread pattern and working width work alongside an independent trials organisation’s slug pellet efficacy trials.
Imported nitrogen
Origin Fertilisers worked with us in 2021–22 to understand how nitrogen from a wider range of manufacturers behaved.40 Thomas Bell sells its imported PULAN AN quoting our view that, with the correct settings, it spreads as accurately as any prilled AN on the market.41
Who we work with.
- Importers and merchants bringing product in from overseas
- Manufacturers launching or reformulating a product
- Blenders making their own blends
- Organic and pellet producers: digestate, food-waste and manure pellets
- Lime, amenity and slug pellet manufacturers
- Product developers: R&D and technical teams, recycling and circular-economy businesses, mineral and quarry companies, granulation and pelleting businesses, universities and agricultural technology start-ups
We can provide the spreading and application part of a wider development or research programme, alongside manufacturers, universities, research and contract research organisations, granulation specialists, machinery manufacturers and consultants. Our trials are independent and run on commercially representative farm spreaders.
We don’t trial liquid products, formulate chemistry, run agronomic efficacy or regulatory approval trials, or do laboratory fertiliser chemistry. We work alongside the people who do.
We wrote the original qualification for fertiliser spreader testing that NSTS adopted, and we’ve worked with spreader, fertiliser and pesticide manufacturers for more than 35 years.
We have used SCS for many years and recommend them for consistently providing a reliable and efficient service to us and our customers.
Questions.
Is there a legal requirement to test how a fertiliser spreads?
No. UK fertiliser law sets limits on nutrient content, and high-nitrogen ammonium nitrate must pass a detonation test, but nothing requires a fertiliser to be tested for how it spreads before it’s sold. That’s why a trial is the only way to know.
Don’t the spreader manufacturers test fertiliser for free?
Some will check a posted sample and suggest a setting for their own machines, and it’s worth doing. A trial with us puts your product through the UK’s most popular spreaders side by side, full width in the field, with every bag analysed, so you get settings for the machines your customers actually run.
Why trial a fertiliser that’s already in the spreader manufacturers’ charts?
Charts come from test halls, from a sample of the product as it was when it was tested. Your shipment may come from a different factory, or have been knocked about or got damp on the way, and two batches of one product can need different settings. A trial tells you how the product you’re actually selling spreads.
Do farmers still need their own spreader tested?
Yes. A trial gives farmers a sound starting point for your product, but every spreader is set up differently, with its own wear, tractor and headland settings. An NSTS test sets their machine up for your fertiliser.
Can you trial a blend?
Yes. Blends are where trials help most, because there’s rarely a similar product to borrow a setting from. We look at how each bag compares, where the blend separates, and how it spreads on each machine.
How much sample do you need, and how long does it take?
It depends on the trial: how many machines, widths and discs you need settings for. Tell us what you need and we’ll tell you how much to send and when you’ll have results.
Which spreaders do you use?
A fleet of the spreaders sold most in the UK, with their common disc sets. We agree the machines, widths and discs with you before we start.
Do you trial products other than fertiliser?
Yes: organic, digestate and food-waste pellets, granulated lime, amenity fertiliser for turf and sport, and slug pellets. If it goes through a spreader, we can test it.
Developing a product? Talk to us early.
Speak to us before the physical specification or the application guidance is fixed. Tell Charlotte about the product, the equipment it’s meant for and the working width you’re aiming at, and she’ll come back to you with how a trial could be structured.
- What the product is, and how far along it is: prototype, pre-commercial or on sale
- How it will be applied, and the working width you’re aiming at, if you know
- Roughly how much product you can send
- The main question you want the trial to answer
Sources
- CF Industries, Annual report (Form 10-K), financial year 2025, 2026.
- Defra, British Survey of Fertiliser Practice, crop year 2025, statistics notice, 2026.
- HMRC, UK overseas trade statistics, fertilisers (chapter 31), our extraction, 2025.
- AHDB, GB fertiliser prices, week to 2 October 2026.
- Defra, UK fertilisers: regulatory reform, consultation, March 2026.
- legislation.gov.uk, Regulation (EC) 2003/2003 on fertilisers, as retained, Article 13 (tolerances), 2003.
- GOV.UK, Manufacturing and marketing fertilisers, accessed 2026.
- Farmers Weekly, Importers on alert to meet SP ratings, 1997.
- Irish Farmers Journal, Quality of protected urea key to even spreading: Teagasc, 2025.
- Agricultural Industries Confederation, FIAS: Fertiliser Industry Assurance Scheme, 2026.
- Yara UK, Spreader calibration, accessed 2026.
- Kverneland, Kverneland spreading charts, accessed 2026.
- Teagasc (Dermot Forristal), Accurate spreading: six steps you need to take, Today’s Farm, 2023.
- profi, Spreading granular fertiliser wider, 2024.
- Irish Farmers Journal, Where to now for protected urea?, 2024.
- Farmers Weekly, Fertiliser spreader test: Amazone ZA-M, 2011.
- Yara UK, YaraVera AMIDAS against a urea and sulphur blend: tray test results, 2025.
- Teagasc, Fertiliser spreader tray test and field procedure, leaflet 16, 2025.
- Yara UK, Spreading preparation, accessed 2026.
- OCI Nitrogen, Product specification: Granular Urea 46 (UK), 2023.
- Amazone, ZA-M fertiliser setting chart, accessed 2026.
- The Swedish Club, Urea: caking of urea at the discharge port, 2023.
- Fertilizers Europe, Guidance for the storage, handling and transportation of solid mineral fertilizers, 2015.
- J. W. Hofstee, Wageningen University, Physical properties of fertilizer in relation to handling and spreading (PhD thesis), 1993.
- LfULG Sachsen / SKW, Workshop slides reproducing a 2023 Rauch notice on imported urea, 2023.
- Canadian Fertilizer Institute, Bulk blending manual, 2013.
- Moitzi et al., BOKU and Borealis, Segregation of solid fertilizer blends, 2015.
- Amazone UK, EasyMix press release, 2019.
- Holmes et al., Massey University FLRC, Nutrient distribution from blended fertiliser in the field, 2024.
- Yara UK, Spreader settings, accessed 2026.
- Thomas Bell, Spreader settings, accessed 2026.
- Rauch, Fertiliser sample form, March 2026.
- Amazone, FertiliserService, accessed 2026.
- Kuhn UK, Best tests, more precision, accessed 2026.
- BSI, EN 1235 / ISO 8397: solid fertilisers, test sieving, accessed 2026.
- IFA (Samec), Determination of granule crushing strength: interlaboratory work behind CEN/TR 12333, 1996.
- CPM, Fertiliser feature: Nitram at 36 m (supported by CF Fertilisers), September 2021.
- LKAB Minerals, Calcifert lime spreader settings, 2023.
- Agriland, New online tool aids more accurate slug pellet application, 2020.
- Farm Contractor, Spreader calibration is more important than ever (Origin Fertilisers and SCS), 2021.
- Thomas Bell, PULAN ammonium nitrate, accessed 2026.