Your machine gets an MOT
Every working part is checked before a granule goes in, including the tractor’s PTO speed against what the cab says.
The bag says what’s in it. Our trays show where it lands.
NSTS testing for fertiliser spreaders, sprayers, slug pelleters and granular applicators. No two fertilisers spread alike, so we set your spreader for the one in your shed: trays every metre, full width, anywhere in the UK.
Trays every metre, right across the spread.
Not a sample. A full-width test catches what lands at every metre of the pattern.
Drive through and catch what lands.
Each tray empties into its own tube. Side by side, the tubes draw your spread pattern.
On the chart setting, this batch stripes.
Batch B is lighter than the chart expects. Three passes later, the field shows it.
So we set it for your fertiliser.
We analyse the batch, move the drop point and run it again until the pattern is even.
Your turn.
Narrower
Chart
Tested
Wider
Drag the dial, or grab the discs, and watch the tubes.
Moves where the fertiliser drops onto the discs, which changes how far it is thrown. You can also drag the discs left or right.
Batch B at drop point 5.0, the chart setting. Measuring…
Simulated test, illustrative figures
New spreader, fresh delivery. Do you still need a tray test?
Yes. A spreader’s setting chart is right for the fertiliser it was made with. But fertiliser is a commodity, made all year round in different plants and batches, so the bags in your shed may not be the fertiliser the chart was drawn up for.
Fertiliser’s chemistry is controlled. Its physical make-up isn’t: granule size, density and hardness change from product to product and batch to batch, and they decide how far each granule is thrown. In one independent test-hall trial, a spreader set from its chart gave a 13.6% CV. A tray test brought it to 5.1%. The likely reason: the chart had been drawn up with a coarser fertiliser than the batch in the hopper.
A test doesn’t assume your spreader is wrong. It proves it’s right, with your fertiliser, on your tractor, before you put down the biggest variable cost on the farm.
What the guidance says
Calibrate for rate every spring and whenever you change fertiliser type, and check the spread pattern with trays every year.
AHDB, Nutrient Management Guide (RB209) Section 1, 2026Tray test every time you use a different type, brand or batch of fertiliser. Manufacturers’ setting tables “give guidance only”.
Agricultural Industries Confederation, Fertiliser Spreaders: choosing, maintaining and usingTwo batches of the same product can need different spreader settings.
Yara UK, spreading preparationFertilisers sold under the same name can behave differently, depending on where they were made, how they were moved and stored, and the humidity.
Kverneland, spreading chartsCalibrate the spreader separately for every type of fertiliser. The setting charts are a guide: always do a tray test.
Thomas Bell, fertiliser spreader settingsSettings are for guidance only. Recalibrate the spreader for rate and spread pattern using a tray test.
Origin Fertilisers, spreader settings for AN 34.5%Get every spreader tray tested before spreading starts in spring. A well set up spreader should give a CV of around 10%.
Tried & Tested, National Spreader Testing SchemeOnly 6% of farms with a spreader check the spread pattern every time they change fertiliser. 14% never check it.
Defra, British Survey of Fertiliser Practice, crop year 2025
Same product. Same settings. A different load.
Fertiliser changes from one delivery to the next. Larger, heavier granules fly further. Smaller or softer ones fall short, or break up on the discs.
The chart in the spreader’s manual can’t know which load you’ve got. So before we touch the spreader, we test the fertiliser you’re actually going to spread.
| Measure | How we test it | What it changes |
|---|---|---|
| Granule size | Sorted through a grader box | How far each granule flies |
| Bulk density | A tube of known volume, filled and weighed | How it flows and how hard it’s thrown |
| Crush strength | A random sample crushed in a strength tester | Whether it shatters on the vanes and drops short |
Switch to a denser batch in the test above and watch the pattern change.
Fertiliser is the biggest variable cost of growing wheat.
Spread it unevenly and it costs you twice.
- Too little
- Those strips lose yield, and the over-fed strips don’t win it back.
- Too much
- More lodging and disease, missed malting and milling specifications, and nitrate left to leach.
| The figure | What it means |
|---|---|
| £35,500 | What the average English cereal farm spent on fertiliser in 2024/25. Defra, Farm Business Survey, Farm Accounts in England 2024/25 |
| About £400/ha | Fertiliser for a hectare of winter wheat, more than half its variable costs. AHDB, harvest 2027 crop budgets, June 2026 |
| 0.27 t/ha | Cereal yield lost where a strip gets 40 kg N/ha less than it needs. At 100 kg short, it’s over a tonne. AHDB, Nutrient Management Guide (RB209) Section 4, 2026 |
| Up to 75% | Yield lost when cereals lodge around ear emergence. Too much nitrogen raises the risk. AHDB, An introduction to lodging in cereals |
| 1.60–1.75% N | The grain nitrogen band for UK brewing barley. About 30 kg N/ha moves grain N by 0.1 point, and loads outside specification face deductions or rejection. Maltsters’ Association of Great Britain, barley requirements AHDB, Nutrient Management Guide (RB209) Section 4, 2026 |
| About £20/ha | Margin lost in wheat and oilseed rape at a 25% CV, often found before a test, against the 5% a test can achieve. Farm Advisory Service (Scotland), Fertilisers and spreader calibration, 2018 |
What is a test worth to your farm?
Our free calculator works out what uneven spreading could be costing you each year, and what a test could save. Put in your crops, your spreaders and your fertilisers; there’s nothing to sign up for, and it shows every step of the sum.
- 1Your crops and hectares
- 2Your spreaders
- 3Your fertilisers
- 4How even it spreads now
A typical arable farm130 HA
- Winter wheat
- 74 ha
- Winter barley
- 15 ha
- Spring barley
- 18 ha
- Oilseed rape
- 14 ha
- Oats
- 9 ha
- Uneven spreading costs
- £1,898 a year
- A test is worth
- £1,588 a year
A 25% CV before the test and 10% after, with Defra, AHDB and RB209 figures. Lodging, grain quality and headlands not counted.
Put in your own farmWhat happens on the day
An SCS engineer comes to you with the trays, the kit and an iPad to record everything. Here’s what they do.
Your fertiliser gets analysed
Bulk density, crush strength and granule size, from the bags you’ll be spreading. It’s how we catch a batch that won’t behave.
The full-width tray test
Trays every metre across the whole spread. We drive through, collect what lands, work out the CV, adjust the spreader and go again until the pattern is right.
You get the NSTS report
Settings, photos and the conditions on the day, emailed to you and uploaded to the NSTS database. If the first run was off, the report estimates what it was costing you.
Spreader test reportEXAMPLE
- Product
- AN 34.5% N, batch B
- Bout
- 24 m, trays every 1 m
- First run
- CV 24.3%
- After adjustment
- CV 3.1%
- Evidence
- Photos, settings, conditions on the day
Uploaded to the NSTS database
Every NSTS test carries the NSTS certification fee. It’s what keeps the assurance inspector happy.
We wrote the test.
SCS wrote the original qualification for fertiliser spreader and slug pelleter testing. NSTS adopted it.
We’re the Foxalls, fifth-generation Staffordshire farmers, and Rookery Farm in Wheaton Aston is our head office. For more than 35 years we’ve worked with the people who make spreaders, fertiliser and pesticides, and our test methods and equipment come out of that work.
We’re a farmer-led team, and our engineers are among the most knowledgeable and up to date in the industry.
What we test
| Machine | Machine | What the test covers | How often |
|---|---|---|---|
| Fertiliser spreaders | MOT-style check, fertiliser analysis and a full-width tray test. Farm-scale twin-disc spreaders and broadcasters, down to the small spreaders used on orchards and greens. | Every year, for farm assuranceA yearly calibration with records for Red Tractor, SQC and QMS. | |
| Sprayers | Every application component, with the operator’s and the environment’s safety in mind. Knapsacks, weed wipers and Amistar applicators, up to the widest self-propelled sprayers. | Every year to every six yearsBooms over 3 m: every year for Red Tractor Crops and SQC. Smaller sprayers: every six years. | |
| Slug pelleters | Machine check, pellet analysis and a spread test, whether you apply pellets with a pelleter, a fertiliser spreader or a spout. | By its fifth birthday, then every six yearsRequired by law and by farm assurance. | |
| Granular applicators | Every application component, then a static output test or a patternation tray test. All types, pneumatic and placement, for any product: most often Nemathorin and Avadex. | Every year to every six yearsNematicide applicators every year for Red Tractor and SQC; Avadex every six years. |
Nationwide coverage. Every NSTS test carries the NSTS certification fee. Farm tests in full: what each test covers, how often each machine is due, and what you get.
Book a testGolf courses, sports pitches, racecourses and turf
We test the pedestrian and small spreaders that grounds teams use: on golf courses, at football and rugby clubs, racecourses and schools, and for turf growers. It fits in alongside the maintenance you already do on your machines.
On turf, the first question is usually the rate. If 25 bags should do that pitch, does it, or do you run short before the last corner? So we check how much comes out as well as where it lands, on smaller trays that suit narrower widths.
More than the annual test
Spreading trials and product development
Independent spreading trials for fertiliser, pellet and lime manufacturers, importers and product developers, from prototype to machine settings, run in real field conditions on the spreaders your customers use. If it goes through a spreader, we can test it.
- Agricultural fertiliser and lime
- Pelleted fertiliser, including organic and bio-based products, digestate and food-waste pellets
- Biochar, carbon and recovered-nutrient granules
- Amenity fertiliser and seed for turf, golf and sport
- Slug pellets
Talk to Charlotte about a trial Trials and product developmentWe have used SCS for many years and recommend them for consistently providing a reliable and efficient service to us and our customers.
Fertilisers & Spreaders course
Half a day at Rookery Farm for agronomists, advisers and anyone who sells fertiliser or spreaders. Classroom theory, then tray testing in the field and more than ten spreaders in the workshop.
- Length
- Half a day
- Group
- 5 to 20 people
- Where
- Rookery Farm, Staffordshire
- CPD
- 10 BASIS/FACTS points, subject to BASIS approval
All Hutchinsons new entrant agronomists attend the course prior to FACTS training.
We also run operator courses on your farm for assurance and supermarket schemes.
Ask about course datesCheck it yourself between tests
Batches change through the season. A kit lets you check the pattern when a new load arrives, or get going before a full test.
Ask about kits| Kit | For | Price |
|---|---|---|
| 7 trays | Spot checks through the season | Contact us for a quote |
| 50 trays | Full width up to 30 m, with the fertiliser analysis kit and everything you need to set out the trays | Contact us for a quote |
| 60 trays | Full width up to 36 m, with the fertiliser analysis kit and everything you need to set out the trays | Contact us for a quote |
Also available: fertiliser analysis kits, grader boxes, strength testers, tubes and holders, anemometers, RPM meters, and water- and oil-sensitive paper for sprayers.
Questions farmers ask us
Straight answers, with the sources, so you can check them.
The full guide to spreader testingI’ve got a new spreader. Do I still need a tray test?
Yes. A new spreader’s chart settings come from a test hall, using a fertiliser sample that may not match yours, set up on a tractor that isn’t yours. Mounting height, levelling, PTO speed, headland settings and the batch in the hopper all change the pattern. Yara, which makes fertiliser, says even a brand-new spreader needs calibrating. A test proves the settings are right for you.
Sources: Farmers Weekly, Yara advice on calibrating spreaders, 2008 Agricultural Industries Confederation, Fertiliser Spreaders: choosing, maintaining and using
Isn’t the manufacturer’s setting chart or app good enough?
It’s the right place to start, not to finish. Setting charts are made under controlled test-hall conditions with a particular product. The Agricultural Industries Confederation says manufacturers’ tables give guidance only, and Teagasc calls them approximate guides. In one independent hall test, a spreader on its chart settings gave a 13.6% CV and a tray test brought it to 5.1%, because the chart was based on a coarser fertiliser than the batch being spread.
Sources: Agricultural Industries Confederation, Fertiliser Spreaders: choosing, maintaining and using Teagasc and Fertilizer Association of Ireland, Precise Application of Fertiliser, 2017 Farmers Weekly, independent spreader test at Bygholm, 2011
Does the same fertiliser always spread the same way?
No. A fertiliser’s chemistry is controlled, but its granule size, density and hardness are not, and they decide how far it is thrown. Yara says two batches of the same product can need different spreader settings. Kverneland says fertilisers sold under the same name can behave differently depending on where they were made, how they were transported and stored, and humidity. Damp storage can soften granules and cause caking. That’s why every SCS test starts by analysing the fertiliser you are going to spread.
Sources: Teagasc, Accurate spreading: six steps, 2023 Yara UK, spreading preparation Kverneland, spreading charts Yara, physical properties of fertilizers
How often should a fertiliser spreader be tested?
AHDB’s Nutrient Management Guide (RB209) says to calibrate for rate every spring and whenever you change fertiliser type, and to check the spread pattern with trays every year. The Agricultural Industries Confederation advises a tray test every time you use a different type, brand or batch. Red Tractor requires fertiliser application equipment to be calibrated at least annually. We recommend testing with each fertiliser you plan to use this season.
Sources: AHDB, Nutrient Management Guide (RB209) Section 1, 2026 Agricultural Industries Confederation, Fertiliser Spreaders: choosing, maintaining and using Red Tractor, Crops and Sugar Beet standards
Is a spreader test a legal requirement?
For a spreader used only for fertiliser, no UK law requires a test. The rules for nitrate vulnerable zones do require nitrogen to be spread as accurately as possible and keep manufactured fertiliser at least 2 m from surface water. Slug pellet applicators are different: by law they need an NSTS test before they are five years old and every six years after that, and Red Tractor and SQC apply the same to fertiliser spreaders used to apply slug pellets.
Sources: gov.uk, Using nitrogen fertilisers in nitrate vulnerable zones Plant Protection Products (Sustainable Use) Regulations 2012, regulation 12 NSTS, slug pellet applicator test
What CV should my spreader achieve?
Under 10% is good. AHDB’s RB209 says a coefficient of variation above 15% means significant inaccuracy and the spreader needs attention. The National Spreader Testing Scheme says stripes become visible above about 20%, but a crop with no stripes is no guarantee of an even spread: yield is lost before you can see it.
Sources: AHDB, Nutrient Management Guide (RB209) Section 1, 2026 Farm Contractor, AEA launches the National Spreader Testing Scheme, 2015
What does uneven spreading cost?
The Farm Advisory Service in Scotland puts a 25% CV, which it says is often found before testing, at about £20 a hectare of lost margin in wheat and oilseed rape compared with a tested 5%. AHDB’s RB209 shows a strip 40 kg N/ha short of its optimum losing about 0.27 t/ha of cereal. Over-fed strips don’t win that back: they are more likely to lodge, carry disease and miss malting or milling specifications. FAS found a professional test pays for itself in about 12 hectares.
Sources: Farm Advisory Service (Scotland), Fertilisers and spreader calibration, 2018 AHDB, Nutrient Management Guide (RB209) Section 4, 2026 AHDB, An introduction to lodging in cereals
What happens on an SCS spreader test?
An engineer comes to your farm and carries out an MOT-style check of the machine, including the tractor’s PTO speed; analyses your fertiliser for bulk density, crush strength and granule size; runs a full-width tray test with trays every metre, adjusting the spreader until the pattern is right; and issues an NSTS report with the settings, photos and conditions on the day, emailed to you and uploaded to the NSTS database.
Most spreading starts in January. Get your tray test done before you start.
Most of our tests happen between January and May, but we test all year round. Book ahead and your test is done before your next pass.
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
Our busiest monthsThis month
Or ring the office
01785 840 849- info@spreadcheck.com
- Head office
- Rookery Farm
Wheaton Aston
Staffordshire ST19 9QF