01785 840 849Call SCS on 01785 840 849 Book a test

Do spreaders with radar or automatic settings still need tray testing?

Weigh cells, radar on the discs, spreaders that adjust themselves. They’re clever, and they help. Here’s what they measure, what they can’t, and what the manufacturers themselves say about checking them.

By Spreadcheck, NSTS testers. Published . 5 minute read.

The short answer

Yes. Automatic systems adjust the spreader from what they measure at the disc, starting from the manufacturer’s test-hall data, but none of them sees where every granule lands in your field. Amazone’s own manual says a test kit is mandatory with its ArgusTwin radar system.

  • Amazone’s ZA-TS manual: “With ArgusTwin, use of the mobile test rig or EasyCheck is mandatory!”1
  • Even Amazone’s new self-adjusting ZA-TS 01 AutoSpread, due on general sale in 2027, prompts a check with EasyCheck mats when the pattern doesn’t match what it expects.2
  • Weigh cells set the rate, not the spread: Teagasc notes that even spreading isn’t necessarily helped by electronic control or GPS.3
  • Radar systems measure fertiliser as it leaves the disc.45 Wind, slope and the crop act on it after that.
  • Each manufacturer’s data covers its own machines; an independent tray test works the same on every make.

What the automatic systems actually do

  • Weigh cells weigh the hopper as you go and adjust the shutters, so the rate stays right as the fertiliser’s flow changes. They control how much comes out, not where it goes.6
  • Radar on the discs. Rauch’s AXMAT uses two rings of radar sensors, 54 in all, to watch the fertiliser leaving each disc, and moves the point where fertiliser drops onto the disc to correct the pattern.4 Amazone says its ArgusTwin radar adjusts automatically for things like variable fertiliser quality, coating on the discs, worn vanes and slopes.5
  • Self-adjusting spreaders. Amazone’s ZA-TS 01 AutoSpread, due on general sale in 2027, measures how the fertiliser flies and compares it, through an online connection, with the pattern its test hall recorded for that fertiliser, then adjusts the spreader to match.2 Amazone hasn’t published exactly how it measures the flight, and trade reports describe the sensors differently.

All of this is a real step forward, and it catches problems that used to go unnoticed until the crop striped.

What they can’t see

Every one of these systems works from two things: a measurement taken at or just behind the spreader, and a reference pattern for that fertiliser from the manufacturer’s test hall. Neither is the field.

  • What happens after the disc. Once a granule leaves the vane, wind, slope, bumpy tramlines and crop height decide where it lands. In New Zealand tray tests, a 6 m/s cross wind cut the usable bout width for DAP from 21 m to 13 m.7 No sensor on the spreader measures the ground.
  • The reference. The system compares what it sees with a pattern recorded in a test hall for a fertiliser it has matched to yours. Two batches of the same product can need different settings,8 and test halls achieve under 5% CV where up to 15% is acceptable in the field.9
  • The fertiliser changes as the hopper empties. Granules sort themselves by size whenever fertiliser is poured into or out of a bag, heap or hopper,10 and blends separate as they flow through the hopper and metering, as well as in the air.11 The reference pattern comes from a well-mixed sample in a hall; the last few hundred kilos in a hopper that’s been bouncing across a field are a different mix.
  • The rate is not the pattern. Teagasc notes that even spreading isn’t necessarily helped by electronic control or GPS.3

What the manufacturers say

The clearest answer comes from the manufacturers themselves. Amazone’s ZA-TS manual is blunt: “With ArgusTwin, use of the mobile test rig or EasyCheck is mandatory!” The test rig is 16 trays; EasyCheck is 16 rubber mats read by a phone app.1 And Amazone says its self-adjusting AutoSpread will prompt a check with the EasyCheck mats whenever anomalies occur or the measured pattern doesn’t match its reference.2

In other words, the most advanced spreaders on the market still rely on fertiliser caught on the ground to know they’re right. They make the check quicker and tell you when it’s needed. They don’t make it unnecessary.

If you’re buying a spreader

Spec-sheet widths and CVs come from test halls, with a known sample of fertiliser, indoors.129 They’re a fair way to compare machines from the same maker, but they don’t tell you how a spreader will do with your fertiliser, at your width, on your fields. Each manufacturer’s data also covers only its own machines.

The way to compare is the same for every make: put your fertiliser through it, at your bout width, over trays, and look at where it lands. We test every make of spreader, so a test report from us means the same thing whichever badge is on the hopper.

A sensible routine for an automatic spreader

  1. At first use and each season: a full tray test with your main fertilisers, so the system starts from a pattern that’s right on your farm.
  2. New product or batch: let the system match the fertiliser, then check it with a few trays or mats. The AIC advises a tray test for each new type, brand or batch.13
  3. When the system flags something: do the check it asks for. That’s what it’s for.
  4. After new vanes, discs or other parts: test again. The AIC advises a fresh tray test after servicing or new parts.13

Other questions people ask

Does a spreader with weigh cells need a tray test?

Yes. Weigh cells measure how much fertiliser leaves the hopper, so they keep the rate right. They can’t tell where it lands across the bout. Teagasc notes that even spreading isn’t necessarily helped by electronic control or GPS.3 See how to calibrate a spreader.

Can an app work out my spread pattern without trays?

Not without fertiliser on the ground to look at. Apps such as Amazone’s EasyCheck and Rauch’s XCheck analyse a photo of the mats or trays you’ve spread over,1415 so they’re a quicker way of reading a tray test, not a replacement for one.

Will a self-adjusting spreader replace testing?

Amazone says its ZA-TS 01 AutoSpread compares what it measures with test-hall data for the fertiliser, and prompts a check with EasyCheck mats when something doesn’t match.2 So even the newest systems still fall back on fertiliser caught on the ground.

Do I still need an NSTS test if my spreader is automatic?

The rules don’t change with the technology. Red Tractor asks for yearly calibration with a record, and a spreader used for slug pellets needs an NSTS test under the SUD rules, whatever its controls.1617 See how often should a spreader be tested?

About this article

Written by Spreadcheck (Spreader & Sprayer Testing Ltd), an NSTS testing company at Rookery Farm, Wheaton Aston, Staffordshire, which wrote the original qualification for fertiliser spreader and slug pelleter testing that NSTS adopted. We sell testing, so every figure here links to its source, and we say where the evidence is mixed.

Checked on 12 October 2026. Rules, prices and guidance change, so follow the links for the latest.

Sources

  1. Amazone, ZA-TS quick start manual: orientation aid for the start of the season, section 7, mobile test rig and EasyCheck, 2018.
  2. Amazone, ZA-TS 01 AutoSpread (Agritechnica 2025 innovation), 2025.
  3. Teagasc (Dermot Forristal), Accurate spreading: six steps you need to take, Today’s Farm, 2023.
  4. MSO Messtechnik und Ortung (radar supplier for Rauch AXMAT), Axmat radar sensor, accessed 2026.
  5. Amazone, ArgusTwin: automatic adjustment of lateral distribution, accessed 2026.
  6. Kverneland UK, Exacta TL weighing spreader, accessed 2026.
  7. Grafton et al., Massey University FLRC, Occasional Report 29 (NZ Spreadmark field trials in slope and wind), 2016.
  8. Yara UK, Spreading preparation, accessed 2026.
  9. Teagasc and the Fertilizer Association of Ireland, Precise Application of Fertiliser, Technical Bulletin 3, 2017.
  10. Miserque and Pirard, Chemometrics and Intelligent Laboratory Systems 74, Segregation of the bulk blend fertilizers, 2004.
  11. J. W. Hofstee, Wageningen University, Physical properties of fertilizer in relation to handling and spreading (PhD thesis), 1993.
  12. Kverneland, Kverneland spreading charts, accessed 2026.
  13. Agricultural Industries Confederation, Fertiliser Spreaders: choosing, maintaining and using, 2005, linked from RB209 2026.
  14. Lectura Press, EasyCheck: digital mobile test kit, accessed 2026.
  15. Rauch, XCheck app press release, 2025.
  16. Red Tractor, Combinable Crops and Sugar Beet Standards, version 5.1, EC.7 and EC.10, February 2025.
  17. legislation.gov.uk, The Plant Protection Products (Sustainable Use) Regulations 2012 (the UK’s “SUD” rules), regulation 12, 2012.