Which trials can I do, and how do I set them up?

Field trials investigate the product under farming conditions. They help show how it performs amid differences in weather, soil and crop growth.

The design needs to account for that variation so the result does not simply reflect a better part of the field.

A trial programme is a way of organising several studies, not a separate growing environment. Suitability for assessment depends on the claim and chosen approach.

The precise layout, number of repeats and dimensions depend on the crop, claim and applicable provisions.

Strip trials compare larger areas under farming conditions. They can be practical for commercial farms, but differences across the field can make results harder to interpret.

Ask how they fit into the wider evidence programme before relying on them for assessment.

Growth rooms, climate chambers and other controlled environments allow researchers to study an effect more closely.

They can help answer a focused question, but a result in controlled conditions does not automatically show performance on a farm. Agree whether this approach is suitable for your claim.

Trials across different places or seasons can give a broader picture. Combining results needs careful planning; separate studies cannot always be treated as one programme.

The comparison should make it possible to identify the product’s effect. The use tested should fit the intended label, and the measurements should answer the claim.

A qualified trial specialist should plan how to handle natural variation and analyse the results. The detailed design belongs in the trial plan, not in this overview.

Keep the records behind the report and explain important changes or problems. The assessor needs to understand what was tested and how the conclusions were reached.

For example, a wheat trial might compare the product with a treatment that does not receive it, while keeping the variety and normal crop management comparable. If the product supplies nutrients, the comparison also needs to address that difference.

Putting all treated plots at the fertile end of a field would make the result difficult to interpret. Random allocation helps avoid favouring a treatment. Blocks can help organise comparisons across a soil gradient.

These are general experimental design ideas, not a complete protocol. The specialist must choose a layout appropriate to the site and claim.

Repeated treatment plots give a picture of natural variation. Without that picture, a small difference between treatments can look more convincing than it is.

The area measured must also be suitable for the crop and practical operations. Edge effects, uneven application and the way the crop is harvested can all influence results. Bigger plots do not automatically make a weak design reliable.

The official standards contain precise design provisions. Ask the provider to explain how its proposed design meets the chosen approach rather than copying a generic layout.

These selected figures help you understand a provider’s proposal. They summarise EN 17700-1:2024 in original wording; they are not a complete design.

For example, two treatments with four repeated plots each give eight plots, but still only one trial. The total trial programme must separately cover the intended claim and crops.

Controlled-condition trials are not part of the field-trial-series route. Also distinguish a greenhouse used under normal crop-growing practice from an experiment that deliberately controls the environment.

Decide which result will answer the claim, and when it will be measured. For a quality question, harvest weight alone may miss the trait you wanted to show.

Plan the analysis before seeing the results. Record the size of the effect and the variation, not only whether a statistical test passes. A statistically convincing result can still have little practical value, and a promising difference may remain too uncertain.

EN 17700-1:2024 sets a significance threshold of p < 0.15 for individual field or protected-crop trials and for field-trial-series analysis. For individual trials under controlled conditions, it uses p < 0.10.

These correspond to the standard’s stated minimum confidence levels of 85% and 90%. They are not an 85% or 90% probability that the product works. A p-value concerns how compatible the observed result is with the statistical no-effect model, given the assumptions.

Ask the specialist to explain both the effect size and the uncertainty. Passing a threshold does not replace a fair design, meaningful measurements or a useful agronomic effect.

The plan should link the product, intended use and claim to the comparison and measurements. During the trial, keep enough information to explain the conditions and any departures from the plan.

The report should make it possible to follow the evidence from the original measurements to the conclusion. Photos add context, but do not replace comparable measurements.

• Comparing fields with different management as if the product were the only difference.
• Changing the main measurement after seeing which result looks best.
• Drawing a farm-performance conclusion from a small exploratory pot test.
• Keeping a graph but losing the data behind it.

The company doing the trials should be able to show that its staff are competent and that the work follows suitable quality criteria. Check this before commissioning the work.

Certification is not a blanket requirement for every biostimulant efficacy trial. Ask your notified body whether it requires a particular certification, accreditation or recognised quality scheme for your assessment. A certificate alone does not guarantee acceptance.

The EN 17700 series provides a recognised framework for evidence supporting plant biostimulant claims. Using standards is voluntary; the product must still meet the legal requirements.

This article combines original explanations with selected numerical and scope requirements from the standards. It is not a complete protocol or a substitute for the official standards and their full conditions. Agree the chosen approach with a qualified trial specialist and your notified body.