With large numbers of relatively untested bio-stimulants and other products now available, a growing number of farmers are interested in conducting on-farm trials where they evaluate products, techniques, or systems in their own fields.

At the Teagasc National Tillage Conference, Dermot Forristal and Jack Jameson hosted a workshop on why and how farmers can conduct these field evaluations.

They said that these trials can help farmers to evaluate and validate products and systems in their own specific location and farm system.

If a farmer gets an interesting result, they can also let Teagasc know in case it warrants further investigation.

Here, we go through how you can perform a trial on your farm.

Choosing a field

Ensure that there is a uniform soil type, the field has not been split into different crops in the past, soil tests are available, and the field is large enough to have a number of tramlines.

A trial should not be conducted on headlands, well-trafficked or awkward-shaped areas, or in wet spots and shaded areas. Poles or other obstructions also make it very difficult to perform accurate and fair trials.

Replicating a treatment

To ensure a fair trial, you must test each product or treatment more than once, in more than one area. This helps to account for variations in a field.

Testing the product three or four times would be ideal and gives you more confidence in your result.

For a tramline trial, one tramline can be a plot. However, if the tested product is applied via fertiliser spreader, this will not work due to the spread patterns crossing tramlines.

Reproducing the trial in a number of fields is even better. You could ask neighbours, friends or discussion group members to conduct the same trial in their fields and share the results.

Always ensure you have a control treatment, which will be where the product is not applied, or standard practice is implemented.

Do not change your plans by adding or changing treatments during the season.

Record what is being applied to each tramline and place a plastic post in the field to remind yourself when spraying.

Depending on what you are testing, you may want to collect different types of data.

However, grain yield and moisture content will always be critical. A combine-mounted yield monitor is very helpful in this regard. If one is not available, there are other options.

If you have a weigh bridge, you could cut each tramline width, which you included in the trial, separately if time allowed, or you could take head counts before harvest, cut some heads and weigh the grains to work out an approximate yield. Hectolitre weight may also be important. All management actions should be recorded.

Diseases should be identified and their abundance recorded, for example the percentage of septoria on the flag leaf or leaf 2 of winter wheat. Satellite data such as NDVI may show differences in some cases when crops are still green. There are some computer programmes which you can download these maps from.

After harvest, you need to examine your data. In official trials, this is done through statistical analysis. You can have more confidence in your result if there is a high weight of evidence, ie the trial is repeated in a number of replicates or tramlines in this case, a number of trial sites or fields, and if the trial is conducted over a number of years. This takes time and effort, and all work must be done to a high standard and in the same way to get an accurate result. While these trials will not replace official trials, they can provide useful guidance to farmers. As a final piece of advice, Forristal and Jameson advised farmers to plan carefully, keep it simple, and to talk to their Teagasc adviser before planning a trial.

1 Whole-field trial

While trying a new product or system on a whole field is easy to do, you cannot compare the results to anything else, and you will not know if the new treatment is providing a benefit.

2 Split-field trial

Treating half a field provides a bit more insight but any difference in the two sides of the field could still be due to soil type, compaction, topography, or other factors.

3 Tramline trial

A tramline trial allows proper examination of the benefits of a treatment. It may take more time and requires careful planning.