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Tillage Update - 27th January 2022

How did your on farm trials work out last year? If you did not do any, what plans do you have this year to check whether the products you are applying are value for money?. Michael Hennessy, Head of Crop KT, Teagasc suggests carrying out replicated trials on your farm. He explains the process here

On farm trials - are you doing enough of them? 

It's no different to occasionally checking your miles per gallon in your car/jeep (or litres per 100 km in new money!). Every year should be treated as an opportunity to test something new on your farm.

The cornerstone of agricultural development has been to trying different practices on farm to see if there was an improvement.  This have developed through research centres to encompass replicated trials so that the differences could be statistically analysed.   

Replicated trials

These replicated trials, which should be peer reviewed, are the gold standard as regards what farmers can expect from a new technology or a new practice.   However, these trials take a lot of setup and time to develop in terms of thinking through how to measure one component so that adjusting that particular compound within the management of the crop can be measured. It's certainly tempting to compare different treatments with more than one adjustable factor, such as comparing conventional plough-based system to the newer no-till systems. But each of these systems are practiced differently, thereby making it difficult to pinpoint which change had the greatest (or any) influence on the final yield.

When we want to compare a new variety or a new plant protection product replicated trials are still the best place to find an answer.  It's often tempting for people who conduct these trials to present the figures in a way that is most beneficial to their product. However when you know what to look for it can be easy to distil whether the information is presented in the most flattering light or is there some more information missing which would contextualise the results to help get a better understanding of the results.

Statistical measurements

For all good peer reviewed trials the results need to be presented with statistical references attached to them. The main statistical factors quoted will be the CV and the LSD. The CV or coefficient of variation is a statistical measure of the dispersion of data points in a data series around the mean (average). Or in other words if the trial has a high CV then there was a lot of variation in the trial and  the results may not be as consistent as you would like. The LSD or least significant difference measures the probability of differences between values. In other words if the trial have a low LSD (p>0.05%) the trial shows that if this trial was repeated 100 times then we could expect the same result in 95 of these trials. Where the results were completed in multiple fields, over multiple years, which will capture different environmental conditions and soils, then these results will come with a high level of confidence that it can be translated to your farm.  

The best way to test a product on your farm

With all that being said what’s the best way for you test a product on your farm? Firstly only test one variable at a time e.g. everything the same except the inclusion or absence of a product to be tested.

Select your most consistent field in terms of soil type and underlying pH, P&K values. Ideally applying the product to different tramlines to generate the best results e.g. apply the product to a tramline A, C, E , with none applied to tramline B, D, F. Care is needed a harvest to ensure you can measure yields from each tramline treatment area. A weighbridge is ideal, or a diet feeders (with weight cells) can be useful, and certainly a GPS yield monitor is the best way to measure these differences.  

What can you expect in terms of a result?

Its hard to come to a conclusion with small yield differences (0.3-0.5t/ha) with these type of comparisons. Where the yields are closer to 1 t/ha then there is a good chance there is something to be gained from the product.  And perhaps re test this again the next year to see if you get the same result..

Farming is a continual learning process and these on-farm trials are a vital part of your farm progression and profitability. If you're going to put in a comparison trial of your farm keep in contact with your advisor, as every advisor will be more than delighted to help you design and monitor the farm trail over the season.  Then everyone will learn from this process!!

Find out more information and advice from the Teagasc Crops team here.   The Teagasc Crops Specialists issue an article on a topic of interest to tillage farmers every Thursday on Teagasc Daily. Find your local Teagasc office here