Editor’s note: This is the first of three parts looking at setting up and running an on-farm trial for 2022 — with a look at the basics, the finer points of building the trial and, lastly, analysis of the trial.

Part 2: Maximizing your on-farm crop trial

Part 3: How to analyze on-farm trial results

2022 is shaping up to be a year of higher cost of production and tighter margins for farmers. In this type of environment, many folks want to find innovative products or practices that give them more bang for their buck. However, if history has taught us anything in agriculture, diving into the deep end of a major change can be both scary and financially perilous.

In these situations, trying innovative solutions and methods on a smaller scale is a beneficial way to get a look at potential future investments. On-farm or farmer-led trials are an easy way for individuals to learn how practices, products and equipment will work in their own cropping systems.

The premise behind an on-farm trial is to evaluate production practices under realistic growing conditions with the use of a farmer’s own equipment and cropping inputs. Ultimately, properly designed on-farm trials are used to predict responses to products, practices and technologies on a local level to give more exact data to a given geography.

Designing on-farm trial

Here are seven steps to help you design your own on-farm trial:

1. Keep it simple. Too often individuals attempt to look at multiple things at once and try to draw a conclusion that simply has too many variables to get a good answer. Simple and accurate will give you an answer to the questions where the “kitchen sink” approach will leave you with as many questions as when you started and no answers.

2. Formulate a question. The on-farm trial must be designed to fairly test the question without an outcome bias. Keeping it simple by asking yes-no questions or looking at only one variable is vital. For example, does ultra-early soybean planting increase yields compared to a normal planting date? A fair on-farm trial would use the same soybean cultivar at both the ultra-early and normal planting dates to compare yield.

3. Include a control treatment. Controls are not used to adjust yield results but rather to provide a baseline. The control is the most important part of any trial for comparison and the most left out by farmers. From the example above, the control is the normal planting date (likely early to mid-May for much of Iowa), with the ultra-early planting as the test treatment in question. The control can either be the bulk of the acres planted or the strips left untreated.

4. Randomize and replicate. This helps account for field variability and builds statistical power to detect differences between treatments. Replication is extremely important to understand how much variability exists within the on-farm trial results. The lower the variability the greater the certainty of the results.

Start with a minimum of four replications to account for in-field variability. Splitting a field in half for comparison is not a sound way conduct on-farm trials because the data will not be accurate enough to use in other environments. Replication also helps to avoid bias by not allowing placement of one treatment in a more favorable environment within a field and skewing the results.  

5. Be consistent with management. The saying “You can’t compare apples to oranges” comes to mind. The only management factor to change in the on-farm trial area is the factor being tested. Any other factors that change will confound the results making it hard to determine what caused the outcome.

6. Know the field history. This avoids conducting a trail in an area where variability is high, or something else may affect your results. Conducting a starter fertilizer test in an area that has an extensive manure history may be problematic due to high soil test levels. Place on-farm trials in areas that are uniform or equally account for the variability within each strip. Avoid areas of known high or low productivity if it would insert bias to a treatment.

7. Persuade a neighbor to join trial. There is great benefit in conducting on-farm trials on different farms. The more locations a trial can be conducted, the greater confidence found in the results. Extrapolating on-farm trial data from a single or few locations can be risky. More locations allow for a wider range of environmental conditions to be considered to show the treatment results stand up to more than just one farm.

In the next installment, the focus is on field issues for making the most of the on-farm trial.

Witt is an Iowa State University Extension agronomist based in Guthrie Center.