Farming Magazine - June, 2010


Forages: Opportunities and Pitfalls of On-Farm Trials

By Everett D. Thomas

The best way to learn if a product or management technique works is to rely on the results of replicated research trials, preferably those from unbiased sources such as a Land Grant Colleges. However, it takes money to do these trials, thereby limiting what can be done and how many testing sites can be used. With the decreasing amount of research funding from both public and private sources, this situation isn’t likely to improve any time soon and will almost certainly get worse.

Properly done, on-farm crop trials can provide localized information to help evaluate a new variety, crop input or management technique. Improperly done, the trial may provide worthless data that either sheds no light on the situation, or worse, leads to incorrect decisions. Following are some suggestions on establishing on-farm trials that can provide useful information.

Simple is better

The best on-farm trial is simple and provides a definitive answer. A good example is the current discussion about whether it’s necessary to condition hay crops that will be ensiled. The question is, “Is this trip (conditioning) really necessary?” You don’t need a mower without a conditioner to do an on-farm trial to answer this question. Mow most of a hay field as you normally would using your mower-conditioner, then, for the last few windrows, decrease the tension on the conditioner rolls so the mowed forage “flows” through the rolls without being crimped or squashed by them. Wait until the rest of the field has reached the appropriate moisture content for ensiling and start chopping. As you chop, take several grab samples from the windrows on either side of the rows you didn’t condition, and then take several grab samples from the unconditioned windrows. Do a good job of getting representative grab samples, then composite them and put them into plastic bags so you have only two samples labeled “conditioned” and “not conditioned.” Then run a dry matter test on each using a Koster Tester or microwave oven. All you’re trying to do is answer a simple question: Does conditioning hay crops increase the rate of drying? If the conditioned sample is lower in moisture (higher in dry matter), the answer is yes; if not, the answer is no. Do this a few times, using different crops and various cuttings, and you’ll have a good idea if conditioning is necessary on your farm.

This isn’t really “research” since there aren’t any replications. If you were to test each of the grab samples independently from several windrows you’d come closer to getting data that could be statistically analyzed, but even that may not qualify it as research. (While I was the agronomist at Miner Institute, it seemed like our director of research was forever saying, “No, Ev, we can’t do it like that or we’ll wind up with data that we can’t properly analyze.” I eventually acquired a better appreciation for the importance of proper statistical design.) In the example of conditioning vs. no conditioning of hay crops, there’s already been replicated research, including two trials by Cornell University agronomists that found no significant difference in drying rate. But, that was other farms, with straight alfalfa. Using the equipment you have, on your fields of alfalfa-orchardgrass (for instance), will your results be similar?

Sometimes these on-farm comparisons happen completely by accident. Two Amish brothers near Lancaster, Pa., discovered that conditioning actually decreased the rate of drying of their alfalfa. They mowed an alfalfa field and had about half the field conditioned when their conditioner broke. (On most Amish farms, mowing and conditioning are done in separate trips.) When they started chopping they discovered much to their surprise that the half of the field that wasn’t conditioned was lower in moisture than the half they conditioned.

On-farm trial pitfalls

Farmers are sometimes tempted to compare two or more corn hybrids on their farm, often with encouragement (and sometimes free seed corn) from a seed dealer. We’ve planted many on-farm corn hybrid trials at Miner Institute over the years, so we have a pretty fair idea of what they can do, and what they can’t. Non-replicated corn hybrid trials have limited use, but that doesn’t mean they have no use at all. Here are a few things to consider:

1. The more hybrids included, the more confusing the results. That’s because more hybrids stretch over more land area, increasing the chances of encountering varying soil types and drainage conditions. Use hybrids of similar maturity, ideally no more than a 10-day spread in relative maturity (RM). Seed dealers may want you to plant a lot of hybrids with a much wider range of RM. Avoid this temptation, even if there’s free seed involved.

2. Be wary of big differences in seed size. Once, we planted three corn hybrids that were going to be ensiled and fed in a lactation trial. We were shocked to find that one of the hybrids had 130,000 seeds per 50-pound unit, about 60 percent the size of normal. Also, the kernels of two hybrids were flats while the small kernels were rounds. It took careful calibration and a slower planting speed with that small seed to achieve a similar population as with the other two hybrids. This was necessary because comparing one hybrid at 28,000 plants per acre to another at 35,000 per acre is like comparing apples and oranges. Don’t fall into this trap.

3. Don’t assume too much. Don’t pay as much attention to modest yield differences as to the relative maturity of each of the hybrids included in a non-replicated trial. In non-replicated trials it takes a big difference in yield to be meaningful, but maturity differences are much more reliable. If hybrid A is well dented while hybrid B is still in the dough stage, chances are very good that this represents a real difference in how these two hybrids would behave if the trial was done another year or in a different field.

Properly planned and carried out, on-farm trials can be an inexpensive and convenient way to evaluate new crop varieties and management techniques on your fields and using your equipment. Expect some interesting and useful results, remembering that there’s a difference between side-by side comparisons and replicated research.

Ev Thomas has worked as an agronomist in New York for 42 years, first with Cornell University Cooperative Extension, then with the William H. Miner Agricultural Research Institute in Chazy, N.Y., including managing its 680-acre crop operation. He continues to work part-time for Miner Institute and is now an agronomist at Oak Point Agronomics. He has a written our Forage column for over 10 years and has been an expert contributor on a number of other topics. Comment or question? Visit and join in the discussions.