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Corn+Soybean Digest

Trial Run: Test-ifying at Home

Before Tom Oswald adopts a new farm product or practice, he likes to take it for a trial run — or two, or three.

The Cleghorn, IA, grower has been conducting multi-year, replicated on-farm trials since the late 1980s. Using side-by-side strip tests, Oswald has compared tillage methods, fertilizers, fungicides, aphid controls and nitrogen (N) rates. “Every farmer has different resources,” Oswald says. “With strip trials, you can take an idea from somewhere else and see if it works locally.”

Oswald's on-farm trials have given him the confidence to make significant management changes, especially in tillage.

After several years of side-by-side trials, for example, Oswald converted to no-till soybean production. “The tilled strips just weren't paying their way,” he says. He did similar multi-year trials before shifting to strip-tilled corn in 1995. “As we continue to tweak our system, strip trials are helping us make it even better. I'm finding that very rewarding.”

On-farm tests can be a great way to see how a product or agronomic method performs in your specific circumstances, says Greg Shaner, Purdue University plant pathologist. “If done correctly, on-farm research can provide a lot of useful data.”

ON-FARM TRIALS also complement university small-plot trials, says Jodi DeJong-Hughes, a University of Minnesota regional Extension educator who teaches farmers how to set up valid trials. “Problems emerge in fields that don't come up in small-plot trials,” she says.

Shaner agrees: “Although a lot of new technology in agriculture comes out of small-plot research, many farmers are skeptical that information from plots measuring less than 300 sq. ft. can apply to large fields. Actually it does.” Still, he acknowledges, “farmers seem more inclined to believe results” from farm-scale trials using commercial planters, sprayers and combines.

There's a lot more interest in doing on-farm research, now that GPS and yield monitors have made it easier to manage trials, says Mick Lane, a spokesman for the Iowa Soybean Association's On-Farm Network. The On-Farm Network provides detailed strip-trial protocols and helps growers analyze test results. More than 400 Iowa farmers planted replicated strip trials last season through the program, Lane says.

Participants have tested a wide range of corn and soybean technologies and production practices, he says, including N rates, insecticides, soybean inoculants, fungicides, lime applications, seed treatments and deep ripping.

Tom Oswald, for example, has done three years of side-by-side fertilizer trials on strip-tilled corn. In 2005, 2006 and 2007 he tested the efficacy of applying sulfur and N at planting. “Adding fertilizer with the planter is a bit of a hassle and I wanted to test to see if it was worth it,” Oswald says.

HE SET UP five or six replications per test. Treated strips received a mix (20-0-0-13S) of 28% N and ammonium thiosulfate placed in a shallow band beside the furrow. He ran the trials on different fall-applied N fertilizer base rates. Yield improvements in the treated strips varied year to year, Oswald says, but overall, the fertilizer delivered enough advantage that “we're going to continue the practice. We feel it's worth the hassle.”

Underwood, MN, farmer Mark Schoening tunes into new ideas by running University of Minnesota Extension trials on his farm. “Farming is so competitive now,” says Schoening, who has farmed since 1981. “It's not always easy to find someone to share notes with.”

On-farm trials “take extra time, and that's one of the toughest parts. But the information gathered is worth it,” he says.

Collaborating with Extension specialists Doug Holen and Ian MacRae, Schoening has done replicated soybean aphid management trials since 2002, when the new pest first showed up in western Minnesota. “We did some of the pioneering research on Mark's place,” Holen says. Schoening's on-farm trials demonstrated the effects of treatment timing on aphid control and helped establish economic thresholds.

Holen and Schoening work together throughout the growing season to manage the research. Holen and MacRae plan the trials, help select the test locations and set up the strips. “It needs to be done right or it doesn't count,” Schoening says. He plants, sprays and harvests the field-scale trials using his own equipment. They use weigh wagons to measure test-strip yields.

Doing trials on Schoening's farm “gives us instant credibility with other farmers,” Holen says. “And Mark helps us spread the word” about new management practices. “He gets a lot of calls from other farmers interested in what he's doing.”


Split-field, single-strip or field-to-field comparisons are not a valid basis for decisions. Be sure to set up your on-farm trials correctly so you can bank on the results.

The key principles are replication and randomization, says Purdue University Plant Pathologist Greg Shaner. Treated and check strips must be repeated at least three times in the field. And treatments should be assigned to test strips at random to avoid selection bias.

He suggests growers sit down well ahead of planting season with their local Extension agent or agronomist to discuss the setup. These professionals can also help you statistically analyze the data to determine if variations are due to chance or the treatment. Here are some tips on how to manage your on-farm trials:

  • Test only one variable. Always include comparison check strips that represent your normal practice. Treated strips should be managed exactly the same as control strips, except for the treatment or practice being tested.

  • Repeat the trials three or more times. The most valuable data comes from several sites and multiple years.

  • Assign treatments randomly to each block of strips by flipping a coin or drawing numbers from a hat.

  • Select uniform test sites. Consider previous cropping history, drainage, soil characteristics, topography, pests and bordering influences, such as trees, fences and runoff. Iowa farmer Tom Oswald, who has done on-farm trials for two decades, lays out his test strips perpendicular to known field variations. “Gear strip width to your combine width, with enough strip length so you can run the combine at calibrated flows,” Oswald advises.

  • Keep good records. Mark strip locations with GPS coordinates or flags, or both, says Mick Lane of the Iowa Soybean Association's On-Farm Network, which helps farmers conduct on-farm trials. “Flags can be knocked down by field operations, and GPS storage can fail,” he says.

  • Make observations and take notes about soil moisture at seeding, planting conditions, soil fertility, weather, insects, weeds, diseases and crop growth and development. Gathering data such as plant height and “greenness” can also be helpful. “In-season observation of crop conditions really helps interpret the yield data,” Shaner says.

  • Measure yields with a weigh wagon or yield monitor. If you're using a yield monitor, make sure to correctly calibrate it for conditions in the test field. Jerry Danford, Jr. of LaCrosse, IN, ran fungicide trials in corn and soybeans on his land in 2007. “We harvested the middle of each strip first,” weighed the grain from each swath, then finished combining the rest of the rows, he says. “It worked well.”

  • Analyze the data. Statistics software is widely available. Or, your local Extension office can help you interpret the results. “If the means are far apart, the results may be obvious,” says University of Minnesota regional Extension Educator Jodi DeJong-Hughes. “But usually, you will need a statistical analysis.”


Gary Wagner likes to know precisely what works on his farm. Wagner farms near Crookston, MN, with his brothers Wayne and Daryl. The family raises soybeans, edible beans, sugar beets, spring wheat and confectionary sunflowers on 5,000 acres in the Red River Valley.

Gary also teaches precision agriculture management at the University of Minnesota, Crookston.

Precision farming tools make it easy to set up valid on-farm comparisons and collect the results, he says. And data from his own fields helps him make better decisions.

The Wagners bought their first yield monitor in 1993 and started variable-rate fertilizer applications in 1997. Today, “we use most of the precision tools out there,” Gary says, including GPS and yield-mapping, auto-steer, elevation mapping, high-resolution aerial imagery and map-based prescriptions. They have John Deere's GreenStar2 control system, Harvest Doc software and AutoTrac guidance with Deere's StarFire RTK receiver.


They have done a wide variety of side-by-side comparisons on their farm. A couple of years ago, the Wagners did trials of strobilurin fungicide on soybeans. They saw “no yield response” on their farm that year, Gary says, but because product performance varies year-to-year, he wanted to take another look. In 2007, he tested the fungicide again on three different soybean varieties in four separate fields.

Gary set up a randomized block pattern consisting of eighteen 100-ft.-wide strips in each field, for nine side-by-side pairs. Using a 90-ft. spray boom, “I would spray a strip, skip 100 or 200 ft., spray another strip, and continue that way all across the field. By doing strips across the field, you get away from the bias of treating just the best part of the field,” he says.

For the last two seasons, the Wagners have also done strip trials of chelated iron to correct iron deficiency chlorosis (IDC) in soybeans. IDC is a big problem for the Wagners, who grow about 1,500 acres of beans a year.

In 2007, the Wagners did nine side-by-side iron fertilizer replications in a 160-acre soybean field that had chlorosis-prone pockets. The iron fertilizer manufacturer provided the product at no charge. Gary applied it at planting time on 100-ft.-wide strips running the length of the field. Adjacent check strips were left untreated. In calcareous patches, the treated plants yielded better and matured faster than those in the check strips, Gary says. But in non-calcareous soils, treated plants showed no improvement over untreated plants, he says.

These trials convinced Gary that iron fertilizer “has a place in our soils and cropping rotation,” particularly for “racehorse varieties” with high yield potential and low IDC tolerance. “But it's very expensive - $18-30/acre,” he says.

The Wagners are working with Brad Van De Woestyne of John Deere Ag Management Solutions to identify chlorotic areas where it would be profitable to apply iron fertilizer. Van De Woestyne helps growers use their precision-ag tools “to quantify where a practice pays and where it doesn't, and to use that data to refine management.” Results from the Wagners' on-farm trials will be used to generate variable-rate prescription maps to guide chelated iron applications, he says.


It's certainly feasible to conduct valid on-farm trials without precision-management tools, Gary notes, but it takes more time. The test strips have to be flagged by hand, and at harvest, the grain from each strip has to be dumped, weighed and recorded separately. “You could end up losing the data if the weather doesn't cooperate and you don't have time to use the weigh wagon for each strip,” he says.

By contrast, the GPS system records test-strip locations, and yield monitors let you collect test-strip data while harvesting continuously. “You can farm just like you always do and look at the data later,” Gary says. “You're not spending extra time.”

On-farm trials are easier with precision ag tools, adds Van De Woestyne, and “they are another way to find additional value in precision-ag tools.”

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