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PFI: Variety trials work for veggie growers

By Staff | May 24, 2016

TIM LANDGRAFF, of One Step At A Time Gardens, in Kanawha, poses during October 2015 in the bell pepper test plot on his operation.

AMES – For backyard and hobby gardeners, the colorful photos and eloquent descriptions found in today’s seed catalogs can be an enticing means of choosing what to plant.

But for many commercial fruit and vegetable producers, those details are insufficient for making major decisions about which varieties to grow for their businesses.

Often, these descriptions are not specific to Iowa – and they rarely account for a farm’s unique growing conditions or management practices.

To address this information gap, five Iowa fruit and vegetable growers conducted on-farm research in 2015 comparing the performance of two bell pepper varieties on their farms.

This summer, these farmers are expanding their research to assess summer broccoli, determinate tomatoes grown in high tunnels and annual flowering herbs for pollinator health.

This research, conducted in partnership with Practical Farmers of Iowa, is yielding valuable data on how different varieties perform in Iowa growing conditions, soil types and management systems, and arming Iowa fruit and vegetable growers with data they need to make informed business decisions.

Participating farmers include Rick Hartmann, of Small Potatoes Farm, in Minburn; Susan Jutz, of ZJ Farms, in Solon; Tim Landgraf, of One Step at a Time Gardens, in Kanawha; Alice McGary, of Mustard Seed Community Farm, in Ames; and Mark Quee, of Scattergood Farm, at the Scattergood Friends School, in West Branch.

“Field trials have been hugely advantageous to my farm operation,” Jutz said, who conducts on-farm research on her own and with PFI. “I can make data-based decisions rather than anecdotal decisions.

“I can read all the information I want from Johnny’s or other seed catalogs, but how does it work in my system? The only way to answer that question is to run a trial on our farm.”

Bell pepper study

The two bell pepper varieties studied in 2015 – Olympus and Revolution – were chosen by the farmers because of positive farmer experience, the similarities between the two, and the availability of organic and untreated seed.

Participants planted four replications of each pepper variety in randomized pairs of research plots. Specific management details – plant spacing, mulching, irrigation, harvest frequency and disease and pest management practices – were decided by the individual farmers.

While this set-up meant average end-of-season yields differed by farm, which was an expected finding, certain distinct trends emerged. Three farms found that Revolution produced heavier and more peppers, while two farms found no difference in yield.

When all farms were analyzed together, Revolution yielded significantly more than Olympus (an average of 4.3 pounds per plant for Revolution to 4.03 pounds per plant for Olympus).

The full research report – “Bell Pepper Variety Trial-Olympus and Revolution” is available online at practicalfarmers.org/member-priorities/horticulture.

ZJ Farms was one of the farms that found no yield difference between Revolution and Olympus. Jutz said both underperformed compared to Ace, her preferred pepper variety. However, she explains this is due to her specific management practices.

“If we used Revolution or Olympus, we would have to adjust our system” Jutz said. “They didn’t perform in our system the way Ace does. If we wanted to go to a big green bell pepper, such as Revolution or Olympus, we now know how to do that.”

Future field day

Encouraged by the utility of the bell pepper variety trial’s farm-specific data, the same farmers are expanding their focus to examine other crop varieties.

This summer, they, and additional farms, are conducting on-farm research to learn which broccoli variety performs best as a summer product in Iowa (harvested primarily in July and August); which determinate tomato variety performs best in high tunnels; and which of three annual flowering herbs is most attractive to pollinators.

Tim Landgraf and Jan Libbey, of One Step at a Time Gardens, are participating in this new research, and will host a free PFI field day on Aug. 14 to share preliminary results and highlight the process and importance of their on-farm research.

“We participate with PFI because we gain even more insights working through the experience together with other farmers,” Langraff said. “Also, by having data from other producers across Iowa, we get a glimpse of how robust the conclusions are.”

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