Twin Falls, Idaho
June 26, 2008
To help Idaho potato growers meet
the market demand for organic spuds, two
University of Idaho
agricultural scientists are evaluating seven varieties of
potatoes under organic production methods in a one-acre field at
Kimberly.
“There’s a lot of interest and a lot of curiosity by growers,”
said Nora Olsen, University of Idaho Extension potato
specialist. “A lot of people are wondering, ‘OK, if I were to
jump into this, how would it work?”
Olsen and Extension soil specialist Amber Moore are digging up
answers in order to make science-based information available to
Idaho producers. This year, they planted two varieties of
processing potatoes—Alturas and the late blight-resistant
Defender—alongside four fresh-market potatoes—Yukon Gold, Dark
Red Norland, Norkotah and Norkotah-8—and Idaho’s mainstay Russet
Burbank.
They will monitor the potatoes closely for pest problems and
treat damaging levels of Colorado potato beetles with the
organically approved pesticide Spinosad. Before planting, they
fertilized some of their experimental plots with dairy manure
and others with dairy compost and will add fish emulsion—and
possibly humic acid—during the growing season.
“Two of the biggest challenges that organic farmers face are
controlling weed pressure and effectively managing plant
nutrients,” Moore said.
The scientists expect to cultivate at least four times for
weeds, including one early-season pass that proved necessary for
volunteer alfalfa. The field—undergoing transition to full
organic status—had been in alfalfa the past two years.
“It’s a new challenge for us and we’re learning,” said Olsen of
the Idaho Potato Commission-supported project. “There are a lot
of potatoes grown in this area and consequently there will be
plenty of potato pests. We could have all of the same problems
that neighboring conventional growers do, and we’ll need to deal
with those problems in a modified way.”
Olsen and Moore say that making sure their potatoes get the
nitrogen they need during the vine-ripening and tuber-bulking
stages could be the biggest challenge the scientists face.
Conventional growers typically apply pre-determined levels of
nitrogen fertilizer at planting, then follow up with precisely
measured supplementary applications through their sprinkler
systems during the growing season. But much of the nitrogen in
manure and compost must be converted by soil microbes into a
form plants can use—a slower and less predictable process.
Moore will take numerous samples of soils and plant tissue this
summer to determine when nitrogen is becoming available to the
plants and whether it’s available at sufficient rates. She and
Olsen will also compare the potato varieties to see which
perform best under organic production methods: some may produce
larger canopies and shade weeds more effectively, while others
stand up better to insects or diseases, tolerate more
competition from weeds or use fertilizers more efficiently.
They will also track costs, yields and crop quality and compare
their crops with conventionally grown potatoes to help Idaho’s
increasingly interested growers assess the pros and cons of
organic production.
According to Margaret Misner, organic program manager for the
Idaho State Department of Agriculture, Idaho growers are
producing 1,176 acres of organic potatoes in 2008, compared with
495 acres in 2007 and 157 acres in 2006.
Founded in 1889, the University of Idaho is the state’s
flagship higher-education institution and its principal graduate
education and research university, bringing insight and
innovation to the state, the nation and the world. University
researchers attract nearly $100 million in research grants and
contracts each year; the University of Idaho is the only
institution in the state to earn the prestigious Carnegie
Foundation ranking for high research activity. The university’s
student population includes first-generation college students
and ethnically diverse scholars. Offering more than 150 degree
options in 10 colleges, the university combines the strengths of
a large university with the intimacy of small learning
communities. For information, visit
www.uidaho.edu. |
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