Two University of Idaho agricultural scientists are evaluating seven potato varieties under organic production methods.
“There’s a lot of interest and a lot of curiosity by growers,” reports Nora Olsen, a UI Extension potato specialist. “A lot of people are wondering ‘OK, if I were to jump into this, how would it work?'”
The study is sponsored by the Idaho Potato Commission.
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; four fresh market spuds: Yukon Gold, Red Norland, Norkotah and Norkotah-8.
Idaho’s mainstay potato variety, Russet Burbank, is also under observation in the organic test plot.
The planting will be watched for pest problems. Only organic type materials such as Spinosad will be used to control potato beetles.
Before planting, the experimental plots were fertilized with dairy manure or dairy compost and fish emulsion.
Two monumental problems faced in organic production are weed control and fertilizer.
“It’s a new challenge for us and we’re learning,” says Olsen. “There are a lot of potatoes grown in this area and consequently there will be plenty of potato pests. We could have all the same problems than neighboring conventional growers do, and we’ll need to deal with those problems in a modified way.”
The team says a big challenge is making sure the potatoes get the nitrogen needed during the critical vine-ripening and tuber-bulking stages. Conventional producers typically apply pre-determined levels of nitrogen fertilizer at planting, followed by measured supplementary applications through sprinklers during the growing season.
Much of the nitrogen in the manure and compost applied to the organic plots must be converted by soil microbes into forms plans can use, a slower and less precise practice, notes Olsen.
The study reflects an increase in organic potato production in Idaho, which produced such crops on nearly 1,200 acres this year, up from about 500 acres a year earlier, mirroring a steady annual increase.