Water & Sun

Published online: Jan 16, 2021 Articles, Irrigation Tyrell Marchant, Editor
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This article appears in the January 2021 issue of Potato Grower

SunRain Varieties is not your typical Idaho potato grower. The farm’s location near Driggs, Idaho, in the shadow of the Tetons, creates a different natural and social environment than that faced by farmers farther west on the Snake River Plain. And growing their product—high-value specialty potato varieties, many of which are marketed as mini potatoes—are a far cry from production of the big russet processing varieties that are the bastion of the state’s potato fame.

“What we grow is a high-value crop,” says SunRain general manager Brit White. “We have specialized storage and equipment for all of it. So we’ve already made a big investment in specialization.”

All of which got White to thinking: We’re already different; why don’t we try irrigating differently? Drip irrigation had intrigued White and the SunRain team. The significant investment such a method requires, they reasoned, could potentially be offset easier by their high-value mini potatoes than a crop of russets. White reached out to his contacts his former employer, J.R. Simplot Company (which actually has several years’ worth of trial data on drip irrigation in traditional processing varieties), to ask for advice. To his surprise, Simplot’s response was to lend SunRain some installation and filtration equipment, along with a bit of free coaching, to get its own trial underway.

In the spring of 2020, SunRain installed Netafim drip line on a four-acre section of a field planted in Cecile, a red-skinned, yellow-fleshed fingerling potato variety. The rest of that field, also growing Cecile, was irrigated by wheel lines, making for an easy side-by-side comparison. And boy, did they see a difference.

“The potatoes irrigated by drip line required 20 to 30 percent less water. The drip runs at 10 gallons per minute versus 50 or 60. That’s a good sustainability story to tell,” says White. “We also see less stress on the potatoes because they’re simply getting watered better.”

That’s important, White says, because a high tuber set for mini potatoes is so important. When a lot of these varieties are stressed, they commonly drop a set, which is a major problem for the grower. Drip-irrigating ensures more consistent application and placement of life-giving water—and nutrients as well, if drip chemigation is utilized.

“We saw plant-available nitrates in the trial section of the field double what they were in the rest of the field—with exactly the same application of fertilizers,” says White. “We believe the wheel lines are washing a lot of the fertilizer down below the plant root, but the drip lines keep it there.”

The 2020 trial showed enough promise that SunRain plans to test drip irrigation on its farm for at least another year. White expects the practice to prove worth the investment, and says that while it may not be advisable for every operation, he thinks more growers would be wise to look into it as well. 

“We have a lot more to learn,” he says, “but there are strong indications that we can make a lot of the money back in labor and fertilizer savings. In the specialty potato world we live in, a 15 or 20 percent increase in marketable yield is a significant increase in dollars—enough to justify the drip system and then some.”

For a company like SunRain, whose primary business is doing something unique—marketing proprietary varieties that aren’t grown many other places, if any, in North America—looking at a technological investment like drip irrigation comes naturally.

“The nature of our business is such that what might not work somewhere else could work for us,” says White. “Sustainability is important to us, and we’re always trying to be progressive and cutting-edge.”