Moses Lake, WA 98837, USA

Soil erosion a risk at potato, onion harvest time

Staff Writer

MOSES LAKE — It was a brisk wind that swept in from the west that Tuesday in late September.

It wasn’t a bad as past dust storms, but it hit at just the right time, as potato and onion farmers were harvesting. The winds whipped up great clouds of brown dust and carried off what looked to be giant swathes of Grant County and sent them east, toward the Palouse.

Toward Idaho. To points beyond.

“The wind in spring and fall is pretty typical,” said Tracy Hanger, the Washington state agronomist for the U.S. Department of Agriculture’s Natural Resource Conservation Service, which advises farmers and other landowners on how to prevent erosion.

Hanger said the greatest risk of wind in the Columbia Basin is in August and September, and there are some very basic things farmers can do to keep their soil around when the wind arrives, such as plant a simple cover crop to hold the soil in place.

“If nothing else, just get some water on it,” she said.

Both Hanger and Matthew Blua, director of industry outreach with the Washington Potato Commission, said cover crops aren’t an easy option, especially with root crops like potatoes and onions.

Because they aren’t simply cut when they’re harvested — the ground actually has to be torn up to get them out of the ground.

“Soil erosion is a big deal,” Blua said. “Wheat farmers use no-till, and they leave stubble on the ground. But potatoes have to be dug up, there’s no getting around it.”
Hanger said it’s especially important to minimize tillage in dryland farming, where soil managed intensively to maximize stored moisture can yield without irrigation but is also very susceptible to erosion.

“It’s a tough one with root crops,” Hanger added. “Anything that works the soil extensively, stability is lost, and it’s more easily lost because there is no cover.”
However, Hanger said a little tilling “stimulates biology in the soil.”

And most potato and onion farmers do a good job of managing the soil to prevent erosion, Hanger said. The wind just hit at the right time, a little later in the season than usual, before farmers could sow a cover crop.

“There’s not much you can do when you’ve got equipment out in the field ripping up potatoes,” she said.