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WSU Scientist Recommends Conservation Tillage Options to Curb Blowing Dust

PULLMAN, Wash. — A Washington State University scientist is urging wheat farmers in Adams, Benton, Douglas, Franklin, western Lincoln and northern Grant counties to use non-inversion tillage and delay primary spring tillage until the first week of April or later.

“Farmers who have not yet tilled their soil this spring have had no blowing dust problems,” said Bill Schillinger, a soil scientist at WSU’s Lind Dryland Research Station. He is a member of a team of WSU and USDA scientists that has been developing cropping systems and farming practices to help growers reduce wind erosion in eastern Washington.

Wheat farmers in the region, which receives an average of 12 inches or less of precipitation annually, leave fields fallow (unplanted) every other year to store moisture in the soil for the next crop. Excessive cultivation of fallow fields buries crop residue and pulverizes clods, and is a primary cause of recurrent wind erosion.

“Research has conclusively shown that we don’t need to conduct primary spring tillage in March for summer fallow,” Schillinger said.”Farmers can wait until mid-April without losing any soil moisture. There’s a wide time window.”

This year there’s very little moisture in the soil profile, he said. “Farmers can spray glyphosphate to the wheat stubble and relax. Take the family on a nice spring break. Then, when you conduct primary spring tillage, use a wide-blade V-sweep under cutter type of implement that doesn’t mix and stir the soil.”

He said that research has shown that this approach is economically sound. “In addition,” he said, “by using conservation tillage, we can easily retain 30 percent residue cover throughout the fallow period, which is very effective to control wind erosion.”

Controlling wind erosion and blowing dust has been an issue in the Columbia Plateau, a 50,000-square-mile region in Washington, Oregon and Idaho since farming began more than a century ago. About 3 million acres in Washington are farmed in a wheat-summer fallow rotation.

In addition to soil loss and creating traffic hazards, blowing dust contains small particles ranging from 2.5 microns to 10 microns that can accumulate in the lungs and cause respiratory infections. The 1990 Clean Air Act requires states to monitor and control particulates less than 10 microns in diameter.

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