New Polymer Keeps Soil In Its Place Tests Show Less Erosion, Better Water Retention On Columbia Basin Fields

You could call it the blob that saved Eastern Washington - or at least the blob that saved millions of tons of Eastern Washington soil.

For now, farmers in the Columbia Basin are using the far less racy title of “polymer,” or “polyacrylamide,” or “PAM” for short.

By whatever name, the clear, goopy substance is being heralded as a major tool in saving the tons of soil that wash from irrigated furrows into retention ponds and waterways.

Royal Slope farmer Ray Wardenaar saw the results last summer when he tinkered with the goop on several cornfields.

To be sure, PAM, which is not to be confused with the spray-on cooking oil, at first held little promise of being particularly useful, forming a blob in a tank of water as Wardenaar tried to mix it.

“We were kind of laughing that we hoped it wouldn’t grow and jump out of the tank and take over the community,” he said.

But once he got the solution siphoned from irrigation channels and run through furrows, water left his fields looking so clear “I would almost think you could drink it,” Wardenaar said.

Before, water had run off in a heavy gray, muddy stream, often with deep erosion channels in its wake.

“The results were so visible to the eye as far as soil leaving the field,” he said. “It was absolutely amazing.”

And while PAM cost about $4 an acre, Wardenaar is used to paying roughly 10 times that to clean a retention pond, which now fills with soil far more slowly. He also expects to grow a better crop as water seeps into the soil more uniformly.

With 175,000 furrow-irrigated acres in the Columbia Basin alone, and 25 million more acres throughout the Far West, the potential is remarkable, said Harold Crose, district conservationist for the U.S. Natural Resources Conservation Services in Grant County.

Typically, furrow-irrigated fields lose 10 to 13 tons of soil per acre a year and as much as 50 tons an acre on steep fields. But treated with the polymer, soil losses on test fields like Wardenaar’s were “almost nothing,” he said.

If such results continue, he said, the use of the polymer could be “one of the biggest things to control rill-irrigated erosion that we’ve ever come across.”

Polymers, long chainlike molecules, have been used for decades in food processing and paper production, forcing solids to clump together and settle out of wastewater. With the development of different types of polymers and application techniques, researchers like Rick Lentz and Robert Sojka of Kimberly, Idaho, have found polyacrylamide helps soil particles bond together too, resisting erosion in the process.

Other conservation methods like different tillage techniques and retaining plant residues still are key factors in fighting erosion, said Lentz, a postdoctoral fellow with the Agricultural Research Service. But PAM, he said, “certainly does the job. That much has been proven.

“We’re looking at it as a piece of a whole water management plan, rather than an isolated technology,” said David Granatstein, the statewide coordinator for Washington State University’s Center for Sustaining Agriculture and Natural Resources.

With the success of those tests, said Crose, fertilizer suppliers now are talking about stocking the material, and farmers across the basin are talking about using it.

One possible hitch was cleared earlier this month when the Department of Ecology said the material could be used on a wide scale.

While the material is inert and eventually breaks down into harmless carbon dioxide and water, the department wanted to be sure it would not harm water quality.

So far, it doesn’t appear to, said Charlie McKinney, agricultural water quality specialist for the DOE’s central region.

Meanwhile, soil sediment is one of the biggest water quality problems in the state, carrying pesticides, darkening water and damaging fish habitat, McKinney said, making PAM a promising answer to the region’s erosion problems.