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Expert: Efficiency, not regulation, reducing dairy air emissions

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Oregon’s air quality is predominantly rated as “good” by the EPA, an industry expert said.

SALEM — A desire to reduce inefficiencies — and neighbor conflicts — is driving Oregon dairy farmers to cut unwanted emissions, according to an industry expert.

Environmental activists often bemoan the lack of federal and state air quality restrictions for dairies, but farmers are taking steps on their own, said Troy Downing, dairy extension specialist at Oregon State University.

“As we get new science, our industry is adopting it quicker than we would through regulation,” Downing said at the Oregon Dairy Farmers Association’s annual conference on Feb. 20.

The prospect of Oregon’s government taking a more active role has been raised by Senate Bill 197, which would require the state Environmental Quality Commission to enact formal rules for reducing dairy air emissions.

The legislation seeks to formalize recommendations made by a dairy air task force in 2008, which proponents of SB 197 complain haven’t been acted upon, Downing said.

In reality, though, dairy farms have voluntarily implemented “best management practices” such as installing anaerobic digesters to capture gases and use them for energy production, he said.

“We have made significant progress,” Downing said.

Decreasing odors allows dairy farmers to be good neighbors as well as curtail volatile organic compounds, or VOCs, he said.

The adoption of automated scrapers has led to more frequent removal of manure and urine from barns, Downing said. Waste is more stable in a liquid state, which prevents volatilization and the release of undesirable gases.

Some measures also help farmers put the nutrients in manure to better use.

By applying to manure to fields with “big guns” at high pressure, more of the substance is released as an aerosol-like spray that’s prone to volatilizing into a gas, Downing said.

More farmers are now switching from the big guns to low-pressure or injection systems that preserve nitrogen while reducing gases, he said.

Manure is often assumed to be the culprit in dairy emissions, but feed and silage also release gases, Downing said.

Dispersing smaller amounts of silage several times a day — rather than a large amount once — decreases the amount of time it lays around, reducing VOCs, he said.

Storing silage in a narrower pit also shrinks the size of the open “face” as feed is removed, reducing volatilization of gases compared to a broader pit with a larger face, he said.

As gases are volatilized from silage, the material’s weight decreases, Downing said. “That’s dry matter you’re losing to the atmosphere that the cows aren’t eating, that you bought and paid for.”

Reducing emissions can be advantageous for dairies, but Downing noted that livestock production contributes to only 4 percent of U.S. emissions of “greenhouses gases,” according to the U.S. Environmental Protection Agency. The dairy industry’s share is less than 1.5 percent of total U.S. emissions.

Meanwhile, Oregon’s air quality is predominantly rated as “good” by the EPA, though some areas occasionally dip into “moderate” territory when people heavily use wood stoves during atmospheric inversions, Downing said.

“Oregon really has no air quality problem. What problem are you trying to fix?” he said.

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