SALEM — Supporters of a permanent 500-acre limit on canola in Oregon’s Willamette Valley have won half the legislative battle with the proposal’s recent approval in the Senate.

However, opponents still have about two months to try defeating the bill in the House, where it must likely clear a policy committee and a couple legislative deadlines on its way to a floor vote.

Restrictions on canola planting have repeatedly prevailed in the Legislature over the past decade, but Senate Bill 789 would impose the 500-acre cap in perpetuity for the first time.

Earlier sunset provisions prompted lawmakers to periodically revisit the issue, giving canola farmers a chance to argue the maximum acreage should be increased or dropped altogether.

Proponents of making the 500-acre limit permanent claim any additional canola acreage would imperil the region’s specialty seed industry by endangering the genetic purity of related crops.

“The extraordinary premium value of the crops at risk here depends entirely on the market’s trust they’re fully organic and GMO-free,” said Sen. Jeff Golden, D-Ashland. “With expanded canola acreage nearby, our seed farmers have absolutely no way to earn and maintain that trust.”

Though the Senate passed the bill 16-12 along party lines, Golden was the main voice advocating for the proposal and defending it from attacks during the April 10 floor session.

Most Democratic lawmakers who voted for SB 789 remained silent as their Republican colleagues argued it’s an unjustified intervention in the agricultural economy.

“We don’t have to have a government solution all the time. A lot of the time, it’s neighbors working with neighbors,” said Sen. Kim Thatcher, R-Keizer.

Democrats hold majorities in both chambers, which may also bode well for SB 789’s chances in a House floor vote, but the bill isn’t guaranteed to reach that point.

Negotiations over spending often reach a crescendo late in the legislative session, which must end June 25 this year.

As lawmakers rush to wrap up, a bill that handily passes one chamber may still fall by the wayside and end up dying in committee.

Past canola legislation has tended to avoid this fate, however, as the 500-acre limit has been renewed twice since it was created in 2013.

Lawmakers initially allowed canola to be grown on 500 acres to facilitate an Oregon State University study, which eventually concluded the crop poses no greater agronomic threat than other brassica plants.

Restricting canola to this “thumbprint limit” amid the valley’s 3.7 million acres is now groundless, particularly because radish and turnip crops can also pollinate specialty seeds but don’t face similar caps, according to opponents of SB 789.

“There’s nothing unique to canola. This is a bunch of fear-mongering that doesn’t deserve this much attention,” said Sen. Dennis Linthicum, R-Klamath Falls.

Varieties of canola commonly grown in the region aren’t “genetically modified organisms,” or GMOs, and the 3-mile “isolation distance” that prevents crossing between seed crops would allow for far more than 500 canola acres to be planted, opponents said.

“I am not a farmer and I believe a lot of decisions should be left to farmers,” said Sen. Fred Girod, R-Stayton. “Why are we sticking our noses into this?”

Golden said the restriction represents a compromise that remains necessary to protect the high revenues generated by specialty seeds, which allow farmers to thrive even on small acreages.

“We’re talking about one of our state’s most potent economic sectors,” he said.

While the OSU study found canola doesn’t pose an inordinate risk, it focused more on weed, pest and disease issues than the core problem of genetic contamination, Golden said.

The 500-acre limit is specific to the Willamette Valley but it’s not unprecedented, as the state has three other control areas where canola is regulated, he said.

“The suggestion there is no scientific basis for these protected districts just doesn’t stand up to the accumulated testimony on this bill,” Golden said.