Agriculture

Patch burning may be part of the solution

Patch burning has been around for decades, but no one can say if it creates less smoke than the traditional method of burning an entire pasture.

That's never been studied.

"I've never tried to think of it in that way," said Bob Hamilton director of the Tallgrass Prairie Preserve in the Flint Hills in northeastern Oklahoma, who first began patch burning in the late 1980s.

On the preserve, he oversees about 35,000 acres of patch burning — 11,000 for cattle and 24,000 for bison. His task is to increase plant diversity and improve wildlife habit, which is why patch burning was developed.

Simply put, patch burning is burning one-third of a pasture each year, then grazing on that third. The burning is rotated to the next third the following year. So far, research on patch burning has largely been limited to improving wildlife habitat.

Kansas State University recently began examining the method, though mostly as it relates to weight gain of cattle. Grass from burned pastures is more nourishing.

Jane Koger has done patch-burn grazing on 2,700 acres of her 4,000-acre Flint Hills ranch in Chase County since 2003. She said it's about time someone researches its effect in terms of smoke.

The Flint Hills' annual spring burns are creating concerns about ozone pollution as federal regulations continue to tighten air quality standards.

"I believe (patch burning) could be part of the smoke management plan," said Koger, who has been ranching for 30 years. "But we need the research to prove it. I wouldn't be afraid for the research to be done."

She thinks she creates less smoke with patch burning than during the years when she burned all of her pastures every year.

Figuring out how much smoke is produced also isn't the chief aim for Brian Obermeyer, director of the Nature Conservancy's Flint Hills initiative. Since 2006, he has used patch-burn grazing for cattle on about 4,000 acres at the 11,000-acre tallgrass preserve.

"It sounds like if you burn two-thirds less you would have two-thirds less smoke," he said, "but it's not the same. You're still burning three years worth of fuel accumulation in that one-third patch."

Obermeyer suspects he's creating less smoke on his patch-burn acres.

"But is it 10 percent less, 20 percent? I don't know," he said. "The problem is, we don't have good data. We can't say this is the magic bullet for smoke."

Obermeyer said patch burning in a "broad way attempts to mimic some of the historic burning and grazing."

Like the bison before them that were drawn to grazing on grass that grew from burned areas — often because of lightning strikes — cattle naturally move to the one third of the pasture that has been burned.

"They're as smart as a whip," said Clenton Owensby, a range management professor at K-State.

KSU is doing research on patch-burn grazing. Dale Lanham, extension agent in Woodson County, is in his fifth year of a patch-burn project on 640 acres.

"Our (weight) gains have been very, very similar (to those grazing on fully burned pastures)," Lanham said.

The U.S. Department of Agriculture has a program now in its second year that pays producers $30 an acre to reduce fire frequency. Patch-burn grazing fits the requirements.

But the method has its doubters.

Lanham said the process takes a lot of extra work and can be more expensive than traditional burns. Often times fire breaks have to be created in the middle of the pasture and more equipment is required.

Owensby said patch burning is the same as burning once every three years, which he said isn't sufficient to control woody species.

But Koger said it shouldn't be all about weight gains and worrying about every woody plant in a pasture.

"Is it all for the sake of a Big Mac?" she asked. "Do you have to get every ounce of production? Or can you get a good production and keep the ecosystem (working well)?

"If I have 4,000 acres and 40 acres of woody species, is that bad?"

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