The massive burning of grassland in the Flint Hills is an annual tradition in Kansas.

Ranchers have torched the ground for decades and have sworn that the burning must be done during a short time period, usually in late April.

But new research from Kansas State University says that is wrong.

The study by E. Gene Towne and Joseph Craine, both researchers in the Division of Biology at K-State, says that burning outside the late spring time frame has no negative effects for the prairie and may have many benefits.

That means ranchers can burn in the fall, winter or spring.

“It’s going to cause a lot of jaw-dropping because it goes against what is thought to be gospel truth,” said Towne, the fire chief at Konza Prairie Biological Station.

In a typical year, ranchers burn thousands of acres of grassland to reduce undesirable trees and shrubs and enrich the grass for that summer’s cattle grazing.

Based on research from more than 40 years ago, it was thought that the grass had to be burned in late spring.

But Towne and Crain said that research was limited.

Their new study, published in the peer-reviewed scientific journal PLOS ONE, was based on data collected from 20 years of burning at the Konza Prairie Biological Station.

The researchers found that when the prairie is burned in the fall or winter, grass composition and production were not negatively affected compared with burning in the spring.

In addition, grasses burned in the winter or fall had more time to respond to precipitation, and that schedule also resulted in more grass diversity, which is good for cattle.

Also, burning in late spring is bad news for snakes, turtles, prairie chickens and other nesting birds.

And there is the issue of the smoke. Several times, the Kansas City and Wichita areas have broken air pollution limits because of smoke drifting from the intensive burning in spring.

By burning over a wider time frame the intensity of the smoke would be reduced, the researchers said.

Craine said the research provides “wins” for everyone. “Our ranchers win. Our prairies win. And our neighbors downwind of the Flint Hills also win,” he said.

Towne said it also gives ranchers more flexibility on when they burn.

But both researchers say they expect some ranchers will argue with their findings. “People are taught one thing and it is sometimes very difficult to accept data,” Towne said.