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Ag Report


Time to Burn

As researchers continue exploring the benefits of summer prescribed burning, Kansas land managers may be on the brink of a real opportunity to explore this alternative on their own property.

KC Olson ’98, K-State professor of range beef cattle nutrition and management, has been researching the benefits of moving prescribed burning from spring to late summer.

burningOlson’s research began in 2014. The data from that four-year study shows late-summer burning dramatically reduces the incidence of sericea lespedeza, a noxious weed found in at least one-third of the Flint Hills. The plant is known to out-compete native plants for water and nutrients, and it contains high levels of condensed tannins that make it undesirable for cattle grazing.

“We’ve started data collection for a six-year trial, which will involve livestock performance as a primary metric,” he said. “We're going to test the influences of a traditional spring burn, a summertime burn in the August-September interval, and a fall burn in the September-October interval, to see how those options influence subsequent livestock performance.”

Olson hopes to make a significant contribution to the growing pile of data, confirming the benefits of summer burning.

Poor weather conditions this past April prompted some landowners to postpone pasture burning. Many worried that the moisture was inadequate to fuel the lush regrowth, which is the impetus for burning. Olson hopes pasture managers try summer burning.

Spring versus summer

Like a spring burn, you’re still applying fire to plant material. “I recommend people hang their old fire management paradigms on a hook and look at it with fresh eyes, because this is a different animal,” Olson said.

“Expect it to move at about one quarter of the surface wind speed. For example, if the surface wind speed is 10 miles an hour, expect that fire to move at about 21/2 miles an hour. You can walk and keep up with these things.”

In summer, green and growing foliage contains more water. For the people working the fire, as well as neighbors, the experience is less irritating.

“As the fire makes contact, that water flash boils,” Olson said. “The smoke cloud looks dense, more intimidating, but that’s because of all the steam.”

burningTo reduce walking in extreme heat, Olson modified his prescribed fire team. “We’re using more small vehicles – think all-terrain vehicles – to work that fire line. If possible, no one walks more than a few feet to spare our people unnecessary exertion in extremely hot temperatures.”

Olson added that his summer burn teams generally employ fewer people than his spring burn teams.

“The aftermath of a spring fire usually looks like a pool

table – slick, black, and little residual material,” Olson observed. “In the summer, fire intensity is much lower. Chances are most of the above ground vegetation is not going to go away completely. You will see standing green material immediately after the fire passes, and it looks like the fire didn’t have any effect at all. But maybe 48 hours after the fire, what was standing green material the day of the fire is now brown, dead, and top-killed. You’ve just caused the whole plant community to reboot itself.”

While those are the major differences between spring and summer burns, all the rules and ordinances apply. You still have to contact your county government for a burn permit. You still have to advise local emergency management teams of your fire, both before you light it and after it’s out.