For Release April 17, 2001

Timing of Pasture Burn Very Important

by Chuck Otte, Geary County Extension Agent

The use of controlled burning as a pasture management tool is a very critical and well documented process. The desirable native warm season grasses were periodically burned by nature and native tribal populations for several thousand years. The grasses that remained were those that could tolerate periodic burning.

Over the last century, we have learned a lot about fire in a grassland ecosystem. We have learned what species tolerate fire (grasses) and what species don’t tolerate fire (cedar trees and other woody species). We’ve also learned that fire at the wrong time will suppress growth and production. Fire at the right time will encourage growth and production. This all sounds very simple and straightforward. But in reality, it becomes a very complicated and complex formula to put into practice.

At the time of the prescribed burn, whatever grass species have new growth that is roughly one inch tall will have a competitive advantage. Timing of the burn should then be dictated by the new growth of the desired species. Oh-oh. That puts us at the mercy of the weather! When new growth starts will depend on what kind of year it is. But wait, there’s more to this puzzle!

What grass species do you want to encourage? That’s right, there’s more than one grass species out there and they all act somewhat differently. The two principle grasses, that should make up the heart of any native tall grass pasture, are Big Bluestem and Indiangrass. In highly productive Flint Hills pastures, these two grasses will be the highest yielding and the highest quality grasses out there.

They are also two of the later grasses to break dormancy and start growing in the spring. As of this past weekend, Indiangrass shoots were just coming through the soil surface. If we want to burn when these are about an inch tall, then we are probably looking at around the 21st of April for the ideal burning time... for this year.

So what happens if you burn too early? We do know that earlier spring burning will decrease overall production of the pasture, but it will increase species diversity. It will also decrease woody brush control. Many multiple use recreational pastures will be burned early just to increase wildflowers, etc. Other public land areas may be burned early so that there will be less plant growth and thereby less fuel for wildfires later on. We also know that whatever species have about an inch of growth, at the time of the burn, will increase and become more dominant in the pasture.

I have seen pastures that have constantly been burned early start to convert over to being dominated by species like bluegrass and bromegrass. These are cool season grasses that will not provide that critical summer grazing. Remember the old saying that you reap what you sow? You can burn any time that the sheriff’s office will let you. But then you will have to put up with the consequences of that burn time selection.

If your pasture is too green to burn now, maybe we need to take a look at what species are present. They’ll probably reflect your choice of burning time. Pasture managment isn’t strictly by the calendar and by the book. It’s plant by plant, acre by acre and pasture by pasture. And what somebody else does, may not be the best for you and your pastures.


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