Time for prescribed burning of cool-season pastures is near

In just another month or so, it will be time to start conducting prescribed burns on cool-season pastures. Temperatures have been mild in southeast Kansas, and soils have good moisture. This could cause some of the cool- season pastures starting to green up earlier than normal.

The key reasons for burning cool-season pasture are to remove heavy accumulations of mulch or old growth and to control eastern redcedar.

Cool-season pastures, such as tall fescue and smooth bromegrass, are normally burned in late February or March, if soil moisture is good. If the grass is green and starting to grow, producers could start burning cool-season pastures by mid-February. Cool-season grasses should have about one to two inches of new growth before burning. At this stage, the plants are able to regrow quickly.

Warm-season range grasses will not start growing until later in the spring, regardless of how warm the winter temperatures are. The time to burn native warm-season grasses depends upon your goals.

Increased livestock gains and brush control are normally enhanced by burning in the mid- to late-spring when the native grasses have an average of 1/2 to 2 inches of new growth. Ideal dates may be shifted as much as 10 days before or after April 10, depending on temperatures. Additionally, the soil profile should have adequate water at the time of burning and the surface should be damp.

Other reasons for burning include improved livestock distribution, wildlife habitat enhancement, maintenance of CRP stands, and conservation of native plant communities. Timing for these purposes is more flexible and can be done earlier. CRP should be burned between February 1 and April 15.

With no burning over the long term, the cover of woody plants increases by about one percent per year initially, but then accelerates such that prairie grasses and forbs can be completely displaced by 100 percent tree and shrub cover in less than 40 years.

The effect of burning on undesirable woody plants and forbs will vary, depending on the growth habit. In general, plants are more easily killed by burning when their growing points are aboveground, are unable to resprout from belowground, and their food reserves are at the lowest point.

Burning readily kills eastern red cedar, especially when it is less than five feet in height. It does not have buds that can resprout, so when this plant is defoliated, it dies. Larger cedar trees will generally not be killed by fire and must be cut at ground level to be controlled.

Buckbrush (coral berry) or sand plum must be burned in late spring for two to three consecutive years for effective control. During late spring, these plants are actively growing and fire destroys the topgrowth. Regrowth is slow since its food reserves are low. Successive burns prevent buildup of food reserves and eventually kill the plant.

Western ragweed and western ironweed are perennial forbs, which can also be reduced with two or three consecutive late-spring burns.

Smooth sumac has a life cycle similar to warm-season grasses in that it doesn't reach the lowest point in its food reserves until late May or June. Burning in late spring will kill the topgrowth, but results in an increase in the number of stems that resprout from belowground buds. The net result is that smooth sumac will actually spread more rapidly as a result of late-spring burning.

This article was adapted from an E-Update piece written by Walter Fick, Range Management Specialist for K-State Research and Extension.

Editor's Note: Delta George is a K-State Research and Extension agriculture and 4-H extension agent assigned to Bourbon County. She may be reached at (620) 223-3720.