Research studies by Kansas State University have shown that late summer and fall fires provided significant reductions of Sericea lespedeza and old-world bluestems which are both invasive species impacting rangeland across Kansas.

K.C. Olson, professor of range beef cattle nutrition and management and a team of other researchers from Kansas State University conducted a six-year experiment between June of 2018 and August of 2023 to evaluate the effect of timing of prescribed fire both to plant species composition and yearling cattle performance on Kansas Flint Hills rangeland.

Pastures were burned annually at one of three timeframes over the study. The first timeframe was at a traditional prescribed burn time in early April. The second timeframe was at the end of August.  The third timeframe was in early October.  Pastures assigned to each treatment were burned at the same time annually in years 1,2,3 and 5 of the experiment. None of the pastures were burned in year four of the study due to unfavorable burning conditions.

Research findings

Research results showed a slight advantage to cattle grazing performance for the summer 90-day grazing period following an April burn, where cattle gained 213 lbs. on average. For cattle grazing pastures that had been burned the prior late summer or fall, cattle gained 202 lbs. and 199 lbs. respectively when cattle grazed pastures burned the prior August or October. In terms of plant species composition, pastures burned in the fall showed an increase in native forb species and nectar-producing forbs that are important for grassland-obligate invertebrates and the native birds that feed on them. In this study early October fire increased native plant diversity.

Previous studies have shown that late summer and fall fires can reduce Sericea lespedeza by impacting plant vigor and seed production. This study demonstrated that late summer and fall fire can be utilized with minimal impact to yearling cattle grazing performance while offering grassland managers the opportunity to burn when conditions are typically more favorable. Humidity levels in late summer and early fall tend to be higher and average wind speeds tend to be lower as compared to spring weather.  This type of weather gives greater windows of time for when conditions are favorable for a prescribed burn.

For more information on this study, see the Kansas State University 2024 Cattlemen’s Day Research Report, “Long-Term Effects of April, August or October Prescribed Fire on Yearling Stocker Cattle Performance and Native Rangeland Plant Composition in the Kansas Flint Hills.”

Using fire to control Caucasian bluestem

In a second study, on native grass sites near Kanopolis, in Elsworth County Kansas, a research project was conducted to see if late summer prescribed fire (August 1 – September 21) may provide the opportunity to control invasive Caucasian bluestem.  Plots in this study were heavily infested, containing a prevalence ranging from 65 to 78% Cacuasian bluestem at the start of the study. Treated plots were burned once in 2019 or twice, in 2019 and in 2021. These burned plots and the prevalence of the invasive Caucasian bluestem were then compared to adjacent plots that were not burned.

Research findings

For plots burned only in 2019, three years later there was no difference in the amount of invasive Caucasian bluestem when compared to unburned plots. However, for plots burned in 2019 and in 2021, there was a substantially lower plant population of Caucasian bluestem, reducing it from 65% to less than 50%. Simultaneously, there was an increase in other native species.  For more information on this study, see the Kansas State University 2023 Cattlemen’s Day Research Report, “Effects of Late-Summer Prescribed Fire on Botanical Composition, Soil Cover and Forage Production in Caucasian Bluestem-Infested Rangeland in the Kansas Smoky Hills: Year 4 of 5.”

Possible Nebraska applications for these prescribed burn research findings

These two studies provide insight into the opportunity for the strategic use of prescribed fire at different times of the year, other than spring, on pastures and rangelands in Nebraska. Recently there has been a significant increase in the use of prescribed fire to help control eastern red cedar on rangelands and pastures. Almost exclusively, these prescribed fires occur in the spring of the year.  In parts of Nebraska where humidity is higher, weather conditions in late summer or early fall may offer the opportunity for late summer prescribed burns to be utilized. The potential to use late summer and fall prescribed burns to control eastern red cedar and other invasive plants would increase the window of opportunity for when this tool could be applied.