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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #299189
Title: Controlling Kentucky bluegrass with herbicide and burning is influenced by invasion level

Author
item ERETH, CORIE - Natural Resources Conservation Service (NRCS, USDA)
item Hendrickson, John
item KIRBY, DONALD - Retired Non ARS Employee
item DEKEYSER, EDWARD - North Dakota State University
item SEDIVEC, KEVIN - North Dakota State University
item West, Mark

Submitted to: Invasive Plant Science and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2017
Publication Date: 2/5/2017
Citation: Ereth, C., Hendrickson, J.R., Kirby, D., Dekeyser, E., Sedivec, K., West, M.S. 2017. Controlling Kentucky bluegrass with herbicide and burning is influenced by invasion level. Invasive Plant Science and Management. 10:80-89.

Interpretive Summary: Kentucky bluegrass has been increasing on rangelands across the northern Great Plains which places increased emphasis on finding methods to control its spread. This project evaluated the effect of time of burning, either alone or in combination with herbicide application, on the abundance of Kentucky bluegrass, native grasses and native forbs in the Sheyenne National Grasslands near Lisbon, North Dakota. While time of burning, either spring or fall, did not seem to have a consistent impact on abundance of Kentucky bluegrass, combining burning with glyphosate generally reduced Kentucky bluegrass while increasing native grass abundance. These responses occurred rapidly and were often quite dramatic. However, the longevity of the responses was often relatively short which suggests either more frequent treatment application or changes in management following treatment are needed.

Technical Abstract: Kentucky bluegrass (Poa pratensis L.) is a cool-season perennial grass that is increasing on Northern Great Plains rangelands. The Sheyenne National Grasslands (SNG), located in Southeast North Dakota and one of the last publically owned remnants of the tall-grass prairie are threatened by Kentucky bluegrass invasion. A project was initiated on three sites with different levels of Kentucky bluegrass invasion (77%, 91% and 37% introduced grasses in the species composition for Sites 1, 2 and 3 respectively) in the SNG, to evaluate timing of burning and the combination of burning plus herbicide for controlling Kentucky bluegrass. Four replicated strips (20x60 m) were located per site with half of each strip (10 x 60m) randomly selected to be burned in late October 2005 and the other half in early May 2006. The herbicide treatments of 1) No Herbicide, 2) 2.24 kg/ha of glyphosate and 3) at 0.43 kg/ha of imazapic were randomly assigned to 10 x 20m subplots within each burn. Fifty 10-point frames were taken in July of 2005, 2006 and 2007 to estimate litter, bare ground and basal cover within each subplot. Biomass was estimated from clipping three 31.5 x 15.5 cm quadrats within each subplot in August 2005, 2006 and 2007. All response variables had interactions with year and most response variables had interactions with site. Combining burning with glyphosate generally increased native grass abundance and decreased introduced grass abundance. In heavily invaded sites (Site 2), native grass abundance was increased by nearly six times over initial estimates by fall burning followed by glyphosate. Results with imazapic were more variable and amount of invasive grasses often impacted responses. While burning plus herbicides show promise for use in controlling Kentucky bluegrass, degree of initial invasion and management following treatment need to be considered.