Wyoming Restoration Challenge – Weed Control Freaks Update

Wyoming Weed Science Control Freaks Update:  Our team has been busy over the past few months with classes and traveling across the country and abroad presenting research. The Wyoming Weed Science Control Freaks team consists of Carl Coburn, Clint Beierman, Clay Wood, and Julia Workman – all graduate students in the weed science group at the University of Wyoming.

The Wyoming Weed Science Control Freaks plot was dominated with cheagrass, 2015 cover data showed 93% cheagrass cover. There was some alkali sacaton, western wheatgrass, and threadleaf sedge present, but in very limited amounts in terms of cover. Other annual weeds present in small amounts included kochia and tumble mustard.

We took a fairly aggressive approach to cheatgrass management and have utilized many control techniques to suppress cheatgrass to limit seed production in 2015 and to prepare the site for seeding of a perennial seed mix. Essentially we are hitting the “reset” button on our plot with this broad approach to cheatgrass management. We applied glyphosate herbicide (Roundup Powermax) at a rate of 22 oz./acre on April 14, May 18, and October 21, 2015. Herbicide applications were done using a ten foot boom hand sprayer. These early and late applications of glyphosate were intended to reduce cheatgrass at a time when perennial grasses were not actively growing to minimize damage to these desirable grasses.

On August 11, 2015 we used a propane torch to burn the plot to remove the dense cheatgrass litter cover that had accumulated on the site. The burn was fairly successful at reducing litter cover, however there were some annual pigweeds that grew later in the season that were not well controlled by fire. As a result, we decided to mow the plot to remove these pigweed stalks and other standing material that was not burned.


Carl Coburn burning the Control Freaks plot.


Clint Beierman making sure the fire stays contained.

In early December the plot was disked to break up the heavy compaction layer in the soil that was present approximately one inch below the soil surface. We wanted to break up this compaction layer to prepare a better seed bed for our permanent seed mix and to increase water infiltration in the soil profile. On December 14, 2015 we seeded our plot with two seed mixes. One was broadcast seeded and consisted of a mix of perennial grasses, forbs, and shrubs. We then drill seeded crested wheatgrass in rows approximately 18 inches apart. Crested wheatgrass was plated in rows as it is quick to establish and competes well with cheatgrass and the rows will potentially act as a nurse crop for the other seeded species. We did not want to have a large amount of crested wheatgrass in the plot to allow other species to establish and increase diversity of species, but wanted to have an aggressive species present that would provide competition with cheatgrass.


Julia Workman calculating seeding rates to accurately calibrate the plot seeder.


Clay Wood seeding the Control Freaks plot.

We will continue to monitor the establishment of our seeded species in the coming summer and develop further strategies to control any remaining cheatgrass that may have survived the various treatments we have incorporated. Stay tuned for further updates!