LRES M.S. Thesis Defense
- Tuesday, November 14, 2017 at 1:00pm
- Plant Biosciences Building, 108 - view map
Optimizing Non-native Annual Brome Control with Herbicides and Facilitating Wyoming Big Sagebrush Establishment in Degraded Drylands
The degradation of drylands, including the invasion of non-native annual bromes is a major problem throughout the Intermountain West. Most restoration efforts rely on establishing desired species from seed, but success is limited and establishing Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) is especially failure prone. This study focuses on developing methods for controlling annual bromes, specifically cheatgrass (Bromus tectorum) and Japanese brome (Bromus japonicas), and successfully re-introducing native sagebrush steppe species to degraded drylands in the Northern Great Plains.
In a greenhouse study, I assessed the efficacy of glyphosate and four graminicides
(clethodim, sethoxydim, fluazifop, and quizalofop) applied at two rates, to cheatgrass plants of different heights. I also assessed the same five herbicides on three accessions of cheatgrass and Japanese brome. My field study targeted the same two annual bromes on two coal mines along the Montana, Wyoming boarder. Four herbicide treatments (control, glyphosate, quizalofop, or both) and two seeding treatments were evaluated for their effectiveness to manage annual bromes and boost seeded species establishment. Half of each herbicide plot was retreated with quizalofop the second year.
Results suggest that targeted herbicide applications can be used to control non-native annual bromes and increase seeded species establishment. Specifically, using glyphosate pre-seeding when plants are small and graminicides post-seeding, can decrease annual brome cover. These treatments can provide a window of opportunity for establishing species from seed, including Wyoming big sagebrush.
- Department of Land Resources and Environmental Sciences