Location: Great Basin Rangelands ResearchTitle: Cheatgrass seed bank densities following imazapic and indaziflam treatments
Submitted to: Western Society of Weed Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2021
Publication Date: 3/2/2021
Citation: Clements, D.D., Harmon, D.N., Quicke, H. 2021. Cheatgrass seed bank densities following imazapic and indaziflam treatments. Western Society of Weed Science. 74:17.
Technical Abstract: The accidental introduction invasion of cheatgrass throughout millions of hectares of Intermountain West rangelands has resulted in the conversion of formerly big sagebrush/bunchgrass communities to annual grass dominance. Resource managers need tools to conduct aggressive and effective weed control practices on cheatgrass-infested rangelands to improve restoration/rehabilitation efforts.The use of pre-emergent soil-active herbicides can be very effective in decreasing cheatgrass seed bank densities and above-ground densities that limit the establishment of perennial species. Pre-emergent soil-active herbicides, Imazapic and Indaziflam were applied in the fall of 2018 our Bedell study site in northern Nevada to test efficacy on cheatgrass control. We apply these pre-emergent herbicides in the fall of the year prior to any fall germination of cheatgrass and fallow the site for 1-year prior to seeding desirable species. Due to the continued residue of these soil-active herbicides, cheatgrass seed bank densities were measured post-seed set the second year following application. Seed bank densities in Imazapic treated plots ranged from 484 - 3,486 cheatgrass/m² averaging 1,722 cheatgrass/m². Cheatgrass seed bank densities in the Indaziflam treated plots ranged from 0 - 463 cheatgrass/m² averaging 58 cheatgrass/m². Untreated plots ranged from 1,356 - 4,164 cheatgrass/m² averaging 2,496 cheatgrass/m². It is reported that Indaziflam has the potential to control cheatgrass germination up to 4-years, therefor, there may be a residual effect of this herbicide that continues in the soil to effectively decrease cheatgrass seed bank densities past the initial 1-year fallow-seeding method, if so this residual effect may also limit seedlings of seeded species.