Establishing perennial grasses reduces cheatgrass and associated fuels

Authors: Clements, Darin - Charlie; Harmon, Daniel - Dan

Submitted to: Society for Range Management
Publication Type: Abstract Only
Publication Acceptance Date: 1/5/2022
Publication Date: 2/22/2022
Citation: Clements, D.D., Harmon, D.N. 2022. Establishing perennial grasses reduces cheatgrass and associated fuels. Society for Range Management. 75:89.

Interpretive Summary:

Technical Abstract: The introduction and subsequent invasion of cheatgrass (Bromus tectorum) onto millions of acres of Great Basin rangelands has truncated succession by providing a fine-textured early maturing fuel that has increased the chance, rate, spread and season of wildfires. With each passing wildfire season more critical wildlife and grazing resources are being converted to cheatgrass dominance, therefore resource managers and land owners are facing the daunting task of reducing wildfire risks caused by associated cheatgrass fuels. Chemical weed control practices, in combination with rangeland seeding efforts, have the ability to be successful in actively suppressing and reducing cheatgrass associated fuels. Long-term control of the invasive annual grass, cheatgrass, is predicated on its biological suppression. Perennial grasses, which have been shown to effectively suppress cheatgrass and associated fuels. We tested the application of the pre-emergent herbicide, Sulfometuron Methyl @ 1.75oz/ac rates in a completely randomized block design in northern Nevada. The treated plots were fallowed for one year and then seeded to a perennial grass mix of Siberian wheatgrass (Agropyron fragilla ssp. sibiricum) at 4 lbs/ac rate, ‘Anatone’ bluebunch wheatgrass @ 4 lb/acre rate, Sherman big bluegrass @ 1 lb/acre rate and Sandberg’s bluegrass @ 1 lb/acre rate in the fall 2015 and 2016. Sulfometuron Methyl significantly reduced cheatgrass above-ground densities by 98.7%. This reduction in cheatgrass densities significantly improved the emergence and establishment of seedlings of seeded species which averaged 0.8 and 0.9/ft². Cheatgrass was significantly reduced with the establishment of perennial grasses as the control plots averaged 1,206 lbs/acre of dry weight cheatgrass fuel compared to 135 lbs/acre of dry weight cheatgrass fuel, an 89% reduction in cheatgrass fuel loads. The ability of resource managers to successfully seed perennial grasses will. significantly reduce catastrophic wildfires on arid Great Basin rangelands.