Location: Great Basin Rangelands ResearchTitle: Herbicide efficacy and perennial grass establishment
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2014
Publication Date: 1/31/2015
Citation: Clements, D.D., Harmon, D.N. 2015. Herbicide efficacy and perennial grass establishment. In: Society for Range Management Meeting Abstracts, January 31-Feb 6, 2015, Sacramento, CA. 68:395.
Technical Abstract: Cheatgrass (Bromus tectorum) invasion has astronomically altered native plant communities throughout the Intermountain West. Cheatgrass truncates secondary succession by outcompeting native plant species for limited resources, thus building persistent seed banks to take advantage of conditions that occur in arid environments. Cheatgrass increases the chance, rate, spread and season of wildfires. Rehabilitation of cheatgrass infested rangelands is a daunting task that faces land owners and resource managers annually. The establishment of long-lived perennial grasses is key to suppressing cheatgrass densities, fuel loads and to allow succession to occur. The ability of resource managers to have tools available to them to control such aggressive weeds as cheatgrass is instrumental in the success of rehabilitation and restoration efforts. The objective of this study was to test the efficacy of herbicides; [Imazapic (Plateau), Rimsulfuron (Matrix), and Sulfometuron Methyl (Landmark)] in controlling cheatgrass and allowing for the establishment of seeded species. Herbicide treatments were applied in the fall of 2011 and 2012: 1) Imazapic @ 6oz/ac, 2) Rimsulfuron @ 4oz/ac, and 3) Sulfometuron Methyl @ 1.75oz/ac rates in a completely randomized block design at two separate sites in northern Nevada (Antelope, Squaw). The treated plots were fallowed for one year and then seeded to Siberian wheatgrass (Agropyron fragilla ssp. sibiricum) at 7 lbs/ac rate (fall 2012 and 2013). Siberian wheatgrass was chosen from previous plant material testing trials. Precipitation was higher in 2011/2012, 7.4”, at the Antelope site compared to 2012/2013, 6.1”. Squaw was very dry in 2011/2012, 4.4”, but received 7.5” in 2012/2013. The Squaw study site reported the best results in the 2012/2013 plots with Sulfometuron Methyl yielding the highest control of cheatgrass above-ground densities from 24.7/ft² down to 0.4/ft² (98.7%) followed by Imazapic, 17.6/ft² down to 0.8/ft² (95.6%) and Rimsulfuron 13.1/ft² down to 1.1/ft² (91.9%). The control plots averaged 39.3 cheatgrass plants/ft². Siberian wheatgrass seedling densities in the Sulfometuron Methyl treated plots yielded 6.5/ft², followed by Imazapic, 4.1/ft² and Rimsulfuron, 1.5/ft². Control plots did not establish any perennial grasses in them. The use of herbicides can aid in the suppression of cheatgrass.