Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: February 8, 2013
Publication Date: July 22, 2013
Citation: Clements, D.D., Harmon, D.N. 2013. Imazapic, rimsulfuron, and sulfometuron methyl effectiveness at controlling cheatgrass[abstract]. Soil and Water Conservation Society International Meeting, Reno, NV, July 21-24, 2013. 68:79. Technical Abstract: The introduction and subsequent invasion of cheatgrass (Bromus tectorum) onto Intermountain rangelands has resulted in increased frequencies of wildfires and severely altered native plant communities. These destructive wildfires have negatively impacted wildlife and grazing resources. 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 effectiveness of herbicides [Imazapic (Plateau), Rimsulfuron (Matrix), Sulfometuron Methyl (Landmark)] on controlling cheatgrass and allowing for the establishment of seeded species. Twelve plots, 25m x 50m, were established in fall 2010 and treated with 1) Imazapic @ 6oz/ac, 2) Rimsulfuron @ 4oz/ac, and 3) Sulfometuron Methyl @ 1.75oz/ac rates and replicated 3 times in a completely randomized block design with controls. The treated plots were fallowed for one year and then seeded to Siberian wheatgrass (Agropyron fragilla ssp. sibiricum) at 7 lbs/ac rate. Sulfometuron Methyl yielded 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 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 yielded 1.1/ft² despite only receiving 6.2” of annual precipitation. The Sulfometuron Methyl and Imazapic treated plots should result in sufficient long-lived perennial grass establishment to suppress cheatgrass densities in the near future.