Get reliable rangeland science

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 and fuel loads. 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 efforts. The objective of this study was to test the efficacy of herbicides; [Imazapic (Plateau), Rimsulfuron (Matrix), Sulfometuron Methyl (Landmark)] on 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. 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). 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 use of herbicides can aid in the suppression of cheatgrass.