Submitted to: Oregon State University Extension Publications
Publication Type: Government publication
Publication Acceptance Date: 12/10/2011
Publication Date: 12/20/2011
Citation: Johnson, D.D., Davies, K.W. 2011. Revegetating sagebrush rangelands invaded by medusahead. Oregon Beef Council Report. Oregon State University Extension Publications. p.62-64. Interpretive Summary: Medusahead is an exotic annual grass invading rangelands and decreasing livestock forage production, degrading wildlife habitat, and reducing biodiversity. Effective treatments to control medusahead are needed to create opportunities to establish more desirable vegetation. We evaluated prescribed fall burning followed by an application of imazapic, a pre-emergent herbicide, as a treatment for controlling medusahead. Preliminary results suggest that this treatment successfully controls medusahead. Land managers can use this information to help select treatments to manage medusahead.
Technical Abstract: The objectives of this study are to determine: 1) effective treatments for controlling medusahead and 2) the appropriate plant materials for revegetating medusahead-invaded rangelands. Initial treatments of prescribed burning immediately followed with applications of the preemergent herbicide imazapic were applied to three 130 x 165 ft plots at each of five sites in eastern Oregon during the fall of 2010. The same treatment combination was applied to an additional 130 x 165 ft plot at each of the five sites during the fall of 2011. All burned and herbicide treated plots were seeded during the fall of 2011 with either a mix of introduced species, native species, or a combination of introduced and native species. The study also includes an untreated control plot at each of the five sites. Prescribed burning followed with an application of imazapic at a rate of 6 oz/ac substantially reduced medusahead cover and density compared to the untreated controls. Initial results suggest fall prescribed burning to remove persistent medusahead litter followed immediately with applications of imazapic at a rate of 6 oz/ac is an effective treatment combination for controlling medusahead. Revegetation success of seeded introduced and native plant materials will be reported in subsequent progress reports and a final report.