Get reliable rangeland science

As part of the process of energy extraction, soils are scraped from sites to access mineral deposits or to create level surfaces for drilling or mining activities. This disturbance kills plants, and makes it necessary to reintroduce desirable species once extraction activities are completed. Reclamation after disturbance of soils and vegetation associated with energy extraction is critical for ecosystem function and is required by law. Weedy annual species often dominate reclamation sites for the short-term, competing for resources with newly-seeded desirable vegetation. Our objectives were to: 1) evaluate herbicide effects on weedy and desirable species, 2) determine the effect of treatment timing (herbicide and seeding) on reclamation success, and 3) evaluate the performance of different species and seed mixes. Fifteen herbicide treatments and ten seed mixes were applied in a split-plot design to three sites in Wyoming to evaluate effectiveness of different reclamation practices. Most herbicide treatments targeted broadleaved weeds with the substitution of two treatments targeting annual grasses at one site. Seeding treatments were applied at two timings (fall, spring) across herbicide treatments to investigate establishment rates of specific species under different seeding times. Second-year data on weed control and seeded species establishment from cover and percent stand observations from mid-summer 2013 are presented. Herbicides, specifically those including aminocyclopyrachlor, reduced annual weedy forb cover (p<0.05) at two sites. Undesirable annual grasses were reduced by herbicides (p<0.05) at two sites. The most effective were rimsulfuron and imazapic. Seeded species establishment remained low at two sites, however, all sites showed significant species-specific establishment (p<0.05). The best establishment occurred at a site where high annual grass competition was reduced with spring seeding. A second site had slightly better establishment from fall seeding. Seeded wheatgrass and wildrye species established best at most sites. Evaluation will continue for a third year.