Weed Management Options to Improve Reclamation of Drastically Disturbed Lands

Oil and gas well pad development processes result in drastically disturbed lands which need to be revegetated. Some reclamation practices include weed control with herbicides and reseeding with desirable species. The goal of this research was to evaluate various combinations of herbicides and desirable species for their use in reclamation projects. The objectives of the field project were: 1) evaluate the effects of treatment timing (herbicide and seeding) on reclamation success, 2) determine herbicide effects on weedy and desirable species, and 3) evaluate the performance of different species and seed mixes. Our results enforced the knowledge that reclamation success is site-specific and that first year establishment of seeded species may be limited by environmental conditions. Season of treatment application can also impact success, and it will also vary by site. Often fall seeding with later herbicide applications provided the best results. Species with the highest establishment and the lowest weed cover through time included the introduced species crested wheatgrass and Russian wildrye and native species western wheatgrass and basin wildrye. Herbicides consistently providing good weed control and limited damage to desirable species included aminocyclopyrachlor and aminocyclopyrachlor + chlorsulfuron at various rates and timings. Our objective for the greenhouse project was to evaluate direct impacts of herbicides and application timing on desirable species and weed species commonly found in reclamation projects to help provide explanations or support to the field project. Earlier herbicide application caused more damage than later applications across all species and herbicides. Responses to herbicides varied among species, as expected. Some species found to have increased sensitivity to herbicides included big bluegrass and Lewis flax. Herbicides causing the least damage included saflufenacil, chlorsulfuron, and aminocyclopyrachlor + chlorsulfuron at 76 + 28 g ai/ha, particularly with crested wheatgrass and streambank wheatgrass.