2014-10-07_PERMIT FILE - C1981018A (2)

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cheatgrass reflects its profound adaptation to this environment irrespective of past or present grazing practices. Several management techniques are used to help control annual weeds. In instances where disturbances are short term, sites are disturbed and reclaimed in a short period of time, usually within the same year. This limits the opportunity for annual weeds to propagate and increase in density by producing seed. The first year of site establishment is generally markedly improved by decreasing the competition from annual weeds. Sites typically suitable for this practice include drill sites and roads. However, many sites may still become inundated with cheatgrass as the original site and topsoil frequently contains a substantial seedbank of this weed. The prevalence of cheatgrass on the undisturbed native lands is a strong indication that further modifications to the vegetative community are necessary to help preclude this weed. Simply attempting to reestablish the prior native plant community only welcomes the reinvasion of this species. Use of introduced species is typically discouraged by the Division. However, given the circumstances and pervasiveness of the cheatgrass problem in the Western U.S. use of the more aggressive perennial introduced species is necessary to help overcome the competitiveness of the cheatgrass. Seed mixes found previously in this Section reflect this strategy. It should be noted that even the competitive perennial introduced species may not out compete the cheatgrass on some soils. Forage kochia has shown an exceptional ability to out compete cheatgrass. Interseeding this species by broadcasting seed onto a dense stand of cheatgrass has been successful at the Deserado Mine. Earlier concerns regarding the potential for this species to rapidly spread beyond the treated area has been unfounded. There are no indications that it is out competing the other perennial vegetation but rather just replacing the cheatgrass. Due to its rapid establishment it has not been placed in any of the regular seed mixes as it could potentially out compete other desirable species from the seedling stage. For the refuse areas where both topsoil and subsoil are salvaged for replacement, reverse sequencing of the soil material replacement appears to be a feasible means of limiting cheatgrass establishment. The nutrient and /or geochemical properties of the subsoil are less hospitable to the cheatgrass while still within the tolerance level for the perennial species. Limited fertilization is anticipated with this use of the subsoil. Excess nitrogen tends to trigger a response from the cheatgrass which could be detrimental to the long term success of the revegetation. Use of fertilizers should be limited. Cheatgrass, as well as other weedy annual species, has a much more pronounced response to fertilizer, primarily nitrogen, than the perennial seeded species. Fertilizer application should be limited to an as- needed basis, often waiting for stress response from the perennial seedlings prior to fertilizer application. Use of herbicides to treat annual weeds for reclamation purposes requires careful consideration. Timing and application rates are generally critical to avoid harming the desired vegetation while Minor Revision #157 (10/2013) V -69