Three experiments were set up to test the effectiveness of combining herbicides and perennial grass competition to control downy brome. The first two experiments tested three successive applications of glyphosate and paraquat were applied near Kaycee and Lusk to determine if the seed bank of downy brome could be reduced and if perennial grasses present in the rangeland understory could be competitively dominant. For 3 successive years paraquat was applied at four rates, glyphosate was applied at three rates and at two growth stages (two- to eight-leaf stage and the bloom stage). Both sites were intensely grazed by cattle 30 days after herbicide application for 90 days at Kaycee, and 80 days at Lusk. The first year of the study cattle were not grazed on the treatment plots. Canopy cover measurements to taken at each site. The third experiment at Riverside examined the ability of perennial grasses to establish and effectively compete with downy brome was tested at a site that was farmed but was not reseeded therefore, missing a perennial understory. Downy brome and musk thistle (Carduus nutans l.) dominated the site. Five cool-season perennial grasses (Critana thick-spike wheatgrass; Bozoisky Russian wildrye; Sodar streambank wheatgrass; Luna pubescent wheatgrass, and Hycrest crested wheatgrass) were seeded in the beginning of May. All species were seeded at a rate of 11 kg/ha with the exception of Russian wildrye, which was seed at 6 kg/ha. Each site was clipped and forage was sorted by species for annual production measurements.
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