Matt A. Bahm, Wildlife and Fisheries Sciences, South Dakota State University, NPB 138, Box 2140B, Brookings, SD 57007 and Thomas G. Barnes, Department of Forestry, University of Kentucky, 214 Thomas Poe Cooper Building, Lexington, KY 40546.
Smooth Brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis) are introduced cool-season perennial grasses known to invade grasslands throughout North America. During the fall of 2005 and spring of 2006, we implemented a removal study at 6 native prairie sites in eastern South Dakota that have been invaded by smooth brome and Kentucky bluegrass. Treatments included five herbicide combinations and a fall burn to determine the potential of each for renovation of invaded native grasslands. The herbicide combinations were applied in the fall and spring to determine optimum timing for control. Across sites, control plots averaged 28% and 33% cover by smooth brome and Kentucky bluegrass, respectively. Smooth brome cover on herbicide treated plots ranged from 1 to 14% and Kentucky bluegrass cover ranged from 2 to 24%. Smooth brome cover was similar between fall burned and control plots (21% to 28%), but Kentucky bluegrass cover was significantly lower (12% to 33%). Native plant response was similar across fall treatments, but spring treatments had a more detrimental effect on both native grasses and forbs. Several herbicide combinations show potential for removal of exotic grasses, while causing minimal harm to native species.