Some Effects of Competition from Cheatgrass Brome on Crested Wheatgrass and Bluestem Wheatgrass

Many attempts have been made to re-establish the more valuable perennial bunchgrass species by artificial reseeding on western ranges supporting dense stands of cheatgrass brome (Bromus tectorum L.) .' Some reseeding trials have been planned to give fall germination of the planted grasses, while in other trials spring germination has been secured. Most of these seeding attempts have been unsuccessful. The ability of cheatgrass brome to compete successfully with seeded species for light and soil moisture is generally considered to be a cause of these failures. To measure the effects of competition offered by cheatgrass brome on re-establishment of perennial grasses, an experiment was designed to measure its effects on the growth and development of crested wheatgrass (Agropyron cristatumn (L.) Beauv.) and bluestem wheatgrass (Agropyron smithi Rydb.). These two drought-resistant grass species are widely used to revegetate arid and semiarid range lands of the West. Cheatgrass brome, an annual grass native to Europe and introduced accidentally into the United States about fifty years ago, has become abundant in the foothill ranges during the past thirty or forty years. It has become established on