Weed Control-Revegetation Systems for Big Sagebrush-Downy Brome Rangelands

Abstract

Chemical weed control systems integrating 2,4-D or picloram spraying for brush control and atrazine fallow for downy brome control were investigated in a series of rangeland communities. Application of both weed control techniques greatly enhanced seedling growth and increased yield of perennial grasses seeded the year after the fallow. Added nitrogen either had negligible effects or tended to negate the benefits of the weed control systems on establishment of perennial grasses. The 2,4-D/atrazine-fallow system also allowed establishment of the browse species, cliffrose, in a big sagebrush/downy brome community. Increased soil moisture available during the growing period of the fallow and seedling years, because of decreased weed competition, was the major factor for the better stands of grass and browse that resulted from chemical weed control systems.