• Brush Control with Herbicides on Hill Pasture Sites in Southern Oregon

      Norris, L. A.; Montgomery, M. L.; Warren, L. E.; Mosher, W. D. (Society for Range Management, 1982-01-01)
      Silvex alone or with 2,4-D in a 1:1 ratio at about 3 to 4 kg/ha gave 60 to 100% control of many brush species including poison oak, Oregon oak, and maples. Picloram at 1 kg/ha plus 2,4-D at 4 kg/ha was most effective with respect to the amount of picloram; however, the mixture of 1 kg/ha plus 2 kg/ha respectively, was nearly as good. Complete pasture renovation in this area requires brush control, burning, fertilization, and seeding of desirable species. Picloram and 2,4-D disappear from soils in 29 months with no significant leaching into the soil profile at these study sites. Herbicide discharge in streamflow was small, representing 0.35% and 0.014% of applied picloram and 2,4-D. We believe that nearly all of the herbicide discharged from these watersheds represents residue deposited in dry stream channels or that mobilized by fall rains from adjacent streambanks. Significant overland movement of herbicides from upslope did not occur on these study areas. The probability of crop damage from irrigation with water from these watersheds is low.
    • Cattle Diets in the Blue Mountains of Oregon, I. Grasslands

      Holechek, J. L.; Vavra, M.; Skovlin, J.; Krueger, W. C. (Society for Range Management, 1982-01-01)
      Esophageally fistulated cows were used to determine cattle diets on grassland range in northeastern Oregon in 1976, 1977, and 1978. Idaho fescue, bluebunch wheatgrass, and Sandberg bluegrass were the most common species in the diets. Forb consumption declined while grass consumption increased with seasonal advance from late spring to fall. Food habits depended largely on phenological development of forage species. Forbs were preferred over grasses early in the grazing season; then after forbs reached maturity, cattle were selective for the plants that remained green. Diet similarities were compared between periods within years, and between years within periods. When diets were pooled into late spring, early summer, late summer and fall groups, late spring diets were least similar to the others. Diet variation from year to year was also less later in the grazing season. Utilization of Idaho fescue and bluebunch wheatgrass should be considered in grazing management decisions on grasslands in the Blue Mountains.
    • Cattle Grazing Influence on a Mountain Riparian Zone

      Roath, L. R.; Krueger, W. C. (Society for Range Management, 1982-01-01)
      A combination of management and physical topographic constraints caused cattle to concentrate on the riparian zone early in the grazing season in 1977 and 1978. A large percentage of cattle days and vegetation utilization on the riparian zone occurred in the first 4 weeks of the grazing period. Utilization on herbaceous vegetation was 76 and 72% in 1977 and 1978, respectively. Impact of grazing on the most prevalent species, Kentucky bluegrass was minimal. Shrub use increased with increased maturity of herbaceous vegetation. Utilization of major shrubs was not excessive in either year, and very likely had no long-term effects on either the abundance or vigor of the shrubs.