Now showing items 21-23 of 23

    • Effect of 2,4-D on Composition and Production of an Alpine Plant Community in Wyoming,

      Thilenius, J. F.; Smith, D. R.; Brown, G. R. (Society for Range Management, 1974-03-01)
      Use of 2,4-D in an alpine plant community in the Medicine Bow Mountains of Wyoming almost completely eliminated Geum rossii. The graminoid: forb ratio of the vegetation was altered from approximately 3:7 to 8:2 without appreciably changing total standing crop or its digestible dry matter content. Resurgence of forbs could not be detected up to 4 years after treatment.
    • Control of Annual Grasses and Revegetation in Ponderosa Pine Woodlands

      Christensen, M. D.; Young, J. A.; Evans, R. A. (Society for Range Management, 1974-03-01)
      Application of 1.12 kg/ha of the herbicide atrazine sufficiently controlled medusahead or downy brome to permit establishment of perennial wheatgrass in ponderosa pine woodlands previously burned in wildfires. Fall application of atrazine greatly improved survival of ponderosa pine or bitterbrush seedlings transplanted to plots the following spring. Bitterbrush seedlings established naturally in areas treated with atrazine. Apparently the herbicide treatment created a desirable habitat for seed caching by rodents, along with reduction of competition from annual grasses. Higher rates of atrazine controlled most herbaceous vegetation and resulted in greater growth of ponderosa pine seedlings. Failure to establish perennial grasses resulted in reinvasion by annual grasses.
    • Abundance of Grasshoppers in Relation to Rangeland Renovation Practices

      Hewitt, G. B.; Rees, N. E. (Society for Range Management, 1974-03-01)
      This study was conducted during a 3-year period, 1969-1971, in northcentral Montana to determine the effect of the rangeland renovation practices of scalping, interseeding, contour furrowing, and spraying sagebrush with 2,4-D and the resulting vegetational changes on grasshopper (Acrididae: Orthoptera) species and abundance. Spraying for control of sagebrush with 2 lb of 2,4-D ester in 6 gal $H_{2}O/acre$ only slightly reduced grasshopper abundance during the first 3 postspray years. However, contour furrowing, scalping, and interseeding in general adversely affected the habitat of most grasshopper species, probably because of changes in the abundance of preferred food plants. The influence of parasites, predators, and pathogens on abundance appeared to be slight.