• Natural Establishment of Aspen from Seed on a Phosphate Mine Dump

      Williams, B. D.; Johnston, R. S. (Society for Range Management, 1984-11-01)
      The natural reproduction of aspen (Populus tremuloides Michx.) from seed was discovered on a phosphate mine dump in southeastern Idaho. Aspen seedlings were found growing on areas that were essentially bare except for scattered plantings of containerized shrubs and trees. Aspen survival and growth was monitored for 4 growing seasons. Seedling density varied from 2 to 10 per m2, seedling heights varied from 16 to 81 cm, and survival rate was 73% at the end of 4 growing seasons. No changes in the number of seedlings were noted after the second growing season.
    • Variability of Infiltration within Large Runoff Plots on Rangelands

      Devaurs, M.; Gifford, G. F. (Society for Range Management, 1984-11-01)
      In this study we investigated the variability of infiltration on native rangeland sites. A rainfall simulator was used to collect data on runoff from small (0.37 m2) plots located within large plot boundaries (32.5 m2). Three range sites were sampled and data were collected from unfenced, fenced, and rototilled conditions on each site. In addition data were collected on vegetation, antecedent moisture, bulk density, soil texture, and organic matter as possible explanations for variations in hydrologic response on small and large plots. The field study demonstrated large variability in measured infiltration and soil physical properties on relatively uniform rangeland sites, suggesting that inherent variability patterns need to be examined to provide appropriate confidence intervals for single parameter values that may be applied to larger areas. No set of factors consistently explained the observed variability within large plots.