• Morphology and Growth in Seedlings of Several C4, Perennial Grasses

      Coyne, P. I.; Bradford, J. A. (Society for Range Management, 1985-11-01)
      Establishment of forage grasses depends upon their ability to compete for resources in the critical seedling establishment phase. Desirable native grass species are generally considered to be more difficult to establish from seed than the introduced Old World bluestems (Bothriochloa spp.), although comparative data are generally lacking. This study compared the responses of morphological attributes commonly associated with seedling vigor and some growth parameters in 17 perennial, C4 grasses including 5 native and 12 Old World bluestems. Plants were grown in a greenhouse under well-watered and limited watering regimes. The objective was to document differences in morphology and growth among these grasses from emergence through 7 weeks post emergence. The Bothriochloa species generally rated higher than the native species in morphological characters commonly associated with seedling vigor. The exotics produced as much or more biomass and had more leaf area per plant, more tillers, and leaves per tiller than the natives. Although the native grasses produced less leaf area, the cost of these leaves in terms of biomass per unit area was higher than in the introduced grasses. The natives tended to partition relatively more biomass aboveground and more of this to leaves, rather than sheaths plus stems, than the Old World bluestems. However, partitioning of total plant biomass among roots, sheaths plus stems, and leaf blades was remarkably insensitive to water stress in all entries. Approximately one-third of total biomass was partitioned among leaf blades, sheaths plus stems, and roots, respectively, with sheaths+stems tending to be a slightly smaller fraction than the other 2 components. Recurring water stress cycles reduced most parameters significantly and generally accentuated the normal ontogenetic decline in relative growth and unit rates. Across all entries, total plant biomass and leaf blade area were reduced over 40% by a limited watering regime. Although water stress reduced the size of the assimilatory surface, the remaining leaves were more efficient in the production of new biomass. This response correlated with an increase in specific leaf weight under water stress.
    • Plant Associations within the Interior Valleys of the Umpqua River Basin, Oregon

      Smith, W. P. (Society for Range Management, 1985-11-01)
      Eleven plant associations were identified and characterized according to the frequency, percent cover, and relative dominance of the herbaceous and woody species among the vegetative strata, including stem density, diameter breast height (dbh), and basal area for tree species: Cynosurus echinatus/Taeniatherum asperum; Bromus mollis/Cynosurus echinatus; Rhus diversiloba/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Taeniatherum asperum/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Dactylis glomerata; Pseudotsuga menziesii/Quercus garryana/Rhus diversiloba/Polystichum munitum; Quercus garryana/Arbutus menziesii/Rhus diversiloba/Cynosurus echinatus; Arbutus menziesii/Rhus diversiloba/Festuca arundinacea; Quercus garryana/Fraxinus latifolia/Rosa elganteria/Juncus effusus; Pseudotsuga menziesii/Corylus cornuta/Cynosurus echinatus. The intensity and duration of recent disturbance distinguished early seral stages which were characterized by a paucity of native shrub and herbaceous species and an abundance of annual invaders in the understory. The primary forces that influenced existing plant assemblages were fire and more recently agricultural practices, especially among grasslands and savannas. Grasslands without recent livestock use exhibited greater species diversity, supporting more species and a more homogeneous distribution of relative abundance among species.
    • Precipitation, Soils and Herbage Production on Southeast Wyoming Range Sites

      Hart, R. H.; Samuel, M. J. (Society for Range Management, 1985-11-01)
      Herbage production and precipitation were determined at 13 locations in 483 ha of mixed grass range 1975-1979; production was determined at all locations 1982-1983, but precipitation was measured only at the main weather station. Vegetation and herbage production were more uniform on sites with similar subsoil than on sites with similar surface soil, the usual basis for site classification. Within any year, herbage production on similar sites was not correlated with spatial distribution of precipitation. Across years 1975-1979 and 1982-1983, herbage production on sites with sandy subsoil was correlated with March-April weather station precipitation (r2=0.866**) and March-April plus May-August precipitation (R2=0.95**). Herbage production on sites with loamy subsoil was not significantly correlated with precipitation in March-April (r2=0.32) or any other period.
    • Recovery of Vegetative Cover and Soil Organic Matter During Revegetation of Abandoned Farmland in a Semiarid Climate

      Dormaar, J. F.; Smoliak, S. (Society for Range Management, 1985-11-01)
      Much of the farmland in the Canadian Prairie region has been abandoned over the years and allowed to revert to weedy cover and eventually to grassland. While some of the changes in vegetation during plant succession have been documented, limited information is available on changes in soil characteristics. The purpose of this study was to assess the vegetative cover and soil transformation under similar semiarid climatic conditions with an annual precipitation of about 310 mm on 3 sites abandoned in 1925, 1927, and 1950 as compared to adjacent native range. Total C and N, water-stable aggregates between 1.0 and 5.0 mm, and polysaccharide content increased, while chelating resin-extractable C, humic acid/fulvic acid ratios, caloric content of the rootmass, and dehydrogenase activity decreased in the successional sequence. Nevertheless, more than 55 years will be required to allow soil to return to native range standards under moderate grazing by livestock. Revegetated range may have to be subjected to lighter grazing pressures than usual to allow the vegetation to continue to increase its rootmass and thus the soil chemical properties. A hypothesis to explain changes in root- and top-mass ratios with time on the basis of the quality of soil nitrogen has been advanced.
    • Storage Life of Illinois Bundleflower and Western Indigo Seed

      Call, C. A. (Society for Range Management, 1985-11-01)
      Seed of Illinois bundleflower (Desmanthus illinoensis (Michs.) MacM.) and western indigo (Indigofera miniata var. leptosepala (relative humidity were imbibed in a controlled environment for 20 Turdays with a night/day temperature regime of 15/25 degrees C and a 12-hour en stored for 1 to 4 years at 16 degrees C and 40% photoperiod. Preimbibition treatments included acid scar-ification by immersion in concentrated sulfuric acid for 15 minutes, mechanical scarification by cutting the seed coat at the end opposite the micropyle, and an untreated control. Seed viability was determined by a triphenyl tetrazolium chloride test. Germination rate and cumulative germination decreased for untreated Illinois bundleflower seed and increased for untreated western indigo seed as the length of storage increased from 1 to 4 years. The decrease in germinability of Illinois bundleflower seed was related to the development of an impermeable seed coat, while the increase in germinability of western indigo seed was related to a decease in hard seededness and the fulfillment of after-ripening requirements. Scarification treatments increased cumulative germination and germination rates in each seed storage class for both species. Over the 4-year storage period, Illinois bundleflower seed viability decreased by approximately 10%, and western indigo viability remained relatively constant.
    • Technical Notes: The relationship of stocking intensity and stocking pressure to other stocking variables

      Scarnecchia, D. L. (Society for Range Management, 1985-11-01)
      Stocking intensity and stocking pressure have been defined and used as technical stocking variables describing animals on pasture. Relationships between these variables and stocking variables such as stocking density and stocking rate are discussed. One conclusion is that stocking intensity and stocking pressure are not informationally unique variables, but are equivalent to stocking variables defined in other work. Retention of the terms stocking intensity and stocking pressure is recommended for nontechnical use in describing livestock grazing.
    • The Effects of Fire on the Blackbrush (Coleogyne ramosissima) Community of Southwestern Utah

      Callison, J.; Brotherson, J. D.; Bowns, J. E. (Society for Range Management, 1985-11-01)
      Eight general study sites were examined in the blackbrush (Coleogyne ramosissima) zone of southwestern Utah in order to assess the impact of burning. All sites had been burned. Age since burning varied from 1 to 37 years. Plots were placed in burned areas with plots in adjacent unburned areas serving as controls. Sites were similar enough that definite trends were distinguishable despite between site variation. Recently burned areas were dominated by forbs, middle aged burns were dominated by grasses, and the oldest burns had reverted back to shrub dominance. Cryptogamic soils crusts were severely affected by burning and showed no signs of recovery after 19.5 years. Blackbrush was also severely affected and showed no signs of recovery after 37 years. Lack of recovery by blackbrush may be due to its paleoendemic nature. Future burning of stands of blackbrush in southwestern Utah is not recommended.
    • The Role of Fourwing Saltbush in Mined Land Reclamation: A Viewpoint

      Booth, D. T. (Society for Range Management, 1985-11-01)
      Ease of establishment by direct seeding has resulted in fourwing saltbush [Atriplex canescens (Pursh) Nutt.] becoming the principal, sometimes the only, shrub on certain revegetated mined lands in Wyoming. To prevent dense stands that might exclude other shrub species, the Wyoming Department of Environmental Quality-Land Quality Division, now limits the amount of fourwing saltbush that can be included in a reclamation seed mix. There is evidence that fourwing saltbush may aid, rather than hinder, the establishment of other shrubs. A thesis is developed for fourwing's role as a pioneer species that creates ecosystem diversity, auguments the invasion of late-succession plants, and declines in density as succession progresses. The shrub is recommended as a means to direct succession toward successful reclamation. Mine managers are cautioned that the rate of natural invasion of climax species into seeded stands of fourwing saltbush is not known.
    • Variation and Names in the Poa secunda Complex

      Kellogg, E. A. (Society for Range Management, 1985-11-01)
      The members of the Poa secunda complex were studied using transplant experiments, morphological studies of population samples, and various numerical taxonomic techniques including principal components analysis and discriminant analysis. The complex is shown to comprise 2 species: Poa curtifolia, a serpentine endemic from central Washington, and P. secunda, a widespread polymorphic rangegrass. Other forms may be recognizable locally, but do not represent separate evolutionary lines. If range managers need names for these local forms, the names should be informal English names rather than Latin binomials.
    • Viewpoints: Observations on Why Mongrels May Make Effective Livestock Protecting Dogs

      Coppinger, R. P.; Smith, C. K.; Miller, L. (Society for Range Management, 1985-11-01)