• Leaf Water Potentials of Perennial Grasses—Leaf Press and Pressure Chamber Evaluation

      Cox, J. R.; Hughes, H. G. (Society for Range Management, 1982-01-01)
      The leaf water potentials of blue grama [Bouteloua gracilis (H.B.K.) Griffiths] and western wheatgrass (Agropyron smithii Rydb.) transplants were measured using a pressure chamber and a leaf press. Combined water potentials for both species ranged from -5.34 to -26.05 bars for the pressure chamber and -5.52 to -16.24 bars for the leaf press. Trends between the to methods were more consistent for blue grama. Generally, large increases in leaf water potential measured with the pressure chamber were measured as small changes with the leaf press.
    • Long-Term Effects of Fertilization and Subclover Seeding on Northern California Annual Range

      Vaughn, C. E.; Murphy, A. H. (Society for Range Management, 1982-01-01)
      The long-term effects of P and S fertilizers and subclover seeding on northern California annual range production and composition were measured during a 20-year study. Following an initial calibration period, two pastures were seeded and fertilized; pasture A prior to the 1968 growing season and pasture B prior to the 1973 growing season. After treatment pasture A produced significantly more forage annually. It also produced significantly more winter forage, and winter and annual forage N than either of two adjacent untreated control pastures during the period from 1973 to 1979. This was due primarily to an increase in native legumes because subclover averaged only 7% of cover. Treatment on pasture B gave similar responses, but the relative increases in forage production were larger (annual production increased about 2,000 kg/ha compared to 1,200 kg/ha on pasture A), and winter forage N concentrations were significantly higher than on pasture A. This was due to the greater subclover component (36%) on pasture B. The significant increases in forage production and protein indicate that subclover seeding and appropriate fertilization are practical ways of improving utilization of northern California annual range.
    • Monoterpenoid Content of Pygmy Rabbit Stomach Ingesta

      White, S. M.; Welch, B. L.; Flinders, J. T. (Society for Range Management, 1982-01-01)
      During mid-January 1979, ingesta samples were collected from the stomachs of ten wild pygmy rabbits. The ingesta samples were analyzed for big sagebrush and monoterpenoid content. Big sagebrush comprised 97% of the material in the ingesta and was the only forage containing monoterpenoids. Monoterpenoid content of the ingesta was only 23% of expected levels. This major loss (77%) of monoterpenoids may occur during mastication. Loss of monoterpenoids from mastication by pygmy rabbits was measured in an airtight rabbit chamber. Twelve times more monoterpenoids were recovered during the rabbit feeding trials (big sagebrush and rabbit) than during the control tests (big sagebrush only).
    • Nitro Compounds in Introduced Astragalus Species

      Williams, M. C.; Davis, A. M. (Society for Range Management, 1982-01-01)
      Leaves of foreign Astragalus species were examined for the presence and type of poisonous aliphatic nitro compounds. Twenty-two (24%) of the 92 species examined tested positive for nitro compounds and 70 (76%) tested negative. Three nitro-bearing species, Astragalus bodeanus Fisch., Astragalus isfahanicus Boiss., and Astragalus siliquosus Boiss. synthesized 3-nitro-1-propanol (3-NPOH). The other nitro-bearing species synthesized 3-nitropropionic acid (3-NPA). Ten taxonomic sections had a high percentage of nitro-bearing species. Chemotaxonomic relationships in Astragalus suggest that most, if not all, of the other species in these 10 sections would synthesize nitro compounds.
    • Preliminary Study of Some Insects Associated with Rangeland Shrubs with Emphasis on Kochia prostrata

      Moore, T. Blaine; Stevens, Richards; McArthur, E. Durant (Society for Range Management, 1982-01-01)
      The introduced and potentially useful range shrub Kochia prostrata (prostrate kochia) and its naturalized herbaceous congener K. scoparia (annual kochia) both appear to be excellent hosts for the lygus bug (Lygus desertinus). However, lygus bugs were abundant only on concentrated Kochia stands and not on K. prostrata growing intermixed with other plant species. Therefore, it is recommended that prostrate kochia be planted in mixtures with other plant species in range rehabilitation projects so that high insect populations are not encouraged. Lygus bugs spend much of the summer on both Kochia species but move to associated plants when the associates flower. Although lygus bugs were found in abundance on prostrate kochia, no major damage to the plant was evident. Prostrate kochia apparently is not the overwintering egg host-plant for lygus bugs. On prostrate kochia, seven other identified insect species (six families) as well as several unidentified taxa were also collected. These additional species were mostly short-time residents in low numbers. Flea beetles (Psylloides punctulata) were occasionally abundant.
    • Prescribed Burning during Winter for Maintenance of Buffelgrass

      Hamilton, W. T.; Scifres, C. J. (Society for Range Management, 1982-01-01)
      Neither a single burn during late winter nor a second burn 2 years later reduced the density of mixed brush dominated by blackbrush acacia, honey mesquite, and twisted acacia which had invaded buffelgrass seedings on the South Texas Plains. Based on canopy cover and height, most woody species had recovered to preburn status after two growing seasons. Buffelgrass responded by a flush of spring growth during the year of burning and cumulative herbage production exceeded that of unburned areas for three growing seasons after the single burn. However, during dry growing conditions, less buffelgrass herbage was produced on burned than on unburned areas. A second burn tended to increase buffelgrass herbage production compared to the single burn. However, when moisture became limiting, less herbage was also produced on the twice-burned areas. Disappearance of buffelgrass, attributed primarily to grazing, closely paralleled herbage production, with the greatest disappearance occurring the first growing season after the burn.
    • Rangeland Management and the Environment

      Baumer, M. (Society for Range Management, 1982-01-01)
      Management of the rangelands of the world for multiple use is a complicated process. Rangeland productivity can be increased by several means. However, some of these means have undesirable ecological consequences. There is a need for integration of range ecosystems management on a world-wide scale under an ecological framework.
    • Reseeding by Eight Alfalfa Populations in a Semiarid Pasture

      Rumbaugh, M. D. (Society for Range Management, 1982-01-01)
      Eight alfalfa populations were seeded in a dryland pasture in northern Utah. Densities of mature plants, seeds, seedlings, and 1-year-old plants were measured in each of 3 years. The populations did not differ for mature plant stands or seed production. There was a higher rate of seedling survival for populations that primarily originated from Medicago sativa rather than M. falcata. All populations had some one-year-old plants persisting to replace mature plants killed by disease or rodents.
    • Response of Chihuahuan Desert Mountain Shrub Vegetation to Burning

      Ahlstrand, G. M. (Society for Range Management, 1982-01-01)
      The effects of fire on vegetation in the desert mountain shrub community were studied on 3 to 7-year-old burned sites near the northern limits of the Chihuahuan Desert. Coverage and frequency of redberry juniper (Juniperus pinchotii) and frequency of whiteball acacia (Acacia texensis) were lower, while frequencies of catclaw mimosa (Mimosa biuncifera) and skeleton goldeneye (Viguiera stenoloba) were higher on burned sites when compared with unburned paired plants. Lechuguilla (Agave lecheguilla), sotol (Dasylirion leiophyllum), and sacahuista (Nolina spp.) suffered losses in excess of 50% on burned sites. With the exceptions of sideoats grama (Bouteloua curtipendula) and bull muhly (Muhlenbergia emersleyi), all grasses had recovered or showed increases by the end of three growing seasons. All grasses had recovered or increased on 6 to 7-year-old burns. Recovery of burned plants was predominately by vegetative means, suggesting that periodic fires can be used to maintain or even increase grass coverage at the expense of shrubs in this community.
    • Response of Small Mammals to Livestock Grazing in Southcentral Idaho

      Johnson, M. K. (Society for Range Management, 1982-01-01)
      The effects of livestock grazing on populations of wildlife have been addressed in two recent studies on the INEL Site. However, studies were performed by measuring indices of abundance among areas where different practices had occurred prior to initiation of study. There is no proof that differences detected among the areas actually resulted from the land use practices. Studies should be conducted with replication and strict controls before correlated data can be accepted as indicators of cause and effect relationships. The large variation in the occurrence and densities of small mammals among areas with the same or similar uses suggests the need for further studies to resolve conflicting conclusions.
    • Seasonal Diurnal Variation in Composition of Cow Diets

      Kirby, D. R.; Stuth, J. W. (Society for Range Management, 1982-01-01)
      Seasonal diets between fall 1977 and spring 1979 were collected in morning and evening from esophageally fistulated cows in the Post Oak Savannah of east-central Texas. Chemical content of diurnal diets were similar within a season except CP was higher in evening collections as compared to morning collections during fall. Cows appeared to select for energy (IVDOM) over CP. Botanical composition of morning and evening diets differed only during summer. Since the cows spent more time during hot summer afternoons in the shade of woody plants, less grass and more forbs, vines, and woody vegetation were selected. Research based on morning diet collections only might result in biased samples. Recognition of nutritional and environmental stresses with potential to alter grazing behavior of animals is critical for accurate sampling of livestock diets.
    • Summer Grazing of Sagebrush-Grass Range by Sheep

      Harniss, R. O.; Wright, H. A. (Society for Range Management, 1982-01-01)
      Sagebrush-grass range normally grazed in the spring and fall can be grazed in the summer to provide a maintenance ration for ewes if their lambs are weaned early. Moderate grazing (57-99 sheep days/ha) in early or late summer did not change vegetative composition or yields. Heavy grazing (185-198 sheep days/ha) in the early summer decreased yields of grasses and the cushion-forb Hoods phlox. Late summer grazing did not change the grass or forb yields. Sagebrush yields increased in the sagebrush subtype where balsamroot was abundant under early summer grazing.
    • The Occurrence of Anagyrine in a Collection of Western American Lupines

      Davis, A. M. (Society for Range Management, 1982-01-01)
      The alkaloid anagyrine found in some Lupinus species has been shown to cause the teratogenic condition known as "crooked calf disease." A collection of western American lupines held by the Western Regional Plant Introduction Station was grown at Pullman, Washington, to determine the extent and levels of anagyrine in these accessions. The plants were field grown on Tucannon soil, a fine-silty, mixed, mesic pachic Haploxerolls. Anagyrine determinations were made by gas/liquid chromatography. Accessions that were positive for anagyrine in June 1977 were resampled and verified in 1978. Anagyrine and total alkaloids were higher in April and markedly diminished by July. Seeds were higher in total alkaloids and anagyrine, when present, than was mature vegetation.
    • The Persistence of Fenitrothion Insecticide In Red Maple (Acer rubrum L.) and White Birch (Betula papyfifera (Marsh.)) Deer Browse

      Lapierre, L. E. (Society for Range Management, 1982-01-01)
      From May 15 to November 15, 1977, vegetation plots were monitered on a constant basis in order to obtain the concentration of fenitrothion in red maple and white birch deer browse. The data obtained indicates that the concentrations tend to be as high as 21.413 ppm for the red maple and 19.371 ppm for the white birch immediately following the spray application. However, the concentrations are below 0.010 ppm 120 days following the application. Fenitroxon was detected in two of the samples taken from the sprayed plots. None was detected within the control plots. There is no evidence in the literature that a concentration of fenitrothion of the magnitude detected would have obvious effects on deer populations during their winter yarding.
    • Vegetative and Reproductive Growth of Bluebunch Wheatgrass in Interior British Columbia

      Quinton, D. A.; McLean, A.; Stout, D. G. (Society for Range Management, 1982-01-01)
      Vegetative and reproductive growth of bluebunch wheatgrass in interior British Columbia has been documented for a 3-year period. Plants began growing immediately after snow melt in the spring, with measurable growth occurring where soils had warmed to 6 +/- 0.5 degrees C at 10-cm depths. Growth ceased from 7 May to 15 July and plants fully matured from 7 July to 10 August with actual dates for each particular site being dependent upon the local microclimate. Fall regrowth was not predictable, occurring only during 1973. Seed production was erratic, unpredictable from our data, and not of sufficient magnitude to sustain the grass population if improper grazing is allowed.