• Influence of Vesicular-Arbuscular Mycorrhizal Fungi on the Nodulation and Growth of Subclover

      Green, N. E.; Smith, M. D.; Beavis, W. D.; Aldon, E. F. (Society for Range Management, 1983-09-01)
      This study was initiated to determine the influence of vesiculararbuscular mycorrhizal (VAM) fungi on a rhizobium-legume interaction. Inoculation of subclover with Glomus fasciculatus resulted in 2 times as many rhizobium nodules on roots as on nonmycorrhizal controls. Inoculation with Glomus mosseae resulted in 1.4 times greater nodule formation compared to the noninoculated controls. Plants inoculated with G. mosseae + G. fasciculatus had 1.9 times more nodules than the controls. Furthermore, inoculation with G. fasciculatus or G. mosseae + G. fasciculatus resulted in shoot weights and total plant weights nearly double that of the controls. The conclusion is that inoculation with the correct VAM fungal species is as important as the selection of the rhizobium species for subclover growth and development.
    • Feral Herbivores Suppress Mamane and Other Browse Species on Mauna Kea, Hawaii

      Scowcroft, P. G.; Giffin, J. G. (Society for Range Management, 1983-09-01)
      Abundance, survival, and growth of mamane (Sophora chrysophylla) regeneration were determined inside and outside sheep exclosures located in heavily browsed portions of the mamane forest of Mauna Kea, Hawaii. Vegetational cover of other species was estimated. Mamane grew abundantly inside 16-year-old exclosures but was sparse outside. Height class distributions indicated that feral sheep prevented establishment of regeneration. Survival of seedlings and sprouts at 2-year-old exclosures was greater inside than outside. The largest difference between survival inside and outside was found where browsing pressure was greatest. Mamane reproduction exposed to browsing tended to be shorter than protected reproduction. Rate of height growth for protected mamane reproduction was significantly affected by exclosure location. Cover data for preferred browse species other than mamane indicated that 3 endemic grasses-Hawaiian bent (Agrostis sandwicense), he'u-pueo (Trisetum glomeratum), and Deschampsia australis, an endemic shrub-aheahea (Chenopodium oahuense), and an introduced forb-gosmore (Hypochoeris radicata)-were susceptible to browsing. On the basis of these findings, vegetation recovery should be rapid in most areas where feral sheep are eliminated or reduced.
    • Biases in the Step-Point Method on Bunchgrass Ranges

      Strauss, D.; Neal, D. L. (Society for Range Management, 1983-09-01)
      During a study of grazing in the Great Basin, using the grazed plant method used for measuring utilization, we noticed a bias in the step point technique used to select plants. Subsequent mathematical calculations showed both the direction and order of magnitude of the bias: the step point method overestimates the number of large plants and underestimates the number of small plants; when used to estimate the basal area of bunchgrasses the method overestimates the area of small plants. The calculations were tested and verified on maps of real and artificial bunchgrass populations. When the plants are distributed at random, the biases can be removed. For estimation of numbers, one should select the plant whose center (rather than perimeter) is closest to the toe point to eliminate bias by size class; for estimations of basal area, the numbers in each size class should be scaled by the area of plants of that class.
    • Browsed-class Method of Estimating Shrub Utilization

      Schmutz, E. M. (Society for Range Management, 1983-09-01)
      The browsed-class method has been developed to measure shrub utilization based on total weight of the plant. It uses growth form to place grazed shrubs into 6 browsed-classes. The method is fast, statistically sound, relatively free from personal bias, easy to learn and use, and can be used in research or land management. In a 10-year case study to determine proper use of hairy mountain-mahogany, plants were clipped initially and then reclipped once each year in the fall or winter over a 7-year period at 0, 10, 30, 50, 70 and 90% levels based on total weight of the plant. This was followed by a 2-year recovery study. Parameters studied were numbers, length, and production of twigs; area of live and dead crown cover; and general vigor and seed production. All criteria, except area of live crown cover, indicated that 50% of total weight was proper use of hairy mountain-mahogany.
    • Burning in a Bunchgrass/Sagebrush Community: The Southern Interior Of B.C. and Northwestern U.S. Compared

      Johnson, A. H.; Strang, R. M. (Society for Range Management, 1983-09-01)
      Investigations following a wildfire near Kamloops, B.C., indicated that, contrary to reported experiences in the United States, gray rabbitbrush (Chrysothamnus nauseosus) is susceptible to fire in this area. Hence caution is necessary when developing burning prescriptions and using extrapolated information.
    • Clipping Frequency and Fertilization Influence Herbage Yields and Crude Protein Content of 4 Grasses in South Texas

      Mutz, J. L.; Drawe, D. L. (Society for Range Management, 1983-09-01)
      Crude protein content of herbage produced by buffelgrass, blue panicgrass, and Bell rhodesgrass was improved with nitrogen and phosphorus fertilization and clipping every 4 or 8 weeks, compared to harvests only at the end of the growing season. Within a fertilization level, the 8-week clipping frequency generally increased dry matter production of the grasses over the 4-week clipping frequency or the end-of-season single harvest. Kleberg bluestem herbage generally contained less protein at all phenological stages than that of buffelgrass, blue panicgrass, or Bell rhodesgrass, and dry matter production was not increased by fertilization. Crude protein content of Kleberg bluestem herbage was only slightly increased with the highest level of fertilization, regardless of clipping frequency.
    • Ecophysiology of Seed Germination and Flowering in Common Broomweed, Amphiachyris dracunculoides (DC) Nutt

      Baskin, J. M.; Baskin, C. C. (Society for Range Management, 1983-09-01)
      Common broomweed (Amphiachyris dracunculoides (DC.) Nutt.) behaves both as a winter and as a summer annual. Seeds germinate in either autumn or spring, and the life cycle is completed the following autumn. Seeds were nondormant at maturity, and 48 to 94% of them germinated in light at daily thermoperiods of 15/6, 20/10, 25/15, 30/15 and 35/20 degrees C, but 42% or less germinated in darkness at these temperatures. Thus, a high percentage of the seeds dispersed in early autumn germinate within a few days in warm soil if soil water is not limiting. With late autumn dispersal, however, germination of a high percentage of the seeds is delayed until spring. Vernalization was not required for flowering, and both vernalized and nonvernalized plants flowered under long and short photoperiods. However, plants from vernalized seeds required fewer days to flower under both photoperiods than did plants from nonvernalized controls. Additionally, plants vernalized in the seed and/or seedling stages did not form a rosette prior to shoot elongation, whereas plants not vernalized in the seed or seedling stages formed a rosette.
    • Ecotypic Variation in Tripsacum dactyloides Evaluated in Texas

      Schliesing, T. G.; Dahl, B. E. (Society for Range Management, 1983-09-01)
      Eastern gamagrass collections (26) from throughout Texas, except the Trans-Pecos, and from southern Oklahoma (3) were evaluated in a common garden at Uvalde, Texas, to select an ecotype suitable for planting in central and south Texas. Four potential ecotypes existed among the collections with a fifth existing in collections from extreme southeast Texas. The characters of this latter type overlapped those of collections from north Texas making it less distinct from the others. Collections (Type C) from central and west Texas were superior to all others in forage production, crude protein, and chlorophyll content. Collections from near Baird and Bracketville were outstanding and further field evaluation is warranted.
    • Viewpoint: Soil Boron Guidelines for Reclaimed Western Soils

      Becic, J. N. (Society for Range Management, 1983-09-01)
      Regulatory guidelines establish maximum allowable boron concentrations for mine reclamation soils and overburden. However, these toxic levels are based upon research performed on boron-sensitive crop species and not native plants that are naturally adapted to harsh conditions. Modifications of boron guideline parameters and laboratory analyses procedures as well as consideration of other soil interactions are suggested. A need for pertinent boron reclamation research is demonstrated.
    • The Use of Regression Models to Predict Spatial Patterns of Cattle Behavior

      Senft, R. L.; Rittenhouse, L. R.; Woodmansee, R. G. (Society for Range Management, 1983-09-01)
      Predictive models of cattle behavior were developed by applying multiple regression analysis to a body of behavior observations. Seven independent variables were required to describe the spatial patterns of three modes of behavior on an annual basis. Coefficients of determination were 0.50, 0.34, 0.25, and 0.20 for grazing + travel, summer resting, winter resting, and bedding, respectively. Spatial patterns of each mode were predicted for a 125-ha pasture, upon which a separate set of behavior observations had been made. Comparisons of observed and predicted patterns varied from a close fit for grazing to marginal for resting. Validation using the spatial pattern of fecal deposition, however, yielded a close fit. It was concluded that multiple regression models can be useful in predicting spatial patterns of livestock behavior and may have unexploited potential as both management and research tools.
    • The Effects of Prescribed Burning on Silver Sagebrush

      White, R. S.; Currie, P. O. (Society for Range Management, 1983-09-01)
      Prescribed burning was conducted in the spring and fall on mixed grass prairie vegetation to evaluate the effects of fire on silver sagebrush. Climatic conditions and fuel loads at the time of burning were similar in both seasons. Spring burning under good soil moisture conditions resulted in low mortality of sagebrush and vigorous sprouting. Fall burning under dry conditions resulted in greater mortality and reduced shrub regrowth. Fire intensity in both spring and fall was directly related to mortality and inversely related to subsequent growth. As intensity increased, mortality became greater and regrowth became less. This range in response to fire indicates that burning can be used advantageously to manage plant communities containing silver sagebrush.
    • The Feasibility of Microwave Ovens for Drying Plant Samples

      Smith, M. C. (Society for Range Management, 1983-09-01)
      Microwave ovens appear to be a viable alternative to forced air laboratory ovens for obtaining dry weights for vegetation samples. Two grass species, Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea), were used to determine percent moisture loss by weight at 3 weight loadings. The loadings were at approximately 50, 100, and 200 weights. For the 3 loadings, times required to obtain a dried sample were at most 4.5, 7.5, and 11.0 minutes, respectively. The time required for all samples in the conventional lab oven was 72 hours.
    • Spring Livestock Grazing Affects Crested Wheatgrass Regrowth and Winter Use by Mule Deer

      Austin, D. D.; Urness, P. J.; Fierro, L. C. (Society for Range Management, 1983-09-01)
      Areas grazed and ungrazed by cattle in spring were compared for regrowth of crested wheatgrass on a big sagebrush-grass range. Overwinter utilization of crested wheatgrass by tame mule deer and their grazing area preferences were assessed under 3 snow cover conditions-snow free, partial, and complete. Results showed regrowth production was usually higher on areas previously ungrazed by livestock. Overwinter utilization of created wheatgrass by deer was determined to be greater on ungrazed areas in both percentage of available grass used and weight per unit area consumed. Thus, interference from cured growth limiting green grass availability was more than compensated by increased production. The percentage of grass in the diet was generally higher on areas ungrazed by cattle, and deer preferred these areas under snow free and partial snow cover conditions; no preference was exhibited during complete snow cover. Recommendations for livestock grazing of seeded, foothill ranges where deer use is critical are discussed.
    • Soil Bulk Density as Influenced by Grazing Intensity and Soil Type on a Shortgrass Prairie Site

      Van Haveren, B. P. (Society for Range Management, 1983-09-01)
      Soil bulk densities were measured on 2 soil groups under 3 grazing intensities on shortgrass prairie in northeastern Colorado. On coarse-textured soils, soil bulk density means of the 3 grazing treatments were not significantly different. On fine-textured soils, average bulk density in the heavily grazed pasture was 13.4% and 11.8% higher than the lightly grazed and moderately grazed pastures, respectively. For both soil groups combined, bulk density on the heavily grazed pasture was only 6% higher than on the lightly grazed pasture. A significant grazing intensity × soil texture interaction was present, indicating that soil compaction from grazing occurred primarily on fine-textured soils on the study site.
    • State of Dry Matter and Nutrients of Soil-Plant Systems of Arizona Fescue and Mountain Muhly

      Klemmedson, J. O. (Society for Range Management, 1983-09-01)
      The state of dry matter, C, N, S and P for soil-plant systems of Arizona fescue and mountain muhly in the Arizona pine-bunchgrass community was determined as a first step to quantification of mineral cycles. These bunchgrass systems differed in stature, structure and accumulation of dry matter and nutrients, both on an absolute and per unit basal area basis for several components of the soil-plant systems. Dry matter/unit area was greater in fescue because of accumulation of standing dead vegetation and litter; weight of live shoots was 18% less in fescue than muhly. All 4 nutrients were present in greater concentrations and amounts in fescue than in muhly biomass, but accumulation patterns and influence on soil differed among nutrients. The standing state data suggest more rapid loss of dry matter and nutrients from muhly than fescue during senescence and decomposition.
    • The Suitability Of Commercially Available Grass Species for Revegetation of Montana Ski Area

      Behan, M. J. (Society for Range Management, 1983-09-01)
      Subalpine areas that were disturbed by ski run construction and then seeded with commercially available grass seed from 2 to more than 10 years ago were examined at 6 Montana ski areas. Species adaptability to subalpine environments was estimated by comparing the species that had become established with those that had been seeded, as well as by presence. Special notice was made of species that had persisted for a decade or longer. Bromus inermis, Festuca ovina, F. rubra, Dactylis glomerata, Agropyron trachycaulum, and A. dasystachyum had become successfully established and were persistent in most areas. These species should establish successfully in similar subalpine habitats if seeded for erosion control and revegetation.
    • Correlation of Honey Mesquite Response to Herbicides with Three Plant Variables and Soil Water

      Meyer, R. E.; Hanson, J. D.; Dye, A. J. (Society for Range Management, 1983-09-01)
      Honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] response to sprays of 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid) and picloram (4-amino-3,5,6-trichloropicolinic-acid) + 2,4,5-T was evaluated and correlated with maximum daily photosynthetic rate, upward movement of methylene dye, xylem pressure potential, and percent soil water. Picloram + 2,4,5-T was superior to 2,4,5-T alone for killing honey mesquite from May 15 through August 4. Time of day the herbicide was applied had no significant effect on control. Maximum daily photosynthetic rate varied from 32.9 to 10.1 mg ${\rm CO}_{2}\ {\rm dm}^{-2}$ leaf area hr-1 and was highly correlated (r = 0.89 to 0.92) with honey mesquite control with herbicides. Rate of upward movement of methylene blue dye in the xylom varied from 295 to 44 cm hr-1. (MPa) while soil water content varied from 11.5 to 18.6%. Upward movement of methylene blue dye, xylem pressure potential and percent soil water were not significantly correlated with honey mesquite control.
    • Density and Production of Seeded Range Grasses in Southeastern Arizona (1970-1982)

      Cox, J. R.; Jordan, G. L. (Society for Range Management, 1983-09-01)
      Accessions A-68, L-11, L-19, L-28, and L-38 of Lehmann lovegrass (Eragrostis lehmanniana Nees); P-15608 Cochise lovegrass (E. lehmanniana Nees X E. trichophora Coss & Dur.); A-84 and Catalina boer lovegrass (E. curvula var. conferta Nees); Palar Wilman lovegrass (E. superba Peyr.) and P-15630 blue panicgrass (Panicum antidotale Retz.) were seeded at a study site near San Simon, Ariz., in spring 1970 and 1971. Seedbeds were prepared by root plowing and furrow pitting immediately before planting. Growing season precipitation was 136 mm in 1970 and 218 mm in 1971. Mean accession densities in the fall after the initial growing seasons were 18 plants/m2 for both the 1970 and the 1971 plantings. Between fall 1971 and 1972 mean accession densities declined 44% and forage production was unchanged on the 1970 plantings. Accession densities declined 22% and forage production increased 250% on the 1971 plantings. Between fall 1972 and 1982 the majority of seeded plants died and forage production declined 90% on the 1970 plantings. Accession densities declined 78% and forage production declined 84% on the 1971 plantings.
    • Comparative Performance Oo Some Native and Introduced Grasses in Southern Saskatchewan, Canada

      Kilcher, M. R.; Looman, J. (Society for Range Management, 1983-09-01)
      This study reports on the poor performance of selected native grass species compared to that of certain adapted introduced and domesticated grasses. Of 12 grass species native to Canada and northern U.S.A., 7 showed very poor initial establishment. Subsequent winterkilling eliminated them. Of the 5 surviving native grass species only 2 attained a fair forage yield level compared to those of 5 domesticated grasses, and then only after the 3rd or 4th years of age. Most of the native species showed limited competition with weeds. Nutrient content, particularly crude protein, of the native grasses was not sustained as well as that in some of the tame grasses with advancing seasonal growth stages.