• Yaupon and Associated Vegetation Response to Seasonal Tebuthiuron Applications

      Duncan, K. W.; Scifres, C. J. (Society for Range Management, 1983-09-01)
      Broadcast applications of tebuthiuron pellets (20% active ingredient [a.i.]) at 2 kg/ha (a.i.) in spring more effectively controlled yaupon than applications in summer, fall or winter on the Post Oak Savannah. Tebuthiuron applications in spring reduced the live canopy of yaupon by 80%. Tebuthiuron at 1 kg/ha did not effectively control yaupon, regardless of season of treatment. Herbaceous response to tebuthiuron was relatively slow because of lack of a seed source in the heavy yaupon covers. However, by December 1980 after applications of tebuthiuron at 2 or 4 kg/ha in spring or summer 1978, grass standing crops were significantly increased. Forb standing crops were highly variable, but there was no apparent forb reduction in 1980 of 1981 where herbicide was applied in 1978-1979.
    • 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 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • Seed Germination Characteristics of Kochia scoparia

      Everitt, J. H.; Alaniz, M. A.; Lee, J. B. (Society for Range Management, 1983-09-01)
      Kochia (Kochia scoparia) seed germination was investigated in relation to various regimes of temperatures and light, salinity, pH, and osmotic potential. Germination was highest at cool to moderate temperatures. Percentage germination was greater than or equal to 88% at continuous temperatures of 5 to 25 degrees C and at alternating temperatures of 5-15, 10-20, 15-25, and 20-30 degrees C. Percentage germination was not higher at alternating than with constant temperatures. Light was not required for germination. Germination was not affected by 6 salts (NaCl, CaCl2, MgCl2, KCL, Na2 SO4, and MgSO4) at conductances up to 20 mmhos. Increasing conductances of NaCl and CaCl2 solutions from 25 to 40 mmhos by 5 mmho increments progressively reduced germination. Germination was ≥40% in the 40 mmhos conductance of both salts. Kochia seed germination was highly tolerant of extremes of pH and was not reduced by simulated moisture stress until osmotic potential reached -8 bars. Seedling emergence for kochia seeds left exposed on the soil surface was significantly higher than those buried with soil.
    • Seasonal Effects of Nitrogen Fertilization on Three Species of South Texas Browse Plants

      Everitt, J. H.; Gausman, H. W. (Society for Range Management, 1983-09-01)
      We conducted a study in Kenedy County of south Texas to determine nitrogen (N) fertilization effects on crude protein (CP), P, Ca, K, and Mg contents of 3 important deer browse plants (granjeno, Celtis pallida; lime pricklyash, Zanthoxylum fagara; and bluewood, Condalia hookeri). Four N fertilizer rates (56, 112, 168, and 224 kg N/ha) were applied in February 1980 to improved rangeland plots where brush was reinfesting. Control plots were nonfertilized. Vegetation samples were assayed for CP, P, Ca, K, and Mg contents on 5 dates: June, September, and December 1980, and April and July 1981. The CP content of plants fertilized with 112 kg N/ha or more was significantly higher (P = 0.05) than those fertilized with 56 kg N/ha or nonfertilized. Except for lime pricklyash plants fertilized with 224 kg N/ha, the CP content of plants fertilized with 168 and 224 kg N/ha was not significantly different from those fertilized with 112 kg N/ha. The addition of 56 kg N/ha had no effect on the species' CP content. Nitrogen fertilization had little effect on the P, Ca, K, and Mg contents of the species. The 3 species from both nontreated and treated plots had adequate CP, Ca, K, and Mg levels for deer nutritive requirements throughout the study, but P levels were generally deficient except in April 1981.
    • Rotational vs. Continuous Grazing Affects Animal Performance on Annual Grass-Subclover Pasture

      Sharrow, S. H. (Society for Range Management, 1983-09-01)
      Performance of Romney ewes and their lambs grazing an annual grass-subclover hill pasture was evaluated under both five-paddock rotational and continuous grazing management treatments during 1977 and 1978. Live weight gains of ewes and lambs tended to be greater under rotational than under continuous grazing during the spring or fall green-feed periods. During the summer dry-feed period, however, sheep maintained their body weight better under continuous than under rotational grazing. These data support the hypothesis that rotational grazing most effectively improves animal performance during the green-feed period, perhaps through its regulation of pasture production.
    • Responses of Semidesert Grasses and Shrubs to Fall Burning

      Martin, S. C. (Society for Range Management, 1983-09-01)
      Four 0.8-ha plots south of Tucson, Ariz., were burned November 12, 1975, in a pasture where cattle had not grazed for 12 months. The fire top-killed most small mesquites, killed almost all of the burroweed and much of the cactus, except in unburned patches. Within 5 years regrowth of mesquite and newly established stands of burroweed equalled or exceeded pre-burn levels. Lehmann lovegrass increased following the burn; most other perennial grasses were not greatly affected. Results suggest that periodic burning can maintain a grassland aspect if the intensity and frequency of grazing allow enough dry herbage for an effective fire to accumulate between burns.
    • Relationship of Relative Total Alkaloid Concentration and Toxicity of Duncecap Larkspur during Growth

      Olsen, J. D. (Society for Range Management, 1983-09-01)
      The toxicity of duncecap larkspur (Delphinium occidentale Wat.) was measured by a mouse bioassay and correlated relative to total alkaloid concentration for 5 samples during one season of plant growth. The concentration coefficient was -0.920 (standard error of estimate = 0.090) when this relationship was described by an exponential equation of the form Y = ab^x, where Y equals the total alkaloid concentration and X equals the LD50 for mice. The values a and b were estimated to be 5.410 and 0.978, respectively. It is predicted that over the entire growing season, toxicity of larkspur measured by mouse bioassay will be better correlated with toxicity to cattle than will be the correlation of relative total alkaloid content and toxicity to cattle.
    • Path Coefficient Analysis of Seed Yield in Big Bluestem

      Boe, A.; Ross, J. G. (Society for Range Management, 1983-09-01)
      Path coefficient analysis was performed on 19 spaced-plant, open-pollinated big bluestem (Andropogon gerardii Vit.) progenies to determine direct and indirect effects of seed yield components (number of flowering culms, florets per culm, fertility index, and seed weight) on seed yield. Seed yield was positively correlated with all its components. Number of flowering culms, florets per culm, and fertility index had substantial direct effects, in that order, on seed yield. The significant positive total correlation between seed weight and seed yield resulted from positive indirect effects of florets per culm and fertility index. The negative indirect effect of number of flowering culms substantially reduced total correlations between seed yield and fertility index and florets per culm. Correlations between forage characters and number of flowering culms and seed yield were highly significant. Number of flowering culms was negatively correlated with seed weight, fertility index, and floret per culm.
    • Modeling Big Sagebrush as a Fuel

      Frandsen, W. H. (Society for Range Management, 1983-09-01)
      Sufficient data exist within the literature to allow the woody biomass of two subspecies of Artemisia tridentata, basin big sagebrush (Artemesia tridentata ssp. tridentata), and Wyoming big sagebrush (Artemesia tridentata ssp. wyomingensis), to be classified into 3 standard fuel size classes: 0 to 1/4 inch (0 to 0.63 cm), 1/4 to 1 inch (0.64 to 2.54 cm), and 1 to 3 inches (2.55 to 7.62 cm). Of primary significance to fire behavior is a technique wherein the biomass is modified and expressed as a fuel load referenced to the canopy area. A table relates the fuel load by size class to the height and canopy area of the shrub. Estimates of the average load by size class-necessary for predicting fire behavior-can be made for areas where the shrub dimensions and number densities are known. Those less interested in fire will find this table an easy-to-use reference to the physical description of these shrubs. Although classification of the woody biomass by size class was a major result, regressions of the leaf and woody biomass on canopy area and height and regressions of canopy area on height are presented on a comparable basis for both subspecies. Regressions of biomass on height and canopy area suggest that wyomingensis is similar to tridentata up to a shrub height of 0.8 m where the biomass for similar crown dimensions increases 1.5 and 1.8 fold at greater heights.
    • Low-energy Grubbing with Special Blade to Control Algerita

      Cross, B. T.; Wiedemann, H. T. (Society for Range Management, 1983-09-01)
      Algerita (Berberis trifoliolata Moric) infestations on low stony hill range sites in the Edwards Plateau vegetational area of Texas are a problem following primary brush control. Infestations appear well suited to control by low-energy grubbing. A feasibility study indicated the method was economical but plant kill was erratic. Sprouting of lateral roots near the periphery of the grubbed hole accounted for 56% of the regrowth while 13% was attributed to crown tissue attached to taproots. No sprouts originated directly from taproots. Remaining regrowth resulted from problems with blade penetration in the soil. To prevent sprouting, severing the taproot below the crown and uprooting of all lateral roots under the entire plant canopy to a depth of 10 to 15 cm was necessary. Grubber blade modification included an increase in width to 180 cm and an addition of small fins welded on top of the blade to increase plant uprooting. Grubbing with the modified blade resulted in a plant kill of 93% +/- 3.5 (x +/- S.D.) when tested in an algerita infestation of 42 to 195 plants/ha ranging in height from 1.0 to 1.5 m. The grubber averaged 2.13 ha/hr in a 110 plants/ha infestation and cost of $16.43/ha. The ha/hr grubbing rate (Y) plotted against trees/ha densities (X) followed the prediction equation log Y = 1.93 - 0.83 log X with a significant (P<0.01) correlation coefficient of r = 0.91. Low-energy grubbing using the modified grubbing blade is an effective and economical method of controlling algerita.
    • Landsat Computer-aided Analysis Techniques for Range Vegetation Mapping

      McGraw, J. F.; Tueller, P. T. (Society for Range Management, 1983-09-01)
      Landsat computer-aided analysis techniques were used to map the sagebrush-grass vegetation of northern Nevada. A final Landsat digital classification resulted in 14 spectral classes representing 8 range plant communities. Classification accuracy for all sample plots was 86.4%, with individual class accuracies ranging from 77.8 to 95.4%. Classification methods included supervised, unsupervised, and guided clustering techniques using a maximum likelihood classifier.
    • 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.