• Chemically Thinning Blue Grama Range for Increased Forage and Seed Production

      McGinnies, W. J. (Society for Range Management, 1984-09-01)
      Forage and seed production of blue grama rangeland can be increased by chemically thinning the native grass stand. Thinning of native blue grama range was accomplished by spraying strips 30 cm wide with glyphosate [N-(phosphonomethyl) glycine] and leaving alternating 15 cm wide strips of undisturbed vegetation. This reduced the stand to one-third of its original ground cover. Forage production was increased an average of 37% over the untreated pastures during a 7-year period. Plants in the thinned area were taller and had a more upright growth form which made the herbage more readily available to livestock. When plants were grazed during the winter, 67% more animal days of grazing were obtained from the thinned pastures than from the untreated pastures. For the 5 years when seed was harvested, production of clean seed averaged 5.6 kg/ha on the untreated pastures and 13.0 kg/ha on the thinned pastures.
    • Circumstances Associated with Predation Rates on Sheep and Goats

      Nass, R. D.; Lynch, G.; Theade, J. (Society for Range Management, 1984-09-01)
      Factors possibly associated with high (over 5%) and low (0-5%) predation intensities were compared among 95 sheep or goat producers in 5 states to determine if important differences were evident between the 2 groups. Data were compared for the following variables: losses to predation, flock size, type of ranch operation, management practices, predator indices, prey indices, use of U.S. Animal Damage Control program, private control efforts, predation history, timing of predation, and presence of other sheep or goats nearby. Overall, 45% of the producers reported over 5% predation losses of their lambs or kids and predation percentages tended to increase with decreased flock sizes. Feeder lamb and range sheep operations had predominantly low predation loss percentages, but most operations that included goats reported over 5% predation losses due to goat predation. A variety of management practices were used by both groups; however, low loss producers indicated low natural prey and predator populations. Most of the producers used the federal ADC program and some type of private control effort, although more high loss producers used both types. Rough, bottom, and brush grazing lands, historic predation problems, and high predator indices characterized many of the high loss producers.
    • Climax Theories and a Recommendation for Vegetation Classification—A Viewpoint

      Meeker, D. O.; Merkel, D. L. (Society for Range Management, 1984-09-01)
    • Effects of Fire on Texas Wintergrass Communities

      Whisenant, S. G.; Ueckert, D. N.; Scifres, C. J. (Society for Range Management, 1984-09-01)
      The effect of season of burning on standing crop, point frequency, density, and reproductive vigor of Texas wintergrass (Stipa leucotricha Trin. & Rupr.) communities was measured in this study. Additional information on the effects of fire on Texas wintergrass will aid resource managers plan the use of fire in these communities. Burning or clipping Texas wintergrass did not significantly affect the number of reproductive culms per plant in the northern Edwards Plateau region of Texas. Burning, regardless of season, reduced standing crops for 1 year and burning in January or March reduced Texas wintergrass point frequency for 1 year. Burning where annual cool-season grasses were abundant in the southern Rolling Plains tended to increase Texas wintergrass density, point frequency, and standing crop, apparently a result of reduced competition from annual plants. Increases in Texas wintergrass point frequency and standing crop were greater following burning in the fall than following burning in the spring. Prescribed burning in Texas wintergrass communities generally killed annual grasses and forbs if burning occurred subsequent to seedling emergence. However, soil reserves of seed and/or subsequent seed immigration into burned areas appeared to be sufficient to reestablish populations of annual plants during the second year following burning. Annual grass populations consistently tended to be higher in the second year after burning than on unburned rangeland.
    • Effects of Temporary Dehydration on Growth of Green Needlegrass (Stipa viridula Trin.) Seedlings

      Fulbright, T. E.; Wilson, A. M.; Redente, E. F. (Society for Range Management, 1984-09-01)
      Green needlegrass (Stipa viridula Trin.) has been variously rated as "extremely" to "fairly" drought tolerant. This study was conducted to determine the capacity of green needlegrass seedlings for emergence and root growth following temporary dehydration. Germinating seeds were exposed to dehydration treatments of 0, -4, -10, -22, and -37 megapascals (MPa) and then planted in soil-filled pots for a 10-day growth performance test. Exposure of germinating seeds to temporary dehydration treatments of -10 MPa and lower reduced subsequent seedling emergence. When the seminal primary root of germinating seeds was excised or injured by dehydration, seedlings developed up to 3 seminal lateral roots. No additional seminal roots were developed if the seminal primary root was undamaged. Germinating seeds of green needlegrass have relatively low tolerance to dehydration possibly as a result of a low latent potential for development of seminal lateral roots and low tolerance of the embryo and developing tissues to dehydration. Sites to be seeded and planting dates should be selected so as to insure adequate soil moisture for seedling development.
    • Burning of Northern Mixed Prairie During Drought

      Engle, D. M.; Bultsma, P. M. (Society for Range Management, 1984-09-01)
      Standing crop of current year's growth and response of key management species were evaluated following burning in mid-May (before emergence of warm-season grasses) and mid-June (after emergence of warm-season grasses). The study was conducted during 2 dry years in a mesic Mixed Prairie in South Dakota. Cool-season precipitation was 33% below average in both years of the study, while warm-season precipitation was only slightly below average both years. Standing crop of current year's growth was increased by burning on overflow range sites, but not on silty range sites. Big bluestem (Andropogon gerardi) standing crop was greatest with mid-May burning. Kentucky bluegrass (Poa pratensis) standing crop and leaf length were reduced with burning on both dates. Leaf length, basal area and number of inflorescences of native cool-season grasses were also reduced. Mid-May burning in drought years may be recommended for the reduction of Kentucky bluegrass. However, reductions in production of native cool-season vegetation can be expected on silty range sites. In contrast, mid-June burning in dry years is not recommended.
    • Seasonal Variation in Total Nonstructural Carbohydrate Levels in Nebraska Sedge

      Steele, J. M.; Ratliff, R. D.; Ritenour, G. L. (Society for Range Management, 1984-09-01)
      Seasonal variation in total nonstructural carbohydrate (TNC) levels in rhizomes and shoots of Nebraska sedge (Carex nebraskensis Dewey) suggest that grazing too early or too late or both may be detrimental. Samples were collected from a natural population of Nebraska sedge growing in Tule Meadow at 2,170 m elevation in the Sierra Nevada, Calif. TNC reserves in rhizomes decreased to 7.5% of the dry weight during early shoot growth, and reached a peak level of 17.4% in the fall. TNC levels in shoots ranged from a low of 10.6% in the spring to a high of 16% in August, after flowering. TNC levels in emerging shoots averaged 16.4% in September and 19.1% at the end of October.
    • Vegetation of Two Relict Mesas in Zion National Park

      Madany, M. H.; West, N. E. (Society for Range Management, 1984-09-01)
      Twelve permanent vegetation sampling plots were established on Greatheart and Church mesas in Zion National Park, Utah. Both relict mesas are surrounded by cliffs but contain the same variety of soil conditions as the nearby "mainland." The mesa vegetation was segregated into the following broad community types: mixed conifer forest, ponderosa pine savanna, Gambel oak woodland, pinyon woodland, snowberry-sagebrush steppe, and oak-sagebrush shrubland. Cover of all species was measured in the plots, in addition to tree stem density. Relationships of each community type to topo-edaphic factors and response to fire are noted. The mesa ecosystems can be used as standards to gauge the various effects of resource exploitation on analogous "mainland" areas.
    • Livestock Impacts on Riparian Ecosystems and Streamside Management Implications...A Review

      Kauffman, J. B.; Krueger, W. C. (Society for Range Management, 1984-09-01)
    • Long-Term Effects of Annual Burning at Different Dates in Ungrazed Kansas Tallgrass Prairie

      Towne, G.; Owensby, C. (Society for Range Management, 1984-09-01)
      Ungrazed tallgrass prairie plots in the Kansas Flint Hills have been burned annually at 4 different dates since 1928. Time of burning markedly altered the physiognomy and was the crucial factor effecting vegetation change. Late-spring burning, coinciding with emergence of the warm-season perennial grasses, increased grass production and favored Andropogon gerardii and Sorghastrum nutans. Burning in winter, early-spring, or mid-spring reduced herbage production and shifted vegetational composition by differentially favoring other species. Andropogon scoparius increased with mid- and early-spring burning, while perennial forbs and sedges increased with early-spring and winter burning. Amorpha canescens was favored by all burning treatments. Mulch buildup in unburned, undisturbed plots increased Poa pratensis and tree species and eventually reduced grass production. The long-term effects of annual late-spring burning, even in dry years, was not detrimental to herbage production, species composition, or total basal cover in tallgrass prairie.
    • Fire Effects on Nitrogen Mineralization and Fixation in Mountain Shrub and Grassland Communities

      Hobbs, N. T.; Schimel, D. S. (Society for Range Management, 1984-09-01)
      Prescribed burns were carried out in mountain shrub and grassland communities in the montane zone of the Rocky Mountains in Colorado. Nitrogen mineralization rate was increased 1 year after the burn in both communities. This increase persisted for 1 year in the grassland and for 2 years in the shrub community. Total mineralized soil-N was greater in the burned than unburned areas of both communities during the first growing season after fire. An acetylene reduction assay for nitrogenase activity showed depressed activity 1 year after the burn. We suggest that elevated inorganic N levels caused the reduction in nitrogenase activity.
    • Reliability of Captive Deer and Cow In Vitro Digestion Value in Predicting Wild Deer Digestion Levels

      Campa, H.; Woodyard, D. K.; Haufler, J. B. (Society for Range Management, 1984-09-01)
      The in vitro dry matter digestibility (IVDMD) values of 9 forages were compared using rumen fluid collected from wild white-tailed deer (Odocoileus virginianus), captive white-tailed deer, and a Holstein cow. Five of the 9 forages analyzed displayed significantly different (P<0.05) IVDMD between wild deer and captive deer inocula and between wild deer and cow inocula. Differences were attributed to the diet differences of the donor animals, which may have influenced the composition of microorganisms within the rumen. In vitro dry matter digestibility of all 5 forages considered together decreased significantly (P<0.05) when rumen inocula were stored at various intervals. This study indicates that IVDMD values obtained using inoculum from captive and domestic animals on commercial diets should only be used by researchers to make comparisons of forages, not to predict actual digestibility levels by wild animals. In addition, in vitro samples should be inoculated as soon after collection as possible in order to obtain reliable data.
    • Spatial and Seasonal Variability of Field Measured Infiltration Rates on a Rangeland Site in Utah

      Achouri, M.; Gifford, G. F. (Society for Range Management, 1984-09-01)
      This study was conducted to examine both spatial and temporal variability of infiltration rates on a rangeland site in west-central Utah. The experiment utilized a grid 20 m long and 18 m wide in both grazed and ungrazed sites with a sample spacing of 2 m within the grid. To investigate the seasonal effect on variability of infiltration rates, data were collected for 3 seasons (summer, fall, and spring). Measured infiltration rates at 10 and 30 min during all seasons and under grazed versus ungrazed conditions were all found to approximate a two-parameter log normal distribution. Regionalized variable theory was applied to the data through the development of autocorrelograms and semivariograms, revealing a complete lack of variance structure among the infiltration rates. This finding excluded the possibility of using the Kriging technique for interpolation. Seasonal effect was found to be very important in influencing infiltration rates. The difference between the measured infiltration rates at both grazed and ungrazed sites was very significant for the 3 seasons under study.
    • Estimating Grazingland Yield from Commonly Available Data

      Wisiol, K. (Society for Range Management, 1984-09-01)
      Range managers must often estimate or predict annual forage yield at a distance, from minimal data, or for a variety of sites. This study compared and modified 6 simple formulas potentially useful for this purpose. The grazingland data that were used represented 44 sites on 5 continents. Soil texture at site affected accuracy of all formulas. Shrubbiness affected accuracy of formulas based on evapotranspiration. Some formulas modified to include past-year yield as a variable were fairly accurate over a variety of grazinglands. An equation based only on past-year yield predicted yield within an average of 34% at new sites. Equations that incorporated past-year yield, used a measure of current effective moisture, and had a limiting-factor approach estimated current yield within an average of 18-19% at new sites.
    • Grazing Management Impacts on Quail During Drought in the Northern Rio Grande Plain, Texas

      Campbell-Kissock, L.; Blankenship, L. H.; White, L. D. (Society for Range Management, 1984-09-01)
      Relationships between the abundance of 2 quail species and range site and grazing management during drought were evaluated in the northern Rio Grande Plain of Texas. Clay loam range sites provided better nesting cover and greater abundance of forbs for quail than sandy loam and shallow ridge range sites. Foliar cover and aboveground standing crop of grass were greater on the 3 range sites within the short duration and deferred rotation systems as compared with the yearlong system. During drought, grazing systems provided better nesting and protective cover for quail than yearlong grazing.
    • Impact of Small Mammal on the Vegetation of Reclaimed Land in the Northern Great Plains

      Hingtgen, T. M.; Clark, W. R. (Society for Range Management, 1984-09-01)
    • Shoot Growth and Development of Alamo Switchgrass as Influenced by Mowing and Fertilization

      Haferkamp, M. R.; Copeland, T. D. (Society for Range Management, 1984-09-01)
      The response of shoot development and forage yield of a 2-year old 'Alamo' switchgrass stand to mowing and fertilization was evaluated to provide information needed for effective management of this variety. Mowing to a 20-cm stubble height in mid-spring removed only a few apical meristems and had little impact on shoot development. Late spring and early summer mowing were done when apical meristems of primary compound shoots were elevated to near the 20-cm cutting height in May and over 20 cm in June. Secondary nonrooted shoot and aerial shoot numbers were increased and plant vigor, measured by spring growth in 1980, was decreased slightly the following spring. Mowing in mid-summer removed apical meristems from essentially all primary compound shoots and many secondary compound shoots. Regrowth was slight during the remainder of the summer, but the number of secondary and tertiary nonrooted shoots and aerial shoots increased. The number of proaxis buds decreased, and plant vigor was severely decreased the following spring. Mowing twice including early fall, removed apical meristems from secondary compound shoots and some primary and secondary nonrooted shoots. Numbers of secondary, tertiary, and quarternary nonrooted shoots increased, but proaxis bud numbers were reduced. Plant vigor was very low the following spring, possibly due to exposure of mowed plants to cold winter temperatures. Fertilization increased the rate of development of compound and nonrooted shoots, the number of secondary and compound shoots in spring, the number of proaxis buds in fall and the weight of primary and secondary compound shoots. Fertilized stands mowed during summer and early fall were more productive than all other mowed stands. Fertilized plants mowed in mid-summer were vigorous and productive the following spring. However, fertilization did not overcome the loss of vigor caused by fall mowing.
    • Some Aspects of Rangeland Improvement in a Derived Savanna Ecosystem

      Omaliko, C. P. E.; Mammah, O. A.; Agbakoba, A. M. (Society for Range Management, 1984-09-01)
      Natural rangelands carry the bulk of ruminant livestock in the tropics of Nigeria. However, the productivity of such ecosystems is low. Some improvement of the rangelands' productivity is, therefore, needed and in this experiment the effects of fertilizers, legume oversowing, and harvesting management were evaluated. Dry matter yield increased from 3,400 kg/ha with zero fertilizer to 6,600 kg/ha with a combination of 200kg N, 44kg P, and 83kg K per hectare. NPK × 6 weeks cutting interval gave the highest dry matter yield. Crude protein concentration and botanical composition of the herbage as well as the site's soil chemistry were altered by the treatments. Application of NPK fertilizers and harvesting every 6 weeks were, at least for this ecological zone, the best way of improving the rangeland and sustaining the improvement for long-term productivity.
    • Ozone-Treated Mesquite for Supplementing Steers in West Texas

      Bryant, F. C.; Mills, T.; Pitts, J. S.; Carrigan, M.; Wiggers, E. P. (Society for Range Management, 1984-09-01)
      Ozonated-mesquite was compared with cottonseed hulls as the fiber base in supplemental rations fed to growing steers under range conditions. Average daily gains of steers fed the 2 rations for the 2 winter feeding periods were similar. Similarities in concentrations of acetic, propionic, and butyric acids, and acetic:propionic acid ratios between rations indicated no alterations in production of these acids as affected by composition or physical form of the ozonated-mesquite. Therefore, ozonated-mesquite appears to be equal in value to cottonseed hulls as a roughage base in supplemental rations fed to range steers.
    • The Effect of Phytophagous Nematode Grazing on Blue Grama Die-off

      Stanton, N. L.; Morrison, D.; Laycock, W. A. (Society for Range Management, 1984-09-01)
      Nematode populations were sampled in ungrazed and heavily grazed areas in northeastern Colorado under patches of healthy, senescing, and dead blue grama to test the hypothesis that phytophagous nematodes may cause the senescence. Densities of plant parasites were significantly different under the 3 plant types. Live blue grama supported the highest numbers (1.2 X 10^6 m2) and dead blue grama, the lowest (2 X 10^5 m2). Bacterial feeding nematodes also varied significantly with plant type. Highest densities were found under senescing plants (2.4 X 10^6 m2) and lowest densities were under dead plants (7 X 10^5 m2). Total densities were slightly but insignificantly lower in the heavily grazed area. Scarlet globemallow and fringed sagewort supported lower populations of both plant parasites and bacterial feeders than did live blue grama. The densities under live blue grama were not unusually high and well within the values reported in the literature for arid grasslands. Thus, nematode root grazing may decrease net primary production but we conclude that nematodes themselves were not the major cause of the die-off.