• Factors Influencing Microhistological Analysis of Herbivore Diets

      Vavra, M.; Holechek, J. L. (Society for Range Management, 1980-09-01)
      A study simulating herbivore diets was conducted to compare actual and estimated diet constituents as influenced by sample preparation technique and in vitro digestion. Nine plant species, three each representing grass, forb, and shrub forage classes were hand composited into three mixtures so that one forage class dominated each mixture. Samples of each mixture were then allotted to eight treatments involving combinations of grinding through a micro-Wiley mill, soaking in sodium hydroxide and in vitro digestion. Samples were then analyzed for botanical composition using the microhistological technique. In vitro digestion had the greatest impact on the difference between estimated and actual means. In digested samples grasses were overestimated while shrubs and forbs were underestimated. The preferred treatment involved grinding in a micro-Wiley mill and the sodium hydroxide soak.
    • Feral Horse Demography: A Preliminary Report

      Wolfe, M. L. (Society for Range Management, 1980-09-01)
      The demographic characteristics of 18 feral horse (Equus caballus) populations in five states are discussed. As estimated primarily from the results of composition counts, foals comprised an average 19 percent (post-parturition) of the populations analyzed. Various procedures were employed in an attempt to estimate survival rates within the populations. Provisional estimates of first-year survival rates span the general range of 50-70 percent, while those for adults may approximate 80-85 percent. Annual rates of increase, predicted from simulation runs with the estimated population parameters, were considerably lower than those "observed" from aerial inventories in successive years. Possible explanations for these discrepancies and management implications are discussed.
    • Growth Patterns and Biomass Relations of Xanthocephalum sarothrae (Pursh) Shinners on Sandy Soils in Southern New Mexico

      Nadabo, S.; Pieper, R. D.; Beck, R. F. (Society for Range Management, 1980-09-01)
      Growth patterns of broom snakeweed were studied on three areas of sandy range sites in southern New Mexico by measuring plant canopy biweekly during the growing season and calculating canopy volume. Canopy volume increased during the summer of 1977 on all three study areas. In 1978, canopy volume declined throughout much of the growing season because effective rainfall came late in the season. More than 60% of the canopy biomass was contributed by brown stems and leaves, about 30% by green leaves and stems, and less than 10% by inflorescences on most dates. Coefficients of determination relating canopy volume to canopy biomass were less than 0.70. Growth forms and patterns were quite variable among the populations studied.
    • Herbage Yields from a Clayey Range Site 10 and 11 Years after Severe Renovation

      Rauzi, F. (Society for Range Management, 1980-09-01)
      A clayey range site 56 km south of Gillette, Wyoming, was renovated in October, 1967, using a moldboard plow, disc plow, rotovator, blade, and atrazine applied in strips on April 30, 1968. Because of drought in 1977, there were no measurable differences in total herbage yield among all treatments 10-years after the renovation. However, the following year, 1978, above-average precipitation increased herbage yields, and differences among treatments were significant. Western wheatgrass (Agropyron smithii) yield, which accounted for over half the total production in 1977 and '78, was highest on the moldboard plow, the disc plow, and rotovator treatments, in that order.
    • Nonstructural Carbohydrates in Roots of Gambel Oak Sprouts Following Herbicide Treatment

      Engle, D. M.; Bonham, C. D. (Society for Range Management, 1980-09-01)
      Total nonstructural carbohydrate (TNC) concentrations in roots of Gambel oak sprouts as affected by herbicide applications were studied. TNC content varied significantly with changes in phenological stage and herbicide treatment. The storage cycle in sprout roots was found to differ considerably from that previously reported for roots of mature Gambel oak. Data from this study suggested that hormone-type herbicide applications should be made prior to the full leaf stage for maximum effectiveness. Roots of untreated oak sprouts in low densities contained significantly lower levels of TNC's compared to roots in high densities. No herbicide treatment reduced root TNC levels either 1 year following initial treatment or subsequent to second-year repeat applications. On the other hand, several herbicide treatments caused significant increases in root TNC's as compared with controls.
    • Quality, Yield, and Survival of Asiatic Bluestems and an Eastern Gamagrass in Southern Illinois

      Faix, J. J.; Kaiser, C. J.; Hinds, F. C. (Society for Range Management, 1980-09-01)
      Six Asiatic bluestems (Bothriochloa spp.) B. caucasica, cv. Caucasian, B. ischaemum var. ischaemum cv. Plains, and 4 experimental strains of B. Intermedia × B. ischaemum (B,L,LL, and T), and an Eastern gamagrass (Tripsacum dactyloides cv. PM-K-24) were grown in southern Illinois on a Typic Fragiudalf soil common to the Central U.S. Transitional Zone. The grasses were evaluated from 1975 through 1977 for yield, crude protein (CP), and in vitro digestibility (IVD) to determine their potential as alternatives to "summer dormant" tall fescue (Festuca arundinaceae) in southern Illinois. Average seasonal dry matter yields ranged from 10 to 15 metric tons per hectare. Eastern gamagrass was slower to establish than the bluestems, but after the first production year it was higher yielding than the bluestems. Forage CP and IVD averaged near 11 and 50%, respectively, over the 3-year period. There was little difference between the grasses for CP, but IVD of Caucasian bluestem was significantly lower than that of the other bluestems and Eastern gamagrass. All the grasses survived the three winters that yield and quality data were taken, but in two subsequent severe winters only Caucasian bluestem and the Eastern gamagrass were winter hardy.
    • Relating Fire Occurrence to Weather Conditions on the Great Basin Rangelands

      Hubbard, K. G. (Society for Range Management, 1980-09-01)
      Results are presented to demonstrate the association between weather conditions and fire danger on the rangelands of the Great Basin. It was found that precipitation frequency and duration are physically related to fire occurrence in a complex manner. A climatic relationship also exists between monthly temperature and the corresponding total number of fires for a specific area.
    • Seasonal Differences in the Element Content of Wyoming Big Sagebrush

      Gough, L. P.; Erdman, J. A. (Society for Range Management, 1980-09-01)
      Concentrations of 30 elements in samples from a stand of Artemisia tridentata subsp. wyomingensis Beetle & Young were determined for young and old tissue in September, January, April, and July, 1975-76. Elements with similar seasonal trends were grouped. Changes in the Concentration of the major essential elements (Ca, Mg, P, K, and S) with season directly reflect phenological events which alter the proportion of leaf-to-stem tissue in the samples. In general, the element composition of younger tissue fluctuates more, has higher concentrations, and shows greater differences between seasons than older material. These data stress the influence of season, on the element concentrations in plant tissue and underscore the need for caution when comparing sample data with established element concentration baselines.
    • Simulated Cattle Injury to Planted Slash Pine: Combinations of Defoliation, Browsing, and Trampling

      Lewis, C. E. (Society for Range Management, 1980-09-01)
      Cattle injure young pines by defoliating, browsing, and trampling them. Little is known about how these injuries at various levels and in various combinations will affect survival and growth of planted pines. Therefore, such injuries were simulated once on slash pine at 6, 18, and 30 months after planting by (1) hand clipping to remove needles, (2) clipping off the shoots, and (3) bending the stem at a right angle to the vertical. Survival was poorest when treatments were applied to seedlings within 6 months after planting, whereas mortality was low when older seedlings were treated. Only the severest treatments, especially combinations of injury, caused extreme mortality. Seedlings treated at 6 months after planting suffered greater reductions in height growth than did the older seedlings. Only the severest combinations of injury permanently reduced height growth.
    • Simulated Cattle Injury to Planted Slash Pine: Defoliation

      Lewis, C. E. (Society for Range Management, 1980-09-01)
      Animals sometimes injure trees by eating the leaves. Little is known about the amount of removal required to harm survival and growth, particularly of southern pines. To simulate a single defoliation by livestock or wildlife, needles of slash pine were hand clipped once at 6, 18, and 30 months after planting. Survival and height growth were measured for six growing seasons after removing 0, 25, 50, 75, and 100% of the foliage. Survival was excellent except when 100% of the needles were removed 6 months after planting. Reductions in rate of height growth occurred only with the most severe levels of defoliation and were still apparent for 3 years after treatment. Even so, the greatest accumulated loss in height was less than 1 m over the 6-year period.
    • Simulated Cattle Injury to Planted Slash Pine: Girdling

      Lewis, C. E. (Society for Range Management, 1980-09-01)
      Animals are known to girdle, or partially girdle, trees and shrubs by eating the bark or by knocking off the bark with their hooves. Since girdling has been observed in slash pine plantations being grazed by cattle, this form of injury was simulated on three ages of slash pine. Survival and growth were observed for 6 years after removal of a 5.1-cm-wide band of bark from around 50, 75, and 100% of the stem near groundline. Mortality was negligible except after complete girdling; even then, some seedlings lived. Height growth was reduced by the 75% girdle, primarily on seedlings treated within 6 months after planting. Two side tests on 100% girdles helped explain how trees can survive this severe injury.
    • Strains of Blue Grama and Sideoats Grama Evaluated for the Southern Great Plains

      Pitman, W. D.; Jaynes, C. C. (Society for Range Management, 1980-09-01)
      Strains of blue grama and sideoats grama were evaluated for forage yield and quality under dryland conditions on the Southern Great Plains. In vitro dry matter digestibility (IVDMD) and crude protein content were determined as measures of forage quality. WW 65 blue grama was the leading strain of blue grama for every parameter measured, but it was significantly greater than the other blue grama strains only in IVDMD. Although no strain of sideoats grama proved superior in forage yield, PMT 328 sideoats grama was highest in crude protein content and was significantly greater than all other strains of sideoats grama in IVDMD. WW 65 blue grama and PMT 328 sideoats grama exhibited superior forage quality with at least comparable forage yield to the other strains of blue grama and sideoats grama, respectively.
    • Susceptibility of Selected Woody Plants to Pelleted Picloram

      Kitchen, L. M.; Scifres, C. J.; Mutz, J. L. (Society for Range Management, 1980-09-01)
      Picloram pellets, aerially applied at 1.1 kg/ha in the spring to South Texas mixed-brush, effectively controlled spiny hackberry and pricklypear, and 2.2 kg/ha temporarily controlled blackbrush acacia. However, agarito, desert yaupon, lotebush, Texas persimmon, and whitebrush were only slightly susceptible to soil applications of picloram, and honey mesquite and creeping mesquite were tolerant. Range site exerted a significant influence only with initial defoliation of twisted acacia. Although canopy reduction of twisted acacia after one growing season was higher on Shallow than on Rolling Blackland or Claypan Prairie range sites, it was apparently only moderately susceptible to pelleted picloram. Shredding prior to pellet applications did not improve the level of brush control compared to applying the picloram to undisturbed brush stands. There was no consistent difference in brush control within an application rate between 5% or 10% active ingredient formulations of picloram pellets.
    • The Effects of Subsurface Irrigation on Current and Subsequent Year's Growth in Shadscale

      Johnson, P. S.; Norton, B. E. (Society for Range Management, 1980-09-01)
      Sursurface irrigation of individual Atriplex confertifolia (shadscale) plants was implemented in the field during the summer of 1976 through the use of vertical access tubes to a depth of 50 cm. Shoots were marked on control and watered plants and examined periodically by enumerating every leaf, bud, flower, fruit, and second-order stem. Plant response to subsurface irrigation as determined in the fall enumeration revealed a modest increase in stem length and leaf weight and summer production of lateral branches. The carryover effect of summer irrigation was reflected in new growth on shoots of watered plants in spring 1977 being more than twice the production of shoots on controls. The 1976 response to subsurface irrigation is thought to be carbohydrate storage and/or root development. Watering did not enhance bud or shoot survival overwinter.
    • White-Tailed Deer Densities and Brush Cover on the Rio Grande Plain

      Steuter, A. A.; Wright, H. A. (Society for Range Management, 1980-09-01)
      Rio Grande Plain habitats with a range in total brush cover from 10 to 97% were selected from three brush control treatments and native brush types. Deer density in each habitat was determined from helicopter census and observation towers. Three brush cover classes resulted in three levels of white-tailed deer use during summer. Areas with less than 43% total brush cover had a maximum density of 1.4 deer/40.5 ha. Brush cover from 43 to 60% had a maximum density of 3.25 deer/40.5 ha. Highest summer deer use occurred on areas with 60 to 97% total brush cover (7.5 deer/40.5 ha).