• 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).