• Measurement of Seasonal Air Temperatures Near the Soil Surfaces

      Fowler, W. B. (Society for Range Management, 1971-03-01)
      A study of the maximum air temperature near the soil surface at 11 grassland locations was made during the summer of 1968 using a simple maximum temperature indicator. Maximum temperatures within the first centimeter above the soil were found to exceed 144 F on a number of these locations. Although the range of indicators was not large enough to include the extremes at all locations, a seasonal pattern was identifiable. Large local differences in near-surface temperatures were frequently observed.
    • Mesquite Twig Girdler: A Possible Means of Mesquite Control

      Ueckert, D. N.; Polk, K. L.; Ward, C. R. (Society for Range Management, 1971-03-01)
      The mesquite twig girdler (Oncideres rhodosticta Bates) was found to inflict considerable damage to mesquite in Texas and may prove to be a valuable biological control agent for this noxious species. Preliminary observations in infested areas indicated that about 90 percent of the mesquite trees had been attacked by the girdler and that about 40 percent of all branches from 0.5 to 2.0 cm in diameter had been girdled.
    • Nature of Phytomer Growth in Blue Grama

      Stubbendieck, J.; Burzlaff, D. F. (Society for Range Management, 1971-03-01)
      The pattern and relative growth rates of the individual phytomers of blue grama were determined. A mature blue grama shoot from the site had an average of 13 complete phytomers. The first six phytomers appeared to be initiated in the growing season prior to the one in which the plant reached maturity. Internodal elongation of over 100 mm in a period of two weeks was not uncommon. In most instances the internodes did not elongate before the sheath and blade reached maximum length. The leaf of the last phytomer was initiated just prior to the middle of June. Mature sheath length varied from 15 mm in phytomer 13 to nearly 80 mm in phytomers 11 and 12. Blade length varied from 4 mm in phytomer 2 to 134 mm in phytomer 10.
    • Nutritive Value of Forage and Diets of Sheep and Cattle from Oregon Subclover-Grass Mixtures

      Bedell, T. E. (Society for Range Management, 1971-03-01)
      During spring-summer over a three-year period, selectivity by both sheep and cattle grazing on subclover-perennial ryegrass and subclover-tall fescue resulted in higher nutritive value of diets than of ungrazed forage. Sheep diets consistently contained more crude protein and had higher in vitro dry matter digestibility than did cattle diets. Both sheep and cattle diets were more digestible under light than under heavy grazing but diet protein levels were inconsistent. In one year stocking rate had no effect on level of protein in the diet and the next year high protein levels were associated with heavy use. Summer vegetative regrowth of tall fescue caused by heavy cattle grazing resulted in levels of dietary protein for cattle similar to those for sheep. The level of dietary protein for sheep exceeded recommended requirements. In the summer, protein levels of cattle diets were near or below requirements except when cattle heavily grazed subclover-tall fescue pastures.
    • Optimum Stand Selection for Juniper Control on Southwestern Woodland Ranges

      Jameson, D. A. (Society for Range Management, 1971-03-01)
      The optimum time for a land improvement investment when both cost and benefits are changing is when the rate of change of benefits equals the rate of change of costs. This principle can be applied to selecting optimum weed-tree stands for control operations where stands are present in a variety of age classes. If the cost of the control method is fixed, older stands with zero rate of tree cover change represent optimal treatment areas, but if the cost of the control method increases with stand age, young stands represent optimal treatment situations.
    • Range Resources of Iceland

      Thorsteinsson, I.; Olafsson, G.; Van Dyne, G. M. (Society for Range Management, 1971-03-01)
      Animal agriculture in Iceland is second only to fisheries. At least half the forage consumed by large herbivorous animals comes from rangelands. During the period June to September most of the sheep and large numbers of unbroken horses graze on mountain ranges where they roam freely in large grazing districts or commons. There is urgent need for land reclamation and range improvement. Only 25% of the country is covered with vegetation, much of which does not provide adequate protection against soil erosion and has low carrying capacity. With increasing population and demands upon rangelands for food production, an aggressive program of rangeland improvement and management, supported by adequate research, is essential.
    • Seed Dispersal in Relation to Rodent Activities in Seral Big Sagebrush Communities

      La Tourrette, J. E.; Young, J. A.; Evans, R. A. (Society for Range Management, 1971-03-01)
      Heteromyid rodents play an active role in the dispersal of caryopses and seeds of herbaceous species in degraded big sagebrush communities. Collections of caryopses of downy brome, deposited in caches, influence the dynamics of the grass population and the diet of animals on range sites in winter. Seeds and caryopses of alien weeds and exotic wheatgrasses were recovered more frequently from the pouches of rodents than seeds of native species.
    • Sheep Behavior Under Unherded Conditions on Mountain Summer Ranges

      Bowns, J. E. (Society for Range Management, 1971-03-01)
      Purebred Rambouillet, Targhee and Columbia sheep were observed on mountain summer ranges in southwestern Utah. Under unherded conditions Rambouillet sheep travelled greater distances and spent more time resting, while Columbias travelled the least distances, rested least and grazed longer than the other breeds. All breeds travelled farther in the morning than in the afternoon but grazed longer in the afternoon. There was a tendency for the sheep to water and take salt in the mornings rather than in the afternoons. Overgrazing on established bedgrounds was caused by animals grazing these areas in the evening prior to bedding down. Fencing along the crests of the ridges and more strategic salt placement appear to be the most useful means of improving distribution.
    • Spraying Tarweed Infestations on Ranges Newly Seeded to Grass

      Hull, A. C. (Society for Range Management, 1971-03-01)
      A high elevation, tarweed-infested range which had been newly seeded to grass was sprayed with 3 rates of 2,4-D at 2 growth stages of the seeded grass. 2,4-D at 0.5 lb./acre killed over 97% of the tarweed and 1 and 2 pounds killed 99 and almost 100, respectively. Rate of spraying when grasses had 1 to 2 leaves did not affect numbers of grass plants but killed more tarweed than did spraying when grasses had 2 to 4 leaves.
    • Thermal Regulation of Water Uptake by Germinating Honey Mesquite Seeds

      Scifres, C. J.; Brock, J. H. (Society for Range Management, 1971-03-01)
      Ambient temperature regulated the rate and extent of water imbibition by germinating honey mesquite (Prosopis glandulosa Torr., var. glandulosa) seeds. Honey mesquite seeds required less water and less time for germination at 85 than at 100 or 70 F. Seeds at 70 F contained almost 3 times as much water as seeds at 85 F when germination first occurred although the rate of water uptake (mg/seed/hr) was reduced considerably. Decreasing moisture availability to 8 atm influenced the rate of water absorption by seeds more at 85 and 100 F than at 70 F.
    • Timing Use of Cool- and Warm-Season Grasses on Pine Ranges

      Pearson, H. A.; Mann, J. F.; Howard, D. A. (Society for Range Management, 1971-03-01)
      A 3-pasture rest-rotation grazing system based on plant growth and development during 2 annual precipitation periods resulted in more equitable utilization of cool- and warm-season grasses (Arizona fescue and mountain muhly) on ponderosa pine range. Plant and cattle productivity were maintained and utilization of forage species was more uniform./El presente estudio se llevó a cabo en un tipo de vegetación de pino ponderosa (Pinus ponderosa) cerca de Flagstaff, Arizona, E.U.A. Los pastos de esta zona se caracterizan por una mezcla de zacates de verano e invierno. Esto dificulta el pastoreo uniforme de las especies debido a la mezcla. Este estudio significó que con un sistema de rotación con tres potreros se obtuvo mas uniformidad de pastoreo de los diferentes zacates. Las épocas de pastoreo y descanso fueron conforme a las épocas de crecimiento relacionadas a las épocas de precipitación.