Now showing items 12473-12492 of 20709

    • Oak (Quercus spp.) Sprouts Growth Rates on a Central Oklahoma Shallow Savannah Range Site

      Powell, J.; Lowry, D. P. (Society for Range Management, 1980-07-01)
    • An Oak Chronology for South Central Scotland

      Baillie, Michael G. L.; Palaeoecology Laboratory, Queen's University, Belfast (Tree-Ring Society, 1977)
      The chronology presented was constructed in the hope of answering two specific questions. It was intended to assess the potential of dendrochronology in an area where no previous investigations had taken place. In addition it was necessary as a step towards assessing the cross agreements between different areas within the British Isles. The resulting 1030 year chronology has shown the potential usefulness of the method in Scotland and allowed the suggestion of larger tree -ring areas within the British Isles than have previously been supposed.
    • Oak Consumption by Cattle in Arizona

      Ruyle, G. B.; Grumbles, R. L.; Murphy, M. J.; Cline, R. C. (Society for Range Management, 1986-06-01)
    • Oak Ridge Associated Universities Radiocarbon Dates II

      Noakes, John E.; Kim, S. M.; Fischer, F. (American Journal of Science, 1968-01-01)
    • Oak Ridge Institute of Nuclear Studies Radiocarbon Dates I

      Noakes, John E.; Kim, S. M.; Akers, L. K. (American Journal of Science, 1967-01-01)
    • Oak seedling establishment on California rangelands

      Adams, T. E.; Sands, P. B.; Weitkamp, W. H.; McDougald, N. K. (Society for Range Management, 1992-01-01)
      Factors responsible for poor recruitment of blue oak (Quercus douglasii H. & A.) and valley oak (Q. lobata Nee) need to be determined on California hardwood rangelands so that management strategies for enhancement of recruitment can be developed. To examine selected factors, exclusive of large herbivore impacts, a series of acorn seeding experiments was initiated in 1985 in 6 counties on representative sites. At each site, the experimental treatments were the factorial combination of herbs vs. no herbs and screen protection vs. no protection. The experimental design was 4 randomized complete blocks of the herb treatments with each main plot split for the 2 levels of protection. Rainfall and edaphic factors were used to help interpret measures of seedling emergence, survival, and growth. Herbaceous plant control for reduction of moisture stress was the most important factor examined. Emergence was significantly improved by control in nearly 80% of blue oak seedings and in 33% of valley oak seedings. Average first year survival, expressed as a percent of acorns sown, was significantly improved with control in seedings of both blue oak (33% vs. 18%) and valley oak (45% vs. 21%). Limited data suggest the difference in survival remains consistent over time as overall survival declines. With few exceptions, the addition of screen protection discouraged predation and significantly enhanced survival and growth. Window screen cages also may have contributed an unmeasured shade effect.
    • Oats For Winter Forage Production

      Thompson, R. K.; Day, A. D.; Mesa Branch Experiment Station; Department of Agronomy (College of Agriculture, University of Arizona (Tucson, AZ), 1960)
    • Obituary (Paul Damon, 1921-2005)

      Jull, A. J. Timothy; Barbetti, Mike; Haynes, Vance (Department of Geosciences, The University of Arizona, 2005-01-01)
    • Obituary: Austin Long

      Eastoe, C.; Leavitt, S.; Tanner Elliott, K.; Sewell, D. (Department of Geosciences, The University of Arizona, 2010-01-01)
    • Obituary: Grant Kocharov

      Dergachev, Valentin; Ostrykov, Valery; Gladysheva, Olga; Koudriavtsev, Igor; Ogurtsov, Maxim; Dreschoff, Gisela; Jungner, Högne (Department of Geosciences, The University of Arizona, 2008-01-01)
    • Obituary: Jacques Labeyrie (1920–2011)

      Paterne, Martine (Department of Geosciences, The University of Arizona, 2011-09-16)
    • Obituary: Jean-François Saliège (1943–2012)

      Zazzo, Antoine (Department of Geosciences, The University of Arizona, 2012-10-15)
    • Obituary: Johann Carl Vogel (1932-2012)

      Talma, Siep; Visser, Ebbie; Fuls, Annemarie; Mook, Wim; van der Plicht, Hans (Department of Geosciences, The University of Arizona, 2012-05-04)
    • Obituary: Leopold Dmitrievich Sulerzhitsky (1929-2012)

      Pokrovsky, B. G.; Pevzner, M. M.; Zaretskaya, N. E.; Kuzmin, Y.; Ineshin, E. (Department of Geosciences, The University of Arizona, 2012-05-04)
    • An Objective Method to Identify Missing or False Rings

      Wendland, Wayne M.; Center for Climatic Research, The University of Wisconsin (Tree-Ring Society, 1975)
    • Objectives and Methods in New England Tree-Ring Studies

      Lyon, Charles J. (Tree-Ring Society, 1939-04)
    • Observation on cattle liveweight changes and fecal indices in Sudan

      Hasham, I. M.; Fadlalla, B. (Society for Range Management, 1989-03-01)
      Changes in liveweight of sedentary and migratory herds of cattle in south Kordofan Province, Sudan, were determined monthly. Feces of these animals were analyzed for N and ADF during the same period. Both the sedentary and the migratory herds gained liveweights during periods August to September and November to February and lost liveweight during October and from March to July. Changes in liveweights were more highly related to fecal ADF concentrations (r = -0.60, P<0.002) than to fecal N concentrations (r = -0.085, P<0.305).
    • Observation: Botanical and other characteristics in Arctic salt-affected coastal areas

      Bruce, L. B.; Panciera, M. T.; Gavlak, R. G.; Tilman, B. A.; Cadle, J. M. (Society for Range Management, 1995-05-01)
      This study was designed to provide information on cover, botanical composition, and frequency of major plant species in a brood-rearing area used by migratory geese south of Howe Island on the Sagavanirktok River Delta near Prudhoe Bay, Alaska. The area is split by the Endicott road and the information was also used to gain preliminary information concerning the effect of the road on goose and caribou activity. Transects on the east and west sides of the access road at the base of the Endicott causeway were established to evaluate occurrences of vegetation, goose fecal pellets, caribou tracks, and coastal debris. The point intercept method characterized plant cover, species frequency, and botanical composition. The recorded occurrence of fecal pellets and tracks on the transects were used as estimates of the presence of geese and caribou. Vegetative cover was 21% west and 38% east of the road near the Endicott causeway base in 1991. The 3 species most prominent west of the road were Carex sub-spathacea Wormsk., Salix spp., and Puccinellia phryganodes (Trin.) Scribn. & Merr. (botanical composition of 26, 23, and 21%, respectively). East of the road, Salix spp. (43%) dominated botanical composition followed by Carex aquatilis Wahlenb. (13%) and Dryas integrifolia M. Vahl (11%). The west and east sides differed botanically. Caribou tracks were observed in 60% of the transects on both sides of the road and goose fecal pellets were more prevalent on the west side (86%) than on the east side (48%). Geese pellets and caribou tracks occurred in different locations in the study area. Goose fecal pellets were from all goose species and may have included more than 1 year.
    • Observation: Cattle diets on excellent and good condition Chihuahuan desert rangelands

      Smith, G.; Holechek, J. L.; Cardenas, M. (Society for Range Management, 1994-09-01)
      Information is limited on the influence of range condition on cattle diets in the Chihuahuan desert. Botanical composition of cattle diets on Chihuahuan desert ranges in excellent and good condition was studied by microhistological analysis. Cattle feces were analyzed seasonally from fall 1991 through fall 1992. Excellent condition and good condition ranges supported 86% and 72% of the climax vegetation, respectively. Key species in cattle diets on the excellent condition range were black grama (Bouteloua eripoda Torr.) and threeawns (Aristida spp.). On the good condition range the key species were dropseeds (Sporobolus spp.), threeawns and black grama. Total grass and black grama content of cattle diets were greater on the excellent condition range. Seasonal trends occurred in cattle diets on good condition but not on excellent condition range. Low availability of forbs and shrubs explained the high diets similarities among seasons on the excellent condition range. Cattle on good condition range readily used forbs and shrubs when green grass was unavailable. Nitrogen and phosphorus analyses of fecal samples indicated diets were nutritionally superior on the good compared to the excellent condition range. Our research and other studies show consumption of forbs and shrubs permits cattle to maximize their nutritional welfare when grasses are dormant. The excellent condition range in our study had a different(P<0.05) mean grass standing crop (999 kg/ha) across periods compared to on the good condition range (659 kg/ha). Based on our research and other studies excellent condition Chihuahuan desert range maximizes forage quantity for cattle but good condition range appears better from a nutritional standpoint in the spring and early summer. Our research and other studies indicate Chihuahuan desert ranges dominated by black grama are most effectively used in winter while ranges with a high dropseed component are best suited for use in summer and early fall.