Now showing items 8623-8642 of 20719

    • Growth Reactions of Sub-Alpine Norway Spruce (Picea Abies (L.) Karst) Following One-Sided Light Exposure (Case Study at Davos "Lusiwald")

      Bräker, Otto U.; Baumann, Ernst; Swiss Federal Research Institute WSL, Birmensdorf, Switzerland (Tree-Ring Society, 2006)
      In 1982, several rectangular openings were cut in a 100 year old sub-alpine Norway spruce forest stand to initiate regeneration at the Lusiwald site at Davos, Switzerland. The openings on the steep, north-facing slope created rapid changes to the environment of the border trees. Growth reactions of these border trees were compared and analysed with reference trees from the adjacent closed canopy stand in 1997. The radial growth pattern of the two data sets differed within the 14-year period since the openings were cut; the border trees showed growth releases. The growth reaction at the stem base was larger than at breast height. Changes in wind exposure may have influenced border trees to adapt their root systems. Sub-alpine Norway spruce stands aged around 100 years, which are usually considered slow-growing on a north aspect, still seem capable of reacting to greater resource availability such as sudden light changes.
    • Growth Regulator Herbicides Prevent Invasive Annual Grass Seed Production Under Field Conditions

      Rinella, Matthew J.; Masters, Robert A.; Bellows, Susan E. (Society for Range Management, 2010-07-01)
      Growth regulator herbicides, such as 2,4-D, dicamba, picloram, and aminopyralid, are commonly used to control broadleaf weeds in rangelands, noncroplands, and cereal crops. If applied to cereals at late growth stages, while the grasses are developing reproductive parts, the herbicides often reduce cereal seed production. We are researching methods for using this injury response to control invasive annual grasses in rangelands by depleting their short-lived seed banks. In a previous greenhouse study, we found picloram and dicamba reduced seed production of the invasive annual grass Japanese brome (Bromus japonicus Thunb.) by nearly 100%. However, this promising greenhouse finding needs to be corroborated in the field before growth regulators can be confidently recommended for invasive annual grass control. This research note describes a study conducted in eastern Montana suggesting growth regulators may provide excellent control of invasive annual grasses. Specifically, we found typical use rates of aminopyralid and picloram reduced Japanese brome seed production by more than 95% (based on sample means) when applied at three different plant growth stages. This promising result contributes to the accumulating body of evidence suggesting growth regulators may control invasive annual grasses. 
    • Growth regulators' effect on crested wheatgrass forage yield and quality

      White, L. M. (Society for Range Management, 1989-01-01)
      If crested wheatgrass [Agropyron desertorum (Fisch.) Schult.] could be maintained in an immature growth stage, it would improve forage quality and thus extend the grazing season. In 1981 and 1982, plant growth regulators were applied to crested wheatgrass 0, 2, 4, and 6 weeks after first floral primordium initiation to determine which compound, date, and rate of application would maximize forage quality yet minimize reduction of forage yield when harvested at seed ripe stage. Mefluidide [N-(2,4-dimethyl-5-{[(trifluoromethyl)-sulfonyl]amino}phenyl)acetamide] at 4 rates [0.0, 0.28, 0.56, and 0.84 kg/ha active ingredient (a.i.)], maleic hydrazide (MH) (1,2-dihydro-3,6-pyridazinedione) at 4.5 kg/ha a.i., and MH (3.36kg/ha a.i.) plus chlorflurenol (methyl-2-chloro-9-hydroxyfluorene-9-carboxylate) at 1.12 kg/ha a.i. were applied to crested wheatgrass growing on a Shambo loam (Typic Haploborolls) in northeast Montana. Application of MH or MH plus chlorflurenol generally gave a similar response in heading, forage yield, CP, and in vitro organic matter digestibility on a dry matter basis (IVDOMD) as did melfluidide at 0.56 kg/ha. Mefluidide (0.56 kg/ha) applied 2 weeks after first floral primordium initiation decreased heading 80 and 95%, decreased forage yield 20 and 30%, increased CP 1.7 and 2.3 percentage units, and increased IVDOMD 1.8 to 4.2 percentage units compared to untreated, depending upon year.
    • Growth response of Mediterranean herbaceous swards to inoculation with Azospirillum brasilense

      Zaady, E.; Okon, Y.; Perevolotsky, A. (Society for Range Management, 1994-01-01)
      A study was conducted on the effect of the rhizobacterium Azospirillum brasilense strain Cd on the production of herbaceous swards growing at 2 rangeland habitats in Israel. One habitat was the semiarid zone (< 300 mm annual rainfall, calcareous soil on rocky slopes) while the other was a typical Mediterranean zone (approximately-600 mm annual rainfall, karstic rock covered with terra rossa soil). The inoculum was applied in water suspension at a concentration of 109 colony forming units (CFU) ml-1. The effect of inoculation was compared with P-fertilizer application at a rate of 5 g/m2. The same treatments were also applied on potted soil from the 2 sites. The semiarid ecosystem showed a strong response to Azospirillum inoculation, to P-fertilizer and to the combination of these 2 treatments, with aerial biomass production increasing by approximately fourfold in the treatments as compared with the control. The response to inoculation or P-fertilization was similar, with no interaction or additive effect noted for the combined treatment. At the Mediterranean site, the response to inoculation or P-fertilization alone was variable, with only a moderate effect on biomass production as compared with the control; however, the inoculation-fertilization interaction was highly significant and doubled biomass production. In the greenhouse experiment, the response to inoculation or fertilization was significant and the biomass production at the end of the growing season was approximately 50% higher than in the control. At both sites, standing biomass was greater in the treated plots already at early stages of growth, thereby potentially lengthening the effective grazing season. It is suggested that inoculation with Azospirillum brasilense on a commercial scale may offer a means of increasing rangeland production without resorting to costly and ecologically unfavorable fertilizer application.
    • Growth Response of Two Saltbush Species to Nitrate, Ammonium and Urea Nitrogen Added to Processed Oil Shale

      Richardson, S. G.; McKell, C. M. (Society for Range Management, 1982-01-01)
      Nitrate nitrogen promoted good growth of cuneate saltbush (Atriplex cuneata) and gardner saltbush (A. gardneri) on processed oil shale in a glasshouse pot experiment, but ammonium and urea nitrogen were not utilized effectively in growth.
    • Growth Response of Two Saltbush Species to Nitrate, Ammonium, and Urea Nitrogen Added to Processed Oil Shale

      Richardson, S. G.; McKell, C. M. (Society for Range Management, 1981-09-01)
      Nitrate nitrogen promoted good growth of cuneate saltbush (Atriplex cuneata) and gardner saltbush (A. gardneri) on processed oil shale in a glasshouse pot experiment but ammonium and urea nitrogen were not utilized effectively in growth.
    • Growth responses of warm-season tallgrasses to dormant-season management

      Schacht, W. H.; Smart, A. J.; Anderson, B. E.; Moser, L. E.; Rasby, R. (Society for Range Management, 1998-07-01)
      A study on Conservation Reserve Program (CRP) land was established in southeastern Nebraska to determine the effect of dormant-season management on subsequent-year growth rates and yields of tallgrasses. The purpose of the management practices was removal of standing dead material and litter that negatively impact plant growth and grazing efficiency. Treatments consisted of a control with no residue manipulation and 5 residue manipulation practices including (1) October shredding and leaving residue; (2) October haying; (3) October intensive grazing; (4) March intensive grazing; and (5) spring prescribed burning. The study was conducted in 1994/95 and 1995/96 on a switchgrass (Panicum virgatum L.) monoculture and mixed stand of warm-season tallgrasses dominated by big bluestem (Andropogon gerardii Vitman) and little bluestem [Schizachyrium scoparium (Michx.) Nash]. The manipulation treatments effectively removed standing dead material without reducing yields in the growing season following application. Marked switchgrass tillers on the control plots increased (P < 0.1) in height at a more rapid rate than switchgrass on other treatments until late summer in both years. Rate of morphological development was similar (P > 0.1) for all treatments in 1995 and 1996. Rate of height increase and morphological development in big and little bluestem on the mixed grass site generally was comparable or slower on the manipulation treatments than the control in both years; however, big and little bluestem tillers grew relatively rapidly at the end of the 1995 growing season. Because the manipulation treatments generally did not increase tiller growth rates of the dominant grass species, potential harvest dates would be similar to those of untreated areas.
    • Growth Rings of Sagebrush Reveal Rainfall Records

      Ferguson, C. W.; Humphrey, R. R.; Department of Watershed Management; Department of Watershed Management (College of Agriculture, University of Arizona (Tucson, AZ), 1959)
    • Growth, ion accumulation, and nitrogen fractioning in Atriplex barclayana grown at various salinities

      Nerd, A.; Pasternak, D. (Society for Range Management, 1992-03-01)
      Effects of varying NaCl levels (50-400 mol/m3) on growth, ion accumulation, and nitrogen fractioning in Atriplex barclayana were studied in a greenhouse experiment using a water culture method. Relative growth rate of shoots was maintained at a high constant level at NaCl concentrations not exceeding 200 mol/m3, but fell to less than half when salt concentration was increased to 400 mol/m3. Potassium and calcium concentrations in shoots were unaffected by root media salinities up to a concentration of 200 mol/m3 but declined at 400 mol/m3. Sodium and chloride concentrations in shoots demonstrated an increase with rising salinity, particularly when NaCl level was increased from 50 to 100 mol/m3. Total nitrogen concentration in leaves was relatively high (3.51-3.72% of dw) at salinities between 50 to 200 mol/m3 NaCl but decreased significantly at 400 mol/m3 NaCl. Glycinebetaine in leaves rose slightly when culture salinity was raised from 50 to 100 mol/m3 NaCl and then remained constant up to an NaCl level of 400 mol/m3. Our results indicate that A. barclayana is a highly salt-tolerant plant with leaves rich in nitrogen, but high salt concentrations in the leaves and stems even at low salinities markedly reduce its potential as a fodder plant.
    • Growth, Productivity and Chemical Composition of a Sub-Alpine Meadow in Interior British Columbia

      McLean, A.; Nicholson, H. H.; van Ryswyk, A. L. (Society for Range Management, 1963-09-01)
    • Growth-climate relationships of Pinus strobusin the floodway versus terrace forest along the banks of the Red Cedar River, Michigan

      Chhin, S.; Chumack, K.; Dahl, T.A.; David, E.T.; Kurzeja, P.; Magruder, M.; Telewski, F.W. (Tree-Ring Society, 2013-07)
      We examined the effects of climate (i.e. temperature, precipitation, moisture index, river discharge) on the radial growth of eastern white pine (Pinus strobus) in two contrasting microhabitats (floodway versus terrace) in relation to an elevational and moisture gradient along the banks of the Red Cedar River, Michigan. We hypothesized that trees growing on the terrace sites would have a greater sensitivity to climatic factors than trees growing in the floodway. Increment cores were sampled and crossdated from dominant and co-dominant trees in the floodway and terrace sites and standardized growth chronologies were developed. Mean sensitivity, standard deviation, percentage of absent rings, and intertree correlation were generally greater for eastern white pine on the terrace compared to the floodway forests. Dendroclimatic relationships were examined with bootstrapped correlation analysis, which indicated that radial growth of eastern white pine in both floodway and terrace sites was negatively associated with summer temperature (i.e. June and July) of the current growing season. Radial growth in both floodway and terrace sites were positively related to current May precipitation, moisture index, and river discharge. Dendroclimatic response of eastern white pine in floodway and terrace sites differed in that the effect of summer moisture stress was more persistent in the terrace sites into later summer (i.e. current July ) whereas floodway sites showed a negative response to prior-year May precipitation and moisture index. Although precipitation and hydrological conditions of the river were generally favorable during the summer months, which appeared to have promoted soil moisture recharge, flooding in early winter (i.e. prior November) had a negative impact on growth in both microhabitats. The effect of winter river discharge was significantly negative in January (t) in the floodway sites compared to the terrace sites.
    • Growth-Ring Research in Norway

      Høeg, O. A. (Tree-Ring Society, 1956-04)
    • Guar Shows Potential as Drought-Tolerant Summer Crop for Arizona Grain Farmers

      Dennis, Robert; Webster, Guy; Arizona Extension Agronomist; Extension Editor (College of Agriculture, University of Arizona (Tucson, AZ), 1979)
    • Guarding Against Invaders: Remote Sensing on the Range

      Boswell, Evelyn (Society for Range Management, 2000-08-01)
    • Guarding Sheep: It's a Dog's World

      Bilodeaux, Jean (Society for Range Management, 1993-02-01)
    • Guayule, Jojoba, Buffalo Gourd and Russian Thistle: Plant Characteristics, Products and Commercialization Potential

      Foster, Kennith E.; Karpiscak, Martin M.; Taylor, Jonathan G.; Wright, N. Gene; Office of Arid Lands Studies, University of Arizona (University of Arizona (Tucson, AZ), 1983)
    • Guayule: A Rangeland Source of Natural Rubber

      Foster, M. A.; Moore, Jaroy (Society for Range Management, 1987-06-01)
    • Guide a Range Curriculum with an Educational Needs Assessment

      Norton, B. E.; Eastmond, J. N. (Society for Range Management, 1981-11-01)
      This study, undertaken as a cooperative effort between the Utah State University Range Science Department and the Instructional Development office, surveyed 138 alumni of the department to assist in the identification of needs for curriculum improvement. Strong support for the following educational concerns was evident: (1) a practical and pragmatic emphasis in the curriculum, including focus upon political and economic aspects of range management; (2) an emphasis upon communication skills, particularly oral communication, and dealing with "people problems"; (3) a field component to complement the classroom wherever possible. Findings from the study have led to the revision of two courses, the beginning of two others, and have endorsed a core course on land management policy recently introduced into the College of Natural Resources. The results of the survey have assisted curriculum development in the Range Science Department at Utah State University and may prove helpful for other educators in the field.
    • Guidelines for Grazing Sheep on Rangelands Used by Big Game in Winter

      Jensen, C. H.; Smith, A. D.; Scotter, G. W. (Society for Range Management, 1972-09-01)
      A big game winter range in northen Utah was grazed with domestic sheep to ascertain what seasons and intensity of use would maximize utilization of herbs and minimize utilization of shrubs which provide the majority of forage for big game in winter, thus minimizing forage competition between big game and sheep. In late spring and early summer sheep ate mostly herbs. The light utilization of shrubs resulted in little or no reduction in forage production by shrubs at the end of the growing season. After mid-July, sheep heavily utilized bitterbrush (Purshia tridentata), the most desirable and abundant shrub for big game in this area. Grazing after mid-July reduced the volume of bitterbrush forage available for big game proportionately to the percentage utilization observed. There was no evidence that subsequent annual productivity of established plants was impaired by any of the grazing systems imposed.