• Xeric big sagebrush, a new subspecies in the Artemisia tridentata complex

      Rosentreter, R.; Kelsey, R. G. (Society for Range Management, 1991-07-01)
      In 1970 a xeric form of mountain big sagebrush (Artemisia tridentata ssp. vaseyana (Rydb.) Beetle) was reported in west central Idaho. Observations of morphology, habitat, and ecology, and analyses of foliage chemical components, clearly indicate these plants represent a new subspecies (xericensis) in the big sagebrush complex. It grows at lower elevations, 762-1,524 m (2,500-5,000 ft) and drier environments, 305-560 mm (12-22 in) precipitation, than most mountain big sagebrush, and is found on basaitic foothill soils often in association with bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn. & Smith). In addition to soil type, the radiate growth form and a more branched paniculate inflorescence are 2 morphological characteristics useful in separating ssp. xericensis from ssp. vaseyana. It contains higher concentrations of crude protein (10.4%), phosphorus (0.3%), and total volatiles, and lower concentrations of tannins and total phenols than mountain big sagebrush. Distinct chromatograms were obtained for both subspecies when extracts were analyzed by gas and high performance liquid chromatography. Leaf morphology and fluorescence of leaf water extracts are useful characters for separating ssp. xericensis from ssp. tridentata. The chemical data, in combination with morphology and ecology, suggest this new subspecies was initially derived by hybridization of ssp. tridentata and ssp. vaseyana.
    • Vegetational response to short-duration and continuous grazing in southcentral New Mexico

      White, M. R.; Pieper, R. D.; Donart, G. B.; Trifaro, L. W. (Society for Range Management, 1991-07-01)
      Vegetational response of a nine-paddock, short-duration grazing cell was compared to that of a continuous pasture for a 5-year period in southcentral New Mexico. Differences in vegetational response to short-duration and continuous grazing on blue grama rangeland were small. Basal plant cover was slightly hither for the short-duration pastures, but end-of-season standing crop of all species was similar for both systems. Blue grama aboveground productivity and basal cover were higher for the short-duration pastures than for the continuously-grazed pasture. Possible short-term results from short-duration grazing include slightly higher stocking rates and a positive response of blue grama.
    • Variability in germination rate among seed lots of Lehmann lovegrass

      Hardegree, S. P.; Emmerich, W. E. (Society for Range Management, 1991-07-01)
      The regeneration success of Lehmann lovegrass (Eragrostis lehmanniana Nees) in southern Arizona may be partially due to rapid germination during sporadic periods of available soil moisture. There is limited information regarding germination rate of Lehmann lovegrass but it is known that total germination response for this species is highly variable. Some of this variability may result from differences in the degree of mechanical scarification during harvest, threshing, and storage. Scarified and nonscarified seed from 7 seed lots were germinated over the water potential range of 0 to -1.16 MPa. Results showed that mechanical scarification increased total germination and germination rate. Mechanical scarification reduced variability among seed lots for germination rate, but increased variability for total germination. The rapid germination hypothesis may be valid for Lehmann lovegrass as long as seed numbers are not limiting. Of the scarified seed that germinated above a water potential of -0.4 MPa, at least 10% did so between days 1 and 2 of the study.
    • Use of dry-weight rank multipliers for desert vegetation

      Mazaika, R.; Krausman, P. R. (Society for Range Management, 1991-07-01)
      The dry-weight rank technique has been used to measure vegetation in various habitats but has not been evaluated in desert shrub habitats. We sampled browse, forb, and grass in the palo-verde (Cercidium microphylum [Toff.] Rose and Johnston)-saguaro (Carnegiea gigantea [Engelm.) Britt and Rose) mountain slope vegetation association in the Sonoran Desert to determine if rank multipliers derived by 't Mannetje and Haydock differ from mean dry weights from different ranks. Previously derived multipliers were similar to those derived for mountain slope habitat.
    • Temperature profiles for germination of big sagebrush seeds from native stands

      Young, J. A.; Palmquist, D. E.; Evans, R. A. (Society for Range Management, 1991-07-01)
      The germination of seeds of big sagebrush (Artemisia tridentata, Nutt.) from 5 locations on the margin of the Carson Desert, Nevada, was studied over 5 growing seasons. Temperature profiles for germination were developed for seeds collected from each location. The profile consisted of 55 constant or alternating temperatures from 0 through 40 degrees C. Seed quality was high with optimum germination, defined as germination not different from the maximum observed at the 0.01 level of probability, averaging 80% for all years and all locations. Differences in germination parameters existed among locations, but not within locations among years of production. Differences among years of production were most pronounced at extreme incubation temperatures. The most frequent temperature regime supporting optimum germination of big sagebrush seeds was 15/20 degrees C (15 degrees C for 16 hours and 20 degrees C for 8 hours in each 24-hour cycle).
    • Technical Notes: Comparing the captec bolus to chromic oxide dosed twice daily using sheep in confinement

      Hatfield, P. G.; Walker, J. W.; Glimp, H. A. (Society for Range Management, 1991-07-01)
      Thirty-six wethers were used in 3 trials to compare estimates of fecal output using chromic oxide either in a continuous-release bolus or dosed twice daily. Wethers were confined in metabolism crates and fed alfalfa. Chromium content was determined in rectal grab samples. Only in trial 2 were differences (P = 0.06) detected between the ability of the 2 methods to precisely estimate fecal output. Variation of estimated fecal output was greater using the bolus than estimates using the twice daily dosing method. Both methods tended to over-estimate actual fecal output under pen fed conditions.
    • Surface runoff plot design for use in watershed research

      Williams, J. D.; Buckhouse, J. C. (Society for Range Management, 1991-07-01)
      A micro-watershed design is presented for use in watershed research projects. The plot size is 5 m (1 X 5 m) and uses low cost materials for construction. This plot size is suitable for surface flow and soil erosion research projects conducted where space is limiting and may be used either for monitoring natural or simulated rainfall events. Similar plots were used in research conducted on the Hall Ranch of the Eastern Oregon Agricultural Research Center, Union, Ore.
    • Statistical analyses for comparison of esophageal and hand-clipped samples from grazing trials

      Vogel, K. P.; Moore, K. J.; Johnson, B. E. (Society for Range Management, 1991-07-01)
      Esophageal fistulated animals are used to collect samples of the forage being consumed by animals in grazing experiments. Four principal hypotheses (H) can be tested in esophageal trials: (1) esophageal samples are similar over treatments, (2) available forage is similar over treatments, (3) esophageal and available forage samples are similar, and (4) differential selection of diet did not occur among treatments. Because of the constraints of limited animal numbers, multiple latin-square or crossover designs in which the same animals are used to sample pastures during different periods of time are used to test H 1. Available forage is determined by collecting samples from the pastures over the duration of the study. The experimental design for these samples is a split-plot in time which is used to test H 2. Analyses of 1 set of samples (esophageal or available) using the experimental design for the other set is inappropriate. Since esophageal and available samples are paired within experimental units, paired t-tests can be used to test H 3 by treatment or averaged over treatments. H 4 can be tested by conducting an analysis of variance of esophageal minus available (or vice-versa) differences averaged over periods. Significant treatment effects indicate differential selection of diet among treatments occurred.
    • Root morphological development in relation to shoot growth in seedlings of four range grasses

      Aguirre, L.; Johnson, D. A. (Society for Range Management, 1991-07-01)
      Successful seedling establishment in arid and semiarid rangelands depends on seedling root characteristics and on the relationship between shoot and root development. This study was conducted to determine seedling shoot and root developmental characteristics of 'Hycrest', a hybrid cultivar of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X Agropyron cristatum (L.) Gaert.]; 'Whitmar', a cultivar of bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Love subspecies inermis (Scrib. and Smith) Love]; 'Secar', a cultivar of Snake River wheatgrass [Elymus lanceolatus (Scribner & J.G. Smith) Gould]; and cheatgrass (Bromus tectorum L.) under favorable growth conditions. Seedlings were grown in 20-cm X 20-cm pots filled with sandy loam soil in a greenhouse and were destructively harvested 9, 17, 24, 31, 39, and 45 days after emergence. Cheatgrass had greater (P<0.05) plant height, leaf area, total shoot dry weight, primary root length, number and order of branching of the second group of seminal roots, order of branching of the first group of adventitious roots, and total root dry weight than Hycrest, Whitmar, and Secar. Hycrest had greater (P<0.05) seedling growth than Whitmar and Secar. The pattern of root and shoot development was similar in the 4 species; however, species differed in the cumulative growing degree days required to initiate elongation and branching of siminal and adventitious roots. The close association between the pattern of root development and shoot growth in the 4 species may be useful in deriving models of root morphological development based on shoot development.
    • Response of montane tall-forb communities to 2,4-D and mixtures of 2,4-D and picloram

      Murray, R. B.; Mayland, H. F.; Shewmaker, G. E. (Society for Range Management, 1991-07-01)
      Tall-forb communities occur an deep soils of the upper montane and subalpine zones of the Rocky Mountains and extend from southwestern Montana to southern Utah. In the Centennial Mountains of Montana, forbs comprise >80% of the annual yields, including 30-35% sticky geranium (Geranium viscosissimum) and 20-25% Potentilla spp. Tall-forb communities are rich in species diversity and very productive, but many of the forbs are not palatable to grazing ungulates. Suppression of the less palatable species, like sticky geranium, would increase the forage value for grazing. In 1983 and 1984 adjacent plots were sprayed during weeks 1, 2, 3, and 4 in July, with 2,4-D[(2,4 Dichlorophenoxy)acetic acid, isooctyl ester] applied at 1.1 or 2.2 kg 2,4-D/ha or 2.2 kg 2,4-D/ha plus 0.6 kg/ha of the potassium salt of picloram (4-amino-3,5,6-trichloropicolinic acid). Forage yields were measured in August of 1984, 85, and 86. Total forage yields ranged from 2,700 to 3,000 kg/ha on the untreated areas. Forb yields were significantly reduced, especially by the 2,4-D + picloram treatment. Herbicide treatments applied during flower-stalk development to first flower of sticky geranium were most effective. Grass and sedge production partially compensated for reductions in forb yields. Interseeding of introduced species into herbicide treated plots in 1993 was unsuccessful. Forb and grass production is expected to return to levels similar to those on untreated areas after 5 years.
    • Research observations: Standardized terminology for structures resulting in emergence and crown placement of 3 perennial grasses

      Ries, R. E.; Hofmann, L. (Society for Range Management, 1991-07-01)
      A significant problem we encountered in grass establishment research was confusion in the literature over seedling structures and terminology. From review of the historical literature and our observations of growth-chamber grown sideoats grama [Bouteloua curtipendula (Michx.) Torr.] western wheatgrass [Agropyron smithii Rydb.; new cytogenetic = Pascopyron smithii Rydb. (Loeve)l and smooth bromegrass (Bromus inermis Leyss.) seedlings, we suggest standard structures and terminology for grass seedlings. The nodes of a grass seedling are defined as the scutellar node, coleoptilar node, and leaf nodes named in sequence from first to last. The internode between the scutellar and coleoptilar nodes is termed the mesocotyl. The internode that develops inside the coleoptile between the coleoptilar and first leaf nodes is defined as the first leaf internode. Subsequent internodes are named for the leaf node immediately above; e.g., second leaf internode. Using these structures and terminology we found the "mechanism" of emergence for these grass seedlings from a 25-mm seeding depth was elongation of the mesocotyl (when expressed) and elongation of the coleoptile. Sideoats grama had a long mesocotyl and short coleoptile; western wheatgrass lacked or had a short mesocotyl and a long coleoptile; and smooth bromegrass had intermediate mesocotyl and coleoptile lengths. The "mechanism" of crown placement for seedlings that emerged and survived from a 51-mm seeding depth was non-elongation or elongation of the mesocotyl and leaf internodes. The crowns of sideoats grams seedlings were at the coleoptilar node, which was close to the soil surface. Western wheatgrass seedlings have their crowns near planting depth, usually at the coleoptilar node. Smooth bromegrass crowns were at variable depths because of variable elongation of the mesocotyl and leaf internodes.
    • Range condition analysis: Comparison of 2 methods in southern New Mexico desert grasslands

      Tedonkeng, E.; Pieper, R. D.; Beck, R. F. (Society for Range Management, 1991-07-01)
      Interest in evaluating theoretical considerations in traditional methods of determining range condition have increased recently with application of different analytical techniques. In this study, the traditional quantitative climax approach was compared to a cluster analysis method on range sites in desert grassland in southern New Mexico. Both methods identified 3 classes that corresponded to successional stages or range condition classes. The cluster analysis approach provided a more precise procedure than the quantitative climax approach, as evaluated by multiple discriminate analysis. However, the cluster analysis is a much more complex analytical procedure than the quantitative climax approach, and may be limited for management purposes.
    • Prescribed grazing as a secondary impact in a western riparian floodplain

      Sedgwick, J. A.; Knopf, F. L. (Society for Range Management, 1991-07-01)
      The effect of late-autumn cattle grazing on plant biomass was examined in a western Great Plains cottonwood riparian zone prone to catastrophic flooding every 5-8 years. Following 1 year of pre-treatment data collection in 1982, five 16-ha pastures were grazed from 1982 to 1984 and compared to 5 control pastures within the South Platte River floodplain in northeastern Colorado. At a prescribed grazing level of 0.46 ha/AUM, riparian vegetation proved to be resilient to the impacts of grazing. We detected only a few significant treatment effects for above-ground biomass after succeeding growing seasons. Willows (Salix spp.) responded negatively to grazing whereas biomass of prairie cordgrass (Spartina pectinata Link) was greater on grazed plots. Yearly changes in above-ground biomass, especially dramatic following a severe flood in 1983, suggest that periodic, catastrophic flooding is a major perturbation to the ecosystem, and in conjunction with our results on grazing impacts, indicate that dormant-season grazing within Soil Conservation Service (SCS) guidelines is a comparatively minor impact within the floodplain. In addition, grazing impacts were probably further mitigated by a major forage supplement of cottonwood leaves which was available at the time of cattle introductions. This local forage supplement ultimately created a lighter grazing treatment than that originally prescribed.
    • Physiological responses of 6 wheatgrass cultivars to mycorrhizae

      Jun, D. J.; Allen, E. B. (Society for Range Management, 1991-07-01)
      The physiological and morphological responses of 6 wheatgrass (Agropyron) cultivars to vesicular-arbuscular mycorrhizal inoculation were measured in the greenhouse. These included diploid, tetraploid, and hexaploid cultivars. Plants had up to 94% infection after 4 months. The 2 diploid cultivars (A. cristatum cv.'Fairway' and A. cristatum ssp. puberulum) formed infection most rapidly, and they also had significantly reduced root biomass and higher water use efficiency with infection. A hexaploid cultivar (A. cristatum from U.S.S.R.) produced significantly more tillers with inoculation, while the tetraploid A. desertorum cv. 'Nordan' had fewer tillers and wider leaves. Inoculation increased leaf phosphorus concentration in 4 of the 6 cultivars. Carbon dioxide gas exchange rate, transpiration rate, stomatal resistance, and N concentration were not significantly affected by mycorrhizal inoculation for any of the cultivars. The cultivar Nordan had the greatest number of physiological and morphological increases in response to mycorrhizal infection, while A. cristatum from Iran (hexaploid) performed most poorly in that it had reduced WUE and no apparent beneficial responses to infection. There was no relationship between ploidy level and mycorrhizal response.
    • Nutritional value of fresh Gambel oak browse for Spanish goats

      Dick, B. L.; Urness, P. J. (Society for Range Management, 1991-07-01)
      Little information is available on the nutritional value of fresh browse for ruminants. This study examined the nutritive value of Gambel oak (Quercus gambelii Nutt.) for Spanish goats. Fresh Gambel oak browse was harvested at 2 phenological stages and mixed with chopped alfalfa hay to formulate 6 diets, varying in oak content. Diets included 95% juvenile oak/5% alfalfa (95J), 80% juvenile oak/20% alfalfa (80J), 65% juvenile oak/35% alfalfa (65J), 80% mature oak/20% alfalfa (80M), 40% mature oak/60% alfalfa (40M), and an alfalfa control (ALF). Diets were evaluated for goats using a series of digestion-balance trials, in a completely randomized design. Dry matter intake was highest (P < 0.01) for animals on diets with mature oak (80M-37.8, 40M-34.5 grams kg-1 day-1, and lowest on diets containing juvenile oak (95J-23.6, 80J-31.6, 65J-29.9 grams kg-1 day-1). Digestibility of dry matter and cell wall components was lower (P < 0.01) for mature oak diets, and higher for juvenile oak diets. Digestibility coefficients for dry matter were as follows: (80M-57.8%, 40M-58.8%, 95J-68.6%, 80J-65.3%, 65J-66.3%. Digestibility coefficients for cell wall were: 80M-33.1%, 40M-37.4%, 95J-53.7%, 80J-45.8%, 65J-47.3%. All diets provided nitrogen and energy in excess of maintenance requirements, as reflected by weight gains for all animals in every trial. Fecal and urinary nitrogen losses did not appear to be related to tannin content of the diets, since juvenile oak diets resulted in reduced nitrogen outputs, presumably due to reduced nitrogen intakes for these diets. We conclude that Gambel oak, even juvenile material in high dietary percentages (95%), provides adequate nutrients and should be considered a valuable forage for goats in oakbrush habitats.
    • Multiple use of public rangeland: Antelope and stocker cattle in Wyoming

      Bastian, C. T.; Jacobs, J. J.; Held, L. J.; Smith, M. A. (Society for Range Management, 1991-07-01)
      The government must manage public rangeland in the face of alternative multiple use interests, including wildlife and domestic livestock production. The objectives of this study were to estimate a production possibilities frontier for antelope (Antilocapra americana (Ord)) and stocker cattle on the Wyoming Red Desert and then evaluate the most economical combination for the specific production and price assumptions used in the analysis. Nine antelope-steer combinations were derived by using a linear programming model to maximize total number of animals subject to annual forage production on a representative 405-ha range site. The resulting 9 combinations included 72 head of antelope with no steers at one extreme and 35 head of stocker steers with no antelope at the other extreme, with various combinations of each in between. Because of the different forage preferences of antelope (primarily browse) and cattle (primarily grass), the marginal rates of substitution of cattle for antelope varied widely along the production possibilities frontier. Specifically, the marginal rate of substitution of cattle for antelope was very low moving from 72 antelope-0 steers, to 69 antelope-29 steers, in terms of sacrificing only a few antelope (3) in exchange for a comparatively large number of steers (29). Conversely, the marginal rate of substitution of cattle for antelope moving from 69 antelope-29 steers, to 0 antelope-35 steers was very high in terms of sacrificing a relatively large number of antelope (69) in exchange for only a few additional steers (6). This wide range of substitution rates suggests that economic benefits from antelope and cattle would have to be extremely different before "multiple use" is not preferred in the case study setting.
    • Lesser prairie-chicken densities on tebuthiuron-treated and untreated sand shinnery oak rangelands

      Olawsky, C. D.; Smith, L. M. (Society for Range Management, 1991-07-01)
      Line transect procedures were used to estimate density of lesser prairie-chicken (Tympanuchus pallidicinctus) in tebuthiuron-treated and untreated sand shinnery oak (Quercus havardii Rydb.) rangelands. Forb and grass composition was greater (P less than or equal to 0.014, P < 0.001, respectively) in treated areas than in untreated areas, while shrub composition was greater (P < 0.001) in untreated sites. Densities of lesser prairie-chicken were similar (P less than or equal to 0.298) between treatments. Summer densities were 0.26 birds/ha in treated areas and 0.20 birds/ha in untreated areas, while winter densities were 0.53 and 0.34 birds/ha, respectively. Because shinnery oak provides an important source of shade and food for lesser prairie-chicken, and may be important for cover maintenance by preventing entire areas from being overgrazed in dry years, preservation of some untreated areas is recommended.
    • Influence of temperature and cheatgrass competition on seedling development of two bunchgrasses

      Aguirre, L.; Johnson, D. A. (Society for Range Management, 1991-07-01)
      Rapid seedling growth and ability to compete against cheatgrass (Bromus tectorum L.) are 2 characteristics that perennial grasses must have for successful establishment on semiarid western rangelands. This study was conducted to determine the effects of temperature and competition from cheatgrass on seedling root and shoot growth of 'Hycrest' crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaert.] and 'Whitmar' bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) Loeve). For the temperature study, seedlings were grown in growth chambers with alternate 12-h day/night temperatures of 10/5, 15/5, and 20/5 degrees C. Seedlings were destructively harvested on 6 dates and evaluated for 14 root and shoot characteristics. Leaf development, leaf area, total root length, and number and length of the second group of seminal roots were greater (P < 0.05) for cheatgrass than Hycrest and Whitmar at all dates and temperatures. Cheatgrass elongated adventitious roots earlier and at colder temperatures (10/5 degrees C) than Hycrest, and Whitmar did not produce adventitious roots at low temperatures. This would favor the establishment of cheatgrass at low temperatures. For the competition study, seedlings were established in pots in a greenhouse with planting ratios of Hycrest to cheatgrass and Whitmar to cheatgrass of 1:0, 2:0, and 5:0 (32, 64, and 159 plants m-2 respectively) and compared with planting ratios of 1:1 and 1:4. Fourteen shoot and root characteristics were evaluated 15, 30, and 50 days after seedling emergence. Hycrest had greater shoot and root development than Whitmar for all seedling characteristics. Competition from cheatgrass reduced growth of Hycrest and Whitmar seedlings. At a planting ratio of 1:4, Hycrest-cheatgrass mixtures depleted soil moisture to lower soil water potentials than Whitmar-cheatgrass mixtures. These results indicate that Hycrest seedlings are more effective competitors with cheatgrass than Whitmar seedlings.
    • Forage production of reclaimed mined lands as influenced by nitrogen fertilization and mulching practice

      Schuman, G. E.; Taylor, E. M.; Rauzi, F. (Society for Range Management, 1991-07-01)
      Fertilizer nitrogen (N) management and other cultural practices used in reclamation can have a significant effect on the successful revegetation of mined lands. Repeated fertilization of revegetated lands creates management and economic concerns. Nitrogen fertilizer was broadcast at 67 kg ha-1 yr-1 for 4 years and at 268 ha-1 for 1 year on revegetated mined land to evaluate N management effects on forage production. Seeded grass production over 5 years did not exhibit consistent increases for the single N fertilizer application compared to the 4 annual applications. Although the single, higher N fertilization treatment only produced significantly greater forage in 3 instances compared to the lower annual fertilization treatment, it would result in a significant savings in application costs. Seeded grass production was higher and annual forb production lower when established using a standing grain stubble mulch compared to a crimped straw mulch. A single, higher application rate of nitrogen and a stubble mulch are recommended because of their production, management, and economic benefits.