• Effect of water on morphological development in seedlings of three range grasses: Root branching patterns

      Johnson, D. A.; Aguirre, L. (Society for Range Management, 1991-07-01)
      Root morphology is important for successful seedling establishment and survival on semiarid rangelands. This study was conducted to determine the response of early seedling root morphological development of 'Hycrest' [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaert.], 'Whitmar' [Pseudoroegneria spicata (Pursh) Loeve], and cheatgrass (Bromus tectorum L.) to water. A greenhouse line-source sprinkler system provided a gradient of water application (77, 66, 37, and 5 ml/day). Root morphology was examined at 15, 30, and 45 days after seedling emergence. Order of branching of roots associated with the first foliar node was greater in cheatgrass than in Hycrest or Whitmar at all water applications and dates. Length of the primary root, length of the second group of seminal roots, and length of the first group of adventitious roots were similar in cheatgrass and Hycrest. Root branching for the 3 species decreased as less water was applied, except for cheatgrass irrigated with 5 ml/day. The ability of cheatgrass seedlings to grow with little water was related to their greater order of branching of seminal roots, branching density on the main axis, and length of lateral roots and external-external links. The greater root branching densities, lateral root lengths, and external-external link lengths enabled Hycrest seedlings to grow better than Whitmar seedlings with little water. These root morphological characteristics may prove useful in improving seedling establishment of perennial range grasses.
    • Effects of established perennial grasses on yields of associated annual weeds

      Borman, M. M.; Krueger, W. C.; Johnson, D. E. (Society for Range Management, 1991-07-01)
      Perennial grasses are needed for seeding annual grasslands in the Mediterranean/maritime climatic regime of southwest Oregon. Selection of plants for reseeding purposes would be facilitated by identification of perennial grasses that, once established, are able to suppress resident annual plant production. Perennial grasses were transplanted and allowed to establish in the absence of competition for the first growing season at 2 sites in the foothills of southwest Oregon. After the first growing season, resident annual plants were allowed to reinvade. Perennial grasses such as Berber orchardgrass (Dactylis glomerata L. var. Berber) and Idaho fescue (Festuca idahoensis Elmer) that begin growth early suppressed annuals more effectively than later growing perennial grasses such as intermediate and tall wheatgrasses (Agropyron intermedium (Host.) Beauv. and A. elongatum (Host.) Beauv., respectively). Of the perennial grasses adapted to these sites, those which initiated growth earliest, maintained some growth through winter months, and matured earliest were the best competitors.
    • Effects of single season and rotation harvesting on cool- and warm-season grasses of a mountain grassland

      Jameson, D. A. (Society for Range Management, 1991-07-01)
      A mountain bunchgrass community with cool-season Parry oatgrass (Danthonia parryi) and warm-season slimstem muhly (Muhlenbergia filiculmis) as major grasses was treated with early partial harvest of cool-season grasses and late partial harvest of warm-season grasses. Warm-season grasses in these communities were greatly reduced by repeated late harvest, slightly reduced by late harvest in alternate years, and slightly promoted by early harvest of cool-season grasses. The dominant cool-season grasses responded less to repeated early harvests than did the less abundant warm-season grasses to repeated late harvests. The hypothesis that different harvest schedules may lead to alternative equilibria is supported, and rest alone may not cause a shift from a cool-season dominated equilibrium toward a greater warm-season presence in the plant community.
    • 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.
    • 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.
    • 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.
    • 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.
    • California oak-woodland overstory species affect herbage understory: Management implications

      Ratliff, R. D.; Duncan, D. A.; Westfall, S. E. (Society for Range Management, 1991-07-01)
      Concerns for the future of California's oak-woodlands have intensified the need to better understand how different overstory species affect herbage standing crops and species frequencies. Data from over 8,000 plots harvested between 1961 and 1968 at the San Joaquin Experimental Range in the Sierra Nevada foothills of central California show that peak standing crops averaged 2,795 kg/ha in the open; 3,086 kg/ha under blue oak (Quercus douglasii); 1,840 kg/ha under interior live oak (Quercus wislizenii); 1,696 kg/ha under digger pine (Pinus sabiniana), and 1,917 kg/ha under buck brush (Ceanothus cuneatus). Overstory species affected standing crops differently on different range sites. On swales, standing crops were less under live oak and digger pine than in open areas. On open-rolling uplands, standing crops were less in the open and under live oak than under blue oak. On rocky-brush uplands, standing crops were less under all other overstory species than under blue oak. Data on species frequency suggest that herbage species of inter successional stages are more common under trees. The frequency of plant species varied with the species of overstory, and a diversity of overstory species may help to maintain adequate species diversity among understory species.
    • Cattle-deer interactions in the Sierra Nevada: A bioeconomic approach

      Loomis, J. B.; Loft, E. R.; Updike, D. R.; Kie, J. G. (Society for Range Management, 1991-07-01)
      Four potential cattle grazing systems on summer range in the Sierra Nevada are compared in terms of deer harvest, number of hunters attracted, and the net economic value of hunting. Research on deer carrying capacity response to different 3-year rest rotation grazing patterns indicates continuous moderate grazing provides 82% of the potential deer carrying capacity. A 2-years-off, 1-year-on grazing system provides 94% of potential deer carrying capacity. The increase in carrying capacity associated with grazing 1 year in 3 could increase buck harvest by 200 animals in the Sierra Nevada's hunt zone D5. Change in deer harvest in the previous year is one of the key variables in a model that determines the attractiveness of hunt zones to California deer hunters. The model predicts that increasing buck harvest by 200 deer in hunt zone D5 results in 2,721 more hunters visiting this zone each year. This translates into nearly 11,835 more trips. The net economic value of these additional hunters is determined based on a simulated market approach. Using the value from the hunter survey, the annual increase in hunting value is 2.3 million. The present value of this change over each 3-year rest-rotation cycle is 6.5 million using a 4% discount rate. The incremental benefits of deer hunting gained under the 2-years-off, 1-year-on grazing system is greater than the lost net economic value of the forage to the rancher as computed by USDA Economic Research Service.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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).