• 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.