• An Evaluation of Beta Attenuation for Estimating Aboveground Biomass in a Tallgrass Prairie

      Knapp, A. K.; Abrams, M. D.; Hulbert, L. C. (Society for Range Management, 1985-11-01)
      The attenuation of beta particles by vegetation was evaluated as a nondestructive method for estimating aboveground biomass in tallgrass prairie in northeast Kansas. Regression equations using the sum of beta attenuation measurements for each of 5 height classes within the vegetation and mean midday leaf water potential as the independent variables were used to predict live and total biomass. Live and total biomass were better predicted on burned (r2=.91 and .88, respectively) than unburned sites (r2=.71$ and .70, respectively). Greater variability in the relationship between beta attenuation and biomass in unburned prairie was a result of the large and variable amount of dead biomass on unburned sites. Dead biomass was poorly predicted by beta attenuation (r2=.24-.49). Beta attenuation predicted biomass in burned tallgrass prairie within +/- 5% of harvest values until late season vegetative senescence. In unburned prairie, predictions were poorer, but the technique could still be useful if the required accuracy need be only +/- 25%.
    • Cattle Grazing Blue Grama Rangeland. I. Seasonal Diets and Rumen Fermentation

      McCollum, F. T.; Galyean, M. L.; Krysl, L. J.; Wallace, J. D. (Society for Range Management, 1985-11-01)
      Four field trials were conducted from early August to late October, 1982, on blue grama (Bouteloua gracilis) rangeland in south-central New Mexico to examine relationships among grazing season, diet botanical and chemical composition, and rumen fermentation in beef steers (Bos taurus). Diets contained an average of 83% grasses and 17% forbs from early August through late September and 77% forbs in late October. Cell wall content of the diet decreased from the early growing season (74.9%) through the onset of dormancy (64.9%) while acid detergent fiber and lignin increased (41.9 to 52.9% and 5.2 to 12.7%, respectively) and crude protein content declined from 18.4 to 11.7%. Soluble and insoluble nitrogen (N) fractions of the diet reflected crude protein; from 13 to 36% of N was in unavailable forms. The extent of in vitro organic matter digestion declined from the early growing season (66.5%) through onset of dormancy (47.9%). Ruminal ammonia concentrations declined as season progressed: 6.0 mg/100ml was the lowest concentration observed. Declining diet quality was accompanied by an upward shift in digesta pH and altered proportions of volatile fatty acids (VFA) in rumen contents. Total VFA concentration was highest in late August (106.3 mmoles/liter). Ruminal measures generally reflected changes in dietary protein and digestibility but concentrations could also reflect changes in digesta flow rates. Finally, data suggest that crude protein may not be a good measure of protein supply to livestock grazing on ranges with diverse forage types.
    • Cattle Grazing Blue Grama Rangeland. II. Seasonal Forage Intake and Digesta Kinetics

      McCollum, F. T.; Galyean, M. L. (Society for Range Management, 1985-11-01)
      Four field trials were conducted from early August to late October, 1982, on blue grama (Bouteloua gracilis) rangeland in south-central New Mexico, to examine relationships among grazing season, forage intake and digestive function in beef steers (Bos taurus). Organic matter intake declined from 24.0 g/kg body weight (BW) in early August to 17.4 g/kg BW in late September and then increased to 20.9 g/kg BW in the early dormant season (late October). From early growing season to early dormancy, diet digestibility and passage rates decreased while retention time of digesta in the rumen increased. Rate and extent of in vitro organic matter disappearance were 66.5, 6.7; 63.1, 6.7; 51.6, 4.8; and 47.9%, 5.6%/hour in early August, late August, late September and late October, respectively. Fluid and particulate passage rates (%/hour) were 24.9, 4.6; 12.7, 3.9; 11.1, 3.7; and 10.5, 3.5, respectively, for the same periods. Retention of particulate digesta varied from 26.1 hours in the early growing season to 34.3 hours in early dormancy. Gastrointestinal fill gradually increased as season progressed. Results suggest that maintenance of a diverse plant community, containing not only desirable grasses but also palatable forbs, may allow cattle to maintain a higher level of nutrient intake during periods of grass dormancy.
    • Denitrification and Bacterial Numbers in Riparian Soils of a Wyoming Mountain Watershed

      Hussey, M. R.; Skinner, Q. D.; Adams, J. C.; Harvey, A. J. (Society for Range Management, 1985-11-01)
      The presence and activity of denitrifying bacteria as well as bacteria capable of reducing sulfate in 1 upland and 5 riparian soils of a mountain watershed in Wyoming were studied. Bacteria were enumerated from soil samples collected during summer along transects placed perpendicular to stream flow. Samples were taken at 3 depths within each plant community. Subsamples were frozen and later utilized to determine denitrification potential. Higher counts of total heterotrophic aerobic bacteria, sulfate-reducing bacteria, denitrifying bacteria, and denitrification potential existed in the upper 5 to 15 cm of soil than at 30 cm. Soils located close to the stream's edge tended to have more bacterial activity than those further from the stream, indicating that these soils may be important areas for nitrate and sulfate reduction. Soil organic matter and water content decreased with depth in all plant communities, and those closer to the stream contained more organic matter and water than those further from the stream.
    • Dietary Overlap Among Axis, Fallow, and Blacktailed Deer and Cattle

      Elliott, H. W.; Barrett, R. H. (Society for Range Management, 1985-11-01)
      Seasonal diets of native Columbian black-tailed deer (Odocoileus hemionus columbianus) and exotic axis deer (Axis axis axis), fallow deer (Dama dama dama), and cattle (Bos taurus) on Point Reyes National Seashore were determined by microhistological technique to assess their dietary overlap. Throughout the year black-tailed deer ate mostly forbs, axis deer and fallow deer ate mostly grasses and forbs, and cattle ate mostly grasses. Only a few plant species comprised most of their diets. Percent composition of food species was not related to their preference indexes. Diets of axis and fallow deer overlapped more with each other and cattle than with black-tailed deer except during the summer when the dietary overlap among all species was similar at a lower level. Comparison of seasonal diets of deer with this and other studies indicated that food consumption of deer was not limited to particular food classes.
    • Dormancy Breaking and Germination Requirements of Nimble Will (Muhlenbergia Schreberi Gmel.) Seeds

      Baskin, J. M.; Baskin, C. C. (Society for Range Management, 1985-11-01)
      Nimble will (Muhlenbergia schreberi Gmel.), a native perennial C4 grass, is a serious weed in horse pastures in the Bluegrass Region of Kentucky. This study investigated the dormancy breaking and germination requirements of this species. Seeds mature in October, are dispersed mostly during autumn and winter, and germinate in spring. Seeds were dormant at maturity, but they became nondormant during (1) dry storage in the laboratory, (2) 99 days of incubation on moist sand at 35/20 degrees C, or (3) cold stratification. Germination percentages were higher in light than in darkness, and cold stratified seeds germinated to higher percentages than dry-stored seeds. Seeds sown in a nonheated greenhouse in autumn were cold stratified during winter, and they germinated in spring when temperatures became nonlimiting. However, seeds that remained on the parent plants in the field over winter did not gain the ability to germinate at spring temperatures (20/10 degrees C) by spring. Under some test conditions, the intact palea and lemma inhibited germination, but under other conditions they were not inhibitory.
    • Effects of Clipping on Burned and Unburned Creeping Bluestem

      Kalmbacher, R. S.; Martin, F. G.; Terry, W. S.; Hunter, D. H.; White, L. D. (Society for Range Management, 1985-11-01)
      Creeping bluestem (Schizachyrium stoloniferum), a major decreaser on Florida range, is adversely affected by grazing during the growing season after a winter burn. To compare the effect of defoliation of burned and unburned bluestem range, creeping bluestem was burned (or not burned) on 2 similar sites in February 1978 and 1979 and cut at 2, 4, 6, 8, and 10 months after burning. Once forage was initially cut, it was recut every 2 months. Dry matter (DM) yield, tiller density, total nonstructural carbohydrate (TNC), crude protein (CP), and in vitro organic matter digestibility (IVOMD) were determined. When forage was cut in April and recut every 2 months, average yield of creeping bluestem from unburned areas was 3,000 kg/ha while that of burned was 2,350 kg/ha. Creeping bluestem yield from unburned areas declined linearly within both years as initial harvest was delayed, but delaying initial harvest date had no effect on forage yield from burned areas. Final tiller density was usually a cubic response in burned and unburned plants. Tiller density generally increased in plants cut 1 month after treatment, decreased in plants cut 2, 4, 6 months after treatment, and increased in plants cut 10 and 12 months after treatment. Rhizomes of plants burned in February 1979, cut initially in April, and reharvested 4 times had 9.0% TNC in March 1980, while unburned plants contained 10.2% TNC. The response of CP and IVOMD in initial growth was quadratic or cubic with time of initial harvest because percentages were raised initially due to burning, then they dropped steadily to a low in August, after which they began to rise slightly. Protein content in unburned forage had either a negative linear response or had no significant regression with time of initial harvest. IVOMD in unburned forage exhibited a quadratic (1978) or a polynomial (1979) response with time of initial harvest where IVOMD increased or fluctuated in the growing season, usually decreasing in fall and winter. Analysis of regrowth data indicated that the response of crude protein and IVOMD was similar regardless of burn treatment. Quality of regrowth declined from June to August and steadily increased from August to December. Creeping bluestem would be weakened by grazing on 60-day intervals after a February burn. When prescribed burning of creeping bluestem range is carried out every 3 to 4 years, deferment of grazing until June after a February burn will allow grazing of relatively high quality forage and still maintain creeping bluestem stand vigor.
    • Effects of Jackrabbit Grazing, Clipping, and Drought on Crested Wheatgrass Seedlings

      Roundy, B. A.; Cluff, G. J.; McAdoo, J. K.; Evans, R. A. (Society for Range Management, 1985-11-01)
      The effects of black-tailed jackrabbits on crested wheatgrass (Agropyron desertorum) seedling establishment and utilization were monitored on a mesic and 2 xeric Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis) sites in Nevada. Although jackrabbit densities (1.4 to 2.9/ha) and utilization were high, seedling survival was not significantly different (p≤0.05) inside or outside rabbitproof exclosures even on the xeric sites during drier-than-normal springs. Seedling density was greater on the mesic than xeric sites, but good grass stands were produced on all sites. The smaller seeded areas (less than 60 ha) and the edge of the large seeded area (400 ha) had the greatest forage utilization by rabbits. To determine the effects of defoliation and drought on seedling survival, seedlings in small tubes (3.8 cm diameter and 20 cm deep) and in large tubes (10 cm diameter and 1 m deep) were watered and clipped at 7 different intervals. Seedlings grown in the smaller volume were more sensitive to clipping and drought than those grown in the larger soil volume. Seedlings watered less than weekly showed a trend toward higher survival when clipped every 3 or 4 weeks than when clipped more or less frequently. Clipping weekly and watering less than weekly greatly reduced root growth and seedling survival. Although infrequent grazing by rabbits could slightly increase seedling survival in a dry year, the additive effects of frequent grazing and drought could result in stand failure, especially on shallow or rocky soils with a small soil volume that limits water retention and root growth.
    • Effects of Tillage and Manure on Emergence and Establishment of Russian Wildrye in a Saltgrass Meadow

      Meuller, D. M.; Bowman, R. A.; McGinnies, W. J. (Society for Range Management, 1985-11-01)
      Saltgrass [Distichlis stricta (Torr.) Rydb.] meadows are found in lowland areas throughout the western United States. Saltgrass meadows are frequently more moist than upland sites and have good production potential if relatively unpalatable saltgrass is replaced by a more palatable species. The electrical conductivity and sodium absorption ratio of saltgrass meadow soils often increase with soil profile depth, while total N and sodium-bicarbonate extractable P decrease. Cultural practices that do not mix the deeper, more saline horizons with the surface should increase seedling germination and establishment. Field studies evaluated the effects of chisel plowing followed by vertical-axis tilling, conventional tilling (moldboard-plowing and discing), and manure (0, 11, 22, 45, and 90 Mg/ha) on soil physical and chemical characteristics as they relate to germination and establishment of Russian wildrye [Elymus junceus Fisch.]. Chisel plowing followed by vertical-axis tilling increased seedling emergence by 23% over conventional tillage. Manure increased seedling growth and emergence, but had no effect on stand ratings. The poor physical conditions created on the conventionally tilled plots when the B and C horizons were brought to the surface and organic matter was buried by the plow are believed to have caused the difference in seedling counts between the two tillage treatments.
    • Evaluation of Wolf Control to Reduce Cattle Predation in Alberta

      Bjorge, R. R.; Gunson, J. R. (Society for Range Management, 1985-11-01)
      Results of wolf (Canis lupus) control to reduce predation of cattle in northwestern Alberta are reported. Numbers of wolves declined from about 40 prior to control to 3 following the strychnine poisoning of 26 wolves during 2 winters, 1979-80 and 1980-81. Additional losses of wolf pack members occurred from natural mortality and dispersal following the removal of the majority of their packmates. In 3 of 6 instances where packs took baits, entire packs of 2, 4, and 6 wolves were killed. Ingress of wolves occurred within 1-2 years. Total mortality of cattle declined from a mean of 64 (3.4%) during 4 years prior to control to 36 (2.0%) during 2 years following control. Selectivity of strychnine poisoning was reasonably good although more emphasis on preventive management is recommended.
    • Morphology and Growth in Seedlings of Several C4, Perennial Grasses

      Coyne, P. I.; Bradford, J. A. (Society for Range Management, 1985-11-01)
      Establishment of forage grasses depends upon their ability to compete for resources in the critical seedling establishment phase. Desirable native grass species are generally considered to be more difficult to establish from seed than the introduced Old World bluestems (Bothriochloa spp.), although comparative data are generally lacking. This study compared the responses of morphological attributes commonly associated with seedling vigor and some growth parameters in 17 perennial, C4 grasses including 5 native and 12 Old World bluestems. Plants were grown in a greenhouse under well-watered and limited watering regimes. The objective was to document differences in morphology and growth among these grasses from emergence through 7 weeks post emergence. The Bothriochloa species generally rated higher than the native species in morphological characters commonly associated with seedling vigor. The exotics produced as much or more biomass and had more leaf area per plant, more tillers, and leaves per tiller than the natives. Although the native grasses produced less leaf area, the cost of these leaves in terms of biomass per unit area was higher than in the introduced grasses. The natives tended to partition relatively more biomass aboveground and more of this to leaves, rather than sheaths plus stems, than the Old World bluestems. However, partitioning of total plant biomass among roots, sheaths plus stems, and leaf blades was remarkably insensitive to water stress in all entries. Approximately one-third of total biomass was partitioned among leaf blades, sheaths plus stems, and roots, respectively, with sheaths+stems tending to be a slightly smaller fraction than the other 2 components. Recurring water stress cycles reduced most parameters significantly and generally accentuated the normal ontogenetic decline in relative growth and unit rates. Across all entries, total plant biomass and leaf blade area were reduced over 40% by a limited watering regime. Although water stress reduced the size of the assimilatory surface, the remaining leaves were more efficient in the production of new biomass. This response correlated with an increase in specific leaf weight under water stress.
    • Plant Associations within the Interior Valleys of the Umpqua River Basin, Oregon

      Smith, W. P. (Society for Range Management, 1985-11-01)
      Eleven plant associations were identified and characterized according to the frequency, percent cover, and relative dominance of the herbaceous and woody species among the vegetative strata, including stem density, diameter breast height (dbh), and basal area for tree species: Cynosurus echinatus/Taeniatherum asperum; Bromus mollis/Cynosurus echinatus; Rhus diversiloba/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Taeniatherum asperum/Cynosurus echinatus; Quercus garryana/Rhus diversiloba/Dactylis glomerata; Pseudotsuga menziesii/Quercus garryana/Rhus diversiloba/Polystichum munitum; Quercus garryana/Arbutus menziesii/Rhus diversiloba/Cynosurus echinatus; Arbutus menziesii/Rhus diversiloba/Festuca arundinacea; Quercus garryana/Fraxinus latifolia/Rosa elganteria/Juncus effusus; Pseudotsuga menziesii/Corylus cornuta/Cynosurus echinatus. The intensity and duration of recent disturbance distinguished early seral stages which were characterized by a paucity of native shrub and herbaceous species and an abundance of annual invaders in the understory. The primary forces that influenced existing plant assemblages were fire and more recently agricultural practices, especially among grasslands and savannas. Grasslands without recent livestock use exhibited greater species diversity, supporting more species and a more homogeneous distribution of relative abundance among species.
    • Precipitation, Soils and Herbage Production on Southeast Wyoming Range Sites

      Hart, R. H.; Samuel, M. J. (Society for Range Management, 1985-11-01)
      Herbage production and precipitation were determined at 13 locations in 483 ha of mixed grass range 1975-1979; production was determined at all locations 1982-1983, but precipitation was measured only at the main weather station. Vegetation and herbage production were more uniform on sites with similar subsoil than on sites with similar surface soil, the usual basis for site classification. Within any year, herbage production on similar sites was not correlated with spatial distribution of precipitation. Across years 1975-1979 and 1982-1983, herbage production on sites with sandy subsoil was correlated with March-April weather station precipitation (r2=0.866**) and March-April plus May-August precipitation (R2=0.95**). Herbage production on sites with loamy subsoil was not significantly correlated with precipitation in March-April (r2=0.32) or any other period.
    • Recovery of Vegetative Cover and Soil Organic Matter During Revegetation of Abandoned Farmland in a Semiarid Climate

      Dormaar, J. F.; Smoliak, S. (Society for Range Management, 1985-11-01)
      Much of the farmland in the Canadian Prairie region has been abandoned over the years and allowed to revert to weedy cover and eventually to grassland. While some of the changes in vegetation during plant succession have been documented, limited information is available on changes in soil characteristics. The purpose of this study was to assess the vegetative cover and soil transformation under similar semiarid climatic conditions with an annual precipitation of about 310 mm on 3 sites abandoned in 1925, 1927, and 1950 as compared to adjacent native range. Total C and N, water-stable aggregates between 1.0 and 5.0 mm, and polysaccharide content increased, while chelating resin-extractable C, humic acid/fulvic acid ratios, caloric content of the rootmass, and dehydrogenase activity decreased in the successional sequence. Nevertheless, more than 55 years will be required to allow soil to return to native range standards under moderate grazing by livestock. Revegetated range may have to be subjected to lighter grazing pressures than usual to allow the vegetation to continue to increase its rootmass and thus the soil chemical properties. A hypothesis to explain changes in root- and top-mass ratios with time on the basis of the quality of soil nitrogen has been advanced.
    • Storage Life of Illinois Bundleflower and Western Indigo Seed

      Call, C. A. (Society for Range Management, 1985-11-01)
      Seed of Illinois bundleflower (Desmanthus illinoensis (Michs.) MacM.) and western indigo (Indigofera miniata var. leptosepala (relative humidity were imbibed in a controlled environment for 20 Turdays with a night/day temperature regime of 15/25 degrees C and a 12-hour en stored for 1 to 4 years at 16 degrees C and 40% photoperiod. Preimbibition treatments included acid scar-ification by immersion in concentrated sulfuric acid for 15 minutes, mechanical scarification by cutting the seed coat at the end opposite the micropyle, and an untreated control. Seed viability was determined by a triphenyl tetrazolium chloride test. Germination rate and cumulative germination decreased for untreated Illinois bundleflower seed and increased for untreated western indigo seed as the length of storage increased from 1 to 4 years. The decrease in germinability of Illinois bundleflower seed was related to the development of an impermeable seed coat, while the increase in germinability of western indigo seed was related to a decease in hard seededness and the fulfillment of after-ripening requirements. Scarification treatments increased cumulative germination and germination rates in each seed storage class for both species. Over the 4-year storage period, Illinois bundleflower seed viability decreased by approximately 10%, and western indigo viability remained relatively constant.
    • Technical Notes: The relationship of stocking intensity and stocking pressure to other stocking variables

      Scarnecchia, D. L. (Society for Range Management, 1985-11-01)
      Stocking intensity and stocking pressure have been defined and used as technical stocking variables describing animals on pasture. Relationships between these variables and stocking variables such as stocking density and stocking rate are discussed. One conclusion is that stocking intensity and stocking pressure are not informationally unique variables, but are equivalent to stocking variables defined in other work. Retention of the terms stocking intensity and stocking pressure is recommended for nontechnical use in describing livestock grazing.
    • The Effects of Fire on the Blackbrush (Coleogyne ramosissima) Community of Southwestern Utah

      Callison, J.; Brotherson, J. D.; Bowns, J. E. (Society for Range Management, 1985-11-01)
      Eight general study sites were examined in the blackbrush (Coleogyne ramosissima) zone of southwestern Utah in order to assess the impact of burning. All sites had been burned. Age since burning varied from 1 to 37 years. Plots were placed in burned areas with plots in adjacent unburned areas serving as controls. Sites were similar enough that definite trends were distinguishable despite between site variation. Recently burned areas were dominated by forbs, middle aged burns were dominated by grasses, and the oldest burns had reverted back to shrub dominance. Cryptogamic soils crusts were severely affected by burning and showed no signs of recovery after 19.5 years. Blackbrush was also severely affected and showed no signs of recovery after 37 years. Lack of recovery by blackbrush may be due to its paleoendemic nature. Future burning of stands of blackbrush in southwestern Utah is not recommended.
    • The Role of Fourwing Saltbush in Mined Land Reclamation: A Viewpoint

      Booth, D. T. (Society for Range Management, 1985-11-01)
      Ease of establishment by direct seeding has resulted in fourwing saltbush [Atriplex canescens (Pursh) Nutt.] becoming the principal, sometimes the only, shrub on certain revegetated mined lands in Wyoming. To prevent dense stands that might exclude other shrub species, the Wyoming Department of Environmental Quality-Land Quality Division, now limits the amount of fourwing saltbush that can be included in a reclamation seed mix. There is evidence that fourwing saltbush may aid, rather than hinder, the establishment of other shrubs. A thesis is developed for fourwing's role as a pioneer species that creates ecosystem diversity, auguments the invasion of late-succession plants, and declines in density as succession progresses. The shrub is recommended as a means to direct succession toward successful reclamation. Mine managers are cautioned that the rate of natural invasion of climax species into seeded stands of fourwing saltbush is not known.
    • Variation and Names in the Poa secunda Complex

      Kellogg, E. A. (Society for Range Management, 1985-11-01)
      The members of the Poa secunda complex were studied using transplant experiments, morphological studies of population samples, and various numerical taxonomic techniques including principal components analysis and discriminant analysis. The complex is shown to comprise 2 species: Poa curtifolia, a serpentine endemic from central Washington, and P. secunda, a widespread polymorphic rangegrass. Other forms may be recognizable locally, but do not represent separate evolutionary lines. If range managers need names for these local forms, the names should be informal English names rather than Latin binomials.