• Environmental Factors Influencing Gardner Saltbush Seed Dormancy Alleviation

      Ansley, R. J.; Abernethy, R. H. (Society for Range Management, 1985-07-01)
      Pregermination treatments applied to seed of Gardner saltbush, [Atriplex gardneri (Moq.) D. Dietr.] were evaluated for alleviation of seed dormancy. Treatments selected simulated conditions the seed might be exposed to in its natural environment, including dry afterripening, scarification, leaching, and cold stratification. Germination response to individual treatments was equal to or higher than nontreated seed. Germination percentage of afterripened seed was increased from 17% for nontreated filled seed to an average of 86% of filled seed by the combined treatments of scarification, leaching, and 4-week stratification. This combination of treatments allowed optimum germination. Response to treatments provided evidence as to the type of dormancy in Gardner saltbush seeds. The levels of germination response to specific treatments appears to be an adaptation to ensure a temporal dispersal of dormancy release and seedling emergence. Pregermination treatments used in this study were relatively easy to apply to the seeds and stimulated germination without potentially damaging the embryo. Thus, they would be useful in revegetation by direct seeding efforts.
    • Forage Use by Cattle and Sheep Grazing Separately and Together on Summer Range in Southwestern Utah

      Ruyle, G. B.; Bowns, J. E. (Society for Range Management, 1985-07-01)
      Grazing trials were conducted on high elevation summer range in southwestern Utah, with cattle and sheep stocked separately and together in .4-ha paddocks. Vegetation measurements were taken before and after grazing treatments to quantify vegetation utilization as measured by several sampling techniques. Sheep removed less grass and more forbs and shrubs than cattle. Cattle showed a strong reluctance to browse mountain snowberry (Symphoricarpos oreophilus Gray) even when herbaceous forage was greatly reduced. In the common use grazing treatments, all 3 forage categories were well utilized. Cattle and sheep grazing together used more forage, especially mountain snowberry, than calculated from single use averages.
    • Effects of Hunger Satiation on Diet Quality by Grazing Sheep

      Jung, H. G.; Koong, L. J. (Society for Range Management, 1985-07-01)
      The effect of hunger satiation on selectivity for diet quality by sheep grazing a smooth bromegrass (Bromus inermis) pasture was studied with esophageal fistulated sheep. Fifteen wethers (45.8 +/- .7 kg) were allotted to 5 treatments: nonfasted, fasted for 16 h and then fed 0, 135, 271, or 407 g of pelleted feed. Nonfasted animals were confined at 0800 h and sheep receiving pellets were fed at 0700 h. One animal from each treatment was included in groups released for grazing at 0900, 0930, and 1000 h. Sheep grazed the smooth bromegrass pasture for 30 min. The experiment was conducted on 4 consecutive days. Nonfasted sheep had a lower rate of intake than fasted animals (0 g pelleted feed) (47 vs. 124 mg/min/kg BW^0.75, P<.05), but the quality of the diet selected did not differ (P>.05). All treatment groups selected diets of higher quality than the green fraction of the pasture collected by handclipping. Consumption of increasing quantities of pelleted feed by fasted animals resulted in linear (P<.05) increases in in vitro dry matter disappearance and crude protein content of diet samples. Rate of forage intake and cell wall content of the ingested forage declined linearly (P<.05) with increasing consumption of pelleted feed by previously fasted sheep. Composition of forage cell wall material in the diet samples also changed with pellet feeding, cellulose content increased while lignin content decreased. Overnight fasting of esophageal fistulated sheep did not influence selectivity for forage quality relative to nonfasted animals, but satiation of hunger, as a result of ingestion of a highly digestible feed after a fast, resulted in increased diet quality selected by the animals.
    • Ranch Resource Differences Affecting Profitability of Crested Wheatgrass as a Spring Forage Source

      Spielman, K. A.; Shane, R. L. (Society for Range Management, 1985-07-01)
      A representative cow-calf ranch operation in Elko County, Nev., was modeled using a linear programming procedure to determine effects of selected ranch resource differences on profitability of seeding crested wheatgrass. Net present value (NPV) results suggest seeding crested wheatgrass as a spring forage can be a profitable investment if there are associated increases in calf weaning weights of 9.07 kg and increases in calving rates of 5 percentage points. Amount of meadow hayland, deeded range, and BLM forage available to the representative ranch were increased and decreased 50%. NPV's of the crested wheatgrass investment are greater for ranches with excess meadow hay and excess deeded range. NPV's are lower for ranches with limiting resources of meadow hayland, deeded range, and BLM forage.
    • Response of Vegetation of the Northern Great Plains to Precipitation Amount and Grazing Intensity

      Olson, K. C.; White, R. S.; Sindelar, B. W. (Society for Range Management, 1985-07-01)
      Changes in basal cover of vegetation were predicted in response to variation in precipitation and grazing intensity. Multiple regression analysis was used with basal cover as a dependent variable and precipitation parameters as independent variables to develop predictive equations. Predicted cover values were used to develop three dimensional response surfaces which describe individual species responses to fluctuating precipitation and different grazing intensities. Results indicate that each species reacts to precipitation regimes and grazing pressure in a unique manner. Continual changes in basal cover can be expected in the plant community as the precipitation regime changes. Moderate grazing intensity, approximately 0.92 ha (2.3 acres) per AUM, appears to be most conducive for maintaining vegetative cover that is desirable for livestock production. However, stocking rate changes need to be anticipated and planned to coincide with available forage because of large fluctuations in cover due to varying precipitation.
    • Magnification and Shrub Stemmy Material Influences on Fecal Analysis Accuracy

      Holechek, J. L.; Valdez, R. (Society for Range Management, 1985-07-01)
      When 100X and 200X microscope magnification levels were used singly and interchangeably in microhistological analysis, magnification level had no effect (P<.05) on diet botanical composition of 60% grass and 60% forb diets containing 6 forage species fed to mule deer. However, large differences occurred between magnification levels for individual plant species in a 60% shrub diet containing the same forage species. The use of the 100X and 200X magnification levels interchangeably was slightly more accurate than exclusive use of either magnification level for the high grass and high shrub diets. For fecal analysis our study shows 100X and 200X microscope magnification levels can be used singly or interchangeably with little influence on accuracy. Use of the 100X magnification level to scan fields for potentially identifiable fragments followed by switching to 200X magnification for better resolution of fragments difficult to discern can slightly improve both speed and accuracy. Fourwing saltbush, which had a high proportion of stemmy material relative to leaves, was severely underestimated in the feces of all 3 diets. Our data indicate fecal analysis has limited value as an estimator of diets of herbivores, such as mule deer, that consume significant but variable quantities of stemmy material from shrubs.
    • Some Responses of Riparian Soils to Grazing Management in Northeastern Oregon

      Bohn, C. C.; Buckhouse, J. C. (Society for Range Management, 1985-07-01)
      Infiltration, sediment production, penetrometer penetrability and bulk density were measured on control/treatment paired plots of several grazing schemes in a riparian zone of northeastern Oregon. Treatments were in effect over a period of 5 years. Rest-rotation favored the hydrologic parameters measured, while deferred rotation and season-long did little to enhance, and sometimes hindered, hydrologic expression. Late-season grazing in September demonstrated a positive hydrologic response, whereas late-season grazing in October was negative-probably due to the onset of fall rains and a change in soil moisture conditions.
    • The Animal-Unit and Animal-Unit-Equivalent Concepts in Range Science

      Scarnecchia, D. L. (Society for Range Management, 1985-07-01)
      The terms animal-unit and animal-unit-equivalent have evolved as a means of expressing different kinds and classes of livestock in a common form. This paper discusses the evolution of the concepts, analyzes their conceptual boundaries, and discusses their use in the analysis of range livestock systems. Recent efforts to modify these concepts to develop livestock species substitution ratios for specific ranges are discussed. For greater usefulness in describing range livestock systems, animal-unit-equivalents should be calculated based only on animal-related factors. Also, the animal-unit-equivalent concept should not be redefined in the calculation of pasture-specific substitution ratios.
    • Temperature and Water Stress Effects on Growth of Tropical Grasses

      Bade, D. H.; Conrad, B. E.; Holt, E. C. (Society for Range Management, 1985-07-01)
      Coastal bermudagrass (Cynodon dactylon (L.) Pers.) and Kleingrass "75" (Panicum coloratum L.) were grown under controlled environments to evaluate the effects of high growth temperatures and water stress on forage growth. Plants were grown under a controlled environment with 14/10 hour day/night temperatures of 30/20, 35/25, and 40/30 degrees C; 2 water regimes; and 3 stages or ages of regrowth at harvest. High growth temperatures significantly (P<0.05) increased dry matter yield and accelerated tiller number and the maturation rate of the plants. Significant (P<0.05) increases in leaf area, weight per tiller, and plant height were observed as growth temperatures were increased. Reduction of number of tillers per pot due to water stress reduced dry matter yields approximately 38%. The percent leaf was greater for the water-stressed plants than for the well-watered plants, but the leaf area per plant was less due to reduction of growth and delayed maturation. Dry matter yield of water-stressed plants grown under higher temperatures increased more than corresponding well-watered plants as a result of increased rate of stem elongation and leaf development. Though water-stressed plants were shorter and had less leaf area than well-watered plants, the relative increase in both height and leaf area at higher temperatures of stressed plants was greater than well-watered plants. Apparently supraoptimal temperature (40 degrees C) does not have a negative effect on yield in the presence or absence of moisture stress.
    • Soil and Vegetation Relationships in a Central Plains Saltgrass Meadow

      Bowman, R. A.; Mueller, D. M.; McGinnies, W. J. (Society for Range Management, 1985-07-01)
      A field study was conducted in a saltgrass (Distichlis stricta) meadow at the Central Plains Experimental Range to investigate relationships between soil types, salinity, sodicity, fertility, and vegetation ground cover and species composition. Three line transects that included 48 soil cores and their adjacent vegetation cover were sampled. Soils data indicated relatively good homogeneity between transect 1 and 3 with transect 2 exhibiting the poorest soil physical characteristics because of shallow A horizon and high sodium. Species composition averaged across transects reflected in general the following magnitude of ground cover distribution over the 1979-1983 seasons: blue grama (Bouteloua gracilis) > alkali sacaton (Sporobolus airoides) > saltgrass > western wheatgrass (Agropyron smithii). Species nutrient concentration data showed western wheatgrass with the highest concentration of N and K, alkali sacaton highest in P, Ca, Mg, and Na. Saltgrass was assimilating primary NaCl and alkali sacaton NA2SO4. Blue grama showed low Na and Cl concentrations, which suggested a superficial rooting pattern above the saline horizons. Plant-soil correlations for all transects are discussed.
    • Influence of Canopy Characteristics of One-seed Juniper on Understory Grasses

      Schott, M. R.; Pieper, R. D. (Society for Range Management, 1985-07-01)
      Studies were conducted in the Sacramento Mountains, New Mexico, to determine the influence of juniper (Juniperus monosperma [Engelm.] Sarg.) canopy on understory vegetation. The basal area of grass species was estimated at 6 locations beneath the canopies of 50 one-seed junipers. Other parameters measured were litter depth, canopy height, canopy cover, canopy closure, tree height, trunk diameter, north-south crown diameter, and east-west crown diameter. Locations adjacent to the trunk had the greatest juniper canopy cover and litter depths, and the lowest height to canopy. Locations at the end of the canopy had the least crown cover and litter depths, and the greatest height to canopy. All but one of the grass species had greater basal areas at the edge locations and the least at the interior locations beneath juniper canopies. Pinyon ricegrass (Piptochaetium fimbriatum [H.B.K.] Hitch.) was the exception; it was never found at the exterior locations. Regression models indicated that shading influenced the basal areas of most grass species. Litter depth was negatively correlated with grass basal cover in only 4 models and positively correlated in 1. Basal area of pinyon ricegrass was positively correlated with trunk diameter, a reflection of tree age, indicating that the grass requires time to become established. Also, basal area of pinyon ricegrass was positively correlated with canopy cover, indicating that this species requires the modified microenvironment afforded by shading.
    • The Use of Supplement Blocks for Sheep Grazing Dry, Annual Pastures in California

      DePeters, E. J.; Dally, M. R.; Alwash, A. A.; Therkelsen-Tucker, P. (Society for Range Management, 1985-07-01)
      The objective of this study was to evaluate the use of supplement blocks on body weight change, blood parameters, and lambing performance of ewes grazing dry, annual grasses during the summer prior to and during breeding. Two experiments were conducted in successive years to compare performance of unsupplemented control (C) and supplemented (S) Targhee ewes. In the first season, yearling ewes were used while aged ewes (2 or 4 years) were used during the second season. During the first year (1980), supplemented ewes lost less body weight during the dry grazing season than C ewes. However, no lambing performance difference was found between C and S groups. During the second year (1981), supplemented ewes maintained their body weight over the summer while C ewes lost weight. In addition, lambing performance (multiple births) was higher for S than C ewes. Supplementation of ewes with blocks containing molasses, urea, protein, and minerals required little labor input. However, based on lambing performance, it is unlikely that supplementation would be economically profitable under the range conditions utilized in these trials.
    • Effects of Secondary Metabolites from Balsam Poplar and Paper Birch on Cellulose Digestion

      Risenhoover, K. L.; Renecker, L. A.; Morgantini, L. E. (Society for Range Management, 1985-07-01)
      Inhibitory effects of metabolites from balsam poplar (Populus balsamifera) and Alaskan paper birch (Betula papyrifera) on cellulose digestion in vitro were examined. Significant inhibition of cellulose digestion occurred at concentrations of 5 mg per gram of substrate for benzyl alcohol, cineole, papyriferic acid, and a steam distillate fraction from juvenile paper birch. Digestibility declined as increasing amounts of resin were added to the substrate, but the rate of inhibition declined with each concentration increment. Secondary metabolites present in resins of paper birch and balsam poplar appear to be important in determining the relative nutritive quality of these species.
    • Economic Returns from Burning Tobosagrass in the Texas Rolling Plains

      Ethridge, D. E.; Sudderth, R. G.; Wright, H. A. (Society for Range Management, 1985-07-01)
      Based on 7 prescribed burning trials on tobosagrass (Hilaria mutica) in the Rolling Plains of Texas from 1968 to 1976, burned tobosagrass ranges yielded an additional present value of $36.16/ha ($14.64/ac) over 5 years with calf prices at $1.62/kg ($.731 lb). Additional costs are $10-12.50/ha ($4-5/ac). These results are based on average precipitation on ranges which had prior chemical treatment on mesquite. The prescribed burns were conducted according to recommended practices.
    • Emergence and Survival Response of Seven Grasses for Six Wet-Dry Sequences

      Frasier, G. W.; Cox, J. R.; Woolhiser, D. A. (Society for Range Management, 1985-07-01)
      A greenhouse study was conducted to determine seedling emergence and survival responses of 7 warm-season grasses to 6 combinations of initial wet-day and dry-day water sequences. Two factors which affected the number of seedlings that survived the first wet-dry watering sequence following planting were: (1) the number of seedlings produced in the first wet period which developed sufficient vigor to survive the subsequent drought or dry period, and (2) the number of ungerminated but viable seeds which remain after the first wet-dry watering sequence. Sideoats grama (Bouteloua curtipendula (Michx.) Torr.) seedlings emerged within 18 h of the initial wetting, with maximum numbers occurring on days 2 and 3. There was a high seedling mortality during the dry periods. 'Cochise' lovegrass (Eragrostis lehmanniana Nees × E. trichophora Coss and Dur.), 'Catalina' Boer lovegrass (E. curvula var. conferta (Schrad.) Nees), and 'A-130' and 'SDT' blue panicgrass (Panicum antidotale Retz) emerged on day 2 or later, and maximum seedling counts occurred on days 4 to 6. 'A-68' Lehmann lovegrass (E. lehmanniana Nees) and 'A-84' Boer lovegrass did not have significant emergence until there were 3 or more consecutive wet days. Seedling mortality, during dry periods of 2 to 7 days following initial wetting, ranged from 0 to 70% of the viable seeds. Survival characteristics of the grasses were not directly affected by total water loss. There were differences within varieties of the same species, and some grasses were better suited for surviving short term droughts during early seedling stages. These studies provided information showing how the survival characteristics of plants to the first wet-dry watering sequence can be used to assist in selecting species for range revegetation.
    • Effects of Moisture and Temperature on Germination of Idaho Fescue

      Doescher, P.; Miller, R.; Winward, A. (Society for Range Management, 1985-07-01)
      Germination response to varying temperatures and water stress levels during a 30-day incubation period was observed in 4 eastern Oregon collections of Festuca idahoensis Elmer. Seeds were selected from the following habitat types: Artemisia tridentata ssp. wyomingensis/Festuca idahoensis (ARTRV/FEID), Pinus ponderosa Dougl./Festuca idahoensis (PIPO/FEID). One stand of each habitat type was sampled, except for the ARTRV/FEID habitat type where seed was selected from both a high and low elevation plant community. The low elevation stand will be designated ARTRV"L"/FEID. Incubation temperature treatments were held constant (+/- 2 degrees C) and ranged in 5 degrees C increments from 5 degrees C to 35 degrees C. At 15, 20, and 25 degrees C, water stresses of 0.0 MPa, -0.6 MPa, and -0.9 MPa were depressed using polyethylene glycol 6000. Collectively, maximum total germination for all collections occurred at and above 10 degrees C and below 30 degrees C. Germination percentages for seeds from ARTRW/FEID, ARTRV/FEID and PIPO/FEID habitat types at 10 degrees C were 93.0, 97.0, 91.9, and 88.8%, respectively. Maximum germination rates for all collections occurred between 20-25 degrees C. As water stress decreased and temperature increased, both germination amount and rate for the 4 collections declined. Seeds of Idaho fescue collected from sagebrush habitat types maintained higher germination amounts and faster germination rates over wider temperature and moisture stress regime than did seeds selected from the PIPO/FEID site.
    • Evaluation and Management of Grasses for Dual Livestock and Game Bird Use

      Holt, E. C.; Cain, J. R.; Hendler, R. J. (Society for Range Management, 1985-07-01)
      Kleingrass 75 and Verde kleingrass (Panicum coloratum L.), PI 217229 and PMT 4022 plains bristlegrass (Setaria macrostachya H.B.K.) Nees), and commercial green sprangletop (Leptochloa dubia (H.B.K.), were studied for forage and seed production. Acceptability of seed was studied using caged bobwhite quail (Colinus virginianus). Defoliation management practices had relatively little influence on forage yield. Forage digestibility declined rapidly when defoliation was delayed, and the species responded differently in the rate and pattern of decline. Seed yields were as high or higher with 30-day interval harvesting as with deferred harvesting except that spring deferment increased kleingrass and summer deferment increased green sprangletop seed yields. Green sprangletop also produced more seed by leaving a 20-cm stubble than a 10-cm stubble. These indeterminate species apparently mature seed in approximately 30 days, indicating that a management system that leaves some tillers intact for 30 days or longer will result in some seed formation. Seed production decreases to nil in 2 to 3 months following first maturity in an undefoliated stand. Bobwhite quail readily consumed kleingrass seed as a significant portion of their diet even in the presence of a high quality game bird diet. They subsisted for short periods on an all grass seed diet, but consumed little plains bristlegrass or green sprangletop when game bird diet, pearl millet, or kleingrass were present. Thus, kleingrass has the most potential of the species studied for dual use.
    • Factors Affecting Forage Intake by Range Ruminants: A Review

      Allison, C. D. (Society for Range Management, 1985-07-01)
      Variation in voluntary forage intake is undoubtedly the major dietary factor determining level and efficiency of ruminant production. This variation is largest and least predictable for grazing ruminants. Range ruminant productivity and efficiency is relatively low due, in part, to intake limitations; therefore, productivity could probably be increased most by increasing intake. Most available literature points to digestibility and rate of ingesta passage and reticulo-rumen fill as primary mechanisms of intake regulation in range ruminants. Body size and physiological status of ruminants appear to have the largest effect of animal-related factors in governing level of voluntary intake. Kind and amount of supplementation, forage availability, and grazing intensity are major management-controlled variables affecting intake by domestic range ruminants.
    • Factors Influencing the Selection of Resting Sites by Cattle on Shortgrass Steppe

      Senft, R. L.; Rittenhouse, L. R.; Woodmansee, R. G. (Society for Range Management, 1985-07-01)
      Spatial patterns of cattle resting behavior were investigated on shortgrass steppe. Resting was divided into daytime and nighttime categories. Sites selected for daytime resting during June through August were low-lying areas, fencelines, and stock-water area. Daytime resting during September through May occurred on south-facing slopes and lowland areas. Degree of use of warm slopes varied from month to month, peaking in midwinter. A significant portion of daytime resting occurred near water (23%) and fencelines (27%) at all times of the year. Resting at night during October through May occurred on south-facing slopes, low-lying areas, sites with sandy soils, and sites with high buffalo grass (Buchloe dactyloides) cover. During June through September, cattle preferred sites on east-facing slopes and on lowlands. Cattle rested near fencelines less at night than during the day. Patterns of and factors correlated to resting were different from those associated with grazing activity. Resting behavior was correlated with topographic variables, whereas previous work has shown grazing to be correlated with vegetation variables.