• Value of Black Hills Forest Communities to Deer and Cattle

      Kranz, J. J.; Linder, R. L. (Society for Range Management, 1973-07-01)
      Aspen, pine, and mixed aspen-pine communities were studied at three different locations in the Black Hills National Forest of South Dakota from 1968 to 1970. Overstory densities were greatest in pine with a basal area (diameter at breast height) of 180.5 ft2 per acre. Aspen-pine had 133.6 ft2 per acre and aspen 89.5 ft2 per acre. Understory production was inversely related to overstory density with 590 lb/acre air-dried forage in aspen, 415 lb/acre in mixed aspen-pine, and 215 lb/acre in pine. Aspen communities appeared to represent better feeding areas for both deer and cattle than mixed aspen-pine or pine. However, use by white-tailed deer, estimated by pellet group density, was greatest in mixed aspen-pine. Cattle use, estimated by chip density, was greatest in aspen and least in pine.
    • Value of Broom Snakeweed as a Range Condition Indicator

      Jameson, D. A. (Society for Range Management, 1970-07-01)
      Following an initial 13 year stabilization period, changes in broom snakeweed populations on southwestern pinyon-juniper ranges were investigated over a subsequent 13-year period. The changes which occurred appeared to be the result of oscillating populations rather than of range condition.
    • Value of Indian Ricegrass in Range Reseeding

      Verner, J. E. (Society for Range Management, 1956-09-01)
    • Value of mountain rye for suppression of annual bromegrasses on semiarid mined lands

      Andersen, M. R.; Depuit, E. J.; Abernethy, R. H.; Kleinman, L. H. (Society for Range Management, 1992-07-01)
      The value of mountain rye (Secale montanum Guss.) for competitive suppression of 2 annual bromegrasses (downy brome, Bromus tectorum L. and Japanese brome, B. japonicus Thunb) was investigated in a 3-year study on reclaimed coal mined lands in southeastern Montana. Rye established rapidly and vigorously, but did not persist appreciably (either through initially established plants or new seedlings) after the second year. However, mountain rye significantly reduced growth and reproduction of annual bromes during the first 2 growing seasons. Mountain rye also inhibited growth of other concurrently seeded perennial grasses during the first 2 seasons. Annual brome soil seedbanks were not sufficiently reduced in rye-seeded plots to prevent an eventual, third year recovery of brome productivity after a massive dieback of rye between the second and third growing seasons. Mountain rye therefore proved effective for short but not for longer-term control of annual bromes. This study did not allow distinction between the known short-lived nature of mountain rye and/or local environment as causal factors for the massive dieback after the second year.
    • Value of multiple fecal indices for predicting diet quality and intake of steers

      Leite, E. R.; Stuth, J. W. (Society for Range Management, 1990-03-01)
      The relationship of fecal nitrogen fractions and condensed tannins dietary crude protein, in vitro organic matter digestibility, and intake of steers was assessed to determine the suitability of these multiple fecal indices for predicting quality of animal diets under free-roaming conditions. Research was conducted on the Texas A&M Native Plant and Animal Conservancy near College Station, located in the Post Oak Savannah region of Texas. Regression equations were used to evaluate relationships between dietary intake and quality to fecal variables. Dietary crude protein, digestible organic matter, organic matter intake, crude protein intake, and digestible energy intake were determined from previous studies. Corresponding fecal samples were analyzed for absolute output, proportions, and concentrations of nitrogen and selected fractions of fecal organic matter, as well as fecal condensed tannins, proportions of fecal monocot and dicot fragments, and fecal organic matter. In general, no fecal parameter by itself had a high correlation with dietary variables when expressed on a proportion or concentration basis. A combination of fecal indexes accounted for more variation in dietary parameters than fecal nitrogen. Fecal nitrogen fractions did not improve the predictive power of multiple variable models. Equations predicting dietary crude protein (%) and crude protein intake yielded the highest coefficients of determination (R2 = .57 and .51, respectively). Multiple fecal indices used in this study were of limited value in predicting diet quality and intake.
    • Values of Four Communities for Mule Deer on Ranges with Limited Summer Habitat

      Austin, D. D.; Urness, P. J. (Society for Range Management, 1985-03-01)
      Four plant communities were evaluated from May through September for mule deer dietary and nutritional values. The communities were dominated by Utah serviceberry, Gambel oak, big sagebrush, and mixed browse. In early summer deer diets contained many browse and forb species and were high in crude protein, but as summer progressed fewer species were selected and dietary crude protein declined, especially in the big sagebrush and serviceberry communities. Thus late summer was determined the critical period for forage quality. Range conditions were reflected by body size and condition of deer in fall.
    • Valuing grazing use on public land

      Bartlett, E. T.; Torell, L. A.; Rimbey, N. R.; Van Tassell, L. W.; McCollum, D. W. (Society for Range Management, 2002-09-01)
      The value of public land forage has been of key interest since grazing fees were first established on federal lands. Additionally, knowing the value of rangeland forage is important for assessing the economics of range improvements, grazing systems, and alternative land uses. It is important for resource value comparisons and impact assessments when public land forage is allocated to other uses. In this synthesis paper, we review the various methods that have been used to value public land forage and discuss the advantages and limitations of each. We highlight that past valuation efforts have concentrated on the value of public land forage for livestock production and, consequently, underestimated total forage value and rancher willingness to pay for forage and grazing permits. These research efforts failed to recognize that amenity and lifestyle attributes from ranch ownership and forage leasing play important roles in the use and pricing of rangeland forage. We review the numerous studies conducted to estimate public land forage value and suggest modifications to improve future value estimates. Because lifestyle attributes of ranch ownership have so strongly influenced ranch values and what ranchers are willing to pay for grazing use on public lands, we find the market value of federal grazing permits and a modification of the standard contingent valuation method for valuing non-market goods to hold the greatest promise for valuing public land grazing.
    • Variability for Ca, Mg, K, Cu, Zn, and K/(Ca + Mg) ratio among 3 wheatgrasses and sainfoin on the southern high plains

      Kidambi, S. P.; Matches, A. G.; Griggs, T. C. (Society for Range Management, 1989-07-01)
      The objective of this study was to determine the variability of Ca, Mg, K, Cu, Zn, and K/(Ca+Mg) ratio in 'Jose' tall wheatgrass [Thinopyrum ponticum (Podp.) Barkw. & D.R. Dewey], 'Luna' pubescent wheatgrass [T. intermedium subsp. barbulatum (Schur.) Barkw. & D.R. Dewey], and 'Hycrest' crested wheatgrass [Agropyron cristatum (L.) Gaertn. × A. desertorum (Fisch. ex Link.)]. Each grass was grown alone and in paired rows with 'Renumex' sainfoin (Onobrychis viciifolia Scop.) on a Pullman clay loam soil (a fine, mixed thermic Torrertic Paleustoll). Each species or mixture was evaluated under 3 cutting schedules in 1985 and 1986 and their mineral concentrations were compared to the recommended daily requirements of beef cattle. The concentration of minerals was similar in grasses grown as monocultures and in binary mixtures. The concentrations of all minerals and the ratio varied with harvest time, phenological stage, and year. Therefore, seasonal dynamics of mineral concentrations should be kept in mind when evaluating the mineral status of different forages. Among grasses, Hycrest had a better mineral profile for beef cattle than Luna or Jose. Sainfoin had higher concentrations of Ca, Mg, Cu, and Zn and much lower K/(Ca+Mg) ratio than the grasses. Hence, sainfoin-Hycrest mixtures may provide mineral concentrations more in balance with beef cattle requirements and help alleviate the problem of hypomagnesemia.
    • Variability for seed size and yield in two tall dropseed populations

      Boe, A. (Society for Range Management, 1990-05-01)
      Tall dropseed [Sporobolus asper (Michx.) Kunth var. asper] is a drought-tolerant, perennial, warm-season grass that has potential for forage and soil conservation purposes. A prairie and an adjacent roadside population from northeastern South Dakota were evaluated for seed yield and size characteristics for 3 years (1985-1987) in a space-plant nursery at Brookings, S. Dak. The objective was to obtain information on between and within population variability and intraplant variability that would provide a basis for designing a breeding program to improve seed production and quality in this germplasm. The roadside population produced significantly (P<0.01) higher seed yields and larger mean 100-seed weight than the prairie population. Percent small seed (based on screen-separation of seed yields of individual plants into small, medium, and large seed size classes) decreased significantly (P<0.01) as seed yield increased, but the volume of small seed increased concurrently with seed yield. Percent large seed increased significantly (P<0.01) with increased seed yield and mean seed size. Highly significant (P<0.01) differences were found among years for seed yield and mean seed size, but all plants produced seeds of each size class each year. Inter- and intrapopulation genetic variability was indicated for yield of the large seed size class. Screen-separation of individual plant seed yields could be used to identify superior genotypes to be used in the development of a cultivrr that produces a high percentage of large seed.
    • Variability in germination rate among seed lots of Lehmann lovegrass

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

      Bryant, F. C.; Kothmann, M. M. (Society for Range Management, 1979-03-01)
      Biomass estimates were made with regression techniques using crown volume and weight relationships. The log-log function yielded the highest coefficient of determination for Vasey shin oak, plateau oak, Texas persimmon, and honey mesquite. A quadratic function was best for wollybucket bumelia, littleleaf sumac, agarito, and pricklyash. Sugar hackberry showed equally high coefficients with either the linear or quadratic. Coefficients of determination for catclaw acacia, elbowbush, and skunkbush sumac generally were low regardless of the type of regression equation used. When sampled at various periods over the year, predictive accuracy declined for Vasey shin oak and plateau oak through fall and winter but rose again in spring and early summer. For both species, the log-log function was best from late summer to winter but during spring and early summer the quadratic function was best.
    • Variability of crude protein in crested wheatgrass at defined stages of phenology

      Angell, R. F.; Miller, R. F.; Haferkamp, M. R. (Society for Range Management, 1990-05-01)
      Variability of crude protein concentration in crested wheatgrass (Agropyron desertorum (Fisch. ex Link) Schult) is an important consideration in the development of grazing programs. Crude protein (CP) concentration in crested wheatgrass was monitored at specific stages of phenology for 5 years. During that time September through August precipitation varied from 68 to 142% of the 37-year mean. Vegetation was clipped once at 10 phenological stages beginning in April. At the last clipping date, in mid-August, regrowth accumulated after prior clippings was collected. Over the 5-year period, CP of vegetation clipped during mid vegetative growth in late April varied 35%, relatively, from 14.7% in 1983 to 9.5% during 1985. Even though 1984 crop year precipitation exceeded 1983 by 84 mm, maximum topgrowth biomass was 449 kg/ha lower in 1984. Also, CP percentage of vegetative growth in April was 1.8% lower in 1984 than in 1983. Regrowth CP was positively correlated (r=0.98) with June precipitation, and with the number of rain events in July (r=0.97). Plants clipped in the boot stage had greater forage CP in August than plants clipped prior to boot stage. However, regrowth biomass was affected by soil water availability and was highly variable. Crude protein in vegetative growth was marginal for growing steers in 1985. Although growing stock are often supplemented in late summer, these data are interpreted to show that spring supplementation may be needed some years.
    • Variability of Infiltration within Large Runoff Plots on Rangelands

      Devaurs, M.; Gifford, G. F. (Society for Range Management, 1984-11-01)
      In this study we investigated the variability of infiltration on native rangeland sites. A rainfall simulator was used to collect data on runoff from small (0.37 m2) plots located within large plot boundaries (32.5 m2). Three range sites were sampled and data were collected from unfenced, fenced, and rototilled conditions on each site. In addition data were collected on vegetation, antecedent moisture, bulk density, soil texture, and organic matter as possible explanations for variations in hydrologic response on small and large plots. The field study demonstrated large variability in measured infiltration and soil physical properties on relatively uniform rangeland sites, suggesting that inherent variability patterns need to be examined to provide appropriate confidence intervals for single parameter values that may be applied to larger areas. No set of factors consistently explained the observed variability within large plots.
    • Variability of Miserotoxin Concentration in Timber Milkvetch

      Majak, W.; McLean, A. (Society for Range Management, 1975-09-01)
      The variability in miserotoxin concentration of 120 individual timber milkvetch plants was determined in the bud, flower, and pod stages of growth on rough fescue grassland, parkland, and Douglasfir zone locations. Although a broad dispersion in miserotoxin levels was evident within each sampling unit of ten plants, the grassland samples exhibited the greatest toxicity with an exceptional level (10.17 +/- 1.13%) occurring during the bud stage. The bud stage of the parkland samples yielded intermediate concentrations (5.22 +/- 1.18%) while forest plants contained lower miserotoxin levels (4.08 +/- 0.95% to 2.49 +/- 0.47%). A decline in miserotoxin levels occurred during the bud-to-pod interval at the grassland and parkland sites, but significant differences were not apparent between the progressive stages of growth at the forest locations. The timber milkvetch toxicity patterns based on the variability of individual plants confirmed previously described trends derived from composite sampling.
    • Variability of near-surface soil temperature on sagebrush rangeland

      Pierson, F. B.; Wight, J. R. (Society for Range Management, 1991-09-01)
      Models used to simulate plant growth and insect development on rangelands often assume that soil temperature is homogeneous over the entire area of interest. This simplifying assumption is made because few data are available on the magnitude and structure of the spatial variability of soil temperature within rangeland communities. The influence of sagebrush on the spatial variability and diurnal fluctuations of near-surface soil temperature was examined within a sagebrush-grass plant community. Hourly soil temperatures were measured at 1-, 5-, and 10-cm depths at 30-cm intervals along a 12.3-m north-south transect over a 6-day period in March, 1989. Both classical and geostatistical techniques were used to quantify and model the magnitude and structure of the spatial and temporal variability. Maximum soil temperatures at the 1-cm depth varied from 7 to 23 degrees C under sagebrush and bare interspace, respectively. Periodic spatial patterns in soil temperature were found for all measured depths with a wavelength of periodicity approximately equal to the separation distance between sagebrush plants along the transect. Diurnal variability in near surface soil temperature was much greater in interspace areas compared to under sagebrush plants. The amplitude of diurnal variability in soil temperature at the 1-cm depth under sagebrush was similar to the amplitude of the diurnal variability at the 10-cm depth within the interspaces.
    • Variability within a native stand of blue grama

      McGinnies, W. J.; Laycock, W. A.; Tsuchiya, T.; Yonker, C. M.; Edmunds, D. A. (Society for Range Management, 1988-09-01)
      Considerable variability and patchiness have been observed within sites of native range dominated by blue grama [Bouteloua gracilis (H.B.K.) Griffiths] range at the Central Plains Experimental Range, Weld County, Colorado. Patches containing tall plants of blue grama with many seedstalks were interspersed with patches of short plants with few seedstalks. Differences in plant height were not entirely related to soil properties. Relative differences in plant height among plants collected in the field were maintained when these plants were grown in a greenhouse environment. "Dry spots" (usually 2 to 4 m in diameter) that contain dark-colored, wilted plants have also been observed during dry, hot weather. We found several differences in soil properties that could be responsible for the dry spots. All differences in soil properties were within the range for the soil series of the experimental site, an Ascalon fine sandy loam (Aridic Argiustoll). Sixty-two plants of blue grama were collected based on their variability from a single pasture, increased vegetatively in the greenhouse, and transplanted into a spaced-plant nursery. In the third growing season following transplanting, mean values for measurements on replicated clones ranged from 202 to 719 reproductive culms per ramet, 25 to 46 cm height of reproductive culms, 17 to 24 cm basal diameter, 39 to 93 grams dry matter per ramet, and from 11 June to 20 July for first anthesis. Somatic chromosome numbers were determined for 60 plants and 55 were tetraploids (4x = 40), 3 were pentaploids (5x = 50), and 2 were hexaploids (6x = 60). We concluded that the observed variability and patchiness apparently result from a combination of both genetic and edaphic factors.
    • Variable Germination Response to Temperature for Different Sources of Winterfat Seed

      Moyer, J. L.; Lang, R. L. (Society for Range Management, 1976-07-01)
      Superior sources of winterfat seed for range revegetation should be sought, but a clearer concept of what constitutes a "superior" type is necessary. Laboratory germination temperature response of seed collected from three sources was determined. Some positive reactions to 5 degrees C prechilling were observed 13-16 weeks after collection. When the same seedlots were subjected to constant temperatures of 5 degrees C, 10 degrees C, and 20 degrees C, seed from plants originating at the lower elevations (Simla, Colorado and Pine Bluffs, Wyoming) germinated best at the lower temperatures, unlike seed collected from a Laramie, Wyoming source. Kinetic studies of germination verified that rates varied among the seedlots, but were not associated with differences during any particular stage of germination. Different temperature responses between seedlots could have practical implications regarding stand establishment.
    • 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.
    • Variation in Defecation Rates of Pronghorns Relative to Habitat and Activity Level

      Irby, L. R. (Society for Range Management, 1981-07-01)
      During June through September, 1977, pronghorn antelope (Antilocapra americana) were observed in the National Bison Range, Moiese, Montana, to determine if defecation rates were constant in different habitat types and at different levels of activity. Individuals and groups that were active 50% or more of observation periods were found to have defecation rates approximately 10 times greater than groups or individuals that were active less than 50% of observation periods. Habitat type was much less tightly related to defecation frequency than was activity level.