• In Vitro Digestibility of South Texas Range Plants Using Inoculum from Four Ruminant Species

      Blankenship, Lytle H.; Varner, Larry W.; Lynch, Gregory W. (Society for Range Management, 1982-09-01)
      Differences in the in vitro digestible dry matter (DDM) of 26 native forage species in south Texas were determined using rumen inoculum from white-tailed deer, sheep, goat, and steer. The mean DDM of all forages was significantly different for each animal species (P<.05). Deer was the most efficient overall digestor of forbs, shrubs, and prickly pear. Of the grasses sampled, the goat was the most efficient digestor with the steer second. In overall efficiency of digestion of all forages tested, the deer was highest with 52.5%, goat with 49.2%, sheep with 47.5%, and steer with 46.6%. These data indicate that caution should be exercised when using inoculum from one ruminant species to estimate DDM for another species. Certain plant species were determined to meet the TDN requirements for maintenance levels of the four ruminants.
    • Interrelationships of Huisache Canopy Cover with Range Forage on the Costal Prairie

      Scifres, C. J.; Mutz, J. L.; Whitson, R. E.; Drawe, D. L. (Society for Range Management, 1982-09-01)
      Grass production was monitored based on seasonal harvests under various canopy covers of huisache on a Coastal Prairie blackland range site during 1978 and 1979. Grass production (Y) was not decreased in 1978, compared to that on essentially brush-free areas, until huisache canopy cover (X) exceeded 30% based on the relationship, the average of Y = 2,346 + 20X - $0.62X^2. Texas wintergrass standing crop apparently increased as huisache canopy cover increased to 25%, and its growth during winter partly compensated for standing crop losses of warm season species during the winter. In 1979, the contribution of the cool-season species was masked by greater production of warm-season species. Consequently, grass production decreased with increasing huisache canopy cover according to the relationship, the average of Y = 4,047 - 14.9X - $0.29X^2. Based on the functional relationship the average of Y = a – b1X-b2X^2, coefficients of determinations (r2) ranged from 0.50 to 0.96 when estimates of annual production of grasses or production for the growing season only were regressed against huisache canopy cover.
    • Partial Defoliation Stimulates Growth of Arizona Cottontop

      Cable, Dwight R. (Society for Range Management, 1982-09-01)
      Responses of Arizona cottontop to partial defoliation were determined by removal of the terminal growing point in the latter half of July of basal culms that were in various stages of development at the time. If soil moisture was available cottontop responded well to grazing throughout its growing season. Removal of the growing point stimulated axillary shoot growth regardless of the stage of development.
    • Seasonal Dependence on Federal Forage in Colorado

      Taylor, R. G.; Bartlett, E. T.; Lair, Kenneth D. (Society for Range Management, 1982-09-01)
      Thirty-six percent of Colorado is federal land administered by the U.S. Forest Service or Bureau of Land Management, which provides approximately 2.4 million AUM's of grazing for domestic livestock. This represents 28% of the total forage resources used by the 2200 ranchers that use federal forage in Colorado. Seasonal dependence on federal forage is greatest in summer, averaging over 50%. High seasonal dependence where few viable alternative forage sources exist makes federal forage critical to Colorado ranchers. Dependence on federal forage also varies with ranch size. Dependence varies inversely with size of cattle ranches, but varies directly with size of sheep ranches.
    • Seasonal Variations in Protein and Mineral Content of Fringed Sagewort [Artemisia frigida]

      Rauzi, Frank (Society for Range Management, 1982-09-01)
      Fringed sagewort (Artemisia frigida) was collected biweekly from May 15 through October 4, 1979, from a loamy range site near Cheyenne, Wyo. Crude protein, calcium, iron, potassium, magnesium, manganese, phosphorus, sodium, and zinc were determined on the collected plant material. After July 12, leaves and flowers were stripped from the stems and analyzed separately. Crude protein and mineral concentrations in the (fringed sagewort) plant material generally decreased with the advance of the growing season. Except for phosphorus and crude protein content in the stems after late July, the nutritional value was adequate. Fringed sagewort is considered to be of minor importance but is an important forage plant for wildlife and, to a lesser extent, for livestock use.
    • Some Consequences of Competition between Prairie Dogs and Beef Cattle

      O'Meilia, M. E.; Knopf, F. L.; Lewis, J. C. (Society for Range Management, 1982-09-01)
      Competition for range herbage between black-tailed prairie dogs (Cynomys ludovicianus) and steers was evaluated in terms of the effects prairie dogs have on herbage availability and use, and steer weight gains. Pastures grazed only by steers were termed control pastures and pastures grazed by prairie dogs and steers were designated treatment pastures. Small mammals and arthropods were monitored to determine if prairie dogs influence populations of these animals. Prairie dogs decreased herbage availability, which apparently led to reduced utilization by cattle during 1977 and 1978. The influence of prairie dogs on the herbage crop did not cause a statistically significant reduction in steer weight gains. However, the lower weight gains of treatment steers amounted to market values of $14-$24/steer less than control steers. The presence of prairie dogs appears to improve herbage quality, thus partially compensating the reduction in herbage available to steers. Pastures containing prairie dogs also supported a greater biomass of small mammals. Arthropod (mainly grasshopper) biomass in August was more than three times higher in control pastures than in treatment pastures.
    • Standing Crop and Vigor of Defoliated Russian Wildrye in Southeastern Colorado

      Svejcar, Tony; Rittenhouse, Larry R. (Society for Range Management, 1982-09-01)
      Russian wildrye plants were clipped at all possible combinations of three clipping dates (April 15, May 15, June 15) at two intensities (35 and 65% harvest of current year's growth). From 1974-1977 increasing frequency and intensity of defoliations increased total biomass removed over the 4-year period. There was no trend for reduced yield over time with any clipping treatment. However, percent plant crown alive (1976-1978) and end-of-season standing crop (1978) both indicated that increasing frequency and/or intensity of defoliation decreased plant vigor.
    • Switchgrasses: Forage Yield, Forage Quality and Water-use Efficiency

      Koshi, P. T.; Stubbendieck, J.; Eck, H. V.; McCully, W. G. (Society for Range Management, 1982-09-01)
      The purpose of the study was to evaluate 3 strains of switchgrass (Panicum virgatum L.) under 3 water and 3 harvest regimes. Dry matter yields, under natural rainfall and full irrigation, averaged 2.0 and 6.7 metric tons/ha, respectively. Productivity of the 3 strains ranked G 300>HV-341>Blackwell. Yields of HV-341 and Blackwell were similar under 1, 2, or 3 harvests per year but those of G-300 were reduced by 2 or 3 harvests. Switchgrass forage contained about 10.8% crude protein (CP) and 0.23% P in late June. In November, previously unclipped forage contained 4.3% CP and 0.12% P, while that clipped twice contained 5.5% CP and 0.15% P. Maximum production was obtained with 116.5 cm of water use but maximum water use efficiency was obtained with about 85.5 cm of water use (rainfall + irrigation + soil water). The switchgrasses are adapted for use both without irrigation and when varying amounts of irrigation water are available. G-300 yielded more and produced earlier and later than the other two strains thus it may be the best choice for use for range improvement or for irrigated pastures. However, it requires careful management because it is more susceptible to overuse than the other two strains.
    • The Chemical Constituents of Sagebrush Foliage and Their Isolation

      Kelsey, Rick G.; Stephens, Jeffrey R.; Shafizadeh, Fred (Society for Range Management, 1982-09-01)
      Five foliar constituents were measured seasonally from the three subspecies of big sagebrush in Montana. Monoterpene, crude terpenoid, and crude fat levels were lowest in the spring, increased through the summer with maximum quantities at flowering or in the fall and winter months thereafter. Crude protein and total nonstructural carbohydrates were at highest concentrations in the spring, decreased in the summer, and rose again in the fall. Sagebrush foliage consists of an external and internal component. The external material is glandular secondary metabolic products, primarily terpenoids, and cuticular waxes. The internal constituents are cell-wall polymers, protein, nonstructural carbohydrates, and lipids. A 5-minute chloroform extraction of fresh whole leaves removed the external material (crude terpenoids) with minimal affect on the internal components. Steam distillation extracted the epidermal terpenoids and the internal nonstructural carbohydrates leaving the cuticular waxes and protein in the dry matter residue.
    • The Suitability of Legumes for Rangeland Interseeding and as Grasshopper Food Plants

      Hewitt, George B.; Wilton, A. C.; Lorenz, R. J. (Society for Range Management, 1982-09-01)
      Fifteen legume varieties (selections representing 7 species) which have some potential for reseeding into rangeland were evaluated in the laboratory and in the field as to their suitability as food plants for several species of rangeland grasshoppers. Varieties of alfalfa, trefoil, and cicer milkvetch were less preferred than varieties of sanfoin, sweetclover, hairy vetch, and crown vetch. Three plant varieties, alfalfa (Mandan composite-1), birdsfoot trefoil (Cree), and cicer milkvetch (Mandan Composite-2) were the least preferred of the varieties tested based on the rate of grasshopper development and weight of adults reared on the test plants, the time spent feeding during a 30-min period, and plant mortality and % leaf reduction in a field test. Alfalfa appeared to have the greatest potential for reseeding on arid rangeland sites. Nonpreference is the main resistance factor that should be used when screening rangeland plants for grasshopper feeding preferences.
    • Training Needs for Quantifying Simulated Diets from Fragmented Range Plants

      Holechek, Jerry L.; Gross, Bryan (Society for Range Management, 1982-09-01)
      A procedure is described that results in rapid training of observers for microhistological analysis. Observers trained using this procedure were able to evaluate accurately 6 hand-compounded diets comprised of semidesert plant species. The accuracy of microhistological analysis was examined by using the 4 trained observers to evaluate 26 additional hand-compounded diets containing various combinations of 30 different grasses, forbs, and shrubs from semidesert range. The relationship between relative density (estimated percent by weight composition) and actual percent by weight composition was close to unity for species in each forage class individually or in combination. However this relationship would probably have been different if the observers had not used known diets to evaluate their accuracy and make corrections. It is recommended that all technicians using microhistological analysis regularly check their accuracy with hand-compounded diets.
    • Two-step Sampling Technique for Estimating Standing Crop of herbaceous Vegetation

      Anderson, D. M.; Kothmann, M. M. (Society for Range Management, 1982-09-01)
      Standing crop of vegetation may be estimated by sampling foliar cover per unit area and then determining mass per unit of cover. Multiplying foliar cover per unit area by mass per unit of cover gives mass per unit area (standing crop). By this method standing crop is estimated rapidly with low variance while minimizing the amount of actual harvesting required. Standing crop of both major and minor species can be estimated adequately without over sampling major species and under-sampling minor species. The technique is most easily applied to herbaceous plant communities of low stature.
    • Use of Historical Yield Data to Forecast Range Herbage Production

      Hanson, C. L.; Wight, J. R.; Smith, J. P.; Smoliak, S. (Society for Range Management, 1982-09-01)
      An analysis of the 51-year herbage yield series from the Many-berries Range Experimental Farm in southeastern Alberta showed that there was a slight dependency between current year's herbage yield and previous year's yield. The analysis showed that the conditional probability of a below-average yield following a below-average yield year was about the same as the unconditional probability of having a below-average yield in any given year. The conditional probability of an above-average yield following a year with a below-average yield was significantly below the unconditional probability of having an above-average yield in any year. The probability of an above-average yield following a year with an above-average yield was significantly greater than the unconditional probability.
    • Waterponding for Increasing Soil Water on Arid Rangelands

      Tromble, John M. (Society for Range Management, 1982-09-01)
      Ponding dikes constructed to slow and control the overland flow of runoff water were evaluated. Infiltration and runoff measurements from a sprinkling infiltrometer indicated no differences between the control and the water ponding area. Examination of 20 years of precipitation records for June through September showed that enough ponding events occurred to supply an adequate amount of water for wetting the soil profile to below the plant rooting zone. The control areas were low in available soil water even immediately following precipitation events.
    • Wind Erosion Curtailed by Controlling Mesquite

      Gould, Walter L. (Society for Range Management, 1982-09-01)
      A sand-dune mesquite area with very little interdunal vegetation was treated aerially one to three times with 2,4,5-T at 0.56 kg/ha in an oil:water emulsion. Four and five years after the initial treatment, the amount of blowing soil was evaluated using sandtraps located at various distances from the boundary between sprayed and unsprayed mesquite. The amount of wind-blown particles was greatly reduced on the area chemically treated to control mesquite. During the windy season the amount of blowing soil in the unsprayed area was more than 15-fold greater than at 180 m into the sprayed area. Intermediate amounts were measured between the boundary and 180 m into the treated area.