• Whitelined Sphinx Moth Larvae on Rangeland Vegetation

      Mock, D. E.; Ohlenbusch, P. D. (Society for Range Management, 1981-09-01)
      Larvae of whitelined sphinx [Hyles lineata (Fab.)] caused heavy defoliation and other injury to several species of range plants in a newly seeded stand of brome grass [Bromus inermis Leyss.] near Lakin, Kearny County, Kansas. Although larvae of this species are rather general feeders on broadleafed plants, they had a sequence of preference and completely ignored the brome grass. Species commonly eaten included prairie evening-primrose [Oenothera albicaulis (Pursh)] and spotted beebalm [Monarda punctata L.]. It is conjectured that feeding by whitelined sphinx larvae may sometimes influence the composition of range plant communities on the short grass prairie of the North American Great Plains.
    • Variation of Monoterpenoid Content among Subspecies and Accessions of Artemisia tridentata Grown in a Uniform Garden

      Welch, B. L.; McArthur, E. D. (Society for Range Management, 1981-09-01)
      We discovered that the midwinter monoterpenoid (volatile or essential oils) content of A. tridentata is under genetic control. We base this conclusion on the results of our study which demonstrated that some accessions of A. tridentata, grown under uniform conditions, contained significantly higher levels of monoterpenoids than others. The relationship between monoterpenoids, digestion, and palatability has not yet been conclusively demonstrated. If monoterpenoids interfere with digestion or have a negative impact on palatability, breeding and selection schemes can be developed to capitalize on the significant variation that exists among accessions of A. tridentata. Superior strains of A. tridentata could then be developed for use on mule deer winter ranges.
    • Total Nonstructural Carbohydrate Trends in Bluebunch Wheatgrass Related to Growth and Phenology

      Daer, T.; Willard, E. E. (Society for Range Management, 1981-09-01)
      Total nonstructural carbohydrates (TNC) levels in the roots and root crowns of bluebunch wheatgrass (Agropyron spicatum) were analyzed throughout the 1974 growing season. Reserves in root crowns were consistently higher than those in roots, except for the November sample when reserves were similar. The low point in TNC reserves occurred during rapid spring growth when 29% of the vegetative growth was completed and the average leaf length was 13 cm. Highest levels were attained in the late boot stage when average leaf length was 30 cm and 67% of current vegetative growth was completed.
    • Tiller Length vs. Tiller Weight: Applications to Plant Growth Studies

      Sharrow, S. H. (Society for Range Management, 1981-09-01)
      The growth and development of individual grass tillers is frequently monitored in intensive studies of plant response to treatments or environmental parameters. Since growth may be recognized as an increase in tiller weight or tiller length over time, knowledge of the relationship between them is important if researchers are to select the measure most appropriate for their needs. To make these comparisons, the mean weight and length of tillers from perennial ryegrass (Lolium perenne L.), colonial bentgrass (Agrostis tenuis Sibth.), softchess (Bromus mollis L.), and annual fescue (Vulpia Spp.) were measured on each of seven dates during the spring growing period, 1977. Sample sizes required to estimate mean tiller length were calculated on each date using Stein's two-stage procedure. The relationship between mean tiller weight and mean tiller length over time was evaluated by least squares analysis of a linear regression model. Results of these analyses indicated that mean tiller length can be estimated satisfactorily from a substantially smaller sample size than can mean tiller weight. In addition, a strong linear relationship was observed between mean tiller weight and mean tiller length over time. The strength and linear nature of this relationship suggests that both measures will yield similar relative growth curves when sequential observations are plotted over time. Actual growth curves plotted for perennial ryegrass and colonial bentgrass support this supposition. Therefore, since tiller lengths require a small sample size to estimate each mean, both time and money can be saved by basing growth analysis on observations of tiller length rather than on tiller weight.
    • The Economic Effects of Three Changes in Public Lands Grazing Policies

      Torell, A.; Garrett, J. R.; Ching, C. T. K. (Society for Range Management, 1981-09-01)
      Linear programming was used to analyze the impact of potential changes in federal policies. The amount of federal grazing used by ranchers was found to be relatively unresponsive to grazing fee increases. However, allotment reductions and adjustments in the allowed season of use for federal grazing had a large impact on the quantity of beef supplied and the net income of the ranches studied.
    • Sodium Monofluoroacetate (1080): Relation of Its Use to Predation on Livestock in Western National Forests, 1960-78

      Lynch, G. W.; Nass, R. D. (Society for Range Management, 1981-09-01)
      Concern over certain animal damage control methods used by the U.S. Fish and Wildlife Service (USFWS), primarily the predacide Compound 1080, prompted a Presidential Order in 1972 banning the use of toxicants on public lands. This continuing ban of 1080 use has been reinforced by the recent policy address issued by the Secretary of the Interior. Following the initial ban, greater emphasis was placed on aerial hunting of coyotes for prevention and correction of damage to sheep and goats. Aerial hunting is expensive, however, and has only limited application in timbered, mountainous areas of many national forests. In the period since toxicants were banned, number of grazing livestock reported as lost to predation on western national forests has increased. Numbers of toxic bait stations (1080) used throughout the West, from 1960 until the 1972 ban, showed a strong inverse relationship with numbers of livestock reported lost to predation on national forests during these same years.
    • Seasonal Food Preferences of Cattle on Native Range in the South Texas Plains

      Everitt, J. H.; Gonzalez, C. L.; Scott, G.; Dahl, B. E. (Society for Range Management, 1981-09-01)
      Cattle diets were studied on a predominantly native range in Hidalgo County, which is in the extreme southern part of Texas, from September, 1976, to November, 1977. Microhistological examination of cattle feces was used to determine the botanical composition of diets. Percentages of grasses, forbs, and browse consumed by cattle for the fall of 1976 and the winter, spring, summer, and fall of 1977, respectively, were: grasses-77.9, 81.2, 84.9, 65.1, 63.6; forbs-20.2, 6.9, 13.4, 31.6, 34.8; and browse-2.0, 11.9, 1.7, 3.3, 1.6. Cattle showed an increasing preference for forbs during the summer and fall of 1977 as the availability of several grass species decreased. Roemer three-awn, red lovegrass, and hooded windmillgrass were the most utilized species, but they were eaten in about equal proportion to their availability. Buffelgrass, common Bermudagrass, and sedges were eaten in lesser amounts but were highly preferred. Perennial forbs, especially spreading sida and orange zexmenia were important components of the summer and fall diets. Pricklypear was the only important browse species which was important only in winter. These data indicated that perennial grasses made up the bulk of cattle diets on a predominantly native range in south Texas; however, perennial forbs were important seasonally.
    • Relative Palatability of Seven Artemisia Taxa to Mule Deer and Sheep

      Sheehy, D. P.; Winward, A. H. (Society for Range Management, 1981-09-01)
      Relative preference for seven important sagebrush taxa in Oregon was established for mule deer and domestic sheep. Mule deer showed highest preference for low sagebrush (Artemisia arbuscula ssp. arbuscula), mountain big sagebrush (A tridentata ssp. vaseyana), foothill big sagebrush (a recently recognized variant of mountain big sagebrush) and Bolander silver sagebrush (A. cana ssp. bolanderi). They showed intermediate preference for basin big sagebrush (A. tridentata ssp. tridentata) and Wyoming big sagebrush (A. tridentata ssp. wyomingensis) and least preference for black sagebrush (A. nova). Sheep showed highest preference for low sagebrush and medium preference for black sagebrush. They utilized but did not prefer, Bolander silver sagebrush and mountain and foothill big sagebrush and they showed least preference for Wyoming and basin big sagebrush. Genetic variation between kinds of sagebrush taxa influenced animal preference more than environmental variation within a taxon.
    • Plant Development, Stage of Maturity and Nutrient Composition

      Kilcher, M. R. (Society for Range Management, 1981-09-01)
      Declining nutrient content of native and seeded pasture plants with advancing growing stages are discussed. All plant types display this regression in nutritive value but to different degrees, different rates, and varying patterns. The situation is further aggravated by the concomitant increase in lignin and other fibrous properties which precludes maximum digestibility of an already declining nutrient level in the plant.
    • Mineral Supplementation of Cattle Grazing Improved Pastures in the Thai Highlands

      Falvey, J. L.; Gibson, T. A. (Society for Range Management, 1981-09-01)
      The estimated liveweight gains of cattle grazing an improved pasture based on Desmodium intortum while receiving a mineral supplement were compared with the liveweight gains of cattle not receiving a supplement. Liveweight gains of cattle on the two treatments did not vary significantly over 1 year, and the liveweight gains recorded of 108 g hd-1 day-1 for a mixed herd and 230 g hd-1 day-1 for young stock over 1 year are suggested to be suitable for use in development-planning budgets.
    • Mineral Content in Creeping Bluestem as Affected by Time of Cutting

      Kalmbacher, R. S.; Martin, F. G. (Society for Range Management, 1981-09-01)
      Florida's soils are low in nutrients, which is reflected in the low mineral content of range forages. This investigation was designed to determine the contents of P, K, Ca, Mg, Fe, Mn, Zn, and Cu and the Ca: P ratio in creeping bluestem (Schizachyrium stoloniferum Nash.), a widespread, high-yielding native forage. The grass was cut at 10 and 20-cm heights during 70-day intervals from June to October 1976, August to December 1976, and October 1976 to February 1977. Height of cut did not have significant effect on mineral contents, but strong seasonal patterns occurred. Based on whole plant samples, the contents of K, Mg, P, Zn, and Cu and the Ca: P ratio were inadequate when compared to National Research Council requirements for dry, pregnant cows, but Ca, Fe and Mn may be adequate in the forage.
    • Microwave Drying of Rangeland Forage Samples

      Schuman, G. E.; Rauzi, F. (Society for Range Management, 1981-09-01)
      This study was conducted to compare the effectiveness of microwave drying with that of conventional forced-air oven drying of rangeland forage species. The data show that a microwave oven can dry grass forage samples for biomass production estimates without significantly affecting their nitrogen or phosphorus levels. Drying in a microwave for 10 minutes was comparable to drying in a forced air oven at 55 degrees C for 24 hours.
    • Impact of Burning Pinyon-Juniper Debris on Select Soil Properties

      Gifford, G. F. (Society for Range Management, 1981-09-01)
      Burning had the greatest impact on soils beneath burned debris piles. Electrical conductivity, phosphorus, potassium, percent nitrogen, and percent organic carbon increased significantly at all soil depths the first year after burning debris piles. No impact was evident on phosphorus, percent nitrogen, and percent organic carbon by the second year. Impacts on burned interspace areas were generally less pronounced and few impacts were measured the second year. Impact of burning on soil pH was minor.
    • Growth Response of Two Saltbush Species to Nitrate, Ammonium, and Urea Nitrogen Added to Processed Oil Shale

      Richardson, S. G.; McKell, C. M. (Society for Range Management, 1981-09-01)
      Nitrate nitrogen promoted good growth of cuneate saltbush (Atriplex cuneata) and gardner saltbush (A. gardneri) on processed oil shale in a glasshouse pot experiment but ammonium and urea nitrogen were not utilized effectively in growth.
    • Germination Requirements of Lotebush (Ziziphus obtusifolia var. obtusifolia)

      Speer, E. R.; Wright, H. A. (Society for Range Management, 1981-09-01)
      Optimum average temperatures for germination of lotebush (Ziziphus obtusifolia var. obtusifolia) seeds in the laboratory were 20 degrees to 30 degrees C. Although some germination occurred without light and without a cold treatment, both of these factors tripled germination when they were present. Aging was unnecessary to obtain optimum germination. Best emergence in the field occurred when average soil temperatures ranged from 22.4 degrees to 27.1 degrees C. These field temperatures are most common in early spring and early fall. Litter enhanced germination in late spring and summer. Timing of precipitation is a limiting factor during the warmest months.
    • Forage Production on Important Rangeland Habitat Types in Western Montana

      Mueggler, W. F.; Stewart, W. L. (Society for Range Management, 1981-09-01)
      Peak standing crop and its variability were evaluated over a 3-year period on 35 sites representing 13 important grassland and shrubland habitat types in western Montana. Average production ranged from slightly over 600 kg/ha on the least productive habitat type to 2,900 kg/ha on the most productive. Good sites seldom produced more than twice as much as poor sites within the same habitat type. Although as much as 2 1/2 times more herbage was produced on a site during the high year than during the low year, the maximum yearly difference for all sites averaged only 1 1/2 times greater. Variation of vegetation classes and factors contributing to production differences are discussed.
    • Effects of Livestock Grazing on Infiltration and Erosion Rates Measured on Chained and Unchained Pinyon-Juniper Sites in Southeastern Utah

      Busby, F. E.; Gifford, G. F. (Society for Range Management, 1981-09-01)
      This study was conducted on sandy loam soils in southeastern Utah during summers of 1971 and 1972. Forage removal and soil compaction had no consistent effect on infiltration rates. However, the clipping and compaction were an instantaneous application of forage removal and soil pressure and thus may not adequately represent long term, accumulative conditions imposed by actual grazing. Areas rested from livestock grazing since 1967 had significantly higher infiltration rates than grazed areas on unchained woodland and chained, debris-in-place sites. Grazed plots had infiltration rates comparable to rates measured on areas protected from grazing since 1969 or 1971. Grazing did not consistently affect infiltration measured on chained, debris-windrowed sites. Infiltration rates increased on all sites as the period of rest from grazing increased. None of the 21 soil and vegetation variables included in this study were identified by multiple regression models as consistently explaining significant amounts of variation in infiltration rates. Interrill or sheet erosion rates were not significantly affected by forage removal subtreatments. No consistent relationship between erosion rates and soil compaction subtreatments or various periods of rest from grazing was found.
    • Economic Comparison of Honey Mesquite Control Methods with Special Reference to the Texas Rolling Plains

      Whitson, R. E.; Scifres, C. J. (Society for Range Management, 1981-09-01)
      Although economic responses to honey mesquite control varied considerably within and among resource regions in Texas, aerial applications of herbicides generally produced higher annual rates of return on the investment than did mechanical alternatives. Statewide, aerial applications of 2,4,5-T produced the greatest annual rates of return, averaging 15.7% for deep range sites and 11.0% for shallow range sites for projected livestock responses when cattle prices were estimated to average $0.97/kg ($44.00/cwt, 1978 dollars). Statewide, annual rates of return from aerial application of herbicides for honey mesquite control on shallow sites (statewide) varied from -8.3% to 18.1%, based on the $0.97/kg livestock price. When cattle prices were varied from $0.82/kg ($37.00/cwt) to $1.05/kg ($47.50/cwt), annual rates of return from aerial application of 2,4,5-T to deep sites on the Rolling Plains and Rolling Red Plains of Texas ranged from 9.6% to 17.9%. Chaining of honey mesquite on deep sites of the Rolling Plains and Rolling Red Plains produced rates of return from 7.1% to 12.5%. While the economic feasibility of herbicides in general was determined to be greater than that from the use of mechanical practices, rates of return from herbicides are more price sensitive than mechanical treatments. Over the 20-year planning period, tame pastures in the Rolling Plains produced the greastest accumulated net present value ($/ha) when the annual interest rate charged to the added investment was 5% or less. When the annual interest rate was 7% or 9%, the net present values of herbicide treatments exceeded those of the mechanical methods.
    • Ecology of Germination and Flowering in the Weedy Winter Annual Grass Bromus japonicus

      Baskin, J. M.; Baskin, C. C. (Society for Range Management, 1981-09-01)
      From the time of seed maturity in late June and early July until December when temperatures drop to near freezing, habitat temperatures are within the range of those required for germination of seeds of the winter annual Bromus japonicus. However, a large proportion of the seeds in a given seed crop fail to germinate in the autumn of the year in which they are produced because they are not dispersed until winter. A high percentage of of the winter-dispersed seeds is induced into dormancy and must undergo a period of afterripening the following summer before germination can occur the next autumn. Thus, many of the plants that become established at a population site in autumn are from the previous year's seed crop. Plants overwinter in the field as "rosettes" and require long days for flowering. Nonvernalized plants exposed to natural short photoperiods of late autumn and winter flower under long days in spring, but plants flower much sooner if they are subjected to both low temperatures (vernalization) and short photoperiods during winter.