• 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.
    • Technique to Separate Grazing Cattle into Groups for Feeding

      Karn, J. F.; Lorenz, R. J. (Society for Range Management, 1984-11-01)
      A training procedure is described which was used to separate a group of cattle grazing the same pasture into smaller groups to facilitate supplementation. The procedure was successfully used to make 3 separations and probably could be used for 1 or 2 more. It appears to be a useful alternative to maintaining supplementation groups on separate pastures.
    • Soil, Vegetation, and Hydrologic Responses to Grazing Management at Fort Stanton, New Mexico

      Gamougoun, N. D.; Smith, R. P.; Wood, M. K.; Pieper, R. D. (Society for Range Management, 1984-11-01)
      The purpose of this study was to evaluate vegetation, soils, infiltration rates, and sediment production as they relate to livestock exclusion, continuous heavy grazing, continuous moderate grazing, and rotation grazing on a homogeneous plant-soil complex. The exclusion of livestock resulted in infiltration rates significantly higher than when the pastures were grazed in any system. No differences were found between heavily and moderately stocked pastures. This was attributed to organic matter additions from forbs that replaced grasses when the area was heavily grazed. The rotation treatment had infiltration rates that were lower than the exclosures or continuous grazing treatments. Sediment production from interrill erosion was similar in all treatments except when the livestock were concentrated into a fourth of the rotation system's area, which resulted in higher sediment levels.
    • Short-Term Vegetation Responses to Fire in the Upper Sonoran Desert

      Cave, G. H.; Patten, D. T. (Society for Range Management, 1984-11-01)
      Annual and perennial plant vegetation was sampled following a controlled burn (1981) and a wildfire (1980) in the Upper Sonoran Desert near Phoenix, Ariz. Perennial plant composition 1 year after controlled burning included 32% shoot survivors, 30% sprouters, and 38% seeders, mostly brittle bush (Encelia farinosa1). Several invader species, stickweed (Stephanomeria exigua) and four o'clock (Mirabilis bigelovii) were important seeders, indicating that there may be postfire successional communities in the Upper Sonoran Desert. Most cacti were fire killed or died eventually from fire damage. Total annual plant density decreased (69%) while biomass increased significantly (131%) on burned areas. Red brome (Bromus rubens) was essentially eliminated 1 year after fire while schismus (Schismus arabicus) and Indian wheat (Plantago spp.) increased in both density and biomass. Fire appears to enhance rangeland productivity in the Upper Sonoran Desert.
    • Seed Pretreatments and Their Effects on Field Establishment of Spring-Seeded Gardner Saltbush

      Ansley, R. J.; Abernethy, R. H. (Society for Range Management, 1984-11-01)
      Gardner saltbush [Atriplex gardneri (Moq.) D. Dietr.] seeds collected from the Red Desert Basin of Wyoming were subjected to pretreatments of scarification (Sc), washing (W), and stratification (St) to alleviate dormancy. Laboratory germination was evaluated. Subsequently, seedling vigor was observed by determining field emergence of similarly pretreated seeds spring planted at 1 irrigated and 2 dryland sites in Wyoming. Effects of 1-cm and 3-cm planting depths on emergence were also evaluated. Seed was pretreated, then dehydrated with minimal impact on seed germination. Field emergence was much less than laboratory germination for all treatments at all sites, indicating that establishment for this species is related to poor seedling vigor as much as to seed dormancy. Moreover, when compared to untreated controls, relative responses to seed pretreatments often differed between laboratory and field trials. In the laboratory Sc = W = St provided the greatest germination, whereas the best seed pretreatment for field establishment was Sc + St. Washing had little effect on enhancing field emergence and appeared to inhibit effects of St in scarified seed. The most effective planting depth varied with climatic/edaphic severity of the site.
    • Phenological Development and Water Relations in Plains Silver Sagebrush

      White, R. S.; Currie, P. O. (Society for Range Management, 1984-11-01)
      Detailed measurements were made on silver sagebrush plants to quantify phenological development, plant water potential, and soil water status. Measurements were made at bi-weekly intervals from early April to late October. A phenological scoring system was employed and the data used in linear regression equations with calendar date or plant water potential as independent variables. Both variables were used successfully in predicting phenological development in silver sagebrush. However, calendar date had less variability around the regression line, and it would therefore probably have greater direct application. The results should prove of value in future autecological studies of the species and will provide important information to manage plant communities that contain silver sagebrush.
    • Natural Establishment of Aspen from Seed on a Phosphate Mine Dump

      Williams, B. D.; Johnston, R. S. (Society for Range Management, 1984-11-01)
      The natural reproduction of aspen (Populus tremuloides Michx.) from seed was discovered on a phosphate mine dump in southeastern Idaho. Aspen seedlings were found growing on areas that were essentially bare except for scattered plantings of containerized shrubs and trees. Aspen survival and growth was monitored for 4 growing seasons. Seedling density varied from 2 to 10 per m2, seedling heights varied from 16 to 81 cm, and survival rate was 73% at the end of 4 growing seasons. No changes in the number of seedlings were noted after the second growing season.
    • Low Rates of Tebuthiuron for Control of Sand Shinnery Oak

      Jones, V. E.; Pettit, R. D. (Society for Range Management, 1984-11-01)
      Tebuthiuron [N-(5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl)-N,N′-dimethylurea] pellets (20% ai) were broadcast at 0.2 kg increments to 1.0 kg/ha onto a sand shinnery oak (Quercus havardii) community in west Texas (33 degrees 23′52″N and 102 degrees 46′38″W). Treatments greater than or equal to 0.4 kg/ha reduced oak canopy 98% and standing crop at least 90%. Grass yield was unaffected by herbicide treatments during the first year. Thereafter, yield on treated areas increased from 420 to 690 kg/ha as contrasted to 140 kg/ha on the control. Where oak was untreated, grasses became quiescent, due to drought, up to 6 weeks earlier than on treated areas.
    • Leaf Area, Nonstructural Carbohydrates, and Root Growth Characteristics of Blue Grama Seedlings

      Wilson, A. M. (Society for Range Management, 1984-11-01)
      Establishment of blue grama [Bouteloua gracilis (H.B.K.) Lag ex Steud.] seedlings requires extension of adventitious roots into the soil profile. The objectives of this study were to determine the effects of leaf area and total nonstructural carbohydrates (TNC) on root growth characteristics of blue grama. Seedlings supported by the seminal root only were treated with 3 days of reduced light and then with 0, 1, 2, and 3 days of full sunlight to alter TNC percentage in crowns. Seedlings within each of these treatments were then clipped at a height of 3, 6, 9, and 12 cm, or left unclipped to alter leaf area. Adventitious root growth was studied during a 3-day test. Path coefficients indicating the effects of leaf area on number of roots per seedling, depth of roots, and root weight per unit length (diameter) were 0.72, 0.47, and 0.77, respectively. The TNC had smaller effects on root growth than did seedling leaf area. Clipping treatments probably reduced root growth because of a deficiency of photosynthetic products. But, the reduction was explained by an adjustment in all components of growth rather than in root depth only. Thus, blue grama seedlings maintained a reasonable rate of root elongation even under severe clipping treatments.
    • Germination Profiles of Introduced Grasses at Six Constant Temperatures

      Martin, M. H.; Cox, J. R. (Society for Range Management, 1984-11-01)
      Seeds of A-68 Lehmann lovegrass (Eragrostis lehmanniana Nees), cochise lovegrass (Eragrostis lehmanniana Nees × Eragrostis trichophora Coss & Dur.) and A-84 and Catalina boer lovegrasses (Eragrostis curvula var. Conferta Nees) accessions were germinated for 14 days at constant temperatures of 15, 18, 21, 24, 27, and 30 degrees C. Light intensity was 216 micromol m-1 s-1 and photoperiod was 15 h. Germination of Catalina seeds varied from 87 to 96% between 18 and 30 degrees C after 12 days. Germination of cochise seeds was optimum between 21 and 27 degrees C after 12 days. Germination of A-68 seeds was optimum at 27 degrees C and A-84 seeds at 30 degrees C. This study indicates that Catalina boer lovegrass and cochise lovegrass will germinate at relatively low temperatures. A-68 and A-84 lovegrasses, in contrast, require higher temperatures for optimum germination.
    • Forage Response of a Mesquite-Buffalograss Community Following Range Rehabilitation

      Bedunah, D. J.; Sosebee, R. E. (Society for Range Management, 1984-11-01)
      The influence of different range rehabilitation methods on honey mesquite control, herbage production, and grazing capacity were evaluated on a depleted clay loam range site in west Texas. Mesquite control by foliar application of 2,4,5-T + picloram, shredding, mechanical grubbing, mechanical grubbing and seeding to kleingrass, and mechanical grubbing and vibratilling increased herbage production and grazing capacity. Shredding increased soil cover by adding plant litter, but significantly controlled mesquite competition for only 2 years. Seeding to kleingrass resulted in a productive stand with a high estimated grazing capacity. Foliar spraying doubled grass production compared to no treatment and resulted in 76% mesquite mortality 3 years after treatment. Deferment from grazing was important in increasing herbage production during the study period; however, for maximum grazing capacity both mesquite control and proper grazing would be necessary.
    • Forage Preferences of Livestock in the Arid Lands of Northern Kenya

      Lusigi, W. J.; Nkurunziza, S.; Masheti, S. (Society for Range Management, 1984-11-01)
      The desirability of forage plants by livestock or wildlife is an important consideration in evaluating suitability of the range for grazing. This desirability may also in some cases be used in determining range condition. In many range types periodic determination of plant species composition provides the best indication of long-term trends. Evaluation of the effects of grazing on range flora usually requires that the vegetation be assigned to significant groups. This work represents the first attempt to make this kind of classification for the arid zone of northern Kenya in the study area of the UNESCO Integrated Project in Arid Lands (IPAL). It was required for the preparation of grazing plans for the largely nomadic pastoralists there. Preferences for 250 plant species have been assessed for camels, sheep, goats, and cattle. They are based on the best information presently available, and forms our basis for the classification of range condition for 147 range types in the study area.
    • Evaluating Soil Water Models on Western Rangelands

      Cooley, K. R.; Robertson, D. C. (Society for Range Management, 1984-11-01)
      The soil profile is an important water storage reservoir within the hydrologic cycle. An understanding of the factors affecting daily soil water status is necessary to increase or modify vegetation or water yields. Many mathematical simulation models have been developed to assess soil water status, but none were found that were specifically developed for use on Western rangelands. The purpose of this report was to test soil water models that appeared to be sufficiently general for adaption to rangeland conditions, to determine if they could provide adequate results, and the level of sophistication required. The 2 models selected for evaluation were the Ekalaka Rangeland Hydrology and Yield Model (ERHYM) developed for use during the growing season on grasslands of the northern Great Plains, and the Soil-Plant-Air-Water model (SPAW), which was developed for use with cultivated crops in the Midwest. Results indicated that both models could be adapted to produce adequate soil water information under rangeland conditions of southwestern Idaho. Overall, the somewhat simpler ERHYM model produced results more closely aligned to observed values than did SPAW. The lack of a snow accumulation and melt routine in SPAW (which could be added) appeared to be the main source of observed differences. These differences were a function of timing rather than a difference in total soil water at the end of each year, where results for the 2 models were very similar.
    • Estimating Seasonal Diet Quality of Pronghorn Antelope from Fecal Analysis

      Koerth, B. H.; Krysl, L. J.; Sowell, B. F.; Bryant, F. C. (Society for Range Management, 1984-11-01)
      Botanical composition of pronghorn antelope diets from fecal analysis and nutrient quality of samples of plants known to be used by pronghorn were evaluated from June 1979 to May 1980 in Oldham and Hartley counties of the Texas Panhandle. Pronghorn in this area consume forbs primarily throughout the year, followed by browse and grasses. Pronghorn exhibited an affinity for either Artemisia ludoviciana or Sphaeralcea coccinea, or both, in all seasons. Grass use was negligible. Seasonal crude protein estimates ranged from a low of 9.8% in winter to a high of 11.4% in spring. Estimates of phosphorus were lowest in winter (0.15%) and highest in spring (0.18%) corresponding to rapid plant growth. Digestible energy levels were lowest in the fall, approaching 2,227 kcal/kg, and highest in spring and summer, 2,656 and 2,631 kcal/kg, respectively. Average in vitro digestible organic matter coefficients for spring, summer, fall, and winter were 69%, 67%, 53%, and 61%, respectively. The combination of fecal analysis for botanical composition and nutrient content from samples of plants known to be ingested provides at least an estimate of nutrient content of the diet.
    • Establishment of Diffuse and Spotted Knapweed from Seed on Disturbed Ground in British Columbia, Canada

      Roze, L. D.; Frazer, B. D.; McLean, A. (Society for Range Management, 1984-11-01)
      The rangeland weeds diffuse and spotted knapweed (Centaurea diffusa L. and C. maculosa L.) were sown at densities of 208 to 1,504 seeds/m2 on disturbed rangeland in Westwold, British Columbia, in 25 × 25-cm plots. Both species established well to the rosettes stage at the lowest sowing densities, but only 5% of the diffuse knapweed rosettes bolted in the second year compared to 45% of the spotted knapweed rosettes. Intraspecific competition appeared to decrease the number of spotted knapweed rosettes bolting at the higher sowing densities.
    • Dietary Selection and Nutrition of Spanish Goats as Influenced by Brush Management

      Lopes, E. A.; Stuth, J. W. (Society for Range Management, 1984-11-01)
      Botanical composition of Spanish goat diets was only different when diets selected from tebuthiuron-treated pastures were compared to those from untreated and mechanically treated areas in the Texas Post Oak Savannah. However, all brush management treatments significantly affected the browse component in summer diets. Diets selected from untreated and mechanically treated pastures were dominated by browse, while grasses and grasslike plants occurred most in diets selected from the tebuthiuron-treated plots. Yet, during fall and winter, vines comprised the bulk of diets collected on these areas. Forbs were a minor dietary component. Goat diets from untreated and mechanically treated pastures consistently shifted from browse to grasses and grasslike plants as seasons advanced. Selection of grasses and grasslike plants on tebuthiuron-treated pastures declined sharply from summer through winter and increased through spring. Similar but inverse trends occurred in respect to vines and browse. Mean levels of crude protein (CP) in diets selected by esophageally fistulated goats grazing chemically treated pastures were significantly greater than in diets from the other pastures in winter and spring. In summer and fall, dietary forage material from all pastures contained equivalent levels of crude protein. Dietary in vitro digestible organic matter (IVDOM) was higher in summer and winter from tebuthiuron-treated pastures compared to mechanically treated and untreated areas. In fall, diets from tebuthiuron-treated pastures were higher in IVDOM content than those from untreated ones but were similar to diets from mechanically treated pastures. However, in spring all pastures receiving brush management yielded diets with higher IVDOM content than brush-treated areas. In general, methods of brush control had greater effects on IVDOM than on CP contents of diets.
    • Copper and Molybdenum Uptake by Forages Grown on Coal Mine Soils

      Neuman, D. R.; Munshower, F. F. (Society for Range Management, 1984-11-01)
      Coal mine soils have shown a tendency to produce leguminous vegetation containing elevated concentrations of molybdenum (Mo). The potential for cattle developing copper (Cu) deficiency by grazing vegetated areas is increased at one mine where a shale interburden material contains elevated Mo levels. The purpose of this study was to determine if mixing or dilution of the interburden with low-Mo sandy overburden would produce vegetation with undesirably high Mo levels or low Cu/Mo ratios. Concentrations of Cu, Mo, sulfur, and Cu/Mo ratios of several legumes and one grass species grown on these alkaline coal mine soils suggest that, with the exception of white sweetclover, mixing of the Mo-bearing interburden material with sandy overburden resulted in desirable elemental levels and ratios for grazing cattle if the mine soils were covered with an adequate depth (0.6 m) of suitable topsoil. Vegetation uptake of Mo was species and site specific.
    • Characteristics of Oak Mottes, Edwards Plateau, Texas

      Knight, R. W.; Blackburn, W. H.; Merrill, L. B. (Society for Range Management, 1984-11-01)
      Infiltration of live oak mottes on watershed properties was evaluated in July 1979 at the Sonora Agricultural Research Station. Infiltration rates of undisturbed live oak mottes and those with mulch layers removed were greater than rates of adjacent grass-dominated areas. However, infiltration rates of oak mottes with mulch layer and organic layer removed exposing the mineral were similar to those of adjacent grass-dominated areas. Infiltration rates of midgrass-dominated sites were greater than those of shortgrass-dominated sites. Greatest soil loss occurred from oak motte with mineral soil exposed with little differences between other treatments. Infiltration rates and sediment production of oak mottes were most influenced by grass standing crop, mulch and organic layers, soil organic matter, and water stable aggregates. Organic matter and water stable aggregates in the oak motte were similar and significantly greater than in the adjacent grass-dominated areas. Surface soil bulk density and texture were similar for the oak mottes and grass-dominated areas. Grass standing crop was similar for the oak motte and midgrass-dominated areas but significantly greater than for shortgrass-dominated areas. Mulch accumulation was 6 times greater in oak motte than midgrass areas and 43 times greater than in shortgrass areas.
    • Cattle Distribution on Mountain Rangeland in Northeastern Oregon

      Gillen, R. L.; Krueger, W. C.; Miller, R. F. (Society for Range Management, 1984-11-01)
      Cattle grazing distribution patterns were studied directly through observation and indirectly through plant utilization during 3 summer grazing seasons under continuous and deferred-rotation grazing systems. Small riparian meadows were the most preferred plant communities. Meadows covered 3-5% of the total observation area but 24-47% of all cattle were observed in those plant communities. Logged forest communities ranked second in animal preference when available. Relatively open Pinus ponderosa-Pseudotsuga menziesii plant communities were the most preferred forested habitats. Deferred grazing equalized cattle use between logged areas and P. ponderosa-P. menziesii forests and increased cattle use of riparian meadows. Heavily forested sites were least preferred by cattle. Slope gradient was the only physical factor consistently associated with cattle grazing distribution. Water distribution was not correlated with grazing patterns in uplant plant communities. Multiple regression models could not predict grazing distribution patterns with useful precision.