• Vegetation Changes between 1943 and 1965 on the Shortgrass Plains of Wyoming

      Lang, R. (Society for Range Management, 1973-11-01)
      Ground cover estimates on permanently marked plots in East Central Wyoming were compared between 1943 and 1965. On grazed native range plots, shortgrasses increased and midgrasses decreased when comparing 1965 to 1943. Plots in exclosures showed a decrease in shortgrass cover and an increase in cover of midgrasses. Generally, big sagebrush (Artemisia tridentata) and plains pricklypear (Opuntia polyacantha) increased markedly on both open and exclosure plots. Due to excessive grazing pressure, the total perennial grass cover on a section of abandoned farmland was nearly 35% less in 1965 than in 1943.
    • Water Harvesting Efficiencies of Four Soil Surface Treatments

      Rauzi, L.; Fairbourn, M. L.; Landers, L. (Society for Range Management, 1973-11-01)
      Water harvesting efficiency of four soil surface treatments was studied for 5 years at Gillette, Wyoming, and the Central Plains Experimental Range near Nunn, Colorado. The surface treatments consisted of rangeland, salt (NaCl), plastic covered with pea gravel, and asphalt roll roofing. Average water harvesting efficiencies ranged from 5% on rangeland at Gillette to 105% from the asphalt roll roofing treatment at the Central Plains Experimental Range. Spring and fall snowstorms resulted in water harvesting efficiencies of over 100% at the Central Plains Experimental Range. Precipitation was highest in April, May, and June and lowest in August.
    • Wax-treated Soils for Harvesting Water

      Fink, D. H.; Cooley, G. W. (Society for Range Management, 1973-11-01)
      Shortage of water for livestock often limits the carrying capacity of rangeland. Water harvesting can provide extra water. Paraffin wax was applied as granules or flakes on the surface of two experimental watershed plots and allowed to melt and spread in the hot desert sun to form a hydrophobic soil surface, which then readily shed water. The wax-treated plots yielded an average of 90% precipitation runoff, compared to only 30% runoff from two untreated plots and to 100% runoff from a butyl-covered plot.
    • Effects of Climate on Forage Yields and Tree-ring Widths in British Columbia

      McLean, A.; Smith, J. H. G. (Society for Range Management, 1973-11-01)
      On forested lands (1954 to 1969) 109 annual forage yields from 12 locations were studied. Very dry springs and unusually low annual precipitation resulted in low forage yields. Dry summer months were associated with superior yields provided the past year had been wet. The relationship was not consistent, however, nor was there a consistent relationship between tree-diameter growth and climate based on monthly or seasonal temperature or precipitation records. Annual forage yields were least on the Dewdrop and highest on the East Mara ranges, 325 and 1017 lb oven dry, respectively. Forage yields on open rangelands (1954 to 1969), although only moderately associated with individual values for seasonal average temperature or total precipitation, could be estimated very well by all weather variables describing a 15-month period. The 190 observations of yield from 16 open rangeland locations averaged 544 lb oven dry, with a minimum of 84 lb in 1967 and a maximum of 616 lb in 1965. Expressed as percentages of 1963 yields, annual forage weights averaged 116% and ranged from 53 to 214%. Such large variations as a result of fluctuations in climate are of obvious importance to graziers, and the possibility that forage yields can be related to long-term variations in tree growth merits further study.
    • 14 Years of Rabbitbrush Control in Central Oregon

      Mohan, J. M. (Society for Range Management, 1973-11-01)
      Fourteen years (1956 to 1970) of chemical control for rubber and green rabbitbrush using the ester forms of 2,4-D produced consistent control, ranging from 85 to 98% on rubber rabbitbrush. The amount of new twig growth, soil moisture, rate and methods of application, total seasonal twig growth, and subsequent drought conditions proved critical for effective kills. Selective kills were achieved by manipulation of these factors. Site potential and response to changes that result from chemical control must be recognized. "Drainage Effect" is a complex of thermal drafts, topography, and soil differences that can adversely influence the percentage of rabbitbrush control achieved.
    • How to Prepare a Range Soil Monolith

      Donaldson, Norman C.; Beck, Dewayne J. (Society for Range Management, 1973-11-01)
      Step-by-step instructions are given for preparation of range soil and vegetation monoliths. These are slices of range vegetation and soil mounted on boards for demonstrations and educational purposes. A complete list of materials needed for preparation of monoliths is described.
    • Floating Sheets of Foam Rubber for Reducing Stock Tank Evaporation

      Dedrick, A. R.; Hansen, W. R.; Williamson, W. R. (Society for Range Management, 1973-11-01)
      Foam rubber sheet stock, 48 inches wide and 3/16 inch thick, was lap jointed, using a contact cement, to fabricate three floating covers. Their performance was evaluated on 24-and 30-foot diameter water-storage tanks. Generally, field performance was satisfactory. Minor problems observed included: pecking by birds, temporary clogging of bailing holes, and separation of the cover from an ice surface. None of these problems are expected to cause cover failure. The estimated cost of saving potentially evaporated water in a 4-foot per year evaporation zone ranges from $1.80 to $2.00 per 1,000 gallons. Such a cost may be justifiable when compared to costs of alternate means of producing or saving an equal amount of water.
    • Differential Tolerance of Some Arid-Range Wheatgrasses to Snow Mold

      Bleak, A. T.; Keller, W. (Society for Range Management, 1973-11-01)
      Snow mold is most severe under a prolonged spring snow cover, where temperatures are favorable for growth of certain fungi. In the spring of 1971 a replicated plot containing 30 accessions of wheatgrasses provided an opportunity to study differential tolerance to snow mold. On the basis of the percent of 1-year-old plants killed, fairway wheatgrass A-12477X (mean of 4 accessions) was most susceptible with 29.4% mortality, fairway wheatgrass A-1770 (3 accessions) averaged 13.7%, and fairway wheatgrass NM-251 (5 accessions) averaged 2.7%. Crested wheatgrass Nordan (4 accessions) averaged 4.9% mortality. Crested wheatgrass A-1874 (1 accession) averaged 11.3% and crested wheatgrass PI 277354 (2 accessions) averaged 2.3%. Five other sources of crested wheatgrass had significantly less mortality than Nordan. Siberian wheatgrass (5 accessions) averaged 4.2% mortality. Intermediate wheatgrass (1 accession) had no mortality, and only 2 plants out of 300 showed moderate injury.
    • Downy Brome-Intruder in the Plant Succession of Big Sagebrush Communities in the Great Basin

      Young, J. A.; Evans, R. A. (Society for Range Management, 1973-11-01)
      We investigated succession on six big sagebrush sites of different potential ranging from the edge of the salt desert shrub to seral communities in the pinon/juniper woodland where the brush overstory had been removed by hand cutting. Depending upon the site, herbaceous communities that developed after elimination of overstory cover were composed of either a diversity or a relatively limited number of species of native annual forbs. Alien annual forbs were initial dominants on sites where seed source of these species was available. Dominance by downy brome caused a marked reduction of native annual species. Downy brome was seeded for 3 consecutive years in each of six different big sagebrush communities. On the majority of the sites, providing a seed source resulted in establishment and near total dominance by downy brome. The established populations have persisted and continued to dominate the communities. Some sites were outside the seedbed potential of downy brome, and seeding resulted in establishment only once in 3 years. Presence of plant litter and a rough microtopography were key seedbed characteristics permitting downy brome establishment on these sites.
    • Deferred-rotation Grazing with Steers in the Kansas Flint Hills

      Owensby, C. E.; Smith, K. L.; Anderson, K. L. (Society for Range Management, 1973-11-01)
      Deferred-rotation grazing of Kansas Flint Hills' range grazed by steers May 1 to October 1 was compared to season-long stocking from 1950 through 1966. Deferred-rotation pastures had higher forage production and range condition than season-long stocked pastures. Steer gains were higher on season-long than deferred-rotation pastures. Increased stocking rates were more feasible on deferred-rotation pastures than on season-long pastures.
    • Effect of Clipping on Survival of Crested Wheatgrass Seedlings

      McGinnies, W. J. (Society for Range Management, 1973-11-01)
      Seedlings of crested wheatgrass (Agropyron desertorum (Fisch. ex Link) Schult.) from spring plantings were clipped to a 1.3-cm stubble or to ground level in the year of seeding in 6 years between 1954 and 1970. Two to nine clipping dates per year, between May and August, were used. Seedling survival was measured in the fall of the year of seeding. Clipping to 1.3 cm reduced survival by 0 to 13%, but the reductions were considered to be of no practical consequence. Clipping to ground level reduced survival by 0 to 61%, and the reduction varied greatly between years, dates of clipping, and dates of clipping within years. There was no consistent relationship between date of clipping and survival. It was not possible to predict seedling mortality from date of clipping, or from number of tillers or height of seedlings at time of clipping. In 1970, when height measurements were made, plant height in September decreased for later dates of planting, and height of regrowth after clipping decreased with later dates of planting and later dates of clipping.
    • Mortality in Crested Wheatgrass and Russian Wildrye

      McLean, A.; van Ryswyk, A. L. (Society for Range Management, 1973-11-01)
      Mortality in crested wheatgrass and Russian wildrye near Kamloops, B.C., was observed in spring, 1970, and appeared to result from lower than average soil moisture reserves the previous season. Damage was heavy on a silt loam that graded to loamy fine sand at 50-cm depth but was negligible on a uniform sandy loam overlying cobbly loamy sand. Field moisture levels below 25-cm depth in the soil were greater on the sandy loam site than on the silt loam in spring, 1970. In that year, crested wheatgrass reached seed-set stage on the former, but inflorescences did not emerge from the boot on the latter site, where significant mortality occurred. No other published account of severe mortality of established stands of these grasses has been found.
    • Model Development for a Deferred-grazing System

      Smith, R. C. G.; Williams, W. A. (Society for Range Management, 1973-11-01)
      A model of the early growth of an annual pasture and liveweight response of grazing sheep was built using first order differential equations to study the practice of deferred grazing. The dynamic behavior of the system over time was simulated by solving the equations on a computer. The model is an interpretative representation of a subterranean clover pasture in Western Australia and relates to a specific site and set of seasonal conditions. Use was made of the literature and a recent grazing experiment to develop the model. Herbage growth is estimated from known relationships with radiation received, leaf area exposed, soil moisture, and herbage removed by grazing. Change in soil moisture is estimated from rainfall and pan evaporation data. Defoliation is based on stocking rate, pasture weight, and pasture height to account for the effects of animal numbers and availability of pasture. Liveweight change of the consuming animal is calculated as a function of intake, digestibility, and the partitioning of metabolizable energy between maintenance and weight change. Validation of the model by results observed in the grazing experiment is presented.
    • Runoff and Sediment Yields from Runoff Plots on Chained Pinyon-Juniper Sites in Utah

      Gifford, G. F. (Society for Range Management, 1973-11-01)
      Runoff and sediment production from a chained pinyon-juniper site in both southeastern and southwestern Utah was measured from about June 6 to October 1 over a 5-year period (1968-1972) using .04-hectare (0.11 acre) runoff plots. Treatments evaluated included chained-with-debris-windrowed, chained-with-debris-in-place, and natural woodland. All treatments were fenced to exclude livestock. Runoff events occurred at both sites during only 2 years (1968, 1970) of the study. Results indicate that chained-with-windrowing plots yield from 1.2 to 5 times more water during a runoff event than respective woodland plots. Runoff from debris-in-place plots was equal to or less than that measured from the natural woodland for all storms. Runoff data and sediment indexes indicate that when runoff exceeds about 0.1 cm from the woodland, from 1.6 to 6 times more sediment can be expected from windrowed sites than from adjacent woodland. Sediment yields from debris-in-place sites were similar to those from adjacent unchained woodland for all storms during this study.
    • Satellite Imagery for Assessing Range Fire Damage in the Nebraska Sandhills

      Seevers, Paul M.; Jensen, Peter N.; Drew, James V. (Society for Range Management, 1973-11-01)
      Initial imagery from the first Earth Resources Technology Satellite indicates that satellite-acquired data is of value in determining the location and extent of range fire in the Sand Hills region of Nebraska. Preliminary results suggest that it can also provide a tool for monitoring soil erosion by wind and evaluating the recovery of vegetation in burned areas.
    • Seasonal Change in Nutritive Value of Bluestem Pasture

      Rao, M. R.; Harbers, E. F.; Smith, E. F. (Society for Range Management, 1973-11-01)
      Esophageally fistulated steers were used to determine organic matter intake and digestibility of bluestem pastures during the summer grazing season. Following a 48-hour total fecal collection period, esophageally fistulated steers were used to collect grazed samples of native pastures during June, July, August, September, and October. Esophageal samples were higher in ash and crude protein and lower in crude fiber, N-free extract, and acid detergent fiber than were hand-clipped samples. In vitro dry and organic matter digestibilities were higher in forage collected by cattle than in hand-clipped forage. Multiple regression equations were developed to predict in vitro digestibility. Only crude protein and acid-detergent fiber were highly correlated with digestibility. Average daily intakes of organic matter, digestible crude protein, and digestible energy by steers on pasture were estimated from fecal nitrogen regression established from hay trials. Protein apparently became limiting about mid-July and energy in late August. The positive effects of burning were increased forage yield and weight gain with lowered lignin content.
    • Soil Physical and Physico-chemical Variability Induced by Atriplex nummularia

      Sharma, M. L. (Society for Range Management, 1973-11-01)
      Spatial variability in two soils supporting 10-year old stands of saltbush (Atriplex nummularia) was examined by evaluating various soil physical and physico-chemical properties under and between the plants. The differences in soil properties between these two positions were mostly significant for the surface layer (0-7.5 cm) but only in a few cases for the 7.5-15 cm layer. No differences were observed below this depth. Presence of A. nummularia resulted in increased electrolyte concentration, higher sodium adsorption ratio, and higher levels of exchangeable sodium and organic matter in the surface soil. Standard laboratory measurements showed that these physico-chemical changes induced a significant deterioration in the structure of the surface soil under the plants as indicated by reduced aggregate stability, poorer drainage, and lowered hydraulic conductivity. Field studies suggested that the bulk density of the surface soil was reduced under the plants but that water penetration and storage in the profile after rains remained unaffected. Probable reasons for these effects are discussed.
    • Soil Moisture Response to Spraying Big Sagebrush the Year of Treatment

      Sturges, D. L. (Society for Range Management, 1973-11-01)
      Spraying big sagebrush with 2,4-D in Wyoming reduced soil moisture loss 24% between June 24, the treatment date, and September 30. All of the reduction accrued by August 4, during the time of active vegetative growth. Moisture was measured to a 6-ft depth and 83% of the reduction was located in soil 2 to 6 ft deep.
    • Southern Pine Overstories Influence Herbage Quality

      Wolters, G. L. (Society for Range Management, 1973-11-01)
      A cover of young longleaf or slash pines increased protein and phosphorus and decreased nitrogen-free extract in herbage on pine-bluestem range. Under protection from grazing, the proportion of big bluestem in the herbage stand increased more on forested than cutover land. Herbage decreased about 15 lb/acre for every 1 ft2 increase in pine basal area.