• Atrazine dissipation and off-plot movement in a Nebraska sandhills subirrigated meadow

      Brejda, J. J.; Shea, P. J.; Moser, L. E.; Waller, S. S. (Society for Range Management, 1988-09-01)
      Atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] can be used to modify species composition of naturally subirrigated Sandhills meadows. The potential for ground water contamination exists as the water table depth ranges from 0 to 3 m. Atrazine was applied at 2.2 and 3.4 kg ha-1 in May 1984, August 1984, or May 1985 to a Gannett fine sandy loam (Typic Haplaquoll, coarse-loamy, mixed, mesic) in a Nebraska Sandhills subirrigated meadow. Residues of atrazine applied in 1984 and 1985 carried over into 1985 and 1986, respectively. Herbicide dissipation and off-plot movement were monitored in 1985 by sampling soil at 0 to 5 cm and 5 to 15 cm depths within and outside the experimental areas. Atrazine dissipation initially approached zero-order kinetics after May 1985 application, but generally followed first-order kinetics during the entire 320-day sampling period. Atrazine half-life in the entire 0 to 15 cm sampling zone was 46 +/- 7 days. Herbicide concentrations at the 5 to 15 cm sampling depth did not exceed levels measured at 5 days after application. Low and highly variable atrazine concentrations detected in some of the untreated plots and in some off-plot soil samples indicated minimal lateral movement of the herbicide.
    • Atrazine impacts on shortgrass prairie microcosms

      Miller, M. S.; Doxtader, K. G. (Society for Range Management, 1995-07-01)
      Alterations in shortgrass ecosystem structure and function following long-term use of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3, 5-triazine,2,4-diamine] for increased secondary productivity raised concerns about sustainability of the practice. A microcosm approach was designed to 1) model the direction and temporal features of blue grama [Bouteloua gracilis H.B.K.) Lag. ex Steud.] biomass accumulation and tissue N, nitrate reductase activity, chlorophyll, total nonstructural carbohydrate, and phosphorus (P) levels following atrazine applications of 0.84 and 2.24 kg ha-1 and hydroxyatrazine (6-hydroxy-N-ethyl-N'-(1-methylethyl)-1,3, 5-triazine,2,4,-diamine) at 1.12 kg ha-1, and 2) to relate plant growth and metabolism changes to possible short- and long-term modifications of soil microbial abundance and activities associated with C and N transformations. Atrazine applied to dormant plant-soil microcosms reduced below-ground (crown plus root) biomass and shoot total nonstructural carbohydrate levels during regrowth. Atrazine application increased shoot chlorophyll content, N levels, and nitrate reductase activity, but not total plant N content. Decreased below-ground biomass accumulation, and increased shoot N and nitrate reductase activity levels were linked to decreased total nonstructural carbohydrate availability. Total plant P levels were highest at the intermediate atrazine rate. Differences in soil microbial biomass and activities, and chemical properties resulted primarily from presence of blue grama and duration of plant regrowth. Soil nitrifying activity was depressed in soil previously exposed to atrazine whether or not blue grama was present. Hydroxyatrazine was not identified as an important factor in observed plant or soil changes. Atrazine may alter shortgrass system structure and function by immediate impacts on primary producers and long-term impacts on soil microbial processes.
    • Atrazine Residue and Seedling Establishment in Furrows

      Eckert, R. E. (Society for Range Management, 1974-01-01)
      Deep furrows made with shovel openers and simulated disk-type furrows were evaluated for removal of atrazine residue from the seeded row and for seedling establishment in the atrazine-fallow technique of range seeding. Atrazine residue in all furrow treatments was below the toxic level for crested and intermediate wheatgrasses. Established stands of both species were similar in all furrow treatments. Therefore, the deep-furrow rangeland drill with disk openers appears suited for large-scale application of the atrazine-fallow technique.
    • Atrazine, Spring Burning, and Nitrogen for Improvement of Tallgrass Prairie

      Gillen, R. L.; Rollins, D.; Stritzke, J. F. (Society for Range Management, 1987-09-01)
      Spring application of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] (1.1 kg ha-1 a.i.), burning, and nitrogen (33 kg ha-1 as ammonium nitrate) were evaluated alone and in all combinations for improvement of mid-seral tallgrass prairie in northcentral Oklahoma. Studies were initiated in 1984 (Study I) and 1985 (Study II). Precipitation and successional status of the vegetation at treatment application were higher for Study II than for Study I. Atrazine effectively reduced forbs and annual grasses for 2 years after application. Atrazine stimulated warm-season perennial grasses but did not generally increase total herbage production. Burning was similar to atrazine for annual grass control in both studies. Burning was also similar to atrazine for forb control in Study I but had no impact on forb production in Study II. Burning increased perennial grass production only in the second year of Study I. Burning decreased total herbage production in the first year of Study I by reducing annual grasses and forbs but did not affect total herbage production on other dates. Nitrogen did not consistently increase perennial grass production but did increase forb production by 250-300% when applied alone. Both atrazine and burning rapidly shifted species composition in favor of desirable perennial grasses. Nitrogen was not as effective in changing species composition either alone or in combination with atrazine and burning. The number and complexity of treatment responses declined as successional status and/or precipitation improved.
    • Attentiveness of Guarding Dogs for Reducing Predation on Domestic Sheep

      Coppinger, R.; Lorenz, J.; Glendinning, J.; Pinardi, P. (Society for Range Management, 1983-05-01)
      Dogs used to protect domestic sheep from predators are expected to be attentive to the animals they guard. However, 40% of the sheep producers cooperating in our experimental program to assess the potential of Old World dogs to deter predation in the United States have expressed dissatisfaction with their dog's attentiveness. In contrast, European shepherds appear satisfied with their dogs. In order to find the causes of this apparent difference, a series of measured observations was made in Italy, and data on 4 different strains of imported guarding dogs working in the U.S. were analyzed. The results indicate that the 4 strains are significantly different in attentiveness, although overall it was remarkably similar to the actual attentiveness of Italian dogs. The attentiveness of livestock guarding dogs can be maximized for U.S. sheep producers by (1) selecting strains for superior attentive behavior and (2) adjusting management systems slightly to take advantage of the dogs' capabilities.
    • Attitudes About Range Research

      Society for Range Management, 2000-10-01
    • Austrailia at Ground Level

      Graves, Irene (Society for Range Management, 1985-12-01)
    • Australia's Foreign Assistance Programs Contributing to Rangeland Production

      Squires, V. R. (Society for Range Management, 1983-10-01)
    • Automated Animal Control: Can Discontinuous Monitoring and Aversive Stimulation Modify Cattle Grazing Behavior?

      Ruiz-Mirazo, Jabier; Bishop-Hurley, Greg J.; Swain, Dave L. (Society for Range Management, 2011-05-01)
      Grazing livestock freely select landscape resources, unless they are herded or constrained by fences. Automated animal control (AAC) systems offer an alternative to physical fences by using animal-positioning technology and aversive stimuli to deter animals from staying in sensitive environments and so limit their impact. This paper reports on a replicated field experiment completed to test whether occasional stimuli (audio cue followed by a mild electric stimulus), delivered by discontinuously activated AAC collars, could suffice to modify the grazing behavior of groups of cattle. Four groups of eight steers were confined in 8-ha rectangular paddocks that had an ad libitum supplement feeder located in one end to attract cattle. The steers’ positional information was recorded continuously for 3 d using a GPS receiver encased in a collar fitted around their neck. These data were used to characterize their use of the paddocks without intervention. Subsequently a restriction zone was activated on the collars. This zone contained the supplement feeders and represented approximately 10% of the paddock area. Cattle movement was again monitored during a second 3-d period, in which the steers were subjected to discontinuous aversive stimuli (5 min of stimulation followed by a random 0-30 min interval without stimulation) if they were located inside or moved into the restriction zone. Cattle visits to the restriction zone were shorter and the return interval longer when steers were subjected to discontinuous stimulation. Overall, there was a 97% reduction in the use of the restriction zone between the first and second deployments. These results suggest that grazing impact can be drastically reduced by making a zone less desirable through discontinuous aversive stimulation. Such a discontinuous (25% of the time on) AAC system can reduce power consumption in collars and so help overcome energy supply limitations that hinder commercial AAC applications.
    • Automated Rainout Shelter for Controlled Water Research

      Ries, R. E.; Zachmeier, L. G. (Society for Range Management, 1985-07-01)
      An automated rainout shelter was constructed at the Northern Great Plains Research Laboratory, Mandan, N. Dak., for use in conducting controlled water research to gain a better understanding of soil-plant-water relationships. The design and construction criteria were developed to accommodate many components that were commercially available. The primary components are: (1) foundation, (2) steel I-beam rail, (3) roller mechanism, (4) rainout shelter structure, (5) drive mechanism, (6) electrical control system, and (7) irrigation system. Wind, temperature, and precipitation sensors activate movement of the shelter to cover a plot area 11.5 × 30.3 m (38 × 100 ft), resulting in a modification of the selected environmental conditions. After inactivation of the sensors and a time delay, the rainout shelter automatically returns to its rest position, ready to repeat its cycle when the sensors are reactivated.
    • Autumn and spring drought periods affect vegetation on high elevation rangelands of Turkey

      Koç, A. (Society for Range Management, 2001-09-01)
      The amount and temporal distribution of precipitation received is of critical importance for regrowth and plant production on rangelands. The effects of drought in the autumn, and spring/summer, as they affected sheep fescue (Festuca ovina L.) dominated vegetation in Eastern Anatolia, Turkey, were examined between 1996 and 1998. Artificial drought was created using polyethylene rain-out shelters. The experiment was a randomized complete block design with 3 replications with a split-plot arrangement of treatments. Main plots included 2 autumn treatments: imposed artificial autumn-drought or a 40 mm of additional water plus rain. Sub-plots contained 4 treatments: artificial drought in May, June, July, or full spring rainfall. The number of reproductive shoots, aboveground biomass production, protein content, protein yield, canopy coverage and botanical composition were determined. Reproductive shoot numbers were reduced from 617 to 31 m(-2) when plants entered winter without autumn regrowth as a result of autumn-drought. Plots subjected to drought in the autumn had aboveground biomass of 424 kg ha(-1). Protein content of forage, crude protein yield and water use efficiency (WUE) were 11.6%, 49 kg ha(-1) and 1.5, respectively. These were compared with 1,038 kg ha(-1), 9.6%, 99 kg ha(-1), and 2.4, respectively, for plots received normal autumn precipitation in addition to 40 mm of additional water. Aboveground biomass production increased as short-term drought in spring was delayed but WUE was decreased. Autumn-drought had no effect on the proportion of grasses, but reduced legumes and resulted in an increase in other species. Spring/summer-drought had no effect on legumes but, as the onset of drought was delayed, grasses decreased and other species increased in composition. Autumn-drought reduced canopy coverage from 34.7% to 23.8% but spring drought had a negligible effect. Results indicated that autumn precipitation was crucial for productivity of these high elevation rangelands.
    • Autumn Mule Deer Foods on Heavily Grazed Cattle Ranges in Northwestern Colorado

      Lucich, G. C.; Hansen, R. M. (Society for Range Management, 1981-01-01)
      The botanical composition of the diets of domestic cattle and mule deer (Odocoileus hemionus) was estimated by microscopically examining fecal samples collected on deer winter ranges heavily used by cattle. Diet overlap ranged from 1 to 22% (x = 12%) on the nine areas studied. When cattle are forced from a grass dominated diet to browse forage on overgrazed ranges, diet overlap and therefore forage competition increases between deer and cattle.
    • Availability of foods of sage grouse chicks following prescribed fire in sagebrush-bitterbrush

      Pyle, W. H.; Crawford, J. A. (Society for Range Management, 1996-07-01)
      A study was conducted to determine the influence of prescribed fire on the availability of primary foods of sage grouse (Centrocercus urophasianus Bonaparte) chicks at Hart Mountain National Antelope Refuge, Lake County, Ore. from 1987 to 1989. Responses of certain primary foods and general food categories to fire were evaluated in sagebrush (Artemisia tridentata ssp. vaseyana Beetle)-bitterbrush (Purshia tridentata Pursh.) communities with a randomized block design established in stands where shrub cover exceeded 35%. Within blocks, habitat response was evaluated for 2 growing seasons on 4 pots used as controls, 3 plots burned in November 1987, and 4 plots burned in March 1988. Fall burning increased (P < 0.05) frequency of taxa in the dandelion tribe (Cichorieae). Other primary foods, including microsteris (Microsteris gracilis Hook.), desert-parsley (Lomatium spp. Raf.), and ground-dwelling beetles (Scarabaeidae, Tenebrionidae) were not influenced by burning. Spring and fall burning increased (P < 0.05) total forte cover and diversity, but decreased (P < 0.05) sagebrush cover. Prescribed fire may increase the supply of forbs available to sage grouse in montane sagebrush habitats used for brood-rearing where shrubs dominate stands at the expense of the herbaceous component.
    • Availability of Nitrogen and Other Nutrients on Four Fertilized Range Sites during the Active Growing Season

      Goetz, H. (Society for Range Management, 1975-07-01)
      The course of available soil nitrogen, phosphorus, potassium, and water were followed during the 1964-1969 growing seasons on four range sites in western North Dakota. Available nitrogen and potassium demonstrated regular high and low peaks of availability on three of the four sites studied. Available soil water does not appear to be the major factor in determinging the time and magnitude of the cyclic phenomena; rather differences in site characteristics play a greater role. Phosphorus showed little fluctuation throughout the growing season. The magnitude of the fluctuations between high and low points represents between 25 and 50% of the amount present with respect to nitrogen and potassium. The timing of the fluctuations is associated with major phenological events of the native vegetation on each site. Lag periods of about 15 days were observed between the 0-6 and 12-24 inch soil depths in nutrient availability. A consideration of the major periods and characteristics of activity and range site with respect to available soil nutrients is necessary to realize optimum production from native rangeland soils ecosystems.
    • Availability of Nitrogen, Phosphorous, and Sulfur After Brush Burning

      Vlamis, J.; Gowans, K. D. (Society for Range Management, 1961-01-01)
    • Available water influences field germination and recruitment of seeded grasses

      Abbott, L. B.; Roundy, B. A. (Society for Range Management, 2003-01-01)
      Periodic summer rainstorms in some semi-arid regions result in variable soil moisture and differential establishment of seeded species. A 2-year study investigated soil water effects on germination and survival of 6 native and 2 non-native southwestern U.S. grass species. Bags of seeds were buried and retrieved before and during the summer rainy season. High field germination in seed bags (20-100%) and limited germination in the laboratory of seeds that were ungerminated in seedbags (0-45%) were exhibited by 6 native grasses following initial rainfall events in which the surface soil was saturated for 2 days or water potential (1-3 cm depth) was above -1.5 MPa for more than 9 days. Fewer Lehmann lovegrass (Eragrostis lehmanniana Nees) seeds germinated in response to initial and subsequent rainfall events (0-49%), but this species retained more residual germinable seeds (49-99%) than all other species studied. For 2 sowing dates, the soil drying front exceeded estimated seminal root depth 13 days after germination. Lack of recruitment for some species sown on these dates was probably due to seedling desiccation before adventitious roots had sufficient time to develop. The ability of Lehmann lovegrass to retain a viable seedbank when rainstorms are separated by long dry periods allows it to establish better than some native grasses that germinate quickly and are then subject to seedling desiccation. During a summer with more consistent rainfall, native species recruitment was greatest when seeds were planted during, rather than before the summer rainy season.
    • Avian community response to fire and mechanical shrub control in south Florida

      Fitzgerald, S. M.; Tanner, G. W. (Society for Range Management, 1992-07-01)
      Effects of prescribed fire and roller chopping applied in 2 seasons on woody vegetation and the associated avian community of a southwestern Florida former dry prairie were studied. There were 5 vegetation treatments with 2 replications of each; treatments were control, winter burn, winter chop, summer burn, and summer chop. Percent shrub cover was sampled with line intercept transects. Birds were censused 25 times using the variable circular plot method. Burning in either season reduced shrub cover temporarily; chopping in either season reduced shrub cover significantly and it remained reduced throughout the 15 months of this study. Bird species richness and abundance were similar in control and burn plots. Birds were not seen in summer chop plots up to 5 months posttreatment. Bird species richness and abundance remained low in both winter and summer chop plots. Bird species that were observed in chop plots were mostly open country, grassland inhabitants, indicating a trend toward prairie restoration.
    • Avian Community Response to Grazing Intensity on Monoculture and Mixed Florida Pastures

      Wilcox, Emma V.; Tanner, George W.; Giuliano, William M.; McSorley, Robert (Society for Range Management, 2010-03-01)
      Monoculture and mixed pastures in Florida provide habitat for a variety of resident and migratory bird species. The objectives of this study were to investigate the effects of grazing on vegetation structure and bird species richness and abundance in grazed monoculture and mixed pastures. Study pasture units were subject to four cattle grazing intensities: 0 = nongrazed (control), 15 = low, 20 = medium, or 35 = high animal units (AU) per pasture unit (no cattle, 1.3, 1.0, and 0.6 ha AU-1, on monoculture pastures and no cattle, 2.1, 1.6, and 0.9 ha AU-1, on mixed pastures). Monoculture pastures displayed a greater decrease in spatial heterogeneity of the vegetative community in the presence of grazing than mixed pastures. An increase in grazing intensity led to declines in total avian species richness and abundance and species richness within short-distance migrant, neotropical migrant, and permanent resident guilds on monoculture pastures. Declines in total species richness and abundance and neotropical migrant guild species richness and abundance were observed on mixed pastures subject to increasing grazing intensity. However, species richness within short-distance migrant and urban guilds and abundance within the grassland guild increased on this pasture type in the presence of grazing. Loss of spatial heterogeneity typically results in a lack of suitable habitat for birds that occupy the extremes of the vegetation structure gradient. This can lead to a loss of species richness and abundance. For the majority of avian guilds, a low grazing intensity of 1.3 ha AU-1 and 2.1 ha AU-1 on monoculture and mixed pasture, respectively, is recommended to maintain abundance. However, these grazing intensities may result in declines in species richness. Ultimately, if a range of avian species are to be supported on monoculture and mixed pastures, spatial heterogeneity of plant structure and composition must be maintained. 
    • Avian habitat following grazing native warm-season forages in the mid-south United States

      Harper, C. A.; Birckhead, J. L.; Keyser, P. D.; Waller, J. C.; Backus, M. M.; Bates, G. E.; Holcomb, E. D.; Brooke, J. M. (Society for Range Management, 2015-03)
      Native warm-season grasses (NWSG) currently are being promoted for livestock forage and biofuels feedstock in the Mid-South. However, there are no published data on how NWSG managed with livestock in the Mid-South may affect habitat for wildlife. We conducted a study to evaluate habitat for grassland songbirds and northern bobwhite (Colinus virginianus) in response to two cattle grazing treatments in NWSG pastures across three sites in Tennessee, 2010 and 2011. We evaluated vegetation composition and structure along with invertebrate availability during the primary nesting season for grassland songbirds and the typical brood-rearing season for the northern bobwhite. Grazing treatments included full-season (May to August) grazing and early-season (30 days beginning in May) grazing, after which subsequent growth was taken as a biofuel harvest postdormancy. Forage treatments included big bluestem/indiangrass mixture, switchgrass, and eastern gamagrass. Vegetation composition was dominated by the planted forages in all pastures. All forage types and both grazing treatments provided suitable structure for grassland songbirds and bobwhite during the primary nesting season. Full-season grazing maintained suitable structure through the brooding period, with greater openness at the ground level and angle of obstruction, as well as optimal vegetation height (<60 cm). Structure within early-season grazing treatments became dense after cattle were removed with less openness at ground level than what brooding bobwhites typically use. Invertebrate biomass was sufficient in all forage types and grazing treatments to support bobwhite broods. We recommend livestock producers in the Mid-South use full-season grazing that maintains grass height of approximately 40 cm in production stands of NWSG to maximize benefits for grassland birds and northern bobwhite. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Award-Winning Range Management in Montana

      Taylor, Vern; Hoff, Chris; Brooks, Sandy (Society for Range Management, 1992-08-01)