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Sample records for grazing whiteclover red

  1. Habitat relationships of eastern red-backed salamanders (Plethodon cinereus) in Appalachian agroforestry and grazing systems

    Treesearch

    Breanna L. Riedel; Kevin R. Russell; W. Mark Ford; Katherine P. O' Neill; Harry W. Godwin

    2008-01-01

    Woodland salamander responses to either traditional grazing or silvopasture systems are virtually unknown. An information-theoretic modelling approach was used to evaluate responses of red-backed salamanders (Plethodon cinereus) to silvopasture and meadow conversions in southern West Virginia. Searches of area-constrained plots and artificial...

  2. Potential Activity, Size, and Structure of Sulfate-Reducing Microbial Communities in an Exposed, Grazed and a Sheltered, Non-Grazed Mangrove Stand at the Red Sea Coast

    PubMed Central

    Balk, Melike; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    After oxygen, sulfate is the most important oxidant for the oxidation of organic matter in mangrove forest soils. As sulfate reducers are poor competitors for common electron donors, their relative success depends mostly on the surplus of carbon that is left by aerobic organisms due to oxygen depletion. We therefore hypothesized that sulfate-cycling in mangrove soils is influenced by the size of net primary production, and hence negatively affected by mangrove degradation and exploitation, as well as by carbon-exporting waves. To test this, we compared quantitative and qualitative traits of sulfate-reducing communities in two Saudi-Arabian mangrove stands near Jeddah, where co-occurring differences in camel-grazing pressure and tidal exposure led to a markedly different stand height and hence primary production. Potential sulfate reduction rates measured in anoxic flow-through reactors in the absence and presence of additional carbon sources were significantly higher in the samples from the non-grazed site. Near the surface (0–2 cm depth), numbers of dsrB gene copies and culturable cells also tended to be higher in the non-grazed sites, while these differences were not detected in the sub-surface (4–6 cm depth). It was concluded that sulfate-reducing microbes at the surface were indeed repressed at the low-productive site as could be expected from our hypothesis. At both sites, sulfate reduction rates as well as numbers of the dsrB gene copies and viable cells increased with depth suggesting repression of sulfate reduction near the surface in both irrespective of production level. Additionally, sequence analysis of DNA bands obtained from DGGE gels based on the dsrB gene, showed a clear difference in dominance of sulfate-reducing genera belonging to the Deltaproteobacteria and the Firmicutes between sampling sites and depths. PMID:26733999

  3. Grazing Occultations.

    ERIC Educational Resources Information Center

    Cunningham, Doug; Hlynialuk, John

    1983-01-01

    A "grazing occultation" occurs when a star or other astronomical body is covered up by the extreme northern or southern limb of the moon in its easterly motion about the earth. Graze phenomena, organizing a graze expedition, and the scientific/educational value of observing grazes are among the topics discussed. (JN)

  4. Direct and indirect effects of high pCO2 on algal grazing by coral reef herbivores from the Gulf of Aqaba (Red Sea)

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Steinke, M.; Fine, M.

    2013-12-01

    Grazing on marine macroalgae is a key structuring process for coral reef communities. However, ocean acidification from rising atmospheric CO2 concentrations is predicted to adversely affect many marine animals, while seaweed communities may benefit and prosper. We tested how exposure to different pCO2 (400, 1,800 and 4,000 μatm) may affect grazing on the green alga Ulva lactuca by herbivorous fish and sea urchins from the coral reefs in the northern Gulf of Aqaba (Red Sea), either directly, by changing herbivore behaviour, or indirectly via changes in algal palatability. We also determined the effects of pCO2 on algal tissue concentrations of protein and the grazing-deterrent secondary metabolite dimethylsulfoniopropionate (DMSP). Grazing preferences and overall consumption were tested in a series of multiple-choice feeding experiments in the laboratory and in situ following exposure for 14 d (algae) and 28 d (herbivores). 4,000 μatm had a significant effect on the biochemical composition and palatability of U. lactuca. No effects were observed at 1,800 relative to 400 μatm (control). Exposure of U. lactuca to 4,000 μatm resulted in a significant decrease in protein and increase in DMSP concentration. This coincided with a reduced preference for these algae by the sea urchin Tripneustes gratilla and different herbivorous fish species in situ (Acanthuridae, Siganidae and Pomacanthidae). No feeding preferences were observed for the rabbitfish Siganus rivulatus under laboratory conditions. Exposure to elevated pCO2 had no direct effect on the overall algal consumption by T. gratilla and S. rivulatus. Our results show that CO2 has the potential to alter algal palatability to different herbivores which could have important implications for algal abundance and coral community structure. The fact that pCO2 effects were observed only at a pCO2 of 4,000 μatm, however, indicates that algal-grazer interactions may be resistant to predicted pCO2 concentrations in the

  5. Ecology of the red-tide dinoflagellate Ceratium furca: distribution, mixotrophy, and grazing impact on ciliate populations of Chesapeake Bay.

    PubMed

    Smalley, Gabriela W; Coats, D Wayne

    2002-01-01

    Ceratium furca is a primarily photosynthetic dinoflagellate also capable of ingesting other protists. During 1995 and 1996, we documented the abundance of C. furca in Chesapeake Bay and determined grazing rates on prey labeled with fluorescent microspheres. Abundance usually remained below 20 cells ml(-1), although the species was capable of localized late-summer blooms (< or = 478 cells ml(-1)) in the more saline lower to mid-Bay region. Feeding rates ranged from 0 to 0.11 prey dinoflagellate(-1) h(-1) or from 0 to 37 pg C dinoflagellate(-1) h(-1) and were highest at lower salinities. Clearance rates averaged 2.5 +/- 0.35 microl dinoflagellate(-1) h(-1). Impact of C. furca feeding on prey populations was higher in the lower Bay, averaging 67% of Strobilidium spp. removed d(-1). Ingestion rates were positively correlated with prey abundance and dissolved inorganic nitrogen, but negatively with salinity, depth, dissolved inorganic phosphorus, and inorganic P:N ratio. Daily consumption of prey biomass by C. furca averaged 4.6% of body carbon, 6.5% of body nitrogen, and 4.0% of body phosphorus. with maximal values of 36, 51, and 32%, respectively. Thus, the ability to exploit an organic nutrient source when inorganic nutrients are limiting may give C. furca a competitive advantage over purely photosynthetic species.

  6. Egg production, egg quality and crop content of Rhode Island Red hens grazing on natural tropical vegetation.

    PubMed

    Mohammed, Khaled Abouelezz Fouad; Sarmiento-Franco, Luis; Santos-Ricalde, Ronald; Solorio-Sanchez, Javier Francisco

    2013-02-01

    The aim of this experiment was to study the suitability of the outdoor system for Rhode Island Red hens under the tropical conditions of southern Mexico. Twelve floor pens, each containing four birds, were divided randomly into two groups. The first group was raised indoors only, while each of the second group replicates had access to an outdoor area with natural-grown vegetation from 0800 to 1700 hours daily. Both groups fed ad libitum on a commercial layers diet. The results revealed no differences in body weight between treatments. The outdoor group recorded significantly higher egg laying rate (86.90 vs. 78.05 %), higher egg mass (50.66 vs. 45.30 g egg/hen/day), and higher feed intake (103.70 vs. 97.67 g/day) versus the indoor group. The outdoor group had eggs with darker yellow yolks (9.46 vs. 5.46), lower yolk, and higher albumen proportions (P < 0.05) versus the indoor group. The crop content of the outdoor hens consisted of 86.55 % concentrated feed, 6.30 % plant material, 2.27 % grit stones, 1.69 % snails and oyster shells, 1.25 % seeds, 0.95 % farm wastes, and 0.99 % insects, worms, and larvae. Of the outdoor hens, 43.1 % was observed to be in the range at each scanning time. The outdoor system in the tropics had beneficial effects on Rhode Island Red hen performance, and the hens utilized the outdoor area effectively and obtained various feed items.

  7. Amazing Grazing.

    ERIC Educational Resources Information Center

    Peterson, Cris

    Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

  8. Amazing Grazing.

    ERIC Educational Resources Information Center

    Peterson, Cris

    Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

  9. [The supply of wild ruminants with major and trace elements. 1. The cadmium content of winter grazing and the cadmium status of red deer, fallow deer, roes and moulons].

    PubMed

    Anke, M; Grün, M; Briedermann, L; Missbach, K; Hennig, A; Kronemann, H

    1979-12-01

    The Cd-determination of 10 different winter grazings for wild ruminants in seven different biotopes showed significant differences of the habitats resulting from the previous Cd-emission of metallurgy smelting non-ferrous metals. The winter grazing of the Tharandt Forest and the Harz mountains contained significantly more Cd than that of the Lower Flaming hills, the western Erzgebirge and the northern agrarian areas. The bark and the tips of conifer twigs, twigs of oak and mountain ash, bilberry and heather plants, i. e. perennial plants resp. parts of plants proved to be particularly rich in Cd. On an average, wild ruminants consume more Cd than domesticated ruminants, which do not consume parts of perennial plants. The rumen contents of all wild ruminants contained, with 0.20 to 0.25 mg/kg dry matter more Cd than could be expected from the content of the grazing. In the Cd-contaminated areas the amount of Cd in the rumen contents too showed the Cd-load. The kidneys, livers and the covering hair of a total of 172 head red deer, roes and mouflons reflected the Cd-load and the dependence of the Cd-level on the age. The Cd-concentration ascertained in the organs of the wild ruminants was compared with that of sheep and cattle. The, on an average, higher Cd-load of the wild ruminants was confirmed. The kidneys of wild ruminants older than five years should, as a general principle, not be eaten and neither should the livers of animals from Cd-contaminated biotopes. The limb defects of mouflons from Cd-contaminated areas are discussed in connection with Cd-induced secondary Cu-deficiency resp. Mn- and Zn-deficiency. A reference is made to further works.

  10. Biochanin A, an isoflavone produced by red clover, promotes weight gain of steers grazed in mixed grass pastures and fed dried-distillers' grains

    USDA-ARS?s Scientific Manuscript database

    Biochanin A (BCA) is an isoflavone produced by red clover (Trifloium pratense L.) that can inhibit hyper-ammonia producing bacteria (HAB) to reduce deamination in the rumen and increase the feed amino acids available for gastric digestion. An in vitro experiment was conducted to evaluate the effect...

  11. Effect of alternate and simultaneous grazing on endoparasite infection in sheep and cattle.

    PubMed

    Brito, Daiana Lima; Dallago, Bruno Stéfano Lima; Louvandini, Helder; dos Santos, Viviane Rodrigues Verdolin; Torres, Sonia Emília Figueirêdo de Araújo; Gomes, Edgard Franco; do Amarante, Alessandro Francisco Talamini; de Melo, Cristiano Barros; McManus, Concepta Margaret

    2013-01-01

    This experiment was carried out on 8 ha of Panicum maximum cv. Tanzania pastures, with rotational grazing consisting of 7 days of occupation and 21 days of rest. Four treatments were evaluated: cattle grazing alone (BOV), sheep grazing alone (OVI), cattle and sheep grazing simultaneously (SIM) and cattle grazing followed by sheep (alternate - ALT). Twenty heifers and 30 male Santa Inês lambs were used. Fecal egg count (FEC) and fecal cultures were carried out. Blood was also collected to examine red and white cell series, total plasma protein (TPP), albumin and hemoglobin. FEC and estimated nematode pathogenicity index in sheep were lower in the SIM treatment. The Haemonchus spp. proportion was higher in isolated grazing systems. For sheep, mixed grazing was shown to reduce endoparasite infection, and SIM was better than ALT. For cattle, no difference between grazing systems was seen. Therefore, simultaneous grazing (sheep and cattle) may be a tool for reducing the need for anthelmintic treatments in sheep.

  12. Streambank response to simulated grazing

    Treesearch

    Warren P. Clary; John W. Kinney

    2000-01-01

    Simulated grazing techniques were used to investigate livestock impacts on structural characteristics of streambanks. The treatments consisted of no grazing, moderate early summer grazing, moderate mid summer grazing, and heavy season-long grazing. The heavy season-long treatment resulted in a 11.5 cm depression of the streambank surface, while the moderate treatments...

  13. Prescribed grazing on pasturelands

    USDA-ARS?s Scientific Manuscript database

    Principles of grazing management center round the temporal and spatial distribution of various kinds and number of livestock. Within the context of this chapter, management of grazing or browsing will be characterized in terms of intensity, method, and season (timing), and as a function of the type ...

  14. MONITORING GRAZING LANDS

    USDA-ARS?s Scientific Manuscript database

    An important step in developing a ranch or allotment management plan for grazing lands is defining a rangeland monitoring program to evaluate progress toward achieving management objectives. A monitoring program can: 1) help determine the benefits gained from changes in grazing management or invest...

  15. An international terminology for grazing lands and grazing animals

    USDA-ARS?s Scientific Manuscript database

    In 1991, Terminology for Grazing Lands and Grazing Animals was published with the objective of ‘developing a consensus of clear definitions of terms used in the grazing of animals.’ During the XVIII International Grassland Congress, held in Canada in 1997, a new Terminology working group was formed ...

  16. Advances in grazing distribution practices

    USDA-ARS?s Scientific Manuscript database

    Grazing distribution management practices are intended to improve livestock production efficiency while conserving or enhancing environmental conditions, and sustaining or promoting other ecosystem services on grazed lands. Ancient practices such as herding, fencing, vegetation treatment (e.g., fi...

  17. Enhanced backscattering at grazing angles.

    PubMed

    Gu, Zu-Han; Fuks, I M; Ciftan, Mikael

    2002-12-02

    Backscattering signals at small grazing angles are important for space vehicle atmospheric reentrance and subsurface radar sensing applications. They are also useful in Fourier-transform infrared grazing-angle microscopy. Recently we performed an experimental study of far-field scattering at small grazing angles, in particular, of enhanced backscattering at grazing angles. For a randomly weak rough dielectric film upon a reflecting metal substrate, a large enhanced backscattering peak was measured. Experimental results are compared with small perturbation theoretical predictions.

  18. 25 CFR 700.709 - Grazing privileges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Grazing privileges. 700.709 Section 700.709 Indians THE... Grazing § 700.709 Grazing privileges. (a) A list of permittees eligible to receive grazing permits is kept... individuals eligible for New Lands grazing permits who: (1) Have a current HPL grazing permit, or have had...

  19. 25 CFR 700.709 - Grazing privileges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Grazing privileges. 700.709 Section 700.709 Indians THE... Grazing § 700.709 Grazing privileges. (a) A list of permittees eligible to receive grazing permits is kept... individuals eligible for New Lands grazing permits who: (1) Have a current HPL grazing permit, or have had...

  20. Grazing in central hardwood forests

    Treesearch

    Robert A. McQuilkin; Harold Scholten

    1989-01-01

    Woodland grazing is a major forestry and land management problem in parts of the central hardwood region. Most forest grazing is by cattle and, to a lesser extent, hogs in woodlands adjacent to pastures or feedlots. The practice is particularly common in the cattle producing areas of the Corn Belt where often 50 percent or more of the upland forest is grazed. Woodland...

  1. Grazing: the whole picture

    USDA-ARS?s Scientific Manuscript database

    Environmental concerns for our farms include nutrient leaching to ground water, runoff in surface water, gaseous emissions, and the carbon footprint of our production systems. Recent reports have labeled grazing-based dairies as less environmentally sustainable compared to year around confinement sy...

  2. Using Near Infrared Spectroscopy to Rapidly Ascertain Seedling Establishment Potential in Red Clover Breeding Programs

    USDA-ARS?s Scientific Manuscript database

    Establishing and maintaining forage legumes in grazed pastures is important to many grazing operations. To ascertain plant breeding progress in red clover (Trifolium pratense) over the past 50 years, persistence under rotational grazing in mixture with tall fescue (Festuca arundinacea) of 220 red cl...

  3. [Grazing resistance of rangeland plants].

    PubMed

    Wang, Shiping

    2004-03-01

    Grazing resistance is the relative ability of plants to survive and grow in grazed systems, which can be divided into avoidance and tolerance components, based on the general mechanisms conferring resistance. The studies of resistance and tolerance thresholds will explain the reasons and mechanisms of grazing succession of plant communities. The difference of species resistant and tolerant thresholds depends on their grazing resistance strategies. Although both mechanisms are known to occur, the predominant mechanism or relative combination of mechanisms remains unknown for most species combinations and plant communities. Recognition of grazing avoidance or tolerance as the predominant resistance strategy inducing species composition shifts has important implications for grassland and pasture management.

  4. Earth atmosphere grazing meteors

    NASA Astrophysics Data System (ADS)

    Kozak, P.

    2017-06-01

    An overview of described in literature earth atmosphere grazing meteors observed with optic methods is proposed. Results of observations of such a meteor detected in Kyiv on 23 September 2003 with super-isocon TV cameras are described. Kinematic parameters of the meteor trajectory in earth atmosphere and its heliocentric orbit elements are given. The comparative analysis of other meteor catalogues for presence in them and a number of such anomalous meteors is carried out.

  5. Effect of forage legumes and anthelmintic treatment on the performance, nutritional status and nematode parasites of grazing lambs.

    PubMed

    Marley, C L; Fraser, M D; Fychan, R; Theobald, V J; Jones, R

    2005-08-10

    Recent studies in New Zealand and the UK have shown that certain forages reduce parasitic infection in sheep. The aim of this experiment was to investigate the effects of legume forages compared to ryegrass on interactions between production, nutritional status and nematodes in grazing lambs. Twenty-four male lambs per forage treatment, half of which were treated with anthelmintics on Day 0, grazed monocultures of lucerne (Medicago sativa), red clover (Trifolium pratense) and white clover (Trifolium repens) and were compared with lambs grazing perennial ryegrass (Lolium perenne). Individual faecal egg counts (FEC) and liveweight were determined every 7 days for 56 days, after which half the lambs were slaughtered to determine total nematode intensities (TNI). Results showed that lambs grazed on red or white clover, but not lucerne, had lower pooled mean FEC and improved liveweight performance compared to lambs grazing ryegrass. Lambs treated with anthelmintics had higher TNI compared to lambs not treated, due to a trend for more adult nematodes in lambs grazing lucerne and treated with anthelmintics than all other lambs, except those grazing red clover and also given anthelmintics. Lambs grazing white clover tended to have fewer adult nematodes than lambs grazing other forages. Examination of the nematode species showed a change in female T. circumcincta occurred in all lambs following anthelmintic treatment and that the forage species grazed by lambs affected individual parasite species. Lambs grazing white clover had fewer male and adult T. circumcincta compared to lambs grazing other forages, and lambs grazing lucerne had fewer adult T. circumcincta compared to lambs grazing ryegrass or red clover. Data on small intestine TNI showed that lambs grazing lucerne and given anthelmintics had more male adult nematodes than other lambs, except those grazing red clover and treated with anthelmintics. Results indicate that lucerne and red clover both increase the re

  6. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Grazing permits. 700.711 Section 700.711 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing...

  7. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Grazing permits. 700.711 Section 700.711 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing...

  8. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Grazing permits. 700.711 Section 700.711 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing...

  9. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing... residency on the New Lands Range Unit of permit issue, and (4) Own livestock which graze on the range unit...

  10. 25 CFR 167.12 - Grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing fees. 167.12 Section 167.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.12 Grazing fees. Grazing fees shall not be charged at this time. 1 1 Grazing Committees were organized in May...

  11. Grazing management effects on pasture productivity – timing of grazing

    USDA-ARS?s Scientific Manuscript database

    What is the potential impact of more frequent grazing during particular times of the year? A range of grazing management systems was implemented at the U.S. Dairy Forage Research Center at Prairie du Sac, Wisconsin, on 1.0 acre paddocks of meadow fescue, orchardgrass, quackgrass, and reed canarygras...

  12. Adaptive grazing management experiment: The new frontier of grazing management

    USDA-ARS?s Scientific Manuscript database

    The Adaptive Grazing Management experiment at the USDA-ARS Central Plains Experimental Range addresses important gaps in our current understanding of grazing management including: 1) lack of management-science partnerships to more fully understand the effect of management decisions, 2) need for mana...

  13. Experimental evidence that livestock grazing intensity affects the activity of a generalist predator

    NASA Astrophysics Data System (ADS)

    Villar, Nacho; Lambin, Xavier; Evans, Darren; Pakeman, Robin; Redpath, Steve

    2013-05-01

    Grazing by domestic ungulates has substantial impacts on ecosystem structure and composition. In grasslands of the northern hemisphere, livestock grazing limits populations of small mammals, which are a main food source for a variety of vertebrate predators. However, no experimental studies have described the impact of livestock grazing on vertebrate predators. We experimentally manipulated sheep and cattle grazing intensity in the Scottish uplands to test its impact on a relatively abundant small mammal, the field vole (Microtus agrestis), and its archetypal generalist predator, the red fox (Vulpes vulpes). We demonstrate that ungulate grazing had a strong consistent negative impact on both vole densities and indices of fox activity. Ungulate grazing did not substantially affect the relationship between fox activity and vole densities. However, the data suggested that, as grazing intensity increased i) fox activity indices tended to be higher when vole densities were low, and ii) the relationship between fox activity and vole density was weaker. All these patterns are surprising given the relative small scale of our experiment compared to large red fox territories in upland habitats of Britain, and suggest that domestic grazing intensity causes a strong response in the activity of generalist predators important for their conservation in grassland ecosystems.

  14. Simulating rotational grazing management.

    PubMed

    Cros, M J; Duru, M; Garcia, F; Martin-Clouaire, R

    2001-09-01

    Dairy systems predominantly based on rotational grazing are notoriously hard to manage. In order to ensure profitability, this type of production requires quite good organisation, planning, and operating capability on the part of the farmer. A simulation-based decision support system, called SEPATOU, has been developed for this purpose. At the core of the decision support approach lies an explicit and rigorous modelling of the management strategy that underlies a dairy farmer's decision-making behaviour (real or hypothetical). The SEPATOU system is a discrete-event simulator that reproduces the day-to-day dynamics of the farmer's decision process and the response of the controlled biophysical system for which models of grass growth, animal consumption, and milk production are used. SEPATOU provides the means to evaluate and compare tentative strategies by simulating their application throughout the production season under different hypothetical weather conditions. The relative worth of a strategy can be assessed by analysing the effects on the biophysical system and their variability across the representative range of possible conditions that is considered. The activities to be managed concern the type and amount of conserved feed, where to fertilise and how much, the choice of fields to harvest, and most importantly, which field to graze next. Typically, SEPATOU is designed to be used by extension services and farming system scientists. It is implemented in C++ and is currently undergoing a validation process with the intended users.

  15. Cattle Grazing in Delta Forests

    Treesearch

    Robert L. Johnson

    1960-01-01

    What effects do grazing cattle have on the hardwood forests of the Mississippi Delta? What is the value of the forage to the cattle? To answer such questions, grazing studies were conducted in 1957 on the Delta Experimental Forest, near Stoneville.

  16. Mob grazing for dairy cows

    USDA-ARS?s Scientific Manuscript database

    Proponents of mob grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 lb/ac of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management technique is appropriate for dair...

  17. How Supplementation Affects Grazing Behavior

    USDA-ARS?s Scientific Manuscript database

    Researchers are still in the early stages of understanding how supplementation affects grazing behavior. Conventional nutrition wisdom, including early research with grazing cattle, has been based almost entirely upon stored feeds fed in confinement. In these situations, most dietary “choices” were ...

  18. Grazing management for healthy watersheds

    Treesearch

    Karl Wood

    2008-01-01

    (Please note, this is an abstract only) New Mexico was historically grazed by many native and introduced ungulates, often called wildlife. Their distribution was limited especially in deserts until domestic animals were introduced and drinking water was provided. Plants respond to grazing with little resistance (black grama), to great resistance (blue grama), and to...

  19. Grazing incidence beam expander

    SciTech Connect

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  20. Grazing incidence beam expander

    NASA Astrophysics Data System (ADS)

    Akkapeddi, P. R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V. K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  1. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing permits. 167.9 Section 167.9 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.9 Grazing permits. (a) All livestock grazed on the Navajo Reservation must be covered by an authorized...

  2. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing permits. 167.9 Section 167.9 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.9 Grazing permits. (a) All livestock grazed on the Navajo Reservation must be covered by an authorized...

  3. Livestock grazing not detrimental to meadow wildflowers

    Treesearch

    Raymond D. Ratliff

    1972-01-01

    Wildflower growth, meadow conditions, and grazing methods were compared in the Bogard area, Lassen National Forest, northeastern California. The two grazing methods were rest-rotation, in which range units are periodically rested from grazing, and free-choice, in which range units are not provided any rest periods from use. The results suggest that grazing per se need...

  4. Grazing Incidence Optics Technology

    NASA Technical Reports Server (NTRS)

    Ramsey, Brian; Smith, W. Scott; Gubarev, Mikhail; McCracken, Jeff

    2015-01-01

    This project is to demonstrate the capability to directly fabricate lightweight, high-resolution, grazing-incidence x-ray optics using a commercially available robotic polishing machine. Typical x-ray optics production at NASA Marshall Space Flight Center (MSFC) uses a replication process in which metal mirrors are electroformed on to figured and polished mandrels from which they are later removed. The attraction of this process is that multiple copies can be made from a single master. The drawback is that the replication process limits the angular resolution that can be attained. By directly fabricating each shell, errors inherent in the replication process are removed. The principal challenge now becomes how to support the mirror shell during all aspects of fabrication, including the necessary metrology to converge on the required mirror performance specifications. This program makes use of a Zeeko seven-axis computer-controlled polishing machine (see fig. 1) and supporting fabrication, metrology, and test equipment at MSFC. The overall development plan calls for proof-of-concept demonstration with relatively thick mirror shells (5-6 mm, fig. 2) which are straightforward to support and then a transition to much thinner shells (2-3 mm), which are an order of magnitude thinner than those used for Chandra. Both glass and metal substrates are being investigated. Currently, a thick glass shell is being figured. This has enabled experience to be gained with programming and operating the polishing machine without worrying about shell distortions or breakage. It has also allowed time for more complex support mechanisms for figuring/ polishing and metrology to be designed for the more challenging thinner shells. These are now in fabrication. Figure 1: Zeeko polishing machine.

  5. Monitoring grazing intensity: an experiment with canopy spectra applied to satellite remote sensing

    NASA Astrophysics Data System (ADS)

    Li, Fei; Zhao, Ying; Zheng, Jiajia; Luo, Juhua; Zhang, Xiaoqiang

    2016-04-01

    The quantification of grassland grazing intensity (GI) and its detailed spatial distribution are important for grassland management and ecological protection. Remote sensing has great potential in these areas, but its use is still limited. This study analyzed the impacts of grazing on biophysical properties of vegetation and suggested using biomass to quantify GI because of its stability and interpretability. In comparison to a single spectral index, such as the red edge index (REI), combining REI and a cellulose absorption ratio index calculated from hyperspectral data performs better for biomass estimation. Further, an auxiliary spectral index, called the grazing monitoring index (GMI), was developed based on differences in spectral reflectance in the infrared range. Experiments in a grazing area of the Inner Mongolia grassland indicated that GMI can identify GI, with three range intervals (GMI <0, 0-1, and ≥1) used to describe the biomass distribution. The results showed that combining GMI and biomass was more successful than existing approaches for identifying the grassland variability resulting from the spatial heterogeneity of grazing behavior. The thresholds of biomass for four GI levels (ungrazed, lightly grazed, moderately grazed, and heavily grazed) could be determined by the intersections of biomass distributions. In addition, the approach developed at the on-ground canopy scale was extended to remotely sensed Hyperion data. The results showed that the approach could successfully identify the grazing treatments of blocks in the experimental grazing area. Overall, our study provides inspiration and ideas for using satellite remote sensing for evaluating plant production, standing biomass, and livestock impacts.

  6. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the purposes... the project engineer. ...

  7. Rotational grazing systems and grazing management research: Mapping the future

    USDA-ARS?s Scientific Manuscript database

    A recent publication reviewed a substantial amount of evidence generated from a geographically diverse effort by university and agency scientists over the past 6 decades to investigate the impacts of rotational grazing on fundamental rangeland ecological processes. Their findings, and others as well...

  8. Effects of grazing intensity and chemical seedhead suppression on steers grazing tall fescue pastures

    USDA-ARS?s Scientific Manuscript database

    The first year of a 2 yr grazing study was conducted to evaluate use of Chaparral™ to suppress reproductive growth in tall fescue grazed with low and moderate grazing intensities. Chaparral applications (0 and 2.0 oz/acre) and grazing intensities were arranged as RCBD with three replications. Variab...

  9. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  10. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  11. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  12. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  13. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of each...

  14. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of each...

  15. Livestock grazing, wildlife habitat, and rangeland values

    Treesearch

    Paul R. Krausman; David E. Naugle; Michael R. Frisina; Rick Northrup; Vernon C. Bleich; William M. Block; Mark C. Wallace; Jeffrey D. Wright

    2009-01-01

    Livestock managers make and implement grazing management decisions to achieve a variety of objectives including livestock production, sustainable grazing, and wildlife habitat enhancement. Assessed values of grazing lands and ranches are often based on aesthetics and wildlife habitat or recreational values, which can exceed agricultural values, thus providing...

  16. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  17. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  18. 25 CFR 168.8 - Grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing fees. 168.8 Section 168.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.8 Grazing fees. (a) The rental value of all uses of Hopi Partitioned lands by...

  19. 43 CFR 4110.2 - Grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing preference. 4110.2 Section 4110.2..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2 Grazing preference....

  20. 25 CFR 168.8 - Grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing fees. 168.8 Section 168.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.8 Grazing fees. (a) The rental value of all uses of Hopi Partitioned lands by...

  1. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  2. 50 CFR 35.9 - Livestock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Livestock grazing. 35.9 Section 35.9 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE... grazing. (a) The grazing of livestock, where established prior to the date of legislation which...

  3. Theory of grazing electromagnetic induction

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Guerrero, Juan F.

    2016-11-01

    We calculate the emf produced when a square loop grazes a point dipole, moving parallel to it. To do this we combine analytical and numerical work. An emf signal with a three-peak structure which was previously observed is thus explained, while other signal forms are predicted.

  4. Grazing effects on grassland ecosystems

    Treesearch

    Linda L. Wallace; Mel I. Dyer

    1996-01-01

    In this study, we used a modified version of a meta-analysis (compilation and analysis of the literature in which an individual area is subjected to the disturbance and its response is noted) to analyze grazing effects on grassland ecosystems. Prior efforts have focused on one aspect of ecosystem behavior such as productivity or species diversity. In this analysis, we...

  5. Effects of soil amendments and severe cattle grazing on the long-term survival and growth of tree seedlings on eastern Kentucky surface mined land

    SciTech Connect

    Ringe, J.M.; Graves, D.H.; Wittwer, R.F.

    1984-12-01

    Seedlings of Virginia pine, European alder, and northern red oak were planted in March of 1977 under three bark mulch depths and three diammonium phosphate fertilizer rates, with and without grass-legume competition. In 1983, cattle were allowed to graze in the study area. The trees were remeasured in March of 1984 to determine the longer-term effects of the soil amendments and the effects of cattle grazing on tree survival and height growth. Both of these parameters increased under bark mulch and fertilizer, but decreased under herbaceous competition. Survival and growth also decreased following grazing. Additionally, cattle grazing had a highly detrimental effect on tree form.

  6. Response of a subalpine grassland to simulated grazing: Aboveground productivity along soil phosphorus gradients

    Treesearch

    C. Thiel-Egenter; A. C. Risch; M. F. Jurgensen; D. S. Page-Dumroese; B. O. Krusi; M. Schutz

    2007-01-01

    Interactions between grassland ecosystems and vertebrate herbivores are critical for a better understanding of ecosystem processes, but diverge widely in different ecosystems. In this study, we examined plant responses to simulated red deer (Cervus elaphus L.) grazing using clip-plot experiments in a subalpine grassland ecosystem of the Central...

  7. Ecology of grazing lawns in Africa.

    PubMed

    Hempson, Gareth P; Archibald, Sally; Bond, William J; Ellis, Roger P; Grant, Cornelia C; Kruger, Fred J; Kruger, Laurence M; Moxley, Courtney; Owen-Smith, Norman; Peel, Mike J S; Smit, Izak P J; Vickers, Karen J

    2015-08-01

    Grazing lawns are a distinct grassland community type, characterised by short-stature and with their persistence and spread promoted by grazing. In Africa, they reveal a long co-evolutionary history of grasses and large mammal grazers. The attractiveness to grazers of a low-biomass sward lies in the relatively high quality of forage, largely due to the low proportion of stem material in the sward; this encourages repeat grazing that concomitantly suppresses tall-grass growth forms that would otherwise outcompete lawn species for light. Regular grazing that prevents shading and maintains sward quality is thus the cornerstone of grazing lawn dynamics. The strong interplay between abiotic conditions and disturbance factors, which are central to grazing lawn existence, can also cause these systems to be highly dynamic. Here we identify differences in growth form among grazing lawn grass species, and assess how compositional differences among lawn types, as well as environmental variables, influence their maintenance requirements (i.e. grazing frequency) and vulnerability to degradation. We also make a clear distinction between the processes of lawn establishment and lawn maintenance. Rainfall, soil nutrient status, grazer community composition and fire regime have strong and interactive influences on both processes. However, factors that concentrate grazing pressure (e.g. nutrient hotspots and sodic sites) have more bearing on where lawns establish. Similarly, we discuss the relevance of enhanced rates of nitrogen cycling and of sodium levels to lawn maintenance. Grazer community composition and density has considerable significance to grazing lawn dynamics; not all grazers are adapted to foraging on short-grass swards, and differences in body size and relative mouth dimensions determine which species are able to convert tall-grass swards into grazing lawns under different conditions. Hence, we evaluate the roles of different grazers in lawn dynamics, as well as the

  8. Replication of grazing incidence optics

    NASA Technical Reports Server (NTRS)

    Ulmer, Melville P.

    1986-01-01

    The replication of grazing incidence optics is reviewed. Electroform and epoxy replication are described and compared. It is concluded that for light weight and deep nesting, replication has a distinct advantage over direct production. The resolution of optics produced in this manner is however, limited to about 10 arc seconds; a typical value is 40 arc seconds. Epoxy replicated pieces tend to have better optical figures than electroformed optics, but the latter can be made thinner to make more deeply nested systems.

  9. Aberrations for Grazing Incidence Optics

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.

    2008-01-01

    Large number of grazing incidence telescope configurations have been designed and studied. Wolte1 telescopes are commonly used in astronomical applications. Wolter telescopes consist of a paraboloidal primary mirror and a hyperboloidal or an ellipsoidal secondary mirror. There are 8 possible combinations of Wolter telescopes. Out of these possible designs only type 1 and type 2 telescopes are widely used. Type 1 telescope is typically used for x-ray applications and type 2 telescopes are used for EUV applications. Wolter-Schwarzshild (WS) telescopes offer improved image quality over a small field of view. The WS designs are stigmatic and free of third order coma and, therefore, the PSF is significantly better over a small field of view. Typically the image is more symmetric about its centroid. As for the Wolter telescopes there are 8 possible combinations of WS telescopes. These designs have not been widely used because the surface equations are complex parametric equations complicating the analysis and typically the resolution requirements are too low to take full advantage of the WS designs. There are several other design options. Most notable are wide field x-ray telescope designs. Polynomial designs were originally suggested by Burrows4 and hyperboloid-hyperboloid designs for solar physics applications were designed by Harvey5. No general aberration theory exists for grazing incidence telescopes that would cover all the design options. Several authors have studied the aberrations of grazing incidence telescopes. A comprehensive theory of Wolter type 1 and 2 telescopes has been developed. Later this theory was expanded to include all possible combinations of grazing incidence and also normal incidence paraboloid-hyperboloid and paraboloid-ellipsoid telescopes. In this article the aberration theory of Wolter type telescopes is briefly reviewed.

  10. Near anastigmatic grazing incidence telescope

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1984-01-01

    A performance capability assessment is presently conducted for short versus long grazing incidence telescope designs, in view of the observation that the field curvature and astigmatism that are the primary residual aberrations of a Wolter-type incidence telescope can be substantially reduced through mirror length reduction. A major advantage of the short element telescope is that, if sufficiently short, both the paraboloid and hyperboloid surfaces may be fabricated as a single piece; this significantly facilitates the task of alignment.

  11. Replication of grazing incidence optics

    NASA Technical Reports Server (NTRS)

    Ulmer, Melville P.

    1986-01-01

    The replication of grazing incidence optics is reviewed. Electroform and epoxy replication are described and compared. It is concluded that for light weight and deep nesting, replication has a distinct advantage over direct production. The resolution of optics produced in this manner is however, limited to about 10 arc seconds; a typical value is 40 arc seconds. Epoxy replicated pieces tend to have better optical figures than electroformed optics, but the latter can be made thinner to make more deeply nested systems.

  12. Near anastigmatic grazing incidence telescope

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1984-01-01

    A performance capability assessment is presently conducted for short versus long grazing incidence telescope designs, in view of the observation that the field curvature and astigmatism that are the primary residual aberrations of a Wolter-type incidence telescope can be substantially reduced through mirror length reduction. A major advantage of the short element telescope is that, if sufficiently short, both the paraboloid and hyperboloid surfaces may be fabricated as a single piece; this significantly facilitates the task of alignment.

  13. Light quality and not quantity segregates germination of grazing increasers from decreasers in Mediterranean grasslands

    NASA Astrophysics Data System (ADS)

    Dobarro, Iker; Valladares, Fernando; Peco, Begoña

    2010-01-01

    Grassland plant species have traditionally been classified into two groups, increasers and decreasers, based on changes in their relative abundance in the presence or absence of grazing. However, the ecophysiological mechanisms underlying these opposing strategies remain unclear. Seeds of ten Mediterranean species of known grazing status were germinated in different light environments to test the hypothesis that grazing selects light-dependent germination amongst grazing increasers. Two light quantity levels (Photosynthetical Active Radiation, PAR) and five light quality levels (red:far-red ratio, R:FR) were used to quantify percentages of germination of viable seeds and number of days elapsed to reach 50% of germination (T50), measured using five replicates of each light treatment and species combination. There were no differences in response to light quantity between the two grazing status groups; germination was inhibited in both groups at higher light intensities. However, increasers had lower germination percentages at low R:FR ratios, while decreasers were not affected by light quality. Germination speed (T50) was affected differently by light quality in each grazing status. There was an increase in germination speed at the lowest R:FR ratio only in increaser seeds, whereas decreaser germination speed was not affected by the treatment. PAR affected T50, regardless of grazing status; germination was faster at lower light intensities. Increaser seeds germinated faster than decreasers. These results reveal that the differential control of germination by light quality is a key factor in determining the species composition of grassland plant communities affected by herbivores in semi-arid Mediterranean grasslands.

  14. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits is...

  15. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits is...

  16. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits is...

  17. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits is...

  18. 43 CFR 4130.6 - Other grazing authorizations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Other grazing authorizations. 4130.6... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6 Other grazing authorizations. Exchange-of-use grazing...

  19. 25 CFR 700.713 - Tenure of grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Tenure of grazing permits. 700.713 Section 700.713... New Lands Grazing § 700.713 Tenure of grazing permits. (a) All active regular grazing permits shall be... grazing permits are applicable and become a condition of all previously granted permits....

  20. 43 CFR 4130.2 - Grazing permits or leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing permits or leases. 4130.2 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.2 Grazing permits or leases. (a) Grazing permits and leases authorize use...

  1. Infrared microanalysis of contaminants at grazing incidence

    NASA Astrophysics Data System (ADS)

    Reffner, John A.

    1991-04-01

    A new objective lens for grazing angle FT-IR microscopy provides a means for the infrared analysis of monomolecular films in small (25 X 25 micrometers ) areas. Conventional grazing incidence reflection spectroscopy is an established technology for detecting and analyzing thin surface films on metals or highly reflecting materials. The grazing incidence objective extends these techniques to microscopic areas. Applications of grazing angle FT-IR microscopy (GAM) are illustrated by exemplar analyses. The analyses of thin film lubricants and contaminants are specially important.

  2. Guild structure of a riparian avifauna relative to seasonal cattle grazing

    USGS Publications Warehouse

    Knopf, F.L.; Sedgwick, J.A.; Cannon, R. W.

    1988-01-01

    Knopf et al. found that summer cattle grazing has an adverse effect on the presence of certain willow-dependent songbirds. Pastures that have historical summer grazing no longer have the Willow flycatcher, Lincoln's sparrow and the White-crowned sparrow present. Yet in these same areas, birds like the American Robin, Brown-headed cowbird and the Red-winged blackbird have increased in density. One possible answer for the decrease in some songbirds is the fact that the main focus of the Arapaho National Wildlife Refuge is on waterfowl habitat, which requires large amounts of open space (opposite of desirable songbird habitat).

  3. CLOSE STELLAR BINARY SYSTEMS BY GRAZING ENVELOPE EVOLUTION

    SciTech Connect

    Soker, Noam

    2015-02-20

    I suggest a spiral-in process in which a stellar companion grazes the envelope of a giant star while both the orbital separation and the giant radius shrink simultaneously, forming a close binary system. The binary system might be viewed as evolving in a constant state of 'just entering a common envelope (CE) phase.' In cases where this process takes place, it can be an alternative to CE evolution where the secondary star is immersed in the giant's envelope. Grazing envelope evolution (GEE) is made possible only if the companion manages to accrete mass at a high rate and launches jets that remove the outskirts of the giant envelope, hence preventing the formation of a CE. The high accretion rate is made possible by the accretion disk launching jets which efficiently carry the excess angular momentum and energy from the accreted mass. The orbital decay itself is caused by the gravitational interaction of the secondary star with the envelope inward of its orbit, i.e., dynamical friction (gravitational tide). Mass loss through the second Lagrangian point can carry additional angular momentum and envelope mass. The GEE lasts for tens to hundreds of years. The high accretion rate, with peaks lasting from months to years, might lead to a bright object referred to as the intermediate luminosity optical transient (Red Novae; Red Transients). A bipolar nebula and/or equatorial ring are formed around the binary remnant.

  4. Waterfowl production in relation to grazing

    USGS Publications Warehouse

    Kirsch, L.M.

    1969-01-01

    A 4-year production study of upland nesting waterfowl on the Missouri Coteau area of North Dakota showed that pair numbers, nesting densities and nest success were generally reduced by grazing. It is suggested that cover removal such as regular grazing and mowing be discontinued on areas managed primarily for waterfowl production and that management practices which create dense rank cover be substituted.

  5. The Fundamentals of a Managed Grazing Program

    USDA-ARS?s Scientific Manuscript database

    The underlying principle of a managed grazing program is to manage livestock in a manner that controls the timing and extent of grazing of forage plants so that the pasture provides a reliable source of forage of the appropriate quality throughout the growing season. Control of when, how often, and...

  6. Livestock grazing and wildlife: developing compatabilities.

    Treesearch

    Martin. Vavra

    2005-01-01

    Livestock grazing has been considered detrimental to wildlife habitat. Managed gazing programs, however, have the potential to maintain habitat diversity and quality. In cases in which single-species management predominates (sage-grouse [Centrocercus urophasianus] or elk [Cervus elaphus nelsoni] winter range), grazing systems...

  7. Predicting forage intake by grazing beef cattle

    USDA-ARS?s Scientific Manuscript database

    Voluntary intake by cattle is controlled by a complex mix of physical and physiological factors that interact with a variety of environmental, geo-spatial, and experiential influences external to the animal. These factors are intensified in grazing ruminants, where selective grazing and variability...

  8. Grazing function g and collimation angular acceptance

    SciTech Connect

    Peggs, S.G.; Previtali, V.

    2009-11-02

    The grazing function g is introduced - a synchrobetatron optical quantity that is analogous (and closely connected) to the Twiss and dispersion functions {beta}, {alpha}, {eta}, and {eta}'. It parametrizes the rate of change of total angle with respect to synchrotron amplitude for grazing particles, which just touch the surface of an aperture when their synchrotron and betatron oscillations are simultaneously (in time) at their extreme displacements. The grazing function can be important at collimators with limited acceptance angles. For example, it is important in both modes of crystal collimation operation - in channeling and in volume reflection. The grazing function is independent of the collimator type - crystal or amorphous - but can depend strongly on its azimuthal location. The rigorous synchrobetatron condition g = 0 is solved, by invoking the close connection between the grazing function and the slope of the normalized dispersion. Propagation of the grazing function is described, through drifts, dipoles, and quadrupoles. Analytic expressions are developed for g in perfectly matched periodic FODO cells, and in the presence of {beta} or {eta} error waves. These analytic approximations are shown to be, in general, in good agreement with realistic numerical examples. The grazing function is shown to scale linearly with FODO cell bend angle, but to be independent of FODO cell length. The ideal value is g = 0 at the collimator, but finite nonzero values are acceptable. Practically achievable grazing functions are described and evaluated, for both amorphous and crystal primary collimators, at RHIC, the SPS (UA9), the Tevatron (T-980), and the LHC.

  9. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The...

  10. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The...

  11. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The...

  12. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The...

  13. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 Grazing activities. The...

  14. MEASURING INVERTEBRATE GRAZING ON SEAGRASSES AND EPIPHYTES

    EPA Science Inventory

    The chapter describes methods to assess grazing rates, grazer preferences, and grazer impacts, by mobile organisms living in the canopy or in the rhizome layer in any seagrass system. One set of methods quantifies grazing activity in small to medium sized, mobile organisms livin...

  15. MEASURING INVERTEBRATE GRAZING ON SEAGRASSES AND EPIPHYTES

    EPA Science Inventory

    The chapter describes methods to assess grazing rates, grazer preferences, and grazer impacts, by mobile organisms living in the canopy or in the rhizome layer in any seagrass system. One set of methods quantifies grazing activity in small to medium sized, mobile organisms livin...

  16. Rotational grazing systems and livestock grazing behavior in shrub-dominated semi-arid and arid rangelands

    USDA-ARS?s Scientific Manuscript database

    Rotational grazing systems (RGS) are often implemented to alleviate undesirable selective grazing by livestock. At both fine and coarse scales, livestock selectively graze individual plants, patches, communities, and landscapes. Smaller pastures, increased stocking density, and rotation allow manage...

  17. Productivity and hay requirements of beef cattle in a Midwestern year-round grazing system.

    PubMed

    Janovick, N A; Russell, J R; Strohbehn, D R; Morrical, D G

    2004-08-01

    Our objective was to evaluate a replicated (n = 2) Midwestern year-round grazing system's hay needs and animal production compared with a replicated (n = 2) conventional (minimal land) system over 3 yr. Because extended grazing systems have decreased hay needs for the beef herd, it was hypothesized that this year-round system would decrease hay needs without penalizing animal production. In the minimal land (ML) system, two replicated 8.1-ha smooth bromegrass-orchardgrass-birdsfoot trefoil (SB-OG-BFT) pastures were rotationally stocked with six mature April-calving cows and calves and harvested as hay for winter feeding in a drylot. After weaning, calves were finished on a high-concentrate diet. Six mature April-calving cows, six mature August-calving cows, and their calves were used in the year-round (YR) grazing system. During the early and late summer, cattle grazed two replicated 8.1-ha SB-OG-BFT pastures by rotational stocking. In mid-summer and winter, April- and August-calving cows grazed two replicated 6.1-ha, endophyte-free tall fescue-red clover (TF-RC) and smooth bromegrass-red clover (SB-RC) pastures, respectively, by strip-stocking. In late autumn, spring-calving cows grazed 6.1-ha corn crop residue fields by strip-stocking. Calves were fed hay with corn gluten feed or corn grain over winter and used as stocker cattle to graze SB-OG-BFT pastures with cows until early August the following summer. First-harvest forage from the TF-RC and SB-RC pastures was harvested as hay. Body condition scores of April-calving cows did not differ between grazing systems, but were lower (P < or = 0.03) than those of August-calving cows from mid-gestation through breeding. Preweaning calf BW gains were 47 kg/ha of perennial pasture (P < 0.01) and 32 kg/cow (P = 0.01) lower in the YR grazing system than in the ML system. Total BW gains ofpreweaning calf and grazing stocker cattle were 12 kg/ha of perennial pasture less (P = 0.07), but 27 kg/cow greater (P = 0.02) in

  18. 25 CFR 167.10 - Special grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Special grazing permits. 167.10 Section 167.10 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.10 Special grazing permits. The problem of special grazing permits shall be settled by the Bureau of...

  19. 25 CFR 700.719 - Establishment of grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Establishment of grazing fees. 700.719 Section 700.719... New Lands Grazing § 700.719 Establishment of grazing fees. The Commissioner may establish a minimum acceptable grazing fee per SUYL. The Commissioner may consult with the Tribe prior to establishing fees....

  20. 25 CFR 700.719 - Establishment of grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Establishment of grazing fees. 700.719 Section 700.719... New Lands Grazing § 700.719 Establishment of grazing fees. The Commissioner may establish a minimum acceptable grazing fee per SUYL. The Commissioner may consult with the Tribe prior to establishing fees....

  1. 25 CFR 167.11 - Tenure of grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Tenure of grazing permits. 167.11 Section 167.11 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.11 Tenure of grazing permits. (a) All active regular grazing permits shall be for one year and shall...

  2. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing of livestock. 293.7...-PRIMITIVE AREAS § 293.7 Grazing of livestock. (a) The grazing of livestock, where such use was established..., shall be permitted to continue under the general regulations covering grazing of livestock on...

  3. 25 CFR 167.11 - Tenure of grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Tenure of grazing permits. 167.11 Section 167.11 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.11 Tenure of grazing permits. (a) All active regular grazing permits shall be for one year and shall...

  4. 25 CFR 167.10 - Special grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Special grazing permits. 167.10 Section 167.10 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.10 Special grazing permits. The problem of special grazing permits shall be settled by the Bureau of...

  5. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Grazing of livestock. 293.7...-PRIMITIVE AREAS § 293.7 Grazing of livestock. (a) The grazing of livestock, where such use was established..., shall be permitted to continue under the general regulations covering grazing of livestock on...

  6. 43 CFR 4110.2-3 - Transfer of grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Transfer of grazing preference. 4110.2-3... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2-3 Transfer of grazing preference. (a) Transfers of grazing preference...

  7. 43 CFR 2711.4-1 - Grazing improvements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing improvements. 2711.4-1 Section... MANAGEMENT ACT Sales: Procedures § 2711.4-1 Grazing improvements. No public lands in a grazing lease or... authorized grazing improvements have been met....

  8. 43 CFR 4110.2-2 - Specifying grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Specifying grazing preference. 4110.2-2... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2-2 Specifying grazing preference. (a) All grazing permits and...

  9. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  10. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  11. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  12. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  13. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  14. 43 CFR 9239.3 - Grazing, Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... livestock upon, allowing livestock to drift and graze on, or driving livestock across lands that are subject... the public land and other property of the United States and shall make a demand for payment upon the...

  15. 43 CFR 9239.3 - Grazing, Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... livestock upon, allowing livestock to drift and graze on, or driving livestock across lands that are subject... the public land and other property of the United States and shall make a demand for payment upon the...

  16. 43 CFR 9239.3 - Grazing, Alaska.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... livestock upon, allowing livestock to drift and graze on, or driving livestock across lands that are subject... the public land and other property of the United States and shall make a demand for payment upon the...

  17. 43 CFR 9239.3 - Grazing, Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... livestock upon, allowing livestock to drift and graze on, or driving livestock across lands that are subject... the public land and other property of the United States and shall make a demand for payment upon the...

  18. 25 CFR 167.12 - Grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... respective districts with all of the various items of range administration and range management. Also the... assessment of grazing fees will not aid materially in obtaining proper range use. At this time it is more...

  19. 25 CFR 700.722 - Grazing associations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... association may hold a grazing permit to benefit its members according to the rules of the association constitution and bylaws. All of the association's livestock will be run under an association brand...

  20. 25 CFR 700.722 - Grazing associations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... association may hold a grazing permit to benefit its members according to the rules of the association constitution and bylaws. All of the association's livestock will be run under an association brand...

  1. Riparian-fisheries habitat responses to late spring cattle grazing

    Treesearch

    Warren P. Clary; John W. Kinney

    2000-01-01

    A grazing study was conducted on a cold, mountain meadow riparian system in central Idaho in response to cattle grazing-salmonid fisheries conflicts. Six pastures were established along a 3rd order, 2 to 3 m wide stream to study the effects on fisheries habitat of no grazing, light grazing (20 to 25% use), and medium grazing (35 to 50%) during late June. Most...

  2. Metabolic profile in Chilota lambs grazing Calafatal.

    PubMed

    Gallardo, María Asunción; Noro, Mirela; De la Barra, Rodrigo; Pulido, Rubén

    2014-04-01

    The aim of this study was to determine the productive and metabolic response in Chilota lambs grazing Calafatal or naturalized pasture. The experiment was conducted at the Experimental Station Butalcura (INIA, Chiloé) during October, November, and December 2011. Eight Chilota and six Suffolk Down 2-month-old lambs, uncastrated males, no twin, were located to graze a typical secondary succession of the Chiloé Archipelago, as a Calafatal (a secondary succession which derivates from human intervention on native forest in Chiloé Archipelago). Simultaneously, eight male 2-month-old Chilota lambs were located to graze a naturalized pasture, another secondary succession derived from human intervention on native forest in Chiloé Archipelago. Animals had free access to water sources. Measurements were performed one time a month, for three consecutive months for productive indicators: live weight, average daily gain and body condition score, and blood indicators of protein and energetic metabolism. Productive and metabolic response was similar between both types of pastures (P > 0.05). However, Chilota and Suffolk Down lambs grazing Calafatal showed higher plasma concentrations of βOH-butyrate, but lower non-esterified fatty acids (NEFA) than Chilota lambs grazing naturalized pasture (P < 0.05). Chilota lambs grazing naturalized pasture showed the highest plasma concentrations of NEFA and urea (P < 0.05). It was concluded that, under the conditions of the study, Chilota lambs grazing naturalized pasture, which had higher contents of crude protein and metabolizable energy, showed better metabolic balance, but not performance, than Chilota and Suffolk Down lambs grazing Calafatal.

  3. Properties And Performance Of Grazing Incidence Reflectors

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    We numerically analyze at near-grazing incidence various configurations containing elliptical, toroidal, and the recently proposed common-axis rotationally symmetric anamorphic (CARSA) elements to determine the type and importance of aberrations inherent in each. CARS pairs of elliptical mirrors are shown to have negligible focusing errors for typical synchrotron source dimensions, and therefore comprise useful building blocks from which to construct grazing-incidence optical systems. To minimize aberrations, cylindrical, spherical, or toroidal elements should be avoided.

  4. Properties and performance of grazing incidence reflectors

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    1982-05-01

    Various configurations containing elliptical, toroidal, and the recently proposed common-axis rotationally symmetric anamorphic (CARSA) elements are numerically analyzed at near-grazing incidence, to determine the type and importance of aberrations inherent in each. CARS pairs of elliptical mirrors are shown to have negligible focusing errors for typical synchrotron source dimensions, and therefore comprise useful building blocks from which to construct grazing-incidence optical systems. To minimize aberrations, cylindrical, spherical, or toroidal elements should be avoided.

  5. Magnetic alignment in grazing and resting cattle and deer.

    PubMed

    Begall, Sabine; Cerveny, Jaroslav; Neef, Julia; Vojtech, Oldrich; Burda, Hynek

    2008-09-09

    We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring "deer beds" in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north-south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.

  6. Magnetic alignment in grazing and resting cattle and deer

    PubMed Central

    Begall, Sabine; Červený, Jaroslav; Neef, Julia; Vojtěch, Oldřich; Burda, Hynek

    2008-01-01

    We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring “deer beds” in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms. PMID:18725629

  7. Resistance of nitrifiers inhabiting activated sludge to ciliate grazing.

    PubMed

    Pajdak-Stós, Agnieszka; Fiałkowska, Edyta; Fyda, Janusz; Babko, Roman

    2010-01-01

    We monitored the succession of nitrifiers in a newly opened wastewater treatment plant for five weeks. After the first distinct decrease in total nitrogen, we began monitoring the appearance, size and number of nitrifying bacteria colonies using the fluorescence in situ hybridization (FISH) method. Ammonia oxidizing bacteria (AOB) colonies were visualized under green excitation as red, and nitrite oxidizing bacteria (NOB) colonies were visualized under blue excitation as green. The changes in protozoan community were monitored simultaneously. Ciliates were divided into four functional groups: predatory, bacterivorous free-swimming, bacterivorous crawling, and sessile. The results showed that at the time of the first distinct total nitrogen decrease, the mean length of both AOB and NOB were relatively low, but the colonies, especially those of nitrite oxidizers, were abundant. In time, the distribution of ammonia oxidizer colonies shifted towards larger sizes, but their quantity decreased. In the case of nitrite oxidizers, a similar trend was noticeable but less pronounced. These changes corresponded with an increasing number of crawling bacterivorous ciliates dominated by the "scavenger" genus Aspidisca. The increasing size of nitrifier colonies may have been due to the growing grazing pressure from crawling bacterivorous ciliates. The strong grazing pressure did not negatively affect N-NH(4)(+) removal effectiveness.

  8. Reducing phosphorus inputs for grazing Holstein steers.

    PubMed

    Brokman, A M; Lehmkuhler, J W; Undersander, D J

    2008-03-01

    A 2-yr study was conducted to confirm that managed pastures can provide Holstein steers adequate P to meet their daily requirement. Treatments offered were trace mineralized salt with or without additional P. In the first year, 80 Holstein steers (248 kg of BW) were assigned to 4 grazing groups. Treatments were trace mineralized salt only or a 67:33 mixture of trace mineralized salt and dicalcium phosphate. Steers rotationally grazed a cool-season grass/legume mixture for 137 d. Fecal bags were placed on 3 steers from each grazing group (n = 12) over a 4-d period for estimation of forage DMI and forage contribution to daily P intake twice during the grazing season. Analyzed pasture samples contained 3.28 mg of P/g of DM. During the second year, 72 Holstein steers (297 kg of BW) were blocked into 2 BW groups and subsequently assigned to 1 of 4 pasture groups. Steers rotationally grazed the same forage base as the first year for 126 d. Pasture samples contained 3.27 mg of P/g of DM. No significant differences (P > 0.10) were detected for BW, ADG, or free-choice supplemental mineral intake. Forage provided 126% of the recommended NRC P requirement. Thus, supplemental phosphorous was not required for Holstein steers grazing mixed, cool-season, grass/legume pastures.

  9. Effects of anthropogenic fragmentation and livestock grazing on western riparian bird communities

    USGS Publications Warehouse

    Tewksbury, J.J.; Black, A.E.; Nur, N.; Saab, V.A.; Logan, B.D.; Dobkin, D.S.

    2002-01-01

    Deciduous vegetation along streams and rivers provides breeding habitat to more bird species than any other plant community in the West, yet many riparian areas are heavily grazed by cattle and surrounded by increasingly developed landscapes. The combination of cattle grazing and landscape alteration (habitat loss and fragmentation) are thought to be critical factors affecting the richness and composition of breeding bird communities. Here, we examine the influence of land use and cattle grazing on deciduous riparian bird communities across seven riparian systems in five western states: Montana, Idaho, Nevada, Oregon and California. These riparian systems are embedded in landscapes ranging from nearly pristine to almost completely agricultural. We conducted landscape analysis at two spatial scales: local landscapes (all land within 500 m of each survey location) and regional landscapes (all land within 5 km of each survey location). Despite the large differences among riparian systems, we found a number of consistent effects of landscape change and grazing. Of the 87 species with at least 15 detections on two or more rivers, 44 species were less common in grazed sites, in heavily settled or agricultural landscapes, or in areas with little deciduous riparian habitat. The Veery (Catharus fuscescens), Song Sparrow (Melospiza melodia), Red-naped Sapsucker (Sphyrapicus nuchalis), Fox Sparrow (Passerella iliaca), and American Redstart (Setophaga ruticilla) were all less common under at least three of these conditions. In contrast, 33 species were significantly more common in one or more of these conditions. Sites surrounded by greater deciduous habitat had higher overall avian abundance and 22 species had significantly higher individual abundances in areas with more deciduous habitat. Yet, areas with more agriculture at the regional scale also had higher total avian abundance, due in large part to greater abundance of European Starling (Sturnus vulgaris), American Robin

  10. Grazing activity and ruminal bacterial population associated with frothy bloat in steers grazing winter wheat

    USDA-ARS?s Scientific Manuscript database

    Two grazing experiments were designed to elucidate the shifts in rumen bacterial populations (Exp. 1) and grazing activities (Exp. 2) in wheat forage diets between bloated and non-bloated steers. In Exp. 1, the bacterial DNA density was greatest for Ruminococcus flavefaciens, Streptococcus bovis, a...

  11. Effect of prior grazing experiences on grazing behavior and performance of lactating cows

    USDA-ARS?s Scientific Manuscript database

    The impact of grazing experiences early in life on grazing behavior and performance of lactating dairy heifers was evaluated in a 3-year study. Sixty-four Holstein and Holstein x Jersey calves were randomly assigned to one of 4 treatments (n = 16) in 2008. Treatments were combinations of managing he...

  12. Water quality and the grazing animal.

    PubMed

    Hubbard, R K; Newton, G L; Hill, G M

    2004-01-01

    Grazing animals and pasture production can affect water quality both positively and negatively. Good management practices for forage production protect the soil surface from erosion compared with conventionally produced crops. Grazing animals and pasture production can negatively affect water quality through erosion and sediment transport into surface waters, through nutrients from urine and feces dropped by the animals and fertility practices associated with production of high-quality pasture, and through pathogens from the wastes. Erosion and sediment transport is primarily associated with high-density stocking and/or poor forage stands. The two nutrients of primary concern relating to animal production are N and P. Nitrogen is of concern because high concentrations in drinking water in the NO(3) form cause methemoglobinemia (blue baby disease), whereas other forms of N (primarily nitrite, NO(2)) are considered to be potentially carcinogenic. Phosphorus in the PO(4) form is of concern because it causes eutrophication of surface water bodies. The effect of grazing animals on soil and water quality must be evaluated at both the field and watershed scales. Such evaluation must account for both direct input of animal wastes from the grazing animal and also applications of inorganic fertilizers to produce quality pastures. Watershed-scale studies have primarily used the approach of nutrient loadings per land area and nutrient removals as livestock harvests. A number of studies have measured nutrient loads in surface runoff from grazed land and compared loads with other land uses, including row crop agriculture and forestry. Concentrations in discharge have been regressed against standard grazing animal units per land area. Watersheds with concentrated livestock populations have been shown to discharge as much as 5 to 10 times more nutrients than watersheds in cropland or forestry. The other major water quality concern with grazing animals is pathogens, which may move

  13. Influence of grazing management on claw disorders in Swedish freestall dairies with mandatory grazing.

    PubMed

    Bergsten, C; Carlsson, J; Jansson Mörk, M

    2015-09-01

    Our hypothesis was that grazing time, the number of days (duration) and number of hours per day, affected claw health. From Swedish freestall herds that fulfilled our criteria of claw-trimming routines, 201 herds were randomly selected for a telephone interview regarding grazing management. Herd data were retrieved from the Swedish Official Milk Recording Scheme. Claw disorders to be analyzed were recorded at maintenance claw trimming before and after the grazing period and included mild and severe dermatitis, severe heel-horn erosion, and sole ulcer (including severe sole hemorrhage). Any remark included one or more of these recorded disorders. The odds for having a recorded claw disorder at the autumn trimming in relation to grazing management, as well as to herd- and cow-related parameters, was tested using multilevel logistic regression models. The final statistical analysis included 17,600 cows in 174 herds, which were distributed from the south to the north of Sweden with decreasing length of mandatory grazing period because of climate. Grazing duration was statistically associated with the risk of sole ulcer, but it was not linear. However, grazing duration was not statistically associated with the odds for any remark, dermatitis, or heel-horn erosion. The odds for dermatitis were lower with access to pasture for 24 h compared with either day or night access. Otherwise, the number of hours that the animals had access to grazing per day was not significantly associated with any of the other analyzed claw disorders. Higher pasture stocking density (number of cow hours per day per hectare) was associated with a higher odds for dermatitis and sole ulcer. For all recorded claw disorders, the highest odds for having a disorder after the grazing period were consistently when the cow had the same claw disorder before the release to pasture. The positive effects of grazing on claw health were less than expected, and the previous known effects of breed, days in milk

  14. Biogenic production of dimethyl sulfide: Krill grazing

    SciTech Connect

    Daly, K.L.; DiTullio, G.R. )

    1993-01-01

    Dimethyl sulfide (DMS), a dominant sulfur compound in sea water, is a possible precursor for cloud condensation nuclei in the atmosphere and may influence global climate. The primary source of DMS is phytoplankton, but the mechanisms remain uncertain, and concentrations of DMS in the ocean vary spatially and temporally. Laboratory studies suggest zooplankton grazing may be an important process leading to the formation of DMS in the ocean. This paper describes ocean studies which examine the suggestion that grazing by krill may be a significant source for DMS production in the antarctic coastal region. 11 refs., 2 figs.

  15. Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

    NASA Astrophysics Data System (ADS)

    Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

    2014-05-01

    Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

  16. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  17. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  18. 76 FR 31977 - Notice of Intent To Prepare an Environmental Impact Statement for Domestic Sheep Grazing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... Sheep Grazing Allotments for Term Grazing Permit Renewals in the Southern San Luis Valley, CO AGENCY... sheep grazing permits on 12 allotments and 1 cattle grazing allotment in the southern San Luis Valley.... SUPPLEMENTARY INFORMATION: Term permits on 12 sheep grazing and 1 cattle grazing allotments located in...

  19. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is grazing capacity determined? 166.305 Section 166.305 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or...

  20. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  1. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  2. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  3. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... rental rate that is less or more than the grazing rental rate established by us. We will assist a tribe... under paragraph (a) of this section. (c) Indian landowners may give us written authority to grant... grazing rental rate set by us; or (2) Below the grazing rental rate set by us, subject to our...

  4. Managing grazing of riparian areas in the Intermountain Region

    Treesearch

    Warren P. Clary; Bert F. Webster

    1989-01-01

    Concern about livestock grazing in riparian habitats and its effect upon riparian-dependent resources has resulted in numerous controversies about the appropriate management approach. This document provides guidance for grazing of riparian areas in a manner that should reduce both nonpoint source pollution and potential grazing impacts on other riparian-dependent...

  5. 36 CFR 222.4 - Changes in grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing... environmental values when exercising the grazing use authorized by the permit. (7) Modify the terms and conditions of a permit to conform to current situations brought about by changes in law, regulation...

  6. 43 CFR 4200.1 - Authority for grazing privileges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Authority for grazing privileges. 4200.1 Section 4200.1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; LIVESTOCK § 4200.1 Authority for grazing privileges....

  7. Home on the range: might the cattle peacefully graze?

    Treesearch

    Sally. Duncan

    1999-01-01

    Grazing and how it impacts the landscape is a concern for public and private land managers. This issue of "Science Findings" examines the issue of cattle and grazing and provides some background, perspective, and research results on various grazing systems. Researchers Jim McIver, of the Forest Service's Blue Mountains Natural Resources Institute, and...

  8. Dietary selection by domestic grazing ruminants: Current state of knowledge

    USDA-ARS?s Scientific Manuscript database

    Ruminants grazing biodiverse pasture face many choices, including when and where to graze and how much herbage to consume. Scientific research has led to considerable knowledge about some of these choices (e.g. herbage DMI), but other aspects of the complex decision-making process of a grazing rumin...

  9. How Does “Hunger” Level Impact Grazing Behavior?

    USDA-ARS?s Scientific Manuscript database

    Grazing behavior can be influenced through feeding and grazing management decisions. Research at our USDA-ARS lab showed that ruminal fill, or how ‘hungry’ the cow is, can affect grazing behavior. Cows that had less ruminal fill took a bigger bite that was shallow and wide, compared to a ‘full’ cow ...

  10. Tillage requirements for vegetables following winter annual grazing

    USDA-ARS?s Scientific Manuscript database

    In Alabama, over 400,000 ac of winter annuals are grazed prior to planting summer row crops. Previous research indicates that cattle grazed on ryegrass (Lolium multiflorum L.) pastures over the winter months in Alabama can be profitable, but winter grazing creates excessive compaction, which advers...

  11. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... rental rate that is less or more than the grazing rental rate established by us. We will assist a tribe... value of grazing on tribal lands. (b) We will establish the grazing rental rate by determining the fair... under paragraph (a) of this section. (c) Indian landowners may give us written authority to grant...

  12. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... rental rate that is less or more than the grazing rental rate established by us. We will assist a tribe... value of grazing on tribal lands. (b) We will establish the grazing rental rate by determining the fair... under paragraph (a) of this section. (c) Indian landowners may give us written authority to grant...

  13. Estimating influence of stocking regimes on livestock grazing distributions

    Treesearch

    Matthew J. Rinella; Marty Vavra; Bridgett J. Naylor; Jennifer M. Boyd

    2011-01-01

    Livestock often concentrate grazing in particular regions of landscapes while partly or wholly avoiding other regions. Dispersing livestock from the heavily grazed regions is a central challenge in grazing land management. Position data gathered from GPS-collared livestock hold potential for increasing knowledge of factors driving livestock aggregation patterns, but...

  14. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who establishes grazing rental rates? 166.400 Section 166.400 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and...

  15. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Who establishes grazing rental rates? 166.400 Section 166.400 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and...

  16. 43 CFR 4110.3 - Changes in grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Changes in grazing preference. 4110.3... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.3 Changes in grazing preference. (a) The authorized officer...

  17. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is grazing capacity determined? 166.305 Section 166.305 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify,...

  18. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  19. Restoring Native California Oaks on Grazed Rangelands

    Treesearch

    Douglas D. McCreary; Jerry Tecklin

    2005-01-01

    Efforts to regenerate oaks on California’s oak woodlands often must address how to establish seedlings in areas grazed by livestock. Research indicates that damage to young oak seedlings from cattle varies by season, with less damage during the winter when deciduous oaks do not have leaves. While exclusion of cattle from planted areas does result in reduced damage, the...

  20. Greenhouse gas exchange over grazed systems

    NASA Astrophysics Data System (ADS)

    Felber, R.; Ammann, C.; Neftel, A.

    2012-04-01

    Grasslands act as sinks and sources of greenhouse gases (GHG) and are, in conjunction with livestock production systems, responsible for a large share of GHG emissions. Whereas ecosystem scale flux measurements (eddy covariance) are commonly used to investigate CO2 exchange (and is becoming state-of-the-art for other GHGs, too), GHG emissions from agricultural animals are usually investigated on the scale of individual animals. Therefore eddy covariance technique has to be tested for combined systems (i.e. grazed systems). Our project investigates the ability of field scale flux measurements to reliably quantify the contribution of grazing dairy cows to the net exchange of CO2 and CH4. To quantify the contribution of the animals to the net flux the position, movement, and grazing/rumination activity of each cow are recorded. In combination with a detailed footprint analysis of the eddy covariance fluxes, the animal related CO2 and CH4 emissions are derived and compared to standard emission values derived from respiration chambers. The aim of the project is to test the assumption whether field scale CO2 flux measurements adequately include the respiration of grazing cows and to identify potential errors in ecosystem Greenhouse gas budgets.

  1. Predicting forage intake in extensive grazing systems

    USDA-ARS?s Scientific Manuscript database

    Voluntary intake by cattle and other ruminants is controlled by a complex mix of physical and physiological factors that interact with a variety of environmental, geo-spatial, and experiential influences external to the animal. These factors are intensified in grazing ruminants, where selective gra...

  2. Pasture quality variation throughout the grazing season

    USDA-ARS?s Scientific Manuscript database

    It is important for dairy producers and their nutritionists to have an idea of the nutritional quality of the pasture they are providing to their cows. This article uses data gathered from several on-going pasture research projects to demonstrate how pasture quality varies during the grazing season,...

  3. 75 FR 29572 - Information Collection; Grazing Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ...] [FR Doc No: 2010-12707] DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLWO220000-L10200000.PH0000.00000000; OMB Control Number 1004-0019] Information Collection; Grazing Management AGENCY: Bureau of Land Management, Interior. ACTION: 30-day Notice and Request for Comments. SUMMARY: The Bureau of...

  4. The Gratifications of Grazing: Why Flippers Flip.

    ERIC Educational Resources Information Center

    Walker, James R.; Bellamy, Robert V., Jr.

    An exploratory study focused on usage patterns of television remote control devices (RCDs), examining how and why individuals use television RCDs to "graze." The study identified the gratifications obtained from RCD use and evaluated their relative importance in accounting for variations in RCD use. Subjects were 455 undergraduates in…

  5. Delineating Grazing: Observations of Remote Control Use.

    ERIC Educational Resources Information Center

    Eastman, Susan Tyler; Newton, Gregory D.

    1995-01-01

    States that contrary to previous reports of "grazing," most viewers only used their remote control devices (RCDs) once or twice every half hour. Claims that the dominant RCD operation was direct channel punching, as opposed to dial turning. Concludes that most RCD activity did not take place during a program, thus voiding industry…

  6. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... permittee who has five or more horses on his current permit will be required to apply any acquired sheep... shall be authorized to graze more than ten head of horses or to accumulate a total of over 350 sheep... permitted holdings of any individual permittee shall not exceed 350 sheep units or the equivalent...

  7. Chapter 2: Livestock and Grazed Lands Emissions

    USDA-ARS?s Scientific Manuscript database

    A total of 342 MMT CO2 eq. of greenhouse gasses (GHGs) were emitted from livestock, managed livestock waste, and grazed land in 2013. This represents about 66% of total emissions from the agricultural sector, which totaled 516 MMT CO2 eq. Compared to the base line year (1990), emissions from livesto...

  8. 50 CFR 35.9 - Livestock grazing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Livestock grazing. 35.9 Section 35.9 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE NATIONAL WILDLIFE REFUGE SYSTEM WILDERNESS PRESERVATION AND MANAGEMENT General Rules § 35.9 Livestock...

  9. Delineating Grazing: Observations of Remote Control Use.

    ERIC Educational Resources Information Center

    Eastman, Susan Tyler; Newton, Gregory D.

    1995-01-01

    States that contrary to previous reports of "grazing," most viewers only used their remote control devices (RCDs) once or twice every half hour. Claims that the dominant RCD operation was direct channel punching, as opposed to dial turning. Concludes that most RCD activity did not take place during a program, thus voiding industry…

  10. The Gratifications of Grazing: Why Flippers Flip.

    ERIC Educational Resources Information Center

    Walker, James R.; Bellamy, Robert V., Jr.

    An exploratory study focused on usage patterns of television remote control devices (RCDs), examining how and why individuals use television RCDs to "graze." The study identified the gratifications obtained from RCD use and evaluated their relative importance in accounting for variations in RCD use. Subjects were 455 undergraduates in…

  11. Public land grazing for private land conservation?

    Treesearch

    Adriana Sulak; Lynn Huntsinger; Sheila Barry; Larry Forero

    2008-01-01

    California ranchers with substantial private oak woodlands sometimes use public lands as an important component of their production cycle. Yet allowed public grazing has declined and is likely to continue to decline. This, combined with intensifying development pressure and land use change, dramatically affects the resource base for ranch operations, which in turn...

  12. Woodlands Grazing Issues in Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Campos, P.

    2009-04-01

    In Mediterranean basin, woodlands grazing still continue to be important commercial owners' benefits. These owners manage woodlands vegetations as if they were not at risk of degradation and declining. Frequently, no temporally grazing set-aside is taken into account to avoid overgrazing of annual and perennial vegetations. Although less common, in the northern shore of Mediterranean basin undergrazing might increase the frequency and the number of catastrophic forest fires. This under/over grazing regime occurs in the Mediterranean basin woodlands with contrasted differences on land property rights, local economies and government livestock policy incentives. Spain and Tunisia are examples of these Mediterranean livestock contrasts. Most of Spanish Mediterranean woodlands and livestock herds are large private ownerships and owners could maintain their lands and livestock herds properties on the basis of moderate cash-income compensation against land revaluation and exclusive amenity self-consumption. The later is less tangible benefit and it could include family land legacy, nature enjoyment, country stile of life development, social status and so on. In public woodlands, social and environmental goals -as they are cultural heritage, biodiversity loss mitigation, soil conservation and employment- could maintain market unprofitable woodlands operations. Last three decades Spanish Mediterranean woodlands owners have increased the livestock herds incentivized by government subsidies. As result, grazing rent is pending on the level of European Union and Spanish government livestock subsidies. In this context, Spanish Mediterranean woodlands maintain a high extensive livestock stoking population, which economy could be called fragile and environmentally unsustainable because forest degradation and over/under grazing practices. Tunisian Mediterranean woodlands are state properties and livestock grazing is practice as a free private regimen. Livestock herds are small herd

  13. Bivalve grazing can shape phytoplankton communities

    USGS Publications Warehouse

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  14. Grazing livestock are exposed to terrestrial cyanobacteria.

    PubMed

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-02-25

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.

  15. Ammonia emissions of a rotational grazing system

    NASA Astrophysics Data System (ADS)

    Voglmeier, Karl; Häni, Christoph; Jocher, Markus; Ammann, Christof

    2017-04-01

    Intensive agricultural livestock production is the main source of air pollution by ammonia (NH3). Grazing is considered to reduce emissions significantly. However, ammonia emissions measurements on pastures are very rare and most emission models base their emissions factors for grazing on studies from the 1990s, which report a large emission range from 2.7% to 13.6% of the applied total ammonia nitrogen (TAN). We present first results of the Posieux pasture experiment in 2016 where NH3 concentration and fluxes were measured during the grazing season. The applied methods include an eddy covariance system with a two channel reactive nitrogen (Nr) converter measuring in parallel the sum of oxidized Nr species and the sum of the total Nr species. The difference of the two channels corresponds to the sum of reduced Nr species. Furthermore four MiniDOAS instruments for line integrated concentration measurements without an inlet system were used. The fluxes were estimated by applying a backward Lagrangian stochastic model (bLS) to the concentration difference of paired MiniDOAS up- and downwind of a sub-plot of the field. Monitoring of dung (visual survey) and urine patch locations (with soil electrical conductivity sensor) was carried out after each grazing rotation on selected sub-plots. It helped to compute statistics of the dung/urine patch distribution on the pasture. The experimental setup and the environmental conditions resulted in high temporal and spatial dynamics of NH3 concentrations and fluxes. The calculated fluxes were used to estimate the total net emission during the grazing period. Based on the average dung/urine patch distribution on the field an emission factor for the pasture was computed and compared to results from the literature. We discuss the applicability and limitations of the two measurement systems, reconsider the main emission drivers and explain differences in the results.

  16. Response of mountain meadows to grazing by recreational pack stock

    USGS Publications Warehouse

    Cole, David N.; Van Wagtendonk, Jan W.; McClaran, Mitchel P.; Moore, Peggy E.; McDougald, Neil K.

    2004-01-01

    Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules grazed experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, grazing caused decreases in productivity. The mean reduction after 4 years of grazing was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. Grazing also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in grazing intensity. Passive management of grazing is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the grazing intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of grazing impact than species composition. Managers must make decisions about maximum acceptable levels of grazing impact and then develop guidelines for maximum use levels, based on data such as ours that relates grazing intensity to meadow response.

  17. Quantification of uncertainties in global grazing systems assessment

    NASA Astrophysics Data System (ADS)

    Fetzel, T.; Havlik, P.; Herrero, M.; Kaplan, J. O.; Kastner, T.; Kroisleitner, C.; Rolinski, S.; Searchinger, T.; Van Bodegom, P. M.; Wirsenius, S.; Erb, K.-H.

    2017-07-01

    Livestock systems play a key role in global sustainability challenges like food security and climate change, yet many unknowns and large uncertainties prevail. We present a systematic, spatially explicit assessment of uncertainties related to grazing intensity (GI), a key metric for assessing ecological impacts of grazing, by combining existing data sets on (a) grazing feed intake, (b) the spatial distribution of livestock, (c) the extent of grazing land, and (d) its net primary productivity (NPP). An analysis of the resulting 96 maps implies that on average 15% of the grazing land NPP is consumed by livestock. GI is low in most of the world's grazing lands, but hotspots of very high GI prevail in 1% of the total grazing area. The agreement between GI maps is good on one fifth of the world's grazing area, while on the remainder, it is low to very low. Largest uncertainties are found in global drylands and where grazing land bears trees (e.g., the Amazon basin or the Taiga belt). In some regions like India or Western Europe, massive uncertainties even result in GI > 100% estimates. Our sensitivity analysis indicates that the input data for NPP, animal distribution, and grazing area contribute about equally to the total variability in GI maps, while grazing feed intake is a less critical variable. We argue that a general improvement in quality of the available global level data sets is a precondition for improving the understanding of the role of livestock systems in the context of global environmental change or food security.

  18. Montane Meadow Plant Community Response to Livestock Grazing

    NASA Astrophysics Data System (ADS)

    Freitas, Matthew R.; Roche, Leslie M.; Weixelman, Dave; Tate, Kenneth W.

    2014-08-01

    We examined long-term (10 years) meadow plant community responses to (1) livestock grazing under riparian grazing utilization limits; (2) suspension of livestock grazing; and (3) meadow site wetness and precipitation on the Inyo National Forest, California. Observed trends in meadow plant species richness, diversity, and frequency of soil stabilizing species were not significantly different between grazed ( N = 16) and non-grazed ( N = 9) study sites ( P > 0.12 in all cases). Modest increases in richness and diversity were observed over the study period, but frequency of soil stabilizing species was constant. These results suggest that riparian conservation grazing strategies implemented during the study period neither degraded nor hampered recovery of meadow plant community conditions relative to non-grazed conditions. Meadow site wetness was negatively correlated to richness ( P < 0.01) and diversity ( P < 0.01), but was positively correlated to soil stabilization ( P = 0.02). Precipitation was not a significant predictor for plant community responses.

  19. Kinetics of lossy grazing impact oscillators

    NASA Astrophysics Data System (ADS)

    Hunt, Jeffery P.; Sarid, Dror

    1998-06-01

    The equation of motion of a grazing impact oscillator is generalized to include compliant boundaries and impact energy dissipation, yielding the phase diagram, indentation and force. Good agreement with experimental results using tapping-mode atomic force microscopy is demonstrated. The relationship between phase and set-point amplitude is discussed in terms of the dissipation, showing that for a parameter space for which the system is highly nonlinear a chaotic response is possible.

  20. Neutron Reflectivity and Grazing Angle Diffraction

    PubMed Central

    Ankner, J. F.; Majkrzak, C. F.; Satija, S. K.

    1993-01-01

    Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and grazing-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the characterization of magnetic, superconducting, and polymeric surfaces and interfaces are included. PMID:28053457

  1. Seasonality constraints to livestock grazing intensity.

    PubMed

    Fetzel, Tamara; Havlik, Petr; Herrero, Mario; Erb, Karl-Heinz

    2017-04-01

    Increasing food production is essential to meet the future food demand of a growing world population. In light of pressing sustainability challenges such as climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock grazing, in particular grazing intensity, an essential variable to assess the sustainability of livestock systems. Here, we explore ecological limits to grazing intensity (GI; i.e. the fraction of net primary production consumed by grazing animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly net primary production data and a map of global livestock distribution with assumptions on the length of nonfavourable periods that can be bridged by livestock (e.g. by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality-limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4% or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio-ecological constraints can be overcome. We discuss socio-ecological trade-offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system's role in the Earth system.

  2. The Effect of Different Type of Herbivores, Grazing Types and Grazing Intensities on Alpine Basiphillous Vegetation of the Romanian Carpathians

    NASA Astrophysics Data System (ADS)

    Ballová, Zuzana; Pekárik, Ladislav; Šibík, Jozef

    2017-04-01

    The major purpose of the present study was to test the hypothesis that there are significant differences in vegetation structure, plant species composition, and soil chemical properties in relation to type of grazing animals, various levels of grazing intensity and grazing type, and if potential differences alter with ecosystem productivity (increase in more productive ecosystems). The study was conducted in three mountain ranges of the Romanian Carpathians with a predominance of alkaline substrates (the Bucegi Mts, the Little Retezat Mts and the Ceahlău Massif). Statistical analyses were performed in R statistical software environment. The effects of grazing animals (cattle, horses and sheep), grazing types (fence, regular, irregular) and grazing intensity (low, medium, high) on the community structure were tested using ordination methods. In the case of soil properties, General Linear Mixed Model was applied. Special statistical approach eliminated the differences between the examined mountains and sites. Type of grazing animal does not significantly influence species cover but it is related to specific species occurrence. According to our results, grazing horses had similar effects as cattle compared to sheep. Grazing in restricted areas (surrounded by fence) and regular unrestricted grazing were more similar if compared to irregular grazing. When comparing the intensity of grazing, high and medium intensity were more similar to each other than to the low intensity grazing. Cattle grazed sites had significantly higher lichens cover, while the sheep patches were covered with increased overall herb layer (forbs, graminoids and low shrubs together). Medium grazing intensity decreased the lichens cover, cover of overall herb layer, and total vegetation cover compared to high and low grazing intensity. Grazing type had important impact on the lichens cover and cover of overall herb layer. The lichens cover appeared to decrease while the cover of overall herb layer

  3. Coma Chemistry of Sun-grazing Comets

    NASA Astrophysics Data System (ADS)

    Charnley, Steven B.; Cordiner, Martin A.; Milam, Stefanie N.; Gicquel, Adeline

    2014-11-01

    The recent apparition of comet C/2012 S1 (ISON), and its disruption during perihelion passage, has motivated numerous observations of the associated variations in the gas and dust composition. More generally, comet ISON has regenerated interest in the physics and chemistry of Sun-grazing comets. Chemical models of cometary comae have typically always been developed to model comets at about 1 AU and beyond [1]. Apart from one early coma chemistry model [2], which calculated the coma chemistry of a comet at 0.125 AU with assumed single-fluid physics, there have been no detailed studies of coma chemistry at the small heliocentric distances experienced by comet ISON and other Sun-grazing comets.In this contribution we will discuss the various physical and chemical processes that have to be considered when modeling the comae of Sun-grazing comets. We will present comet models in which the physical and chemical structures of the multi-fluid flow are calculated self-consistently [3] as a function of decreasing heliocentric distance.[1] Rodgers, S.D., Charnley S.B., Boice, D.C. & Huebner, W.F. (2004) In COMETS II, Eds. Festou, M., Keller, H.U. & Weaver, H.A., University of Arizona Press, 505-522 [2] Swift, M.B. & Mitchell, G.F. (1978) Icarus, 47, 412 [3] Rodgers, S.D. & Charnley, S.B. (2002) MNRAS, 330, 660This work was supported by NASA's Planetary Atmospheres and Planetary Astronomy Programs.

  4. Grazing of heterotrophic dinoflagellate Noctiluca scintillans (Mcartney) Kofoid on Gymnodinium catenatum Graham.

    PubMed

    Alonso Rodríguez, Rosalba; Ochoa, José Luis; Uribe Alcocer, Manuel

    2005-01-01

    A dinoflagellate bloom ("red tide" event) dominated by the toxic Gymnodinium catenatum Graham (Gymnodiniales, Dinophyceae; 99.7%) and the noxious Noctiluca scintillans (Mcartney) Kofoid (Noctilucaceae, Dinophyceae; 0.3%) was observed in Bahia de Mazatlán Bay, México, on 24-26 January 2000. Photographic and microscopic analysis of samples during such an event, allowed us to collect evidence of a marked The particularity of grazing of G. catrenatum by by N. scintillans cells, suggesting a mechanism of "biocontrol" between these species that may contribute to attenuate a potentially toxic phenomenon under natural conditions.

  5. Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.

    PubMed

    Wiking, Lars; Theil, Peter K; Nielsen, Jacob H; Sørensen, Martin T

    2010-08-01

    The impact of fresh legume types or silage on the composition of milk fatty acids and transcription of enzymes involved in the synthesis of milk fat in cows was studied. Three groups of cows grazed high proportions of white clover, red clover and lucerne, respectively. A fourth group of cows was fed maize/grass silage. The cows grazing high proportions of legumes produced significantly more 18:1 trans-11, 18:2 cis9-trans11, 18:2 trans10-cis12 and 18:3 fatty acids than cows fed silage. White clover and lucerne grazing resulted in significantly lower output of 18:1 trans9 in milk than red clover grazing and maize/grass silages. Transcription of stearoyl-CoA desaturase (SCD) in mammary tissue was significantly increased by grazing high proportions of legume whereas fatty acid synthase and acetyl-CoA carboxylase were not affected by type of feeding. Furthermore, average milk fat globule diameter was correlated to daily milk fat yield but was not affected by feeding. Although the fresh forage affected the transcription of SCD in mammary tissue, the largest effects were on the trans11-based fatty acids. It is concluded that type of forage, i.e. fresh or silage, had a greater impact on rumen fermentation pattern than on transcription of enzymes involved in the synthesis of milk fat.

  6. Growth phase and elemental stoichiometry of bacterial prey influences ciliate grazing selectivity.

    PubMed

    Gruber, David F; Tuorto, Steven; Taghon, Gary L

    2009-01-01

    Protozoa are known to selectively graze bacteria and can differentiate prey based on size and viability, but less is known about the effects of prey cellular composition on predator selectivity. We measured the effect of growth phase and elemental stoichiometry of Escherichia coli on grazing by two ciliates, Euplotes vannus and Cyclidium glaucoma. Bacterial cells of a single strain were transformed with green and red fluorescent protein and harvested from culture at differing growth stages. Cells in exponential growth phase had low carbon:phosphorus (39) and nitrogen:phosphorus (9) ratios, while cells from stationary phase had high carbon:phosphorus of 104 and nitrogen:phosphorus of 26. When offered an equal mixture of both types of bacteria, Cyclidium grazed stationary phase, high carbon:phosphorus, high nitrogen:phosphorus cells to 22% of initial abundance within 135 min, while Euplotes reduced these cells to 33%. Neither ciliate species decreased the abundance of the exponential phase cells, lower carbon:phosphorus and nitrogen:phosphorus, relative to control treatments. Because protozoa have higher nitrogen:phosphorus and carbon:phosphorus ratios than their prokaryotic prey, this study raises the possibility that it may be advantageous for protozoa to preferentially consume more slowly growing bacteria.

  7. Effect of Restricted Grazing Time on the Foraging Behavior and Movement of Tan Sheep Grazed on Desert Steppe

    PubMed Central

    Chen, Yong; Luo, Hailing; Liu, Xueliang; Wang, Zhenzhen; Zhang, Yuwei; Liu, Kun; Jiao, Lijuan; Chang, Yanfei; Zuo, Zhaoyun

    2013-01-01

    To investigate the effect of restricted grazing time on behavior of Tan sheep on desert steppe, forty 4-months old male Tan sheep with an original body weight (BW) of 15.62±0.33 kg were randomly allocated to 4 grazing groups which corresponded to 4 different restricted grazing time treatments of 2 h/d (G2), 4 h/d (G4), 8 h/d (G8) and 12 h/d (G12) access to pasture. The restricted grazing times had a significant impact on intake time, resting time, ruminating time, bite rate and movement. As the grazing time decreased, the proportion of time spent on intake, bite rate and grazing velocity significantly (p<0.05) increased, but resting and ruminating time clearly (p<0.05) decreased. The grazing months mainly depicted effect on intake time and grazing velocity. In conclusion, by varying their foraging behavior, Tan sheep could improve grazing efficiency to adapt well to the time-limited grazing circumstance. PMID:25049843

  8. Carbon budgets for an irrigated intensively grazed dairy pasture and an unirrigated winter-grazed pasture

    NASA Astrophysics Data System (ADS)

    Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.

    2016-05-01

    Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by grazing cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.

  9. Growth of a grazing phytoplanktivorous fish and growth enhancement of the grazed alga.

    PubMed

    McDonald, Michael E

    1985-08-01

    The blue tilapia, Tilapia aurea, consumes the green alga, Ankistrodesmus falcatus, with some algal cells passing through the gut in viable condition. Grazing fish grew and the grazed algal populations had enhanced densities compared to ungrazed populations. Algal growth enhancement was not produced by either bacteria or fish excreting an algal limiting nutrient. Possible ingestion and digestion of bacterial cells by the fish might release nutrients to the algal cells that were otherwise unavailable. Blue tilapia may be affecting algal communities in ways other than by passive size selection. Enhancement of algal growth by the blue tilapia could have important implications for understanding the phytoplankton dynamics in waters containing blue tilapia.

  10. Peracute vanadium toxicity in cattle grazing near a vanadium mine.

    PubMed

    McCrindle, C M; Mokantla, E; Duncan, N

    2001-12-01

    Animals may act as bioindicators for potential human health problems associated with mining and refining. Eight cattle died after a vanadium mine dam collapsed close to the area in which they were grazing. Necropsies were conducted on five cattle. Affected animals had shown a watery bloody diarrhea, red urine and listlessness before collapsing. On necropsy (n = 5) there was a moderate bilateral multifocal granulomatous-like conjunctivitis. The most prominent lesions were eosinophillic granulomatous-like inflammation of the thymus, mediastinal and mesenteric lymph nodes, oesophagus, abomasum and colon. There was also marked hyperaemia of the abomasal mucosa with petechiation. Pulmonary and tracheal haemorrhage was also present. Histopathology showed severe inflammatory cell infiltration (mainly eosinophils with lesser numbers of neutrophils and macrophages) of lymphoid tissue associated with the thymus, lymph nodes, esophagus, abomasum, colon and conjunctiva. There were also areas of tissue necrosis, congested blood vessels and haemorrhage. Conjunctival lesions point to a systemic rather than a local effect as the cattle in this case died following ingestion rather than inhalation of vanadium. The causal relationship between intoxication and death is conventionally based on the level of that toxin present in tissues at necropsy. The variability in demonstrating vanadium in biological samples may have been due to the rapid excretion of vanadium by the living animal, or the solubility of the salts, which results in the substance leaching into the fluid portion of the samples. Cross-reactions with colorimetric tests for arsenic should also be noted.

  11. 25 CFR 166.414 - What forms of grazing rental payments are acceptable?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What forms of grazing rental payments are acceptable? 166... GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.414 What forms of grazing rental payments are acceptable? (a) When grazing rental payments are...

  12. 25 CFR 161.400 - What are the criteria for reissuing grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What are the criteria for reissuing grazing permits? 161... PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.400 What are the criteria for reissuing grazing permits? (a) The Navajo Nation may prescribe eligibility requirements for grazing...

  13. 25 CFR 166.414 - What forms of grazing rental payments are acceptable?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What forms of grazing rental payments are acceptable? 166... GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.414 What forms of grazing rental payments are acceptable? (a) When grazing rental payments are...

  14. 25 CFR 161.302 - What restrictions are placed on grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What restrictions are placed on grazing permits? 161.302... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.302 What restrictions are placed on grazing permits? Only a grazing permit issued under this part authorizes the grazing of livestock within...

  15. 25 CFR 161.400 - What are the criteria for reissuing grazing permits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What are the criteria for reissuing grazing permits? 161... PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.400 What are the criteria for reissuing grazing permits? (a) The Navajo Nation may prescribe eligibility requirements for grazing...

  16. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How are grazing permits allocated within each range unit... NAVAJO PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.403 How are grazing permits... grazing permit will be determined by considering the number of animal units previously authorized in...

  17. 43 CFR 4130.6-4 - Special grazing permits or leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Special grazing permits or leases. 4130.6... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-4 Special grazing permits or leases. Special grazing permits...

  18. Red Sky with Red Mesa

    SciTech Connect

    2011-04-14

    The Red Sky/Red Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.

  19. Red Sky with Red Mesa

    ScienceCinema

    None

    2016-07-12

    The Red Sky/Red Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.

  20. Developmental instability and fitness in Periploca laevigata experiencing grazing disturbance

    USGS Publications Warehouse

    Alados, C.L.; Giner, M.L.; Dehesa, L.; Escos, J.; Barroso, F.; Emlen, J.M.; Freeman, D.C.

    2002-01-01

    We investigated the sensitivity of developmental instability measurements (leaf fluctuating asymmetry, floral radial asymmetry, and shoot translational asymmetry) to a long‐standing natural stress (grazing) in a palatable tannin‐producing shrub (Periploca laevigata Aiton). We also assessed the relationship between these measures of developmental instability and fitness components (growth and floral production). Developmental instability, measured by translational asymmetry, was the most accurate estimator of a plant’s condition and, consequently, environmental stress. Plants with less translational asymmetry grew more and produced more flowers. Plants from the medium‐grazed population were developmentally more stable, as estimated by translational and floral asymmetry, than either more heavily or more lightly grazed populations. Leaf fluctuating asymmetry was positively correlated with tannin concentration. The pattern of internode growth also responded to grazing impact. Plants under medium to heavy grazing pressure accelerated early growth and consequently escaped herbivory later in the season, i.e., at the beginning of the spring, when grazing activity was concentrated in herbaceous plants. Periploca laevigata accelerated growth and finished growing sooner than in the other grazing treatment. Thus, its annual growth was more mature and less palatable later in the season when grazers typically concentrate on shrubs. The reduction of developmental instability under medium grazing is interpreted as a direct effect of grazing and not as the release from competition.

  1. Polar stellar-spots and grazing planetary transits. Possible explanation for the low number of discovered grazing planets

    NASA Astrophysics Data System (ADS)

    Oshagh, M.; Santos, N. C.; Figueira, P.; Adibekyan, V. Zh.; Santerne, A.; Barros, S. C. C.; Lima, J. J. G.

    2015-11-01

    We assess whether there is a physically feasible explanation for the few discovered (nearly) grazing planetary transits through all ground- and space-based transit surveys. We performed simulations to generate a synthetic distribution of detectable planets based on their impact parameter, and found that more (nearly) grazing planets should have been detected than have been detected. Our explanation for the insufficient number of (nearly) grazing planets is based on the simple assumption that many (nearly) grazing planets transit host stars that harbor a dark giant polar spot, and thus the transit light-curve vanishes due to the occultation of the grazing planet and the polar spot. We conclude by evaluating the properties required of polar spots to cause the grazing transit light-curve to disappear and find that the spot properties are compatible with the expected properties from observations.

  2. Comparison of bloat potential between a variety of soft-red versus a variety of hard-red winter wheat forage.

    PubMed

    Akins, M S; Kegley, E B; Coffey, K P; Caldwell, J D; Lusby, K S; Moore, J C; Coblentz, W K

    2009-10-01

    Some aspects of wheat pasture bloat have been researched extensively, but few studies have evaluated the effect of wheat type or variety on bloat. Eight Gelbvieh x Angus ruminally cannulated heifers (515 +/- 49 kg of BW) and 48 Angus heifers (238 +/- 12 kg of BW) grazed 1-ha pastures of hard-red or soft-red winter wheat (Triticum aestivum L.) to evaluate the effect of wheat variety on bloat potential. In Exp. 1, cattle grazed from November 11 to 22 and from November 26 to December 7, 2006, in a crossover design. In Exp. 2, cattle were shrunk for 20 h and then grazed from December 19 to 20, 2006, and from January 19 to 20, 2007. In both experiments, bloat was scored at 1000 and 1600 h daily. Rumen samples were collected at 0600, 1200, and 1800 h during each of the last 2 d of each period in Exp. 1 and during both days of each period of Exp. 2. Rumen samples were evaluated for pH, foam production and strength, and viscosity. In Exp. 1, cannulated heifers grazing soft-red had a greater (P < 0.01) percentage of observed bloat (21.9 vs. 5.6%) than those grazing hard-red winter wheat, but bloat incidence was low (2.1%) for the stocker cattle, with no difference between hard-red and soft-red winter wheat (P = 0.52). Viscosity of the rumen fluid was affected (P = 0.03) by the wheat variety x time interaction, with soft-red at 1200 and 1800 h being more viscous than soft-red at 0600 h and hard-red at all times. Foam strength, as determined by bubbling CO(2) gas through rumen fluid, had a wheat variety x time interaction (P = 0.02) with both wheat varieties similar at 0600 h but soft-red having greater foam strength at 1200 and 1800 h. In Exp. 2, no bloat was observed, and no differences between wheat varieties were observed for any of the rumen foam measures. Therefore, for these 2 varieties, the soft-red winter wheat had a greater bloat potential than the hard-red winter wheat based on results from the cannulated heifers, but no differences were observed in the frequency

  3. Forage quality and grazing performance of beef cattle grazing brown mid-rib grain sorghum residue

    USDA-ARS?s Scientific Manuscript database

    Residue from grain sorghum hybrids, one control (AWheatland x RTx430) and its near isogenic with the brown mid-rib (BMR) trait, were compared in a 72-d grazing experiment. Forty eight steers (250 ± 23 kg) were stratified by BW and assigned randomly to 2.12 ha paddocks (6 steers/paddock) containing B...

  4. Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System

    PubMed Central

    Roets, Francois; Samways, Michael J.

    2016-01-01

    Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs. PMID:27783685

  5. SLOPE PROFILOMETRY OF GRAZING INCIDENCE OPTICS.

    SciTech Connect

    TAKACS,P.Z.

    2003-01-14

    Profiling instruments are well-suited to the measurement of grazing incidence optics, such as those found in synchrotron radiation beam lines. Slope measuring profilers, based upon the principle of the pencil beam interferometer, have proven to be especially useful in measuring the figure and slope errors on cylindrical aspheres. The Long Trace Profiler, in various configurations, is the most widely used of this class of profiler. Current performance provides slope measurement accuracy at the microradian level and height measurements accurate to 25 nm over 1 meter trace lengths.

  6. Dietary selection of sheep grazing the semi-arid grasslands of Inner Mongolia, China at different grazing intensities.

    PubMed

    Schiborra, A; Gierus, M; Wan, H W; Glindemann, T; Wang, C J; Susenbeth, A; Taube, F

    2010-08-01

    The objective of this study was to investigate dietary selection of sheep grazing semi-arid grassland in Inner Mongolia, China, using the difference in organic matter digestibility (OMD) of herbage ingested and herbage on offer as indicator for selection. Faecal N was used as digestibility index for herbage ingested (FOMD), while OMD of herbage on offer (GOMD) was estimated from gas production obtained by the Hohenheim gas test. It was hypothesized that the difference between FOMD and GOMD is high, when grazing animals select against low quality herbage provided that herbage is abundant. In a grazing experiment, six grazing intensities (1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ha), representing light to very heavy grazing intensity for the semi-arid grassland, were compared. The amount of herbage on offer decreased with increasing grazing intensity. Independent statistical analysis of FOMD and GOMD showed that the differences between grazing intensities for both OMD determinations (FOMD: 54.0-57.3%, GOMD: 55.2-57.5%) were not significant (p > 0.05). The difference between FOMD and GOMD was not significant for grazing intensities, but varied between sampling periods from -4 to 1 percentage units. In conclusion, the lack of significance for the difference between FOMD and GOMD suggests that for the semi-arid grassland of Inner Mongolia, China, sheep did not select their feed due to a homogeneous nutritional composition of herbage on offer in 2005, regardless of grazing intensity.

  7. Red Hill

    EPA Pesticide Factsheets

    Information about the Red Hill Bulk Fuel Storage Facility in Hawaii Administrative Order on Consent (AOC), an enforceable agreement of the Hawaii Department of Health, the Environmental Protection Agency, and the U.S. Navy -- Defense Logistics Agency.

  8. Grazing Affects Exosomal Circulating MicroRNAs in Cattle

    PubMed Central

    Muroya, Susumu; Ogasawara, Hideki; Hojito, Masayuki

    2015-01-01

    Circulating microRNAs (c-miRNAs) are associated with physiological adaptation to acute and chronic aerobic exercise in humans. To investigate the potential effect of grazing movement on miRNA circulation in cattle, here we profiled miRNA expression in centrifugally prepared exosomes from the plasma of both grazing and housed Japanese Shorthorn cattle. Microarray analysis of the c-miRNAs resulted in detection of a total of 231 bovine exosomal miRNAs in the plasma, with a constant expression level of let-7g across the duration and cattle groups. Expression of muscle-specific miRNAs such as miR-1, miR-133a, miR-206, miR-208a/b, and miR-499 were undetectable, suggesting the mildness of grazing movement as exercise. According to validation by quantitative RT-PCR, the circulating miR-150 level in the grazing cattle normalized by the endogenous let-7g level was down-regulated after 2 and 4 months of grazing (P < 0.05), and then its levels in housed and grazing cattle equalized when the grazing cattle were returned to a housed situation. Likewise, the levels of miR-19b, miR-148a, miR-221, miR-223, miR-320a, miR-361, and miR-486 were temporarily lowered in the cattle at 1 and/or 2 month of grazing compared to those of the housed cattle (P < 0.05). In contrast, the miR-451 level was up-regulated in the grazing cattle at 2 months of grazing (P = 0.044). The elevation of miR-451 level in the plasma was coincident with that in the biceps femoris muscle of the grazing cattle (P = 0.008), which suggests the secretion or intake of miR-451 between skeletal muscle cells and circulation during grazing. These results revealed that exosomal c-miRNAs in cattle were affected by grazing, suggesting their usefulness as molecular grazing markers and functions in physiological adaptation of grazing cattle associated with endocytosis, focal adhesion, axon guidance, and a variety of intracellular signaling, as predicted by bioinformatic analysis. PMID:26308447

  9. The current status of red spruce in the eastern United States: distribution, population trends, and environmental drivers

    Treesearch

    Gregory Nowacki; Robert Carr; Michael. Van Dyck

    2010-01-01

    Red spruce (Picea rubens Sarg.) was affected by an array of direct (logging, fire, and grazing) and indirect human activities (acid deposition) over the past centuries. To adequately assess past impacts on red spruce, thus helping frame its restoration potential, requires a clear understanding of its current status. To achieve this, Forest and...

  10. Dugong grazing and turtle cropping: grazing optimization in tropical seagrass systems?

    PubMed

    Aragones, Lemnuel V; Lawler, Ivan R; Foley, William J; Marsh, Helene

    2006-10-01

    Grazing by dugongs and cropping by green turtles have the capacity to alter the subsequent nutritional quality of seagrass regrowth. We examined the effects of simulated light and intensive grazing by dugongs and cropping by turtles on eight nutritionally relevant measures of seagrass chemical composition over two regrowth periods (short-term, 1-4 months; long-term, 11-13 months) at two seagrass communities (a mixed species community with Zostera capricorni, Halophila ovalis, Halodule uninervis, Cymodocea rotundata and C. serrulate; and a monospecific bed of Halodule uninervis) in tropical Queensland, Australia. The concentrations of organic matter, total nitrogen, total water-soluble carbohydrates, total starch, neutral detergent fiber, acid detergent fiber, acid lignin, as well as the in vitro dry matter digestibility (IVDMD) were measured in the leaves and below-ground parts of each species using near-infrared reflectance spectroscopy (NIRS). Regrowth of preferred species such as H. ovalis and H. uninervis from simulated intensive dugong grazing after a year exhibited increased (by 35 and 25%, respectively, relative to controls) whole-plant N concentrations. Similarly, regrowth of H. ovalis from simulated turtle cropping showed an increase in the leaf N concentration of 30% after a year. However, these gains are tempered by reductions in starch concentrations and increases in fiber. In the short-term, the N concentrations increased while the fiber concentrations decreased. These data provide experimental support for a grazing optimization view of herbivory in the tropical seagrass system, but with feedback in a different manner. Furthermore, we suggest that in areas where grazing is the only major source of natural disturbance, it is likely that there are potential ecosystem level effects if and when numbers of dugongs and turtles are reduced.

  11. Nitrous oxide and greenhouse gas emissions from grazed pastures as affected by use of nitrification inhibitor and restricted grazing regime.

    PubMed

    Luo, Jiafa; Ledgard, Stewart F; Lindsey, Stuart B

    2013-11-01

    Integration of a restricted grazing regime in winter with the use of a nitrification inhibitor can potentially reduce N2O emissions from grazed pasture systems. A three year field study was conducted to compare annual N2O emission rates from a "tight nitrogen" grazed farmlet with those from a control farmlet. The control farmlet was managed under a conventional rotational all-year grazing regime, while the "tight nitrogen" farmlet was under a similar grazing regime, except during winter and early spring seasons when cows grazed for about 6h per day. A nitrification inhibitor (dicyandiamide, DCD) was applied onto the "tight nitrogen" farmlet immediately after grazing through winter and early spring. A chamber technique was used to measure N2O emissions in several paddocks from each farmlet during three contrasting seasons each year. The IPCC (Intergovernmental Panel on Climate Change) inventory methodology was used to estimate CH4 and indirect N2O emissions and the life cycle assessment (LCA) methodology was used to calculate CO2 emissions from the farm systems. The individual and combined effects of restricted grazing and DCD use on N2O emissions were also determined. During the late spring/summer and autumn periods, N2O emission rates were generally similar between the two farmlets. The use of a restricted grazing regime and DCD reduced N2O emissions from the grazed farmlet during the winter/early spring seasons by 43-55%, 64-79% and 45-60% over each of the three years, respectively. The use of restricted grazing and DCD both resulted in a similar reduction in N2O emissions, but there was no significant further reduction from the combination of these technologies. For the three study years, the annual N2O emission rate from the "tight nitrogen" farmlet was 20% lower, on average, than from the control. Total annual greenhouse gas (GHG) emissions, however, were only 5% less in the "tight nitrogen" system.

  12. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... (ii) The board becomes inactive and does not meet at least once each calendar year. (86 Stat. 770 (5 U... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Grazing advisory boards. 222... maintain at least one grazing advisory board. (2) The Chief, Forest Service, shall determine the number of...

  13. Pasture growth and decomposition under continuous and rotational grazing

    USDA-ARS?s Scientific Manuscript database

    Past research has shown that grazing management can affect both pasture growth and litter decomposition. The objective of this study was to compare forage appearance (growth) and forage disappearance (decomposition) on both continuous and rotational grazed beef cattle pasture in Ohio. Data was colle...

  14. Dairy farmers using mob grazing in Pennsylvania and New York

    USDA-ARS?s Scientific Manuscript database

    Proponents of ultra-high stocking density grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 500,000 lb per acre of beef cattle on small paddocks with rest periods up to 180 days. However, it is unclear if this management tec...

  15. A look at dairy mob grazing in the Northeast

    USDA-ARS?s Scientific Manuscript database

    Proponents of ultra-high stocking density (UHSD) grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 kg/ha of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management te...

  16. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Grazing of livestock. 293.7 Section 293.7 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE WILDERNESS... National Forests and in accordance with special provisions covering grazing use in units of National...

  17. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Grazing of livestock. 293.7 Section 293.7 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE WILDERNESS... National Forests and in accordance with special provisions covering grazing use in units of National...

  18. Economic viability of beef cattle grazing systems under prolonged drought

    USDA-ARS?s Scientific Manuscript database

    Prolonged drought in the Southern Great Plains of the USA in recent years has raised concerns about vulnerability of beef cattle grazing systems under adverse climate change. To help address the economic viability of beef grazing operations in the Southern Great Plains, this paper provides an econom...

  19. Consequences of ignoring geologic variation in evaluating grazing impacts

    Treesearch

    Jonathan W. Long; Alvin L. Medina

    2006-01-01

    The geologic diversity of landforms in the Southwest complicates efforts to evaluate impacts of land uses such as livestock grazing. We examined a research study that evaluated relationships between trout biomass and stream habitat in the White Mountains of east-central Arizona. That study interpreted results of stepwise regressions and a nonparametric test of “grazed...

  20. From the lab bench: A systematic approach to grazing cattle

    USDA-ARS?s Scientific Manuscript database

    A column was written to discuss the use of grazing systems to overcome challenges of managing grazed pastures. Kentucky cattlemen must manage around summer slumps in growth of cool-season perennial grasses, periodic drought, and cattle markets that do not always cooperate with pasture growth patter...

  1. Targeted grazing: Applying the research to the land

    USDA-ARS?s Scientific Manuscript database

    The discipline of range science is in part based on the observation that vegetation on rangelands changes in response to livestock grazing. For much of the history of range science, livestock grazing was considered to affect range plants and ecological condition negatively. Thus range plants were cl...

  2. Grazing effects on carbon fluxes in a northern China grassland

    USDA-ARS?s Scientific Manuscript database

    Grazing is a widespread use of grasslands in northern China, but if stocking rate exceeds grassland carrying capacity, degradation and desertification can occur. As a result, grazing management is critical and can play a significant role in driving C sink and source activity in grassland ecosystems...

  3. Cattle grazing and vegetation succession on burned sagebrush steppe

    USDA-ARS?s Scientific Manuscript database

    There is limited information on the effects of cattle grazing to longer-term plant community composition and productivity following fire in big sagebrush steppe. This study evaluated vegetation response to cattle grazing over seven years (2007-2013) on burned Wyoming big sagebrush (Artemisia triden...

  4. Grazing Intensity Does Not Affect Plant Diversity in Shortgrass Steppe

    USDA-ARS?s Scientific Manuscript database

    Responses of livestock gain and forage production to grazing intensity in shortgrass steppe are well-established, but effects on basal cover and plant diversity are less so. A long-term grazing intensity study was initiated on shortgrass steppe at the Central Plains Experimental Range (USDA-Agricult...

  5. Using packrat middens to assess grazing effects on vegetation change

    USGS Publications Warehouse

    Fisher, J.; Cole, K.L.; Anderson, R. Scott

    2009-01-01

    Research on grazing effects usually compares the same sites through time or grazed and ungrazed sites over the same time period. Both approaches are complicated in arid environments where grazing can have a long undocumented history and landscapes can be spatially heterogenous. This work employs both approaches simultaneously by comparing grazed and ungrazed samples through both time and space using fossil plant macrofossils and pollen from packrat middens. A series of 27 middens, spanning from 995 yr BP to the present, were collected from Glen Canyon in southeastern Utah, USA. These middens detail vegetation change just prior to, and following, the historical introduction of domesticated grazers and also compares assemblages from nearby ungrazable mesas. Pre-grazing middens, and modern middens from ungrazed areas, record more native grasses, native herbs, and native shrubs such as Rhus trilobata, Amelanchier utahensis, and Shepherdia rotundifolia than modern middens from grazed areas. Ordinations demonstrate that site-to-site variability is more important than any temporal changes, making selection of comparable grazed versus ungrazed study treatments difficult. But within similar sites, the changes through time show that grazing lowered the number of taxa recorded, and lessened the pre-existing site differences, homogenizing the resultant plant associations in this desert grassland.

  6. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... recommendations concerning the development of allotment management plans and the utilization of range betterment....11 Section 222.11 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.11 Grazing advisory boards. (a...

  7. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... recommendations concerning the development of allotment management plans and the utilization of range betterment....11 Section 222.11 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.11 Grazing advisory boards. (a...

  8. 36 CFR 222.4 - Changes in grazing permits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing... permit back to the United States. (iv) Fails to restock the allotted range after full extent of approved..., executive order, development or revision of an allotment management plan, or other management needs. (8...

  9. Estimating influence of stocking regimes on livestock grazing distributions

    USDA-ARS?s Scientific Manuscript database

    Ungulates often concentrate grazing at small hotspots in the larger landscape, and dispersing livestock away from these intensively grazed areas is one of the central challenges in range management. We evaluated a technique based on shifting the stocking date to prevent overgrazing of small areas co...

  10. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... recommendations concerning the development of allotment management plans and the utilization of range betterment....11 Section 222.11 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.11 Grazing advisory boards. (a...

  11. 36 CFR 222.4 - Changes in grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing... permit back to the United States. (iv) Fails to restock the allotted range after full extent of approved..., executive order, development or revision of an allotment management plan, or other management needs. (8...

  12. 36 CFR 222.4 - Changes in grazing permits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing... permit back to the United States. (iv) Fails to restock the allotted range after full extent of approved..., executive order, development or revision of an allotment management plan, or other management needs. (8...

  13. Using dual-purpose crops in sheep-grazing systems.

    PubMed

    Dove, Hugh; Kirkegaard, John

    2014-05-01

    The utilisation of dual-purpose crops, especially wheat and canola grown for forage and grain production in sheep-grazing systems, is reviewed. When sown early and grazed in winter before stem elongation, later-maturing wheat and canola crops can be grazed with little impact on grain yield. Recent research has sought to develop crop- and grazing-management strategies for dual-purpose crops. Aspects examined have been grazing effects on crop growth, recovery and yield development along with an understanding of the grazing value of the crop fodder, its implications for animal nutrition and grazing management to maximise live-weight gain. By alleviating the winter 'feed gap', the increase in winter stocking rate afforded by grazing crops allows crop and livestock production to be increased simultaneously on the same farm. Integration of dual-purpose wheat with canola on mixed farms provides further systems advantages related to widened operational windows, weed and disease control and risk management. Dual-purpose crops are an innovation that has potential to assist in addressing the global food-security challenge.

  14. Targeted livestock grazing to improve and restore rangelands

    USDA-ARS?s Scientific Manuscript database

    Targeted grazing is the application of a specific kind of livestock at the appropriate season, duration, and intensity to accomplish defined vegetation or landscape goals. Grazing by wild and domestic animals is a powerful natural force working in all ecosystems. The ability of selective herbivory t...

  15. Simulated grazing responses on the proposed prairies National Park

    NASA Astrophysics Data System (ADS)

    Parton, William J.; Wright, R. Gerald; Risser, Paul G.

    1980-03-01

    The tallgrass prairie version of the ELM Grassland Model was used to evaluate the potential impact of establishing a tallgrass prairie National Park in the Flint Hills region of Kansas. This total ecosystem model simulates ( a) the flow of water, heat, nitrogen, and phosphorus through the ecosystem and( b) the biomass dynamics of plants and consumers. It was specifically developed to study the effects of levels and types of herbivory, climatic variation, and fertilization upon grassland ecosystems. The model was used to simulate the impact of building up herds of bison, elk, antelope, and wolves on a tallgrass prairie. The results show that the grazing levels in the park should not be decreased below the prepark grazing levels (moderate grazing with cattle) and that the final grazing levels in the park could be maintained at a slightly higher level than the prepark grazing levels.

  16. Mixed Grazing Systems Benefit both Upland Biodiversity and Livestock Production

    PubMed Central

    Fraser, Mariecia D.; Moorby, Jon M.; Vale, James E.; Evans, Darren M.

    2014-01-01

    Background With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21st century, but this has to be achieved in a sustainable way. Livestock grazing management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously. Methods Using a replicated, landscape-scale field experiment consisting of five management ‘systems’ we tested the effects of progressively altering elements within an upland farming system, viz i) incorporating cattle grazing into an upland sheep system, ii) integrating grazing of semi-natural rough grazing into a mixed grazing system based on improved pasture, iii) altering the stocking ratio within a mixed grazing system, and iv) replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years. Results, Conclusion and Significance We found that management systems incorporating mixed grazing with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough grazing consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer grazing of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland grazing systems not only improve livestock production, but also benefit biodiversity

  17. Carbon flux assessment in cow-calf grazing systems.

    PubMed

    Chiavegato, M B; Rowntree, J E; Powers, W J

    2015-08-01

    Greenhouse gas (GHG) fluxes and soil organic carbon (SOC) accumulation in grassland ecosystems are intimately linked to grazing management. This study assessed the carbon equivalent flux (Ceq) from 1) an irrigated, heavily stocked, low-density grazing system, 2) a nonirrigated, lightly stocked, high-density grazing system, and 3) a grazing-exclusion pasture site on the basis of the GHG emissions from pasture soils and enteric methane emissions from cows grazing different pasture treatments. Soil organic carbon and total soil nitrogen stocks were measured but not included in Ceq determination because of study duration and time needed to observe a change in soil composition. Light- and heavy-stocking systems had 36% and 43% greater Ceq than nongrazed pasture sites, respectively ( < 0.01). The largest contributor to increased Ceq from grazing systems was enteric CH emissions, which represented 15% and 32% of the overall emissions for lightly and heavily stocked grazing systems, respectively. Across years, grazing systems also had increased nitrous oxide (N2O; < 0.01) and CH emissions from pasture soils ( < 0.01) compared with nongrazed pasture sites but, overall, minimally contributed to total emissions. Results indicate no clear difference in Ceqflux between the grazing systems studied when SOC change is not incorporated ( = 0.11). A greater stocking rate potentially increased total SOC stock ( = 0.02), the addition of SOC deeper into the soil horizon ( = 0.01), and soil OM content to 30 cm ( < 0.01). The incorporation of long-term annual carbon sequestration into the determination of Ceq could change results and possibly differentiate the grazing systems studied.

  18. Mixed grazing systems benefit both upland biodiversity and livestock production.

    PubMed

    Fraser, Mariecia D; Moorby, Jon M; Vale, James E; Evans, Darren M

    2014-01-01

    With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21(st) century, but this has to be achieved in a sustainable way. Livestock grazing management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously. Using a replicated, landscape-scale field experiment consisting of five management 'systems' we tested the effects of progressively altering elements within an upland farming system, viz i) incorporating cattle grazing into an upland sheep system, ii) integrating grazing of semi-natural rough grazing into a mixed grazing system based on improved pasture, iii) altering the stocking ratio within a mixed grazing system, and iv) replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years. We found that management systems incorporating mixed grazing with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough grazing consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer grazing of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland grazing systems not only improve livestock production, but also benefit biodiversity, suggesting a 'win-win' solution for farmers and conservationists.

  19. Graze eating among bariatric surgery candidates: prevalence and psychosocial correlates.

    PubMed

    Goodpaster, Kasey P S; Marek, Ryan J; Lavery, Megan E; Ashton, Kathleen; Merrell Rish, Julie; Heinberg, Leslie J

    2016-06-01

    Graze eating is defined as repetitive, unplanned eating of small amounts of food throughout the day. Little consensuses exist regarding whether graze eating, like binge eating disorder (BED), is characterized by feelings of loss of control (LOC). Furthermore, little is known about how patients who graze eat with and without LOC differ psychologically. The present study seeks to better characterize graze eating by examining differences between graze eating with LOC (+LOC) and without LOC (-LOC) among presurgical bariatric patients. A large, Midwestern academic medical center. The sample consisted of 288 adult bariatric surgery candidates (mean age 45.8, standard deviation [SD] 12.57) who underwent a presurgical psychological evaluation. Graze eating, BED, and other mental health diagnoses were evaluated using a semistructured interview. Participants were also administered the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and binge eating scale (BES). Data were collected using a retrospective chart review. Among the 33% (n = 95) of the sample who reported preoperative graze eating, 32% (n = 30) also endorsed LOC. Graze eating, particularly with LOC, was associated with Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) diagnoses of anxiety disorders and BED, and multiple measures of internalizing dysfunction on the MMPI-2-RF. Bariatric surgery candidates who graze eat experience a greater degree of overall distress and psychopathology including anxiety and depression. The minority who experience grazing+LOC appear to have even greater risk of psychopathology. Moreover, there appears to be significant overlap with BED. Future research should explore whether these 2 maladaptive eating patterns benefit from similar treatment. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  20. A narrower gap of grazing intensity. Reply to Fetzel et al. 2017. Seasonality constrains to livestock grazing intensity

    USDA-ARS?s Scientific Manuscript database

    Fetzel et al. (2017) globally mapped the gap between observed and potential grazing intensity (GI): the ratio between consumption by livestock and ANPP. Fetzel et al. (2017) estimated grazing land, forage production and livestock demand at a half-degree resolution. They mapped GI below 15% for most ...

  1. Grazing behavior and production characteristics among cows differing in residual feed intake while grazing late season Idaho rangeland

    USDA-ARS?s Scientific Manuscript database

    The objectives were to determine if cows classified as either low- or high-residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter grazing activity over time. Thirty Hereford x Angus (LRFI = 16; HRFI = 14) 2-year-old cows grazed sagebrush-steppe for 78 d beginning 29 September 2016. Body...

  2. Pasture intake and milk production of dairy cows rotationally grazing on multi-species swards.

    PubMed

    Roca-Fernández, A I; Peyraud, J L; Delaby, L; Delagarde, R

    2016-09-01

    Increasing plant species diversity has been proposed as a means for enhancing annual pasture productivity and decreasing seasonal variability of pasture production facing more frequent drought scenarios due to climate change. Few studies have examined how botanical complexity of sown swards affects cow performance. A 2-year experiment was conducted to determine how sward botanical complexity, from a monoculture of ryegrass to multi-species swards (MSS) (grasses-legumes-forb), affect pasture chemical composition and nutritive value, pasture dry matter (DM) intake, milk production and milk solids production of grazing dairy cows. Five sward species: perennial ryegrass (L as Lolium), white clover and red clover (both referred to as T as Trifolium because they were always sown together), chicory (C as Cichorium) and tall fescue (F as Festuca) were assigned to four grazing treatments by combining one (L), three (LT), four (LTC) or five (LTCF) species. Hereafter, the LT swards are called mixed swards as a single combination of ryegrass and clovers, whereas LTC and LTCF swards are called MSS as a combination of at least four species from three botanical families. The experimental area (8.7 ha) was divided into four block replicates with a mineral nitrogen fertilisation of 75 kg N/ha per year for each treatment. In total, 13 grazing rotations were carried out by applying the same grazing calendar and the same pasture allowance of 19 kg DM/cow per day above 4 cm for all treatments. Clover represented 20% of DM for mixed and MSS swards; chicory represented 30% of DM for MSS and tall fescue represented 10% of DM for LTCF swards. Higher milk production (+1.1 kg/day) and milk solids production (+0.08 kg/day) were observed for mixed swards than for ryegrass swards. Pasture nutritive value and pasture DM intake were unaffected by the inclusion of clover. Pasture DM, organic matter and NDF concentrations were lower for MSS than for mixed swards. Higher milk production (+0.8 kg

  3. Integrating remote sensing and conventional grazing/browsing models for modelling carrying capacity in southern African rangelands

    NASA Astrophysics Data System (ADS)

    Adjorlolo, C.; Botha, J. O.; Mhangara, P.; Mutanga, O.; Odindi, J.

    2014-10-01

    Woody vegetation encroachment into grasslands or bush thickening, a global phenomenon, is transforming the Southern African grassland systems into savanna-like landscapes. Estimation of woody vegetation is important to rangeland scientists and land managers for assessing its impact on grass production and calculating its grazing and browsing capacity. Assessment of grazing and browsing components is often challenging because agro-ecological landscapes of this region are largely characterized by small scale and heterogeneous land-use-land-cover patterns. In this study, we investigated the utility of high spatial resolution remotely sensing data for modelling grazing and browsing capacity at landscape level. Woody tree density or Tree Equivalents (TE) and Total Leaf Mass (LMASS) data were derived using the Biomass Estimation for Canopy Volume (BECVOL) program. The Random Forest (RF) regression algorithm was assessed to establish relationships between these variables and vegetation indices (Simple Ratio and Normalized Difference Vegetation Index), calculated using the red and near infrared bands of SPOT5. The RF analysis predicted LMASS with R2 = 0.63 and a Root Mean Square Error (RMSE) of 1256 kg/ha compared to a mean of 2291kg/ha. TE was predicted with R2 = 0.55 and a RMSE = 1614 TE/ha compared to a mean of 3746 TE/ha. Next, spatial distribution maps of LMASS/ha and TE/ha were derived using separate RF regression models. The resultant maps were then used as input data into conventional grazing and browsing capacity models to calculate grazing and browsing capacity maps for the study area. This study provides a sound platform for integrating currently available and future remote sensing satellite data into rangeland carrying capacity modelling and monitoring.

  4. Figure and finish of grazing incidence mirrors

    SciTech Connect

    Takacs, P.Z. ); Church, E.L. . Army Armament Research, Development and Engineering Center)

    1989-08-01

    Great improvement has been made in the past several years in the quality of optical components used in synchrotron radiation (SR) beamlines. Most of this progress has been the result of vastly improved metrology techniques and instrumentation permitting rapid and accurate measurement of the surface finish and figure on grazing incidence optics. A significant theoretical effort has linked the actual performance of components used as x-ray wavelengths to their topological properties as measured by surface profiling instruments. Next-generation advanced light sources will require optical components and systems to have sub-arc second surface figure tolerances. This paper will explore the consequences of these requirements in terms of manufacturing tolerances to see if the present manufacturing state-of-the-art is capable of producing the required surfaces. 15 refs., 14 figs., 2 tabs.

  5. Riparian Meadow Response to Modern Conservation Grazing Management.

    PubMed

    Oles, Kristin M; Weixelman, Dave A; Lile, David F; Tate, Kenneth W; Snell, Laura K; Roche, Leslie M

    2017-09-01

    Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions.

  6. Examining ecological consequences of feral horse grazing using exclosures.

    USGS Publications Warehouse

    Beever, E.A.; Brussard, P.F.

    2000-01-01

    Although feral horses have inhabited western North America since the end of the 16th century, relatively little synecological research has been conducted to quantitatively characterize how they interact with ecosystem components. Because feral horses exhibit watering behavior markedly different from that of domestic cattle, it is particularly important to evaluate response of ecosystem elements near water sources to horse use. To assess this response, we performed live-trapping of small mammals and 2-tiered vegetative sampling in 2 mountain ranges in central Nevada in the interior Great Basin, USA. At low elevations, plots around horse-excluded springs exhibited notably greater plant species richness, percent cover, and abundance of grasses and shrubs, as well as more small mammal burrow entrances than plots at horse-grazed springs. At high elevations, meadows protected from grazing exhibited maximum vegetation heights 2.8 times greater than vegetation grazed by horses only and 4.5 times greater than vegetation grazed by horses and cattle. Species richness in quadrats was most different between the horse-and-cattle-grazed meadow and its ungrazed counterpart, suggesting the possibility of synergistic effects of horse and cattle grazing in the same location. This study, the first in the Great Basin to investigate quantitatively ecosystem consequences of feral horse use with exclosures, represents a preliminary step in identifying factors that determine the magnitude of horse grazing impacts. 

  7. Riparian Meadow Response to Modern Conservation Grazing Management

    NASA Astrophysics Data System (ADS)

    Oles, Kristin M.; Weixelman, Dave A.; Lile, David F.; Tate, Kenneth W.; Snell, Laura K.; Roche, Leslie M.

    2017-09-01

    Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions.

  8. Grazing behaviour, physical activity and metabolic profile of two Holstein strains in an organic grazing system.

    PubMed

    Thanner, S; Schori, F; Bruckmaier, R M; Dohme-Meier, F

    2014-12-01

    The challenge for sustainable organic dairy farming is identification of cows that are well adapted to forage-based production systems. Therefore, the aim of this study was to compare the grazing behaviour, physical activity and metabolic profile of two different Holstein strains kept in an organic grazing system without concentrate supplementation. Twelve Swiss (HCH ; 566 kg body weight (BW) and 12 New Zealand Holstein-Friesian (HNZ ; 530 kg BW) cows in mid-lactation were kept in a rotational grazing system. After an adaptation period, the milk yield, nutrient intake, physical activity and grazing behaviour were recorded for each cow for 7 days. On three consecutive days, blood was sampled at 07:00, 12:00 and 17:00 h from each cow by jugular vein puncture. Data were analysed using linear mixed models. No differences were found in milk yield, but milk fat (3.69 vs. 4.05%, P = 0.05) and milk protein percentage (2.92 vs. 3.20%, P < 0.01) were lower in HCH than in HNZ cows. Herbage intake did not differ between strains, but organic matter digestibility was greater (P = 0.01) in HCH compared to HNZ cows. The HCH cows spent less (P = 0.04) time ruminating (439 vs. 469 min/day) and had a lower (P = 0.02) number of ruminating boli when compared to the HNZ cows. The time spent eating and physical activity did not differ between strains. Concentrations of IGF-1 and T3 were lower (P ≤ 0.05) in HCH than HNZ cows. In conclusion, HCH cows were not able to increase dry matter intake in order to express their full genetic potential for milk production when kept in an organic grazing system without concentrate supplementation. On the other hand, HNZ cows seem to compensate for the reduced nutrient availability better than HCH cows but could not use that advantage for increased production efficiency. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  9. Quantifying the impact of livestock grazing on soil physical properties

    NASA Astrophysics Data System (ADS)

    Fučík, Petr; Zajíček, Antonín; Holubík, Ondřej

    2014-05-01

    Livestock grazing is considered to have a noticeable influence on soil properties, when pedocompaction / soil pore reduction induced either by cattle or sheeps may curtail water residence time and accelerate the beginning and volume of overland flow. However, direct measurements of soil physical parameters and their changes under different pastoral management are seldom reported in central European conditions. Knowledge about these alterations are indispensable for setting the proper, soil and water conservative grazing management in the view of increasing areas of pastures, not only in the Czech Republic. Impact of cattle grazing on changes of soil properties was studied in three experimental upland catchments in the Czech Republic, differing in soil characteristics and grazing management. Values of soil saturated hydraulic conductivity (Ks), assessed three times a year in-situ during 2012 - 2013 with pressure infiltrometers, were compared for grazed and ungrazed cambisols, pseudogleys and gleysols, for grazing intensity ranging from 0.5 to 2 Livestock units / ha. Soil bulk density (BD) and macroporosity (MP) were determined before and after grazing season every year with ring 100 cm3 steel cyllinders. These parameters were measured also on heavily treaded plots by cattle - hotspots - in each catchment. Ks values on grazed plots were significantly lower (on average by 39 - 66 %) than on ungrazed sites, BD values were reduced on average by 15 % and MP values were lower roughly about 22 % on grazed plots. Ks values on hotspots were lower by 50 - 90 %, BD values by 5 - 18 % and MP values by 8 - 28 % comparing to the rest of grazed areas. Decrease of soil infiltration capacity was influenced by grazing intensity and soil characteristics. The greatest reductions concerning infiltration capacity were manifested in soils being periodically waterlogged (either by surface or by groundwater). A profound influence on the infiltration process was revealed in pasture soils

  10. Interactions between global and grazing bifurcations in an impacting system.

    PubMed

    Mason, Joanna F; Piiroinen, Petri T

    2011-03-01

    It is well known that the locus of boundary crises in smooth systems contains gaps that give rise to periodic windows. We show that this phenomenon can also be observed in an impacting system, and that the mechanism by which these gaps are created is different. Namely, here gaps are created and disappear at points along the branches of boundary crises where they are intersected by branches of grazing bifurcations. We locate a novel type of double-crisis vertex which we call a grazing-crisis vertex. Additionally, we illustrate several types of basin-boundary metamorphosis that are intricately related with grazing bifurcations.

  11. Willow establishment in relation to cattle grazing on an eastern Oregon stream

    Treesearch

    Nancy L. Shaw; Warren P. Clary

    1996-01-01

    Natural regeneration and growth of coyote willow (Salix exigua Nutt. ssp. exigua) and whiplash willow (S. lasiandra Bemth. var. caudata [Nutt.] Sudw.) were monitored from 1987 to 1993 on a low-elevation eastern Oregon stream degraded by more than a century of heavy livestock grazing. Treatments were no grazing, moderate spring grazing, moderate fall grazing, and...

  12. Experimental Evidence for Grazing System Research: What Does it Tell Us?

    USDA-ARS?s Scientific Manuscript database

    Research on grazing systems has been conducted for the past 60 years and the experimental evidence consistently indicates that rotational grazing is comparable to continuous grazing on rangelands. For example, over 80% of the peer-reviewed studies reported that rotational grazing did not result in h...

  13. Plant Diversity: Effects of Grazing System and Stocking Rate in Northern Mixed-Grass Prairie

    USDA-ARS?s Scientific Manuscript database

    Effects of grazing system, stocking rate, and grazing system X stocking rate interactions, on plant diversity are poorly understood in rangelands. A grazing system (season-long and short-duration rotational grazing) X stocking rate (light: 16 steers•80 ha-1, moderate: 4 steers•12 ha-1 and heavy: 4 s...

  14. The interaction of diurnal grazing pattern, ruminal metabolism, nutrient supply and management in cattle

    USDA-ARS?s Scientific Manuscript database

    Daily herbage intake depends on several factors that govern the initiation and cessation of successive grazing bouts. Ruminal fill, which regulates grazing bout-eating behavior, is one such factor. Under grazing conditions, nutrient supply varies among grazing bouts, not only in amount, but also in ...

  15. Impact of processing on in vitro digestion of milk from grazing organic and confined conventional herds

    USDA-ARS?s Scientific Manuscript database

    Debate on differences between milk from grazing and non-grazing cows has not addressed the effects that standard processing may have on milk digestibility. In this study, raw milk from grazing organic (ORG) and non-grazing conventional (CONV) herds was adjusted to 0 and 3.25% fat and processed as fo...

  16. Fall and spring grazing influence fire ignitability and initial spread in shrub steppe communities

    USDA-ARS?s Scientific Manuscript database

    The interaction between grazing and fire influences ecosystems around the world. However, relatively little is known about the influence of grazing on fire, in particular ignition and initial spread and how it varies by grazing management differences. We investigated effects of fall grazing, spring...

  17. 25 CFR 161.300 - When is a permit needed to authorize grazing use?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is a permit needed to authorize grazing use? 161.300... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.300 When is a permit needed to authorize grazing... Navajo Partitioned Land for grazing purposes....

  18. 25 CFR 166.408 - Is the grazing rental rate established by the BIA adjusted periodically?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Is the grazing rental rate established by the BIA... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.408 Is the grazing rental rate established by the BIA adjusted...

  19. 25 CFR 161.207 - What livestock are authorized to graze?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What livestock are authorized to graze? 161.207 Section... LANDS GRAZING PERMITS General Provisions § 161.207 What livestock are authorized to graze? The following livestock are authorized to graze on the Navajo Partitioned Lands: horses, cattle, sheep, goats,...

  20. 25 CFR 161.300 - When is a permit needed to authorize grazing use?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is a permit needed to authorize grazing use? 161.300... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.300 When is a permit needed to authorize grazing... Navajo Partitioned Land for grazing purposes....

  1. 43 CFR 4130.6-2 - Nonrenewable grazing permits and leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Nonrenewable grazing permits and leases...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-2 Nonrenewable grazing permits and leases....

  2. 43 CFR 6304.25 - What special provisions apply to livestock grazing?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing? 6304.25 Section 6304.25 Public Lands: Interior Regulations Relating to Public Lands (Continued... Specifically Addressed by the Wilderness Act § 6304.25 What special provisions apply to livestock grazing? (a) If you hold a BLM grazing permit or grazing lease for land within a wilderness area, you may...

  3. 25 CFR 161.307 - When may a permittee commence grazing on Navajo Partitioned Land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When may a permittee commence grazing on Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land? The permittee may graze on Navajo Partitioned Land on the...

  4. 25 CFR 166.408 - Is the grazing rental rate established by the BIA adjusted periodically?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Is the grazing rental rate established by the BIA... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.408 Is the grazing rental rate established by the BIA adjusted...

  5. 25 CFR 161.207 - What livestock are authorized to graze?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What livestock are authorized to graze? 161.207 Section... LANDS GRAZING PERMITS General Provisions § 161.207 What livestock are authorized to graze? The following livestock are authorized to graze on the Navajo Partitioned Lands: horses, cattle, sheep, goats,...

  6. 25 CFR 161.307 - When may a permittee commence grazing on Navajo Partitioned Land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When may a permittee commence grazing on Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land? The permittee may graze on Navajo Partitioned Land on the...

  7. 43 CFR 4130.6-1 - Exchange-of-use grazing agreements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Exchange-of-use grazing agreements. 4130.6... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-1 Exchange-of-use grazing agreements. (a) An...

  8. Pasture-scale measurement of methane emissions of grazing cattle

    USDA-ARS?s Scientific Manuscript database

    Quantifying methane emission of cattle grazing on southern Great Plains pastures using micrometeorology presents several challenges. Cattle are elevated, mobile point sources of methane, so that knowing their location in relation to atmospheric methane concentration measurements becomes critical. St...

  9. An evidence-based assessment of prescribed grazing practices

    USDA-ARS?s Scientific Manuscript database

    Synthesis findings regarding the evidence-based assessment of prescribed grazing practices include: 1) stocking rate, in conjunction with appropriate temporal and spatial animal distribution, is a key management variable that influences numerous conservation outcomes, 2) assumptions regarding livest...

  10. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Forest Supervisor will prepare a charter to be filed with the Department and the Congress as required by... term grazing permittees for the area which the board represents requests that the board be dissolved...

  11. Nitrogen Mineralization by Acanthamoeba polyphaga in Grazed Pseudomonas paucimobilis Populations

    PubMed Central

    Sinclair, James L.; McClellan, J. Forbes; Coleman, David C.

    1981-01-01

    Nitrogen mineralization was studied in a simple grazing system in which the protozoan Acanthamoeba polyphaga was grown with the bacterium Pseudomonas paucimobilis (two soil organisms isolated from the shortgrass prairie in northern Colorado). In different experiments, either carbon or nitrogen was adjusted to be in limiting amounts. When carbon was limiting, grazers were almost entirely responsible for nitrogen mineralization, with bacteria themselves contributing little. When nitrogen was limiting, nitrogen mineralization by grazers permitted continued growth by the grazed bacteria and a greater bacterial biomass production. The increased growth of the grazed bacteria did not result in an increased total amount of carbon used, but the grazed bacteria used carbon more efficiently than the ungrazed bacteria. PMID:16345864

  12. 43 CFR 4110.2-3 - Transfer of grazing preference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... property and the grazing preference, in animal unit months, attached to that base property. (c) If a... the transfer. (e) If an unqualified transferee acquires rights in base property through operation...

  13. 43 CFR 4200.1 - Authority for grazing privileges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; LIVESTOCK... have been approved by the Office of Management and Budget under 44 U.S.C. 3507 and assigned clearance...

  14. 43 CFR 4200.1 - Authority for grazing privileges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; LIVESTOCK... have been approved by the Office of Management and Budget under 44 U.S.C. 3507 and assigned clearance...

  15. 43 CFR 4200.1 - Authority for grazing privileges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; LIVESTOCK... have been approved by the Office of Management and Budget under 44 U.S.C. 3507 and assigned clearance...

  16. Fire and grazing regulate belowground processes in tallgrass prairie

    USGS Publications Warehouse

    Johnson, Loretta C.; Matchett, John R.

    2001-01-01

    In tallgrass prairie, belowground processes are even more important than in forested systems because aboveground biomass and standing dead litter are periodically removed by frequent fires or grazers. Thus, studies that address factors regulating belowground processes are especially relevant for tallgrass prairie. We predicted that effects of grazing and burning differ belowground and that changes in root productivity caused by burning or grazing provide feedback that affects ecosystem fluxes of C and N. These differences in belowground response should be driven largely by changes in N dynamics and the degree to which burning and grazing affect the pathway and magnitude of N loss and the degree of N limitation in these systems. Fire, the major pathway of N loss in ungrazed tallgrass prairie, should result in reduced net N mineralization and N availability. We expected plants to compensate for increased N limitation by increasing their allocation to roots, as manifested in increased soil respiration and C cycling belowground. In contrast, grazing conserves N in the ecosystem by redistributing the N once contained in grass to labile forms in urine and dung. Thus, we predicted that grazing should increase N cycling rates and N availability to plants. Consequently, grazed plants should be less N limited and should allocate less C to roots and more to shoots. This, in turn, should decrease belowground C cycling, manifested as reduced soil CO2 flux.We explored the roles of grazing and burning on root growth in experimental watersheds at Konza Prairie, Kansas, USA. To assess effects of fire on root productivity, we installed root ingrowth cores in two watersheds without grazers that differ in fire frequency: annually vs. infrequently burned (four years since the last fire). To assess effects of grazing, we installed root ingrowth cores in an annually burned watershed grazed by bison and in fenced controls (exclosures). Within bison “grazing lawns,” root ingrowth cores

  17. Herds of methane chambers grazing bubbles

    NASA Astrophysics Data System (ADS)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  18. Fire management in fens and wet grasslands grazed by cattle

    USGS Publications Warehouse

    Middleton, Beth A.

    2006-01-01

    Managers grapple with the problem of shrub invasion in fens and wet grasslands, and the invasion of shrubs is a particular problem in newly acquired natural areas that were once grazed by cattle. The specific management for any particular fen or wet grassland depends greatly on its previous land-use history. Managers should have a clear understanding of the grazing and drainage history of newly acquired fens and wet grasslands so that well-informed management decisions can be made.

  19. Technical note: Monitoring grazing bites and walking activity with pedometers.

    PubMed

    Umemura, K

    2013-02-01

    Three types of pedometers installed on loosely fitted neck collars were investigated to determine the accuracy with which the devices measured the number of grazing bites performed by cows. The pedometer memory stored the summed number of bites over 1-h intervals for up to 10d, and the battery had a life of more than 3 mo. The values recorded by the pedometers were linearly related to the number of bites measured by visual observation and were unaffected by rumination. The correlation coefficients between the pedometer values and the number of bites were all >0.9. Circadian and day-to-day variations in the number of grazing bites were obtained by all 3 pedometers. The regression coefficients differed among the pedometers. The pedometers also responded to the occurrence of walking steps. The values recorded by the pedometers were linearly related to the observed number of walking steps. The correlation coefficients between the pedometer values and the number of steps were all >0.9. Although the number of walking steps affected the number of grazing bites, the number of bites greatly exceeded the number of walking steps. One type of pedometer, equipped with a 2-dimensional accelerometer, was used to analyze both grazing and walking behaviors. The back-forth and right-left movements of the pedometer had similar values during walking, whereas the values of the back-forth movements were greater during grazing. I conclude that pedometers can be used to measure the number of grazing bites but that this technique requires calibration to relate the pedometer values to the number of grazing bites. Observations of the back-forth and right-left movements of pedometers on neck collars will aid in distinguishing the grazing and walking behaviors of cows.

  20. Indicators of grazing impact in Inner Mongolian steppe ecosystems

    NASA Astrophysics Data System (ADS)

    Blank, B.; Breuer, L.; Butterbach-Bahl, K.; Frede, H.-G.

    2009-04-01

    The DFG research group 536 MAGIM (Matter fluxes in grasslands of Inner Mongolia as influenced by stocking rate) investigates the influence of grazing intensity on matter and water cycles in grazed steppe ecosystems of Inner Mongolia. This Sino-German co-operation applies an interdisciplinary approach to investigate major ecosystem functions and how they are affected by grazing and overgrazing. Within the research group an indicator system is developed to systemize the feedback of ecosystem parameters to the influence of grazing and to analyse, which parameter or parameter group reacts most sensitively. Parameters were measured at up to five different grazing intensities (from ungrazed to heavy grazed) and are related to four thematic indicator groups (plant productivity, atmosphere, pedosphere, hydrosphere). The parameters were scaled to allow assessing the influence of grazing intensity between different sets of parameters. For this the average value of a parameter at the lowest grazing intensity (ungrazed) was set 100%, so that the values at the other intensities could be scaled scaled adequately. Then the difference between highest and lowest grazing intensity was determined. According to this difference the influence of grazing was characterized as weak (< 20% difference), medium (20-40%), strong (40-60%) and very strong (> 60%). Impact of grazing on the parameters will be marked as weak (w), medium (m), strong (s) and very strong (vs) in the text. The group plant productivity includes the vegetation parameters aboveground biomass and belowground biomass. Belowground biomass (s) was significantly different between grazing treatments with the highest value at the ungrazed site (399.00 g m-2 a-1) and the lowest at the heavy grazed site (208.00 g m-2 a-1). Aboveground biomass (m) ranged between 91.33-131.67 g m-2 a-1 and differed significantly between the ungrazed and the heavy grazed site, again with higher values at the ungrazed site (Gao et al. 2008). The group

  1. Phosphorus translocation by red deer on a subalpine grassland in the central European Alps

    Treesearch

    Martin Schutz; Anita C. Risch; Gerald Achermann; Conny Thiel-Egenter; Deborah Page-Dumroese; Martin F. Jurgensen; Peter J. Edward

    2006-01-01

    We examined the role of red deer (Cervus elaphus L.) in translocating phosphorus (P) from their preferred grazing sites (short-grass vegetation on subalpine grasslands) to their wider home range in a subalpine grassland ecosystem in the Central European Alps. Phosphorus was used because it is the limiting nutrient in these grasslands. When we compared P removal of...

  2. Grazing envelope evolution towards Type IIb supernovae

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2017-09-01

    I propose a scenario where the majority of the progenitors of Type IIb supernovae (SNe IIb) lose most of their hydrogen-rich envelope during a grazing envelope evolution (GEE). In the GEE, the orbital radius of the binary system is about equal to the radius of the giant star, and the more compact companion accretes mass through an accretion disc. The accretion disc is assumed to launch two opposite jets that efficiently remove gas from the envelope along the orbit of the companion. The efficient envelope removal by jets prevents the binary system from entering a common envelope evolution, at least for part of the time. The GEE might be continuous or intermittent. I crudely estimate the total GEE time period to be in the range of about hundreds of years, for a continuous GEE, and up to few tens of thousands of years for intermittent GEE. The key new point is that the removal of envelope gas by jets during the GEE prevents the system from entering a common envelope evolution, and by that substantially increases the volume of the stellar binary parameter space that leads to SNe IIb, both to lower secondary masses and to closer orbital separations.

  3. Performance of second-season grazing cattle following different levels of parasite control in their first grazing season.

    PubMed

    Larsson, A; Uggla, A; Waller, P J; Höglund, J

    2011-01-10

    A 3-year grazing trial was performed during 2003-2005 on a commercial steer-producing farm in Sweden to study performance of second-season grazing (SSG) cattle following different levels of parasite exposure during their first grazing season. Initially, groups of 10 first-season grazing (FSG) cattle were each year assigned to four parasite control strategies: (1) turn-out onto pasture that during the previous year was grazed by SSG cattle, followed by a mid-July move to aftermath, (2) supplementation with concentrate and roughage for 4 weeks after turn-out, (3) no treatment, or (4) anthelmintic treatment (injectable doramectin) every fourth week. All animals were set stocked, except for those in group one. Next spring and following housing the cattle were turned out for their second grazing season onto approximately 25 ha communal pasturelands as a common mob. Weighing, faecal sampling and blood collection were performed at turn-out and then every 4 weeks for the 20-week grazing season. Faecal samples were also collected on day 10 after turn-out for detection of coccidian oocysts. Antibodies to Dictyocaulus viviparus were analysed at the time of their second housing period, and when elevated levels were recorded, stored serum samples from seropositive animals were analysed retrospectively. Results showed early-season weight losses of up to 47 kg in the SSG cattle. However, faecal egg counts were generally low and there was no correlation between SSG performance and treatment history as FSG cattle. Still, cumulative egg counts were significantly higher in animals that had been treated with anthelmintic as FSG cattle but serum pepsinogen concentrations showed no significant differences and the output of Eimeria alabamensis oocysts seldom exceeded 10,000 oocysts per gram faeces. Antibodies to D. viviparus were observed from July 2004 and from June 2005 but not in 2003. In 2004 and 2005, 64% and 83% of the animals, respectively, were seropositive for D. viviparus. It

  4. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management...

  5. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management...

  6. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management...

  7. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management...

  8. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations...

  9. Influence of grazing and available moisture on breeding densities of grassland birds in the central platte river valley, Nebraska

    USGS Publications Warehouse

    Kim, D.H.; Newton, W.E.; Lingle, G.R.; Chavez-Ramirez, F.

    2008-01-01

    We investigated the relationship between grassland breeding bird densities and both grazing and available moisture in the central Platte River Valley. Nebraska between 1980 and 1996. We also compared species richness and community similarity of breeding birds in sedge (Carex spp.) meadows and mesic grasslands. Densities of two species had a significant relationship with grazing and six of seven focal species had a significant relationship with available moisture. Bobolink (Dolichonyx oryzivorus) and Brown-headed Cowbird (Molothrus ater) densities were lower in grazed plots compared to ungrazed plots, whereas Red-winged Blackbird (Agelaius phoeniceus) densities were greater in sedge-meadow plots compared to mesic grassland plots. Bobolink, Dickcissel (Spiza americana). and Brown-headed Cowbird were negatively associated with available moisture with breeding densities peaking during the driest conditions. Our results suggest that wet conditions increase species richness for the community through addition of wetland-dependant and wetland-associated birds, but decrease densities of ground-nesting grassland birds in wet-meadow habitats, whereas dry conditions reduce species richness but increase the density of the avian assemblage. We propose that wet-meadow habitats serve as local refugia for grassland-nesting birds during local or regional droughts.

  10. Initiation of methane turbulent flux measurements over a grazed grassland in Belgium

    NASA Astrophysics Data System (ADS)

    Dumortier, Pierre; Aubinet, Marc; Chopin, Henri; Debacq, Alain; Jérome, Elisabeth; Beckers, Yves; Heinesch, Bernard

    2013-04-01

    Methane fluxes emitted by a grazed meadow were measured continuously during the 2012 grazing season at the Dorinne Terrestrial Observatory (50° 18' 44" N; 4° 58' 07" E; 248 m asl.) in Belgium. Measurements were made with the eddy covariance technique, using a fast CH4 analyzer (Picarro G2311-f). Carbon dioxide fluxes (LI-7000) and various micro-meteorological and soil variables, biomass growth and stocking rate evolution were also measured at the site. The site is an intensively pastured meadow of 4.2 ha managed according to the regional usual practices where up to 30 cows are grazing simultaneously. N2O emissions are currently measured through dynamic closed chambers (Beekkerk van Ruth et al., Geophysical Research Abstracts. Vol. 15, EGU2013-3211, 2013) and the carbon budget of the site has already been investigated (Jerome et al. Geophysical Research Abstracts, Vol. 15, EGU2013-6989, 2013). As no CH4 measurements were available, CH4 fluxes were estimated on the basis of dry matter intake by the cows and a conversion factor obtained from a literature review. We want to improve this estimation by measuring CH4 fluxes, identifying their main environmental drivers and understanding diurnal and annual exchange patterns. Methane emissions were found strongly related with cattle stocking rate with a slope of 7.34±0.78 mol CH4 day-1 LSU-1. Up to now, no methane absorption has been observed, the meadow behaving as a methane emitter, even in the absence of cows. In the absence of cows, no significant relation can be established up to now between methane emissions and environmental parameters. No clear diurnal evolution is observed, neither during grazing periods nor during cow free periods. During cow presence periods, fluxes are highly variable, probably due to cow movements in and out the measurement footprint and cow digestion rhythm. Further developments are ongoing in order to improve cattle geo-localization through individual home-made GPS devices and infra-red

  11. Grazing-induced BVOC fluxes from a managed grassland

    NASA Astrophysics Data System (ADS)

    Mozaffar, Ahsan; Schoon, Niels; Bachy, Aurelie; Digrado, Anthony; Heinesch, Bernard; Aubinet, Marc; Fauconnier, Marie-laure; Delaplace, Pierre; Dujardin, Patrick; Amelynck, Crist

    2017-04-01

    Grassland ecosystems cover one fourth of the Earth's land surface and are both sources and sinks of Biogenic Volatile Organic Compounds (BVOCs) which play an important role in atmospheric chemistry and air pollution. The use of grassland for cattle breeding is a common practice in many parts of the world. As it has been widely demonstrated that plants emit large bursts of BVOCs when they are mechanically damaged, grass tearing and trampling during grazing are expected to induce large BVOC emissions as well. Nevertheless, to the best of our knowledge, no study has been performed on BVOC fluxes from grazed grassland yet. Therefore investigations were performed using automated dynamic chambers in a managed grassland in Belgium over the 2015 and 2016 growing season. BVOC fluxes, together with carbon dioxide (CO2) and water vapor (H2O) fluxes from grazed and undisturbed grassland were followed simultaneously using PTR-MS (Proton Transfer Reaction-Mass Spectrometry) and a LI-840 non-dispersive IR gas analyzer. In addition, air in the chamber was sampled occasionally for GC-MS (Gas Chromatography-Mass Spectrometry) analysis to assist compound identification. Significant differences between grazed and undisturbed grassland patches were observed in terms of BVOC, CO2 and H2O vapor fluxes. Grazing by cows was found to result in enhanced emissions of several BVOCs such as methanol, acetaldehyde, acetone, acetic acid and Green Leaf Volatiles (GLVs), and induced BVOC emissions generally lasted for around 5 days following a grazing event. Quantitative data on the impact of grazing on BVOC, CO2 and H2O exchange between grassland and the atmosphere will be presented, and correlations between BVOC fluxes and environmental conditions will be discussed.

  12. Functional diversity increases ecological stability in a grazed grassland.

    PubMed

    Hallett, Lauren M; Stein, Claudia; Suding, Katharine N

    2017-03-01

    Understanding the factors governing ecological stability in variable environments is a central focus of ecology. Functional diversity can stabilize ecosystem function over time if one group of species compensates for an environmentally driven decline in another. Although intuitively appealing, evidence for this pattern is mixed. We hypothesized that diverse functional responses to rainfall will increase the stability of vegetation cover and biomass across rainfall conditions, but that this effect depends on land-use legacies that maintain functional diversity. We experimentally manipulated grazing in a California grassland to create land-use legacies of low and moderate grazing, across which we implemented rainout shelters and irrigation to create dry and wet conditions over 3 years. We found that the stability of the vegetation cover was greatly elevated and the stability of the biomass was slightly elevated across rainfall conditions in areas with histories of moderate grazing. Initial functional diversity-both in the seed bank and aboveground-was also greater in areas that had been moderately grazed. Rainfall conditions in conjunction with this grazing legacy led to different functional diversity patterns over time. Wet conditions led to rapid declines in functional diversity and a convergence on resource-acquisitive traits. In contrast, consecutively dry conditions maintained but did not increase functional diversity over time. As a result, grazing practices and environmental conditions that decrease functional diversity may be associated with lasting effects on the response of ecosystem functions to drought. Our results demonstrate that theorized relationships between diversity and stability are applicable and important in the context of working grazed landscapes.

  13. Grazing impact of copepods on phytoplankton in the Bohai Sea

    NASA Astrophysics Data System (ADS)

    Li, Chaolun; Wang, Rong; Sun, Song

    2003-11-01

    During spring (April/May 1999) and autumn (September/October 1998) cruises in the Bohai Sea, China, copepods were the dominant components of mesozooplankton, the most abundant species being Calanus sinicus, Centropages mcmurrichi, Paracalanus parvus, Acartia bifilosa and Oithona similis. Pigment ingestion rates by three size classes of copepods (200-500, 500-1000 and >1000 μm) were measured. In the south of the investigation area, gut pigment content (GPC), individual pigment-specific ingestion rates and grazing impacts on phytoplankton were lower in spring than in autumn. In the central area, GPC and individual pigment-specific ingestion rates were higher in spring than in autumn. The grazing impact on phytoplankton by the copepod assemblages was lower in spring than in autumn, however, because of the relatively smaller biomass in spring. In the western area where the Bohai Sea joins the Yellow Sea, GPC, individual pigment-specific ingestion rates and grazing impacts on phytoplankton were higher in spring than in autumn. Among the three size groups, the small-sized animals (200-500 μm) contributed more than 50% (range 38-98%) of the total copepod grazing during both cruises. The grazing impact on phytoplankton by copepods was equivalent to 11.9% (range 3.0-37.1%) of the chlorophyll- a standing stock and 53.3% (range 21.4-91.4%) of the primary production during the spring cruise. Grazing impact was equivalent to 6.3% (range 2.0-11.6%) of the chlorophyll- a standing stock and >100% (range 25.7-141.6%) of the primary production during the autumn cruise. The copepod community apparently consumed only a modest proportion of the standing stock of phytoplankton during spring and autumn blooms. They did, however, sometimes graze a significant proportion of daily primary production and hence were presumably able to limit the rate of further accumulation of phytoplankton, or even to prevent it.

  14. Near grazing scattering from non-Gaussian ocean surfaces

    NASA Technical Reports Server (NTRS)

    Kim, Yunjin; Rodriguez, Ernesto

    1993-01-01

    We investigate the behavior of the scattered electromagnetic waves from non-Gaussian ocean surfaces at near grazing incidence. Even though the scattering mechanisms at moderate incidence angles are relatively well understood, the same is not true for near grazing rough surface scattering. However, from the experimental ocean scattering data, it has been observed that the backscattering cross section of a horizontally polarized wave can be as large as the vertical counterpart at near grazing incidence. In addition, these returns are highly intermittent in time. There have been some suggestions that these unexpected effects may come from shadowing or feature scattering. Using numerical scattering simulations, it can be shown that the horizontal backscattering cannot be larger than the vertical one for the Gaussian surfaces. Our main objective of this study is to gain a clear understanding of scattering mechanisms underlying the near grazing ocean scattering. In order to evaluate the backscattering cross section from ocean surfaces at near grazing incidence, both the hydrodynamic modeling of ocean surfaces and an accurate near grazing scattering theory are required. For the surface modeling, we generate Gaussian surfaces from the ocean surface power spectrum which is derived using several experimental data. Then, weakly nonlinear large scale ocean surfaces are generated following Longuet-Higgins. In addition, the modulation of small waves by large waves is included using the conservation of wave action. For surface scattering, we use MOM (Method of Moments) to calculate the backscattering from scattering patches with the two scale shadowing approximation. The differences between Gaussian and non-Gaussian surface scattering at near grazing incidence are presented.

  15. Near grazing scattering from non-Gaussian ocean surfaces

    NASA Technical Reports Server (NTRS)

    Kim, Yunjin; Rodriguez, Ernesto

    1993-01-01

    We investigate the behavior of the scattered electromagnetic waves from non-Gaussian ocean surfaces at near grazing incidence. Even though the scattering mechanisms at moderate incidence angles are relatively well understood, the same is not true for near grazing rough surface scattering. However, from the experimental ocean scattering data, it has been observed that the backscattering cross section of a horizontally polarized wave can be as large as the vertical counterpart at near grazing incidence. In addition, these returns are highly intermittent in time. There have been some suggestions that these unexpected effects may come from shadowing or feature scattering. Using numerical scattering simulations, it can be shown that the horizontal backscattering cannot be larger than the vertical one for the Gaussian surfaces. Our main objective of this study is to gain a clear understanding of scattering mechanisms underlying the near grazing ocean scattering. In order to evaluate the backscattering cross section from ocean surfaces at near grazing incidence, both the hydrodynamic modeling of ocean surfaces and an accurate near grazing scattering theory are required. For the surface modeling, we generate Gaussian surfaces from the ocean surface power spectrum which is derived using several experimental data. Then, weakly nonlinear large scale ocean surfaces are generated following Longuet-Higgins. In addition, the modulation of small waves by large waves is included using the conservation of wave action. For surface scattering, we use MOM (Method of Moments) to calculate the backscattering from scattering patches with the two scale shadowing approximation. The differences between Gaussian and non-Gaussian surface scattering at near grazing incidence are presented.

  16. Levels of supplementation for grazing beef heifers.

    PubMed

    Cabral, Carla Heloisa Avelino; Paulino, Mario Fonseca; Detmann, Edenio; de Campos Valadares Filho, Sebastião; de Barros, Lívia Vieira; Valente, Eriton Egidio Lisboa; de Oliveira Bauer, Maristela; Cabral, Carlos Eduardo Avelino

    2014-06-01

    The objective of this experiment was to evaluate the effect of providing different levels of a supplement on the nutritional characteristics and productive performance of heifers on pasture during the rainy-dry transition and dry season in Brazil or tropical area. Thirty crossbred heifers with predominance of Zebu breed were used in a completely randomized experimental design. Treatments consisted of a mineral supplement and 0.5, 1.0, 1.5, or 2.0 kg/animal/d of a protein supplement containing 300 g crude protein (CP)/kg of dry matter (DM). In the rainy-dry transition season there was quadratic effect of the protein supplementation (p<0.10) on daily weight gain (DWG). A linear relationship (p<0.10) was found between increasing supplement intake and intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non fibrous carbohydrates (NFC) and total digestible nutrients (TDN). Coefficients of apparent digestibility of CP, EE, and NFC increased linearly (p<0.10) with increasing supplement levels, but there was no effect on the DM apparent digestibility (p>0.10); the microbial efficiency (g CPmic/kg TDN) and the relationship of microbial nitrogen flow with nitrogen intake (g/g nitrogen intake) were negative linear profiles. In the dry season, the descriptive pattern least squares means showed a trend of stabilization of DWG from the supply of 0.98 kg of protein supplement; the intakes of DM, OM, CP, EE, NFC, and TDN showed increasing linear relationship (p<0.10) with protein supplement levels; the means of apparent digestibility coefficients of the different dietary fractions presented a linear-response-plateau (LRP); the microbial nitrogen flow (g/d) showed positive linear profile (p<0.10) for supplementation levels. It is concluded that supplementation improves the productive performance of grazing heifers and that 1.0 kg/d of supplement per animal gives the maximum increment of weight gain.

  17. Development of Adjustable Grazing Incidence Optics

    NASA Astrophysics Data System (ADS)

    Reid, Paul B.; Davis, W.; Schwartz, D. A.; Trolier-McKinstry, S.; Wilke, R. H. T.

    2010-03-01

    We report on the development of adjustable grazing incidence optics. We are developing bimorph mirrors for high resolution (sub-arc second) imaging. Bimorph mirrors consist of a thin layer of piezo-electric material deposited on the back surface of a thin (< 0.4 mm) thermally formed glass or electroplated metal segmented mirror. Voltage applied across the thickness of the piezo produces a strain in the plane of the mirror surface. The strain produces bending of the mirror similar to the bi-metallic effect. No reaction structure is necessary, which allows one to densely nest mirror shells for large effective area. A pixilated array of outer electrodes on the piezo material localizes the strain to the particular piezo "pixel.” Mirror figure errors are corrected (on-orbit) via induced localized deformations. We have successfully deposited a 1-micrometer thick layer of the piezo-electric material lead-zirconate-titanate (PZT) on thin glass mirrors. We report on the electrical and mechanical properties of the bimorph mirrors, and mirror requirements. We discuss finite element modeling of bimorph mirrors. In particular, we focus on how a difference in mirror mounting affects the influence functions ( the induced deformations). We are also developing the use of electrostrictive adjusters for moderate resolution (a few arc second) imaging. Electroplated nickel/cobalt full shells are mounted together using the adjusters. The adjusters are arrayed axially and tangentially between shells, with their adjustable dimension in the radial direction. Each shell is adjusted and fixed in place during mirror assembly, starting with the innermost shell. We review finite element modeling of the adjustable optics and the application of the adjustment system to correct manufacturing errors. We discuss initial tests using electrostrictive adjusters to change the shape of flat mirror segments. This work is supported by NASA Contract NNX09AE87G and a grant from the Gordon and Betty Moore

  18. Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment.

    PubMed

    Kay, Geoffrey M; Mortelliti, Alessio; Tulloch, Ayesha; Barton, Philip; Florance, Daniel; Cunningham, Saul A; Lindenmayer, David B

    2016-06-17

    Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape-scale replicated grazing experiment (15,000 km(2) , 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground-dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch-occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine-scale grazing attributes is essential for advancing grazing as a conservation strategy.

  19. The effects of timing of grazing on plant and arthropod communities in high-elevation grasslands.

    PubMed

    Davis, Stacy C; Burkle, Laura A; Cross, Wyatt F; Cutting, Kyle A

    2014-01-01

    Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season.

  20. The Effects of Timing of Grazing on Plant and Arthropod Communities in High-Elevation Grasslands

    PubMed Central

    Davis, Stacy C.; Burkle, Laura A.; Cross, Wyatt F.; Cutting, Kyle A.

    2014-01-01

    Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season. PMID:25338008

  1. Trade patterns facilitating highly pathogenic avian influenza virus dissemination in the free-grazing layer duck system in Vietnam.

    PubMed

    Meyer, A; Dinh, T X; Han, T A; Do, D V; Nhu, T V; Pham, L T; Nguyen, T T T; Newman, S; Häsler, B; Pfeiffer, D U; Vergne, T

    2017-08-16

    Highly pathogenic avian influenza (HPAI) viruses continue to threaten smallholder poultry producers in several South-east Asian countries, including Vietnam. In particular, the free-grazing duck system has been repeatedly highlighted as a major risk factor for HPAI outbreaks. Free-grazing ducks, which scavenge on rice paddies after the harvest, account for a large proportion of the duck population in Vietnam and the wider South-east Asian region. However, the structure and dynamics of the free-grazing duck production from farm to consumption has not been described for Vietnam. In this study, we used a value chain approach to provide a complete picture of the actors involved in the production and marketing of free-grazing duck eggs and spent layer ducks, as well as to investigate the governance structure of this food system. Group interviews and key informant interviews were conducted in two provinces located in the Mekong River Delta (MRD) and the Red River Delta (RRD). The results presented here highlight similarities and differences in farming and trade practices between the two provinces. The trade of spent layer ducks involved large volumes of live ducks being sent to China and Cambodia for consumption, generating a substantial risk of transboundary spread of pathogens, including HPAI viruses. We describe the major role of "duck yards", which act as hubs in the northbound trade of spent layer ducks. These yards should be considered as essential links in the value chain of spent layer ducks when considering HPAI surveillance and control. The veterinary authorities are only marginally involved in the value chain activities, and their influence could be strengthened by increasing surveillance activities for instance in duck yards. Last, we discuss the dynamics of the duck value chain and further implications for future HPAI management policies. © 2017 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

  2. Breeding bird response to cattle grazing of a cottonwood bottomland

    USGS Publications Warehouse

    Sedgwick, James A.; Knopf, Fritz L.

    1987-01-01

    We studied avian habitat relationships and the impact of grazing on breeding densities of selected migratory birds in a plains cottonwood (Populus sargentii) bottomland in northeastern Colorado. Five 16-ha plots served as controls and 5 were fenced and fall-grazed October-November 1982-84 following a season of pre-treatment study in the spring of 1982. We focused our analysis on bird species directly dependent on the grass-herb-shrub layer of vegetation for foraging, nesting, or both. The guild included house wren (Troglodytes aedon), brown thrasher (Toxostoma rufum), American robin (Turdus migratorius), common yellowthroat (Geothlypis trichas), yellow-breasted chat (Icteria virens), and rufous-sided towhee (Pipilo erythropthalmus). Moderate, late-fall grazing had no detectable impact on calculated densities of any of the 6 species, implying that proper seasonal grazing of a cottonwood floodplain is, at least initially (3 years), compatible with migratory bird use of a site for breeding. Habitat associations suggested that common yellowthroats and yellow-breasted chats were most unique and most likely to respond negatively to higher levels of grazing. We suggest that these latter 2 species are appropriate ecological indicators of the quality of ground-shrub vegetation as breeding bird habitats in lowland floodplains of the Great Plains.

  3. Suspected photosensitisation in lambs grazing birdsfoot trefoil (Lotus corniculatus).

    PubMed

    Stafford, K J; West, D M; Alley, M R; Waghorn, G C

    1995-06-01

    Suspected photosensitisation occurred in three groups of lambs grazing birdsfoot trefoil (Lotus corniculatus c.v. Grasslands Goldie). In one group, sucking lambs aged about 10 weeks, grazing birdsfoot trefoil, developed skin lesions while lambs of a similar age and from the same flock grazing lucerne (Medicago sativa) or a mixed sward of both species showed no signs of photosensitisation. Affected lambs had lesions on their backs and ears. In a few animals the tips of the ears were shortened by 2-3 cm. In the affected lambs, serum liver enzymes (gamma-glutamyltransferase, glutamate dehydrogenase), bilirubin and serum Vitamin B12 levels were within the normal range. At necropsy, no significant pathological changes were detected in the liver and histological changes in the skin were consistent with primary photosensitisation. In the second group, three of 80 weaned lambs grazing the same birdsfoot trefoil at a restricted intake were affected in the same manner as the first group. In the third group, 15 animals from 28 sets of sucking twin lambs were also affected. In only two sets of twins were both lambs affected. None of the ewes grazing with the lambs in the first or third groups showed any clinical signs of photosensitisation.

  4. Carbon sequestration in grasslands: grazing versus fire under climate change

    NASA Astrophysics Data System (ADS)

    Bachelet, D. M.; Kelly, R.; Parton, W. J.

    2009-12-01

    We simulated different levels of grazing and frequencies of fire using the biogeochemical model DAYCENT across a climate gradient from Montana to New Mexico to look at their long-term implications on carbon sequestration in grasslands. We also used 3 future climate scenarios and 2 CO2 emission levels to estimate interactions between disturbance and climate. In all cases, total ecosystem carbon was driven by grazing pressure with carbon stocks declining by 15-35% under moderate to heavy grazing. Fire frequency had no effect on carbon levels when 50% of the aboveground biomass was consumed by grazers and has the most impact when no grazing occurred. Warmer drier climate scenarios increased the stress to growth and caused declines in carbon stocks unless a CO2 fertilization effect increased the water use efficiency. Again, under future climate change scenario, grazing had a greater impact than fire frequency in defining the overall levels of total ecosystem carbon. Potential woody plant invasion of grasslands would alter the role of disturbance on carbon sequestration potential since frequent fires would remove shrubs from the landscape reducing the potential for increased aboveground carbon stocks with lower palatability to grazers than grasses.

  5. The influence of intensively managed rotational grazing, traditional continuous grazing, and confinement housing on bulk tank milk quality and udder health.

    PubMed

    Goldberg, J J; Wildman, E E; Pankey, J W; Kunkel, J R; Howard, D B; Murphy, B M

    1992-01-01

    Monthly bulk tank milk samples and veterinary records were analyzed for 1 yr on 15 Vermont dairy farms. Data were evaluated using ANOVA to compare effects of grazing management systems on milk quality and udder health. Systems evaluated were intensively managed rotational grazing, traditional continuous grazing, and confinement housing. Bulk tank samples were evaluated for standard plate count, bacterial type counts on tryptose-blood-esculin agar, and SCC. Veterinary records were evaluated for incidence of clinical mastitis, udder edema, and teat injuries. Within- and between-treatment group analyses were conducted by season, herd size, and udder sanitation systems. Mean standard plate counts were lower in rotationally grazed herds than counts of confined herds during the grazing season. Similarly, rotationally grazed herds with fewer than 60 cows had lower standard plate counts than confined herds of similar size. Mean bulk tank counts of streptococci other than Streptococcus agalactiae during the grazing season differed among treatments. The lowest counts occurred in rotationally grazed herds. Among herd using predip products recognized as efficacious, fewer streptococci other than S. agalactiae were isolated from bulk tank milk of rotationally grazed herds than confined herds. Rotationally grazed herds using postdips recognized as efficacious had lower SCC than those using unrecognized postdips. No udder health differences were observed among grazing treatments.

  6. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    NASA Astrophysics Data System (ADS)

    Yun, Hee Young; Cruz, Joana; Treitschke, Michaela; Wahl, Martin; Molis, Markus

    2007-09-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown ( Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds ( Gelidium sesquipedale, Sphaerococcus coronopifolius) from São Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga-herbivore interactions.

  7. Genotype effects on body temperature in dairy cows under grazing conditions in a hot climate including evidence for heterosis

    NASA Astrophysics Data System (ADS)

    Dikmen, S.; Martins, L.; Pontes, E.; Hansen, P. J.

    2009-07-01

    We compared diurnal patterns of vaginal temperature in lactating cows under grazing conditions to evaluate genotype effects on body temperature regulation. Genotypes evaluated were Holstein, Jersey, Jersey × Holstein and Swedish Red × Holstein. The comparison of Holstein and Jersey versus Jersey × Holstein provided a test of whether heterosis effects body temperature regulation. Cows were fitted with intravaginal temperature recording devices that measured vaginal temperature every 15 min for 7 days. Vaginal temperature was affected by time of day ( P < 0.0001) and genotype × time ( P < 0.0001) regardless of whether days in milk and milk yield were used as covariates. Additional analyses indicated that the Swedish Red × Holstein had a different pattern of vaginal temperatures than the other three genotypes (Swedish Red × Holstein vs others × time; P < 0.0001) and that Holstein and Jersey had a different pattern than Jersey × Holstein [(Holstein + Jersey vs Jersey × Holstein) × time, P < 0.0001]. However, Holstein had a similar pattern to Jersey [(Holstein vs Jersey) × time, P > 0.10]. These genotype × time interactions reflect two effects. First, Swedish Red × Holstein had higher vaginal temperatures than the other genotypes in the late morning and afternoon but not after the evening milking. Secondly, Jersey × Holstein had lower vaginal temperatures than other genotypes in the late morning and afternoon and again in the late night and early morning. Results point out that there are effects of specific genotypes and evidence for heterosis on regulation of body temperature of lactating cows maintained under grazing conditions and suggest that genetic improvement for thermotolerance through breed choice or genetic selection is possible.

  8. Genotype effects on body temperature in dairy cows under grazing conditions in a hot climate including evidence for heterosis.

    PubMed

    Dikmen, S; Martins, L; Pontes, E; Hansen, P J

    2009-07-01

    We compared diurnal patterns of vaginal temperature in lactating cows under grazing conditions to evaluate genotype effects on body temperature regulation. Genotypes evaluated were Holstein, Jersey, Jersey x Holstein and Swedish Red x Holstein. The comparison of Holstein and Jersey versus Jersey x Holstein provided a test of whether heterosis effects body temperature regulation. Cows were fitted with intravaginal temperature recording devices that measured vaginal temperature every 15 min for 7 days. Vaginal temperature was affected by time of day (P < 0.0001) and genotype x time (P < 0.0001) regardless of whether days in milk and milk yield were used as covariates. Additional analyses indicated that the Swedish Red x Holstein had a different pattern of vaginal temperatures than the other three genotypes (Swedish Red x Holstein vs others x time; P < 0.0001) and that Holstein and Jersey had a different pattern than Jersey x Holstein [(Holstein + Jersey vs Jersey x Holstein) x time, P < 0.0001]. However, Holstein had a similar pattern to Jersey [(Holstein vs Jersey) x time, P > 0.10]. These genotype x time interactions reflect two effects. First, Swedish Red x Holstein had higher vaginal temperatures than the other genotypes in the late morning and afternoon but not after the evening milking. Secondly, Jersey x Holstein had lower vaginal temperatures than other genotypes in the late morning and afternoon and again in the late night and early morning. Results point out that there are effects of specific genotypes and evidence for heterosis on regulation of body temperature of lactating cows maintained under grazing conditions and suggest that genetic improvement for thermotolerance through breed choice or genetic selection is possible.

  9. Levels of Supplementation for Grazing Beef Heifers

    PubMed Central

    Cabral, Carla Heloisa Avelino; Paulino, Mario Fonseca; Detmann, Edenio; de Campos Valadares Filho, Sebastião; de Barros, Lívia Vieira; Valente, Ériton Egidio Lisboa; de Oliveira Bauer, Maristela; Cabral, Carlos Eduardo Avelino

    2014-01-01

    The objective of this experiment was to evaluate the effect of providing different levels of a supplement on the nutritional characteristics and productive performance of heifers on pasture during the rainy-dry transition and dry season in Brazil or tropical area. Thirty crossbred heifers with predominance of Zebu breed were used in a completely randomized experimental design. Treatments consisted of a mineral supplement and 0.5, 1.0, 1.5, or 2.0 kg/animal/d of a protein supplement containing 300 g crude protein (CP)/kg of dry matter (DM). In the rainy-dry transition season there was quadratic effect of the protein supplementation (p<0.10) on daily weight gain (DWG). A linear relationship (p<0.10) was found between increasing supplement intake and intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non fibrous carbohydrates (NFC) and total digestible nutrients (TDN). Coefficients of apparent digestibility of CP, EE, and NFC increased linearly (p<0.10) with increasing supplement levels, but there was no effect on the DM apparent digestibility (p>0.10); the microbial efficiency (g CPmic/kg TDN) and the relationship of microbial nitrogen flow with nitrogen intake (g/g nitrogen intake) were negative linear profiles. In the dry season, the descriptive pattern least squares means showed a trend of stabilization of DWG from the supply of 0.98 kg of protein supplement; the intakes of DM, OM, CP, EE, NFC, and TDN showed increasing linear relationship (p<0.10) with protein supplement levels; the means of apparent digestibility coefficients of the different dietary fractions presented a linear-response-plateau (LRP); the microbial nitrogen flow (g/d) showed positive linear profile (p<0.10) for supplementation levels. It is concluded that supplementation improves the productive performance of grazing heifers and that 1.0 kg/d of supplement per animal gives the maximum increment of weight gain. PMID:25050018

  10. Community responses of arthropods to a range of traditional and manipulated grazing in shortgrass steppe.

    PubMed

    Newbold, T A Scott; Stapp, Paul; Levensailor, Katherine E; Derner, Justin D; Lauenroth, William K

    2014-06-01

    Responses of plants to grazing are better understood, and more predictable, than those of consumers in North American grasslands. In 2003, we began a large-scale, replicated experiment that examined the effects of grazing on three important arthropod groups-beetles, spiders, and grasshoppers-in shortgrass steppe of north-central Colorado. We investigated whether modifications of the intensity and seasonality of livestock grazing alter the structure and diversity of macroarthropod communities compared with traditional grazing practices. Treatments represented a gradient of grazing intensity by cattle and native herbivores: long-term grazing exclosures; moderate summer grazing (the traditional regime); intensive spring grazing; intensive summer grazing; and moderately summer-grazed pastures also inhabited by black-tailed prairie dogs (Cynomys ludovicianus Ord). Beetles and spiders were the most common groups captured, comprising 60% and 21%, respectively, of 4,378 total pitfall captures. Grasshopper counts were generally low, with 3,799 individuals observed and densities <4 m(-2). Two years after treatments were applied, vegetation structure differed among grazing treatments, responding not only to long-term grazing conditions, but also to the short-term, more-intensive grazing manipulations. In response, arthropods were, in general, relatively insensitive to these grazing-induced structural changes. However, species-level analyses of one group (Tenebrionidae) revealed both positive and negative effects of grazing treatments on beetle richness and activity-density. Importantly, these responses to grazing were more pronounced in a year when spring-summer rainfall was low, suggesting that both grazing and precipitation-which together may create the greatest heterogeneity in vegetation structure-are drivers of consumer responses in this system.

  11. Seeing Red

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This New Horizons image of Jupiter's volcanic moon Io was taken at 13:05 Universal Time during the spacecraft's Jupiter flyby on February 28, 2007. It shows the reddish color of the deposits from the giant volcanic eruption at the volcano Tvashtar, near the top of the sunlit crescent, as well as the bluish plume itself and the orange glow of the hot lava at its source. The relatively unprocessed image on the left provides the best view of the volcanic glow and the plume deposits, while the version on the right has been brightened to show the much fainter plume, and the Jupiter-lit night side of Io.

    New Horizons' color imaging of Io's sunlit side was generally overexposed because the spacecraft's color camera, the super-sensitive Multispectral Visible Imaging Camera (MVIC), was designed for the much dimmer illumination at Pluto. However, two of MVIC's four color filters, the blue and 'methane' filter (a special filter designed to map methane frost on the surface of Pluto at an infrared wavelength of 0.89 microns), are less sensitive than the others, and thus obtained some well-exposed views of the surface when illumination conditions were favorable. Because only two color filters are used, rather than the usual three, and because one filter uses infrared light, the color is only a rough approximation to what the human eye would see.

    The red color of the Tvashtar plume fallout is typical of Io's largest volcanic plumes, including the previous eruption of Tvashtar seen by the Galileo and Cassini spacecraft in 2000, and the long-lived Pele plume on the opposite side of Io. The color likely results from the creation of reddish three-atom and four-atom sulfur molecules (S3 and S4) from plume gases rich in two-atom sulfur molecules (S2 After a few months or years, the S3 and S4 molecules recombine into the more stable and familiar yellowish form of sulfur consisting of eight-atom molecules (S8), so these red deposits are only seen around recently-active Io

  12. Seeing Red

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This New Horizons image of Jupiter's volcanic moon Io was taken at 13:05 Universal Time during the spacecraft's Jupiter flyby on February 28, 2007. It shows the reddish color of the deposits from the giant volcanic eruption at the volcano Tvashtar, near the top of the sunlit crescent, as well as the bluish plume itself and the orange glow of the hot lava at its source. The relatively unprocessed image on the left provides the best view of the volcanic glow and the plume deposits, while the version on the right has been brightened to show the much fainter plume, and the Jupiter-lit night side of Io.

    New Horizons' color imaging of Io's sunlit side was generally overexposed because the spacecraft's color camera, the super-sensitive Multispectral Visible Imaging Camera (MVIC), was designed for the much dimmer illumination at Pluto. However, two of MVIC's four color filters, the blue and 'methane' filter (a special filter designed to map methane frost on the surface of Pluto at an infrared wavelength of 0.89 microns), are less sensitive than the others, and thus obtained some well-exposed views of the surface when illumination conditions were favorable. Because only two color filters are used, rather than the usual three, and because one filter uses infrared light, the color is only a rough approximation to what the human eye would see.

    The red color of the Tvashtar plume fallout is typical of Io's largest volcanic plumes, including the previous eruption of Tvashtar seen by the Galileo and Cassini spacecraft in 2000, and the long-lived Pele plume on the opposite side of Io. The color likely results from the creation of reddish three-atom and four-atom sulfur molecules (S3 and S4) from plume gases rich in two-atom sulfur molecules (S2 After a few months or years, the S3 and S4 molecules recombine into the more stable and familiar yellowish form of sulfur consisting of eight-atom molecules (S8), so these red deposits are only seen around recently-active Io

  13. Analysis of FEL optical systems with grazing incidence mirrors

    SciTech Connect

    Knapp, C.E.; Viswanathan, V.K.; Bender, S.C.; Appert, Q.D.; Lawrence, G.; Barnard, C.

    1986-01-01

    The use of grazing incidence optics in resonators alleviates the problem of damage to the optical elements and permits higher powers in cavities of reasonable dimensions for a free electron laser (FEL). The design and manufacture of a grazing incidence beam expander for the Los Alamos FEL mock-up has been completed. In this paper, we describe the analysis of a bare cavity, grazing incidence optical beam expander for an FEL system. Since the existing geometrical and physical optics codes were inadequate for such an analysis, the GLAD code was modified to include global coordinates, exact conic representation, raytracing, and exact aberration features to determine the alignment sensitivities of laser resonators. A resonator cavity has been manufactured and experimentally setup in the Optical Evaluation Laboratory at Los Alamos. Calculated performance is compared with the laboratory measurements obtained so far.

  14. Characterization of a Grazing-Incidence Dye laser

    NASA Astrophysics Data System (ADS)

    Smith, R. Seth

    2010-10-01

    The grazing-incidence dye laser remains a versatile device for generating tunable laser radiation for a variety of scientific applications. A homebuilt grazing incidence dye laser was constructed at Francis Marion University. This laser is pumped by the second harmonic output from a Continuum Surelite I YAG laser. A small percentage of the pump radiation is coupled into the dye laser. A cylinder lens brings this light to a tight focus on the laser dye. The resulting fluorescence is dispersed by a diffraction grating that is held at grazing-incidence. A portion of this light is reflected by a tuning mirror and is directed back into the active medium for amplification. The output wavelength is controlled by scanning the tuning mirror. The performance of this dye laser was analyzed. The results will be presented and discussed.

  15. Wildfire: It's Economic Impact on Grazing Livestock in Northern Nevada

    NASA Astrophysics Data System (ADS)

    Honeycutt, S.

    2015-12-01

    As the climate changes and Nevada experiences long severe drought, a key understanding of the economic impacts of wildfire on grazing livestock is essential in the assurance of livestock production in future management of Nevada's rangeland. The focus of this research is to determine the economic impact in the reduction of rangeland available for livestock grazing due to wildfires. The datasets utilized in this research are from 2007 & 2012 and include Bureau of Land Management wildfire, grazing allotments and herd management area geospatial data along with USDA Census of Agriculture, Inventory & Sales Information for cattle & calves, sheep & lambs, and goats. Presented in the results will be the direct, indirect, and induced economic effects of wildfires on rangeland production.

  16. Changes in vegetation and grazing capacity following honey mesquite control

    USGS Publications Warehouse

    McDaniel, Kirk C.; Brock, John H.; Haas, Robert H.

    1982-01-01

    Honey mesquite kill and suppression, vegetation response, and changes in grazing use and capacity were evaluated following brush control in north-central Texas. Tree grubbing was most effective for eliminating honey mesquite, but because of soil and plant damage the treatment did not increase grazing capacity or improve range condition compared to nontreated rangeland. Aerial application of 2,4,5-T + picloram was more effective in klllmg and defoliating honey mesquite than 2,4,5-T alone, but both treatments significantly increased forage production. The 2,4,5-T + picloram and 2,4,5-T sprays provided a 7 to 16% increase in grazing capacity over a 4-year period on light and heavy honey mesquite infested pastures, respectively.

  17. Grazing increases the concentration of CLA in dairy cow milka.

    PubMed

    Lahlou, M N; Kanneganti, R; Massingill, L J; Broderick, G A; Park, Y; Pariza, M W; Ferguson, J D; Wu, Z

    2014-07-01

    An experiment was conducted to examine whether increased CLA in milk of dairy cows fed fresh pasture compared with alfalfa and corn silages was because of ruminal or endogenous synthesis. Eight Holsteins were fed a total mixed ration using alfalfa and corn silages as the forage source in confinement or grazed in a replicated crossover design. The proportion of total fatty acids as CLA (primarily c9, t11-18:2) in g/100 g was 0.44 v. 0.28 in ruminal digesta, 0.89 v. 0.53 in omasal digesta and 0.71 v. 1.06 in milk during confinement feeding and grazing, respectively. Blood plasma CLA was 0.54 v. 1.05 mg/l for the two treatments, respectively. The increased concentration of CLA in milk with grazing likely resulted from increased synthesis through desaturation of t11-18:1 in the mammary gland.

  18. Microzooplankton grazing in the Eastern Bering Sea in summer

    NASA Astrophysics Data System (ADS)

    Stoecker, Diane K.; Weigel, Alison; Goes, Joaquim I.

    2014-11-01

    Dilution experiments to estimate microzooplankton grazing on phytoplankton were conducted during the summers of 2008, 2009, and 2010 in the Eastern Bering Sea as part of the BEST-BSIERP integrated ecosystem project. All three summers followed cold springs in the Bering Sea. Average microzooplankton grazing coefficients were relatively similar among regions, ranging from 0.16 to 0.34 d-1 in simulated in situ incubations with mixed-layer water collected from the depth of the 55% Io isolume. In Off Shelf and Outer Shelf domains, microzooplankton consumed 67-78% of phytoplankton daily growth but in the Middle and Inner Shelf domains, microzooplankton grazing exceeded phytoplankton daily growth. Regional estimates of microzooplankton ingestion of phytoplankton carbon ranged from 4.4 to 11.0 μg C d-1, with highest ingestion in the Off Shelf, Outer Shelf, and Alaska Peninsula regions and, lower ingestion in the Middle Shelf and Inner Shelf regions. On the northern Middle Shelf, a deep chlorophyll maximum (DCM) occurred at most stations. Grazing coefficients in the DCM were similar in magnitude to coefficients in the corresponding mixed layer. However, because of the higher phytoplankton biomass in the DCM, estimated microzooplankton ingestion and secondary production per liter were higher in the DCM than in the mixed layer. Measurements of photosynthetic quantum yields (Fv/Fm) in whole seawater and diluted treatments indicated that with some plankton assemblages, dilution had a negative effect on phytoplankton physiology and could have compromised their growth rates. This could have also resulted in an underestimation of microzooplankton grazing. Nevertheless, it is clear that microzooplankton grazing consumed most of the phytoplankton production in summer, and that microzooplankton were an important link in food webs supporting larger zooplankton and in carbon flow in the Eastern Bering Sea.

  19. [Effect of grazing on sandy grassland ecosystem in Inner Mongolia].

    PubMed

    Zhao, Halin; Zhang, Tonghui; Zhao, Xueyong; Zhou, Ruilian

    2004-03-01

    This experiment was carried out for 5 years in Horqin sandy land, lnner Mongolia, which had 4 treatments: Non-grazing (NG), light grazing (LG), moderate grazing (MG) and over grazing (OG). The results showed that different grazing intensities resulted in different development trend of the pasture ecosystem, of which, the injury of OG on pasture ecosystem was very great. The plant diversity, vegetation coverage, plant height and primary productivity under continuous overgrazing for 5 year were 87.9%, 82.1%, 94.0% and 57.0%, respectively, lower than those in NG. The biomass on the OG pasture was only 2.1% of NG, and the contents of soil clay, C and N as well as the quantities of soil microbes and small animals in OG were respectively 6.0%, 31.9%, 25.0%, 95.0% and 75.9% lower than those in NG, but the soil hardness was raised by 274.0%. Especially, the secondary productivity of the pasture became negative from the third year, and the productive foundation of the pasture ecosystem was completely destroyed. Non-grazing was beneficial to pasture, and enclosure caused an increase in vegetation coverage, plant height and primary productivity. The vegetation coverage, plant height and soil status in LG and MG were not as good as those in NG, but were stable and didn't show worsening trend. Based on the above results, it's considered that on the sandy pasture in the semi-arid area of Inner Mongolia, the rational grass utilization ratio is 45%-50%, and the suitable loading capacity is 3-4 sheep unit.hm-2.

  20. High motility reduces grazing mortality of planktonic bacteria.

    PubMed

    Matz, Carsten; Jürgens, Klaus

    2005-02-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 microm s(-1) as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 microm s(-1)) and a highly motile strain (>45 microm s(-1)) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 microm(3). Grazing mortality was lowest for cells of >0.5 microm(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (< or =0.1 microm(3), >50 microm s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing.

  1. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands

    Treesearch

    J.D. Reeder; G.E. Schuman

    2001-01-01

    We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in...

  2. Red blood cell production

    MedlinePlus

    ... to one part of the body or another. Red blood cells are an important element of blood. Their job ... is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of ...

  3. Flow visualization in long neck Helmholtz resonators with grazing flow

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Rice, E. J.

    1976-01-01

    Both oscillating and steady flows were applied to a single plexiglass resonator cavity with colored dyes injected in both the orifice and grazing flow field to record the motion of the fluid. For oscillatory flow, the instantaneous dye streamlines were similar for both the short and long-neck orifices. The orifice flow blockage appears to be independent of orifice length for a fixed amplitude of flow oscillation and magnitude of the grazing flow. The steady flow dye studies showed that the acoustic and steady flow resistances do not necessarily correspond for long neck orifices.

  4. Absolute calibration in grazing incidence interferometry via rotational averaging

    SciTech Connect

    Mantel, Klaus; Lamprecht, Juergen; Lindlein, Norbert; Schwider, Johannes

    2006-06-01

    Interferometry in grazing incidence can be used to test cylindrical mantle surfaces. The absolute accuracy of the resulting surface profiles is limited by systematic wavefront aberrations caused in the interferometer, in particular due to an inversion of the test wavefront in an interferometer using diffractive beam splitters. For cylindrical specimens, a calibration method using four positions has therefore been investigated. This test is combined with another method of optical metrology: the rotational averaging procedure. The implementation for grazing incidence is described and measurement results for hollow cylinders are presented. The gain in accuracy is demonstrated.

  5. Absolute calibration in grazing incidence interferometry via rotational averaging.

    PubMed

    Mantel, Klaus; Lamprecht, Jürgen; Lindlein, Norbert; Schwider, Johannes

    2006-06-01

    Interferometry in grazing incidence can be used to test cylindrical mantle surfaces. The absolute accuracy of the resulting surface profiles is limited by systematic wavefront aberrations caused in the interferometer, in particular due to an inversion of the test wavefront in an interferometer using diffractive beam splitters. For cylindrical specimens, a calibration method using four positions has therefore been investigated. This test is combined with another method of optical metrology: the rotational averaging procedure. The implementation for grazing incidence is described and measurement results for hollow cylinders are presented. The gain in accuracy is demonstrated.

  6. A better trihedral corner reflector for low grazing angles

    NASA Astrophysics Data System (ADS)

    Doerry, A. W.; Brock, B. C.

    2012-06-01

    Trihedral corner reflectors are the preferred canonical target for SAR performance evaluation for many radar development programs. The conventional trihedrals have problems with substantially reduced Radar Cross Section (RCS) at low grazing angles, unless they are tilted forward, but in which case other problems arise mainly due to multipath effects. Consequently there is a need for better low grazing angle performance for trihedrals. This is facilitated by extending the bottom plate of the trihedral reflector. A relevant analysis of RCS for an infinite ground plate is presented. Practical aspects are also discussed.

  7. Grazing incidence ion erosion in the presence of adsorbates

    NASA Astrophysics Data System (ADS)

    Redinger, A.; Rosandi, Y.; Urbassek, H. M.; Michely, T.

    2009-06-01

    The effect of a background pressure of adsorbable species on sputtering and surface damage in grazing incidence ion erosion of Pt(111) is investigated by scanning tunneling microscopy and molecular dynamics simulations. The background pressure implies a partial surface coverage with adsorbates, which in turn causes an enhancement of the erosion rate by a factor of up to 40 compared to the clean case. Partial pressures of molecular oxygen and carbon monoxide were maintained during ion erosion with 5 keV Ar+ for various grazing angles between 81° and 87° and temperatures ranging from 400 to 550 K.

  8. Development of a temporally and spatially resolved grazing incidence spectrometer

    SciTech Connect

    Dietrich, D.D.; Fortner, R.J.; Price, D.F.; Stewart, R.E.; Gilman, C.; Helava, H.

    1980-01-01

    The design considerations are presented for a grazing incidence spectrometer which will resolve both temporally and spatially the emission from a wide variety of plasmas. The basis of the design involves use of microchannel plates (MCPs) which are curved to conform to the Rowland circle of the spectrometer. The spectra are obtained when the anode is properly biased. The use of multiple anodes allows gating and with appropriate delays results in sequential time resolution of a few nanoseconds. Simultaneous gating of the anodes with spatial resolution of < 100..mu.. for any given time frame can also be obtained. The efficiency of this spectrometer is also compared with conventional grazing incidence spectrometers.

  9. Preliminary results from a shallow water benthic grazing study

    USGS Publications Warehouse

    Jones, N.L.; Monismith, Stephen G.; Thompson, Janet K.

    2005-01-01

    Despite great improvements in our knowledge on the effects of benthic grazers on seston concentrations in water columns, the effects of different hydrodynamic conditions on grazing rates has not been formulated. This makes it difficult to assess the system-wide effect of the benthic ecosystem on phytoplankton concentrations. Furthermore, it affects our ability to predict the potential success of a benthic species, such as the invasive clams Corbicula fluminea and Potamocorbula amurensis. This paper presents the preliminary results of a control volume approach to elucidate the effect of different hydrodynamic conditions on the grazing rates of Corbicula fluminea.

  10. Effects of grazing on grassland soil carbon: a global review.

    PubMed

    McSherry, Megan E; Ritchie, Mark E

    2013-05-01

    Soils of grasslands represent a large potential reservoir for storing CO2 , but this potential likely depends on how grasslands are managed for large mammal grazing. Previous studies found both strong positive and negative grazing effects on soil organic carbon (SOC) but explanations for this variation are poorly developed. Expanding on previous reviews, we performed a multifactorial meta-analysis of grazer effects on SOC density on 47 independent experimental contrasts from 17 studies. We explicitly tested hypotheses that grazer effects would shift from negative to positive with decreasing precipitation, increasing fineness of soil texture, transition from dominant grass species with C3 to C4 photosynthesis, and decreasing grazing intensity, after controlling for study duration and sampling depth. The six variables of soil texture, precipitation, grass type, grazing intensity, study duration, and sampling depth explained 85% of a large variation (±150 g m(-2)  yr(-1) ) in grazing effects, and the best model included significant interactions between precipitation and soil texture (P = 0.002), grass type, and grazing intensity (P = 0.012), and study duration and soil sampling depth (P = 0.020). Specifically, an increase in mean annual precipitation of 600 mm resulted in a 24% decrease in grazer effect size on finer textured soils, while on sandy soils the same increase in precipitation produced a 22% increase in grazer effect on SOC. Increasing grazing intensity increased SOC by 6-7% on C4 -dominated and C4 -C3 mixed grasslands, but decreased SOC by an average 18% in C3 -dominated grasslands. We discovered these patterns despite a lack of studies in natural, wildlife-dominated ecosystems, and tropical grasslands. Our results, which suggest a future focus on why C3 vs. C4 -dominated grasslands differ so strongly in their response of SOC to grazing, show that grazer effects on SOC are highly context-specific and imply that grazers in different regions might

  11. Tillage Requirements Of Sweet Corn, Field Pea, and Watermelon Following Stocker Cattle Grazing

    USDA-ARS?s Scientific Manuscript database

    Winter annual grazing combined with vegetable production can potentially improve the sustainability of farming operations, particularly in the Southeast. However, winter grazing creates excessive soil compaction, which can adversely affect yields of subsequent summer crops. We initiated a study to...

  12. Grazing Land Management Strongly Controls Water Quality, Sediment and Channel Dynamics in Tallgrass Prairie Headwater Networks

    NASA Astrophysics Data System (ADS)

    Grudzinski, B. G.; Daniels, M. D.

    2013-12-01

    In the prairie remnants of North America, watershed sediment regimes are heavily influenced by livestock grazing practices. Despite dramatic declines in stream water quality and ecosystem function concomitant with increasing gazing pressures, there have been no studies to quantitatively assess the relationship between various grazing treatments and sediment production in natural grassland ecosystems. In this study, we evaluate suspended sediment transport and channel morphology in the Flint Hills physiographic province using a paired whole-watershed approach, including 2 replicates of high density cattle grazing, 2 replicates of low density cattle grazing, 3 replicates of bison grazing and 3 replicates of no grazing. As expected, results demonstrate that cattle grazing operations increase e-coli, sediment concentrations and increase channel width. However, no significant differences in e-coli, suspended sediment dynamics or channel geomorphology were found between bison grazed and ungrazed watersheds.

  13. 78 FR 32273 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number 1076-0162. This.... Data OMB Control Number: 1076-0162. Title: Navajo Partitioned Lands Grazing Permits, 25 CFR 161. Brief...

  14. 78 FR 15036 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number 1076-0162. This... to do so. III. Data OMB Control Number: 1076-0162. Title: Navajo Partitioned Lands Grazing Permits...

  15. 77 FR 74634 - Okanogan-Wenatchee National Forest, Okanogan County, WA Bannon, Aeneas, Revis, and Tunk Grazing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-17

    ... Grazing Allotments Environmental Impact Statement; Correction AGENCY: Forest Service, USDA. ACTION: Notice..., 2012, concerning requests for comments on the proposed grazing allotments and dates of...

  16. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective.

  17. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes described...

  18. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes described...

  19. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section 166.306 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In consultation...

  20. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes described? Indian...

  1. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes described...

  2. Above- and below-ground grass growth responds to grazing management

    USDA-ARS?s Scientific Manuscript database

    How is grass productivity above- and below-ground affected by grazing at different heights or by leaving different residuals after grazing? A recent study found no simple answer to this question. Meadow fescue and orchardgrass were grazed by Holstein heifers to remove 50 or 100% of above-ground fora...

  3. Prescribed grazing for management of invasive vegetation in a hardwood forest understory

    Treesearch

    Ronald A. Rathfon; Songlin Fei; Jason Tower; Kenneth Andries; Michael. Neary

    2014-01-01

    Land managers considering prescribed grazing (PG) face a lack of information on animal stocking rates, timing of grazing, and duration of grazing to achieve desired conditions in natural ecosystems under invasion stress from a variety of nonnative invasive plant (NNIP) species. In this study we tested PG treatments using goats for reducing NNIP brush species and...

  4. Effects of Timing of Grazing on Arthropod Communities in Semi-Natural Grasslands

    PubMed Central

    Lenoir, Lisette; Lennartsson, Tommy

    2010-01-01

    Arthropod communities were investigated in two Swedish semi-natural grasslands, each subject to two types of grazing regime: conventional grazing from May to September (continuous grazing) and traditional late management from mid-July (late grazing). Pitfall traps were used to investigate abundance of carabids, spiders, and ants over the grazing season. Ant abundance was also measured by mapping nest density during three successive years. Small spiders, carabids and ants (Myrmica spp.) were more abundant in continuous grazing than in late grazing while larger spiders, carabids, and ants (Formica spp.) were more abundant in late grazing. The overall abundance of carabids was higher in continuous grazing in the early summer but higher in late grazing in the late summer. The switch of preference from continuous to late grazing coincided with the time for larvae hibernating species replacing adult hibernating. We discuss possible explanations for the observed responses in terms of effects of grazing season on a number of habitat variables for example temperature, food resources, structure of vegetation, litter layer, competition, and disturbance. PMID:20569138

  5. Sheep grazing effect on dryland soil carbon and nitrogen in the wheat-fallow system

    USDA-ARS?s Scientific Manuscript database

    Weed control by sheep grazing during fallow periods in the dryland wheat-fallow system may influence soil C and N levels. The effects of fallow management for weed control and soil water conservation [sheep grazing (grazing), herbicide application (chemical), and tillage (mechanical)] and cropping s...

  6. Monitoring riparian response to prescription grazing with low-altitude aerial surveys

    USDA-ARS?s Scientific Manuscript database

    Prescription grazing (controlling grazing animals to achieve a specified conservation objective) is a USDA Natural Resources Conservation Service approved practice. But, there is no approved means for assessing the success or failure of extensive-area grazing prescriptions. In 2003 a prescription gr...

  7. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing permit...

  8. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing permit...

  9. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing permit...

  10. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in... 166 of this chapter; and agricultural lands and all other grazing lands shall be leased in accordance...

  11. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in... 166 of this chapter; and agricultural lands and all other grazing lands shall be leased in accordance...

  12. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in... 166 of this chapter; and agricultural lands and all other grazing lands shall be leased in accordance...

  13. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in... 166 of this chapter; and agricultural lands and all other grazing lands shall be leased in accordance...

  14. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in... 166 of this chapter; and agricultural lands and all other grazing lands shall be leased in accordance...

  15. Steers grazing of a rye cover crop influences growth of rye and no-till cotton

    USDA-ARS?s Scientific Manuscript database

    Small grain cover crops offer opportunities for grazing but effects on following row crops are not well understood. From 1999 through 2008, stocker steers sequence grazed small grains in a 2-paddock rye-cotton-wheat-fallow- rye rotation. Treatments imposed on rye included 1) zero-grazing from 1999; ...

  16. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    ERIC Educational Resources Information Center

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

  17. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    ERIC Educational Resources Information Center

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

  18. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply to grazing permits? Navajo Nation laws generally apply to land under the jurisdiction of the Navajo Nation... 25 Indians 1 2010-04-01 2010-04-01 false Do tribal laws apply to grazing permits? 161.100...

  19. Responses of plant communities to grazing in the southwestern United States

    Treesearch

    Daniel G. Milchunas

    2006-01-01

    Grazing by wild and domestic mammals can have small to large effects on plant communities, depending on characteristics of the particular community and of the type and intensity of grazing. The broad objective of this report was to extensively review literature on the effects of grazing on 25 plant communities of the southwestern U.S. in terms of plant species...

  20. The science behind the use of prescribed grazing as a conservation practice

    USDA-ARS?s Scientific Manuscript database

    Conservation Practice Standard 528 of the Natural Resource Conservation Service (NRCS) defines prescribed grazing as “managing the harvest of vegetation with grazing and/or browsing animals”. Prescribed grazing or browsing incorporates a variety of management actions. For the purposes of this presen...

  1. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing permit...

  2. Responses of arthropod fauna assemblages to goat grazing management in northern Spanish heathlands.

    PubMed

    Rosa García, Rocío; Jáuregui, Berta M; García, Urcesino; Osoro, Koldo; Celaya, Rafael

    2009-08-01

    Changes in arthropod fauna assemblages after different goat grazing treatments (breeds and stocking rates) and responses to grazing cessation were studied in a heath-gorse shrubland located in northern Spain. Three treatments (low grazing pressure and high grazing pressure with Cashmere breed and high grazing pressure with local Celtiberic breed) with three replicates were randomly allocated to nine plots. Fauna data were collected three times per year during 3 grazing yr (2003, 2004, and 2005) and three times during 2007, i.e., 2 yr after grazing cessation. Arthropods were collected by 12 pitfall traps per plot, whereas vegetation cover and height were estimated by 100 random contacts per plot. Arthropod community composition was mostly affected by sampling year during the grazing period (between 2003 and 2005) but also between 2005 and 2007 (after cessation). Species composition differed between treatments, although the differences were not attributed to the stocking rates or to the goat breeds along those periods. Differences between treatments remained constant from 2003 to 2005 and between 2005 and 2007. Heather height explained most of the variance in arthropod species data during the last grazing year (2005), whereas heather cover was the most explanatory environmental variable 2 yr after grazing cessation (2007). Grazing effects still remained on both vegetation and fauna 2 yr after grazing cessation.

  3. [Microbial community structure of the alpine meadow under different grazing styles in Naqu prefecture of Tibet].

    PubMed

    Niu, Lei; Liu, Ying-hui; Li, Yue; Ouyang, Sheng-nan

    2015-08-01

    To clarify the effects of grazing styles on the soil microbial community in the alpine meadow, we explored the changes of soil microbial community structure in the alpine meadow located in Naqu district of Tibet Autonomous Region by analyzing the soil chemical properties and phospholipid fatty acids (PLFAs). The results showed that the contents of soil total organic carbon, total phosphate and nitrate nitrogen under the different grazing styles followed the trend of 7-year rest grazing > free grazing > grazing prohibition. Except for the ratio of fungal PLFAs/bacterial PLFAs, total PLFAs, the bacterial PLFAs, the fungal PLFAs, the gram negative bacterial and the gram positive bacterial PLFAs over the different grazing types were in the order of 7-year rest grazing > 5-year grazing prohibition > 7-year and 9-year grazing prohibition. The principal component analysis (PCA) presented that the first principal component (PC1 = 74.6%) was mainly composed of monounsaturated fatty acids, polyunsaturated fatty acids and branched fatty acids, and the second principal component (PC2 = 13.2%) was mainly composed of saturated fatty acids and some monounsaturated fatty acids. Total PLFAs content was significantly positively correlated with microbial biomass carbon content. Compared with grazing prohibition, fallow grazing was best for the alpine meadow in Naqu district, and free grazing with light intensity was good for the alpine meadow.

  4. Cow weights and calf production for pasture 12-C Lehmann lovegrass grazing trials, 1982 to 1993

    Treesearch

    Phil R. Ogden; E. Lamar. Smith

    2003-01-01

    The purpose of the grazing trials described in this paper was to provide information to aid in the development of grazing management strategies where Lehmann lovegrass has become a dominant species. Seven pastures were utilized from 1984 to 1987 for a comparison of four yearlong stocking rates to seasonal grazing rotated through three pastures. A second trial, 1988 to...

  5. Effects of timing of grazing on arthropod communities in semi-natural grasslands.

    PubMed

    Lenoir, Lisette; Lennartsson, Tommy

    2010-01-01

    Arthropod communities were investigated in two Swedish semi-natural grasslands, each subject to two types of grazing regime: conventional grazing from May to September (continuous grazing) and traditional late management from mid-July (late grazing). Pitfall traps were used to investigate abundance of carabids, spiders, and ants over the grazing season. Ant abundance was also measured by mapping nest density during three successive years. Small spiders, carabids and ants (Myrmica spp.) were more abundant in continuous grazing than in late grazing while larger spiders, carabids, and ants (Formica spp.) were more abundant in late grazing. The overall abundance of carabids was higher in continuous grazing in the early summer but higher in late grazing in the late summer. The switch of preference from continuous to late grazing coincided with the time for larvae hibernating species replacing adult hibernating. We discuss possible explanations for the observed responses in terms of effects of grazing season on a number of habitat variables for example temperature, food resources, structure of vegetation, litter layer, competition, and disturbance.

  6. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  7. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  8. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  9. 25 CFR 166.409 - How is my grazing rental payment determined?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How is my grazing rental payment determined? 166.409 Section 166.409 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.409 How is...

  10. 25 CFR 166.413 - To whom are grazing rental payments made?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false To whom are grazing rental payments made? 166.413 Section 166.413 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.413 To whom are...

  11. 25 CFR 166.401 - How does the BIA establish grazing rental rates?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How does the BIA establish grazing rental rates? 166.401 Section 166.401 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination...

  12. 43 CFR 4300.40 - How long can I graze reindeer with my permit?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false How long can I graze reindeer with my...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Conditions of Your Approved Permit § 4300.40 How long can I graze reindeer...

  13. 25 CFR 166.410 - When are grazing rental payments due?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When are grazing rental payments due? 166.410 Section 166.410 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.410 When are...

  14. 25 CFR 166.418 - When is a grazing rental payment late?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is a grazing rental payment late? 166.418 Section 166.418 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.418 When is a...

  15. 25 CFR 166.409 - How is my grazing rental payment determined?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How is my grazing rental payment determined? 166.409 Section 166.409 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.409 How is...

  16. 25 CFR 166.410 - When are grazing rental payments due?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When are grazing rental payments due? 166.410 Section 166.410 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.410 When are...

  17. 43 CFR 2711.1-3 - Sales requiring grazing permit or lease cancellations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Sales requiring grazing permit or lease... POLICY AND MANAGEMENT ACT Sales: Procedures § 2711.1-3 Sales requiring grazing permit or lease cancellations. When lands are identified for disposal and such disposal will preclude livestock grazing,...

  18. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Do tribal laws apply to grazing permits? 161.100 Section... LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply to grazing permits? Navajo Nation laws generally apply to land under the jurisdiction of the Navajo...

  19. 25 CFR 166.413 - To whom are grazing rental payments made?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false To whom are grazing rental payments made? 166.413 Section 166.413 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.413 To whom are...

  20. 25 CFR 166.401 - How does the BIA establish grazing rental rates?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How does the BIA establish grazing rental rates? 166.401 Section 166.401 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination...

  1. 25 CFR 166.418 - When is a grazing rental payment late?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is a grazing rental payment late? 166.418 Section 166.418 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.418 When is a...

  2. Effects of grazing management treatment on grassland plant communities and prairie grouse habitat

    Treesearch

    Llewellyn L. Manske; William T. Barker; Mario E. Biondini

    1988-01-01

    Seasonlong grazing treatments show no benefit to grass basal cover and visual obstruction is not adequate. Pastures with one grazing period in mid season show no positive change in grass basal cover but have better visual obstruction than seasonlong. Deferred grazing decreases basal cover of warm season grasses and visual obstruction reduced to inadequate levels the...

  3. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes...

  4. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section 166.306 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In...

  5. Enhancing Soil Productivity Using a Multi-Crop Rotation and Beef Cattle Grazing

    NASA Astrophysics Data System (ADS)

    Şentürklü, Songül; Landblom, Douglas; Cihacek, Larry; Brevik, Eric

    2016-04-01

    Agricultural production systems that include complimentary plant, soil and animal interaction contribute to sustainability. In sustainable livestock systems integrated with crop production, the soil resource is impacted positively. The goal of this research was to maximize beef cattle and crop economic yield, while improving the soil resource by increasing soil organic matter (SOM) and subsequently seasonal soil nitrogen fertility over a 5-year period (2011-2015). Each experimental crop field used in the study was 1.74 ha. Small-seeded crops were planted using a JD 1590 No-Till drill. Corn (C) and sunflowers (SF) were planted using a JD 7000 No-Till planter. The cropping sequence used in the study was SF, hard red spring wheat (HRSW), fall seeded winter triticale-hairy vetch (T-HV), spring harvested for hay/mid-June seeded 7-species cover crop (CC; SF, Everleaf Oat, Flex Winter Pea, HV, Winfred Forage Rape, Ethiopian Cabbage, Hunter Leaf Turnip), C (85-day var.), and field pea-barley intercrop (PBY). The HRSW and SF were harvested as cash crops and the PBY, C, and CC were harvested by grazing cattle. In the system, yearling beef steers grazed PBY and unharvested C before feedlot entry, and after weaning, gestating cows grazed CC. Seasonal soil nitrogen fertility was measured at 0-15, 15-30, and 30-61 cm depths approximately every two weeks from June to October, 2014. The regression illustrating the relationship between SOM and average seasonal available mineral nitrogen shows that for each percentage increase in SOM there is a corresponding N increase of 1.47 kg/ha. Nitrogen fertilizer applications for the 5-year period of the study were variable; however, the overall trend was for reduced fertilizer requirement as SOM increased. At the same time, grain, oilseed, and annual forage crop yields increased year over year (2011-2015) except for the 2014 crop year, when above average precipitation delayed seeding and early frost killed the C and SF crops prematurely

  6. Estimating carbon fluxes on small rotationally grazed pastures

    USDA-ARS?s Scientific Manuscript database

    Satellite-based Normalized Difference Vegetation Index (NDVI) data have been extensively used for estimating gross primary productivity (GPP) and yield of grazing lands throughout the world. Large-scale estimates of GPP are a necessary component of efforts to monitor the soil carbon balance of grazi...

  7. Post-fire grazing management in the Great Basin

    USDA-ARS?s Scientific Manuscript database

    Increasing wildfire size and frequency in the Great Basin call for post-fire grazing management practices that ensure sagebrush steppe communities are productive and resilient to disturbances such as drought and species invasions. We provide guidelines for maintaining productive sagebrush steppe co...

  8. Stockpiled Prairie Grass For Fall-Grazing Lambs

    USDA-ARS?s Scientific Manuscript database

    New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over 'Matua' under USA growing conditions, but animal performance data is lacking. Therefore, we evaluated performance of lambs grazing fall-stockpiled 'Dixon' prairiegrass on a West Virgin...

  9. Faraday induction when a loop grazes a magnet

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Holub, Eric M.; Roberts, Marc F.; Wasser, Valerie K.

    2016-07-01

    We perform an experiment to detect electromagnetic induction when a magnet and a loop approach each other in grazing motion, oriented parallel to each other and with one magnet pole pointing at the loop. A weak emf is detected with a three-peak structure, which we explain. We also describe how a more complicated structure can arise.

  10. Large animal grazing and temporal patterns in ecosystem services

    USDA-ARS?s Scientific Manuscript database

    The shortgrass steppe ecosystem has a long evolutionary history of large animal grazing by bison, which were replaced by domesticated livestock in the mid 1800s. In addition, this ecosystem is characterized by a semi-arid environment with low annual precipitation amounts, but high inter- and intra-a...

  11. Temperate grass response to extent and timing of grazing

    USDA-ARS?s Scientific Manuscript database

    Considerable differences exist among cool-season grass species in their production potential and response to management variables. We examined the effects of grazing management on forage and root production of two temperate perennial grasses, meadow fescue [Schedonoruspratensis (Huds.) P. Beauv.] an...

  12. Methane emissions measured directly from grazing livestock in New Zealand

    NASA Astrophysics Data System (ADS)

    Lassey, Keith R.; Ulyatt, Marcus J.; Martin, Ross J.; Walker, Carolyn F.; David Shelton, I.

    We report measurements of methane emissions from individual ruminant livestock-both sheep and dairy cows-grazing pasture typical of New Zealand lowlands in the temperate southwest Pacific. These are the first measurements reported from grazing sheep, and among the first from grazing cattle. The measurement technique, developed at Washington State University, enables emission rates to be determined from analyses of "breath" samples collected while grazing. More than 250 measurements of daily methane emission from 50 sheep (8 months old) were made, with flock-mean emission 18.9 ± 0.8 g hd -1 d -1. Although emissions were weakly correlated with feed intake, they represented a 4.6 ± 0.1 % average loss of gross dietary energy. The corresponding mean emission based on 40 measurements of daily emissions from 10 lactating dairy cows was 263 ± 10 g hd -1 d -1, approximately 6.2% of estimated gross energy intake. A notable feature was the large inter-sheep variability in daily methane emission (factor of 1.4 range) that could not be attributed to variable intake. This would appear to suggest an appreciable diversity of methanogenetic response to digestion, and may be significant in the search for strategies to control emissions of this greenhouse gas.

  13. Grazing sericea lespedeza for control of gastrointestinal nematodes in lambs

    USDA-ARS?s Scientific Manuscript database

    Alternatives to chemical dewormers are needed to counter anthelmintic resistance and improve organic management systems. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) compared with grass pastures for control of gastrointestinal nematodes (GIN) in lambs. In Experi...

  14. Sediment dynamics and sources in a grazed hardwood rangeland watershed

    Treesearch

    Melvin R. George; Neil K. McDougald; Kenneth W. Tate; Royce Larsen

    2002-01-01

    From 1994 to 1998 we documented sediment transport dynamics and sources in a 137 ha grazed hardwood rangeland watershed on granitic soils at the San Joaquin Experimental Range in Madera County. Sediment transport for this watershed was determined by measuring total suspended solids, bedload and flow at an H-flume installed in 1994. Sediment movement as bedload is the...

  15. Thermal balance of cattle grazing winter range: model application.

    PubMed

    Keren, E N; Olson, B E

    2006-05-01

    Beef cattle grazing semiarid foothill rangeland of the Northern Rockies during winter may be exposed to cold temperatures and high winds while grazing pastures with low nutritional value. Cattle can physiologically and behaviorally respond to the changing environment to lower their metabolic requirements and reduce the effects of cold exposure. Requirements of grazing cattle may be overpredicted with models developed in controlled settings that do not account for energy-conserving behaviors. We refined a simple thermal balance equation to model heat exchange of free-ranging cattle. We accounted for the complex interactions between animal behavior and the changing natural environment by applying the insulation characteristics of the cattle's tissue and coat to a simple geometric shape of an asymmetric ellipsoid at different orientations to the sun and wind. We compared the model predictions with heat production measured in 3 studies, and in all cases the model predictions were similar to those reported. Model simulations indicate behaviors, such as lying and orientation to the sun, mitigated the effects of extreme weather. For many combinations of winter weather variables, metabolic requirements increased only slightly due to cold exposure of mature beef cattle in a near-maintenance state. The results indicate that solar radiation contributes strongly to the thermal balance of a cow. Thus, previous models that do not account for the irradiative environment may overestimate metabolic requirements of cattle acclimated to grazing winter range.

  16. Manatee grazing impacts on a mixed species seagrass bed

    USGS Publications Warehouse

    Lefebvre, Lynn W.; Provancha, Jane A.; Slone, Daniel H.; Kenworthy, W. Judson

    2017-01-01

    The endangered manatee Trichechus manatus is one of few large grazers in seagrass systems. To assess the long-term impacts of repeated grazing on seagrasses, we selected a study site within Kennedy Space Center in the northern Banana River, Brevard County, Florida, that was typically grazed by large numbers of manatees in spring. Two 13x13 m manatee exclosures and 2 paired open plots of equal size were established at the study site in October 1990. Shoot counts, biomass, and species composition of the co-dominant seagrass species, Syringodium filiforme and Halodule wrightii, were sampled 3 times per year in all 4 plots between October 1990 and October 1994. We used a Bayesian modelling approach, accounting for the influence of depth, to detect treatment (exclosed vs. open) effects. S. filiforme shoot counts, total biomass, and frequency of occurrence significantly increased in the exclosures. By July 1993, mean biomass values in the exclosures (167 g dry wt m-2) greatly exceeded those in the open plots (28 g dry wt m-2). H. wrightii decreased in the exclosures by 1994. Initially, both S. filiforme and H. wrightii responded positively to release from manatee grazing pressure. As S. filiforme continued to become denser in the exclosures, it gradually replaced H. wrightii. Our findings may be helpful to biologists and managers interested in predicting seagrass recovery and manatee carrying capacity of repeatedly grazed seagrass beds in areas of special significance to manatees and seagrass conservation.

  17. The environmental impacts of grazing in dairy production

    USDA-ARS?s Scientific Manuscript database

    Dairy farms impact the environment in a number of ways, all of which are influenced by the choice of including grassland and managed rotational grazing. Because of the diverse environmental impacts of farming and the interactions of these impacts, an experimental comparison of production strategies ...

  18. Grazing can reduce the environmental impact of dairy production systems

    USDA-ARS?s Scientific Manuscript database

    Incorporating managed rotational grazing into a dairy farm can result in an array of environmental consequences. A comprehensive assessment of the environmental impacts of four management scenarios was conducted by simulating a 250 acre dairy farm typical of Pennsylvania with: (1) a confinement fe...

  19. 76 FR 80329 - Information Collection; Grazing Permit Administration Forms

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... forms are: FS-2200-1, Refund, Credit or Transfer Application, collects the following information: Name... on the allotment; number of cattle, horses, or sheep; Period range not used Reason for less use than... following information: Name and address of applicant Type, amount, and location of requested grazing Period...

  20. Design and performance analysis of multilayer nested grazing incidence optics

    NASA Astrophysics Data System (ADS)

    Zuo, Fuchang; Deng, Loulou; Mei, Zhiwu; Li, Liansheng; Lv, Zhengxin

    2014-10-01

    We have developed X-ray grazing incidence optics with a single mirror. Although t can be used to demonstrate and test on the ground to verify the feasibility of X-ray detection system, it is unable to meet the requirements of X-ray pulsar navigation due to small effective area and large mass. There is an urgent need to develop multilayer nested grazing incidence optics, which consists of multilayer mirrors to form a coaxial and confocal system to maximize the use of space and increase the effective area. In this paper, aiming at the future demand of X-ray pulsar navigation, optimization and analysis of nested X-ray grazing incidence optics was carried out, the recurrence relations between the layers of mirrors were derived, reasonable initial structural parameters and stray light reduction method was given, and theoretical effective collection area was calculated. The initial structure and stray light eliminating structure are designed. The optical-mechanical-thermal numerical model was established using optical analysis software and finite element software for stray light analysis, focusing performance analysis, tolerance analysis, and mechanical analysis, providing evidence and guidance for the processing and alignment of nested X-ray grazing incidence optics.

  1. Sound management may sequester methane in grazed rangeland ecosystems

    USDA-ARS?s Scientific Manuscript database

    Considering their contribution to global warming, the sources and sinks of methane (CH4) should be accounted when undertaking a greenhouse gas inventory for grazed rangeland ecosystems. The aim of this study was to evaluate the mitigation potential of current ecological management programs implement...

  2. Multi-fluid MHD model for Sun-grazing comets

    NASA Astrophysics Data System (ADS)

    Jia, Y.-D.; Russell, C. T.; Liu, W.; Gombosi, T. I.

    2013-09-01

    Sun-grazing comets are comets that dive into the lower corona. Recent advances in spacecraft capabilities have enabled us to observe these comets with high resolution both in time and space. These comets exhibit rich tail activity, even multiple tails. This study investigates a collection of these activities, models the cometary plasma with model-generated coronal conditions.

  3. Pasture-scale methane emissions of grazing cattle

    USDA-ARS?s Scientific Manuscript database

    Grazing cattle are mobile point sources of methane and present challenges to quantify emissions using noninterfering micrometeorological methods. Stocking density is low and cattle can bunch up or disperse over a wide area, so knowing cattle locations is critical. The methane concentration downwind ...

  4. Livestock grazing and sage-grouse habitat: impacts and opportunities

    USDA-ARS?s Scientific Manuscript database

    Sage-grouse obtain resources from sagebrush communities for breeding, summer, and winter life stages. Grazing changes the productivity, composition, and structure of herbaceous plants in sagebrush communities, thus directly influencing the productivity of nesting and early brood-rearing habitats. In...

  5. Does livestock grazing influence spatial patterns of woody plant proliferation?

    USDA-ARS?s Scientific Manuscript database

    Patterns of woody plant proliferation in grasslands and savannas influence rates of erosion, spread of disturbance, and nutrient pools.  Spatial pattern is the outcome of plant dispersal, recruitment, competition/facilitation, and disturbance. We quantified effects of livestock grazing, a widely cit...

  6. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If necessary to provide habitat for wild horses or burros, to implement herd management actions, or to protect wild horses or burros, to implement herd management actions, or to protect wild horses or burros from...

  7. Response of mountain meadows to grazing by recreational pack stock

    Treesearch

    David N. Cole; Jan W. van Wagtendonk; Mitchel P. McClaran; Peggy E. Moore; Neil K. McDougald

    2004-01-01

    Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer’s reed grass (...

  8. Effects and interactions of fire, logging, and grazing

    Treesearch

    Deborah M. Finch; Joseph L. Ganey; Wang Yong; Rebecca T. Kimball; Rex Sallabanks

    1997-01-01

    In this chapter, we summarize current knowledge about the effects of fire, logging, and grazing on coniferous forest birds and their habitats. We critically review the results of studies evaluating how these individual factors influence bird numbers, species diversity, nesting success, and habitat use in ponderosa pine forests. Documented and potential interactions...

  9. Polioencephalomalacia in adult sheep grazing pastures with prostrate pigweed

    PubMed Central

    2005-01-01

    Abstract Polioencephalomalacia was diagnosed in 2 animals from different farms. In apparently healthy animals from same farms, fecal thiaminase and a significant reduction in erythrocyte transketolase activity was observed. The presence of thiaminase in Amaranthus blitoides could have contributed to the development of polioencephalomalacia in sheep grazing on natural pastures. PMID:15759830

  10. Grazing on Regeneration Sites Encourages Pine Seedling Growth

    Treesearch

    Raymond D. Ratliff; Renee G. Denton

    1995-01-01

    Effects of season-long, deferred-rotation, and rest-rotation grazing, on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedling growth and herbaceous vegetation control were studied in regeneration sites at Boyd Hill, Modoc National Forest, California. Seedlings were planted in 1989. Pine seedling survival and damage did not differ, but the...

  11. Distribution of cattle grazing in a northeastern Oregon riparian pasture

    USDA-ARS?s Scientific Manuscript database

    Livestock grazing of a northeastern Oregon riparian pasture was monitored using high-frequency GPS tracking of cattle and high-resolution aerial photography. Tracking collars recorded positions, velocity, date, and time at 1-sec intervals. Areas where animals rested and moved were identified and re...

  12. Managing the herbage utilisation and intake by cattle grazing rangelands

    USDA-ARS?s Scientific Manuscript database

    To be able to predict the performance of grazing cattle in extensive rangeland environments, herbage intake is paramount because it quantifies energy intake and performance. Nutrient demand of the animals is the major driver of herbage intake and characteristics of the sward dictate how this demand...

  13. STOCKPILED PRAIRIEGRASS PROVIDES HIGH-QUALITY FALL GRAZING FOR LAMBS

    USDA-ARS?s Scientific Manuscript database

    New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over ‘Matua’ under USA growing conditions, but animal performance data is lacking. We evaluated performance of lambs grazing stockpiled ‘Dixon’ prairiegrass on West Virginia hill pasture in...

  14. Getting more information from your grazing research beyond cattle performance

    USDA-ARS?s Scientific Manuscript database

    Research examining the nutrition of grazing ungulates can be a rewarding career, however it poses many challenges. This type of science requires the scientist to make many assumptions, deal with numerous variables across a landscape, and requires careful planning to manage these unknowns and produc...

  15. Difficulties associated with predicting forage intake by grazing beef cows

    USDA-ARS?s Scientific Manuscript database

    The current National Research Council (NRC) model is based on a single equation that relates dry matter intake (DMI) to metabolic size and net energy density of the diet offered and was a significant improvement over previous models. However, observed DMI by grazing animals can be conceptualized by...

  16. Phytoplankton growth and microzooplankton grazing in the subtropical Northeast Atlantic.

    PubMed

    Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo

    2013-01-01

    Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11-1.60 d(-1)), especially in the case of the large fraction. Grazing rates were also high (0.15-1.29 d(-1)), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres.

  17. Consequences of prescribed fire and grazing on grassland ant communities.

    PubMed

    Underwood, Emma C; Christian, Caroline E

    2009-04-01

    Prescribed fire and livestock grazing are used for the management and restoration of native grasslands the world over; however, the effects of these management techniques on ant communities are unclear. We examined the response of ants to these disturbances in grasslands in northern California. Twenty-four 30 by 30 m plots were established across two sites that received one of four treatments: grazing, fire, grazing and fire, or no treatment. Ants were censused using 240 pitfall traps with one preburn and two postburn samples (14 d and 1 yr after burning). We analyzed ant abundance using broadly defined groups based on feeding habit and/or habitat use and detected no grazing effect but a significant fire effect that differed by group. Immediate postfire sampling showed an increase in cryptic species (particularly Brachymyrmex depilis). One year after the fire, no response was detected for cryptic species, but burned plots had greater abundance of seed harvesters. Analysis of vegetation showed burned plots had significantly greater forb cover, which might have provided greater food resources, and also lower biomass, which might have facilitated foraging. Understanding the effects of these management tools on ant abundance complements our understanding of their effect on vegetation and assists conservation practitioners effectively manage grassland ecosystems both in California and beyond.

  18. Cyclic Sommerfeld resonances in nanorods at grazing incidences.

    PubMed

    Feng, Simin; Halterman, Klaus; Overfelt, Pamela L; Bowling, Donald

    2009-10-26

    We investigate electromagnetic scattering from nanoscale wires and reveal the emergence of a family of exotic resonances for source waves close to grazing incidence. These grazing resonances have a much higher Q-bandwidth product and thus, a much higher Q factor and broader bandwidth than the pure plasmonic resonances found in metal nanowires. Furthermore, these grazing resonances are much less susceptible to material losses than surface plasmon resonances. Contrary to the process of exciting surface plasmon resonances, these grazing resonances can arise in both dielectric and metallic nanowires and appear near to the cutoff wavelength of the circular waveguide. This peculiar resonance effect originates from the excitation of long range guided surface waves through the interplay of coherently scattered continuum modes coupled with first-order azimuthal propagating modes of the cylindrical nanowire. These first-order cyclic Sommerfeld waves and associated cyclic Sommerfeld resonances revealed here opens up the possibility of an alternative scheme of enhanced fields with a better merit (higher Q-bandwidth product and lower loss) than conventional surface plasmon resonances in the nano-regime. This nanowire resonance phenomenon can be utilized in broad scientific areas, including: metamaterial designs, nanophotonic integration, nanoantennas, and nanosensors.

  19. ANT COMMUNITIES AND LIVESTOCK GRAZING IN THE GREAT BASIN, USA

    EPA Science Inventory

    The objectives of this study were to determine if metrics for ant species assemblages can be used as indicators of rangeland condition, and to determine the influence of vegetation and ground cover variables, factors often influenced by livestock grazing, on ant communities. The ...

  20. Butterfly responses to prairie restoration through fire and grazing

    USGS Publications Warehouse

    Vogel, Jennifer A.; Debinski, Diane M.; Koford, Rolf R.; Miller, J.R.

    2007-01-01

    The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds. ?? 2007 Elsevier Ltd. All rights reserved.

  1. Phanerozoic stromatolites: noncompetitive ecologic restriction by grazing and burrowing animals.

    PubMed

    Garrett, P

    1970-07-10

    The abundance of stromatolites (algal laminated sedimentary structures) in the Precambrian followed by a decline in the Phanerozoic is explained by the evolution and diversification during the Phanerozoic of grazing animals which feed on surface algal mats and of burrowing animals which destroy sedimentary laminations.

  2. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If necessary to provide habitat for wild horses or burros, to implement herd management actions, or to protect...

  3. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If necessary to provide habitat for wild horses or burros, to implement herd management actions, or to protect...

  4. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If necessary to provide habitat for wild horses or burros, to implement herd management actions, or to protect...

  5. Challenges to Predicting Productivity of Grazing Ruminants. Where to now?

    USDA-ARS?s Scientific Manuscript database

    The Fourth Grazing Livestock Nutrition Conference was convened at Estes Park July 9 and 10.There were over 28 poster presentations and 12 conference papers presented. The papers were organized in 6 topical sessions ranging from microbiology to supplementation. The first session covered the potential...

  6. Analysis of a new class of grazing incidence spectroscopic telescope

    NASA Technical Reports Server (NTRS)

    Green, J. C.; Bowyer, S.

    1986-01-01

    The throughput and imaging properties of one of a new class of grazing incidence spectroscopic telescope are examined with a Monte Carlo ray tracing technique. The results are compared with Wolter Schwarzschild type II telescopes of similar size. The image quality of this telescope is comparable, and the control of the off-axis light is superior to the Wolter Schwarzschild design.

  7. Crassostrea virginica grazing on toxic and non-toxic diatoms.

    PubMed

    Thessen, A E; Soniat, T M; Dortch, Q; Doucette, G J

    2010-01-01

    Despite high abundances of toxic Pseudo-nitzschia spp. over Louisiana oyster beds (Crassostrea virginica; eastern oyster) there have been no documented cases of amnesic shellfish poisoning (ASP) in the state. Two possible explanations are that oysters do not readily feed on long pointed chains of Pseudo-nitzschia cells or they discriminate against toxic cells while grazing. To test these hypotheses, short-term grazing experiments were conducted with several diatoms, including the domoic acid (DA)-producing Pseudo-nitzschia multiseries (1.31+/-0.057 pg DA cell(-1)) and the non-toxic Pseudo-nitzschia delicatissima, Thalassiosira weissflogii, and Ditylum brightwellii. Grazing rates on the small centric species T. weissflogii were significantly higher than on the larger and pointier D. brightwellii and either Pseudo-nitzschia species. Grazing on toxic P. multiseries and non-toxic P. delicatissima was not significantly different. Pseudofeces production was higher and feces production was occasionally lower in oysters fed Pseudo-nitzschia spp. than in oysters fed the other two diatoms. Our data demonstrate lower filtration rates of C. virginica on Pseudo-nitzschia spp. relative to the other diatoms tested and comparable filtration on toxic and non-toxic Pseudo-nitzschia spp. These findings suggest that eastern oysters do not discriminate amongst food types due to DA content.

  8. ANT COMMUNITIES AND LIVESTOCK GRAZING IN THE GREAT BASIN, USA

    EPA Science Inventory

    The objectives of this study were to determine if metrics for ant species assemblages can be used as indicators of rangeland condition, and to determine the influence of vegetation and ground cover variables, factors often influenced by livestock grazing, on ant communities. The ...

  9. Evaluation of fodder production systems for grazing dairy farms

    USDA-ARS?s Scientific Manuscript database

    Sprouted grains have gained renewed interest among grazing dairy farmers in response to high grain prices, grain scarcity (in the organic dairy sector) and challenges in producing high-quality forages. This interest has been spurred by high-profile advertising by companies selling the systems, as we...

  10. Hydrologic variability enhances stream biofilm grazing by invertebrates

    NASA Astrophysics Data System (ADS)

    Ceola, S.; Hödl, I.; Adlboller, M.; Singer, G.; Bertuzzo, E.; Mari, L.; Botter, G.; Battin, T. J.; Gatto, M.; Rinaldo, A.

    2012-12-01

    The temporal variability of streamflows is a key feature structuring and controlling ecological communities and ecosystem processes. The magnitude, frequency and predictability of streamflows, and thus of velocity and near-bed shear stress fields, control structure and function of benthic invertebrates and biofilms - attached and matrix-enclosed microbial communities at the base of the food chain. Although alterations of streamflow regime due to climate change, habitat fragmentation or other anthropogenic factors are ubiquitous, their ecological implications remain poorly understood. Here, by experimenting with two contrasting flow regimes in stream microcosms, we show how flow variability affects invertebrate grazing of phototrophic biofilms (i.e. periphyton). In both flow regimes, we manipulated light availability as a key control on biofilm algal productivity and grazer activity, thereby allowing the test of flow regime effects across various biofilm biomass to grazing activity ratios. Average grazing rates were significantly enhanced under variable flow conditions and highest at intermediate light availability. Our results suggest that stochastic flow regime offers increased opportunity for grazing under more favorable shear stress conditions, with implications for trophic carbon transfer in stream food webs.

  11. Dutchwoman Butte revisited: Examining paradigms for livestock grazing exclusion

    Treesearch

    J. Sprinkle; M. Holder; C. Erickson; A. Medina; D. Robinett; G. Ruyle; J. Maynard; S. Tuttle; Jr. J. Hays; W. Meyer; S. Stratton; A. Rogstad; K. Eldredge; J. Harris; L. Howery; W. Sprinkle

    2006-01-01

    In 2000, a collaborative rangeland monitoring program was established with the University of Arizona, Gila County Cattlegrowers, and the Tonto National Forest. Dutchwoman Butte (DWB) is an isolated, ungrazed 40 ha mesa with relict vegetation. Our objective was to contrast the vegetation of DWB to that of a grazed site, Whiskey tank (WT), across multiple years (2001,...

  12. Grazing Behavior of Heifers Measured by Handheld GPS

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to assess how previous grazing experience affects animal movement on pasture. Portable GPS units were used to monitor movements of 32 Holstein (n=21) and Holstein-Jersey (n=11) yearlings. Total distance walked was measured and analyzed as a randomized complete block e...

  13. Grazing and Land Management Strategies for Hardwood Rangelands

    Treesearch

    Melvin R. George

    1991-01-01

    Annual rangelands produce 84 percent of California's range forage which are used all year by sedentary ranching operations and seasonally by migratory operations. Environmental policy, energy and water costs may reduce traditional summer forage sources, resulting in increased grazing pressure on hardwood and annual rangelands. However, the landowner's...

  14. Cultivar Preference of Lambs Grazing Forage Chicory in Ohio

    USDA-ARS?s Scientific Manuscript database

    This project compared grazing preferences of lambs between seven cultivars of forage chicory (Cichorium intybus L.). This on-farm trial was conducted in central Ohio (40.53 degrees N, 82.46 degrees W, 1089 ft above sea level). The chicory was established by using conventional tillage in Bogart Silt...

  15. Cattle as ecosystem engineers: New grazing management enhances rangeland biodiversity

    USDA-ARS?s Scientific Manuscript database

    A confluence of factors has shaped the composition and structure of vegetation on rangelands in the American West. These factors include climate, soils, topography, history of grazing and fire (both wildfire and prescribed fire) as well as legacy effects from prior land management practices. Despite...

  16. Phytoplankton Growth and Microzooplankton Grazing in the Subtropical Northeast Atlantic

    PubMed Central

    Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo

    2013-01-01

    Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2–5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11–1.60 d−1), especially in the case of the large fraction. Grazing rates were also high (0.15–1.29 d−1), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres. PMID:23935946

  17. Astaxanthin production in marine pelagic copepods grazing on two different phytoplankton diets

    NASA Astrophysics Data System (ADS)

    Van Nieuwerburgh, Lies; Wänstrand, Ingrid; Liu, Jianguo; Snoeijs, Pauli

    2005-02-01

    The red carotenoid astaxanthin is a powerful natural antioxidant of great importance in aquatic food webs where it is abundant in eggs and body tissues of fish and crustaceans. Little is known about the impact of the phytoplankton diet on astaxanthin production in copepods, its major pelagic producers. We followed the transfer of carotenoids from phytoplankton to copepods in a mesocosm experiment on the northern Atlantic coast (Norway) and recorded the astaxanthin production in copepods. Wild copepods grazed on nutrient-manipulated phytoplankton blooms, which differed in community composition and nutrient status (nitrogen or silicate limitation). The copepod pigments consisted mainly of free astaxanthin and mono- and diesters of astaxanthin. We found no significant difference in astaxanthin production per copepod individual or per unit C depending on the phytoplankton community. However, in the mesocosms astaxanthin per unit C decreased compared with natural levels, probably through a lower demand for photoprotection by the copepods in the dense phytoplankton blooms. The total astaxanthin production per litre was higher in the silicate-limited mesocosms through increased copepod density. Pigment ratio comparisons suggested that the copepod diet here consisted more of diatoms than in the nitrogen-limited mesocosms. Silicate-saturated diatoms were less grazed, possibly because they could invest more in defence mechanisms against their predators. Our study suggests that the production of astaxanthin in aquatic systems can be affected by changes in nutrient dynamics mediated by phytoplankton community composition and copepod population growth. This bottom-up force may have implications for antioxidant protection at higher trophic levels in the food web.

  18. Preliminary investigation of the reststrahlen phenomenology at low-grazing angles

    NASA Astrophysics Data System (ADS)

    Harr, Richard; Polcha, Michael

    2005-06-01

    Detection of buried and flush buried landmines has been dangerous and time consuming for both military and humanitarian de-mining personnel throughout the world. In an effort to make the process safer, faster, and more reliable, scientists have successfully employed Ground Penetrating Radar (GPR) systems in nadir and near nadir viewing angles. Leveraging this successful technology, Forward-Looking Ground Penetrating Radar (FLGPR) technology, using low grazing angles, is being developed which promises to provide an increase in detection stand-off distance thereby increasing safety of personnel during land-based mine detection efforts. However, the application of GPR for the detection of buried plastic mines has been problematic, research has begun to exploit the comination of broadband and hyper-spectral passive electro-optical technologies with GPR technologies. One such embodiment is to use Forward Looking InfraRed (FLIR) technology with the intention to augment the capability of, and overcome limitations inherent to, current FLGPR technology. The emphasis in using FLIR is to understand and exploit specific spectral features which are complementary fo FLGPR and exhibited by buried metal and plastic mine targets. One spectral feature being investigated is the resstrahlen emission which results when soil is excavated or disturbed. This paper is a preliminary investigation of the performance of a vehicle based FLIR camera system for detecting resstrahlen emissions from disturbed soils. Specifically, this paper will examine the robustness of the resstrahlen feature in a forward-looking low grazing angle application. The data presented in this paper was collected at an eastern US Army testing site over targets deployed in soils which had been disturbed from one day before the start of the collection.

  19. Effects of shade on welfare and meat quality of grazing sheep under high ambient temperature.

    PubMed

    Liu, H W; Cao, Y; Zhou, D W

    2012-12-01

    This study was conducted to evaluate the effects of providing shade on growth performance, welfare, and meat quality of grazing sheep under high ambient temperature. A total of 120 healthy male Ujumqin wool sheep (a local breed; BW = 18.7 ± 1.27 kg; 14 wk old) were randomly and equally divided into shaded and unshaded treatments with 3 pens per treatment. Sheep were grazed on an unshaded pastureland from 0600 to 1000 h and 1400 to 1800 h. During other times, sheep were confined in shaded or unshaded pens. Body weight was recorded on d 1 and 42 of the experiment. Rectal temperature and respiration rate were recorded on d 7, 14, 21, 28, 35, and 42. At end of the trial, sheep were blood sampled and slaughtered to collect meat samples. Respiration rate was greater (P < 0.05) in the unshaded sheep than shaded sheep on d 14, 21, 28, 35, and 42 of the trial whereas no significant differences were found on d 7. Moreover, no differences were observed in final BW, ADG, or rectal temperature throughout the trial. The pH at 24 h postmortem (pH(24)) and cooking loss were greater (P < 0.01) in unshaded than shaded sheep. On the contrary, lightness (L*), redness (a*) and yellowness (b*) values at 24 h postmortem were lower (P < 0.05) in unshaded versus shaded sheep. The sheep in the unshaded group had a greater (P < 0.05) cortisol concentration compared with the shaded group. Sheep in the shaded group had lower creatine kinase activity (P < 0.01) as well as observed for glucose (P < 0.05), triiodothyronine (P < 0.01), and thyroxine (P < 0.05) concentrations and white blood cell count (P < 0.05). Compared with the unshaded group, sheep in the shaded group had a greater lymphocytes (LYM) count (P < 0.05). In contrast, the opposite was true for neutrophils (NEU) count (P < 0.01) and NEU:LYM ratio (P < 0.01). In conclusion, the shade cloth, although not enhancing ADG, improved meat quality traits and certain stress parameters in grazing sheep reared under high ambient temperature.

  20. Impact of grazing management with large herbivores on forest ground flora and bramble understorey

    NASA Astrophysics Data System (ADS)

    Van Uytvanck, Jan; Hoffmann, Maurice

    2009-07-01

    We investigated whether grazing management with large herbivores is appropriate to reduce expanding bramble ( Rubus sp.) in an ancient forest in Flanders (N. Belgium). We further studied interaction effects of four years (all year-round) grazing and Rubus cover on the presence, cover, and flowering of five forest ground flora species (unpalatable: Anemone nemorosa and Primula elatior; palatable: Hyacinthoides non-scripta, Vinca minor and Hedera helix). We collected data on eight transects and in 412 plots in adjacent grazed and ungrazed forest and used baseline datasets of 1996 and 2002 in the same area (i.e. before grazing). In a field experiment, we simulated grazing (by clipping) and trampling (by pressing a weight) in eight homogeneous A. nemorosa vegetation stands. Large Rubus thickets had a clear negative impact on cover and flowering of A. nemorosa due to competition for light. Four years of cattle grazing reduced bramble cover by more than 50%, but then the limiting factor for A. nemorosa cover and flowering shifted to trampling damage. We also found lower cover and flowering of H. non-scripta in grazed plots, as a consequence of direct grazing. The evergreen species V. minor and H. helix totally disappeared from the grazed forest. Simulated once-only effects of grazing and trampling had a small and short term negative impact on cover of A. nemorosa, but flowering was strongly reduced. Grazing reduced biomass with 25-30% in the following years. Year-round grazing with large herbivores is an appropriate measure for bramble control in forests, but negative effects on ground flora are possible if grazing pressure is high. A low or moderate grazing pressure (<0.25 animal units ha -1 y -1) should be maintained in landscape mosaics with grassland and forest; or intermittent periods of non-grazing should be provided to maintain forest ground flora diversity.

  1. Vegetation responses to the first 20 years of cattle grazing in an Australian desert.

    PubMed

    Fensham, R J; Fairfax, R J; Dwyer, J M

    2010-03-01

    Existing theoretical frameworks suggest three predictions relevant to grazing effects in Australian aridlands: grazing has a negative but moderate effect on plant species richness; a separate "state" resulting from degradation caused by extreme grazing will be evident; some plant species will have a strong association with grazing relief refuges that have only ever been subject to light grazing. These predictions were examined in the dune swales of an Australian desert, with data on herbaceous species collected along transects up to 14 km from artificial water points between four and 33 years old. A cumulative grazing index was constructed utilizing both the spatial occupation patterns of cattle and the length of exposure. Despite restricting sampling to a narrow habitat, silt/clay content and soil pH influence floristic patterns independent of grazing. The analysis of quadrat data in relation to grazing revealed almost no patterns in plant cover, species richness (at two different scales), or abundance across plant life-form groups. Five species had an increasing response, and seven a decreasing response, while the only species restricted to areas of extremely low grazing pressure was sufficiently rare that it could have occurred there by chance. The dominant annual grass, the most common shrub, and a perennial tussock-forming sedge all decrease with high levels of grazing. Most species exhibit an ephemeral life strategy in response to unreliable rainfall, and this boom and bust strategy effectively doubles as an adaptation to grazing. After 20 years of exposure to managed grazing with domestic stock in Australian dune swales, patterns in species richness have not emerged in response to grazing pressure, the ecosystem has not been transformed to another degradation "state," and there is no evidence that grazing relief refuges provide havens for species highly sensitive to grazing.

  2. Impacts of livestock grazing and tree clearing on birds of woodland and riparian habitats.

    PubMed

    Martin, Tara G; McIntyre, S

    2007-04-01

    We investigated the impact of pastoral management on birds in subtropical grassy eucalypt woodland in southeastern Queensland, Australia, where the patterns of land management have made it possible to disentangle the effects of livestock grazing from those of tree clearing. We recorded changes in bird species composition, density, and relative abundance across two woodland habitat types (riparian and nonriparian) and two levels of clearing (wooded and nonwooded) and three levels of livestock grazing (low, moderate, and high) replicated over space (1000 km(2)) and time (2001-2002). We predicted that species that depend on understory vegetation would be most negatively affected by livestock grazing. A Bayesian generalized linear model showed that the level of grazing had the greatest effect when trees were present. When trees were absent, the impact of grazing was overshadowed by the effects of a lack of trees. Over 65% of species responded to different levels of grazing, and the abundance of 42% of species varied markedly with habitat and grazing. The most common response to grazing was high species relative abundance under low levels of grazing (28% of species), species absence at high levels of grazing (20%), and an increase in abundance with increasing grazing (18%). Despite having similar bird assemblages, the effect of grazing was stronger in riparian habitat than in adjacent woodland habitat. Our results suggest that any level of commercial livestock grazing is detrimental to some woodland birds, particularly the understory-dependant species, as predicted. Nevertheless, provided trees are not cleared, a rich and abundant bird fauna can coexist with moderate levels of grazing. Habitats with high levels of grazing, on the other hand, resulted in a species-poor bird assemblage dominated by birds that are increasing in abundance nationally.

  3. Measuring grazing-angle DHR with the infrared grazing angle reflectometer

    NASA Astrophysics Data System (ADS)

    Benson, Michael R.; Marciniak, Michael A.; Burks, Jeffrey W.

    2012-10-01

    The Infrared Grazing Angle Reflectometer allows measurement of Directional Hemispherical Reflectance (DHR) at very high angles of incidence (30 to 85 degrees) and at wavelengths ranging from 4.3 to 10.8 microns. A hemi-ellipsoidal mirror redirects the reflected light and reflects it on to a novel five-sided pyroelectric detector. The incident light intensity is measured and used in calculating the DHR of the sample. In this paper, the theory of operation of this detector is derived, and used to simulate the operation of the system. This simulation of the detector shows errors of 3% or less for both diffuse and specular samples, compared to the theoretical DHR. The calibration method defined in this paper allows for high accuracy and ease of use without knowing the specific attributes of the optics used in the system. Finally, collected DHR data is compared with the simulated data for comparison. Comparing the measured data to the simulation shows that the model correctly predicts the locations and trends of the scattered energy.

  4. Soil bacterial community responses to warming and grazing in a Tibetan alpine meadow.

    PubMed

    Li, Yaoming; Lin, Qiaoyan; Wang, Shiping; Li, Xiangzhen; Liu, Wentso; Luo, Caiyun; Zhang, Zhenhua; Zhu, Xiaoxue; Jiang, Lili; Li, Xine

    2016-01-01

    Warming and grazing significantly affect the structure and function of an alpine meadow ecosystem. Yet, the responses of soil microbes to these disturbances are not well understood. Controlled asymmetrical warming (+1.2/1.7°C during daytime/nighttime) with grazing experiments were conducted to study microbial response to warming, grazing and their interactions. Significant interactive effects of warming and grazing were observed on soil bacterial α-diversity and composition. Warming only caused significant increase in bacterial α-diversity under no-grazing conditions. Grazing induced no substantial differences in bacterial α-diversity and composition irrespective of warming. Warming, regardless of grazing, caused a significant increase in soil bacterial community similarity across space, but grazing only induced significant increases under no-warming conditions. The positive effects of warming on bacterial α-diversity and grazing on community similarity were weakened by grazing and warming, respectively. Soil and plant variables explained well the variations in microbial communities, indicating that changes in soil and plant properties may primarily regulate soil microbial responses to warming in this alpine meadow. The results suggest that bacterial communities may become more similar across space in a future, warmed climate and moderate grazing may potentially offset, at least partially, the effects of global warming on the soil microbial diversity.

  5. Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales.

    PubMed

    Monroe, Adrian P; Aldridge, Cameron L; Assal, Timothy J; Veblen, Kari E; Pyke, David A; Casazza, Michael L

    2017-03-22

    Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) and timing across a gradient in vegetation productivity as measured by the Normalized Vegetation Difference Index (NDVI). We found grazing can have both positive and negative effects on Sage-grouse populations depending on the timing and level of grazing. Sage-grouse populations responded positively to higher grazing levels after peak vegetation productivity, but populations declined when similar grazing levels occurred earlier, likely reflecting the sensitivity of cool-season grasses to grazing during peak growth periods. We also found support for the hypothesis that effects of grazing management vary with local vegetation productivity. These results illustrate the importance of broad-scale analyses by revealing patterns in Sage-grouse population trends that may not be inferred from studies at finer scales, and could inform sustainable grazing management in these ecosystems.

  6. Is grazing exclusion effective in restoring vegetation in degraded alpine grasslands in Tibet, China?

    PubMed Central

    Yan, Yan

    2015-01-01

    Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in Tibet to investigate the effect of grazing exclusion on plant community structure and biomass. Our results showed that species biodiversity indicators, including the Pielou evenness index, the Shannon–Wiener diversity index, and the Simpson dominance index, did not significantly change under grazing exclusion conditions. In contrast, the total vegetation cover, the mean vegetation height of the community, and the aboveground biomass were significantly higher in the grazing exclusion grasslands than in the free grazed grasslands. These results indicated that grazing exclusion is an effective measure for maintaining community stability and improving aboveground vegetation growth in alpine grasslands. However, the statistical analysis showed that the growing season precipitation (GSP) plays a more important role than grazing exclusion in which influence on vegetation in alpine grasslands. In addition, because the results of the present study come from short term (6–8 years) grazing exclusion, it is still uncertain whether these improvements will be continuable if grazing exclusion is continuously implemented. Therefore, the assessments of the ecological effects of the grazing exclusion management strategy on degraded alpine grasslands in Tibet still need long term continued research. PMID:26157607

  7. Feedback dynamics of grazing lawns: Coupling vegetation change with animal growth

    USGS Publications Warehouse

    Person, Brian T.; Herzog, M.P.; Ruess, Roger W.; Sedinger, J.S.; Anthony, R. Michael; Babcock, C.A.

    2003-01-01

    We studied the effects of grazing by Black Brant (Branta bernicla nigricans) geese (hereafter Brant) on plant community zonation and gosling growth between 1987 and 2000 at a nesting colony in southwestern Alaska. The preferred forage of Brant, Carex subspathacea, is only found as a grazing lawn. An alternate forage species, C. ramenskii, exists primarily as meadow but also forms grazing lawns when heavily grazed. We mowed plots of ungrazed C. ramenskii meadows to create swards that Brant could select and maintain as grazing lawns. Fecal counts were higher on mowed plots than on control plots in the year after plots were mowed. Both nutritional quality and aboveground biomass of C. ramenskii in mowed plots were similar to that of C. subspathacea grazing lawns. The areal extent of grazing lawns depends in part on the population size of Brant. High Brant populations can increase the areal extent of grazing lawns, which favors the growth of goslings. Grazing lawns increased from 3% to 8% of surface area as the areal extent of C. ramenskii meadows declined between 1991 and 1999. Gosling mass was lower early in this time period due to density dependent effects. As the goose population stabilized, and area of grazing lawns increased, gosling mass increased between 1993 and 1999. Because larger goslings have increased survival, higher probability of breeding, and higher fecundity, herbivore-mediated changes in the distribution grazing lawn extent may result in a numerical increase of the population within the next two decades.

  8. Is grazing exclusion effective in restoring vegetation in degraded alpine grasslands in Tibet, China?

    PubMed

    Yan, Yan; Lu, Xuyang

    2015-01-01

    Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in Tibet to investigate the effect of grazing exclusion on plant community structure and biomass. Our results showed that species biodiversity indicators, including the Pielou evenness index, the Shannon-Wiener diversity index, and the Simpson dominance index, did not significantly change under grazing exclusion conditions. In contrast, the total vegetation cover, the mean vegetation height of the community, and the aboveground biomass were significantly higher in the grazing exclusion grasslands than in the free grazed grasslands. These results indicated that grazing exclusion is an effective measure for maintaining community stability and improving aboveground vegetation growth in alpine grasslands. However, the statistical analysis showed that the growing season precipitation (GSP) plays a more important role than grazing exclusion in which influence on vegetation in alpine grasslands. In addition, because the results of the present study come from short term (6-8 years) grazing exclusion, it is still uncertain whether these improvements will be continuable if grazing exclusion is continuously implemented. Therefore, the assessments of the ecological effects of the grazing exclusion management strategy on degraded alpine grasslands in Tibet still need long term continued research.

  9. Plant compensation to grazing and soil carbon dynamics in a tropical grassland

    PubMed Central

    2014-01-01

    The effects of grazing on soil organic carbon (SOC) dynamics, particularly in the tropics, are still poorly understood. Plant compensation to grazing, whereby plants maintain leaf area (C input capacity) despite consumption (C removal) by grazers, has been demonstrated in tropical grasslands but its influence on SOC is largely unexplored. Here, the effect of grazing on plant leaf area index (LAI) was measured in a field experiment in Serengeti National Park, Tanzania. LAI changed little for grazing intensities up to 70%. The response curve of LAI versus grazing intensity was used in a mass balance model, called SNAP, of SOC dynamics based on previous data from the Serengeti. The model predicted SOC to increase at intermediate grazing intensity, but then to decline rapidly at the highest grazing intensities. The SNAP model predictions were compared with observed SOC stocks in the 24 grazed plots of a 10-year grazing exclosure experiment at eight sites across the park that varied in mean annual rainfall, soil texture, grazing intensity and plant lignin and cellulose. The model predicted current SOC stocks very well (R2 > 0.75), and suggests that compensatory plant responses to grazing are an important means of how herbivores might maintain or increase SOC in tropical grasslands. PMID:24498573

  10. Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales

    USGS Publications Warehouse

    Monroe, Adrian; Aldridge, Cameron; Assal, Timothy J.; Veblen, Kari E.; Pyke, David A.; Casazza, Michael L.

    2017-01-01

    Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004–2014, we modeled population trends in response to grazing level (represented by a relative grazing index) and timing across a gradient in vegetation productivity as measured by the Normalized Vegetation Difference Index (NDVI). We found grazing can have both positive and negative effects on Sage-grouse populations depending on the timing and level of grazing. Sage-grouse populations responded positively to higher grazing levels after peak vegetation productivity, but populations declined when similar grazing levels occurred earlier, likely reflecting the sensitivity of cool-season grasses to grazing during peak growth periods. We also found support for the hypothesis that effects of grazing management vary with local vegetation productivity. These results illustrate the importance of broad-scale analyses by revealing patterns in Sage-grouse population trends that may not be inferred from studies at finer scales, and could inform sustainable grazing management in these ecosystems.

  11. The influence of grazing on surface climatological variables of tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Seastedt, T. R.; Dyer, M. I.; Turner, Clarence L.

    1992-01-01

    Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables.

  12. Positive short-term effects of sheep grazing on the alpine avifauna.

    PubMed

    Loe, Leif Egil; Mysterud, Atle; Stien, Audun; Steen, Harald; Evans, Darren M; Austrheim, Gunnar

    2007-02-22

    Grazing by large herbivores may negatively affect bird populations. This is of great conservation concern in areas with intensive sheep grazing. Sheep management varies substantially between regions, but no study has been performed in less intensively grazed systems. In a fully replicated, landscape scale experiment with three levels of sheep grazing, we tested whether the abundance and diversity of an assemblage of mountain birds were negatively affected by grazing or if grazing facilitated the bird assemblage. Density of birds was higher at high sheep density compared with low sheep density or no sheep by the fourth grazing season, while there was no clear effect on bird diversity. Thus, agricultural traditions and land use politics determining sheep density may change the density of avifauna in either positive or negative directions.

  13. Evaluating Attitudes towards Changes in Rural Landscape by Grazing Cattle on Abandoned Paddy Fields

    NASA Astrophysics Data System (ADS)

    Yasuhito, Kitai; Toshihiro, Hattori; Hiroshi, Takahashi

    The appearance of cattle grazing abandoned paddy fields can be used to evaluate attitudes towards this land-use change. The semantic differential (SD) method was used families of a university student to evaluate and compare attitudes towards five types of rural landscape: pasture, pasture grazed by cattle, rice paddy field, abandoned paddy field converted to pasture and abandoned paddy field converted to pasture grazed by cattle. Cattle grazing abandoned paddy fields were determined to have a positive effect on the landscape. However, all grazing cattle created a negative attitude because of the unclean appearance of the landscape. Grazing cattle at high stocking rates in small areas could create a negative attitude because of the oppressive appearance of the landscape. The acceptance of grazing cattle was lower if the animals ware newly introduced to the landscape.

  14. 77 FR 70137 - Okanogan-Wenatchee National Forest, Okanogan County, WA; Bannon, Aeneas, Revis, and Tunk Grazing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... continue authorizing cattle grazing on all or portions of four existing grazing allotments: Bannon, Aeneas... to authorize grazing at current permitted cattle numbers and seasons of use. DATES: Comments... be reached and cattle need to be moved. The length of time each pasture is grazed and whether...

  15. 25 CFR 166.406 - Whose grazing rental rate will be applicable for a permit on government land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Whose grazing rental rate will be applicable for a permit... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.406 Whose grazing rental rate will be applicable for a...

  16. 25 CFR 166.422 - What does the BIA do with grazing rental payments received from permittees?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What does the BIA do with grazing rental payments... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.422 What does the BIA do with grazing rental payments received...

  17. 43 CFR 4.470 - How to appeal a final BLM grazing decision to an administrative law judge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How to appeal a final BLM grazing decision... Hearings and Appeals Grazing Procedures (inside and Outside Grazing Districts) § 4.470 How to appeal a final BLM grazing decision to an administrative law judge. (a) Any applicant, permittee, lessee,...

  18. 25 CFR 166.416 - May a permittee make a grazing rental payment in advance of the due date?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false May a permittee make a grazing rental payment in advance... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.416 May a permittee make a grazing rental payment in advance of the due date? Rent may...

  19. 25 CFR 166.422 - What does the BIA do with grazing rental payments received from permittees?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What does the BIA do with grazing rental payments... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.422 What does the BIA do with grazing rental payments received...

  20. 43 CFR 4.471 - How to petition for a stay of a final BLM grazing decision.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing decision. 4.471 Section 4.471 Public Lands: Interior Office of the Secretary of the Interior... Grazing Procedures (inside and Outside Grazing Districts) § 4.471 How to petition for a stay of a final BLM grazing decision. (a) An appellant under § 4.470 may petition for a stay of the final BLM...

  1. 25 CFR 166.411 - Will a permittee be notified when a grazing rental payment is due?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Will a permittee be notified when a grazing rental... AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.411 Will a permittee be notified when a grazing rental payment is due? Each permit states...

  2. 25 CFR 166.406 - Whose grazing rental rate will be applicable for a permit on government land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Whose grazing rental rate will be applicable for a permit... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.406 Whose grazing rental rate will be applicable for a...

  3. 25 CFR 166.411 - Will a permittee be notified when a grazing rental payment is due?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Will a permittee be notified when a grazing rental... AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.411 Will a permittee be notified when a grazing rental payment is due? Each permit states...

  4. 25 CFR 166.423 - How do Indian landowners receive grazing rental payments that the BIA has received from permittees?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How do Indian landowners receive grazing rental payments..., DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.423 How do Indian landowners receive grazing...

  5. 43 CFR 4.470 - How to appeal a final BLM grazing decision to an administrative law judge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How to appeal a final BLM grazing decision... Hearings and Appeals Grazing Procedures (inside and Outside Grazing Districts) § 4.470 How to appeal a final BLM grazing decision to an administrative law judge. (a) Any applicant, permittee, lessee,...

  6. 25 CFR 166.404 - Whose grazing rental rate will be applicable for a permit on tribal land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Whose grazing rental rate will be applicable for a permit... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.404 Whose grazing rental rate will be applicable for a permit on tribal...

  7. 25 CFR 166.423 - How do Indian landowners receive grazing rental payments that the BIA has received from permittees?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How do Indian landowners receive grazing rental payments..., DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.423 How do Indian landowners receive grazing...

  8. 43 CFR 4.471 - How to petition for a stay of a final BLM grazing decision.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... grazing decision. 4.471 Section 4.471 Public Lands: Interior Office of the Secretary of the Interior... Grazing Procedures (inside and Outside Grazing Districts) § 4.471 How to petition for a stay of a final BLM grazing decision. (a) An appellant under § 4.470 may petition for a stay of the final BLM...

  9. 25 CFR 166.416 - May a permittee make a grazing rental payment in advance of the due date?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false May a permittee make a grazing rental payment in advance... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.416 May a permittee make a grazing rental payment in advance of the due date? Rent may...

  10. 25 CFR 166.404 - Whose grazing rental rate will be applicable for a permit on tribal land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Whose grazing rental rate will be applicable for a permit... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.404 Whose grazing rental rate will be applicable for a permit on tribal...

  11. 43 CFR 4130.4 - Authorization of temporary changes in grazing use within the terms and conditions of permits and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing use within the terms and conditions of permits and leases, including temporary nonuse. 4130.4... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.4 Authorization of temporary changes in grazing use within the terms...

  12. Testing the limits of resistance: a 19-year study of Mediterranean grassland response to grazing regimes.

    PubMed

    Sternberg, Marcelo; Golodets, Carly; Gutman, Mario; Perevolotsky, Avi; Ungar, Eugene D; Kigel, Jaime; Henkin, Zalmen

    2015-05-01

    A synthesis of a long-term (19 years) study assessing the effects of cattle grazing on the structure and composition of a Mediterranean grassland in north-eastern Israel is presented, with new insights into the response of the vegetation to grazing management and rainfall. We hypothesized that the plant community studied would be resistant to high grazing intensities and rainfall variability considering the combined long history of land-use and unpredictable climatic conditions where this community evolved. Treatments included manipulations of stocking densities (moderate, heavy, and very heavy) and of grazing regimes (continuous vs. seasonal), in a factorial design. The effect of interannual rainfall variation on the expression of grazing impacts on the plant community was minor. The main effects of grazing on relative cover of plant functional groups were related to early vs. late seasonal grazing. Species diversity and equitability were remarkably stable across all grazing treatments. A reduction in tall grass cover at higher stocking densities was correlated with increased cover of less palatable groups such as annual and perennial thistles, as well as shorter and prostrate groups such as short annual grasses. This long-term study shows that interannual fluctuations in plant functional group composition could be partly accounted for by grazing pressure and timing, but not by the measured rainfall variables. Grazing affected the dominance of tall annual grasses. However, the persistence of tall grasses and more palatable species over time, despite large differences in grazing pressure and timing, supports the idea that Mediterranean grasslands are highly resistant to prolonged grazing. Indeed, even under the most extreme grazing conditions applied, there were no signs of deterioration or collapse of the ecosystem. This high resistance to grazing intensity and interannual fluctuation in climatic conditions should favor the persistence of the plant community under

  13. Differential expression of the skeletal muscle proteome in grazed cattle.

    PubMed

    Shibata, M; Matsumoto, K; Oe, M; Ohnishi-Kameyama, M; Ojima, K; Nakajima, I; Muroya, S; Chikuni, K

    2009-08-01

    The objective of this study was to investigate the differences in the muscle proteome of grass-fed and grain-fed cattle. Eight Japanese Black Cattle 10 mo of age were separated randomly into 2 groups: 1) grazing (grass-fed) and 2) concentrate (grain-fed) groups. All cattle were first housed individually in a stall barn and fed a combination of concentrate ad libitum and Italian ryegrass hay until 21 mo of age. After this control period, the 4 grass-fed cattle were placed on outdoor pasture, whereas the other 4 grain-fed cattle continued on the concentrate diet. The cattle were slaughtered at 27 mo of age, and tissues from the semitendinosus muscle were obtained for use in proteome analysis. Differential expression of muscle proteins in the 2 groups was carried out using 2-dimensional gel electrophoresis (2DE) and Western blot analyses, with subsequent mass spectrometry. Approximately 200 individual protein spots were detected and compared in each group using 2DE, of which 20 and 9 spots, respectively, showed differences in the spot intensity for the sarcoplasmic fraction and myofibrillar fraction. In the grazing group, the relative intensity of spots was significantly greater for adenylate kinase 1 and myoglobin in the sarcoplasmic fraction, and for slow-twitch myosin light chain 2 in the myofibrillar fraction (P < 0.05), than the concentrate group. The relative spot intensity of several glycolytic enzymes was significantly greater in the grazing group, such as beta-enolase 3, fructose-1,6-bisphosphate aldolase A, triosephosphate isomerase, and heat shock 27 kDa protein (P < 0.05). Moreover, significantly greater slow twitch of troponin T, troponin I, and myosin heavy chain of semitendinosus muscle was detected in the grazing group than in the concentrate group using Western blot analysis (P < 0.05). Several previous reports have described that the slow-twitch muscle contents affect elements of nutrition, flavor, and food texture of meat. This study revealed muscle

  14. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    NASA Astrophysics Data System (ADS)

    Badgery, Warwick; Zhang, Yingjun; Huang, Ding; Broadfoot, Kim; Kemp, David; Mitchell, David

    2015-04-01

    Stocking rate and grazing management can be altered to enhance the sustainable production of grasslands but the relative influence of each has not often been determined for native temperate grasslands. Grazing management can range from seasonal rests through to intensive rotational grazing involving >30 paddocks. In large scale grazing, it can be difficult to segregate the influence of grazing pressure from the timing of utilisation. Moreover, relative grazing pressure can change between years as seasonal conditions influence grassland production compared to the relative constant requirements of animals. This paper reports on two studies in temperate native grasslands of northern China and south eastern Australia that examined stocking rate and regionally relevant grazing management strategies. In China, the grazing experiment involved combinations of a rest, moderate or heavy grazing pressure of sheep in spring, then moderate or heavy grazing in summer and autumn. Moderate grazing pressure at 50% of the current district average, resulted in the better balance between maintaining productive and diverse grasslands, a profitable livestock system, and mitigation of greenhouse gases through increased soil carbon, methane uptake by the soil, and efficient methane emissions per unit of weight gain. Spring rests best maintained a desirable grassland composition, but had few other benefits and reduced livestock productivity due to lower feed quality from grazing later in the season. In Australia, the grazing experiment compared continuous grazing to flexible 4- and 20-paddock rotational grazing systems with sheep. Stocking rates were adjusted between systems biannually based on the average herbage mass of the grassland. No treatment degraded the perennial pasture composition, but ground cover was maintained at higher levels in the 20-paddock system even though this treatment had a higher stocking rate. Overall there was little difference in livestock production (e.g. kg

  15. [Effect of grazing on grassland under protective plantation in the ecotone between agriculture and animal husbandry or Songnen plain].

    PubMed

    He, Nianpeng; Wu, Ling; Zhou, Daowei

    2004-05-01

    Based on the current special position that grassland under protective plantation is one of the most important grazing spaces of the ecotone between agriculture and animal husbandry in Songnen plain, an experiment was conducted to investigate the effect of grazing on grassland under protective plantation. The results showed that no-grazing grassland in the grassland under protective plantation was seriously degenerated, but light and moderate grazing could stimulate the growth of grass and the product and quality of grassland. The index of grassland quality (IGQ) of no-grazing grassland was the lowest (15.51), attributing to serious degradation, while that of light grazing grassland was the highest (86.41), and the IGQ was decreased with increasing grazing intensity. Therefore, in order to stimulate the grass growth of the grassland, fully utilize the leaves of poplar, and increase the available forage resources, light and moderate grazing intensity should be advocated, but no-grazing and extreme grazing should be avoided.

  16. Active full-shell grazing-incidence optics

    NASA Astrophysics Data System (ADS)

    Roche, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffrey J.; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2016-09-01

    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  17. Chronic parrotfish grazing impedes coral recovery after bleaching

    NASA Astrophysics Data System (ADS)

    Rotjan, Randi D.; Dimond, James L.; Thornhill, Daniel J.; Leichter, James J.; Helmuth, Brian; Kemp, Dustin W.; Lewis, Sara M.

    2006-08-01

    Coral bleaching, in which corals become visibly pale and typically lose their endosymbiotic zooxanthellae ( Symbiodinium spp.), increasingly threatens coral reefs worldwide. While the proximal environmental triggers of bleaching are reasonably well understood, considerably less is known concerning physiological and ecological factors that might exacerbate coral bleaching or delay recovery. We report a bleaching event in Belize during September 2004 in which Montastraea spp. corals that had been previously grazed by corallivorous parrotfishes showed a persistent reduction in symbiont density compared to intact colonies. Additionally, grazed corals exhibited greater diversity in the genetic composition of their symbiont communities, changing from uniform ITS2 type C7 Symbiodinium prior to bleaching to mixed assemblages of Symbiodinium types post-bleaching. These results suggest that chronic predation may exacerbate the influence of environmental stressors and, by altering the coral-zooxanthellae symbiosis, such abiotic-biotic interactions may contribute to spatial variation in bleaching processes.

  18. Grazing-activated chemical defence in a unicellular marine alga

    NASA Astrophysics Data System (ADS)

    Wolfe, Gordon V.; Steinke, Michael; Kirst, Gunter O.

    1997-06-01

    Marine plankton use a variety of defences against predators, some of which affect trophic structure and biogeochemistry. We have previously shown that, during grazing by the protozoan Oxyrrhis marina on the alga Emiliania huxleyi, dimethylsulphoniopropionate (DMSP) from the prey is converted to dimethyl sulphide (DMS) when lysis of ingested prey cells initiates mixing of algal DMSP and the enzyme DMSP lyase. Such a mechanism is similar to macrophyte defence reactions,. Here we show that this reaction deters protozoan herbivores, presumably through the production of highly concentrated acrylate, which has antimicrobial activity. Protozoan predators differ in their ability to ingest and survive on prey with high-activity DMSP lyase, but all grazers preferentially select strains with low enzyme activity when offered prey mixtures. This defence system involves investment in a chemical precursor, DMSP, which is not self-toxic and has other useful metabolic functions. We believe this is the first report of grazing-activated chemical defence in unicellular microorganisms.

  19. Free-grazing ducks and highly pathogenic avian influenza, Thailand.

    PubMed

    Gilbert, Marius; Chaitaweesub, Prasit; Parakamawongsa, Tippawon; Premashthira, Sith; Tiensin, Thanawat; Kalpravidh, Wantanee; Wagner, Hans; Slingenbergh, Jan

    2006-02-01

    Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004-May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread. This finding could be important for other duck-producing regions in eastern and southeastern Asian countries affected by HPAI.

  20. Protozoan grazing reduces the current output of microbial fuel cells.

    PubMed

    Holmes, Dawn E; Nevin, Kelly P; Snoeyenbos-West, Oona L; Woodard, Trevor L; Strickland, Justin N; Lovley, Derek R

    2015-10-01

    Several experiments were conducted to determine whether protozoan grazing can reduce current output from sediment microbial fuel cells. When marine sediments were amended with eukaryotic inhibitors, the power output from the fuel cells increased 2-5-fold. Quantitative PCR showed that Geobacteraceae sequences were 120 times more abundant on anodes from treated fuel cells compared to untreated fuel cells, and that Spirotrichea sequences in untreated fuel cells were 200 times more abundant on anode surfaces than in the surrounding sediments. Defined studies with current-producing biofilms of Geobacter sulfurreducens and pure cultures of protozoa demonstrated that protozoa that were effective in consuming G. sulfurreducens reduced current production up to 91% when added to G. sulfurreducens fuel cells. These results suggest that anode biofilms are an attractive food source for protozoa and that protozoan grazing can be an important factor limiting the current output of sediment microbial fuel cells. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Active Full-Shell Grazing-Incidence Optics

    NASA Technical Reports Server (NTRS)

    Davis, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2016-01-01

    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  2. Adjustable Grazing-Incidence X-Ray Optics

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Reid, Paul B.

    2015-01-01

    With its unique subarcsecond imaging performance, NASA's Chandra X-ray Observatory illustrates the importance of fine angular resolution for x-ray astronomy. Indeed, the future of x-ray astronomy relies upon x-ray telescopes with comparable angular resolution but larger aperture areas. Combined with the special requirements of nested grazing-incidence optics, mass, and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. The goal of this technology research is to enable the cost-effective fabrication of large-area, lightweight grazing-incidence x-ray optics with subarcsecond resolution. Toward this end, the project is developing active x-ray optics using slumped-glass mirrors with thin-film piezoelectric arrays for correction of intrinsic or mount-induced distortions.

  3. Free-grazing Ducks and Highly Pathogenic Avian Influenza, Thailand

    PubMed Central

    Chaitaweesub, Prasit; Parakamawongsa, Tippawon; Premashthira, Sith; Tiensin, Thanawat; Kalpravidh, Wantanee; Wagner, Hans; Slingenbergh, Jan

    2006-01-01

    Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004–May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread. This finding could be important for other duck-producing regions in eastern and southeastern Asian countries affected by HPAI. PMID:16494747

  4. Method of Measuring Dinoflagellate Grazing on Flagellate and Bacteria Communities

    NASA Astrophysics Data System (ADS)

    Price, L. M.; Mulholland, M. R.

    2016-02-01

    Dinoflagellates are a major taxa of phytoplankton that include many species that commonly form harmful algal blooms (HABs) throughout the world. A feature of dinoflagellate physiology that may contribute to their competitive success is their ability to grow mixotrophically. As primary producers and photoautotrophs, these organisms convert inorganic nutrients to organic compounds using sunlight. During blooms inorganic nutrients and light commonly become limited. The ability to grow heterotrophically may offer dinoflagellates a competitive advantage over strict autotrophs during blooms. Using a modification of a method used to measure zooplankton grazing rates, we measured grazing by dinoflagellates on co-occurring microbes, including heterotrophic flagellates and bacteria, in the Lafayette River, a tributary in the Chesapeake Bay estuary during non-bloom and bloom conditions. Initial results of these experiments using this method are presented here.

  5. Grazing-incidence antireflection films. I. Basic theory

    NASA Astrophysics Data System (ADS)

    Hannon, J. P.; Hung, N. V.; Trammell, G. T.; Gerdau, E.; Mueller, M.; Rüffer, R.; Winkler, H.

    1985-10-01

    We discuss the possibility of a new interference technique for x-ray and γ-ray optics-the simple idea of grazing-incidence antireflection films (GIAR films)-for creating high-efficiency antireflection coatings for near-grazing-incidence reflection of hard x rays and γ rays. The motivation is the possible application to producing ``ultranarrow'' bandpass filters for synchrotron radiation with frequency widths ~=10-8-10-6 eV, giving a unique high-resolution, long-coherence-length, x-ray source for probing soft inelastic excitations and opening up new possibilities in x-ray interferometry. In this first of two papers on nonresonant GIAR films, we develop the basic theory and discuss in detail the simplest ideas for achieving antireflection films-impedance-matched quarter-wave films and damping stabilized solutions-which can both be obtained by coating a high-density mirror with a single lower-density film.

  6. Properties and performance of grazing-incidence mirror systems

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    1982-04-01

    We investigate the performance of, and the origin of aberrations in, beam lines based on simple and the recently proposed CARSA mirror elements. New results include the identification of the sums of off-grazing angles and their squares as figures of merit for total reflectance and scattering losses in near-grazing-incidence systems, and the discovery that the usual image distortions and aberrations previously associated with simple elements can essentially be eliminated with pairs of elliptical mirrors having a common rotational symmetry axis. Slit throughput efficiencies and sensitivities to system stability are calculated for both horizontal and vertical dispersion for several representative beam lines using a ray-tracing program developed for CARSA systems. We find that high-resolution operation is possible with no entrance slit for CARSA combinations.

  7. Conservative deterministic spectral Boltzmann solver near the grazing collisions limit

    NASA Astrophysics Data System (ADS)

    Haack, Jeffrey R.; Gamba, Irene M.

    2012-11-01

    We present new results building on the conservative deterministic spectral method for the space homogeneous Boltzmann equation developed by Gamba and Tharkabhushaman. This approach is a two-step process that acts on the weak form of the Boltzmann equation, and uses the machinery of the Fourier transform to reformulate the collisional integral into a weighted convolution in Fourier space. A constrained optimization problem is solved to preserve the mass, momentum, and energy of the resulting distribution. Within this framework we have extended the formulation to the case of more general case of collision operators with anisotropic scattering mechanisms, which requires a new formulation of the convolution weights. We also derive the grazing collisions limit for the method, and show that it is consistent with the Fokker-Planck-Landau equations as the grazing collisions parameter goes to zero.

  8. Simulating the onset of grazing envelope evolution of binary stars

    NASA Astrophysics Data System (ADS)

    Shiber, Sagiv; Kashi, Amit; Soker, Noam

    2017-02-01

    We present the first three-dimensional gas-dynamical simulations of the grazing envelope evolution (GEE) of stars, with the goal of exploring the basic flow properties and the role of jets at the onset of the GEE. In the simulated runs, a secondary main-sequence star grazes the envelope of the primary asymptotic giant branch (AGB) star. The orbit is circular at the radius of the AGB primary star on its equator. We inject two opposite jets perpendicular to the equatorial plane from the location of the secondary star, and follow the evolution for several orbital periods. We explore the flow pattern by which the jets eject the outskirts of the AGB envelope. After one orbit, the jets start to interact with gas ejected in previous orbits and inflate hot low-density bubbles.

  9. Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Turner, Jefferson T.; Borkman, David G.

    2005-09-01

    Zooplankton grazing was investigated by shipboard experiments during natural blooms of Alexandrium spp. in the offshore Gulf of Maine in spring and/or summer of 1998, 2000, and 2001. Grazing studies were done in conjunction with studies of accumulation of Alexandrium toxins in the zooplankton, as part of the ECOHAB-Gulf of Maine regional program. Several species of copepods, marine cladocerans, and appendicularians were allowed to graze upon natural phytoplankton assemblages, at ambient temperatures (14-17 °C). Grazing was measured by quantitative microscopic analyses of disappearance of phytoplankton cells in initial, control, and experimental food suspensions. Thus, we were able to examine grazing upon Alexandrium in comparison to grazing on other co-occurring phytoplankton taxa. Even during Alexandrium "blooms," this dinoflagellate was a minor component of the overall phytoplankton assemblage. It was present at stations where grazing experiments were conducted at levels of 0.12-7.57×10 3 cells l -1, or 0.03-3.93% of total phytoplankton cells. Maximum ingestion of Alexandrium accounted for only up to 3.2% of total cells ingested. Phytoplankton assemblages were dominated by athecate microflagellates, and to a lesser extent by diatoms and non-toxic dinoflagellates. Microflagellates were present at abundances of 159.62-793.93 cells ml -1, or 60.6-95.56% of total cells. Grazing on microflagellates accounted for 35.59-98.21% of total grazing. Grazing on Alexandrium spp. and microflagellates was generally non-selective, with these taxa being ingested in similar proportions to their availability in food assemblages. Grazing on diatoms was selective, with diatoms being disproportionately ingested, compared to their proportions in food assemblages. There were no apparent adverse effects of Alexandrium on grazers during incubations of 18-24 h, and grazer survival was 100%. Estimated daily zooplankton grazing impact on Alexandrium spp. field populations by field

  10. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    PubMed

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  11. Grazing and Metabolism of Euphausia pacifica in the Yellow Sea

    PubMed Central

    Tao, Zhencheng; Li, Chaolun; Sun, Song

    2015-01-01

    Grazing and metabolism of Euphausia pacifica in the Yellow Sea were studied from September 2006 to August 2007. Euphausia pacifica is a selective-feeding omnivore and grazing rates among different months were monitored using a Coulter Counter and batch culture feeding experiments. Euphausia pacifica mainly grazed microzooplankton in August and September, which resulted in an increase in chlorophyll a concentration. Oxygen consumption rate of E. pacifica was 38.7–42.5 μmol O2 g-1 DW h-1 in March, which was four times higher than the oxygen consumption rates in September and December. The vigorous metabolism of E. pacifica in March consumed 3.1% of body carbon daily, which is likely related to its high reproduction and grazing rate. Respiration and metabolism of E. pacifica in September and December were similar and were lower. O:N ratio of E. pacifica was the highest (17.3–23.8) in March when spawning activity occurred and when food was abundant. The energetic source of E. pacifica during September and December was mostly protein from eating a carnivorous diet, including such items as microzooplankton. Euphausia pacifica was found in cold water at the bottom of the Yellow Sea in summer and autumn and maintained a low consumption status. O:N ratios of E. pacifica in March, September, and December were negatively correlated with SSTs and no significant correlation was found between O:N ratios and chlorophyll a concentration. Seawater temperature is clearly the most important parameter influencing the metabolism of E. pacifica. PMID:25688560

  12. Polarization Techniques for Mitigation of Low Grazing Angle Sea Clutter

    DTIC Science & Technology

    2017-01-01

    explores whether fully polarimetric radar offers a means of enhanc - ing detection performance in low grazing angle sea clutter. To this end, MIT...and whether it can be leveraged in a practical manner to enhance a maritime surveillance radar’s ability to discriminate 1 between object and...the current body of knowledge by exploring the efficacy of leveraging fully polarimetric radar to robustly enhance detection capability using prac

  13. Meteoroids captured into Earth orbit by grazing atmospheric encounters

    NASA Astrophysics Data System (ADS)

    Hills, Jack G.; Goda, M. Patrick

    1997-05-01

    Some meteoroids, such as the one that produced the daytime fireball of August 10, 1972 that passed over the western United States and the European fireball of October 13, 1990, graze the atmosphere of Earth before returning to space (at reduced speed). Other grazing meteoroids, such as Peekskill, penetrate deeper into the atmosphere and lose enough energy to plunge to ground. It is evident that if a grazing meteoroid is within some critical range of closest approach distance and speed, it is captured into a gravitationally bound orbit around Earth. It must ultimately plunge to ground after further orbital dissipation in subsequent atmospheric passages unless the gravitational pull of the Moon and Sun or other intervention raise its perigee above the atmosphere. A spherical atmospheric model is used to integrate the passage of meteoroids in grazing atmospheric encounters. It is found that the corridor for capture narrows with increasing values of V∞, the approach velocity of the meteoroid prior to gravitational acceleration by Earth. As an example, if V∞= 5 km s -1, stony meteoroids with closest-approach distances of h = 40 km above the Earth are captured if their radii, R, are between 3 and 9 m while if V∞ = 15 km s -1 and h = 40 km, they are only captured if R is between 1.5 and 2m. Irons with V∞ = 5 km s -1 and h = 40 km, are captured if R is between 1 and 3.5 m, while if V∞ = 15 km s -1, they are captured if R is between 0.6 and 0.9 m. The cross section for orbital capture of iron meteoroids and small stony meteoroids is about 0.001 that for directly hitting Earth. Large stones are never captured except at very low impact velocities because of the large increase in drag resulting from fragmentation.

  14. High Grazing Angle Sea-Clutter Literature Review

    DTIC Science & Technology

    2013-03-01

    Research, 1986. 91(C11): p. 13065-13083. [45] Stacy, N.J.S., D. Crisp, A. Goh, D. Badger , and M. Preiss. Polarimetric Analysis of Fine Resolution X... Badger , A.S. Goh, M. Preiss, and M.L. Williams. The DSTO Ingara airbone X-Band SAR polarimetric upgrade: first results. IEEE International Geoscience...2012. [65] Rosenberg, L. Persistent Sea-spike Detection in Medium Grazing Angle X-band Sea- clutter. European SAR conference, 2012. [66] Rosenberg, L

  15. Chemical interference among plants mediated by grazing insects.

    PubMed

    Silander, J A; Trenbath, B R; Fox, L R

    1983-06-01

    The experiments on Eucalyptus trees reported here demonstrate that allelopathic effects can be mediated by insects grazing on foliage. We show that the allelochemical nature of insect frass suppresses germination, growth and survival of herb layer species, that plant species vary in their tolerance of this material, and that as a result, the structure and composition of associated, herbaceous understory plant communities are markedly affected by frass fall.

  16. Backscatter from a periodic rough surface at near grazing incidence

    NASA Technical Reports Server (NTRS)

    Dominek, A. K.; Shamansky, H. T.

    1987-01-01

    The effect of periodic surface roughness on the radar cross section (RCS) was studied. The surface roughness was formed by a small sinusoidal variation in a planar surface. RCS measurements were obtained for two different sinusoidal variations near grazing incidence for both principle polarizations. Significant grating lobes were observed in the measurements which directly correspond to the roughness characteristics. A physical optics solution was generated and compared to the measurements with reasonable agreement.

  17. Understanding the spatiotemporal pattern of grazing cattle movement

    PubMed Central

    Zhao, Kun; Jurdak, Raja

    2016-01-01

    Understanding the drivers of animal movement is significant for ecology and biology. Yet researchers have so far been unable to fully understand these drivers, largely due to low data resolution. In this study, we analyse a high-frequency movement dataset for a group of grazing cattle and investigate their spatiotemporal patterns using a simple two-state ‘stop-and-move’ mobility model. We find that the dispersal kernel in the moving state is best described by a mixture exponential distribution, indicating the hierarchical nature of the movement. On the other hand, the waiting time appears to be scale-invariant below a certain cut-off and is best described by a truncated power-law distribution, suggesting that the non-moving state is governed by time-varying dynamics. We explore possible explanations for the observed phenomena, covering factors that can play a role in the generation of mobility patterns, such as the context of grazing environment, the intrinsic decision-making mechanism or the energy status of different activities. In particular, we propose a new hypothesis that the underlying movement pattern can be attributed to the most probable observable energy status under the maximum entropy configuration. These results are not only valuable for modelling cattle movement but also provide new insights for understanding the underlying biological basis of grazing behaviour. PMID:27555220

  18. The ability of winter grazing to reduce wildfire size, intensity ...

    EPA Pesticide Factsheets

    A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behavior metrics, and fire-induced plant mortality in shrub-grasslands. The authors concluded that ungrazed rangelands may experience more fire-induced mortality of native perennial bunchgrasses. The authors also presented several statements regarding the benefits of winter grazing on post-fire plant community responses. However, this commentary will show that the study by Davies et al. has underlying methodological flaws, lacks data necessary to support their conclusions, and does not provide an accurate discussion on the effect of grazing on rangeland ecosystems. Importantly, Davies et al. presented no data on the post-fire mortality of the perennial bunchgrasses or on the changes in plant community composition following their experimental fires. Rather, Davies et al. inferred these conclusions based off their observed fire behavior metrics of maximum temperature and a term described as the “heat load”. However, neither metric is appropriate for elucidating the heat flux impacts on plants. This lack of post-fire data, several methodological flaws, and the use of inadequate metrics describing heat cast doubts on the authors’ ability to support their stated conclusions. This article is a commentary highlights the scientific shortcomings in a forthcoming paper by Davies et al. in the International Journal of Wildland Fire. The study has methodological flaw

  19. Phytoplankton production and grazing balances in the Costa Rica Dome.

    PubMed

    Landry, Michael R; Selph, Karen E; Décima, Moira; Gutiérrez-Rodríguez, Andrés; Stukel, Michael R; Taylor, Andrew G; Pasulka, Alexis L

    2016-03-01

    We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry and pigments and mesozooplankton grazing assessed by gut fluorescence. Three community production estimates, from (14)C uptake (1025 ± 113 mg C m(-2) day(-1)) and from dilution experiments analyzed for total Chla (990 ± 106 mg C m(-2) day(-1)) and flow cytometry populations (862 ± 71 mg C m(-2) day(-1)), exceeded regional ship-based values by 2-3-fold. Picophytoplankton accounted for 56% of community biomass and 39% of production. Production profiles extended deeper for Prochlorococcus (PRO) and picoeukaryotes than for Synechococcus (SYN) and larger eukaryotes, but 93% of total production occurred above 40 m. Microzooplankton consumed all PRO and SYN growth and two-third of total production. Positive net growth of larger eukaryotes in the upper 40 m was balanced by independently measured consumption by mesozooplankton. Among larger eukaryotes, diatoms contributed ∼3% to production. On the basis of this analysis, the CRD region is characterized by high production and grazing turnover, comparable with or higher than estimates for the eastern equatorial Pacific. The region nonetheless displays characteristics atypical of high productivity, such as picophytoplankton dominance and suppressed diatom roles.

  20. Zoonotic echinostome infections in free-grazing ducks in Thailand.

    PubMed

    Saijuntha, Weerachai; Duenngai, Kunyarat; Tantrawatpan, Chairat

    2013-12-01

    Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand.