WorldWideScience

Sample records for grazing lands electronic

  1. Assessment of the Effects of Emerging Grazing Policies on Land ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: This study examines the effects of the emerging grazing policies on land degradation in Nigeria using soil, vegetation ... imposed land use controls divorced from economic and demographic ... may be either positive or negative.

  2. Assessment of the Effects of Emerging Grazing Policies on Land ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... policies on land degradation in Nigeria using soil, vegetation and sustainability as variables for the assessment. ... animals per kilometer square of land and 15,000 persons and 12,500 grazing animals per kilometer square of water. ... OTHER RESOURCES.

  3. Resilience of South African communal grazing lands after the removal of high grazing pressure

    CSIR Research Space (South Africa)

    Harrison, YA

    1999-05-01

    Full Text Available , et al., 1990; Dahlberg, 1993; Scoones, 1993; Shackleton, 1993; Sullivan, 1996). Invariably `overstocking' and hence overgrazing are deemed to be responsible for the apparent degradation. Despite this o cial perspective, most communal lands have... ones (Kelly and Walker, 1976; O'Connor and Pickett, 1992; Parsons, et al., 1997). However, these studies have not indicated the permanence, or reversibility, of the measured changes, and the magnitude of grazing eC128ects is usually minor relative...

  4. Monitoring of livestock grazing effects on Bureau of Land Management land

    Science.gov (United States)

    Veblen, Kari E.; Pyke, David A.; Aldridge, Cameron L.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

    2013-01-01

    Public land management agencies, such as the Bureau of Land Management (BLM), are charged with managing rangelands throughout the western United States for multiple uses, such as livestock grazing and conservation of sensitive species and their habitats. Monitoring of condition and trends of these rangelands, particularly with respect to effects of livestock grazing, provides critical information for effective management of these multiuse landscapes. We therefore investigated the availability of livestock grazing-related quantitative monitoring data and qualitative region-specific Land Health Standards (LHS) data across BLM grazing allotments in the western United States. We then queried university and federal rangeland science experts about how best to prioritize rangeland monitoring activities. We found that the most commonly available monitoring data were permittee-reported livestock numbers and season-of-use data (71% of allotments) followed by repeat photo points (58%), estimates of forage utilization (52%), and, finally, quantitative vegetation measurements (37%). Of the 57% of allotments in which LHS had been evaluated as of 2007, the BLM indicated 15% had failed to meet LHS due to livestock grazing. A full complement of all types of monitoring data, however, existed for only 27% of those 15%. Our data inspections, as well as conversations with rangeland experts, indicated a need for greater emphasis on collection of grazing-related monitoring data, particularly ground cover. Prioritization of where monitoring activities should be focused, along with creation of regional monitoring teams, may help improve monitoring. Overall, increased emphasis on monitoring of BLM rangelands will require commitment at multiple institutional levels.

  5. Cattle grazing and fish recovery on US federal lands: can social-ecological systems science help?

    Science.gov (United States)

    Susan Charnley; Hannah Gosnell; Kendra L Wendel; Mary M Rowland; Michael J Wisdom

    2018-01-01

    In the western US, grazing management on federal lands containing habitat for fish species listed under the US Endangered Species Act (ESA) has sparked social conflict and litigation for decades. To date, the problem has been addressed through a top-down environmental governance system, but rangeland managers and grazing permittees now believe there is a need for more...

  6. Increasing importance of precipitation variability on global livestock grazing lands

    Science.gov (United States)

    Sloat, Lindsey L.; Gerber, James S.; Samberg, Leah H.; Smith, William K.; Herrero, Mario; Ferreira, Laerte G.; Godde, Cécile M.; West, Paul C.

    2018-03-01

    Pastures and rangelands underpin global meat and milk production and are a critical resource for millions of people dependent on livestock for food security1,2. Forage growth, which is highly climate dependent3,4, is potentially vulnerable to climate change, although precisely where and to what extent remains relatively unexplored. In this study, we assess climate-based threats to global pastures, with a specific focus on changes in within- and between-year precipitation variability (precipitation concentration index (PCI) and coefficient of variation of precipitation (CVP), respectively). Relating global satellite measures of vegetation greenness (such as the Normalized Difference Vegetation Index; NDVI) to key climatic factors reveals that CVP is a significant, yet often overlooked, constraint on vegetation productivity across global pastures. Using independent stocking data, we found that areas with high CVP support lower livestock densities than less-variable regions. Globally, pastures experience about a 25% greater year-to-year precipitation variation (CVP = 0.27) than the average global land surface area (0.21). Over the past century, CVP has generally increased across pasture areas, although both positive (49% of pasture area) and negative (31% of pasture area) trends exist. We identify regions in which livestock grazing is important for local food access and economies, and discuss the potential for pasture intensification in the context of long-term regional trends in precipitation variability.

  7. MYCOTOXINS CONTAMINATION IN EDIBLE LAND SNAIL AT GRAZING PADDOCK ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Ime Ebenso

    2013-02-01

    Full Text Available Mycotoxins contamination of animal products is under reported. Juvenile edible land snails (Archachatina marginata were exposed as sentinels in bottomless metal drums for 1 week at abandoned, new and reference sites respectively at grazing paddock environment, to assess the presence of foodborne microbiological mycotoxins contamination during the dry season. Mycological analysis of A. marginata samples revealed high (p<0.05 contamination at all paddocks ranged from 1.2-1.3 x 105 cfu-g. Results revealed values that were found to be unacceptable by FAO/WHO standards. The presence of Aspergillus niger, A. fumigatus and Penicillum expansum were noted as potential toxicogenic mycoflora. Snails were tolerant to all levels of contamination with no clinical signs of infection or mortality. This finding could serve as basis for assessing pre-slaughter microbial contamination of livestock farm/field environment in order to establish data with comparative epidemiological value, which could highlight early warning signals of food safety risk and cross-contamination of mycotoxins in the food chain.

  8. Nickel, Cobalt, Chromium and Copper in agricultural and grazing land soils of Europe

    Science.gov (United States)

    Albanese, Stefano; Sadeghi, Martiya; De Vivo, Benedetto; Lima, Annamaria; Cicchella, Domenico; Dinelli, Enrico

    2014-05-01

    In the framework of the GEMAS (Geochemical Mapping of Agricultural and Grazing Land Soils) project, concentrations of Ni, Co, Cu and Cr were determined for the whole available dataset (2218 samples of agricultural soil and 2127 samples of grazing land soil) covering a total area of 5.6 million sq km all over Europe. The distribution pattern of Ni in the European soils (both agricultural and grazing land soils) shows the highest concentrations in correspondence with the Mediterranean area (especially in Greece, the Balcan Peninsula and NW Italy) with average values generally ranging between 40 mg/kg and 140 mg/kg and anomalous areas characterized by peaks higher than 2400 mg/kg. Concentrations between 10 mg/kg and 40 mg/kg characterize Continental Europe north of Alps and, partly, the Scandinavian countries. Lower concentrations (agricultural and grazing land soils. The maximum concentration peaks of Cobalt and Cr rise up to respectively 126 mg/kg and 696 mg/kg in agricultural soils and up to 255 mg/kg and 577 mg/kg in grazing land soils. Copper distribution in the soils collected across Europe, although has a general correspondence with the patterns of Ni, Co, Cr, shows some peculiarities. Specifically, Cu is characterized by high concentration values (up to 395 mg/kg in agricultural soils and 373 mg/kg in Grazing land soils) also in correspondence with the Roman Comagmatic Province and the south western coast of France characterized by a wide spread of vineyards.

  9. Assessment of the Effects of Emerging Grazing Policies on Land ...

    African Journals Online (AJOL)

    ADOWIE PERE

    carbon sequestration and water filtration. ... temperature of 13oc in the north during the harmattan in ... vegetation cover is removed with the view to obtain ... data concerning environmental degradation mitigation ... in terrestrial ecosystems and driving processes that .... Grazing systems, ecosystem response, and global.

  10. The role of grazing land on the buffalo population dynamics in Brebes regency

    Science.gov (United States)

    Sumanto

    2017-04-01

    Brebes District is one of the centre of grazing buffalo in Indonesia that involve thousands of rearers usually kept as a family savings. This paper highlighted the availability of land and the role of the grazing land for the durability of the maintenance of buffalo in Brebes Regency. The information obtained is from interviewed the livestock facilitators in the sub-district (primary data) and from statistic of agriculture in Brebes Regency 2014 (secondary data). Generally the buffalo kept semi-intensively and commonly the buffaloes graze in the fields that are not used from morning until evening and during nights buffaloes are placed in the stalls. Rearers chose the semi-intensive system in rearing the buffalo because it is considered easy to manage and they do not need to provide fresh money to prepare the roughage for feed, because commonly the grazing buffalo are shepherd by herdman that will receive buffalo as their payment. The population density is very high (1.056 heads/km2), the buffalo ownership is between 2-4 head/households; generally the location of the grazing land is in the forest, rice fields fallow, and sleeping land, and estimated that greenfeed stock is still available abunandtly, on the other hand the urban land is less capacity of feed. The spread of buffalo is only in 125 villages from 297 villages in Brebes. The acceptance of buffalo business is around IDR 3.5 million to IDR 7.5 million/family/year. The availability of grazing land strongly influence the maintaining of buffalo farming by rearers.

  11. Water Quality Conditions Associated with Cattle Grazing and Recreation on National Forest Lands.

    Directory of Open Access Journals (Sweden)

    Leslie M Roche

    Full Text Available There is substantial concern that microbial and nutrient pollution by cattle on public lands degrades water quality, threatening human and ecological health. Given the importance of clean water on multiple-use landscapes, additional research is required to document and examine potential water quality issues across common resource use activities. During the 2011 grazing-recreation season, we conducted a cross sectional survey of water quality conditions associated with cattle grazing and/or recreation on 12 public lands grazing allotments in California. Our specific study objectives were to 1 quantify fecal indicator bacteria (FIB; fecal coliform and E. coli, total nitrogen, nitrate, ammonium, total phosphorus, and soluble-reactive phosphorus concentrations in surface waters; 2 compare results to a water quality regulatory benchmarks, b recommended maximum nutrient concentrations, and c estimates of nutrient background concentrations; and 3 examine relationships between water quality, environmental conditions, cattle grazing, and recreation. Nutrient concentrations observed throughout the grazing-recreation season were at least one order of magnitude below levels of ecological concern, and were similar to U.S. Environmental Protection Agency (USEPA estimates for background water quality conditions in the region. The relative percentage of FIB regulatory benchmark exceedances widely varied under individual regional and national water quality standards. Relative to USEPA's national E. coli FIB benchmarks-the most contemporary and relevant standards for this study-over 90% of the 743 samples collected were below recommended criteria values. FIB concentrations were significantly greater when stream flow was low or stagnant, water was turbid, and when cattle were actively observed at sampling. Recreation sites had the lowest mean FIB, total nitrogen, and soluble-reactive phosphorus concentrations, and there were no significant differences in FIB and

  12. Using the Q10 model to simulate E. coli survival in cowpats on grazing lands

    Science.gov (United States)

    Microbiological quality of surface waters can be affected by microbial load in runoff from grazing lands. This effect, with other factors, depends on the survival of microorganisms in animal waste deposited on pastures. Since temperature is a leading environmental parameter affec...

  13. Historic land use and grazing patterns in northern New Mexico

    Science.gov (United States)

    Carol Raish

    1996-01-01

    The entrance of the Spanish into what is now New Mexico in the 1500s permanently altered aboriginal land use and subsistence patterns by the introduction of domesticated animals such as horses, cattle. sheep, goats, and pigs. During the Spanish Colonial and Mexican periods, both the Puebloan groups and the Hispanic settlers practiced mixed farming featuring small...

  14. Use of scanning electron microscopy to confirm the identity of lice infesting communally grazed goat herds

    OpenAIRE

    P.J. Sebei; C.M.E. McCrindle; E.D. Green; M.L. Turner

    2004-01-01

    Lice have been described on goats in commercial farming systems in South Africa but not from flocks on communal grazing. During a longitudinal survey on the causes of goat kid mortality, conducted in Jericho district, North West Province, lice were collected from communally grazed indigenous goats. These lice were prepared for and viewed by scanning electron microscopy, and micromorphological taxonomic details are described. Three species of lice were found in the study area and identif...

  15. Herbaceous vegetation restoration potential and soil physical condition in a mountain grazing land of Eastern Tigray, Ethiopia

    Directory of Open Access Journals (Sweden)

    Gebrewahd Amha Abesha

    2014-06-01

    Full Text Available An existence of information in the form database and full knowledge of grazing land vegetation resources and trend over time is essential for management decisions. This study was conducted in Kiltew -Awelaelo, eastern Tigray, Ethiopia. The study aimed to investigate species composition and diversity of the herbaceous vegetation, and examine the physical soil condition of the grazing lands. A total of 45 quadrats measuring 20m×20m (400m2 were laid out in 15 sample sites from three corresponding land use types (i.e. ten year enclosure, five year enclosure and open grazing land. From each land use type five sites having three quadrats were investigated. Each quadrat was laid out at an interval of 400m in five parallel transects each 200m apart from other. To collect data of herbaceous and soil five randomly located 1m2 area each, was selected and marked, within each 400m2 sample quadrat of sample sites located along the main transect. There was significant (PBracharia sp., Bromus pectinatus, Chloris gayana, Cenchurs cilarias, chloris radiata, Cynodon dactylon, Dactyloctenium aegyptium, Digitaria Velutina, Eragrostis teniufolia, Lintonia nutans, Setaria pumila, Seteria verticillate, and Tragus racemosus all occurred frequently forming the major constituents of the sites. Therefore, regeneration from area enclosure can be on advocated practice for grazing lands rehabilitation.

  16. Pastoralists in a changing environment: The competition for grazing land in and around the W Biosphere Reserve, Benin Republic.

    Science.gov (United States)

    Tamou, Charles; Ripoll-Bosch, Raimon; de Boer, Imke J M; Oosting, Simon J

    2018-04-01

    Pastoralists face increasing competition for land with crop farmers and nature in and around the W Biosphere Reserve (WBR) in Benin. Our aim was to describe and analyse land use changes in order to understand their drivers, and to describe and analyse the viewpoints of relevant stakeholders in order to understand the competition for land. To this end, remote sensing data, regional statistics, and survey data were collected. We found that crop land expansion around the WBR was the direct driver of decrease of the grazing land area. Population growth and rising demand for food crops, and government support to the cotton sector were indirect drivers of grazing land reduction. Furthermore, competing claims on land among users arose from the complex interaction of crop expansion, presence of WBR and the way it is governed, the lack of support to pastoralists, and the increasing shift of pastoralists' lifestyle into one of settled crop farmers. Pastoralism is under threat and its survival depends on the successful implementation of policies to support pastoralists and protect grazing lands.

  17. Channeling effect in electronic spectra produced by grazing impact of fast protons on insulator surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Archubi, C D; Gravielle, M S, E-mail: archubi@iafe.uba.a, E-mail: msilvia@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428, Buenos Aires (Argentina)

    2009-11-01

    Electron emission due to grazing scattering of fast protons from LiF and KCl surfaces is studied under axial incidence conditions. The differential emission probability is calculated within a distorted-wave formalism, taking into account axial channeled trajectories. For different emission angles, electronic spectra for proton incidence along the two principal crystal axes ([100] and [110]) are compared with those corresponding to an impact velocity in a random direction, finding effects associated with the channeling conditions.

  18. Western land managers will need all available tools for adapting to climate change, including grazing: a critique of Beschta et al.

    Science.gov (United States)

    Svejcar, Tony; Boyd, Chad; Davies, Kirk; Madsen, Matthew; Bates, Jon; Sheley, Roger; Marlow, Clayton; Bohnert, David; Borman, Mike; Mata-Gonzàlez, Ricardo; Buckhouse, John; Stringham, Tamzen; Perryman, Barry; Swanson, Sherman; Tate, Kenneth; George, Mel; Ruyle, George; Roundy, Bruce; Call, Chris; Jensen, Kevin; Launchbaugh, Karen; Gearhart, Amanda; Vermeire, Lance; Tanaka, John; Derner, Justin; Frasier, Gary; Havstad, Kris

    2014-06-01

    In a previous article, Beschta et al. (Environ Manag 51(2):474-491, 2013) argue that grazing by large ungulates (both native and domestic) should be eliminated or greatly reduced on western public lands to reduce potential climate change impacts. The authors did not present a balanced synthesis of the scientific literature, and their publication is more of an opinion article. Their conclusions do not reflect the complexities associated with herbivore grazing. Because grazing is a complex ecological process, synthesis of the scientific literature can be a challenge. Legacy effects of uncontrolled grazing during the homestead era further complicate analysis of current grazing impacts. Interactions of climate change and grazing will depend on the specific situation. For example, increasing atmospheric CO₂ and temperatures may increase accumulation of fine fuels (primarily grasses) and thus increase wildfire risk. Prescribed grazing by livestock is one of the few management tools available for reducing fine fuel accumulation. While there are certainly points on the landscape where herbivore impacts can be identified, there are also vast grazed areas where impacts are minimal. Broad scale reduction of domestic and wild herbivores to help native plant communities cope with climate change will be unnecessary because over the past 20-50 years land managers have actively sought to bring populations of native and domestic herbivores in balance with the potential of vegetation and soils. To cope with a changing climate, land managers will need access to all available vegetation management tools, including grazing.

  19. Use of scanning electron microscopy to confirm the identity of lice infesting communally grazed goat herds

    Directory of Open Access Journals (Sweden)

    P.J. Sebei

    2004-11-01

    Full Text Available Lice have been described on goats in commercial farming systems in South Africa but not from flocks on communal grazing. During a longitudinal survey on the causes of goat kid mortality, conducted in Jericho district, North West Province, lice were collected from communally grazed indigenous goats. These lice were prepared for and viewed by scanning electron microscopy, and micromorphological taxonomic details are described. Three species of lice were found in the study area and identified as Bovicola caprae, Bovicola limbatus and Linognathus africanus. Sucking and biting lice were found in ten of the 12 herds of goats examined. Lice were found on both mature goats and kids. Bovicola caprae and L. africanus were the most common biting and sucking lice respectively in all herds examined. Scanning electron microscopy revealed additional features which aided in the identification of the louse species. Photomicrographs were more accurate aids to identification than the line drawings in the literature and facilitated identification using dissecting microscope.

  20. Use of scanning electron microscopy to confirm the identity of lice infesting communally grazed goat herds.

    Science.gov (United States)

    Sebei, P J; McCrindle, C M E; Green, E D; Turner, M L

    2004-06-01

    Lice have been described on goats in commercial farming systems in South Africa but not from flocks on communal grazing. During a longitudinal survey on the causes of goat kid mortality, conducted in Jericho district, North West Province, lice were collected from communally grazed indigenous goats. These lice were prepared for and viewed by scanning electron microscopy, and micro-morphological taxonomic details are described. Three species of lice were found in the study area and identified as Bovicola caprae, Bovicola limbatus and Linognathus africanus. Sucking and biting lice were found in ten of the 12 herds of goats examined. Lice were found on both mature goats and kids. Bovicola caprae and L. africanus were the most common biting and sucking lice respectively in all herds examined. Scanning electron microscopy revealed additional features which aided in the identification of the louse species. Photomicrographs were more accurate aids to identification than the line drawings in the literature and facilitated identification using dissecting microscope.

  1. Electron emission and energy loss in grazing collisions of protons with insulator surfaces

    International Nuclear Information System (INIS)

    Gravielle, M. S.; Miraglia, J. E.; Aldazabal, I.; Arnau, A.; Ponce, V. H.; Aumayr, F.; Lederer, S.; Winter, H.

    2007-01-01

    Electron emission from LiF, KCl, and KI crystal surfaces during grazing collisions of swift protons is studied using a first-order distorted-wave formalism. Owing to the localized character of the electronic structure of these surfaces, we propose a model that allows us to describe the process as a sequence of atomic transitions from different target ions. Experimental results are presented for electron emission from LiF and KI and energy loss from KI surfaces. Calculations show reasonable agreement with these experimental data. The role played by the charge of the incident particle is also investigated

  2. Electron emission induced by resonant coherent ion-surface interaction at grazing incidence

    International Nuclear Information System (INIS)

    Garcia de Abajo, F.J.; Ponce, V.H.; Echenique, P.M.

    1992-01-01

    A new spectroscopy based on the resonant coherently induced electron loss to the continuum in ion-surface scattering under grazing incidence is proposed. A series of peaks, corresponding to the energy differences determined by the resonant interaction with the rows of atoms in the surface, is predicted to appear in the energy distribution of electrons emitted from electronic states bound to the probe. Calculations for MeV He + ions scattered at a W(001) surface along the left-angle 100 right-angle direction with a glancing angle of 0--2 mrad show a total yield close to 1

  3. Distribution of lithium in agricultural and grazing land soils at European continental scale (GEMAS project)

    Science.gov (United States)

    Negrel, Philippe; Reimann, Clemens; Ladenberger, Anna; Birke, Manfred

    2017-04-01

    The environmental chemistry of Li has received attention because Li has been shown to have numerous and important implications for human health and agriculture and the stable isotope composition of lithium is a powerful geochemical tool that provides quantitative information about Earth processes such as sediment recycling, global chemical weathering and its role in the carbon cycle, hydrothermal alteration, and groundwater evolution. However, the role of bedrock sources, weathering and climate changes in the repartition of Li at the continental scale has been scarcely investigated. Agricultural soil (Ap-horizon, 0-20 cm) and grazing land soil (Gr-horizon, 0-10 cm) samples were collected from a large part of Europe (33 countries, 5.6 million km2) as a part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil mapping project. GEMAS soil data have been used to provide a general view of element mobility and source rocks at the continental scale, either by reference to average crustal abundances or to normalized patterns of element mobility during weathering processes. The survey area includes a diverse group of soil parent materials with varying geological history, a wide range of climate zones and landscapes. The concentrations of Li in European soil were determined by ICP-MS after a hot aqua regia extraction, and their spatial distribution patterns generated by means of a GIS software. Due to the partial nature of the aqua regia extraction, the mean concentration of Li in the European agricultural soil (ca 11.4 mg/kg in Ap and Gr soils) is about four times lower than in the Earth's upper continental crust (UCC = 41 mg/kg). The combined plot histogram - density trace one- dimensional scattergram - boxplot of the aqua regia data displays the univariate data distribution of Li. The one-dimensional scattergram and boxplot highlight the existence of many outliers at the lower end of the Li distribution and very few at the upper end. Though the

  4. Tests of a grazing-incidence ring resonator free-electron laser

    International Nuclear Information System (INIS)

    Dowell, D.H.; Laucks, M.L.; Lowrey, A.R.; Adamski, J.L.; Pistoresi, D.J.; Shoffstall, D.R.; Bentz, M.P.; Burns, R.H.; Guha, J.; Sun, K.; Tomita, W.

    1991-01-01

    This paper reports on the Boeing free-electron laser (FEL) optical cavity that has been changed from a simple concentric cavity using two spherical mirrors to a larger grazing-incidence ring resonator. The new resonator consists of two mirror telescopes located at each end of the wiggler with a round-trip path length of approximately 133 m. Each telescope is a grazing-incidence hyperboloid followed by a normal-incidence paraboloid. Initial tests showed that poorly positioned ring focus and unreliable pointing alignment resulted in reduced and structured FEL output. (First lasing operation occurred on March 23 and 24, 1990.) Later efforts concentrated on improving the resonator alignment techniques and lowering the single-pass losses. FEL performance and reliability have significantly improved due to better ring alignment. The alignment procedure and recent lasing results are described. The effect the electron beam has on lasing is also discussed. Measurements are presented showing how FEL temporal output and wavelength are sensitive to electron beam energy variations

  5. Rangeland Brush Estimation Toolbox (RaBET): An Approach for Evaluating Brush Management Conservation Efforts in Western Grazing Lands

    Science.gov (United States)

    Holifield Collins, C.; Kautz, M. A.; Skirvin, S. M.; Metz, L. J.

    2016-12-01

    There are over 180 million hectares of rangelands and grazed forests in the central and western United States. Due to the loss of perennial grasses and subsequent increased runoff and erosion that can degrade the system, woody cover species cannot be allowed to proliferate unchecked. The USDA-Natural Resources Conservation Service (NRCS) has allocated extensive resources to employ brush management (removal) as a conservation practice to control woody species encroachment. The Rangeland-Conservation Effects Assessment Project (CEAP) has been tasked with determining how effective the practice has been, however their land managers lack a cost-effective means to conduct these assessments at the necessary scale. An ArcGIS toolbox for generating large-scale, Landsat-based, spatial maps of woody cover on grazing lands in the western United States was developed through a collaboration with NRCS Rangeland-CEAP. The toolbox contains two main components of operation, image generation and temporal analysis, and utilizes simple interfaces requiring minimum user inputs. The image generation tool utilizes geographically specific algorithms developed from combining moderate-resolution (30-m) Landsat imagery and high-resolution (1-m) National Agricultural Imagery Program (NAIP) aerial photography to produce the woody cover scenes at the Major Land Resource (MLRA) scale. The temporal analysis tool can be used on these scenes to assess treatment effectiveness and monitor woody cover reemergence. RaBET provides rangeland managers an operational, inexpensive decision support tool to aid in the application of brush removal treatments and assessing their effectiveness.

  6. Influence of grazing and land use on stream-channel characteristics among small dairy farms in the Eastern United States

    Science.gov (United States)

    Brand, Genevieve; Vondracek, Bruce C.; Jordan, Nicholas R.

    2015-01-01

    Rotational grazing (RG) is a livestock management practice that rotates grazing cattle on a scale of hours to days among small pastures termed paddocks. It may beneficially affect stream channels, relative to other livestock management practices. Such effects and other beneficial effects on hydrology are important to RG's potential to provide a highly multifunctional mode of livestock farming. Previous comparisons of effects of RG and confinement dairy (CD) on adjoining streams have been restricted in scale and scope. We examined 11 stream-channel characteristics on a representative sample of 37 small dairy farms that used either RG or CD production methods. Our objectives were: (1) to compare channel characteristics on RG and CD farms, as these production methods are implemented in practice, in New York, Pennsylvania and Wisconsin, USA; and (2) to examine land use on these farms that may affect stream-channel characteristics. To help interpret channel characteristic findings, we examined on-farm land use in riparian areas 50 m in width along both sides of stream reaches and whole-farm land use. In all states, stream-channel characteristics on RG and CD farms did not differ. Whole-farm land use differed significantly between farm types; CD farms allocated more land to annual row crops, whereas RG farms allocated more land to pasture and grassland. However, land cover in 50 m riparian areas was not different between farm types within states; in particular, many RG and CD farms had continuously grazed pastures in riparian areas, typically occupied by juvenile and non-lactating cows, which may have contributed sediment and nutrients to streams. This similarity in riparian management practices may explain the observed similarity of farm types with respect to stream-channel characteristics. To realize the potential benefits of RG on streams, best management practices that affect stream-channel characteristics, such as protection of riparian areas, may improve aggregate

  7. Espanola/Canjilon Pilot Study: Economic, social, and cultural aspects of public land grazing on the Santa Fe and Carson National Forests

    Science.gov (United States)

    Carol Raish

    1999-01-01

    Many of the livestock grazing permittees on the Carson and Santa Fe National Forests in northern New Mexico are descendants of Hispanic settlers who have farmed and ranched in the region for 400 years. Much of the permitted land was formerly owned or used by local communities under Spanish and Mexican land grants. Cultural differences and historical issues of...

  8. Electron emission induced by resonant coherent interaction in ion-surface scattering at grazing incidence

    International Nuclear Information System (INIS)

    Garcia de Abajo, F.J.; Ponce, V.H.; Echenique, P.M.

    1994-01-01

    The resonant coherent interaction of an ion with an oriented crystal surface, under grazing-incidence conditions with respect to a special direction of the crystal, gives rise to electron loss to the continuum from electronic bound states of the ion. The calculations presented below predict large probabilities for electron emission due to this mechanism. The electrons are emitted with well defined energies, expressed in terms of the condition of resonance. Furthermore, the emission takes place around certain preferential directions, which are determined by both the latter condition and the symmetry of the surface lattice. Our calculations for MeV He + ions scattered at a W(001) surface along the left-angle 100 right-angle direction with glancing angle of 0--2 mrad indicate a yield of emission close to 1. Using heavier projectiles, one obtains smaller yields, but still large enough to be measurable in some cases (e.g., ∼0.9 for 53 MeV B 4+ and an angle of incidence of 1 mrad). Besides, the initial bound state is energy shifted due to the interaction with both the crystal potential and the velocity-dependent image potential. This results in a slight shift of the peaks of emission, which suggests a possible spectroscopy for analyzing the dynamical interaction of electronic bound states with solid surfaces

  9. Institutions, sustainable land use and consumer welfare: the case of forest and grazing lands in northern Ethiopia

    NARCIS (Netherlands)

    Gebreegziabher, Z.; Gabremedhin, B.; Mekonnen, A.

    2012-01-01

    Land is an essential factor of production. Institutions that govern its efficient use determine the sustainability of this essential resource. In Ethiopia all land is publicly owned. Such an institutional setting is said to have resulted in the major degradation of Ethiopia's land resources and

  10. Optical Analysis of Grazing Incidence Ring Resonators for Free-Electron Lasers

    Science.gov (United States)

    Gabardi, David Richard

    1990-08-01

    The design of resonators for free-electron lasers (FELs) which are to operate in the soft x-ray/vacuum ultraviolet (XUV) region of the spectrum is complicated by the fact that, in this wavelength regime, normal incidence mirrors, which would otherwise be used for the construction of the resonators, generally have insufficient reflectivities for this purpose. However, the use of grazing incidence mirrors in XUV resonators offers the possibility of (1) providing sufficient reflectivity, (2) a lessening of the mirrors' thermal loads due to the projection of the laser beam onto an oblique surface, and (3) the preservation of the FEL's tunability. In this work, the behavior of resonators employing grazing incidence mirrors in ring type configurations is explored. In particular, two designs, each utilizing four off-axis conic mirrors and a number of flats, are examined. In order to specify the location, orientation, and surface parameters for the mirrors in these resonators, a design algorithm has been developed based upon the properties of Gaussian beam propagation. Two computer simulation methods are used to perform a vacuum stability analysis of the two resonator designs. The first method uses paraxial ray trace techniques with the resonators' thin lens analogues while the second uses the diffraction-based computer simulation code GLAD (General Laser Analysis and Design). The effects of mirror tilts and deviations in the mirror surface parameters are investigated for a number of resonators designed to propagate laser beams of various Rayleigh ranges. It will be shown that resonator stability decreases as the laser wavelength for which the resonator was designed is made smaller. In addition, resonator stability will also be seen to decrease as the amount of magnification the laser beam receives as it travels around the resonator is increased.

  11. A method to the impact assessment of the returning grazing land to grassland project on regional eco-environmental vulnerability

    International Nuclear Information System (INIS)

    Shao, Huaiyong; Sun, Xiaofei; Wang, Haoxue; Zhang, Xiaoxue; Xiang, Zhiying; Tan, Rui; Chen, Xuanyi; Xian, Wei; Qi, Jiaguo

    2016-01-01

    The Chinese government has conducted the Returning Grazing Land to Grassland Project (RGLGP) across large portions of grasslands from western China since 2003. In order to explore and understand the impact in the grassland's eco-environment during the RGLGP, we utilized Projection Pursuit Model (PPM) and Geographic Information System (GIS) to develop a spatial assessment model to examine the ecological vulnerability of the grassland. Our results include five indications: (1) it is practical to apply the spatial PPM on ecological vulnerability assessment for the grassland. This methodology avoids creating an artificial hypothesis, thereby providing objective results that successfully execute a multi-index assessment process and analysis under non-linear systems in eco-environments; (2) the spatial PPM is not only capable of evaluating regional eco-environmental vulnerability in a quantitative way, but also can quantitatively demonstrate the degree of effect in each evaluation index for regional eco-environmental vulnerability; (3) the eco-environment of the Xianshui River Basin falls into the medium range level. The normalized difference vegetation index (NDVI) and land use cover and change (LUCC) crucially influence the Xianshui River Basin's eco-environmental vulnerability. Generally, in the Xianshui River Basin, regional eco-environmental conditions improved during 2000 and 2010. The RGLGP positively affected NDVI and LUCC structure, thereby promoting the enhancement of the regional eco-environment; (4) the Xianshui River Basin divides its ecological vulnerability across different levels; therefore our study investigates three ecological regions and proposes specific suggestions for each in order to assist in eco-environmental protection and rehabilitation; and lastly that (5) the spatial PPM established by this study has the potential to be applied on all types of grassland eco-environmental vulnerability assessments under the RGLGP and under the similar

  12. A method to the impact assessment of the returning grazing land to grassland project on regional eco-environmental vulnerability

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Huaiyong, E-mail: huaiyongshao@163.com [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, MI (United States); Sun, Xiaofei; Wang, Haoxue; Zhang, Xiaoxue [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Xiang, Zhiying [School of Earth Sciences, Zhejiang University, Hangzhou 310027, Zhejiang (China); Tan, Rui; Chen, Xuanyi [Key Laboratory of Geoscience Spatial Information Technology, Ministry of Land and Resources of China, Chengdu University of Technology, Chengdu 610059, Sichuan (China); Xian, Wei [College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, Sichuan (China); Qi, Jiaguo [Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, MI (United States)

    2016-01-15

    The Chinese government has conducted the Returning Grazing Land to Grassland Project (RGLGP) across large portions of grasslands from western China since 2003. In order to explore and understand the impact in the grassland's eco-environment during the RGLGP, we utilized Projection Pursuit Model (PPM) and Geographic Information System (GIS) to develop a spatial assessment model to examine the ecological vulnerability of the grassland. Our results include five indications: (1) it is practical to apply the spatial PPM on ecological vulnerability assessment for the grassland. This methodology avoids creating an artificial hypothesis, thereby providing objective results that successfully execute a multi-index assessment process and analysis under non-linear systems in eco-environments; (2) the spatial PPM is not only capable of evaluating regional eco-environmental vulnerability in a quantitative way, but also can quantitatively demonstrate the degree of effect in each evaluation index for regional eco-environmental vulnerability; (3) the eco-environment of the Xianshui River Basin falls into the medium range level. The normalized difference vegetation index (NDVI) and land use cover and change (LUCC) crucially influence the Xianshui River Basin's eco-environmental vulnerability. Generally, in the Xianshui River Basin, regional eco-environmental conditions improved during 2000 and 2010. The RGLGP positively affected NDVI and LUCC structure, thereby promoting the enhancement of the regional eco-environment; (4) the Xianshui River Basin divides its ecological vulnerability across different levels; therefore our study investigates three ecological regions and proposes specific suggestions for each in order to assist in eco-environmental protection and rehabilitation; and lastly that (5) the spatial PPM established by this study has the potential to be applied on all types of grassland eco-environmental vulnerability assessments under the RGLGP and under the

  13. 7 CFR 760.305 - Eligible grazing losses.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Eligible grazing losses. 760.305 Section 760.305... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... period for the specific type of grazing land or pastureland for the county.) (b) A grazing loss is not...

  14. The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

    Science.gov (United States)

    An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosio...

  15. Extreme phosphorus losses in drainage from grazed dairy pastures on marginal land.

    Science.gov (United States)

    McDowell, Richard W; Monaghan, Ross M

    2015-03-01

    With the installation of artificial drainage and large inputs of lime and fertilizer, dairy farming can be profitable on marginal land. We hypothesized that this will lead to large phosphorus (P) losses and potential surface water impairment if the soil has little capacity to sorb added P. Phosphorous was measured in drainage from three "marginal" soils used for dairying: an Organic soil that had been developed out of scrub for 2 yr and used for winter forage cropping, a Podzol that had been developed into pasture for 10 yr, and an intergrade soil that had been in pasture for 2 yr. Over 18 mo, drainage was similar among all sites (521-574 mm), but the load leached to 35-cm depth from the Organic soil was 87 kg P ha (∼89% of fertilizer-P added); loads were 1.7 and 9.0 kg ha from the Podzol and intergrade soils, respectively. Soil sampling to 100 cm showed that added P leached throughout the Organic soil profile but was stratified and enriched in the top 15 cm of the Podzol. Poor P sorption capacity (<5%) in the Organic soil, measured as anion storage capacity, and tillage (causing mineralization and P release) in the Organic and intergrade soils were thought to be the main causes of high P loss. It is doubtful that strategies would successfully mitigate these losses to an environmentally acceptable level. However, anion storage capacity could be used to identify marginal soils with high potential for P loss for the purpose of managing risk. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  16. A critical analysis of the long-term impact (1936-2015) of grazing management on Land Degradation in a marginal, rural community of Southern Italy

    Science.gov (United States)

    Quaranta, Giovanni; Salvia, Rosanna; De Paola, Velia; Coluzzi, Rosa; Imbrenda, Vito; Simoniello, Tiziana

    2017-04-01

    Unsustainable grazing, one of the most diffused problem in land management at the global scale, is considered as a serious pressure on natural landscapes. Particularly in the Mediterranean agroforestry landscapes, unsustainable grazing is regarded as a key factor of degradation processes, mostly determined and exacerbated by evolving socioeconomic and environmental conditions at the local scale, revised agricultural policies and changing international market scenario. The Common Agricultural Policy set at the European level plays a powerful and twofold role in shaping the dynamics at local level. Measures adopted for Less Favoured Areas, for example, have stimulated grazing intensification based on financial supports whose effectiveness is shaped by the socioeconomic local context. At the same time, pasture-based livestock farming systems are considered priority habitats preserving traditional and high natural value farmlands in Mediterranean Europe. A sustainable management of pastures may also contribute to limit soil erosion and to mitigate land degradation. This paper critically analyses the drivers of change and the challenges facing a Mediterranean upland pastoralist systems in Southern Italy along a period of almost 80 years (1936-2015). The detailed case study highlights the linkages between the evolution of landscape, grazing management, locally adapted animal breeds and social capital. Historical forest maps, aerial imagery and satellite data at different spatial resolutions have been used to trace land use trajectories occurred during the investigated period within the study area. The integration in a GIS environment of the obtained results with diachronic detailed farm management surveys and semi-structured interviews, shows a strong link between land use changes and economic performances mainly connected to policy orientation. Along the time period considered, different adaptation strategies adopted by local actors are analysed leading to the present

  17. Grass composition and rangeland condition of the major grazing ...

    African Journals Online (AJOL)

    One area represented lightly grazed government ranches or parks which were used as benchmarks, another area represented the seasonal grazing areas with an intermediate grazing pressure and the remaining were the heavily grazed roadsides, lakeshores and other communal grazing lands. The range condition ...

  18. Software Development Framework For Electronic Land Titles ...

    African Journals Online (AJOL)

    Record keeping is a fundamental activity of public administration. Land Titles management in Nigeria, by virtue of the Land use act 1990, is one of the functions of government. Most of the records hitherto used in managing the records of lands are documented on paper. We carried out an investigation into the suitability of ...

  19. Synthetic Constraint of Ecosystem C Models Using Radiocarbon and Net Primary Production (NPP) in New Zealand Grazing Land

    Science.gov (United States)

    Baisden, W. T.

    2011-12-01

    Time-series radiocarbon measurements have substantial ability to constrain the size and residence time of the soil C pools commonly represented in ecosystem models. Radiocarbon remains unique in the ability to constrain the large stabilized C pool with decadal residence times. Radiocarbon also contributes usefully to constraining the size and turnover rate of the passive pool, but typically struggles to constrain pools with residence times less than a few years. Overall, the number of pools and associated turnover rates that can be constrained depends upon the number of time-series samples available, the appropriateness of chemical or physical fractions to isolate unequivocal pools, and the utility of additional C flux data to provide additional constraints. In New Zealand pasture soils, we demonstrate the ability to constrain decadal turnover times with in a few years for the stabilized pool and reasonably constrain the passive fraction. Good constraint is obtained with two time-series samples spaced 10 or more years apart after 1970. Three or more time-series samples further improve the level of constraint. Work within this context shows that a two-pool model does explain soil radiocarbon data for the most detailed profiles available (11 time-series samples), and identifies clear and consistent differences in rates of C turnover and passive fraction in Andisols vs Non-Andisols. Furthermore, samples from multiple horizons can commonly be combined, yielding consistent residence times and passive fraction estimates that are stable with, or increase with, depth in different sites. Radiocarbon generally fails to quantify rapid C turnover, however. Given that the strength of radiocarbon is estimating the size and turnover of the stabilized (decadal) and passive (millennial) pools, the magnitude of fast cycling pool(s) can be estimated by subtracting the radiocarbon-based estimates of turnover within stabilized and passive pools from total estimates of NPP. In grazing

  20. Livestock grazing, wildlife habitat, and rangeland values

    Science.gov (United States)

    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...

  1. Angle resolved electron spectroscopy of spontaneous ionization processes occurring in doubly charged ion-surface collisions at grazing incidence

    International Nuclear Information System (INIS)

    Wouters, P.A.A.F.; Emmichoven, P.A.Z. van; Niehaus, A.

    1989-01-01

    The experimental setup used to measure electron spectra at well defined detection angles for grazing incidence doubly charged ion-surface collisions at keV-energies is described. Electron spectra are reported for the rare gas ions colliding with a Cu(110)-surface. The spectra are analyzed in terms of various spontaneous ionization processes using a newly developed model. It is found that double capture followed by atomic auto-ionization on the incoming trajectory and Auger-capture processes in which the first and second hole in the doubly charged projectiles are successively filled are the main processes contributing to the electron spectra. From a comparison of model calculations with measured spectra it is concluded that the metal electrons cannot adapt adiabatically to the sudden changes of the charge state of the projectile in front of the surface. A parameter characterizing the partly diabatic behavior is determined. The variation of spectra upon adsorption of a monolayer of oxygen on the surface is reported and discussed. (author)

  2. Vicinage effects in energy loss and electron emission during grazing scattering of heavy molecular ions from a solid surface

    International Nuclear Information System (INIS)

    Song Yuanhong; Wang Younian; Miskovic, Z.L.

    2005-01-01

    Vicinage effects in the energy loss and the electron emission spectra are studied in the presence of Coulomb explosion of swift, heavy molecular ions, during their grazing scattering from a solid surface. The dynamic response of the surface is treated by means of the dielectric theory within the specular reflection model using the plasmon pole approximation for the bulk dielectric function, whereas the angle-resolved energy spectra of the electrons emitted from the surface are obtained on the basis of the first-order, time-dependent perturbation theory. The evolution of the charge states of the constituent ions in the molecule during scattering is described by a nonequilibrium extension of the Brandt-Kitagawa model. The molecule scattering trajectories and the corresponding Coulomb explosion dynamics are evaluated for the cases of the internuclear axis being either aligned in the beam direction or randomly oriented in the directions parallel to the surface. Our calculations show that the vicinage effect in the energy loss is generally weaker for heavy molecules than for light molecules. In addition, there is clear evidence of the negative vicinage effect in both the energy loss and the energy spectra of the emitted electrons for molecular ions at lower speeds and with the axis aligned in the direction of motion

  3. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Science.gov (United States)

    2010-04-01

    ... § 166.307 Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not... trust or non-trust rangeland in common with the permitted land. Grazing capacity will be established... 25 Indians 1 2010-04-01 2010-04-01 false Will the grazing capacity be increased if I graze...

  4. Nonlinear Changes in Land Cover and Sediment Runoff in a New Zealand Catchment Dominated by Plantation Forestry and Livestock Grazing

    Directory of Open Access Journals (Sweden)

    Ioannis Kamarinas

    2016-10-01

    Full Text Available Land cover can change frequently on intensively managed landscapes, affecting water quality across different spatiotemporal scales. Multi-resolution datasets are necessary in order to assess the extent and trends of these changes, as well as potential cross-scale interactions. In this study, both spatial and temporal analyses of land disturbance (i.e., soil exposure from vegetation removal and water quality were performed on datasets ranging from daily to yearly time scales. Time-series analyses of land disturbance were compared against the water quality variables of total suspended solids (TSS, turbidity, and visual clarity for the Hoteo River catchment on the North Island of New Zealand for the 2000–2013 period. During forest harvest and recovery phases, exotic forests were the dominant disturbance, up to five times the area of grassland disturbance; while after recovery, grasslands assumed the dominant role, for up to 16 times the area of forest disturbance. Time-series of TSS from field sampling (2000–2013 and TSS-event analyses (2012–2014 displayed distinct nonlinear patterns, suggesting that after major events, sediment that is stored in the landscape is exhausted and a period of sediment build-up follows until the next major event. Time-series analyses also showed a connection between trends in connected land disturbance and visual water clarity, with connected disturbance having the potential to be a water quality indicator. Future research should be conducted at even finer spatiotemporal scales over longer periods in order to identify effects of localized land disturbances on downstream water quality.

  5. 75 FR 29572 - Information Collection; Grazing Management

    Science.gov (United States)

    2010-05-26

    ... Control Number 1004-0019] Information Collection; Grazing Management AGENCY: Bureau of Land Management... submitted an information collection request to the Office of Management and Budget (OMB) for a 3-year... INFORMATION: Title: Grazing Management (43 CFR 4120). OMB Number: 1004-0019. Forms: 4120-6 (Cooperative Range...

  6. 36 CFR 222.53 - Grazing fees in the East-noncompetitive procedures.

    Science.gov (United States)

    2010-07-01

    ... lands and the total costs (other than grazing fee costs) of operating on National Forest System lands... the percentage change in the cost of alternative livestock feed. (3) Computation of Annual Grazing Fee... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing fees in the East...

  7. Na and K Levels in forage species from the communal grazing lands during the dry season at some locations in the Northern Region of Ghana

    International Nuclear Information System (INIS)

    Gomda, Y.M.; Osae, E.K.; Akaho, E.H.K.; Fianu, F.K.; Karbo, N.

    1999-04-01

    Forage species were taken, during the dry season, from five districts in the Northern Region of Ghana and analysed for Na and K using the Neutron Activation Analysis (NAA) technique. The Na level varied in plants species as well as location. The level ranged between 0.049 g/kg DM and 1.14 g/kg DM. This was found to be inadequate for the animals and require supplementation during the dry season. Potassium level in the forage species was between 7.8 to 91.3g/kg DM and appeared to be adequate for the grazing animals. (author)

  8. Grazing incidence beam expander

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Crystal and electronic structures of pentacene thin films from grazing-incidence x-ray diffraction and first-principles calculations

    International Nuclear Information System (INIS)

    Nabok, Dmitrii; Puschnig, Peter; Ambrosch-Draxl, Claudia; Werzer, Oliver; Resel, Roland; Smilgies, Detlef-M.

    2007-01-01

    Combined experimental and theoretical investigations on thin films of pentacene are performed in order to determine the structure of the pentacene thin film phase. Grazing incidence x-ray diffraction is used for studying a pentacene thin film with a nominal thickness of 180 nm. The crystal structure is found to exhibit the lattice parameters a=0.592 nm, b=0.754 nm, c=1.563 nm, α=81.5 deg. , β=87.2 deg. , and γ=89.9 deg. . These crystallographic unit cell dimensions are used as the only input parameters for ab initio total-energy calculations within the framework of density functional theory revealing the molecular packing within the crystal structure. Moreover, we calculate the electronic band structure of the thin film phase and compare it to that of the bulk phase. We find the intermolecular bandwidths of the thin film phase to be significantly larger compared to the bulk structure, e.g., the valence bandwidth is twice as large. This remarkable effect is traced back to an enhanced intermolecular π-π overlap due to the upright standing molecules in the thin film phase

  10. Grazing lands in Sub-Saharan Africa and their potential role in climate change mitigation: What we do and don’t know

    Science.gov (United States)

    Grazinglands cover much of sub-Saharan Africa. When well-managed, these lands provide a wide variety of ecosystem services, many of which are positively correlated with increase in soil carbon. Pastoralists and other land managers are currently rewarded primarily for the production of animal product...

  11. Na and K Levels in forage species from the communal grazing lands during the dry season at some locations in the Northern Region of Ghana

    Energy Technology Data Exchange (ETDEWEB)

    Gomda, Y M; Osae, E K; Akaho, E H.K. [Ghana Atomic Energy Commission, Accra (Ghana); Fianu, F K [University of Ghana, Legon, Accra, (Ghana); Karbo, N [Animal Research Institute, Nyankpala (Ghana)

    1999-09-01

    Forage species were taken, during the dry season, from five districts in the Northern Region of Ghana and analysed for Na and K using the Neutron Activation Analysis (NAA) technique. The Na level varied in plants species as well as location. The level ranged between 0.049 g/kg DM and 1.14 g/kg DM. This was found to be inadequate for the animals and require supplementation during the dry season. Potassium level in the forage species was between 7.8 to 91.3g/kg DM and appeared to be adequate for the grazing animals. (author) Technical report for year ending 1998. 2 tabs.; 18 refs.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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...

  14. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Science.gov (United States)

    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...

  15. Exploring Long-Term Impact of Grazing Management on Land Degradation in the Socio-Ecological System of Asteroussia Mountains, Greece

    Directory of Open Access Journals (Sweden)

    Costas Kosmas

    2015-07-01

    Full Text Available The socio-ecological system dominated by pastureland in the Asteroussia Mountains (Crete, Greece was analyzed over a long time interval (1945–2010 to identify the most relevant system’s characteristics and changes. Vegetation cover and land-uses have been quantified by analyzing aerial photographs exploring the whole study period. Soil characteristics have been assessed by carrying out an extensive field survey for the last reference year (2010 and by estimating the average soil loss for the past period using the PESERA soil erosion model validated by field measurements. Based on environmental, social and economic attributes, three major periods characterizing the socio-ecological system of Asteroussia Mountains have been distinguished. During the first and second period, the land was satisfactorily managed with moderate–low soil erosion rates despite the adverse (prevailing soil, topographic and climate conditions for vegetation growth. The third time interval featured a rapid growth in the livestock density causing increased soil erosion rates, loss in plant productivity, and a generalized over-exploitation of natural resources. As a consequence, the desertification process has significantly increased in the last period. The analysis of the long-term evolution of socio-ecological system provided evidence to understand the main drivers of land degradation and to recommend mitigation policies specifically addressing Mediterranean pastureland.

  16. Land

    NARCIS (Netherlands)

    C.A. Hunsberger (Carol); Tom P. Evans

    2012-01-01

    textabstractPressure on land resources has increased during recent years despite international goals to improve their management. The fourth Global Environment Outlook (UNEP 2007) highlighted the unprecedented land-use changes created by a burgeoning population, economic development and

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

    Science.gov (United States)

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

    2017-04-01

    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. © 2016 Society for Conservation Biology.

  18. Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales.

    Science.gov (United States)

    Monroe, Adrian P; Aldridge, Cameron L; Assal, Timothy J; Veblen, Kari E; Pyke, David A; Casazza, Michael L

    2017-06-01

    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. © 2017 by the Ecological Society of America.

  19. Study of electron anti-neutrinos associated with gamma-ray bursts using KamLAND

    NARCIS (Netherlands)

    Asakura, A.; Gando, A.; Gando, Y.; Hachiya, T.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, T.; Ishio, S.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obara, S.; Oki, Y.; Oura, T.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Tachibana, H.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B.D.; Yoshida, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T.I.; Berger, B.E.; Fujikawa, B.K.; O'Donnell, T.; Learned, J.G.; Maricic, J.; Sakai, M.; Winslow, L.A.; Efremenko, Y.; Karwowski, H.J.; Markoff, D.M.; Tornow, W.; Detwiler, J.A.; Enomoto, S.; Decowski, M.P.

    2015-01-01

    We search for electron anti-neutrinos (-Ve) from long- and short-duration gamma-ray bursts (GRBs) using data taken by the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) from 2002 August to 2013 June. No statistically significant excess over the background level is found. We place the

  20. Riparian Meadow Response to Modern Conservation Grazing Management

    Science.gov (United States)

    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.

  1. lands

    Directory of Open Access Journals (Sweden)

    A.T. O'Geen

    2015-04-01

    Full Text Available Groundwater pumping chronically exceeds natural recharge in many agricultural regions in California. A common method of recharging groundwater — when surface water is available — is to deliberately flood an open area, allowing water to percolate into an aquifer. However, open land suitable for this type of recharge is scarce. Flooding agricultural land during fallow or dormant periods has the potential to increase groundwater recharge substantially, but this approach has not been well studied. Using data on soils, topography and crop type, we developed a spatially explicit index of the suitability for groundwater recharge of land in all agricultural regions in California. We identified 3.6 million acres of agricultural land statewide as having Excellent or Good potential for groundwater recharge. The index provides preliminary guidance about the locations where groundwater recharge on agricultural land is likely to be feasible. A variety of institutional, infrastructure and other issues must also be addressed before this practice can be implemented widely.

  2. Woodlands Grazing Issues in Mediterranean Basin

    Science.gov (United States)

    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

  3. Land

    CSIR Research Space (South Africa)

    Audouin, M

    2007-01-01

    Full Text Available the factors contributing to desertification and practical measures necessary to combat desertification and mitigate the effect of drought. The priority issues reported on in this chapter are soil and veld degradation, and the loss of land for agricultural use....

  4. MRPC prototypes for NeuLAND tested using the single electron mode of ELBE/Dresden

    Energy Technology Data Exchange (ETDEWEB)

    Yakorev, Dmitry; Bemmerer, Daniel; Elekes, Zoltan; Kempe, Mathias; Stach, Daniel; Wagner, Andreas [Forschungszentrum Dresden-Rossendorf (FZD), Dresden (Germany); Aumann, Tom; Boretzky, Konstanze; Caesar, Christoph; Ciobanu, Mircea; Hehner, Joerg; Heil, Michael; Nusair, Omar; Reifarth, Rene; Simon, Haik [GSI, Darmstadt (Germany); Elvers, Michael; Maroussov, Vassili; Zilges, Andreas [Universitaet Koeln (Germany); Zuber, Kai [TU Dresden (Germany)

    2010-07-01

    The NeuLAND detector at the R{sup 3}B experiment at the future FAIR facility in Darmstadt aims to detect fast neutrons (0.2-1.0 GeV) with high time and spatial resolutions ({sigma}{sub t}<100 ps, {sigma}{sub x,y,z}<1 cm). Prototypes for the NeuLAND detector have been built at FZD and GSI and then studied using the 32 MeV pulsed electron beam at the superconducting electron accelerator ELBE in Dresden, Germany. Owing to the new, single-electron per bunch mode of operation, a rapid validation of the design criteria ({>=}90% efficiency for minimum ionizing particles, {sigma} {<=} 100 ps time resolution) was possible. Tested properties of the prototypes include glass thickness, spacing of the central anode, and a comparison of single-ended and differential readout. Tested frontend electronics schemes include FOPI (single-ended), PADI-based (both single-ended and differential mode tested), and ALICE (differential).

  5. Using NDVI to estimate carbon fluxes from small rotationally grazed pastures

    Science.gov (United States)

    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. However, the usefulness of satellite-based images for monitoring rotationally-grazed pastures in the northea...

  6. Habitat preference of geese is affected by livestock grazing : Seasonal variation in an experimental field evaluation

    NARCIS (Netherlands)

    Mandema, Freek S.; Tinbergen, Joost M.; Stahl, Julia; Esselink, Peter; Bakker, Jan P.

    The number of staging geese in northwestern Europe has increased dramatically. Growing goose numbers put strong grazing pressure on agricultural pastures. Damage to agricultural land may be mitigated by managing nature reserves in order to optimally accommodate large numbers of grazing geese.

  7. Study of Electron Anti-neutrinos Associated with Gamma-Ray Bursts Using KamLAND

    Science.gov (United States)

    Asakura, K.; Gando, A.; Gando, Y.; Hachiya, T.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, T.; Ishio, S.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obara, S.; Oki, Y.; Oura, T.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Tachibana, H.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yoshida, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Learned, J. G.; Maricic, J.; Sakai, M.; Winslow, L. A.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.; KamLAND Collaboration

    2015-06-01

    We search for electron anti-neutrinos ({{\\bar{ν }}e}) from long- and short-duration gamma-ray bursts (GRBs) using data taken by the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) from 2002 August to 2013 June. No statistically significant excess over the background level is found. We place the tightest upper limits on {{\\bar{ν }}e} fluence from GRBs below 7 MeV and place first constraints on the relation between {{\\bar{ν }}e} luminosity and effective temperature.

  8. Insect herbivory and vertebrate grazing impact food limitation and grasshopper populations during a severe outbreak

    Science.gov (United States)

    Interspecific competition between distantly related herbivores, as well as between large vertebrate herbivores and phytophagous insects, has received little attention. Livestock grazing is the dominant land use in western North American grasslands, where phytophagous insects can be the dominant herb...

  9. Biomass requirements from natural pastures for livestock grazing ...

    African Journals Online (AJOL)

    The problem of seasonal shortages of herbage production from natural pastures in the Ethiopian highlands was investigated. This was done by comparing the available biomass amounts on the pastures with biomass amounts required for livestock grazing and for protecting land slope from soil erosion within a given slope ...

  10. The evolution of institutions and rules governing communal grazing ...

    African Journals Online (AJOL)

    This paper traces the tradition and evolution of the institutions and rules governing communal grazing lands in Botswana. It shows how the problem of resource overuse arose partly from the dismantling and delegitimization of traditional resource management institutions that occurred during the colonial period, and was ...

  11. Research Note Identifying key grazing indicators to monitor trends in ...

    African Journals Online (AJOL)

    Research Note Identifying key grazing indicators to monitor trends in the veld condition of Lambert's Bay Strandveld, South Africa. ... from which a minimum number of species necessary to monitor trends in the condition of the veld were determined, making it user-friendly for land-users, extension officers and others. The key ...

  12. 1000 years of sustainable grazing in Nordic conditions?

    DEFF Research Database (Denmark)

    Brandt, Jesper

    landscapes at different spatial levels. Information on much of this sort of regulation has however been lost through modern times, tended to prefer modern (nature) scientific methods primarily developed as general (meaning not spatially contextual) recommendations for raising productivity. During the later...... years this modern tradition has also been preferred by investigations to find solutions for non-sustainable types of land use in grazing systems. However, much sustainability-relevant wisdom has been accumulated in historical grazing-systems that should be included in the repertoire of knowledge...

  13. Remote electronic monitoring and the landing obligation – some insights into fishers’ and fishery inspectors’ opinions

    DEFF Research Database (Denmark)

    Schreiber Plet-Hansen, Kristian; Qvist Eliasen, Søren; Mortensen, Lars O.

    2017-01-01

    , for such changes to be successful, it is vital to ensure stakeholders acceptance, and it is prudent to consider possible means to verify compliance with the new regulation. Remote Electronic Monitoring (REM) with Closed-Circuit Television (CCTV) has been tested in a variety of fisheries worldwide for different...... purposes and is currently considered as one possible tool to ensure compliance with a European ban on discards. This study focuses on Danish fishery inspectors and on fishers with REM experience, whose opinions are less well known. Their views on the landing obligation and on the use of REM were...... investigated using interviews and questionnaires, and contrasted to some fishers without REM experience. 80% of fishery inspectors and 58% of REM-experienced fishers expressed positive views on REM. 9 out of 10 interviewed fishers without REM experience were against REM. Participation in a REM trial has...

  14. Lucerne varieties for continuous grazing

    DEFF Research Database (Denmark)

    Søegaard, Karen

    2012-01-01

    severe grazing with heifers in two cutting/grazing managements. Two new varieties, Verbena and Camporegio, and an older variety Luzelle were established in 2009 in pure stands and in two different mixtures with perennial ryegrass (Lolium perenne). Camporegio had the lowest yield, the lowest competitive...... strength, the lowest plant density in spring, and the density was most reduced during grazing. The results could not confirm significant differences between the new and the older varieties. The results for Luzelle were generally between Verbena and Camporegio. The varieties did not differ in herbage...

  15. Phthalate esters contamination in soil and plants on agricultural land near an electronic waste recycling site.

    Science.gov (United States)

    Ma, Ting Ting; Christie, Peter; Luo, Yong Ming; Teng, Ying

    2013-08-01

    The accumulation of phthalic acid esters (PAEs) in soil and plants in agricultural land near an electronic waste recycling site in east China has become a great threat to the neighboring environmental quality and human health. Soil and plant samples collected from land under different utilization, including fallow plots, vegetable plots, plots with alfalfa (Medicago sativa L.) as green manure, fallow plots under long-term flooding and fallow plots under alternating wet and dry periods, together with plant samples from relative plots were analyzed for six PAE compounds nominated as prior pollutants by USEPA. In the determined samples, the concentrations of six target PAE pollutants ranged from 0.31-2.39 mg/kg in soil to 1.81-5.77 mg/kg in various plants (dry weight/DW), and their bioconcentration factors (BCFs) ranged from 5.8 to 17.9. Health risk assessments were conducted on target PAEs, known as typical environmental estrogen analogs, based on their accumulation in the edible parts of vegetables. Preliminary risk assessment to human health from soil and daily vegetable intake indicated that DEHP may present a high-exposure risk on all ages of the population in the area by soil ingestion or vegetable consumption. The potential damage that the target PAE compounds may pose to human health should be taken into account in further comprehensive risk assessments in e-waste recycling sites areas. Moreover, alfalfa removed substantial amounts of PAEs from the soil, and its use can be considered a good strategy for in situ remediation of PAEs.

  16. Revealing livestock effects on bunchgrass vegetation with Landsat ETM+ data across a grazing season

    Science.gov (United States)

    Jansen, Vincent S.

    Remote sensing provides monitoring solutions for more informed grazing management. To investigate the ability to detect the effects of cattle grazing on bunchgrass vegetation with Landsat Enhanced Thematic Mapper Plus (ETM+) data, we conducted a study on the Zumwalt Prairie in northeastern Oregon across a gradient of grazing intensities. Biophysical vegetation data was collected on vertical structure, biomass, and cover at three different time periods during the grazing season: June, August, and October 2012. To relate these measures to the remotely sensed Landsat ETM+ data, Pearson's correlations and multiple regression models were computed. Using the best models, predicted vegetation metrics were then mapped across the study area. Results indicated that models using common vegetation indices had the ability to discern different levels of grazing across the study area. Results can be distributed to land managers to help guide grassland conservation by improving monitoring of bunchgrass vegetation for sustainable livestock management.

  17. Grazing Incidence Optics Technology

    Science.gov (United States)

    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.

  18. Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

    Science.gov (United States)

    Arévalo, J. R.; de Nascimento, L.; Fernández-Lugo, S.; Mata, J.; Bermejo, L.

    2011-05-01

    Grazing management is probably one of the most extensive land uses, but its effects on plant communities have in many cases been revealed to be contradictory. Some authors have related these contradictions to the stochastic character of grazing systems. Because of that, it is necessary to implement specific analyses of grazing effects on each community, especially in natural protected areas, in order to provide the best information to managers. We studied the effects of grazing on the species composition of the main vegetation types where it takes place (grasslands, shrublands and pine forests) on the island of La Palma, Canary Islands. We used the point-quadrat intersect method to study the species composition of grazed and ungrazed areas, which also were characterized by their altitude, distance to farms, distance to settlements, year of sampling, herbaceous aboveground biomass and soil organic matter. The variables organic matter, productivity and species richness were not significantly affected by grazing. The species composition of the analyzed plant communities was affected more by variables such as altitude or distance to farms than by extensive grazing that has been traditionally carried out on the island of La Palma involving certain practices such as continuous monitoring of animals by goat keepers, medium stocking rates adjusted to the availability of natural pastures, supplementation during the dry season using local forage shrubs or mown pastures and rotating animals within grazing areas Although some studies have shown a negative effect of grazing on endangered plant species, these results cannot be freely extrapolated to the traditional grazing systems that exert a low pressure on plant communities (as has been found in this study). We consider extensive grazing as a viable way of ensuring sustainable management of the studied ecosystems.

  19. Graphite irradiated by swift heavy ions under grazing incidence

    CERN Document Server

    Liu, J; Müller, C; Neumann, R

    2002-01-01

    Highly oriented pyrolytic graphite is irradiated with various heavy projectiles (Ne, Ni, Zn, Xe and U) in the MeV to GeV energy range under different oblique angles of incidence. Using scanning tunneling microscopy, the impact zones are imaged as hillocks protruding from the surface. The diameter of surface-grazing tracks varies between 3 nm (Ne) and 6 nm (U), which is about twice as large as under normal beam incidence. Exclusively for U and Xe projectiles, grazing tracks exhibit long comet-like tails consisting of successive little bumps indicating that the damage along the ion path is discontinuous even for highest electronic stopping powers.

  20. Ecology of grazing lawns in Africa

    CSIR Research Space (South Africa)

    Hempson, GP

    2014-09-01

    Full Text Available 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...

  1. Axial grazing collisions with insulator surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gravielle, M.S. [Instituto de Astronomia y Fisica del Espacio (IAFE), Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, FCEN, Universidad de Buenos Aires (Argentina)]. E-mail: msilvia@iafe.uba.ar; Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio (IAFE), Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, FCEN, Universidad de Buenos Aires (Argentina)

    2007-05-15

    Electron capture and emission processes from insulator surfaces produced by grazing impact of fast ions are investigated under axial incidence conditions. For crystal surfaces we develop a model based on distorted wave methods, which allows us to express the coherent transition amplitude along the projectile path as a sum of atomic amplitudes, each one associated with a different lattice site. The method is applied to 100 keV protons colliding with LiF surfaces. For electron transitions from a given initial crystal state, the probabilities display strong interference effects as a function of the crystal orientation. But the interference patterns disappear when these partial probabilities are added to derive the total probability from the surface band.

  2. Axial grazing collisions with insulator surfaces

    International Nuclear Information System (INIS)

    Gravielle, M.S.; Miraglia, J.E.

    2007-01-01

    Electron capture and emission processes from insulator surfaces produced by grazing impact of fast ions are investigated under axial incidence conditions. For crystal surfaces we develop a model based on distorted wave methods, which allows us to express the coherent transition amplitude along the projectile path as a sum of atomic amplitudes, each one associated with a different lattice site. The method is applied to 100 keV protons colliding with LiF surfaces. For electron transitions from a given initial crystal state, the probabilities display strong interference effects as a function of the crystal orientation. But the interference patterns disappear when these partial probabilities are added to derive the total probability from the surface band

  3. Ionization by ion impact at grazing incidence on insulator surface

    CERN Document Server

    Martiarena, M L

    2003-01-01

    We have calculated the energy distribution of electrons produced by ionization of the ionic crystal electrons in grazing fast ion-insulator surface collision. The ionized electrons originate in the 2p F sup - orbital. We observe that the binary peak appears as a double change in the slope of the spectra, in the high energy region. The form of the peak is determined by the initial electron distribution and its position will be affected by the binding energy of the 2p F sup - electron in the crystal. This BEP in insulator surfaces will appear slightly shifted to the low energy side with respect the ion-atom one.

  4. 50 CFR 35.9 - Livestock grazing.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Livestock grazing. 35.9 Section 35.9... NATIONAL WILDLIFE REFUGE SYSTEM WILDERNESS PRESERVATION AND MANAGEMENT General Rules § 35.9 Livestock grazing. (a) The grazing of livestock, where established prior to the date of legislation which designates...

  5. Holistic Management: Misinformation on the Science of Grazed Ecosystems

    Directory of Open Access Journals (Sweden)

    John Carter

    2014-01-01

    Full Text Available Over 3 billion hectares of lands worldwide are grazed by livestock, with a majority suffering degradation in ecological condition. Losses in plant productivity, biodiversity of plant and animal communities, and carbon storage are occurring as a result of livestock grazing. Holistic management (HM has been proposed as a means of restoring degraded deserts and grasslands and reversing climate change. The fundamental approach of this system is based on frequently rotating livestock herds to mimic native ungulates reacting to predators in order to break up biological soil crusts and trample plants and soils to promote restoration. This review could find no peer-reviewed studies that show that this management approach is superior to conventional grazing systems in outcomes. Any claims of success due to HM are likely due to the management aspects of goal setting, monitoring, and adapting to meet goals, not the ecological principles embodied in HM. Ecologically, the application of HM principles of trampling and intensive foraging are as detrimental to plants, soils, water storage, and plant productivity as are conventional grazing systems. Contrary to claims made that HM will reverse climate change, the scientific evidence is that global greenhouse gas emissions are vastly larger than the capacity of worldwide grasslands and deserts to store the carbon emitted each year.

  6. Butterfly responses to prairie restoration through fire and grazing

    Science.gov (United States)

    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.

  7. Multisensor sampling of pelagic ecosystem variables in a coastal environment to estimate zooplankton grazing impact

    Science.gov (United States)

    Sutton, Tracey; Hopkins, Thomas; Remsen, Andrew; Burghart, Scott

    2001-01-01

    Sampling was conducted on the west Florida continental shelf ecosystem modeling site to estimate zooplankton grazing impact on primary production. Samples were collected with the high-resolution sampler, a towed array bearing electronic and optical sensors operating in tandem with a paired net/bottle verification system. A close biological-physical coupling was observed, with three main plankton communities: 1. a high-density inshore community dominated by larvaceans coincident with a salinity gradient; 2. a low-density offshore community dominated by small calanoid copepods coincident with the warm mixed layer; and 3. a high-density offshore community dominated by small poecilostomatoid and cyclopoid copepods and ostracods coincident with cooler, sub-pycnocline oceanic water. Both high-density communities were associated with relatively turbid water. Applying available grazing rates from the literature to our abundance data, grazing pressure mirrored the above bio-physical pattern, with the offshore sub-pycnocline community contributing ˜65% of grazing pressure despite representing only 19% of the total volume of the transect. This suggests that grazing pressure is highly localized, emphasizing the importance of high-resolution sampling to better understand plankton dynamics. A comparison of our grazing rate estimates with primary production estimates suggests that mesozooplankton do not control the fate of phytoplankton over much of the area studied (<5% grazing of daily primary production), but "hot spots" (˜25-50% grazing) do occur which may have an effect on floral composition.

  8. Spatial Distribution of Nitrogen on Grazed Karst Landscapes

    Directory of Open Access Journals (Sweden)

    Douglas G. Boyer

    2001-01-01

    Full Text Available The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian region. Karst areas comprise about 18% of the region’s land area. An estimated one-third of the region’s farms, cattle, and agricultural market value are located on karst terrain. Mean nitrate concentrations in several karst springs in southeastern West Virginia exhibit a strong linear relationship with the percentage of agriculture land cover. Development of best management practices for efficient nitrogen (N use and reduction of outflow of N to water from karst areas requires knowledge about N dynamics on those landscapes. Water extractable NO3-N and NH4-N were measured along transects at four soil depths in two grazed sinkholes and one wooded sinkhole. Distribution of soil NO3-N and NH4-N were related to frequency of animal presence and to topographic and hydrologic redistribution of soil and fecal matter in the grazed sinkholes. Karst pastures are characterized by under drainage and funneling of water and contaminants to the shallow aquifer. Control of NO3-N leaching from karst pasture may depend on management strategies that change livestock grazing behavior in sinkholes and reduce the opportunity for water and contaminants to quickly reach sinkhole drains.

  9. Are There Consistent Grazing Indicators in Drylands? Testing Plant Functional Types of Various Complexity in South Africa’s Grassland and Savanna Biomes

    Science.gov (United States)

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A.; Oomen, Roelof J.; du Preez, Chris C.; Ruppert, Jan C.; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants’ functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa’s grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be

  10. Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

    Directory of Open Access Journals (Sweden)

    Anja Linstädter

    Full Text Available Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa's grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs. Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses and two-trait PFTs (e.g. perennial grasses performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may

  11. Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

    Science.gov (United States)

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A; Oomen, Roelof J; du Preez, Chris C; Ruppert, Jan C; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa's grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be useful

  12. Projected use of grazed forages in the United States: 2000 to 2050: A technical document supporting the 2000 USDA Forest Service RPA Assessment

    Science.gov (United States)

    Larry W. van Tassell; E. Tom Bartlett; John E. Mitchell

    2001-01-01

    Scenario analysis techniques were used to combine projections from 35 grazed forage experts to estimate future forage demand scenarios and examine factors that are anticipated to impact the use of grazed forages in the South, North, and West Regions of the United States. The amount of land available for forage production is projected to decrease in all regions while...

  13. A Search for Electron Antineutrinos Associated with Gravitational-wave Events GW150914 and GW151226 Using KamLAND

    Science.gov (United States)

    Gando, A.; Gando, Y.; Hachiya, T.; Hayashi, A.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Karino, Y.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakamura, K.; Obara, S.; Oura, T.; Ozaki, H.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Takai, T.; Tamae, K.; Teraoka, Y.; Ueshima, K.; Watanabe, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Learned, J. G.; Maricic, J.; Sakai, M.; Winslow, L. A.; Krupczak, E.; Ouellet, J.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.; KamLAND Collaboration

    2016-10-01

    We present a search, using KamLAND, a kiloton-scale anti-neutrino detector, for low-energy anti-neutrino events that were coincident with the gravitational-wave (GW) events GW150914 and GW151226, and the candidate event LVT151012. We find no inverse beta-decay neutrino events within ±500 s of either GW signal. This non-detection is used to constrain the electron anti-neutrino fluence and the total integrated luminosity of the astrophysical sources.

  14. The grazing pattern of Muturu cattle under range system | Nweze ...

    African Journals Online (AJOL)

    Eighty Muturu cattle were grazed on rangeland, twice daily for two years to determine their grazing pattern. Twenty bulls and cows each between two to four years and forty calves between one to three months were used. The field grazing time (FGT), active grazing time (GT) and grazing travel time (GTT) were monitored.

  15. Grazing incidence diffraction : A review

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, B [LTPCM, ENSEEG. St. Martin d` Heres. (France)

    1996-09-01

    Different Grazing Incidence Diffraction (GID) methods for the analysis of thin films and multilayer structures are reviewed in three sections: the reflectivity is developed in the first one, which includes the non-specular diffuse scattering. The second one is devoted to the extremely asymmetric Bragg diffraction and the third one to the in-plane Bragg diffraction. Analytical formulations of the scattered intensities are developed for each geometry, in the framework of the kinetical analysis as well as the dynamical theory. Experimental examples are given to illustrate the quantitative possibility of the GID techniques.

  16. Equine Grazing in Managed Subalpine Wetlands: Effects on Arthropods and Plant Structure as a Function of Habitat

    Science.gov (United States)

    Holmquist, Jeffrey G.; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A.

    2013-12-01

    Grazing management necessarily emphasizes the most spatially extensive vegetation assemblages, but landscapes are mosaics, often with more mesic vegetation types embedded within a matrix of drier vegetation. Our primary objective was to contrast effects of equine grazing on both subalpine vegetation structure and associated arthropods in a drier reed grass ( Calamagrostis muiriana) dominated habitat versus a wetter, more productive sedge habitat ( Carex utriculata). A second objective was to compare reed grass and sedge as habitats for fauna, irrespective of grazing. All work was done in Sequoia National Park (CA, USA), where detailed, long-term records of stock management were available. We sampled paired grazed and control wet meadows that contained both habitats. There were moderate negative effects of grazing on vegetation, and effects were greater in sedge than in reed grass. Conversely, negative grazing effects on arthropods, albeit limited, were greater in the drier reed grass, possibly due to microhabitat differences. The differing effects on plants and animals as a function of habitat emphasize the importance of considering both flora and fauna, as well as multiple habitat types, when making management decisions. Sedge supported twice the overall arthropod abundance of reed grass as well as greater diversity; hemipteran and dipteran taxa were particularly abundant in sedge. Given the greater grazing effects on sedge vegetation, greater habitat provision for terrestrial arthropods, and value as aquatic arthropod habitat, the wetter sedge assemblage is worthy of additional consideration by managers when planning for grazing and other aspects of land usage.

  17. Simulating runoff from small grazed pasture watersheds located at North Appalachian Experimental Watershed in Ohio

    Science.gov (United States)

    Runoff from grazing pasture lands can impact water quality in receiving streams if not well managed. Management consists of conservation practices to reduce runoff and pollutants transport. Simulation models have been effectively used to design and implement these conservation practices. The Agricul...

  18. Knowledge and tools to enhance resilience of beef grazing systems for sustainable animal protein production.

    Science.gov (United States)

    Steiner, Jean L; Engle, David M; Xiao, Xiangming; Saleh, Ali; Tomlinson, Peter; Rice, Charles W; Cole, N Andy; Coleman, Samuel W; Osei, Edward; Basara, Jeffrey; Middendorf, Gerad; Gowda, Prasanna; Todd, Richard; Moffet, Corey; Anandhi, Aavudai; Starks, Patrick J; Ocshner, Tyson; Reuter, Ryan; Devlin, Daniel

    2014-11-01

    Ruminant livestock provides meat and dairy products that sustain health and livelihood for much of the world's population. Grazing lands that support ruminant livestock provide numerous ecosystem services, including provision of food, water, and genetic resources; climate and water regulation; support of soil formation; nutrient cycling; and cultural services. In the U.S. southern Great Plains, beef production on pastures, rangelands, and hay is a major economic activity. The region's climate is characterized by extremes of heat and cold and extremes of drought and flooding. Grazing lands occupy a large portion of the region's land, significantly affecting carbon, nitrogen, and water budgets. To understand vulnerabilities and enhance resilience of beef production, a multi-institutional Coordinated Agricultural Project (CAP), the "grazing CAP," was established. Integrative research and extension spanning biophysical, socioeconomic, and agricultural disciplines address management effects on productivity and environmental footprints of production systems. Knowledge and tools being developed will allow farmers and ranchers to evaluate risks and increase resilience to dynamic conditions. The knowledge and tools developed will also have relevance to grazing lands in semiarid and subhumid regions of the world. © 2014 New York Academy of Sciences.

  19. 36 CFR 292.22 - Land category assignments.

    Science.gov (United States)

    2010-07-01

    ... land. (iv) Commercial land. (2) Not later than August 12, 1994, a map or maps displaying the privately... availability of this map or maps in the local newspapers of record. (b) Changes in land category assignment.../grazing land so long as the intended use or development is consistent with the standards in § 292.23 and...

  20. Contrasting Effects of Cattle Grazing Intensity on Upland-Nesting Duck Production at Nest and Field Scales in the Aspen Parkland, Canada

    Directory of Open Access Journals (Sweden)

    Jeffrey M. Warren

    2008-12-01

    Full Text Available The Aspen Parkland of Canada is one of the most important breeding areas for temperate nesting ducks in North America. The region is dominated by agricultural land use, with approximately 9.3 million ha in pasture land for cattle grazing. However, the effects of using land for cattle grazing on upland-nesting duck production are poorly understood. The current study was undertaken during 2001 and 2002 to investigate how nest density and nesting success of upland-nesting ducks varied with respect to the intensity of cattle grazing in the Aspen Parkland. We predicted that the removal and trampling of vegetation through cattle grazing would reduce duck nest density. Both positive and negative responses of duck nesting success to grazing have been reported in previous studies, leading us to test competing hypotheses that nesting success would (1 decline linearly with grazing intensity or (2 peak at moderate levels of grazing. Nearly 3300 ha of upland cover were searched during the study. Despite extensive and severe drought, nest searches located 302 duck nests. As predicted, nest density was higher in fields with lower grazing intensity and higher pasture health scores. A lightly grazed field with a pasture score of 85 out of a possible 100 was predicted to have 16.1 nests/100 ha (95% CI = 11.7-22.1, more than five times the predicted nest density of a heavily grazed field with a pasture score of 58 (3.3 nests/100 ha, 95% CI = 2.2-4.5. Nesting success was positively related to nest-site vegetation density across most levels of grazing intensity studied, supporting our hypothesis that reductions in vegetation caused by grazing would negatively affect nesting success. However, nesting success increased with grazing intensity at the field scale. For example, nesting success for a well-concealed nest in a lightly grazed field was 11.6% (95% CI = 3.6-25.0%, whereas nesting success for a nest with the same level of nest-site vegetation in a heavily grazed

  1. Herbage intake by grazing dairy cows

    NARCIS (Netherlands)

    Meijs, J.A.C.

    1981-01-01

    An extensive review of the literature is given of
    - nine possible methods for estimating herbage intake by grazing ruminants, with special attention to the sward-cutting and indirect animal methods
    - the factors determining the herbage intake by grazing ruminants.

    The

  2. Lande gJ factors for even-parity electronic levels in the holmium atom

    Science.gov (United States)

    Stefanska, D.; Werbowy, S.; Krzykowski, A.; Furmann, B.

    2018-05-01

    In this work the hyperfine structure of the Zeeman splitting for 18 even-parity levels in the holmium atom was investigated. The experimental method applied was laser induced fluorescence in a hollow cathode discharge lamp. 20 spectral lines were investigated involving odd-parity levels from the ground multiplet, for which Lande gJ factors are known with high precision, as the lower levels; this greatly facilitated the evaluation of gJ factors for the upper levels. The gJ values for the even-parity levels considered are reported for the first time. They proved to compare fairly well with the values obtained recently in a semi-empirical analysis for the even-parity level system of Ho I.

  3. Study of electronic excitation and diffraction effects as well as growth, structure, and magnetic properties of ultrathin 3d metal films on Cu(001) by means of grazing-incidence ion scattering; Untersuchung elektronischer Anregungs- und Beugungseffekte sowie Wachstum, Struktur und magnetischer Eigenschaften ultraduenner 3d-Metallfilme auf Cu(001) mittels streifender Ionenstreuung

    Energy Technology Data Exchange (ETDEWEB)

    Bernhard, T.

    2006-11-23

    H{sup +} and He{sup +} ions with an energy of 25 keV are scattered under a grazing angle of incidence from a clean and flat Cu(001) surface. For specific azimuthal orientations of the crystal surface with respect to low index directions in the surface plane we observe the ion induced emission of electrons with a conventional LEED (low energy electron diffraction) setup. By operating the instrument in an energy dispersive mode we find intensity distributions of emitted electrons which can unequivocally be ascribed to diffraction effects at the target surface. From this ion induced LEED-reflexes (IILEED) we get important information about the electron excitation- and emission effects during the scattering process. In the second part of this work we investigate the correlation between thin-film growth (Co,Fe,Mn on Cu(001)) and electron emission in the regime of grazing ion scattering. The ''rough'' surface of uncompleted layers increase the probability of binary collisions of incident ions with individual atoms at the surface. The energy spectras and the number distribution of emitted electrons are substantially influenced by these ''violent'' collisions and allow us to monitor growth of thin films via simple measurements of target current or from energy spectra of emitted electrons. The method provides excellent signals and is also applicable in the regime of poor layer growth. By making use of ion beam triangulation (IBT), direct information on the atomic structure of thin films and substrate surfaces is obtained. We discuss in the third part of this work a new variant of this method based on the detection of the number of emitted electrons. The data are analyzed via computer simulations using classical mechanics which provides a quantitative analysis with respect to projectile trajectories. This new detection scheme allows the determination of the in-plane structure of reconstructed thin films and surfaces with high precision

  4. Governing Grazing and Mobility in the Samburu Lowlands, Kenya

    Directory of Open Access Journals (Sweden)

    Annemiek Pas

    2018-03-01

    Full Text Available Pastoral mobility is seen as the most effective strategy to make use of constantly shifting resources. However, mobile pastoralism as a highly-valued strategy to manage grazing areas and exploit resource variability is becoming more complex, due to recurrent droughts, loss of forage, government-led settlement schemes, and enclosure of land for community conservation, among other reasons. Yet knowledge of how Samburu pastoralists perceive these changes, and govern and innovate in their mobility patterns and resource use, has received limited attention. This paper seeks to understand how Samburu pastoralists in the drylands of northern Kenya use and govern natural resources, how livestock grazing and mobility is planned for, and how boundaries and territory are constructed and performed both within and beyond the context of (nongovernmental projects. Fieldwork for this paper was conducted in Sesia, Samburu East, and consisted of interviews, focus group discussions, and participatory observation. Findings show that livestock mobility involves longer periods and more complex distances due to a shrinking resource base and new rules of access. Although access was previously generated based on the value of reciprocity, the creation of new forms of resource management results in conditional processes of inclusion and exclusion. Policy and project implementation has historically been driven by the imperative to secure land tenure and improve pasture in bounded areas. Opportunities to support institutions that promote mobility have been given insufficient attention.

  5. Sustainability, arid grasslands and grazing: New applications for technology

    Energy Technology Data Exchange (ETDEWEB)

    Pregenzer, A.L.; Parmenter, R.; Passell, H.D.; Budge, T.; Vande Caste, J.

    1999-12-08

    The study of ecology is taking on increasing global importance as the value of well-functioning ecosystems to human well-being becomes better understood. However, the use of technological systems for the study of ecology lags behind the use of technologies in the study of other disciplines important to human well-being, such as medicine, chemistry and physics. The authors outline four different kinds of large-scale data needs required by land managers for the development of sustainable land use strategies, and which can be obtained with current or future technological systems. They then outline a hypothetical resource management scenario in which data on all those needs are collected using remote and in situ technologies, transmitted to a central location, analyzed, and then disseminated for regional use in maintaining sustainable grazing systems. They conclude by highlighting various data-collection systems and data-sharing networks already in operation.

  6. Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie.

    Science.gov (United States)

    Manning, George C; Baer, Sara G; Blair, John M

    2017-12-01

    Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies (P soil bulk density were also higher in grazed prairie soil over all fire frequencies (P soil N were positively correlated with FQI (P soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

  7. Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie

    Science.gov (United States)

    Manning, George C.; Baer, Sara G.; Blair, John M.

    2017-12-01

    Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies ( P total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies ( P total organic C, and total soil N were positively correlated with FQI ( P quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

  8. 36 CFR 293.7 - Grazing of livestock.

    Science.gov (United States)

    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 the...

  9. Productivity of grasslands under continuous and rotational grazing

    NARCIS (Netherlands)

    Lantinga, E.A.

    1985-01-01

    In the Netherlands, rotational grazing, with grazing periods of 2 to 5 days, is the most common grazing system at present. In contrast with other countries of North-western Europe, the continuous grazing system is used here only to a limited extent. However, the results of numerous

  10. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Directory of Open Access Journals (Sweden)

    Agustina di Virgilio

    2016-06-01

    Full Text Available Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock grazing on three different paddocks (with sizes from 80 to 1000 Ha during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets, age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females used more intensively the most preferred areas and low-ranked (i.e., yearlings used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour. Discussion. Although homogenization and segregation of

  11. Towards evenly distributed grazing patterns: including social context in sheep management strategies.

    Science.gov (United States)

    di Virgilio, Agustina; Morales, Juan Manuel

    2016-01-01

    Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals' foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals' space use patterns, our aim was to explore the potential effects of including animals' social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by classes

  12. Biological soil crusts across disturbance–recovery scenarios: effect of grazing regime on community dynamics.

    Science.gov (United States)

    Concostrina-Zubiri, L; Huber-Sannwald, E; Martínez, I; Flores Flores, J L; Reyes-Agüero, J A; Escude, A; Belnap, J

    Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

  13. Biological soil crusts across disturbance-recovery scenarios: effect of grazing regime on community dynamics

    Science.gov (United States)

    Concostrina-Zubiri, L.; Huber-Sannwald, E.; Martínez, I.; Flores Flores, J. L.; Reyes-Agüero, J. A.; Escudero, A.; Belnap, Jayne

    2014-01-01

    Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

  14. Emergy analysis of cropping-grazing system in Inner Mongolia Autonomous Region, China

    International Nuclear Information System (INIS)

    Zhang, L.X.; Yang, Z.F.; Chen, G.Q.

    2007-01-01

    An ecological energetic evaluation is presented in this paper as a complement to economic account for the cropping-grazing system in the Inner Mongolia Autonomous Region in China in the year 2000. Based on Odum's well-known concept of emergy in terms of embodied solar energy as a unified measure for environmental resources, human or animal labors and industrial products, a systems diagram is developed for the crop and livestock productions with arms and sub-arms for free renewable natural resource input, purchased economic investment, yields of and interactive fluxes between the cropping and grazing sub-industries. In addition to conventional systems indices of the emergy yield ratio (EYR), emergy investment ratio (EIR), environmental load ratio (ELR) and environmental sustainability index (ESI) introduced for congregated systems ecological assessment with essential implication for sustainability, new indicators of soil emergy cost (SEC), self-support intensity (SSI) and self-support orientation (SSO) are defined to characterize the desertification and internal recycling associated with the special agricultural system. Extensive emergy accounting is made for the cropping-grazing system as a whole as well as for the cropping and grazing subsystems. The overall cropping-grazing system is shown with outstanding production competence compared with agricultural systems in some other provinces and the national average in China, though confronted with severe desertification associated with soil loss. The production of crops has higher emergy density and yield rate per unit area as well as higher rate of soil loss than grazing system. The soil emergy cost defined as the soil loss emergy divided by the yield emergy is estimated to be of the same value for both of the subsystems, but the grazing activity is with less extraction intensity, leaving rangeland to rest and rehabilitate. Suggestions with regard to the local sustainability and national ecological security in

  15. Grazing management that regenerates ecosystem function and ...

    African Journals Online (AJOL)

    Grazing management that regenerates ecosystem function and grazingland ... in ecosystem improvement, productivity, soil carbon and fertility, water-holding ... for sufficient time to produce resource improvement, sound animal production, and ...

  16. Runoff changes have a land cover specific effect on the seasonal fluxes of terminal electron acceptors in the boreal catchments.

    Science.gov (United States)

    Mattsson, Tuija; Lehtoranta, Jouni; Ekholm, Petri; Palviainen, Marjo; Kortelainen, Pirkko

    2017-12-01

    Climate change influences the volume and seasonal distribution of runoff in the northern regions. Here, we study how the seasonal variation in the runoff affects the concentrations and export of terminal electron acceptors (i.e. TEAs: NO 3 , Mn, Fe and SO 4 ) in different boreal land-cover classes. Also, we make a prediction how the anticipated climate change induced increase in runoff will alter the export of TEAs in boreal catchments. Our results show that there is a strong positive relationship between runoff and the concentration of NO 3 -N, Mn and Fe in agricultural catchments. In peaty catchments, the relationship is poorer and the concentrations of TEAs tend to decrease with increasing runoff. In forested catchments, the correlation between runoff and TEA concentrations was weak. In most catchments, the concentrations of SO 4 decrease with an increase in runoff regardless of the land cover or season. The wet years export much higher amounts of TEAs than the dry years. In southern agricultural catchments, the wet years increased the TEA export for both spring (January-May) and autumn (September-December) periods, while in the peaty and forested catchments in eastern and northern Finland the export only increased in the autumn. Our predictions for the year 2099 indicate that the export of TEAs will increase especially from agricultural but also from forested catchments. Additionally, the predictions show an increase in the export of Fe and SO 4 for all the catchments for the autumn. Thus, the climate induced change in the runoff regime is likely to alter the exported amount of TEAs and the timing of the export downstream. The changes in the amounts and timing in the export of TEAs have a potential to modify the mineralization pathways in the receiving water bodies, with feedbacks in the cycling of C, nutrients and metals in aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The magnetic domain structures of Fe thin films on rectangular land-and-groove substrates studied by spin-polarized secondary electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, S. [Photodynamics Research Center, RIKEN, Aoba-ku, Sendai 980-0845 (Japan)]. E-mail: uedas@postman.riken.go.jp; Iwasaki, Y. [Photodynamics Research Center, RIKEN, Aoba-ku, Sendai 980-0845 (Japan); Micro Systems Network Company, Sony Corporation, Tagajo, Miyagi 985-0842 (Japan); Ushioda, S. [Photodynamics Research Center, RIKEN, Aoba-ku, Sendai 980-0845 (Japan); Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai 980-8577 (Japan)

    2004-10-01

    The magnetic domain structures of Fe thin films on rectangular land-and-groove structures have been studied by spin-polarized secondary electron microscopy (SP-SEM) under an applied dc field. The coercive force on the land area was found to be higher than that on the groove area in the magnetization reversal due to the difference in surface roughness between land and groove areas. The magnetic domain structure and domain wall pinning behavior during the reversal process depended on the direction of the magnetic field relative to the rectangles. These results show that the anisotropy induced by film geometry also contributes to the magnetization reversal process of thin magnetic films on land{sub a}nd{sub g}roove substrates.

  18. Regional livestock grazing, human demography and fire incidence in the Portuguese landscape

    Directory of Open Access Journals (Sweden)

    Filipa Torres-Manso

    2014-04-01

    Full Text Available Aim of study:Wildfire incidence in Portugal is high in comparison with other Mediterranean Europe countries. Wildfire problems have been worsened by complex interactions between land use, livestock grazing and human population during the 20th century. In this study we try to understand these interactions and relationships.Area of study: Portugal country. Material and Methods: For the mainland Portuguese territory we present a statistical temporal analysis (1930-2001 based on the densities of livestock grazing and human inhabitants at the smallest administrative unit level, the parish. We compare these data with fire incidence descriptors (average area burned and average fire density between 1990 and 2007. Research highlights: We have identified clusters of parishes sharing common trends in the evolution of livestock and human inhabitant densities. A cause-effect relationship was not detected between livestock grazing density and fire incidence. However, the results point out clusters of parishes where conflicts between forest, fire and livestock grazing are important in the North, Centre and South regions of Portugal.Key Words: Livestock grazing; inhabitants; forest; fire; vegetation.

  19. Grazing function g and collimation angular acceptance

    Directory of Open Access Journals (Sweden)

    Stephen G. Peggs

    2009-11-01

    Full Text Available The grazing function g is introduced—a synchrobetatron optical quantity that is analogous (and closely connected to the Twiss and dispersion functions β, α, η, and η^{′}. 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 β or η 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.

  20. Grazing behavior and intake of goats rotationally grazing Tanzania-grass pasture with different post-grazing residues

    Directory of Open Access Journals (Sweden)

    Marcia H.M.R. Fernandes

    2016-05-01

    Full Text Available This study aimed to evaluate intake and ingestive behavior of goats rotationally grazing Tanzania (Panicum maximum cv. Tanzânia 1 pastures with 2 levels of post-grazing residue. The experimental area consisted of 1.2 ha of Tanzania pasture divided into 12 paddocks (24 areas, managed under 2 post-grazing residues: low green (leaf + stem herbage mass (GHM post-grazing (LR, approximately 1,500 kg/ha GHM; and high GHM post-grazing (HR, approximately 3,000 kg/ha GHM. Each paddock was grazed for 3 consecutive days (D1, D2, D3 followed by 33 days rest and evaluated from October 2005 to April 2006. Animal behavior (grazing time, bite rate and bite size/weight was evaluated on each grazing day. While goats spent more time grazing on LR than HR (P=0.02, bite rate did not differ between treatments or among days (P=0.31 and averaged 26.5 bites/min. In contrast, bite weight was greater in HR (0.15 g/bite than in LR (0.12 g/bite, and decreased from D1 to D3 (P<0.001. Absolute dry matter intake of goats was greater in the HR (2.19 kg/d than the LR (1.89 kg/d treatment; however, differences were not significant (P>0.05 when intake was determined on a body weight or metabolic weight basis. Our findings are consistent with the general assumption that bite weight is a trade-off between quantity and quality of the herbage mass and is the main determinant of animal performance. More studies are needed to determine animal performance on the various treatments and to determine management strategies to provide a desirable balance between animal weight gain and pasture stability.Keywords: Animal behavior, foraging, grazing systems, Megathyrsus maximus, plant - animal relations.DOI: 10.17138/TGFT(491-100

  1. Mineral supplementation for grazing ruminants

    International Nuclear Information System (INIS)

    McDowell, L.R.; Conrad, J.H.; Ellis, G.L.

    1986-01-01

    Grazing ruminants to which concentrate feeds cannot be economically fed must rely on self-feeding of mineral supplements. A number of factors affect mineral consumption of free-choice mixtures. Livestock exhibit little nutritional wisdom and will select palatable mixtures in preference to mixtures designed to meet their requirements. Palatability and appetite stimulators are often used to achieve a more uniform herd-wide consumption. It is best to formulate free-choice mixtures on the basis of analyses or other available data. However, when no information on mineral status is known, a free-choice complete mineral supplement is warranted. A 'complete' mineral mixture usually includes salt, a low fluoride P source, Ca, Co, Cu, I, Mn and Zn. Selenium, Mg, K, S, Fe or additional elements can be incorporated into a mineral supplement as new information suggests a need. The detriment to ruminant production caused by providing Ca, Se and Cu in excess can be greater than any benefit derived by providing a mineral supplement. In regions where high forage Mo predominates, three to five times the Cu content in mineral mixtures is needed to counteract Mo toxicity. Supplemental minerals are most critical during the wet season, when cattle are gaining weight rapidly and energy and protein supplies are adequate. Economic return on mineral supplementation is high. (author)

  2. Nest survival of American Coots relative to grazing, burning, and water depths

    Science.gov (United States)

    Austin, Jane E.; Buhl, Deborah A.

    2011-01-01

    Water and emergent vegetation are key features influencing nest site selection and success for many marsh-nesting waterbirds. Wetland management practices such as grazing, burning, and water-level manipulations directly affect these features and can influence nest survival. We used model selection and before-after-control-impact approaches to evaluate the effects of water depth and four common land-management practices or treatments, i.e., summer grazing, fall grazing, fall burning, and idle (no active treatment) on nest survival of American coots (Fulica americana) nesting at Grays Lake, a large montane wetland in southeast Idaho. The best model included the variables year × treatment, and quadratic functions of date, water depth, and nest age; height of vegetation at the nest did not improve the best model. However, results from the before-after-control-impact analysis indicate that management practices affected nest success via vegetation and involved interactions of hydrology, residual vegetation, and habitat composition. Nest success in idled fields changed little between pre- and post-treatment periods, whereas nest success declined in fields that were grazed or burned, with the most dramatic declines the year following treatments. The importance of water depth may be amplified in this wetland system because of rapid water-level withdrawal during the nesting season. Water and land-use values for area ranchers, management for nesting waterbirds, and long-term wetland function are important considerations in management of water levels and vegetation.

  3. Relationships among rotational and conventional grazing systems, stream channels, and macroinvertebrates

    Science.gov (United States)

    Raymond, K.L.; Vondracek, B.

    2011-01-01

    Cattle grazing in riparian areas can reduce water quality, alter stream channel characteristics, and alter fish and macroinvertebrate assemblage structure. The U.S. Department of Agriculture, Natural Resources Conservation Services has recommended Rotational Grazing (RG) as an alternative management method on livestock and dairy operations to protect riparian areas and water quality. We evaluated 13 stream channel characteristics, benthic macroinvertebrate larvae (BML), and chironomid pupal exuviae (CPE) from 18 sites in the Upper Midwest of the United States in relation to RG and conventional grazing (CG). A Biotic Composite Score comprised of several macroinvertebrate metrics was developed for both the BML assemblage and the CPE assemblage. Multi-Response Permutation Procedures (MRPP) indicated a significant difference in stream channel characteristics between RG and CG. Nonmetric Multidimensional Scaling indicated that RG sites were associated with more stable stream banks, higher quality aquatic habitat, lower soil compaction, and larger particles in the streambed. However, neither MRPP nor Mann-Whitney U tests demonstrated a difference in Biotic Composite Scores for BML or CPE along RG and CG sites. The BML and CPE metrics were significantly correlated, indicating that they were likely responding to similar variables among the study sites. Although stream channel characteristics appeared to respond to grazing management, BML and CPE may have responded to land use throughout the watershed, as well as local land use. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  4. Nest Survival of American Coots Relative to Grazing, Burning, and Water Depths

    Directory of Open Access Journals (Sweden)

    Jane E. Austin

    2011-12-01

    Full Text Available Water and emergent vegetation are key features influencing nest site selection and success for many marsh-nesting waterbirds. Wetland management practices such as grazing, burning, and water-level manipulations directly affect these features and can influence nest survival. We used model selection and before-after-control-impact approaches to evaluate the effects of water depth and four common land-management practices or treatments, i.e., summer grazing, fall grazing, fall burning, and idle (no active treatment on nest survival of American coots (Fulica americana nesting at Grays Lake, a large montane wetland in southeast Idaho. The best model included the variables year × treatment, and quadratic functions of date, water depth, and nest age; height of vegetation at the nest did not improve the best model. However, results from the before-after-control-impact analysis indicate that management practices affected nest success via vegetation and involved interactions of hydrology, residual vegetation, and habitat composition. Nest success in idled fields changed little between pre- and post-treatment periods, whereas nest success declined in fields that were grazed or burned, with the most dramatic declines the year following treatments. The importance of water depth may be amplified in this wetland system because of rapid water-level withdrawal during the nesting season. Water and land-use values for area ranchers, management for nesting waterbirds, and long-term wetland function are important considerations in management of water levels and vegetation.

  5. The grazing capacity of sweetveld: 2. A model to estimate grazing ...

    African Journals Online (AJOL)

    The relations between grazing capacity and three independent variables were investigated in the False Thornveld of the Eastern Cape. The variables were veld condition, rainfall and density of woody species. These relations were used to develop a preliminary model to assess grazing capacity in the veld type. Despite its ...

  6. Land use/Land Cover Changes and Causes of Deforestation in the ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2015-09-04

    Sep 4, 2015 ... The semi – Automatic Classification Plugin Version 4.9.1 of the QGIS was used for the land use/land ... logging, grazing, urbanisation, road construction and ... environment. The most dramatic impact is loss of habitat for millions of species with serious implication for eco – tourism and loss of biodiversity.

  7. Solid-state 13C NMR experiments reveal effects of aggregate size on the chemical composition of particulate organic matter in grazed steppe soils

    Science.gov (United States)

    Steffens, M.; Kölbl, A.; Kögel-Knabner, I.

    2009-04-01

    Grazing is one of the most important factors that may reduce soil organic matter (SOM) stocks and subsequently deteriorate aggregate stability in grassland topsoils. Land use management and grazing reduction are assumed to increase the input of OM, improve the soil aggregation and change species composition of vegetation (changes depth of OM input). Many studies have evaluated the impact of grazing cessation on SOM quantity. But until today little is known about the impact of grazing cessation on the chemical quality of SOM in density fractions, aggregate size classes and different horizons. The central aim of this study was to analyse the quality of SOM fractions in differently sized aggregates and horizons as affected by increased inputs of organic matter due to grazing exclusion. We applied a combined aggregate size, density and particle size fractionation procedure to sandy steppe topsoils with different organic matter inputs due to different grazing intensities (continuously grazed = Cg, winter grazing = Wg, ungrazed since 1999 = Ug99, ungrazed since 1979 = Ug79). Three different particulate organic matter (POM; free POM, in aggregate occluded POM and small in aggregate occluded POM) and seven mineral-associated organic matter fractions were separated for each of three aggregate size classes (coarse = 2000-6300 m, medium = 630-2000 m and fine =

  8. Cold season soil respiration in response to grazing and warming in the High Arctic Svalbard

    DEFF Research Database (Denmark)

    Strebel, Ditte; Elberling, Bo; Morgner, Elke

    2010-01-01

    of Arctic Goose Habitat: Impacts of Land Use, Conservation and Elevated Temperatures). New measurements of soil CO2 effluxes, temperatures and water contents were regularly made from July to November 2007. SOC stocks were quantified, and the reactivity and composition measured by basal soil respiration (BSR...... be concluded that two years after a goose grazing experiment, SOC cycling was less than the natural variation within contrasting vegetation types....

  9. Fungi regulate response of N2O production to warming and grazing in a Tibetan grassland

    Science.gov (United States)

    Zhong, Lei; Wang, Shiping; Xu, Xingliang; Wang, Yanfen; Rui, Yichao; Zhou, Xiaoqi; Shen, Qinhua; Wang, Jinzhi; Jiang, Lili; Luo, Caiyun; Gu, Tianbao; Ma, Wenchao; Chen, Guanyi

    2018-03-01

    Lack of understanding of the effects of warming and winter grazing on soil fungal contribution to nitrous oxide (N2O) production has limited our ability to predict N2O fluxes under changes in climate and land use management, because soil fungi play an important role in driving terrestrial N cycling. Here, we examined the effects of 10 years' warming and winter grazing on soil N2O emissions potential in an alpine meadow. Our results showed that soil bacteria and fungi contributed 46 % and 54 % to nitrification, and 37 % and 63 % to denitrification, respectively. Neither warming nor winter grazing affected the activity of enzymes responsible for overall nitrification and denitrification. However, warming significantly increased the enzyme activity of bacterial nitrification and denitrification to 53 % and 55 %, respectively. Warming significantly decreased enzyme activity of fungal nitrification and denitrification to 47 % and 45 %, respectively, while winter grazing had no such effect. We conclude that soil fungi could be the main source for N2O production potential in the Tibetan alpine grasslands. Warming and winter grazing may not affect the potential for soil N2O production potential, but climate warming can alter biotic pathways responsible for N2O production. These findings indicate that characterizing how fungal nitrification/denitrification contributes to N2O production, as well as how it responds to environmental and land use changes, can advance our understanding of N cycling. Therefore, our results provide some new insights about ecological controls on N2O production and lead to refine greenhouse gas flux models.

  10. The effects of burning and grazing on soil carbon dynamics in managed Peruvian tropical montane grasslands

    Science.gov (United States)

    Oliver, Viktoria; Oliveras, Imma; Kala, Jose; Lever, Rebecca; Arn Teh, Yit

    2017-12-01

    Montane tropical soils are a large carbon (C) reservoir, acting as both a source and a sink of CO2. Enhanced CO2 emissions originate, in large part, from the decomposition and losses of soil organic matter (SOM) following anthropogenic disturbances. Therefore, quantitative knowledge of the stabilization and decomposition of SOM is necessary in order to understand, assess and predict the impact of land management in the tropics. In particular, labile SOM is an early and sensitive indicator of how SOM responds to changes in land use and management practices, which could have major implications for long-term carbon storage and rising atmospheric CO2 concentrations. The aim of this study was to investigate the impacts of grazing and fire history on soil C dynamics in the Peruvian montane grasslands, an understudied ecosystem, which covers approximately a quarter of the land area in Peru. A density fractionation method was used to quantify the labile and stable organic matter pools, along with soil CO2 flux and decomposition measurements. Grazing and burning together significantly increased soil CO2 fluxes and decomposition rates and reduced temperature as a driver. Although there was no significant effect of land use on total soil C stocks, the combination of burning and grazing decreased the proportion of C in the free light fraction (LF), especially at the lower depths (10-20 and 20-30 cm). In the control soils, 20 % of the material recovered was in the free LF, which contained 30 % of the soil C content. In comparison, the burnt-grazed soil had the smallest recovery of the free LF (10 %) and a significantly lower C content (14 %). The burnt soils had a much higher proportion of C in the occluded LF (12 %) compared to the not-burnt soils (7 %) and there was no significant difference among the treatments in the heavy fraction (F) ( ˜ 70 %). The synergistic effect of burning and grazing caused changes to the soil C dynamics. CO2 fluxes were increased and the dominant

  11. Grazing-incident PIXE Analysis Technology

    International Nuclear Information System (INIS)

    Li Hongri; Wang Guangpu; Liang Kun; Yang Ru; Han Dejun

    2009-01-01

    In the article, the grazing incidence technology is first applied to the PIXE (proton induced X-ray emission) analysis. Three pieces of samples were investigated, including the contaminated aluminium substrate, the SIMOX (separated by oxygen implantation) SOI (Silicon on Insulator) sample and the silicon wafer implanted with Fe + . The results reveal that the grazing-incident proton can improve the sensitivity of PIXE in trace analysis, especially for samples contaminated on surface. With the penetration depth of the proton bean decreased, the ratio of the peak area to the detection limit raised observably and the sensitivity near the sample surface increased. (authors)

  12. Effect of grazing frequency and intensity on Lolium perenne L ...

    African Journals Online (AJOL)

    ) system. Low frequency, low intensity grazing produced lower CDMD and herbage N levels than higher grazing frequencies and intensities. These differences were, however, generally small. Overall, levels of herbage digestibility (estimated ...

  13. Effect of land use types in Miesa Watershed on soil quality and ...

    African Journals Online (AJOL)

    This study was undertaken to investigate the effects of land use types on physicochemical and biological properties of soil and hence on soil fertility and soil productivity. In order to investigate soil fertility status, soil samples collected from different land use types (cultivated land, grazing land and natural forest) from the ...

  14. Grazing intensity affects the environmental impact of dairy systems.

    Science.gov (United States)

    Aguirre-Villegas, H A; Passos-Fonseca, T H; Reinemann, D J; Larson, R

    2017-08-01

    Dairy products are major components of the human diet but are also important contributors to global environmental impacts. This study evaluated greenhouse gas (GHG) emissions, net energy intensity (NEI), and land use of confined dairy systems with increasing levels of pasture in the diet. A Wisconsin farm was modeled to represent practices adopted by dairy operations in a humid continental climate typical in the Great Lakes region and other climates that have large differences in seasonal temperatures. Five grazing scenarios (all of which contained some portion of confinement) were modeled based on different concentrations of dry matter intake from pasture and feed supplementation from corn grain, corn silage, and soybean meal. Scenarios that incorporate grazing consisted of 5 mo of pasture feeding from May to September and 7 mo of confined feeding from October to April. Environmental impacts were compared within the 5 scenarios that incorporate grazing and across 2 entirely confined scenarios with and without on-farm electricity production through anaerobic digestion (AD). To conduct a fair comparison, all scenarios were evaluated based on the same total amount of milk produced per day where resource inputs were adjusted according to the characteristics of each scenario. A cradle-to-farm gate life cycle assessment evaluated the environmental burdens that were partitioned by allocation between milk and meat and by system expansion when biogas-based electricity was produced. Overall, results for all scenarios were comparable. Enteric methane was the greatest contributor to GHG emissions, and the production of crops was the most energy-intense process. For the confined scenario without AD, GHG emissions were 0.87 kg of CO 2 equivalents, NEI was 1.59 MJ, and land use was 1.59 m 2 /kg of fat- and protein-corrected milk (FPCM). Anaerobic digestion significantly reduced emissions to 0.28 kg of CO 2 equivalents/kg of FPCM and reduced NEI to -1.26 MJ/kg of FPCM, indicating

  15. Progress Report: Stratton Ecological Research Site - An Experimental Approach to Assess Effects of Various Grazing Treatments on Vegetation and Wildlife Communities Across Managed Burns and Habitat Controls

    Science.gov (United States)

    Erickson, Heidi J.; Aldridge, Cameron L.; Hobbs, N. Thompson

    2009-01-01

    Understanding how management practices affect wildlife is fundamental to wise decisions for conservation of public lands. Prescribed fire and grazing timing are two management tools frequently used within publicly owned sagebrush ecosystems. We conducted a variety of surveys in order to assess the impacts of grazing timing strategies (early summer before peak green-up, mid-summer at peak green-up, and late summer after peak green-up) in conjunction with prescribed fire on avian and small mammal populations in a high-elevation sagebrush ecosystem. Avian surveys resulted in a large detection sample size for three bird species: Brewer's sparrow (Spizella breweri), horned lark (Eremophila alpestris), and vesper sparrow (Pooecetes gramineus). Brewer's sparrows had the lowest number of detections within the mid-summer grazing treatment compared to early and late summer grazing treatments, while horned larks and vesper sparrows had higher detection frequencies within the late summer grazing treatment. Summer and fall sage-grouse (Centrocercus urophasianus) pellet counts revealed that the greatest over-winter and over-summer use by sage-grouse occurred within the early summer grazing treatment with minimal use of burn treatment areas across all grazing treatments. Deer-mice (Peromyscus maniculatus) represented approximately 90 percent of small mammals captured and were most prevalent within the mid-summer grazing treatment. Sagebrush cover was greatest within the mid-summer grazing treatment. We monitored 50 and 103 nests in 2007 and 2008, respectively. The apparent success rate for shrub-obligate nesting species was 58 percent in 2007 and 63 percent in 2008. This research will support management of sagebrush ecosystems by providing public land managers with direct comparisons of wildlife response to management regimes.

  16. A review of experiments comparing systems of grazing management ...

    African Journals Online (AJOL)

    Experiments comparing different systems of grazing management on natural pastures in various parts of the world are reviewed. In experiments in which various rotational systems were tested against continuous grazing, fewer than half revealed pasture improvement relative to continuous grazing. In the majority of ...

  17. Performance and Grazing Pattern of West African Dwarf Sheep to ...

    African Journals Online (AJOL)

    Sixty (60) West African Dwarf sheep managed semi intensively and grazing on natural pastures were used in a study to determine the performance and grazing pattern to seasonal forage supply and quality. The animals were allowed to graze for about 6 hours daily for four months each in the dry and wet seasons, ...

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

    Science.gov (United States)

    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 ...

  19. Longer rest periods for intensive rotational grazing limit diet quality ...

    African Journals Online (AJOL)

    Longer rest periods for intensive rotational grazing limit diet quality of sheep without enhancing environmental benefits. ... This experiment was established to compare three intensive rotational grazing strategies (fast rotation [FR], average 57-day rest; slow rotation [SR], average 114-day rest; and flexible grazing [FX], based ...

  20. Forage patch use by grazing herbivores in a South African grazing ecosystem

    NARCIS (Netherlands)

    Venter, J.A.; Nabe-Nielsen, J.; Prins, H.H.T.; Slotow, R.

    2014-01-01

    Understanding how different herbivores make forage patch use choices explains how they maintain an adequate nutritional status, which is important for effective conservation management of grazing ecosystems. Using telemetry data, we investigated nonruminant zebra (Equus burchelli) and ruminant red

  1. Grazing incidence polarized neutron scattering in reflection ...

    Indian Academy of Sciences (India)

    journal of. January 2012 physics pp. 1–58. Grazing incidence polarized ..... atomic distances, the neutron has an energy which is low compared to molecular binding ...... cores and that of the Co ions in the AF oxide coatings. ...... [32] C Leighton, M R Fitzsimmons, P Yashar, A Hoffmann, J Nogus, J Dura, C F Majkrzak and.

  2. Dietary selection by steers grazing kikuyu

    African Journals Online (AJOL)

    being grazeA for a period of 3,5 days in a four-week rotation, at ... Cattle improve the quality of their diet by actively seeking ... of stem in their diet. This would explain why the stem fraction mad~ no significant contribution to the equation predicting diet~ry selection. A:1unusual fact which emerged is that the animals selected.

  3. 25 CFR 700.722 - Grazing associations.

    Science.gov (United States)

    2010-04-01

    ... recognition by the Commissioner are: (1) The members of the association must be grazing permittees and.... (d) The Commissioner may withdraw his recognition of the association whenever: (1) The majority of... constitution and bylaws. All of the association's livestock will be run under an association brand properly...

  4. Grazing management for Nordic organic dairy farming

    OpenAIRE

    Kuusela, Eeva

    2005-01-01

    The aims of this study were to identify limiting factors and to develop adjusted grazing management for Nordic organic dairy farming conditions. The focus was to combine the aspects of plant, animal and organic production, as they are all involved in organic dairy pastures.

  5. Phosphorus supplementation of Karakul sheep grazing natural ...

    African Journals Online (AJOL)

    The phosphorus (P) status of adult Karakul ewes grazing natural pasture was determined by measuring the P content of blood, saliva, faecal, and bone samples. The ewes were divided into four groups of 20 ewes each, viz. ewes supplemented with P+ and P- which lambed during May and October. All lambs born were ...

  6. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results: High grazing...... as well as in most other European countries, the amount of land covered by semi-natural grassland has decreased dramatically during the 20th century concurrent with the general intensification of the agricultural production. To reverse this trend, actions are being taken in many places to either maintain...

  7. Trends in grazing emission x-ray analysis techniques

    International Nuclear Information System (INIS)

    Grieken, R. van; Tsuji, K.; Injuk, J.

    2000-01-01

    then, the detection limits imposed by the semiconductor industry roadmap can probably not be obtained by tube-excited GEXRF. Th perspectives for tube-excited GE-XRF are thus rather poor. Future developments imply the combination of GEXRF with synchrotron radiation excitation. Grazing-emission particle-induced X-ray emission (GE-PIXE) suffers of similar quantification Problems for material deposited on a carrier, but it makes PIXE a surface-sensitive technique, while normally the protons penetrate some tens of μm in the sample. Similarly, grazing-emission electron probe micro-analysis (GE-EPNIA) allows to selectively analyze particles on a flat carrier, allows surface sensitivities in the nm rather than μ range, and yields, in principle, a spatial resolution for chemical analysis similar to the size of the impinging electron beam, rather than of the electron-excited volume. Both GE-PIXE and GE-EPMA need to be explored more fully in the near future. (author)

  8. Bivalve grazing can shape phytoplankton communities

    Science.gov (United States)

    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.

  9. Grazing livestock are exposed to terrestrial cyanobacteria.

    Science.gov (United States)

    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.

  10. Effect of Grazing Intensity on Some Soil Chemical Characteristics in Gardaneh Zanburi Rangeland of Arsanjan

    Directory of Open Access Journals (Sweden)

    zeinab khademolhosseini

    2016-02-01

    Full Text Available Introduction:Changes caused by grazing on range ecosystem are generally assessed based on the soil conditions and vegetation. Livestock as one of the major elements in range land ecosystems has different effects on different parts of this ecosystem. One of these impacts is excessive livestock grazing capacity which can have different effects on soils and plants in various intensities. Materials and Methods:Gardaneh ZanbooriRangelandis located in Arsanjan in Fars province. This isanareaof mountains, hillsandplains with the maximum height of 2280 meters and minimum height of 1640 meters above sea level. Related areas were separated under three different management methods of enclosure, moderate grazing and heavy grazing. These three areas are considered as symbolic areas of grazing intensity including the reference area where no grazing intensity was observed, the key area where medium to heavy grazing was applied and critical area where heavy grazing was used. These areas were similar in all characteristics such as topography, soil type and rainfall and differed only in their grazing intensity factor. Then, soil samples were collected. Random systematic soil sampling was conducted at two horizons of 0 -15 and 15 -30 cm. Therefore, five profiles in each area (enclosure, moderate grazing and heavy grazing, a total of 15 soil profiles, were excavated and two samples were taken in each profile (one sample from each horizon. Finally, the thirty soil samples were transported to the laboratory. Samples were dried in the air laboratory and passed a two millimeter sieve after smashing. Factors such as N, P, K, OM, EC and PH were measured in each sample In the laboratory, the percentage of P was determined by the Olsen method while the percentage of K was determined using the flamephotometry method. Moreover, N was measured using the Kjeldhal method. C was measured by the Walkley and Black method. The percentage of OM was found by carbon multiplying

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

    Science.gov (United States)

    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.

  12. community participatory sustainable land management byelaw

    African Journals Online (AJOL)

    ACSS

    2014-02-11

    Feb 11, 2014 ... Public SWC investments were largely based Focus on low cost SLM practices on food for work or cash ... land and environmental protection, livestock production and marketing agency, .... Government policy prohibit free grazing, but SWC structures destroyed, trees trampled and .... Nutrient flows and.

  13. Challenges and opportunities in mapping land use intensity globally

    DEFF Research Database (Denmark)

    Kuemmerle, Tobias; Erb, Karlheinz; Meyfroidt, Patrick

    2013-01-01

    Future increases in land-based production will need to focus more on sustainably intensifying existing production systems. Unfortunately, our understanding of the global patterns of land use intensity is weak, partly because land use intensity is a complex, multidimensional term, and partly becau...... challenges and opportunities for mapping land use intensity for cropland, grazing, and forestry systems, and identify key issues for future research....... we lack appropriate datasets to assess land use intensity across broad geographic extents. Here, we review the state of the art regarding approaches for mapping land use intensity and provide a comprehensive overview of available global-scale datasets on land use intensity. We also outline major...

  14. Responses of the functional structure of soil microbial community to livestock grazing in the Tibetan alpine grassland.

    Science.gov (United States)

    Yang, Yunfeng; Wu, Linwei; Lin, Qiaoyan; Yuan, Mengting; Xu, Depeng; Yu, Hao; Hu, Yigang; Duan, Jichuang; Li, Xiangzhen; He, Zhili; Xue, Kai; van Nostrand, Joy; Wang, Shiping; Zhou, Jizhong

    2013-02-01

    Microbes play key roles in various biogeochemical processes, including carbon (C) and nitrogen (N) cycling. However, changes of microbial community at the functional gene level by livestock grazing, which is a global land-use activity, remain unclear. Here we use a functional gene array, GeoChip 4.0, to examine the effects of free livestock grazing on the microbial community at an experimental site of Tibet, a region known to be very sensitive to anthropogenic perturbation and global warming. Our results showed that grazing changed microbial community functional structure, in addition to aboveground vegetation and soil geochemical properties. Further statistical tests showed that microbial community functional structures were closely correlated with environmental variables, and variations in microbial community functional structures were mainly controlled by aboveground vegetation, soil C/N ratio, and NH4 (+) -N. In-depth examination of N cycling genes showed that abundances of N mineralization and nitrification genes were increased at grazed sites, but denitrification and N-reduction genes were decreased, suggesting that functional potentials of relevant bioprocesses were changed. Meanwhile, abundances of genes involved in methane cycling, C fixation, and degradation were decreased, which might be caused by vegetation removal and hence decrease in litter accumulation at grazed sites. In contrast, abundances of virulence, stress, and antibiotics resistance genes were increased because of the presence of livestock. In conclusion, these results indicated that soil microbial community functional structure was very sensitive to the impact of livestock grazing and revealed microbial functional potentials in regulating soil N and C cycling, supporting the necessity to include microbial components in evaluating the consequence of land-use and/or climate changes. © 2012 Blackwell Publishing Ltd.

  15. A search for electron antineutrinos associated with gravitational wave events GW150914 and GW151226 using KamLAND

    NARCIS (Netherlands)

    Gando, A.; Gando, Y.; Hachiya, T.; Hayashi, A.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Karino, Y.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakamura, K.; Obara, S.; Oura, T.; Ozaki, H.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Takai, T.; Tamae, K.; Teraoka, Y.; Ueshima, K.; Watanabe, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T.I.; Berger, B.E.; Fujikawa, B.K.; O'Donnell, T.; Learned, J.G.; Maricic, J.; Sakai, M.; Winslow, L.A.; Krupczak, E.; Ouellet, J.; Efremenko, Y.; Karwowski, H.J.; Markoff, D.M.; Tornow, W.; Detwiler, J.A.; Enomoto, S.; Decowski, M.P.

    2016-01-01

    We present a search, using KamLAND, a kiloton-scale anti-neutrino detector, for low-energy anti-neutrino events that were coincident with the gravitational-wave (GW) events GW150914 and GW151226, and the candidate event LVT151012. We find no inverse beta-decay neutrino events within ±500 s of either

  16. The current status of grazing incidence optics

    International Nuclear Information System (INIS)

    Aschenbach, B.

    1983-01-01

    The developments in the area of grazing incidence optics with emphasis on telescopes for use in X-ray astronomy are reviewed. The performance of existing high-resolution telescopes is outlined and compared with those expected from future missions like ROSAT and AXAF. Starting from the basic principles of X-ray reflection and scattering, an attempt is made to highlight the current understanding of X-ray mirror physics using new theoretical ideas as well as experimental laboratory results. (author)

  17. Seasonality constraints to livestock grazing intensity.

    Science.gov (United States)

    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. © 2017 John Wiley & Sons Ltd.

  18. Grazing livestock are exposed to terrestrial cyanobacteria

    OpenAIRE

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

    2015-01-01

    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 al...

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

    Science.gov (United States)

    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

  20. Common Starlings (Sturnus vulgaris) increasingly select for grazed areas with increasing distance-to-nest.

    Science.gov (United States)

    Heldbjerg, Henning; Fox, Anthony D; Thellesen, Peder V; Dalby, Lars; Sunde, Peter

    2017-01-01

    The abundant and widespread Common Starling (Sturnus vulgaris) is currently declining across much of Europe due to landscape changes caused by agricultural intensification. The proximate mechanisms causing adverse effects to breeding Starlings are unclear, hampering our ability to implement cost-efficient agri-environmental schemes to restore populations to former levels. This study aimed to show how this central foraging farmland bird uses and selects land cover types in general and how use of foraging habitat changes in relation to distance from the nest. We attached GPS-loggers to 17 breeding Starlings at a Danish dairy cattle farm in 2015 and 2016 and analysed their use of different land cover types as a function of distance intervals from the nest and their relative availability. As expected for a central place forager, Starlings increasingly avoided potential foraging areas with greater distance-to-nest: areas ≥ 500 m were selected > 100 times less frequently than areas within 100 m. On average, Starlings selected the land cover category Grazed most frequently, followed by Short Grass, Bare Ground, Meadow and Winter Crops. Starlings compensated for elevated travel costs by showing increasing habitat selection the further they foraged from the nest. Our results highlight the importance of Grazed foraging habitats close to the nest site of breeding Starlings. The ecological capacity of intensively managed farmlands for insectivorous birds like the Starling is decreasing through conversion of the most strongly selected land cover type (Grazed) to the least selected (Winter Crops) which may be further exacerbated through spatial segregation of foraging and breeding habitats.

  1. Common Starlings (Sturnus vulgaris increasingly select for grazed areas with increasing distance-to-nest.

    Directory of Open Access Journals (Sweden)

    Henning Heldbjerg

    Full Text Available The abundant and widespread Common Starling (Sturnus vulgaris is currently declining across much of Europe due to landscape changes caused by agricultural intensification. The proximate mechanisms causing adverse effects to breeding Starlings are unclear, hampering our ability to implement cost-efficient agri-environmental schemes to restore populations to former levels. This study aimed to show how this central foraging farmland bird uses and selects land cover types in general and how use of foraging habitat changes in relation to distance from the nest. We attached GPS-loggers to 17 breeding Starlings at a Danish dairy cattle farm in 2015 and 2016 and analysed their use of different land cover types as a function of distance intervals from the nest and their relative availability. As expected for a central place forager, Starlings increasingly avoided potential foraging areas with greater distance-to-nest: areas ≥ 500 m were selected > 100 times less frequently than areas within 100 m. On average, Starlings selected the land cover category Grazed most frequently, followed by Short Grass, Bare Ground, Meadow and Winter Crops. Starlings compensated for elevated travel costs by showing increasing habitat selection the further they foraged from the nest. Our results highlight the importance of Grazed foraging habitats close to the nest site of breeding Starlings. The ecological capacity of intensively managed farmlands for insectivorous birds like the Starling is decreasing through conversion of the most strongly selected land cover type (Grazed to the least selected (Winter Crops which may be further exacerbated through spatial segregation of foraging and breeding habitats.

  2. Grazing disturbance increases transient but decreases persistent soil seed bank.

    Science.gov (United States)

    Ma, Miaojun; Walck, Jeffrey L; Ma, Zhen; Wang, Lipei; Du, Guozhen

    2018-04-30

    Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole-year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0-5, 5-10, 10-15 cm) and for the whole depth (0-15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs.

  3. Range-wide assessment of livestock grazing across the sagebrush biome

    Science.gov (United States)

    Veblen, Kari E.; Pyke, David A.; Jones, Christopher A.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

    2011-01-01

    Domestic livestock grazing occurs in virtually all sagebrush habitats and is a prominent disturbance factor. By affecting habitat condition and trend, grazing influences the resources required by, and thus, the distribution and abundance of sagebrush-obligate wildlife species (for example, sage-grouse Centrocercus spp.). Yet, the risks that livestock grazing may pose to these species and their habitats are not always clear. Although livestock grazing intensity and associated habitat condition may be known in many places at the local level, we have not yet been able to answer questions about use, condition, and trend at the landscape scale or at the range-wide scale for wildlife species. A great deal of information about grazing use, management regimes, and ecological condition exists at the local level (for individual livestock management units) under the oversight of organizations such as the Bureau of Land Management (BLM). However, the extent, quality, and types of existing data are unknown, which hinders the compilation, mapping, or analysis of these data. Once compiled, these data may be helpful for drawing conclusions about rangeland status, and we may be able to identify relationships between those data and wildlife habitat at the landscape scale. The overall objective of our study was to perform a range-wide assessment of livestock grazing effects (and the relevant supporting data) in sagebrush ecosystems managed by the BLM. Our assessments and analyses focused primarily on local-level management and data collected at the scale of BLM grazing allotments (that is, individual livestock management units). Specific objectives included the following: 1. Identify and refine existing range-wide datasets to be used for analyses of livestock grazing effects on sagebrush ecosystems. 2. Assess the extent, quality, and types of livestock grazing-related natural resource data collected by BLM range-wide (i.e., across allotments, districts and regions). 3. Compile and

  4. An investigation on forage yield capacity of kermes oak (Quercus coccifera L.) and grazing planning of Mediterranean maquis scrublands for traditional goat farming.

    Science.gov (United States)

    Tolunay, Ahmet; Adıyaman, Elif; Akyol, Ayhan; İnce, Duygu; Türkoğlu, Türkay; Ayhan, Veysel

    2014-01-01

    This study investigated grazing capacities of maquis scrubland and preparation principles of grazing management in forest resources. Kermes oak (Quercus coccifera L.), which is widespread as a main shrub species in maquis vegetation in Turkey, and pure hair goats (Capra hircus L.) feeding on shoots and leaves of this shrub were selected for study. The study was conducted in two stages. Green leaf and shoot samples were taken from kermes oaks in the first stage and the amount of green herbage yield (g ∗ m(-1)) and dry matter yield (kg ∗ ha(-1)) that may be obtained per unit area from these samples was identified. The considered amount of dry matter consumed by pure hair goats daily and the number of goats being fed within 1 year on land of 1 ha according to different land coverage rates of kermes oaks (goat head ∗ ha ∗ yr) were calculated. In the second stage, grazing capacities of sample areas where kermes oak spread were identified and compared with the grazing plan prepared by the forestry administration for this area. Forage yield variance according to land coverage rates of maquis scrublands should be considered when determining optimum animal numbers for grazing per area for sustainable goat farming.

  5. An Investigation on Forage Yield Capacity of Kermes Oak (Quercus coccifera L. and Grazing Planning of Mediterranean Maquis Scrublands for Traditional Goat Farming

    Directory of Open Access Journals (Sweden)

    Ahmet Tolunay

    2014-01-01

    Full Text Available This study investigated grazing capacities of maquis scrubland and preparation principles of grazing management in forest resources. Kermes oak (Quercus coccifera L., which is widespread as a main shrub species in maquis vegetation in Turkey, and pure hair goats (Capra hircus L. feeding on shoots and leaves of this shrub were selected for study. The study was conducted in two stages. Green leaf and shoot samples were taken from kermes oaks in the first stage and the amount of green herbage yield (g*m−1 and dry matter yield (kg*ha−1 that may be obtained per unit area from these samples was identified. The considered amount of dry matter consumed by pure hair goats daily and the number of goats being fed within 1 year on land of 1 ha according to different land coverage rates of kermes oaks (goat head*ha*yr were calculated. In the second stage, grazing capacities of sample areas where kermes oak spread were identified and compared with the grazing plan prepared by the forestry administration for this area. Forage yield variance according to land coverage rates of maquis scrublands should be considered when determining optimum animal numbers for grazing per area for sustainable goat farming.

  6. Ecological effects of soil properties and metal concentrations on the composition and diversity of microbial communities associated with land use patterns in an electronic waste recycling region.

    Science.gov (United States)

    Wu, Wencheng; Dong, Changxun; Wu, Jiahui; Liu, Xiaowen; Wu, Yingxin; Chen, Xianbin; Yu, Shixiao

    2017-12-01

    Soil microbes play vital roles in ecosystem functions, and soil microbial communities may be strongly structured by land use patterns associated with electronic waste (e-waste) recycling activities, which can increase the heavy metal concentration in soils. In this study, a suite of soils from five land use types (paddy field, vegetable field, dry field, forest field, and e-waste recycling site) were collected in Longtang Town, Guangdong Province, South China. Soil physicochemical properties and heavy metal concentrations were measured, and the indigenous microbial assemblages were profiled using 16S rRNA high-throughput sequencing and clone library analyses. The results showed that mercury concentration was positively correlated with both Faith's PD and Chao1 estimates, suggesting that the soil microbial alpha diversity was predominantly regulated by mercury. In addition, redundancy analysis indicated that available phosphorus, soil moisture, and mercury were the three major drivers affecting the microbial assemblages. Overall, the microbial composition was determined primarily by land use patterns, and this study provides a novel insight on the composition and diversity of microbial communities in soils associated with e-waste recycling activities. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

  8. CeLAND: search for a 4th light neutrino state with a 3 PBq 144Ce-144Pr electron antineutrino generator in KamLAND

    Energy Technology Data Exchange (ETDEWEB)

    Gando, A; Gando, Y; Hayashida, S; Ikeda, H; Inoue, K; Ishidoshiro, K; Ishikawa, H; Koga, M; Matsuda, R; Matsuda, S; Mitsui, T; Motoki, D; Nakamura, K; Oki, Y; Otani, M; Shimizu, I; Shirai, J; Suekane, F; Suzuki, A; Takemoto, Y; Tamae, K; Ueshima, K; Watanabe, H; Xu, BD; Yamada, S; Yamauchi, Y; Yoshida, H; Cribier, M; Durero, M; Fischer, V; Gaffiot, J; Jonqueres, N; Kouchner, A; Lasserre, T; Leterme, D; Letourneau, A; Lhuillier, D; Mention, G; Rampal, G; Scola, L; Veyssiere, C; Vivier, M; Yala, P; Berger, BE; Kozlov, A; Banks, T; Dwyer, D; Fujikawa, BK; Han, K; Kolomensky, YG; Mei, Y; O' Donnell, T; Decowski, P; Markoff, DM; Yoshida, S; Kornoukhov, VN; Gelis, TVM; Tikhomirov, GV; Learned, JG; Maricic, J; Matsuno, S; Milincic, R; Karwowski, HJ; Efremenko, Y; Detwiler, A; Enomoto, S

    2017-05-12

    The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq (75-100 kCi scale) 144Ce-144Pr antineutrino beta-source deployed at the center or next to a large low-background liquid scintillator detector. The antineutrino generator will be produced by the Russian reprocessing plant PA Mayak as early as 2014, transported to Japan, and deployed in the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) as early as 2015. KamLAND's 13 m diameter target volume provides a suitable environment to measure the energy and position dependence of the detected neutrino flux. A characteristic oscillation pattern would be visible for a baseline of about 10 m or less, providing a very clean signal of neutrino disappearance into a yet-unknown, sterile neutrino state. This will provide a comprehensive test of the electron dissaperance neutrino anomalies and could lead to the discovery of a 4th neutrino state for Δm$2\\atop{new}$ ≳ 0.1 eV2 and sin2(2θnew) > 0.05.

  9. Data resources for range-wide assessment of livestock grazing across the sagebrush biome

    Science.gov (United States)

    Assal, T.J.; Veblen, K.E.; Farinha, M.A.; Aldridge, Cameron L.; Casazza, Michael L.; Pyke, D.A.

    2012-01-01

    The data contained in this series were compiled, modified, and analyzed for the U.S. Geological Survey (USGS) report "Range-Wide Assessment of Livestock Grazing Across the Sagebrush Biome." This report can be accessed through the USGS Publications Warehouse (online linkage: http://pubs.usgs.gov/of/2011/1263/). The dataset contains spatial and tabular data related to Bureau of Land Management (BLM) Grazing Allotments. We reviewed the BLM national grazing allotment spatial dataset available from the GeoCommunicator National Integrated Land System (NILS) website in 2007 (http://www.geocommunicator.gov). We identified several limitations in those data and learned that some BLM State and/or field offices had updated their spatial data to rectify these limitations, but maintained the data outside of NILS. We contacted appropriate BLM offices (State or field, 25 in all) to obtain the most recent data, assessed the data, established a data development protocol, and compiled data into a topologically enforced dataset throughout the area of interest for this project (that is, the pre-settlement distribution of Greater Sage-Grouse in the Western United States). The final database includes three spatial datasets: Allotments (BLM Grazing Allotments), OUT_Polygons (nonallotment polygons used to ensure topology), and Duplicate_Polygon_Allotments. See Appendix 1 of the aforementioned report for complete methods. The tabular data presented here consists of information synthesized by the Land Health Standard (LHS) analysis (Appendix 2), and data obtained from the BLM Rangeland Administration System (http://www.blm.gov/ras/). In 2008, available LHS data for all allotments in all regions were compiled by BLM in response to a Freedom of Information Act (FOIA) request made by a private organization. The BLM provided us with a copy of these data. These data provided three major types of information that were of interest: (1) date(s) (if any) of the most recent LHS evaluation for each

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

    Science.gov (United States)

    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.

  11. Ecological Effects of Grazing in the Northern Tianshan Mountains

    Directory of Open Access Journals (Sweden)

    Xiaotao Huang

    2017-11-01

    Full Text Available Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC grazing model, we explored the effects of grazing on grassland net primary productivity (NPP, evapotranspiration (ET and water use efficiency (WUE from 1979 to 2012 along an elevation gradient in the northern Tianshan Mountains. The NPP, ET and WUE values were generally lower under the grazing scenario than under the ungrazed scenario; the differences between the grazing and ungrazed scenarios showed increasing trends over time; and distinct spatial heterogeneity in these differences was observed. Distinct decreases in NPP and WUE under the grazing scenario mainly occurred in regions with high livestock consumption. The decrease in ET was greater in mountainous areas with high grazing intensity due to decreased transpiration and increased surface runoff. This study contributes to a better understanding of the ecological effects of grazing along an elevation gradient in the northern Tianshan Mountains and provides data to support the scientific management of grassland ecosystems.

  12. Livestock grazing and the desert tortoise in the Mojave Desert

    Science.gov (United States)

    Oldemeyer, John L.

    1994-01-01

    A large part of the Mojave Desert is not in pristine condition, and some current conditions can be related to past grazing-management practices. No information could be found on densities of the desert tortoise (Gopherus agassizii) or on vegetative conditions of areas that had not been grazed to allow managers a comparison of range conditions with data on tortoises. Experimental information to assess the effect of livestock grazing on tortoises is lacking, and researchers have not yet examined whether the forage that remains after grazing is sufficient to meet the nutritional needs of desert tortoises.

  13. A Systematic Review of Wild Burro Grazing Effects on Mojave Desert Vegetation, USA

    Science.gov (United States)

    Abella, Scott R.

    2008-06-01

    Wild burros ( Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.

  14. Effect of supplement level on herbage intake and feeding behaviour of Italian Brown cows grazing on Alpine pasture

    Directory of Open Access Journals (Sweden)

    D. Villa

    2010-01-01

    Full Text Available Summer grazing of dairy cows on mountain pastures often leads to a fall in production or in body condition when the pasture is not adequately supplemented with concentrate feeds (Malossini et al., 1992; Bovolenta et al., 1998. An abundant use of concentrates may result into a reduction of herbage intake according to a substitution rate mechanism (Faverdin et al., 1991. The aim of this trial was to evaluate the effect of the supplementation level on herbage intake, milk yield and feeding behaviour (time spent grazing and ruminating of dairy cows at pasture, combining the use of an electronic bitemeter and a double marker method for the estimation of intake.

  15. Iodine-129 in thyroids of grazing animals

    International Nuclear Information System (INIS)

    Ballad, R.V.; Holman, D.W.; Hennecke, E.W.; Johnson, J.E.; Manuel, O.K.; Nicholson, L.M.

    1976-01-01

    A combination of neutron activation and mass spectrometry has been used to determine the concentrations of fissiogenic 129 I and stable 127 I in thyroids of grazing animals and in mineral iodine. The 129 I/ 127 I ratios are lowest in mineral iodine and in a given area lower in cow thyroids than in deer thyroids. Near saturation levels of mineral iodine in commercial feeds and salt licks may account for differences in the 129 I levels of cows and deer. Values of the 129 I/ 127 I ratio in deer appear to vary inversely with the iodine concentration of the thyroid. (author)

  16. Grazing and Rangeland Development for Livestock Production. A Handbook for Volunteers. Agriculture Technology for Developing Countries. Appropriate Technologies for Development. Reprint R-47.

    Science.gov (United States)

    Sprague, Howard B.; And Others

    This handbook, developed for training Peace Corps volunteers, reviews the basic principles that underlie sound grazing land management and indicates the application of these principles for livestock production in the tropics and subtropics. The handbook is made up of three technical series bulletins. The first bulletin covers management of…

  17. Milk production, grazing behavior and nutritional status of dairy cows grazing two herbage allowances during winter

    Directory of Open Access Journals (Sweden)

    Miguel Ruiz-Albarran

    2016-03-01

    Full Text Available Winter grazing provides a useful means for increasing the proportion of grazed herbage in the annual diet of dairy cows. This season is characterized by low herbage growth rate, low herbage allowance, and low herbage intake and hence greater needs for supplements to supply the requirements of lactating dairy cows. The aim of this study was to determine the influence of herbage allowance (HA offered to autumn calving dairy cows grazing winter herbage on milk production, nutritional status, and grazing behavior. The study took 63 d using 32 multiparous Holstein-Friesian dairy cows. Prior to experimental treatment, milk production averaged 20.2 ± 1.7 kg d-1, body weight was 503 ± 19 kg, and days in milking were 103 ± 6. Experimental animals were randomly assigned to two treatments according to HA offered above ground level: low (17 kg DM cow-1 d-1 vs. high HA (25 kg DM cow¹ d¹. All cows were supplemented with grass silage supplying daily 6.25 and 4.6 kg DM of concentrate (concentrate commercial plus high corn moisture. Decreasing HA influenced positively milk production (+25%, milk protein (+20 kg, and milk fat (+17 kg per hectare; however no effects on milk production per cow or energy metabolic status were observed in the cows. In conclusion, a low HA showed to be the most significant influencing factor on milk and milk solids production per hectare in dairy cows grazing restricted winter and supplemented with grass silage and concentrate; but no effect on the milk production per cow was found.

  18. Modelling nitrous oxide emissions from grazed grassland systems

    International Nuclear Information System (INIS)

    Wang Junye; Cardenas, Laura M.; Misselbrook, Tom H.; Cuttle, Steve; Thorman, Rachel E.; Li Changsheng

    2012-01-01

    Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N 2 O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N 2 O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N 2 O emissions increased as the grazing intensity increased. - Highlights: ► Parameterisation of grazing system using grazing intensity. ► Modification of UK D NDC for the UK soil and weather conditions. ► Validation of the UK D NDC against measured data of N 2 O emissions in three UK sites. ► Estimating influence of animal grazing practises on N 2 O emissions. - Grazing system was parameterised using grazing intensity and UK-DNDC model was modified and validated against measured data of N 2 O emissions in three UK sites.

  19. A 100-Year Review: A century of change in temperate grazing dairy systems.

    Science.gov (United States)

    Roche, J R; Berry, D P; Bryant, A M; Burke, C R; Butler, S T; Dillon, P G; Donaghy, D J; Horan, B; Macdonald, K A; Macmillan, K L

    2017-12-01

    From 1917 to 2017, dairy grazing systems have evolved from uncontrolled grazing of unimproved pastures by dual-purpose dairy-beef breeds to an intensive system with a high output per unit of land from a fit-for-purpose cow. The end of World War I signaled significant government investments in agricultural research institutes around the world, which coincided with technological breakthroughs in milk harvesting and a recognition that important traits in both plants and animals could be improved upon relatively rapidly through genetic selection. Uptake of milk recording and herd testing increased rapidly through the 1920s, as did the recognition that pastures that were rested in between grazing events yielded more in a year than those continuously grazed. This, and the invention and refinement of the electric fence, led to the development of "controlled" rotational grazing. This, in itself, facilitated greater stocking rates and a 5 to 10% increase in milk output per hectare but, perhaps more importantly, it allowed a more efficient use of nitrogen fertilizer, further increasing milk output/land area by 20%. Farmer inventions led to the development of the herringbone and rotary milking parlors, which, along with the "unshortable" electric fence and technological breakthroughs in sperm dilution rates, allowed further dairy farm expansion. Simple but effective technological breakthroughs in reproduction ensured that cows were identified in estrus early (a key factor in maintaining the seasonality of milk production) and enabled researchers to quantify the anestrus problem in grazing herds. Genetic improvement of pasture species has lagged its bovine counterpart, but recent developments in multi-trait indices as well as investment in genetic technologies should significantly increase potential milk production per hectare. Decades of research on the use of feeds other than pasture (i.e., supplementary feeds) have provided consistent milk production responses when the

  20. Mountain pastures of Qilian Shan: plant communities, grazing impact and degradation status (Gansu province, NW China)

    Science.gov (United States)

    Baranova, Alina; Schickhoff, Udo; Shunli, Wang; Ming, Jin

    2015-04-01

    Qilian Mountains are the water source region for the low arid reaches of HeiHe river basin (Gansu province, NW China). Due to overstocking and overgrazing during the last decades adverse ecological ef¬fects, in particular on soil properties and hydrological cycle, are to be expected in growing land areas. Vegetation cover is very important to prevent erosion process and to sustain stable subsurface runoff and ground water flow. The aim of this research is to identify plant communities, detecting grazing-induced and spatially differentiated changes in vegetation patterns, and to evaluate status of pasture land degradation.The study area is located in the spring/autumn pasture area of South Qilian Mountains between 2600-3600 m a.s.l., covering five main vegetation types: spruce forest, alpine shrubland, shrubby grassland, mountain grassland, degraded mountain grassland. In order to analyze gradual changes in vegetation patterns along altitudinal and grazing gradients and to classify related plant communities, quantitative and qualitative relevé data were collected (coverage, species composition, abundance of unpalatable plants, plant functional types, etc.). Vegetation was classified using hierarchical cluster analyses. Indirect Detrended Correspondence Analysis (DCA) was used to analyze variation in relationships between vegetation, environmental factors, and grazing impact. According to DCA results, distribution of the plant communities was strongly affected by altitude and exposition. Grassland floristic gradients showed greater dependence on grazing impact, which correlated contrarily with soil organic content, soil moisture and pH. Highest numbers of species richness and alpha diversity were detected in alpine shrubland vegetation type. Comparing the monitoring data for the recent nine years, a trend of deterioration, species successions and shift in dominant species becomes obvious. Species indicating degrading site environmental conditions were identified

  1. How grazing affects soil quality of soils formed in the glaciated northeastern United States.

    Science.gov (United States)

    Cox, Alissa H; Amador, José A

    2018-02-21

    Historically, much of the New England landscape was converted to pasture for grazing animals and harvesting hay. Both consumer demand for local sustainably produced food, and the number of small farms is increasing in RI, highlighting the importance of characterizing the effects livestock have on the quality of pasture soils. To assess how livestock affect pasture on Charlton and Canton soils series in RI, we examined soil quality in farms raising beef cattle (Bos taurus), sheep (Ovis aries), and horses (Equus ferus caballus), using hayed pastures as a control. We sampled three pastures per livestock type and three control hayed pastures in May, August, and October 2012. Hay fields and pastures grazed by sheep had statistically significant (P soil quality than pastures grazed by beef cattle or horses. This was driven by parameters including penetration resistance, bulk density, aggregate stability, and infiltration rate. Hayfields also showed higher soil quality measures than grazed pastures for organic matter content and active C. In addition, significant differences in nitrate and phosphate concentrations were observed among livestock types. Respiration and infiltration rates, pH, and ammonium concentrations, on the other hand, did not differ significantly among pasture types. When all soil quality indicators in this study were weighed equally, soil quality scores followed the order: hay > sheep > beef cattle > horses. The results of our study provide baseline data on the effect different types of livestock have on pasture soil quality in RI, which may be useful in making sound land use and agricultural management decisions.

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

    Science.gov (United States)

    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...

  3. Day and night grazing by cattle in the Sahel

    NARCIS (Netherlands)

    Ayantunde, A.A.; Fernandez-Rivera, S.; Hiernaux, P.H.; Keulen, van H.; Udo, H.M.J.

    2002-01-01

    The influence of night grazing on feeding behavior, nutrition and performance of cattle was studied. Twenty-four steers weighing 367 kg (SD = 76) grazed either from 0900 to 1900 (day grazers), 2100 to 0700 (night grazers) or 0900 to 1900 and 2400 to 0400 (day-and-night grazers) during 13 weeks. Four

  4. Resilience of soils and vegetation subjected to different grazing ...

    African Journals Online (AJOL)

    The resilience of rangeland soils and vegetation to different levels of grazing is still poorly understood. A study was conducted to determine the recovery of a rangeland grazed at different intensities and allowed a two-year rest period. The following treatments were applied to 0.5 hectare plots: 0, 4, 8 and 16 heifers per ...

  5. Soil contamination of plant surfaces from grazing and rainfall interactions

    International Nuclear Information System (INIS)

    Hinton, T.G.; Stoll, J.M.; Tobler, L.

    1995-01-01

    Contaminants often attach to soil particles, and their subsequent environmental transport is largely determined by processes that govern soil movement. We examined the influence of grazing intensity on soil contamination of pastures. Four different grazing densities of sheep were tested against an ungrazed control plot. Scandium concentrations were determined by neutron activation analysis and was used as a tracer of soil adhesion on vegetation. Soil loadings ( g soil kg -1 dry plant) increased 60% when grazing intensity was increased by a factor of four (p 0.003). Rain and wind removed soil from vegetation in the ungrazed control plots, but when grazing sheep were present, an increase in rain from 0.3 to 9.7 mm caused a 130% increase in soil contamination. Multiple regression was used to develop an equation that predicts soil loadings as a function of grazing density, rainfall and wind speed (p = 0.0001, r 2 = 0.78). The model predicts that if grazing management were to be used as a tool to reduce contaminant intake from inadvertent consumption of resuspended soil by grazing animals, grazing densities would have to be reduced 2.5 times to reduce soil loadings by 50%. (author)

  6. White clover regenerative ability under N fertilizing and grazing

    Directory of Open Access Journals (Sweden)

    Josip Leto

    2008-12-01

    Full Text Available Recently, ecological and economic factors in milk and meat production stimulate use of legumes and grass-legumes mixtures, with zero or minimum mineral N as alternative to grass monoculture with high rate of mineral N. Research objective was to examine the effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S on white clover: growing points number, stolon lenght, stolon dry weight, dry matter yield and clover contribution to total annual herbage production. N150 significantly reduced the growing points number, stolon length and stolon dry weight for more than 70 % compared to N0. Grazing treatment affected stolon population density only in interaction with N application because of N150 significantly reduced white clover population density only in sheep grazing. S-treatment had higher clover DM yield (0.21 t ha-1 than C-treatment (0.13 t ha-1. N0 had higher clover DM yield (0.25 t ha-1 than N150 (0.09 t ha-1. However, the interaction grazing management x N rate was significant for clover DM yield and clover contribution to total DM yield. N150 reduced both parameters for 80 % only in sheep grazing while difference in DM yield and clover contribution to total DM yield between grazing treatment was recorded only in N0 Sheep grazing increased DM yield for 150 % and clover contribution for 99 % compared to cattle grazing.

  7. Grass species selection patterns on rotationally-grazed Dohne ...

    African Journals Online (AJOL)

    Herbaceous species preference was studied during autumn and winter periods of occupation, on rotationally-grazed Dohne Sourveld, at four different stocking rates. Reports on species selection by cattle and sheep grazing together. Illustrates with graphsLanguage: English. Keywords: Grass species; Herbage availibility; ...

  8. Transformation of a savanna grassland by drought and grazing | O ...

    African Journals Online (AJOL)

    The relative effects of drought and heavy grazing on the floristic composition, population size and and structure, and basal cover of an African savanna grassland were differentiated by comparing changes over eight years over eight years, which included a severe drought year, across a gradient of grazing history. Drought ...

  9. The evaluation of four Eragrostis curvula ecotypes with grazing sheep.

    African Journals Online (AJOL)

    There were no significant differences in the dry matter production and chemical composition of the clipped samples of the ecotypes. Keywords: afrikaans; chemical composition; dry matter production; ecotypes; eragrostis curvula; grazing; live mass; live mass gains; open rotational grazing system; production; sheep; south ...

  10. Mixed farming in a grazing reserve in Northern Nigeria | Babalobi ...

    African Journals Online (AJOL)

    Nigeria's main pastoral development strategy is the settlement of pastoralists in grazing reserves. The goal of the strategy is to turn such nomadic pastoralists into mixed farmers who will take up crop farming to supplement livestock farming. Using the Bobi Grazing Reserve, Niger State, Nigeria as case study, the attainment ...

  11. Review: Behavior and daily grazing patterns of cattle

    NARCIS (Netherlands)

    Gregorini, P.; Tamminga, S.; Gunther, S.A.

    2006-01-01

    Grazing ruminants consume their food in discrete grazing events. The frequency and distribution of these events depend on the current physiological state of the animal and its environment. Within a small spatio-temporal scale, foraging decisions such as when to begin, which frequency, and how to

  12. Environmental Assessment of Beale AFB Grazing Lease Program

    Science.gov (United States)

    2012-12-01

    Beale AFB will use livestock (cattle, sheep and goats ) on its properties throughout the year as needed for the control of noxious weeds, reduction...initiating a wildfire. California Farm Bureau Federation policy recognizes that grazing is the most practical and environmentally acceptable way to...Site Monitoring Well Installation and Annual Targeted Goat Grazing Project, Placer County, California. 21 September 2011.  

  13. Possibilities and constraints for grazing in high output dairy systems

    NARCIS (Netherlands)

    Hennessy, D.; Delaby, L.; Pol, van den A.; Shalloo, L.

    2015-01-01

    In temperate and oceanic regions, grazed grass is the lowest cost feed available for milk production. In other regions, grazed grass is less important but can contribute to the diet of livestock. Within high output systems the interaction between the animal and sward is challenging for a host of

  14. The grazing index method of range condition assessment | du Toit ...

    African Journals Online (AJOL)

    Owing to the difficulty of examining succession theory in the Karoo, it is suggested the ecological index method (EIM), be replaced by the grazing index method (GIM), through the introduction of grazing index values (GIV) for Karoo plant species. The GIM may provide more acceptable range condition scores and more ...

  15. Forage selection and performance of sheep grazing dry annual range.

    NARCIS (Netherlands)

    Ridder, de N.; Benjamin, R.W.; Keulen, van H.

    1986-01-01

    During 114 days of grazing, sheep grazing a dry annual pasture in Israel selected the fine fraction available with a higher nutritive value. As this fraction became depleted and feed quality dropped, organic matter intake dropped from 1.73 to 0.75 kg/sheep/d. Sheep lost weight, body condition and

  16. Livestock Grazing as a Driver of Vernal Pool Ecohydrology

    Science.gov (United States)

    Michaels, J.; McCarten, N. F.

    2017-12-01

    Vernal pools are seasonal wetlands that host rare plant communities of high conservation priority. Plant community composition is largely driven by pool hydroperiod. A previous study found that vernal pools grazed by livestock had longer hydroperiods compared with pools excluded from grazing for 10 years, and suggests that livestock grazing can be used to protect plant diversity. It is important to assess whether observed differences are due to the grazing or due to water balance variables including upland discharge into or out of the pools since no a priori measurements were made of the hydrology prior to grazing. To address this question, in 2016 we compared 15 pools that have been grazed continuously and 15 pools that have been fenced off for over 40 years at a site in Sacramento County. We paired pools based on abiotic characteristics (size, shape, slope, soil type) to minimize natural variation. We sampled vegetation and water depth using Solinst level loggers. We found that plant diversity and average hydroperiod was significantly higher in the grazed pools. We are currently measuring groundwater connectivity and upland inputs in order to compare the relative strength of livestock grazing as a driver of hydroperiod to these other drivers.

  17. Effect of mowing and grazing on ramet emergence of Leymus ...

    African Journals Online (AJOL)

    user

    2011-03-21

    Mar 21, 2011 ... experiment was conducted in the spring of 2004 to investigate the effects on the surface soil temperature caused by mowing, grazing and grazing exclusion, and the influence of these factors on the ramets emergence characteristics. The primary effect of the treatments was significant changes in.

  18. Vegetation patterns and nutrients in relation to grazing pressure and ...

    African Journals Online (AJOL)

    A major challenge confronting managers of extensive grazing systems is uneven use of erbaceous forage plants by livestock. The concentration of grazing in preferred areas or around foci points (e.g. water points) eventually results in adverse impacts in soil nutrients, vegetation structure, production and composition.

  19. Grasses grazed by springbok and sheep | R. | African Journal of ...

    African Journals Online (AJOL)

    Grazing habits were determined by analysis of rumina from slaughtered springbok and sheep where springbok grazed together with Merino sheep in False Upper Karoo and together with Dorper sheep in Kalahari Thornveld. Results show that in both veld types, grass constituted about 39 percent of the dry mass intake of ...

  20. Low-damage high-throughput grazing-angle sputter deposition on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.-T.; Gajek, M.; Raoux, S. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Casu, E. A. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Politecnico di Torino, Turin 10129 (Italy)

    2013-07-15

    Despite the prevalence of sputter deposition in the microelectronics industry, it has seen very limited applications for graphene electronics. In this letter, we report systematic investigation of the sputtering induced damages in graphene and identify the energetic sputtering gas neutrals as the primary cause of graphene disorder. We further demonstrate a grazing-incidence sputtering configuration that strongly suppresses fast neutral bombardment and retains graphene structure integrity, creating considerably lower damage than electron-beam evaporation. Such sputtering technique yields fully covered, smooth thin dielectric films, highlighting its potential for contact metals, gate oxides, and tunnel barriers fabrication in graphene device applications.

  1. Low-damage high-throughput grazing-angle sputter deposition on graphene

    International Nuclear Information System (INIS)

    Chen, C.-T.; Gajek, M.; Raoux, S.; Casu, E. A.

    2013-01-01

    Despite the prevalence of sputter deposition in the microelectronics industry, it has seen very limited applications for graphene electronics. In this letter, we report systematic investigation of the sputtering induced damages in graphene and identify the energetic sputtering gas neutrals as the primary cause of graphene disorder. We further demonstrate a grazing-incidence sputtering configuration that strongly suppresses fast neutral bombardment and retains graphene structure integrity, creating considerably lower damage than electron-beam evaporation. Such sputtering technique yields fully covered, smooth thin dielectric films, highlighting its potential for contact metals, gate oxides, and tunnel barriers fabrication in graphene device applications

  2. Low-damage high-throughput grazing-angle sputter deposition on graphene

    Science.gov (United States)

    Chen, C.-T.; Casu, E. A.; Gajek, M.; Raoux, S.

    2013-07-01

    Despite the prevalence of sputter deposition in the microelectronics industry, it has seen very limited applications for graphene electronics. In this letter, we report systematic investigation of the sputtering induced damages in graphene and identify the energetic sputtering gas neutrals as the primary cause of graphene disorder. We further demonstrate a grazing-incidence sputtering configuration that strongly suppresses fast neutral bombardment and retains graphene structure integrity, creating considerably lower damage than electron-beam evaporation. Such sputtering technique yields fully covered, smooth thin dielectric films, highlighting its potential for contact metals, gate oxides, and tunnel barriers fabrication in graphene device applications.

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

    Directory of Open Access Journals (Sweden)

    Mariecia D Fraser

    Full Text Available 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

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

    Science.gov (United States)

    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...

  5. Effects of grazing system on production and parasitism of dairy breed heifers and steers grazing wet marginal grasslands

    DEFF Research Database (Denmark)

    Kristensen, Troels; Thamsborg, S.M.; Andersen, Refsgaard

    2006-01-01

    Production and endoparasitism of first grazing season Holstein heifers and steers were investigated over two grazing seasons. Studies were conducted on low-lying peaty soil. In year 2000, 40 animals were included in a 2x2 factorial, replicated experiment with two sexes (steers v. heifers) and two...

  6. The effects of burning and grazing on soil carbon dynamics in managed Peruvian tropical montane grasslands

    Directory of Open Access Journals (Sweden)

    V. Oliver

    2017-12-01

    Full Text Available Montane tropical soils are a large carbon (C reservoir, acting as both a source and a sink of CO2. Enhanced CO2 emissions originate, in large part, from the decomposition and losses of soil organic matter (SOM following anthropogenic disturbances. Therefore, quantitative knowledge of the stabilization and decomposition of SOM is necessary in order to understand, assess and predict the impact of land management in the tropics. In particular, labile SOM is an early and sensitive indicator of how SOM responds to changes in land use and management practices, which could have major implications for long-term carbon storage and rising atmospheric CO2 concentrations. The aim of this study was to investigate the impacts of grazing and fire history on soil C dynamics in the Peruvian montane grasslands, an understudied ecosystem, which covers approximately a quarter of the land area in Peru. A density fractionation method was used to quantify the labile and stable organic matter pools, along with soil CO2 flux and decomposition measurements. Grazing and burning together significantly increased soil CO2 fluxes and decomposition rates and reduced temperature as a driver. Although there was no significant effect of land use on total soil C stocks, the combination of burning and grazing decreased the proportion of C in the free light fraction (LF, especially at the lower depths (10–20 and 20–30 cm. In the control soils, 20 % of the material recovered was in the free LF, which contained 30 % of the soil C content. In comparison, the burnt–grazed soil had the smallest recovery of the free LF (10 % and a significantly lower C content (14 %. The burnt soils had a much higher proportion of C in the occluded LF (12 % compared to the not-burnt soils (7 % and there was no significant difference among the treatments in the heavy fraction (F ( ∼  70 %. The synergistic effect of burning and grazing caused changes to the soil C dynamics. CO2

  7. Key sources and seasonal dynamics of greenhouse gas fluxes from yak grazing systems on the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Liu, Yang; Yan, Caiyu; Matthew, Cory; Wood, Brennon; Hou, Fujiang

    2017-01-01

    Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine meadows, dung patches, manure heaps and yak night pens, on the Qinghai-Tibetan Plateau. We also estimated the total annual global warming potential (GWP, CO2-equivalents) from family farm grazing yaks using our measured results and other published data. In this study, GHG fluxes per unit area from night pens and composting manure heaps were higher than from dung patches and alpine meadows. Increased moisture content and surface temperature of soil and manure were major factors increasing CO2 and CH4 fluxes. High contributions of CH4 and N2O (21.1% and 44.8%, respectively) to the annual total GWP budget (334.2 tonnes) strongly suggest these GHG other than CO2 should not be ignored when estimating GWP from the family farm grazing yaks on the Qinghai-Tibetan Plateau for the purposes of determining national and regional land use policies or compiling global GHG inventories.

  8. Effects of grazing strategy on limiting nitrate leaching in grazed grass-clover pastures on coarse sandy soil

    DEFF Research Database (Denmark)

    Hansen, Elly Møller; Eriksen, Jørgen; Søegaard, Karen

    2012-01-01

    -term mean. The experiment was initiated in a 4-yr-old grass-clover sward in south Denmark. Three treatments were as follows grazing only (G), spring cut followed by grazing (CG) and both spring and autumn cuts with summer grazing (CGC). Nitrate leaching was calculated by extracting water isolates from 80 cm......Urinations of ruminants on grazed pastures increase the risk of nitrate leaching. The study investigated the effect of reducing the length of the grazing season on nitrate leaching from a coarse sandy, irrigated soil during 2006–2007 and 2007–2008. In both years, precipitation was above the long...... depth using ceramic suction cups. Because of considerable variation in measured nitrate concentrations, the 32 installed suction cups per treatment were insufficient to reveal differences between treatments. However, weighted nitrate leaching estimations for G, CG and CGC showed estimated mean nitrate N...

  9. Grazing Affects Exosomal Circulating MicroRNAs in Cattle

    Science.gov (United States)

    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 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 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

  10. Figure and finish of grazing incidence mirrors

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Church, E.L.

    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

  11. Poultry performance in different grazing densities: forage characteristics, losses due to grazing and feed intake

    Directory of Open Access Journals (Sweden)

    Luciano Cristiano França

    2014-02-01

    Full Text Available Morphological characteristics of three forage species grazed by rustic poultry in stocking were evaluated. Coast-cross fodder, kikuyu grass, and stylosanthes were planted in 33-m2 paddocks with two densities (m2/animal: D1 = 3m2/animal and D2 = 1m2/animal. The design was a randomized complete block with a 3 x 2 factorial (three grasses and two densities and three replications. Grass canopy height, grass mass, morphological composition (leaf, stem, and dead material, losses due to grazing, poultry weight gain and consumption, and concentrate feed conversion ratio and efficiency were evaluated. At the end of the experiment, forage and leaves masses were considered low to stylosanthes in D2 (0.28 to 0.03 kg/m2 and to kikuyu grass in D1 (0.13 to 0.05 kg/m2 and in D2 (0.11 and 0.03 kg/m2, respectively. In addition, the grass canopy height was considered low for stylosanthes (6.50 cm that could jeopardize the entry of new poultry lot. The three grass species had similar weight gain and revealed better results for 3m²/ chicken (3.20 kg/animal. Coast-cross fodder, kikuyu grass, and stylosanthes, with some exceptions, can be considered suitable for grazing fattening poultry at 3m2/animal at the evaluated time of the year (autumn.

  12. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  13. Plasma protein loss associated with gastrointestinal parasitism in grazing sheep.

    Science.gov (United States)

    Yakoob, A Y; Holmes, P H; Parkins, J J; Armour, J

    1983-01-01

    Some pathophysiological effects of parasitic gastroenteritis in two groups of lambs grazing paddocks either heavily or lightly contaminated with trichostrongyle larvae were investigated between July and October 1980. The leak of plasma protein was measured on three occasions at pasture using 51chromic chloride. Total faecal output was measured indirectly using chromic oxide. Losses of 51chromic chloride-labelled plasma protein into the gastrointestinal tract were significantly higher in the lambs grazing the heavily contaminated pasture than in those grazing lightly infected ground in both July and August. The increased plasma losses were associated with high faecal egg counts, hypoalbuminaemia and elevated levels of plasma pepsinogen.

  14. Aplanatic grazing incidence diffraction grating: a new optical element

    International Nuclear Information System (INIS)

    Hettrick, M.C.

    1986-01-01

    We present the theory of a grazing incidence reflection grating capable of imaging at submicron resolution. The optic is mechanically ruled on a spherical or cylindrical surface with varied groove spacings, delivering diffraction-limited response and a wide field of view at a selected wavelength. Geometrical aberrations are calculated on the basis of Fermat's principle, revealing significant improvements over a grazing incidence mirror. Aplanatic and quasi-aplanatic versions of the grating have applications in both imaging and scanning microscopes, microprobes, collimators, and telescopes. A 2-D crossed system of such gratings, similar to the grazing incidence mirror geometry of Kirkpatrick and Baez, could potentially provide spatial resolutions of --200 A

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

    Science.gov (United States)

    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. The effect of grazing on cow mortality in Danish dairy herds

    DEFF Research Database (Denmark)

    Burow, Elke; Thomsen, Peter Thorup; Sørensen, Jan Tind

    2011-01-01

    The effect of summer grazing in large Danish dairy herds and certain management characteristics of grazing were studied for their impact on dairy cow mortality. Mortality data (from the Danish Cattle Database) from 391 Danish dairy herds (>100 cows) were combined with information from...... a questionnaire survey of grazing procedures on these herds in 2008. In all, 131 of the herds were identified as summer grazing and 260 as zero-grazing herds. The mortality was affected by an interaction of summer grazing and milking system. The risk of a cow dying was reduced to 46% in a grazing compared...... and pasture was associated with increased cow mortality....

  17. Cattle grazing and its long-term effects on sedge meadows

    Science.gov (United States)

    Middleton, Beth

    2004-01-01

    Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to support shrubs and trees, and eventually it is no longer a wetland (Middleton, 1999; Middleton and others, 2004). These old ideas of how vegetation changes (succession) are no longer accepted. Wetland succession should be thought of as a cycle, with natural disturbance driving the changes, depending on the needs of the species. Succession is not something that changes a wetland into something that is not a wetland (Egler, 1978; van der Valk, 1981; Middleton and others, 1991; Klinger, 1996; Middleton, 1999).As an example of how disturbance changes wetlands, I have studied sedge meadows that have become invaded by shrubs after cattle (Bos sp.) have grazed them, in the Lodi Marsh State Natural Area, Wisconsin. Cattle disturbances allowed shrubs to invade sedge meadows, but the cattle also grazed on the shrubs, which kept them small. After the cows were removed, the plant species changed in the sedge meadow from the original sedges (fig. 1), to sedges mixed with growing small shrubs, and eventually to tall shrubs with very small amounts of sedge, called “shrub carr” (Middleton, 2002a). Even though there has been a succession of plant types, the meadows, which began as wetlands, have remained wetlands. The settlers originally found the sedge meadows to be open “sedge” lands and not shrubby. The settlers cut the sedges by hand to feed the cattle. Whitetailed deer (Odocoileus virginianus), though probably not bison (Bison bison), grazed these sedge meadows (Middleton 2002a).Subsequent studies have explored methods to control invasive shrubs to restore the biodiversity of

  18. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    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

  19. Changes in soil carbon cycling accompanying conversion of row-crop fields to grazing dairy pastures

    Science.gov (United States)

    Thompson, A.; Kramer, M. G.; Hill, N.; Machmuller, M. B.; Cyle, K.

    2011-12-01

    Increasingly, the dairy industry in the eastern US is transitioning from total confinement dairy systems (TCD) toward pasture-based, management intensive grazing dairy (MiGD) systems. This transition is driven by the fact that MiGDs require substantially less operating capital and are more economically efficient than TCD systems. Consequently, the impact of this transition and shift in land-use practice on carbon dynamics may be considerable. Land-use in a Management intensive Grazing Dairy (MiGD) system is fundamentally different than conventional confinement dairies and conventional no-till pastures. The forage system involves rotational grazing at optimal digestibility, when the plants are immature (~20-days) and consequently protein-rich. MiGD cows spend >90% of their time in the field and deposit > 90% of their waste directly to the soil surface. Thus, little above ground plant residues are directly returned to the soil, but rather substantial C inputs derive from bovine manure. We sampled a MiGD-chronosequence of row-crop to MiGD conversion established in 2007 in eastern Georgia. All soils across the MiGD-chronosequence, all occur in relative (40 km) close proximity to one another, are deep, well-drained, fine and fine sandy loam Ultisols formed on Coastal Plain sediments. Prior to MiGD established, the soils were farmed for > 50 yrs using conventional tillage techniques. Our current sampling to 1m depths captures fields at 0, 2, 3, and 5 yrs since conversion. Total soil carbon (C) and the carbon concentration of the clay fraction increased following conversion, with the greatest increases occurring between 3 and 5 yrs since conversion. These C increases were limited to the upper 40cm of the soil, with minimal change occurring at depth. Characterization of the protein and ligand content of these soils via 13C NMR and chemolytic techniques as a function of soil particle density and size is in progress and will be presented along with estimates of carbon

  20. Phosphorus and the grazing ruminant. 2. The effects of ...

    African Journals Online (AJOL)

    Department of Animal Science, University of Stellenbosch, Stellenbosch. The effects of .... rosis, severely impaired locomotion and therefore grazing behaviour ..... Studies in mineral metabolism. XXXVII. The influence of variations in the dietary ...

  1. Small mammal communities on cattle and game grazing areas in ...

    African Journals Online (AJOL)

    Small mammal communities on cattle and game grazing areas in Namibia. ... small mammal communities on two differently managed farmlands (cattle and game farm) in Namibia over the course of one year. ... AJOL African Journals Online.

  2. Animal health management practices in zero grazing dairy units in ...

    African Journals Online (AJOL)

    Animal health management practices in zero grazing dairy units in Arusha City, Tanzania. ... African Journal of Food, Agriculture, Nutrition and Development ... findings, majority (84.6%) of the cow's enclosures were of poor hygiene.

  3. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    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...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum 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....

  4. Ecological status of species on grazing gradients on the shallow ...

    African Journals Online (AJOL)

    Ecological status of species on grazing gradients on the shallow soils of the western ... Open Access DOWNLOAD FULL TEXT ... Vegetation data were gathered in such a way that those of different successional stages could be identified.

  5. The effects of land use types and soil depth on soil properties of ...

    African Journals Online (AJOL)

    The effects of land use types and soil depth on soil properties of Agedit watershed, Northwest Ethiopia. ... immediate intervention to protect the remnant forests and to replenish the degraded soil properties for sustainable agricultural productivity. Keywords: cultivation, deforestation, grazing, land management, soil fertility ...

  6. Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

    Science.gov (United States)

    Alchin, Bruce; Williams, Wendy

    2015-04-01

    In arid and semi-arid Australia, the central role of healthy soil ecosystems in broad-acre grazing lands may be attributed to the widespread presence of cyanobacterial crusts. In terms of soil nutrient cycling and stability their role is particularly crucial in a climate dominated by annual dry seasons and variable wet seasons. In this study, we aimed to measure the contribution of cyanobacteria to soil nutrient cycling under contrasting levels of disturbance associated with grazing management. Field sampling was carried out on six paired sites (twelve properties) located across an east-west 3,000 km transect that covered different rangeland types on grazing properties in northern Australia (Queensland, Northern Territory and Western Australia). At each location paired sites were established and two different management systems were assessed, cell-paddock rotations (25-400 ha) and continuous grazing (200-2,000 ha). Cyanobacterial soil crusts were recorded from all of the twelve sites and cyanobacteria with the capacity to fix nitrogen were found at ten of the twelve sites. The overall diversity of cyanobacteria varied from three to ten species under any type of grazing system. As field work was conducted in the dry season, it is likely that the diversity may be greater in the wet season than the initial data may indicate. The average cyanobacterial soil crust cover across soil surfaces, between grass tussocks, during the dry season was estimated to be 50.9% and, 42.6% in the early wet season. This reflected longer established crust cover (dry season) versus newly established crusts. There was a high level of variability in the biomass of cyanobacteria however; the grazing system did not have any marked effect on the biomass for any one rangeland type. The grazing system differences did not appear to significantly influence the diversity at any location except on a floodplain in the Pilbara (WA). Biological nitrogen fixation by cyanobacteria was recorded at all

  7. Evaluating pasture and soil allowance of manganese for Kajli rams grazing in semi-arid environment.

    Science.gov (United States)

    Khan, Zafar Iqbal; Ahmad, Kafeel; Ashraf, Muhammad; Naqvi, Syed Ali Hassan; Seidavi, Alireza; Akram, Nudrat Aisha; Laudadio, Vito; Tufarelli, Vincenzo

    2015-03-01

    The current research on the manganese (Mn) transfer from soil to plant as well as to grazing Kajli rams in the form of sampling periods was carried out under semi-arid environmental conditions. Forage, soil and blood plasma samples were collected during 4 months of the year after a 1-month interval, and Mn concentrations were assessed after wet digestion using an atomic absorption spectrophotometer. Results showed that Mn concentration in soil ranged from 48.28 to 59.44 mg/kg, with incoherent augment and decline across sampling periods, and effect of sampling period on soil Mn was also found to be significant (P soil appeared higher than the critical value and sufficient for forage crop requirement. The Mn concentration in forage ranged between 24.8 and 37.2 mg/kg, resulting deficient based on the requirement allowance of Mn for livestock grazing animals, therein with almost unchanged forage Mn concentration. The Mn values in blood plasma of rams varied from 0.066 to 0.089 mg/l, with a consistent increase based on sampling period, and the effect of sampling periods on plasma Mn was found to be highly significant (P soil and plant species amassing capability on the transport of Mn in the soil-plant-animal system. Results indicated a much higher accumulation rate at the sampling characterized by vegetation dominated by legumes in comparison to grasses, crop residues and mixed pasture and a pronounced seasonal supply of Mn at the four sampling period of grazing land of diverse botanical composition.

  8. Rotation grazing as a conservation management tool : Vegetation changes after six years of application in a salt marsh ecosystem

    NARCIS (Netherlands)

    Lagendijk, D. D. Georgette; Howison, Ruth A.; Esselink, Peter; Ubels, Richard; Smit, Christian

    2017-01-01

    Grazing is commonly used in conservation to promote biodiversity, but the search for a grazing management regime that optimises biodiversity is still ongoing. Rotation grazing, where grazing is followed by a relatively long period of non-grazing, is a relative new tool in conservation management,

  9. Population Dynamics and Transcriptomic Responses of Chorthippus albonemus (Orthoptera: Acrididae to Herbivore Grazing Intensity

    Directory of Open Access Journals (Sweden)

    Xinghu Qin

    2017-11-01

    Full Text Available Livestock grazing can trigger outbreaks of insect pests in steppe ecosystems of Inner Mongolia in China. However, the physiological responses of the grasshopper Chorthippus albonemus to grazing are not well-understood. Here we investigated the effects of sheep grazing on the population dynamics and transcriptomic response of C. albonemus. We collected the insects three times (about 20 days apart in 1.33-ha plots in which there were no grazing, light grazing, moderate grazing, heavy grazing, or overgrazing. Our results showed that continuous grazing significantly decreased plant biomass and influenced plant succession. Total insect species diversity significantly declined along the grazing intensity gradient and over time. Results of the first two collections of C. albonemus indicated that moderate grazing significantly increased the abundance of C. albonemus. However, abundance was significantly decreased in plots that were overgrazed, possibly because of food stress and environmental pressures. Under moderate grazing, betA and CHDH genes were significantly upregulated in C. albonemus. In response to higher grazing intensity, upregulated genes included those involved in serine-type peptidase activity, anatomical structure development, and sensory organ development; downregulated genes included those involved in the structural constituents of the ribosome and ribosome processes. Genes strongly upregulated in response to heavy grazing pressure included adaptive genes such as those encoding ankyrin repeat domain-containing protein and HSP. These findings improve our understanding of the role of the transcriptome in C. albonemus population response to livestock grazing and may provide useful targets for grasshopper control.

  10. The effects of potential changes in United States beef production on global grazing systems and greenhouse gas emissions

    International Nuclear Information System (INIS)

    Dumortier, Jerome; Hayes, Dermot J; Carriquiry, Miguel; Elobeid, Amani; Fabiosa, Jacinto F; Dong, Fengxia; Du Xiaodong; Martin, Pamela A; Mulik, Kranti

    2012-01-01

    We couple a global agricultural production and trade model with a greenhouse gas model to assess leakage associated with modified beef production in the United States. The effects on emissions from agricultural production (i.e., methane and nitrous oxide emissions from livestock and crop management) as well as from land-use change, especially grazing system, are assessed. We find that a reduction of US beef production induces net carbon emissions from global land-use change ranging from 37 to 85 kg CO 2 -equivalent per kg of beef annualized over 20 years. The increase in emissions is caused by an inelastic domestic demand as well as more land-intensive cattle production systems internationally. Changes in livestock production systems such as increasing stocking rate could partially offset emission increases from pasture expansion. In addition, net emissions from enteric fermentation increase because methane emissions per kilogram of beef tend to be higher globally. (letter)

  11. The importance of agricultural lands for Himalayan birds in winter.

    Science.gov (United States)

    Elsen, Paul R; Kalyanaraman, Ramnarayan; Ramesh, Krishnamurthy; Wilcove, David S

    2017-04-01

    The impacts of land-use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low-intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low-intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low-intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land-use classes, but only 4 species were unique to primary forests. Low-, medium-, and high-intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low-intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land-use intensity increased, especially in high-intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification-especially increased grazing-will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low-intensity agricultural

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

    Science.gov (United States)

    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

  13. Morphogenesis in guinea grass pastures under rotational grazing strategies

    Directory of Open Access Journals (Sweden)

    Denise Baptaglin Montagner

    2012-04-01

    Full Text Available This study was conducted in order to evaluate the morphogenetic and structural characteristics of guinea grass cv. Mombasa under three post-grazing heights (intense - 30 cm, lenient - 50 cm and variable - 50 in spring-summer and 30 cm in autumn-winter when sward light interception reached 95% during regrowth. Post-grazing heights were allocated to experimental units (0.25 ha in a completely randomized block design with three replications. Post-grazing heights affected only leaf elongation rate and the number of live leaves. Pastures managed with variable post-grazing height showed higher leaf elongation rate in the summer of 2007. This management strategy also resulted in a higher number of live leaves. During the spring of 2006, plants showed lower leaf elongation rate, leaf appearance rate and number of live leaves, and greater phyllochron and leaf lifespan. In contrast, during the summer of 2007, the leaf appearance rate, leaf elongation rate, number of live leaves, and final leaf length were greater while phyllochron, stem elongation rate, and leaf senescence rate were lower. The management of the guinea grass cv. Mombasa with intense or variable post-grazing height throughout the year seems to represent an interesting management target, in terms of leaf appearance rate and number of live leaves.

  14. Semi-arid grassland bird responses to patch-burn grazing and drought

    Science.gov (United States)

    Skagen, Susan K.; Augustine, David J.; Derner, Justin D.

    2018-01-01

    As grassland birds of central North America experience steep population declines with changes in land use, management of remaining tracts becomes increasingly important for population viability. The integrated use of fire and grazing may enhance vegetation heterogeneity and diversity in breeding birds, but the subsequent effects on reproduction are unknown. We examined the influence of patch-burn grazing management in shortgrass steppe in eastern Colorado on habitat use and reproductive success of 3 grassland bird species, horned lark (Eremophila alpestris), lark bunting (Calamospiza melanocorys), and McCown’s longspur (Rhynchophanes mccownii), at several spatial scales during 2011 and 2012. Although no simple direct relationship to patch-burn grazing treatment existed, habitat selection depended on precipitation- and management-induced vegetation conditions and spatial scale. All species selected taller-than-expected vegetation at the nest site, whereas at the territory scale, horned larks and McCown’s longspurs selected areas with low vegetation height and sparse cover of tall plants (taller than the dominant shortgrasses). Buntings nested primarily in unburned grassland under average rainfall. Larks and longspurs shifted activity from patch burns during average precipitation (2011) to unburned pastures during drought (2012). Daily survival rate (DSR) of nests varied with time in season, species, weather, and vegetation structure. Daily survival rate of McCown’s longspur nests did not vary with foliar cover of relatively tall vegetation at the nest under average precipitation but declined with increasing cover during drought. At the 200-m scale, increasing cover of shortgrasses, rather than taller plant species, improved DSR of larks and longspurs. These birds experience tradeoffs in the selection of habitat at different spatial scales: tall structure at nests may reduce visual detection by predators and provide protection from sun, wind, and rain, yet

  15. Greenhouse gas fluxes of grazed and hayed wetland catchments in the U.S. Prairie Pothole Ecoregion

    Science.gov (United States)

    Finocchiaro, Raymond G.; Tangen, Brian A.; Gleason, Robert A.

    2014-01-01

    Wetland catchments are major ecosystems in the Prairie Pothole Region (PPR) and play an important role in greenhouse gases (GHG) flux. However, there is limited information regarding effects of land-use on GHG fluxes from these wetland systems. We examined the effects of grazing and haying, two common land-use practices in the region, on GHG fluxes from wetland catchments during 2007 and 2008. Fluxes of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2), along with soil water content and temperature, were measured along a topographic gradient every other week during the growing season near Ipswich, SD, USA. Closed, opaque chambers were used to measure fluxes of soil and plant respiration from native sod catchments that were grazed or left idle, and from recently restored catchments which were seeded with native plant species; half of these catchments were hayed once during the growing season. Catchments were adjacent to each other and had similar soils, soil nitrogen and organic carbon content, precipitation, and vegetation. When compared with idle catchments, grazing as a land-use had little effect on GHG fluxes. Likewise, haying had little effect on fluxes of CH4 and N2O compared with non-hayed catchments. Haying, however, did have a significant effect on combined soil and vegetative CO2 flux in restored wetland catchments owing to the immediate and comprehensive effect haying has on plant productivity. This study also examined soil conditions that affect GHG fluxes and provides cumulative annual estimates of GHG fluxes from wetland catchment in the PPR.

  16. A catchment-scale model to predict spatial and temporal burden of E. coli on pasture from grazing livestock.

    Science.gov (United States)

    Oliver, David M; Bartie, Phil J; Louise Heathwaite, A; Reaney, Sim M; Parnell, Jared A Q; Quilliam, Richard S

    2018-03-01

    Effective management of diffuse microbial water pollution from agriculture requires a fundamental understanding of how spatial patterns of microbial pollutants, e.g. E. coli, vary over time at the landscape scale. The aim of this study was to apply the Visualising Pathogen &Environmental Risk (ViPER) model, developed to predict E. coli burden on agricultural land, in a spatially distributed manner to two contrasting catchments in order to map and understand changes in E. coli burden contributed to land from grazing livestock. The model was applied to the River Ayr and Lunan Water catchments, with significant correlations observed between area of improved grassland and the maximum total E. coli per 1km 2 grid cell (Ayr: r=0.57; pE. coli burden between seasons in both catchments, with summer and autumn predicted to accrue higher E. coli contributions relative to spring and winter (PE. coli loading to land as driven by stocking density and livestock grazing regimes. Resulting risk maps therefore provide the underpinning evidence to inform spatially-targeted decision-making with respect to managing sources of E. coli in agricultural environments. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  17. Land Cover

    Data.gov (United States)

    Kansas Data Access and Support Center — The Land Cover database depicts 10 general land cover classes for the State of Kansas. The database was compiled from a digital classification of Landsat Thematic...

  18. The changing structure and tree composition in the traditionally grazed forests in the parish of Stenbrohult, southern Sweden

    OpenAIRE

    Nilsson, Sven

    2006-01-01

    The formerly grazed forest (utmark) was the dominant land use on most farms in southern Sweden until about 100 years ago. Here I describe the changed structure and tree species composition over time of the utmark on three farms owned by the church in the central part of Stenbrohult. In this area Carl Linnaeus spent his first 20 summers until 1728. The study is based on old forest management plans, other old documents, published and unpublished pollen analyses from 3 small bogs, tree ages on a...

  19. Mulighedernes land?

    DEFF Research Database (Denmark)

    Munck Petersen, Rikke

    2001-01-01

    Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark.......Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark....

  20. A new spectrometer for grazing incidence X-ray fluorescence for the characterization of Arsenic implants and Hf based high-k layers

    International Nuclear Information System (INIS)

    Ingerle, D.; Meirer, F.; Zoeger, N.; Pepponi, G.; Giubertoni, D.; Steinhauser, G.; Wobrauschek, P.; Streli, C.

    2010-01-01

    Grazing Incidence X-ray Fluorescence Analysis (GIXRF) is a powerful technique for depth-profiling and characterization of thin layers in depths up to a few hundred nanometers. By measurement of fluorescence signals at various incidence angles Grazing Incidence X-ray Fluorescence Analysis provides information on depth distribution and total dose of the elements in the layers. The technique is very sensitive even in depths of a few nanometers. As Grazing Incidence X-ray Fluorescence Analysis does not provide unambigous depth profile information and needs a realistic input depth profile for fitting, in the context of the EC funded European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis (ANNA) Grazing Incidence X-ray Fluorescence Analysis is used as a complementary technique to Secondary Ion Mass Spectrometry (SIMS) for the characterization of Ultra Shallow Junctions (USJ). A measuring chamber was designed, constructed and tested to meet the requirements of Grazing Incidence X-ray Fluorescence Analysis. A measurement protocol was developed and tested. Some results for As implants as well as Hf based high k layers on Silicon are shown. For the determination of the bulk As content of the wafers, Instrumental Neutron Activation Analysis has also been applied for comparison.

  1. Horse grazing systems: understory biomass and plant biodiversity of a Pinus radiata stand

    Directory of Open Access Journals (Sweden)

    Antonio Rigueiro-Rodríguez

    2012-02-01

    Full Text Available Horse grazing systems may affect productivity and biodiversity of understory developed under Pinus radiata D. Don silvopastoral systems, while acting as a tool to reduce the risk of fire. This study compared continuous and rotational grazing systems effect upon biomass, fractions of stem, sprouts, leaves and woody parts of Ulex europaeus L. and alpha (Species Richness, Shannon-Wiener and beta (Jaccard and Magurran biodiversity for a period of four years in a P. radiata silvopastoral system. The experiment consisted of a randomized block design of two treatments (continuous and rotational grazing. Biomass, and species abundances were measured - biodiversity metrics were calculated based on these results for a two years of grazing and two years of post-grazing periods. Both continuous and rotational grazing systems were useful tools for reducing biomass and, therefore, fire risk. The rotational grazing system caused damage to the U. europaeus shrub, limiting its recovery once grazing was stopped. However, the more intensive grazing of U. europaeus plants under rotational had a positive effect on both alpha and beta biodiversity indexes due to the low capacity of food selection in the whole plot rather than continuous grazing systems. Biomass was not affected by the grazing system; however the rotational grazing system is more appropriate to reduce U. europaeus biomass and therefore forest fire risk at a long term and to enhance pasture biodiversity than the continuous grazing system.

  2. Electron-electron coincidence spectroscopies at surfaces

    International Nuclear Information System (INIS)

    Stefani, G.; Iacobucci, S.; Ruocco, A.; Gotter, R.

    2002-01-01

    In the past 20 years, a steadily increasing number of electron-electron coincidence experiments on atoms and molecules have contributed to a deeper understanding of electron-electron correlation effects. In more recent years this technique has been extended to the study of solid surfaces. This class of one photon IN two electrons OUT experiments will be discussed with an emphasis on grazing incidence geometry, that is expected to be particularly suited for studying surfaces. The crucial question of which is the dominant mechanism that leads to ejection of pairs of electron from the surface will be addressed. It will be shown that, depending on the kinematics chosen, the correlated behaviour of the pairs of electrons detected might be singled out from independent particle one

  3. X-ray grazing incidence diffraction from multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tixier, S.; Boeni, P.; Swygenhoven, H. van; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Grazing incidence scattering geometries using synchrotron radiation have been applied in order to characterise the roughness profiles and the structural coherence of multilayers. The lateral correlation length of the roughness profiles was evaluated using diffuse reflectivity in the `out of plane` geometry. This type of measurement is the only diffuse reflectivity technique allowing large lateral momentum transfer. It is typically suitable for correlation lengths smaller than 1000 A. The lateral structural coherence length of Ni{sub 3}Al/Ni multilayers as a function of the layer thickness was obtained by grazing incidence diffraction (GID). 3 figs., 1 ref.

  4. Partially coherent X-ray wavefront propagation simulations including grazing-incidence focusing optics.

    Science.gov (United States)

    Canestrari, Niccolo; Chubar, Oleg; Reininger, Ruben

    2014-09-01

    X-ray beamlines in modern synchrotron radiation sources make extensive use of grazing-incidence reflective optics, in particular Kirkpatrick-Baez elliptical mirror systems. These systems can focus the incoming X-rays down to nanometer-scale spot sizes while maintaining relatively large acceptance apertures and high flux in the focused radiation spots. In low-emittance storage rings and in free-electron lasers such systems are used with partially or even nearly fully coherent X-ray beams and often target diffraction-limited resolution. Therefore, their accurate simulation and modeling has to be performed within the framework of wave optics. Here the implementation and benchmarking of a wave-optics method for the simulation of grazing-incidence mirrors based on the local stationary-phase approximation or, in other words, the local propagation of the radiation electric field along geometrical rays, is described. The proposed method is CPU-efficient and fully compatible with the numerical methods of Fourier optics. It has been implemented in the Synchrotron Radiation Workshop (SRW) computer code and extensively tested against the geometrical ray-tracing code SHADOW. The test simulations have been performed for cases without and with diffraction at mirror apertures, including cases where the grazing-incidence mirrors can be hardly approximated by ideal lenses. Good agreement between the SRW and SHADOW simulation results is observed in the cases without diffraction. The differences between the simulation results obtained by the two codes in diffraction-dominated cases for illumination with fully or partially coherent radiation are analyzed and interpreted. The application of the new method for the simulation of wavefront propagation through a high-resolution X-ray microspectroscopy beamline at the National Synchrotron Light Source II (Brookhaven National Laboratory, USA) is demonstrated.

  5. Effect of grazing on the cow welfare of dairy herds evaluated by a multidimensional welfare index

    DEFF Research Database (Denmark)

    Burow, E.; Rousing, T.; Thomsen, P. T.

    2013-01-01

    Structural development in the prime sector has led to increasing herd sizes and new barn systems, followed by less summer grazing for dairy cows in Denmark. Effects of grazing on single welfare measures in dairy cows - for example, the presence of integument alterations or mortality - have been......) inspired multidimensional dairy cow welfare assessment protocol, the within-herd effect of summer grazing compared with winter barn housing in Danish dairy herds with cubicle free-stall systems for the lactating cows. Our hypothesis was that cow welfare in dairy herds was better during summer grazing than...... out to be more beneficial than few daily grazing hours (range average above 9 to 21 h) for the welfare of the dairy herds. In conclusion, this study reports a positive within-herd effect of summer grazing on dairy cow welfare, where many daily grazing hours were more beneficial than few daily grazing...

  6. Herbage availability €rs a stress factor on grazed Coastcross II ...

    African Journals Online (AJOL)

    ) relationships for Coastcross ll Bermuda grass grazed for four consecutive summer periods by young growing beef cattle. Stocking rate affected the daily. LWG/animal through its influence on herbage availability. Rota- tional grazing showed a ...

  7. Impact of Graze-­‐Out in Hard Red Winter Wheat Production

    OpenAIRE

    Neupane, Diwash; Moss, Charles B.

    2014-01-01

    We investigate the relationship between wheat graze-­‐out and cattle-­‐wheat price ratio and moisture level and examine the impact of graze-­‐out on wheat yield in major wheat-­‐producing states in US. Results indicate that cattle-­‐wheat price ratio and moisture level affect farmers’ graze out decision and graze-­‐out have significant impact on wheat yield.

  8. Wilderness and woodland ranchers in California: A total income case study of public grazing permits and their impacts on conservation

    Science.gov (United States)

    Oviedo Pro, J. L.; Huntsinger, L.; Campos, P.; Caparros, A.

    2009-04-01

    Mediterranean woodlands in California are managed as agro-silvo-pastoral systems producing a number of commercial products as well as a huge variety of environmental services, including private amenities for the landowner. In many parts of the woodlands, grazing on government owned (public) lands has traditionally had an important role in private ranching. In recent decades the risk of conversion to alternative uses (such as urban development or vineyards) has threatened these woodlands due to the increasing opportunity costs of capital. Understanding the economy of these woodlands and the potential effects of public grazing policies on the total income perceived by the landowner is crucial when considering strategies attempting to slow or stop land use change. However, traditional cash-flow analyses are lacking crucial information needed to understand all the elements that have an important role in the economic decisions that landowners make about their woodlands. For more than half a century, the use of public lands by private ranchers has been one of the most controversial debates in the American west. Wilderness conservationist groups have denounced grazing as destructive and argue for the removal of any kind of livestock. Ranchers have fought for their right to hold public grazing leases, arguing that they are crucial for the continuity of private ranching and consequently for the conservation of extensive rangeland habitat that otherwise could be converted to alternative uses. In this study, we apply the Agroforestry Accounting System (AAS) methodology to a California oak woodland case study to estimate the total private income generated in an accounting period. The presented case study is characterized by a household economy with self-employed labour and with part of the grazing dependent on public land leases. The AAS methodology extends traditional cash-flow analysis in order to estimate the total private income that would accurately explain the woodland

  9. Influence of grazing regimes on cattle nutrition and performance and vegetation dynamics in Sahelian rangelands

    NARCIS (Netherlands)

    Ayantunde, A.A.

    1998-01-01

    In the West African Sahel, common herd management practices such as night grazing and corralling influence time available for grazing. When animals are used to deposit manure in the cropping fields, conflicts often arise between the need for animals to graze long enough for adequate feed

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

    Science.gov (United States)

    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; ...

  11. Livestock grazing has minimal effect on the species richness and ...

    African Journals Online (AJOL)

    The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined ...

  12. Ingestive Behaviour of Grazing Ewes Given Two Levels of Concentrate

    African Journals Online (AJOL)

    It was expected that concentrate supplementation would reflect directly on forage intake owing to the substitution effect, which causes sheep where the supplement supplied a small proportion of net energy requirement, to have a greater grazing intensity. The two breeds differed in the time spent ruminating or lying, with the ...

  13. Radiobiological problems concerning grazing animals following the Chernobyl accident

    International Nuclear Information System (INIS)

    Prister, B.S.; Lazarev, N.M.; Romanov, L.M.

    1997-01-01

    Chernobyl accident took place on April 26 1986, which was the beginning of the grazing season, when there was not enough fodder on the farms and the cattle was grazed on the open territory. Therefore grazing animal-breeding was the most radioactively affected branch. The consumption of contaminated fodder and surface contamination with radioactive precipitation caused the accumulation of considerable ingested doses in the organisms of animals (up to 1 GY). Radioactive damage caused to the thyroid by the selective accumulation of radioiodine (mainly 131 I) is of particular attention. Cumulative doses of thyroid irradiation in mammals were much higher than for the other organs. Thus, in cows during their grazing on the contaminated pastures outside 30-km zone the ratio of ingested doses of the thyroid and whole body was 130:1 and more, therefore, radiation effects could have a certain negative effect, concerning the agricultural animals in the zone of accidental release influence. Accumulated ingested doses in the thyroid of cows on the contaminated territory in a number of cases caused the complete destruction of the thyroid (doses above 600 Gy), which provided the loss of milk productivity and reproductive qualities of the animals. Lower doses caused the functional disturbances, which in most cases have been levelled during the years after the accident

  14. Bacterial production, protozoan grazing, and mineralization in stratified Lake Vechten

    NARCIS (Netherlands)

    Bloem, J.

    1989-01-01

    The role of heterotrophic nanoflagellates (HNAN, size 2-20 μm) in grazing on bacteria and mineralization of organic matter in stratified Lake Vechten was studied.

    Quantitative effects of manipulation and fixation on HNAN were checked. Considerable losses were caused by

  15. Stability, resilience and animal production in continuously grazed ...

    African Journals Online (AJOL)

    The Jones-Sandland model, popularly used in southern Africa, may be criticised because it ignores firstly the long-term effects of grazing intensity on the acceptability and productivity of pasture or veld, and secondly possible discontinuities in the animal performance - stocking rate relationship. A mathematical model is ...

  16. Influence of sward characteristics on grazing behaviour and short ...

    African Journals Online (AJOL)

    Relative to temperate systems, there has been few reported detailed assessments of sward characteristics and associated grazing behavior from natural and ... in highly heterogeneous pastures has the potential to provide integrated (sward, animal, management) strategies for sustainable livestock production in Nigeria.

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

    Directory of Open Access Journals (Sweden)

    Carlos Cáceres

    Full Text Available 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.

  18. The national grazing strategy of the Republic of South Africa ...

    African Journals Online (AJOL)

    The White Paper on Agricultural Policy, tabled in May 1984, made reference to the alarming deterioration of natural rangelands and led to the drawing up of the National Grazing Strategy (NGS), released to parliament in May 1985, which was endorsed by the Department of Agriculture and accepted in its entirety by the ...

  19. The impact of grazing on forage quality of the herbaceous ...

    African Journals Online (AJOL)

    Reports on research conducted in the Mamoro cork oak forest of Morocco to describe the impacts of sheep grazing in March, April, May and June of 1987 and 1988 on seasonal changes in forage quality of the herbaceous vegetation. The study showed that trends in herbage quality were related mainly to plant maturity.

  20. Grazing on Regeneration Sites Encourages Pine Seedling Growth

    Science.gov (United States)

    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...

  1. The Occurrence and Toxicity of Indospicine to Grazing Animals

    Directory of Open Access Journals (Sweden)

    Mary T. Fletcher

    2015-07-01

    Full Text Available Indospicine is a non-proteinogenic amino acid which occurs in Indigofera species with widespread prevalence in grazing pastures across tropical Africa, Asia, Australia, and the Americas. It accumulates in the tissues of grazing livestock after ingestion of Indigofera. It is a competitive inhibitor of arginase and causes both liver degeneration and abortion. Indospicine hepatoxicity occurs universally across animal species but the degree varies considerably between species, with dogs being particularly sensitive. The magnitude of canine sensitivity is such that ingestion of naturally indospicine-contaminated horse and camel meat has caused secondary poisoning of dogs, raising significant industry concern. Indospicine impacts on the health and production of grazing animals per se has been less widely documented. Livestock grazing Indigofera have a chronic and cumulative exposure to this toxin, with such exposure experimentally shown to induce both hepatotoxicity and embryo-lethal effects in cattle and sheep. In extensive pasture systems, where animals are not closely monitored, the resultant toxicosis may well occur after prolonged exposure but either be undetected, or even if detected not be attributable to a particular cause. Indospicine should be considered as a possible cause of animal poor performance, particularly reduced weight gain or reproductive losses, in pastures where Indigofera are prevalent.

  2. Carcass mass gains of steers grazing star grass, with different ...

    African Journals Online (AJOL)

    Carcass mass gains of steers grazing dryland Cynodon aethiopicus cv. No. 2 Star grass pastures during the growing season were determined for each of 16 treatments comprising four levels of nitrogen fertilisation in combination with four overlapping sets of stocking rates. The treatments were repeated over four growing ...

  3. Research note: Grazing-index method procedures of vegetation ...

    African Journals Online (AJOL)

    In the past, veld condition in the Karoo was assessed using the ecological index methods. This recently changed to the graxing-index method on account of the of the differently estimated grazing-index values being used. The principles governing the method of survey remain the same. The method employs ...

  4. Phosphorus and the grazing ruminant. 1. The effect of ...

    African Journals Online (AJOL)

    M.Sc.-tesis,. Universiteit Stellenbosch. DUDZINSKI, M.L. & ARNOLD, G.W., 1973. Comparison of diets of sheep and cattle grazing together on sown pastures on the southern tablelands of New South Wales by principal components analysis. Aust. J. Agric. Res. 24, 899. DU TOlT, P.J., MALAN, AI. & ROSSOUW, S.D., 1930.

  5. Effects of UV-B irradiated algae on zooplankton grazing

    NARCIS (Netherlands)

    Lange, de H.J.; Lürling, M.F.L.L.W.

    2003-01-01

    We tested the effects of UV-B stressed algae on grazing rates of zooplankton. Four algal species ( Chlamydomonas reinhardtii, Cryptomonas sp., Scenedesmus obliquus and Microcystis aeruginosa) were used as food and fed to three zooplankton species ( Daphnia galeata, Bosmina longirostris and

  6. Grazing animal husbandry based on sustainable nutrient management

    NARCIS (Netherlands)

    Hermans, C.; Vereijken, P.H.

    1995-01-01

    Sustainable husbandry systems for grazing animals (cattle and sheep) can be achieved by sustainable nutrient management (SNM). This implies the tuning of inputs to outputs of nutrients, to achieve and maintain optimum ranges of agronomically wanted and ecologically acceptable reserves of single

  7. Improved grazing activity of dairy heifers in shaded tropical grasslands

    Directory of Open Access Journals (Sweden)

    Andréia Cristina Tavares de Mello

    Full Text Available ABSTRACT: Trees in the production systems can effectively reduce hot weather-induced stress in the Brazilian Midwest. High temperatures cause changes in animals daily routine, and trees into pastures can promote benefits. The aim of this research was to evaluate the behavior of dairy heifers in silvopastoral systems in the state of Mato Grosso, Brazil. A herd of 24 crossbreed heifers (3/4 and 7/8 Holstein/Zebu, 350kg average weight, was evaluated over three seasons. Piatã grass was managed under three shade levels: full-sun, moderate-shade, and intensive-shade provided by 10 to 12m high Eucalyptus trees. Behavior data were collected every 15 minutes from 8:30h to 16h. Shade availability significantly impacted heifer behavior, mainly affecting grazing frequency and time during the hottest hours. Grazing behavior was affected by shade levels during the different seasons. Heifers showed preferred grazing times. Heifers in the intensive-shade system visited shady areas during the hottest hours throughout the seasons. Heifers in the full sun-system avoided grazing during the warmer times, ceasing feeding activities. Our results from the Brazilian Midwest showed that shade availability causes breed heifers to change their daily routine.

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

    Science.gov (United States)

    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

  9. Surface - atmosphere exchange of ammonia over grazed pasture

    NARCIS (Netherlands)

    Plantaz, M.A.H.G.

    1998-01-01

    This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.
    Ammonia exchange

  10. Effects of rainfall, competition and grazing on flowering of ...

    African Journals Online (AJOL)

    Birds, hares and small antelope consumed 10-50% of the flowers. Size-class distributions indicated that little recent recruitment had taken place on a ranch where palatable plants were scarce and where O. sinuatum flower production was severely depressed by grazing sheep.Language: English. Keywords: Asteraceae ...

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

    Science.gov (United States)

    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 (...

  12. Preliminary survey on tsetse flies and trypanosomosis at grazing ...

    African Journals Online (AJOL)

    Preliminary survey on tsetse flies and trypanosomosis were conducted between. July and August 2007 at grazing fields and villages in and around the Nech Sar national park, with the ultimate intention of forwarding baseline information on the extent of the problem and possible control strategies. . Entomological (Tsetse.

  13. Determining grazing capacity in Namibia with the aid of remote ...

    African Journals Online (AJOL)

    The Namibian rangelands consist of a mixture of herbaceous and woody components. The main source of income is from farming systems with grass production the predominant source of forage. For rangeland managers to utilise this source sustainably, the accurate determination of grazing capacity is vital since it allows ...

  14. Magnetic alignment in grazing and resting cattle and deer

    Czech Academy of Sciences Publication Activity Database

    Begall, S.; Červený, Jaroslav; Neef, J.; Burda, H.; Vojtěch, O.

    2008-01-01

    Roč. 105, č. 36 (2008), s. 13451-13455 ISSN 0027-8424 Institutional research plan: CEZ:AV0Z60930519 Keywords : grazing behavior * magnetic alignment * magnetoreception * resting behavior * spatial orientation Subject RIV: EH - Ecology, Behaviour Impact factor: 9.380, year: 2008

  15. Production response of lambs receiving creep feed while grazing ...

    African Journals Online (AJOL)

    The aim of the study was to determine the production responses of lambs receiving either creep feed or not while grazing two different pastures. The production of ewes within each treatment was also recorded. The study was conducted at both the Kromme Rhee and Langgewens Research Farms. At Kromme Rhee, sheep ...

  16. Effects of Grazing Abandoned Grassland on Herbage Production and Utilization, and Sheep Preference and Performance

    Directory of Open Access Journals (Sweden)

    Håvard Steinshamn

    2018-05-01

    Full Text Available Large areas of farmland are abandoned in Norway, which for various reasons are regarded as undesirable. Loss of farmland may have negative implications for biodiversity and ecosystem function and food production potential. The objectives of this study were to assess forage mass production and utilization, botanical composition, lamb performance, and grazing distribution pattern when reintroducing livestock grazing to an abandoned grassland. The study area was located in Central Norway, unmanaged for 12 years. Sheep grazed the area for 10 weeks in 2013 and 4 weeks in spring and autumn, respectively, in 2014 and 2015. During the summer of 2014 and 2015, the area was subjected to the following replicated treatments: (1 No grazing, (2 grazing with heifers, and (3 grazing with ewes and their offspring. The stocking rate was similar in the grazed treatments. Forage biomass production and animal intake were estimated using grazing exclosure cages and botanical composition by visual assessment. Effect on lamb performance was evaluated by live weight gain and slaughter traits in sheep subjected to three treatments: (1 Common farm procedure with summer range pasturing, (2 spring grazing period extended by 1 month on the abandoned grassland before summer range pasturing, and (3 spring and summer grazing on the abandoned grassland. Grazing distribution patterns were studied using GPS position collars on ewes. Total annual biomass production was on average 72% higher with summer grazing than without. Annual consumption and utilization was on average 218 g DM/m2 and 70% when summer grazed, and 25 g DM/m2 and 18% without grazing, respectively. Botanical composition did not differ between treatments. Live weight gain was higher in lambs subjected to an extended spring grazing period (255 g/d compared to common farm practice (228 g/d and spring and summer grazing on the abandoned grassland (203 g/d, and carcass value was 14% higher in lambs on extended spring

  17. Simulating grazing practices in a complete livestock system model: estimating soil carbon storage and greenhouse gas emissions in grazed versus un-grazed agroecosystems using the Manure-DNDC model

    Science.gov (United States)

    Campbell, E. E.; Dorich, C.; Contosta, A.; Varner, R. K.

    2017-12-01

    In livestock agroecosystems, the combined contributions of enteric fermentation, manure management, and livestock grazing and/or feed production play an important role in agroecosystem carbon (C) storage and GHG losses, with complete livestock system models acting as important tools to evaluate the full impacts of these complex systems. The Manure-DeNitrification-DeComposition (DNDC) model is one such example, simulating impacts on C and nitrogen cycling, estimating methane, carbon dioxide, nitrous oxide, and ammonium dynamics in fields, manure storage, and enteric emissions. This allows the evaluation of differences in GHG and soil C impacts between conventional and organic dairy production systems, which differ in their use of grazed pasture versus confined feeding operations. However, Manure-DNDC has received limited testing in representing variations in grazed pasture management (i.e. intensive rotational grazing versus standard grazing practices). Using a set of forage biomass, soil C, and GHG emissions data collected at four sites across New England, we parameterized and validated Manure-DNDC estimations of GHG emissions and soil C in grazed versus un-grazed systems. Soil observations from these sites showed little effect from grazing practices, but larger soil carbon differences between farms. This may be due to spatial variation in SOC, making it difficult to measure and model, or due to controls of edaphic properties that make management moot. However, to further address these questions, model development will be needed to improve Manure-DNDC simulation of rotational grazing, as high stocking density grazing over short periods resulted in forage not re-growing sufficiently within the model. Furthermore, model simulations did not account for variation in interactions between livestock and soil given variability in field microclimates, perhaps requiring simulations that divide a single field into multiple paddocks to move towards more accurate evaluation of

  18. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    Science.gov (United States)

    Schmidt, Niels M; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results High grazing intensity had a significant negative effect on Common shrew number compared to low grazing intensity and no grazing. Common shrew abundance was generally, but not significantly, higher on the low grazing intensity plots than on the ungrazed controls. No differences in body mass, sex ratio, or reproductive output between Common shrew individuals from the various grazing treatments were found. Conclusion No negative effects of low intensity grazing on Common shrew abundance were found compared to the ungrazed control. Low intensity grazing thus seems a suitable management regime for Common shrews, when grazing is needed as part of the meadow management scheme. High intensity grazing on the other hand is not a suitable management tool. PMID:19152713

  19. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus in two meadows in Denmark

    Directory of Open Access Journals (Sweden)

    Olsen Henrik

    2009-01-01

    Full Text Available Abstract Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results High grazing intensity had a significant negative effect on Common shrew number compared to low grazing intensity and no grazing. Common shrew abundance was generally, but not significantly, higher on the low grazing intensity plots than on the ungrazed controls. No differences in body mass, sex ratio, or reproductive output between Common shrew individuals from the various grazing treatments were found. Conclusion No negative effects of low intensity grazing on Common shrew abundance were found compared to the ungrazed control. Low intensity grazing thus seems a suitable management regime for Common shrews, when grazing is needed as part of the meadow management scheme. High intensity grazing on the other hand is not a suitable management tool.

  20. Effect of Vavilov–Cherenkov radiation cone transformation upon entry of a relativistic electron into a substance layer

    Energy Technology Data Exchange (ETDEWEB)

    Kishchin, I. A.; Kubankin, A. S., E-mail: kubankin@bsu.edu.ru; Nikulicheva, T. B.; Al-Omari; Sotnikov, A. V.; Starovoitov, A. S. [Belgorod National Research University (Russian Federation)

    2016-12-15

    Transformation of the Vavilov–Cherenkov radiation cone under grazing interaction of a relativistic electron with a layer of substance is theoretically studied. It is shown that this effect can occur when the electron enters the substance layer.

  1. The influence of grazing on surface climatological variables of tallgrass prairie. Final Technical Report

    International Nuclear Information System (INIS)

    Seastedt, T.R.; Dyer, M.I.; Turner, C.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

  2. Vegetation changes over 12 years in ungrazed and grazed Conservation Reserve Program Grasslands in the central and southern plains

    Science.gov (United States)

    Cade, Brian S.; Vandever, Mark W.; Allen, Arthur W.; Terrell, James W.

    2005-01-01

    years. The species of grass established in seeded grasslands can have a major influence on the potential quality of wildlife habitat where vegetation is maintained over a multi-year period. Different species of grass may have comparable abilities to alleviate soil erosion but furnish dissimilar qualities of wildlife habitat (fig. 1). For example, smooth brome, an introduced cool-season grass (grass species and scientific names are presented in table 1), is highly valued for its erosion control and forage attributes (Casler and Carlson, 1995). Switchgrass, a native warm-season grass, also is valued for its soil and water conservation qualities (Moser and Vogel, 1995) but provides greater benefits for some species of wildlife (Clubine, 1995). The quality of nesting and winter cover for ring-necked pheasants (Phasianus colchicus) furnished by smooth brome on northeastern Colorado CRP lands is inferior to that provided by the taller, more robust switchgrass (Allen, 1994). Characteristics of the agricultural landscape surrounding individual CRP fields also play a role in the wildlife habitat potential of CRP plantings (Weber and others, 2002; Nusser and others, 2004). of native and seeded grasslands change in response to the presence (and absence) of physical disturbances such as fire, grazing, tillage, and haying (Hobbs and Huenneke, 1992; Millenbah and others, 1996; Allen and others, 2001; Renfrew and Ribic, 2001; Swengel and Swengel, 2001). The perpetuation of diversity in species composition and vegetation structure following disturbance sustains desirable habitat for a variety of grassland-dependent wildlife (Hall and Willig, 1994; Barnes and others, 1995; King and Savidge, 1995; Granfors and others, 1996; Herkert and others, 1996; Kurzejeski, 1996; Patterson and Best, 1996; Klute and others, 1997). Undisturbed grasslands have lower grass and forb species diversity, greater amounts of dead plant material, decreased as well as seasonally delayed productivity, and

  3. Comparison of evapotranspiration components and water-use efficiency among different land use patterns of temperate steppe in the Northern China pastoral-farming ecotone.

    Science.gov (United States)

    Li, Yuzhe; Fan, Jiangwen; Hu, Zhongmin; Shao, Quanqin; Harris, Warwick

    2016-06-01

    Water-use efficiency (WUE), which links carbon and water cycles, is an important indicator of assessing the interactions between ecosystems and regional climate. Using chamber methods with and without plant removal treatments, we investigated WUE and evapotranspiration (ET) components in three ecosystems with different land-use types in Northern China pastoral-farming ecotone. In comparison, ET of the ecosystems with grazing exclusion and cultivating was 6.7 and 13.4 % higher than that of the ecosystem with free grazing. The difference in ET was primarily due to the different magnitudes of soil water evaporation (E) rather than canopy transpiration (T). Canopy WUE (WUEc, i.e., the ratio of gross primary productivity to T) at the grazing excluded and cultivated sites was 17 and 36 % higher than that at the grazing site. Ecosystem WUE (WUEnep, i.e., the ratio of net ecosystem productivity to ET) at the cultivated site was 34 and 28 % lower in comparison with grazed and grazing excluded stepped, respectively. The varied leaf area index (LAI) of different land uses was correlated with microclimate and ecosystem vapor/carbon exchange. The LAI changing with land uses should be the primary regulation of grassland WUE. These findings facilitate the mechanistic understanding of carbon-water relationships at canopy and ecosystem levels and projection of the effects of land-use change on regional climate and productivity.

  4. Changes in Carbon Emissions in Colombian Savannas Derived From Recent Land use and Land Cover Change

    Science.gov (United States)

    Etter, A.; Sarmiento, A.

    2007-12-01

    The global contribution of carbon emissions from land use dynamics and change to the global carbon (C) cycle is still uncertain, a major concern in global change modeling. Carbon emission from fires in the tropics is significant and represents 9% of the net primary production, and 50% of worldwide C emissions from fires are attributable to savanna fires. Such emissions may vary significantly due to differences in ecosystem types. Most savanna areas are devoted to grazing land uses making methane emissions also important in savanna ecosystems. Land use change driven by intensification of grazing and cropping has become a major factor affecting C emission dynamics from savanna regions. Colombia has some 17 MHa of mesic savannas which have been historically burned. Due to changes in market demands and improved accessibility during the last 20 years, important areas of savannas changed land use from predominantly extensive grazing to crops and intensive grazing systems. This research models and evaluates the impacts of such land use changes on the spatial and temporal burning patterns and C emissions in the Orinoco savannas of Colombia. We address the effects of land use change patterns using remote sensing data from MODIS and Landsat, ecosystem mapping products, and spatial GIS analysis. First we map the expansion of the agricultural frontier from the 1980s-2000s. We then model the changes in land use from the 1980s using a statistical modeling approach to analyze and quantify the impact of accessibility, ecosystem type and land tenure. We calculate the effects on C emissions from fire regimes and other sources of C based on patterns and extent of burned areas in the 2000s for different savanna ecosystem types and land uses. In the Llanos the fire regime exhibits a marked seasonal variability with most fire events occurring during the dry season between December-March. Our analysis shows that fire frequencies vary consistently between 0.6 and 2.8 fires.yr-1 per 2

  5. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    Science.gov (United States)

    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

  6. An X-ray grazing incidence phase multilayer grating

    CERN Document Server

    Chernov, V A; Mytnichenko, S V

    2001-01-01

    An X-ray grazing incidence phase multilayer grating, representing a thin grating placed on a multilayer mirror, is proposed. A high efficiency of grating diffraction can be obtained by the possibility of changing the phase shift of the wave diffracted from the multilayer under the Bragg and total external reflection conditions. A grazing incidence phase multilayer grating consisting of Pt grating stripes on a Ni/C multilayer and optimized for the hard X-ray range was fabricated. Its diffraction properties were studied at photon energies of 7 and 8 keV. The obtained maximum value of the diffraction efficiency of the +1 grating order was 9% at 7 keV and 6.5% at 8 keV. The data obtained are in a rather good accordance with the theory.

  7. Invariant polygons in systems with grazing-sliding.

    Science.gov (United States)

    Szalai, R; Osinga, H M

    2008-06-01

    The paper investigates generic three-dimensional nonsmooth systems with a periodic orbit near grazing-sliding. We assume that the periodic orbit is unstable with complex multipliers so that two dominant frequencies are present in the system. Because grazing-sliding induces a dimension loss and the instability drives every trajectory into sliding, the system has an attractor that consists of forward sliding orbits. We analyze this attractor in a suitably chosen Poincare section using a three-parameter generalized map that can be viewed as a normal form. We show that in this normal form the attractor must be contained in a finite number of lines that intersect in the vertices of a polygon. However the attractor is typically larger than the associated polygon. We classify the number of lines involved in forming the attractor as a function of the parameters. Furthermore, for fixed values of parameters we investigate the one-dimensional dynamics on the attractor.

  8. Adjustable Grazing-Incidence X-Ray Optics

    Science.gov (United States)

    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.

  9. Active Full-Shell Grazing-Incidence Optics

    Science.gov (United States)

    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.

  10. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season.

    Science.gov (United States)

    Murillo, M; Herrera, E; Ruiz, O; Reyes, O; Carrete, F O; Gutierrez, H

    2016-05-01

    Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with

  11. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

    Directory of Open Access Journals (Sweden)

    M. Murillo

    2016-05-01

    Full Text Available Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW] were distributed randomly into 3 groups (each of 40 steers, which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May. Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size. Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G, urea-nitrogen (UN and non-esterified fatty acids. Final BW, average daily gain (ADG and supplement conversion (CDDGS-C increased with increasing levels of CDDGS supplementation (p<0.05.The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05. In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW, and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI, apparent digestibility of dry matter (ADDM, crude protein (ADCP and neutral detergent fiber (ADNDF increased with increasing levels of CDDGS supplementation (p<0.05. The ruminal degradation rates of CP (kdCP, NDF (kdNDF and passage rate (kp also increased with increasing levels of CDDGS supplementation (p<0.05. Ruminal ammonia nitrogen (NH3-N and propionate concentrations also increased with

  12. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

    Science.gov (United States)

    Murillo, M.; Herrera, E.; Ruiz, O.; Reyes, O.; Carrete, F. O.; Gutierrez, H.

    2016-01-01

    Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with

  13. Bite frequency measured by head pitch movements in grazing experiment

    DEFF Research Database (Denmark)

    Oudshoorn, Frank W.; S. Nadimi, Esmaeil; Jørgensen, Rasmus Nyholm

    2010-01-01

    . ECPLF      2007 Skiathos, Greece. p 111-116 Pulido, R.G. & Leaver, J.D., 2001. Quantifying the influence of sward height, concentrate level and initial      milk yield on the milk production and grazing behaviour of continuously stocked dairy cows. Grass      and Forage Science 56, 57-67.    ...

  14. Grazing and metabolism of Euphausia pacifica in the Yellow Sea.

    Directory of Open Access Journals (Sweden)

    Zhencheng Tao

    Full Text Available 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.

  15. The ability of winter grazing to reduce wildfire size, intensity ...

    Science.gov (United States)

    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

  16. Federal Lands

    Data.gov (United States)

    Department of Homeland Security — This map layer consists of federally owned or administered lands of theUnited States, Puerto Rico, and the U.S. Virgin Islands. Only areas of 640 acres or more are...

  17. Land Research

    Science.gov (United States)

    EPA is working to develop methods and guidance to manage and clean up contaminated land, groundwater and nutrient pollution as well as develop innovative approaches to managing materials and waste including energy recovery.

  18. Introducing cattle grazing to a noxious weed-dominated rangeland shifts plant communities

    Directory of Open Access Journals (Sweden)

    Josh S. Davy

    2015-10-01

    Full Text Available Invasive weed species in California's rangelands can reduce herbaceous diversity, forage quality and wildlife habitat. Small-scale studies (5 acres or fewer have shown reductions of medusahead and yellow starthistle using prescribed grazing on rangelands, but little is published on the effects of pasture-scale (greater than 80 acres prescribed grazing on weed control and plant community responses. We report the results of a 6-year collaborative study of manager-applied prescribed grazing implemented on rangeland that had not been grazed for 4 years. Grazing reduced medusahead but did not alter yellow starthistle cover. Medusahead reductions were only seen in years that did not have significant late spring rainfall, suggesting that it is able to recover from heavy grazing if soil moisture is present. Later season grazing appears to have the potential to suppress medusahead in all years. In practice, however, such grazing is constrained by livestock drinking water availability and forage quality, which were limited even in years with late spring rainfall. Thus, we expect that grazing treatments under real-world constraints would reduce medusahead only in years with little late spring rainfall. After 10 years of grazing exclusion, the ungrazed plant communities began to shift, replacing medusahead with species that have little value, such as ripgut and red brome.

  19. Zooplankton grazing in a eutrophic lake: implications of diel vertical migration

    International Nuclear Information System (INIS)

    Lampert, W.; Taylor, B.E.

    1985-01-01

    During summer and fall, depth profiles of zooplankton community grazing were determined in situ during day and night in the Schoehsee, a small eutrophic lake. Labeled algae of two different sizes were mixed with the natural suspension of phytoplankton in a grazing chamber. A small blue-green alga (Synechococcus, 1 μm) was labeled with 32 P; a larger green alga (Scenedesmus, 4-15 μm) was labeled with 14 C. During summer, grazing in the upper 5 m was negligible during day but strong at night. Hence, algae grow relatively unimpeded by grazing during daytime but are harvested at night. Vertical and diel differences in grazing rates disappeared when the vertical migration ceased in fall. Selectivity of grazing was controlled by the zooplankton species composition. Eudiaptomus showed a strong preference for Scenedesmus. Daphnia showed a slight preference for Scenedesmus, but Ceriodaphnia preferred Synechococcus. Cyclopoid copepodites did not ingest the small blue-green. Because Daphnia and Eudiaptomus were dominant, grazing rates on larger cells were usually higher than grazing rates on the small cells. Negative electivity indices for scenedesmus occurred only when the biomass of large crustaceans was extremely low (near the surface, during day). Zooplankton biomass was the main factor controlling both vertical and seasonal variations in grazing. Highest grazing rates (65%/d) were measured during fall when zooplankton abundance was high. Because differential losses can produce substantial errors in the results, it was necessary to process the samples on the boat immediately after collection, without preservation

  20. Dynamics of forage accumulation in Elephant grass subjected to rotational grazing intensities

    Directory of Open Access Journals (Sweden)

    Braulio Maia de Lana Sousa

    2013-09-01

    Full Text Available We assessed the accumulation dynamics of forage and its components in Elephant grass cv. Napier (Pennisetum purpureum Schum. that were subjected to three post-grazing height treatments (30, 50, and 70 cm from February through May 2009 (experiment one and December 2009 through May 2010 (experiment two. In experiment one, the grazing events started when the light interception by the canopy reached 95%. The same was adopted for experiment two, except for the first grazing event, which was based on the height of the apical meristems of basal tillers. The experimental design for both experiments was a randomized complete block with three replications. The pastures that were managed at a post-grazing height of 30 cm exhibited lower rates of leaf and stem growth, total growth and forage accumulation than those that were managed at 50 or 70 cm, indicating that post-grazing height affects Elephant grass. The pastures that were managed at 50 cm exhibited relatively stable accumulation rates and less stem accumulation. Pastures managed at 70 cm of pos-grazing height presented more leaf and stem accumulation. Most apical meristems of Elephant grass should be removed in the first grazing when they reach the post-grazing target height of 50 cm. The elevation in the residual post-grazing height, especially in the summer, raises the regrowth vigor in the Elephant grass cv. Napier pasture. The post-grazing height of 30 cm reduces the growth of the Elephant grass cv. Napier.

  1. Land uses, fire, and invasion: Exotic annual Bromus and human dimensions [Chapter 11

    Science.gov (United States)

    David A. Pyke; Jeanne C. Chambers; Jeffrey L. Beck; Matthew L. Brooks; Brian A. Mealor

    2016-01-01

    Human land uses are the primary cause of the introduction and spread of exotic annual Bromus species. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors...

  2. Projecting land use changes in the Neotropics: the geography of pasture expansion into forest

    NARCIS (Netherlands)

    Wassenaar, T.; Gerber, P.; Verburg, P.H.; Rosales, M.; Ibrahim, M.; Steinfeld, H.

    2007-01-01

    In tropical Latin America, pasture land for extensive grazing continues to expand, mostly at the expense of forest cover. Until now, scientists and policy makers tackling this issue had no geographically exhaustive information at the continental level about the spatial dynamics of this process. On

  3. RANGE RAM: a long-term planning method for managing grazing lands

    Science.gov (United States)

    Henricus C. Jansen

    1976-01-01

    Range RAM (Resource Allocation Method) is a computerized planning method designed to assist range managers in developing and selecting alternatives in spatial and temporal allocation of resources. The technique is applicable at the frest or district management levels, or their equivalents. Range RAM can help formulate plans that maximize the production of range outputs...

  4. Grazing exit versus grazing incidence geometry for x-ray absorption near edge structure analysis of arsenic traces

    International Nuclear Information System (INIS)

    Meirer, F.; Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

    2009-01-01

    In the presented study the grazing exit x-ray fluorescence was tested for its applicability to x-ray absorption near edge structure analysis of arsenic in droplet samples. The experimental results have been compared to the findings of former analyses of the same samples using a grazing incidence (GI) setup to compare the performance of both geometries. Furthermore, the investigations were accomplished to gain a better understanding of the so called self-absorption effect, which was observed and investigated in previous studies using a GI geometry. It was suggested that a normal incidence-grazing-exit geometry would not suffer from self-absorption effects in x-ray absorption fine structure (XAFS) analysis due to the minimized path length of the incident beam through the sample. The results proved this assumption and in turn confirmed the occurrence of the self-absorption effect for GI geometry. Due to its lower sensitivity it is difficult to apply the GE geometry to XAFS analysis of trace amounts (few nanograms) of samples but the technique is well suited for the analysis of small amounts of concentrated samples

  5. The relationships between biodiversity and ecosystem services and the effects of grazing cessation in semi-natural grasslands

    Directory of Open Access Journals (Sweden)

    S. Wehn

    2018-04-01

    Full Text Available Land use change can affect biodiversity, and this has an impact on ecosystem services (ESs, but the relationships between biodiversity and ESs are complex and poorly understood. Biodiversity is declining due to the abandonment of extensively grazed semi-natural grasslands.We therefore aim to explore relationships between biodiversity and ESs provided by extensively managed semi-natural grasslands. Focusing on vascular plant species richness, as well as the ESs fodder quantity, quality, and stability, allergy control, climate regulation, nutrient cycling, pollination, and aesthetic appreciation, we carried out botanical field surveys of 28 paired extensively grazed and abandoned semi-natural grassland plots, with four subplots of 4 m2 in each plot. The management of the semi-natural grasslands is and has been at low intensity. We calculated the influence of abandonment on the ES indicators, measured the correlation between the biodiversity measure of vascular plant species richness and ES indicators, and finally determined how the relationships between plant species richness and the ES indicators were affected by the cessation of the extensive management.ES indicators are often, but not always, positively correlated with species richness. Cessation of extensive grazing has both negative and positive effects on ES indicators but the relationships between species richness and ES indicators are often different in extensively managed and abandoned semi-natural grasslands. The relationships between species richness and ES indicators are less pronounced in the extensively managed semi-natural grassland than for the abandoned. One possible reason for this outcome is high functional redundancy in the extensively managed semi-natural grasslands.

  6. Transitions and coexistence along a grazing gradient in the Eurasian steppe

    Science.gov (United States)

    Ren, Haiyan; Taube, Friedelm; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

    2017-04-01

    Ecological resilience theory has often been applied to explain species coexistence and range condition assessment of various community states and to explicate the dynamics of ecosystems. Grazing is a primary disturbance that can alter rangeland resilience by causing hard-to-reverse transitions in grasslands. Yet, how grazing affects the coexistence of plant functional group (PFG) and transition remains unclear. We conducted a six-year grazing experiment in a typical steppe of Inner Mongolia, using seven grazing intensities (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ hectare) and two grazing systems (i.e. a continuous annual grazing as in the traditional grazing system, and a mixed grazing system combining grazing and haymaking), to examine grazing effects on plant functional group shifts and species coexistence in the semi-arid grassland system. Our results indicate that the relative richness of dominant bunchgrasses and forbs had a compensatory coexistence at all grazing intensities, and the richness of rhizomatous grasses fluctuated but was persistent. The relative productivity of dominant bunchgrasses and rhizomatous grasses had compensatory interactions with grazing intensity and grazing system. Dominant bunchgrasses and rhizomatous grasses resist grazing effects by using their dominant species functional traits: high specific leaf area and low leaf nitrogen content. Our results suggest that: 1. Stabilizing mechanisms beyond grazing management are more important in determining plant functional group coexistence and ecological resilience. 2. Plant functional group composition is more important in influencing ecosystem functioning than diversity. 3. Ecosystem resilience at a given level is related to the biomass of dominant PFG, which is determined by a balanced shift between dominant species biomass. The relatively even ecosystem resilience along the grazing gradient is attributed to the compensatory interactions of dominant species in their biomass variations

  7. Impacts of out-migration on land management in mountain areas

    OpenAIRE

    Schwilch, Gudrun; Jaquet, Stéphanie; Liniger, Hanspeter; Sudmeier-Rieux, K.; Penna, I.; Jaboyedoff, M.; Kaenzig, R.

    2013-01-01

    INTRODUCTION Out-migration from mountain areas is leaving behind half families and elderly to deal with managing the land alongside daily life challenges. A potential reduction of labour force as well as expertise on cropping practices, maintenance of terraces and irrigation canals, slope stabilization, grazing, forest and other land management practices are further challenged by changing climate conditions and increased environmental threats. An understanding of the resilience of managed...

  8. The influence of grazing intensity on soil properties and degradation processes in Mediterranean rangelands (Extremadura, SW Spain)

    Science.gov (United States)

    Pulido-Fernández, Manuel; Schnabel, Susanne; Francisco Lavado-Contador, Joaquín

    2014-05-01

    Rangelands cover vast extensions of land in Spain (>90,000 km2), where a total amount of 13 millions of domestic animals graze extensively their pastures. By clear-cutting shrubs, removing selected trees and by cultivation, these rangelands were created from former Mediterranean oak forests, mainly composed by holm oak and cork oak (Quercus ilex rotundifolia and Q. suber) as tree species, Nowadays this land system is exploited economically in large farms (>100 ha), most of them held on private ownership (80% of total) and dedicated to extensive ranching. Overgrazing is common and the excessive stocking rates may deteriorate soil quality, causing economic losses and environmental damage. Many studies have been developed on the effects of livestock grazing over soil properties and degradation processes, most of them by only comparing extreme cases (e.g. ungrazed vs. grazed or overgrazed areas). The main goal of this study is to contribute to the understanding on how animal grazing affects soil properties and degradation processes. The study is particularly focused on soil compaction and sheet erosion as related to the reduction of vegetation cover by defoliation. Soil properties were analysed from 119 environmental units selected from 56 farms distributed throughout the region of Extremadura (SW Spain). The units are representative of different rangeland types, i.e. scrublands of Retama sphaerocarpa, dehesas (wooded rangelands) and treeless grasslands. Soil surface cover was determined along transects in September 2010 (antecedent rainfall: 413-923 mm) considering the following classes: bare ground, grasses, mosses, litter, stones (<2 mm) and rock outcrops. Farmer interviews were also conducted in order to quantify stocking rates and to assess land management in 12 out of 56 farms. In the farms where transects and farmer interviews could not be carried out, bare soil surface and livestock densities were estimated. Bare soil surface was determined by classifying

  9. Land use

    International Nuclear Information System (INIS)

    Rickard, W.H.; Rogers, L.E.

    1977-01-01

    Justification for large land holdings at the Hanford Reservation has centered around a need for security and also as a buffer zone in the event of accidents. In recent years the importance of these large land holdings have become nationally recognized as highly desirable locations for ecological research concerning the function and structure of terrestrial ecosystems and as places to investigate the response of terrestrial ecosystems to long-term man-imposed environmental stresses. Carefully selected and protected land areas exist on the 110 square mile Arid Land Ecology Reserve (ALE) at Hanford. The projects described here provide supporting research for several applied projects that deal with environmental impact and land restoration. Information gained from this research has wide use and applicability to all kinds of energy technologies centered in the semi-arid shrub-steppe region of the northwestern United States. Ecological information reported includes: biotic characterization, including description of major habitats and endangered or threatened species; performances of native plant species, including determination of growth habits, nutrient requirements, and productivity; and, mineral cycling, including particularly the estimation of availability and behavior of airborne deposits to green plants

  10. Density and success of bird nests relative to grazing on western Montana grasslands

    Science.gov (United States)

    Fondell, Thomas F.; Ball, I.J.

    2004-01-01

    Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid

  11. Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

    Directory of Open Access Journals (Sweden)

    Péter Török

    Full Text Available Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i How does cattle grazing affect species composition and diversity of the grasslands? (ii What are the effects of grazing on short-lived and perennial noxious species? (iii Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands was sampled from 2006-2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable

  12. Reorienting land degradation towards sustainable land management: linking sustainable livelihoods with ecosystem services in rangeland systems.

    Science.gov (United States)

    Reed, M S; Stringer, L C; Dougill, A J; Perkins, J S; Atlhopheng, J R; Mulale, K; Favretto, N

    2015-03-15

    This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded rangelands towards more sustainable land management. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Estimating the potential intensification of global grazing systems based on climate adjusted yield gap analysis

    Science.gov (United States)

    Sheehan, J. J.

    2016-12-01

    We report here a first-of-its-kind analysis of the potential for intensification of global grazing systems. Intensification is calculated using the statistical yield gap methodology developed previously by others (Mueller et al 2012 and Licker et al 2010) for global crop systems. Yield gaps are estimated by binning global pasture land area into 100 equal area sized bins of similar climate (defined by ranges of rainfall and growing degree days). Within each bin, grid cells of pastureland are ranked from lowest to highest productivity. The global intensification potential is defined as the sum of global production across all bins at a given percentile ranking (e.g. performance at the 90th percentile) divided by the total current global production. The previous yield gap studies focused on crop systems because productivity data on these systems is readily available. Nevertheless, global crop land represents only one-third of total global agricultural land, while pasture systems account for the remaining two-thirds. Thus, it is critical to conduct the same kind of analysis on what is the largest human use of land on the planet—pasture systems. In 2013, Herrero et al announced the completion of a geospatial data set that augmented the animal census data with data and modeling about production systems and overall food productivity (Herrero et al, PNAS 2013). With this data set, it is now possible to apply yield gap analysis to global pasture systems. We used the Herrero et al data set to evaluate yield gaps for meat and milk production from pasture based systems for cattle, sheep and goats. The figure included with this abstract shows the intensification potential for kcal per hectare per year of meat and milk from global cattle, sheep and goats as a function of increasing levels of performance. Performance is measured as the productivity achieved at a given ranked percentile within each bin.We find that if all pasture land were raised to their 90th percentile of

  14. Temporal profiles of vegetation indices for characterizing grazing intensity on natural grasslands in Pampa biome

    Directory of Open Access Journals (Sweden)

    Amanda Heemann Junges

    2016-08-01

    Full Text Available ABSTRACT The Pampa biome is an important ecosystem in Brazil that is highly relevant to livestock production. The objective of this study was to analyze the potential use of vegetation indices to discriminate grazing intensities on natural grasslands in the Pampa biome. Moderate Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI and Enhanced Vegetation Index (EVI images from Jan to Dec, 2000 to 2013 series, were analyzed for natural grassland experimental units managed under high (forage allowance of 5 ± 2 % live weight – LW, moderate (13 ± 5 % LW and low grazing intensity (19 ± 7 % LW. Regardless of intensity, the temporal profiles showed lower NDVI and EVI during winter, increased values in spring because of summer species regrowth, slightly decreased values in summer, especially in years when there is a water deficit, and increased values in the fall associated with the beginning of winter forage development. The average temporal profiles of moderate grazing intensity exhibited greater vegetation index values compared with low and high grazing intensities. The temporal profiles of less vegetation index were associated with lower green biomass accumulation caused by the negative impact of stocking rates on the leaf area index under high grazing intensity and a floristic composition with a predominance of tussocks under low grazing intensity. Vegetation indices can be used for distinguishing moderate grazing intensity from low and high intensities. The average EVI values can discriminate moderate grazing intensity during any season, and the NDVI values can discriminate moderate grazing intensity during spring and winter.

  15. Grazing reduces soil greenhouse gas fluxes in global grasslands: a meta-analysis

    Science.gov (United States)

    Tang, Shiming; Tian, Dashuan; Niu, Shuli

    2017-04-01

    Grazing causes a worldwide degradation in grassland and likely alters soil greenhouse gas fluxes (GHGs). However, the general patterns of grazing-induced changes in grassland soil GHGs and the underlying mechanisms remain unclear. Thus, we synthesized 63 independent experiments in global grasslands that examined grazing impacts on soil GHGs (CO2, CH4 and N2O). We found that grazing with light or moderate intensity did not significantly influence soil GHGs, but consistently depressed them under heavy grazing, reducing CO2 emission by 10.55%, CH4 uptake by 19.24% and N2O emission by 28.04%. The reduction in soil CO2 was mainly due to decreased activity in roots and microbes (soil respiration per unit root and microbial biomass), which was suppressed by less water availability due to higher soil temperature induced by lower community cover under heavy grazing. N2O emission decreased with grazing-caused decline in soil total N. The inhibitory effect on methanotroph activities by water stress is responsible for the decreased CH4 uptake. Furthermore, grazing duration and precipitation also influenced the direction and magnitude of responses in GHGs fluxes. Overall, our results indicate that the reduction in soil CO2 and N2O emission under heavy grazing is partially compensated by the decrease in CH4 uptake, which is mainly regulated by variations in soil moisture.

  16. Living Lands

    DEFF Research Database (Denmark)

    Christensen, Suna Møller

    2015-01-01

    , hunters attended to questions like safe-journeying on ice or the role of natural surroundings in children’s education, in ways revealing a relational perception of ‘nature’ and dissolving culture-nature dualisms. Hunters’ experiences in living the land afforded children a dwelling position from which...... to grow with the features of the land. Framed this way, ‘nature’ was regarded as part of the social world. I suggest that learning among Arctic hunters is social and twofold. First, we can learn how human-environment relations influence individual life trajectories. Secondly, ‘nature’ as part...

  17. Optimizing Excited-State Electronic-Structure Codes for Intel Knights Landing: A Case Study on the BerkeleyGW Software

    Energy Technology Data Exchange (ETDEWEB)

    Deslippe, Jack; da Jornada, Felipe H.; Vigil-Fowler, Derek; Barnes, Taylor; Wichmann, Nathan; Raman, Karthik; Sasanka, Ruchira; Louie, Steven G.

    2016-10-06

    We profile and optimize calculations performed with the BerkeleyGW code on the Xeon-Phi architecture. BerkeleyGW depends both on hand-tuned critical kernels as well as on BLAS and FFT libraries. We describe the optimization process and performance improvements achieved. We discuss a layered parallelization strategy to take advantage of vector, thread and node-level parallelism. We discuss locality changes (including the consequence of the lack of L3 cache) and effective use of the on-package high-bandwidth memory. We show preliminary results on Knights-Landing including a roofline study of code performance before and after a number of optimizations. We find that the GW method is particularly well-suited for many-core architectures due to the ability to exploit a large amount of parallelism over plane-wave components, band-pairs, and frequencies.

  18. Using digital photography to examine grazing in montane meadows

    Science.gov (United States)

    McIlroy, Susan K.; Allen-Diaz, Barbara H.; Berg, Alexander C.

    2011-01-01

    Cattle (Bos taurus) numbers on national forests are allocated based on allotment grazing capacity, but spatial patterns of timing and density at smaller scales are difficult to assess. However, it is often in meadows or riparian areas that grazing may affect hydrology, biodiversity, and other important ecosystem characteristics. To explore real-time animal presence in montane meadows we distributed 18 digital cameras across nine sites in the Sierra National Forest, California. Our objectives were to document seasonal and diurnal presence of both cattle and mule deer (Odocoileus hemionus), identify the effects of three fencing treatments on animal distribution, and test digital photography as a tool for documenting cattle presence. We recorded 409 399 images during daylight hours for two grazing seasons, and we identified 5 084 and 24 482 cattle "marks" (instances of animal occurrence) in 2006 and 2007, respectively. Deer presence was much lower, with 331 marks in 2006 and 598 in 2007. Morning cattle presence was highest before 0800 hours both years (13.7% and 15.4% of total marks for 2006 and 2007, respectively). Marks decreased until 1100 hours and then increased around 1400 hours and remained relatively stable until 1900 hours. Marks then rose precipitously, with >20% of total marks recorded after 1900 hours both years. Deer presence was less than 10% per hour until 1800 hours, when >20% of total marks were recorded after this time both years. Among treatments, cattle marks were highest outside fences at partially fenced meadows, and deer were highest within completely fenced meadows. Our experience suggests that cameras are not viable tools for meadow monitoring due to variation captured within meadows and the time and effort involved in image processing and review.

  19. Annual methane budgets of sheep grazing systems were regulated by grazing intensities in the temperate continental steppe: A two-year case study

    Science.gov (United States)

    Ma, Lei; Zhong, Mengying; Zhu, Yuhao; Yang, Helong; Johnson, Douglas A.; Rong, Yuping

    2018-02-01

    Methane (CH4) emission from animal husbandry accounts for a large percentage of anthropogenic contributions to CH4 emissions. Fully understanding of grazing management effects on the CH4 budget is essential for mitigating CH4 emissions in the temperate grazing steppe systems. Annual CH4 budgets for the sheep grazed steppes at various grazing intensities, un-grazing (UG, 0 sheep ha-1year-1), defer grazing (DG, 1.0 sheep ha-1 year-1), moderate grazing (MG, 1.43 sheep ha-1year-1), and heavy grazing (HG, 2.43 sheep ha-1year-1) were assessed across 2012-2014 in the agro-pastoral region of northern China. Annual soil CH4 uptake averaged across 2012-2014 were 1.1 ± 0.1, 2.4 ± 0.2, 2.2 ± 0.2, and 1.3 ± 0.1 kg CH4-C ha-1 for UG, DG (only 2013-2014), MG and HG sites. Non-growing season CH4 uptake comprised 50.0 ± 4.3% of annual CH4 uptake in 2012-2013 and 37.7 ± 2.0% in 2013-2014. DG and MG significantly promoted annual soil CH4 uptake (P 0.05). Bell-shaped relationship was presented between stocking rates and soil CH4 uptake (r2 = 0.59, P budgets for the grazed grasslands were -1.1 ± 0.1, 5.7 ± 0.6, 11.5 ± 1.5 and 15.5 ± 1.3 kg CH4-C ha-1 year-1 in UG, DG (only 2013-2014), MG and HG across 2012-2014. Soil CH4 uptake could offset 29.7 ± 5.6, 15.9 ± 4.3 and 6.8 ± 1.0% of total annual CH4 emissions from sheep, sheepfold and faeces in DG, MG, and HG. All grazed steppes are sources for atmospheric CH4 and the magnitude is regulated by grazing intensities. Sheep CH4 emissions for 1-g liveweight gain were 0.21, 0.32 and 0.37 g CH4-C in DG, MG and HG, respectively. DG is the recommended grazing management in this region to achieve greater herbage mass, higher sheep performance and lower CH4 emissions simultaneously.

  20. Review of grazing studies on plutonium-contaminated rangelands

    International Nuclear Information System (INIS)

    Smith, D.D.

    1977-01-01

    Literature is cited that has provided data on tissue actinide concentrations in grazing animals when the actinide dosages resulted from artificial administration or from periodic exposure. Only one long-term study is known where a reproducing beef herd was restricted to a plutonium-contaminated environment. Highlights of this study that are reviewed and discussed include: relationship of ingesta concentrations to food habits; tissue concentration related to length of exposure and level of exposure; and the concentration range in various tissues. Emphasis is given to the gonadal concentration which is approximately 25 times that of muscle and blood. Future study plans are also discussed

  1. Vegetation and Grazing in the St. Katherine Protectorate, South ...

    African Journals Online (AJOL)

    5. Grazing pressure. 1. 2. 3. 4. 5. P lant health. Unk . La bita e. Le gu m ino s a e. Co m p o sita e. A m ara nthac ea e. B ora gin ace ae. C h en opo dia c e ae. E u ph orb iac ea e. S cro ph ula ria cea e. A sc lep id ac e ae. C a ry o phy lla cea e. R ese dace ae. C a pp arace ae. Cuc urb ita cea e. Cruc ife rae. Gram inae. U m be.

  2. An Evaluation of Grazing-Incidence Optics for Neutron Imaging

    Science.gov (United States)

    Gubarev, M. V.

    2007-01-01

    The refractive index for most materials is slightly less than unity, which opens an opportunity to develop the grazing incidence neutron imaging optics. The ideal material for the optics would be natural nickel and its isotopes. Marshall Space Flight Center (MSFC) has active development program on the nickel replicated optics for use in x-ray astronomy. Brief status report on the program is presented. The results of the neutron focusing optic test carried by the MSFC team at National Institute of Standards and Technology (NIST) are also presented. Possible applications of the optics are briefly discussed.

  3. Optical design of grazing incidence toroidal grating monochromator

    International Nuclear Information System (INIS)

    Pouey, M.; Howells, M.R.; Takacs, P.Z.

    1982-01-01

    Design rules using geometrical optics and physical optics associated with the phase balancing method are discussed for stigmatic toroidal grazing incidence monochromators. To determine the optical performance of devices involving mirrirs and/or gratings, ray tracing programs using exact geometry are quite widely used. It is then desirable to have some way to infer the practical performance of an instrument from a spot diagram created by tracing a limited number of rays. We propose a first approach to this problem involving an estimation of the geometrical intensity distribution in the image plane and the corresponding line spread function. (orig.)

  4. Scenario-Led Habitat Modelling of Land Use Change Impacts on Key Species.

    Directory of Open Access Journals (Sweden)

    Matthew Geary

    Full Text Available Accurate predictions of the impacts of future land use change on species of conservation concern can help to inform policy-makers and improve conservation measures. If predictions are spatially explicit, predicted consequences of likely land use changes could be accessible to land managers at a scale relevant to their working landscape. We introduce a method, based on open source software, which integrates habitat suitability modelling with scenario-building, and illustrate its use by investigating the effects of alternative land use change scenarios on landscape suitability for black grouse Tetrao tetrix. Expert opinion was used to construct five near-future (twenty years scenarios for the 800 km2 study site in upland Scotland. For each scenario, the cover of different land use types was altered by 5-30% from 20 random starting locations and changes in habitat suitability assessed by projecting a MaxEnt suitability model onto each simulated landscape. A scenario converting grazed land to moorland and open forestry was the most beneficial for black grouse, and 'increased grazing' (the opposite conversion the most detrimental. Positioning of new landscape blocks was shown to be important in some situations. Increasing the area of open-canopy forestry caused a proportional decrease in suitability, but suitability gains for the 'reduced grazing' scenario were nonlinear. 'Scenario-led' landscape simulation models can be applied in assessments of the impacts of land use change both on individual species and also on diversity and community measures, or ecosystem services. A next step would be to include landscape configuration more explicitly in the simulation models, both to make them more realistic, and to examine the effects of habitat placement more thoroughly. In this example, the recommended policy would be incentives on grazing reduction to benefit black grouse.

  5. Genetic strain and diet effects on grazing behavior, pasture intake, and milk production.

    Science.gov (United States)

    Sheahan, A J; Kolver, E S; Roche, J R

    2011-07-01

    Understanding how dairy cows adjust their grazing behavior in response to feed supplements is important for the development of management strategies that optimize profit from supplementation. New Zealand Holstein-Friesian (HF) cows have been selected for milk production on a predominantly pasture-based diet; in comparison, HF cows of North American (NA) ancestry have been selected almost exclusively for milk yield and fed diets high in nonfiber carbohydrates (NFC). We hypothesized, therefore, that supplementation would have differing effects on grazing behavior, pasture dry matter intake (DMI), and milk production in these genetic strains at peak, mid, and late lactation. A study was conducted over 2 consecutive lactations, with NA and NZ cows randomly allocated at calving to 0, 3, or 6 kg of dry matter/day concentrate plus unrestricted access to pasture. Pasture DMI, milk production, and grazing behavior were recorded at peak, mid, and late lactation. Concentrates were fed in equal amounts at morning and afternoon milking. The NA cows produced more milk and milk components, and had a greater pasture DMI, despite spending less time grazing. Declines in time spent grazing and pasture DMI were associated with increasing concentrate DMI. Grazing behavior following morning supplementation was different from that recorded following afternoon supplementation. Grazing ceased following morning supplementation before rumen fill could be a limiting factor, and the length of the grazing interval was inversely proportional to the amount of concentrate offered; these results suggest that physiological rather than physical stimuli were responsible for grazing cessation. The decrease in time spent grazing with increasing concentrate DMI is consistent with changes in neuroendocrine factors secreted in response to the presence of food in the digestive tract or with circulating products of digestion. After afternoon supplementation, sunset signaled the end of grazing irrespective of

  6. The impact of cattle and goats grazing on vegetation in oak stands of varying coppicing age

    Science.gov (United States)

    Papachristou, Thomas G.; Platis, Panayiotis D.

    2011-01-01

    The effects of cattle and goats grazing on oak shoot growth and herbaceous vegetation in three oak forest stands with different coppicing age (1, 4 and 7 yrs after the clear cutting) were investigated. In April 1997, an experimental area was chosen with three forest stands, which were clear cut in 1996 (CL1996), 1993 (CL1993), and 1990 (CL1990). All stands were grazed by cattle and goats after they were clear cut. In each forest stand, five 10 m × 10 m paired plots were located, which represented grazed and protected patches. Herbage biomass within protected and grazed plots was measured four times each year (spring: May-June, summer: July-August, autumn: September-October, and winter: November-December). Behavioural observations on grazing animals were conducted in the same periods. In both protected and open plots the height and basal diameter of all oak shoots on 5 preselected stumps were measured at the end of five growing periods from 1997 to 2001. All forest stands carried a similar amount of available herbage (averaged over forest stands and growing season, 2614 kg/ha). Grazing animals removed on average 1057 kg/ha throughout the growing period. Cattle mainly consumed herbage (97% of bites) while goats consumed a mixture of oak browse (41% bites), herbaceous species (34% bites), and other woody species browse (25% bites). The height, diameter and volume of oak shoots were affected by grazing. The three forest stands had similar shoot heights in the protected plots in 2001 after 5 years of grazing protection. The volume of oak shoots of the grazed plots were 146.7 cm3 for CL1996, 232.9 cm3 for CL1993, and 239.1 cm3 for CL1990 in 2001 (i.e. 5, 8, and 11 years grazing after the clear cuttings, respectively). The protected plots carried greater volumes of oak shoots, CL1996: 496.0 cm3 (few months grazing before protection), CL1993: 690.0 cm3 (4 years grazing before protection), and CL1990: 344.0 cm3 (7 years grazing before protection). In conclusion, almost

  7. Electronic structure and Landé g-factor of a quantum ring in the presence of spin-orbit coupling: Temperature and Zeeman effect

    Science.gov (United States)

    Zamani, A.; Setareh, F.; Azargoshasb, T.; Niknam, E.

    2017-10-01

    A wide variety of semiconductor nanostructures have been fabricated experimentally and both theoretical and experimental investigations of their features imply the great role they have in new generation technological devices. However, mathematical modeling provide a powerful means due to definitive goal of predicting the features and understanding of such structures behavior under different circumstances. Therefore, effective Hamiltonian for an electron in a quantum ring with axial symmetry in the presence of both Rashba and Dresselhaus spin-orbit interactions (SOI) is derived. Here we report our study of the electronic structure and electron g-factor in the presence of spin-orbit (SO) couplings under the influence of external magnetic field at finite temperature. This investigation shows that, when Rashba and Dresselhaus couplings are simultaneously present, the degeneracy is removed and energy levels split into two branches. Furthermore, with enhancing the applied magnetic field, separation of former degenerate levels increases and also avoided crossings (anti-crossing) in the energy spectra is detected. It is also discussed how the energy levels of the system can be adjusted with variation of temperature as well as the magnetic field and geometrical sizes.

  8. Synergistic Interactions within a Multispecies Biofilm Enhance Individual Species Protection against Grazing by a Pelagic Protozoan

    Directory of Open Access Journals (Sweden)

    Prem K. Raghupathi

    2018-01-01

    Full Text Available Biofilm formation has been shown to confer protection against grazing, but little information is available on the effect of grazing on biofilm formation and protection in multispecies consortia. With most biofilms in nature being composed of multiple bacterial species, the interactions and dynamics of a multispecies bacterial biofilm subject to grazing by a pelagic protozoan predator were investigated. To this end, a mono and multispecies biofilms of four bacterial soil isolates, namely Xanthomonas retroflexus, Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus, were constructed and subjected to grazing by the ciliate Tetrahymena pyriformis. In monocultures, grazing strongly reduced planktonic cell numbers in P. amylolyticus and S. rhizophila and also X. retroflexus. At the same time, cell numbers in the underlying biofilms increased in S. rhizophila and X. retroflexus, but not in P. amylolyticus. This may be due to the fact that while grazing enhanced biofilm formation in the former two species, no biofilm was formed by P. amylolyticus in monoculture, either with or without grazing. In four-species biofilms, biofilm formation was higher than in the best monoculture, a strong biodiversity effect that was even more pronounced in the presence of grazing. While cell numbers of X. retroflexus, S. rhizophila, and P. amylolyticus in the planktonic fraction were greatly reduced in the presence of grazers, cell numbers of all three species strongly increased in the biofilm. Our results show that synergistic interactions between the four-species were important to induce biofilm formation, and suggest that bacterial members that produce more biofilm when exposed to the grazer not only protect themselves but also supported other members which are sensitive to grazing, thereby providing a “shared grazing protection” within the four-species biofilm model. Hence, complex interactions shape the dynamics of the biofilm and

  9. Aridity and grazing as convergent selective forces: an experiment with an Arid Chaco bunchgrass.

    Science.gov (United States)

    Quiroga, R Emiliano; Golluscio, Rodolfo A; Blanco, Lisandro J; Fernández, Roberto J

    2010-10-01

    It has been proposed that aridity and grazing are convergent selective forces: each one selects for traits conferring resistance to both. However, this conceptual model has not yet been experimentally validated. The aim of this work was to experimentally evaluate the effect of aridity and grazing, as selective forces, on drought and grazing resistance of populations of Trichloris crinita, a native perennial forage grass of the Argentinean Arid Chaco region. We collected seeds in sites with four different combinations of aridity and grazing history (semiarid/ subhumid x heavily grazed/lightly grazed), established them in pots in a common garden, and subjected the resulting plants to different combinations of drought and defoliation. Our results agreed with the convergence model. Aridity has selected T. crinita genotypes that respond better to drought and defoliation in terms of sexual reproduction and leaf growth, and that can evade grazing due to a lower shoot: root ratio and a higher resource allocation to reserves (starch) in stem bases. Similarly, grazing has selected genotypes that respond better to drought and defoliation in terms of sexual reproduction and that can evade grazing due to a lower digestibility of leaf blades. These results allow us to extend concepts of previous models in plant adaptation to herbivory to models on plant adaptation to drought. The only variable in which we obtained a result opposite to predictions was plant height, as plants from semiarid sites were taller (and with more erect tillers) than plants from subhumid sites; we hypothesize that this result might have been a consequence of the selection exerted by the high solar radiation and soil temperatures of semiarid sites. In addition, our work allows for the prediction of the effects of dry or wet growing seasons on the performance of T. crinita plants. Our results suggest that we can rely on dry environments for selecting grazing-resistant genotypes and on high grazing pressure

  10. Effects of Grazing Management and Cattle on Aquatic Habitat Use by the Anuran Pseudopaludicola mystacalis in Agro-Savannah Landscapes.

    Directory of Open Access Journals (Sweden)

    Rodolfo M Pelinson

    Full Text Available Because of their strong dependence on the environment, the spatial distribution of pond-breeding amphibians can be greatly influenced by anthropogenic habitat alteration. In some agricultural landscapes in Brazil, the anuran Pseudopaludicola mystacalis appears to be highly influenced by land use. Because adult males and tadpoles of this species are usually found in marshy areas with cattle hoof prints, we hypothesized that P. mystacalis preferentially occupies aquatic habitats with marshy areas that are trampled by cattle. To test our hypothesis, we assessed whether the occurrence of P. mystacalis is associated with the presence of cattle and trampled marshy areas, and which environmental features best explain the spatial distribution and abundance of P. mystacalis. To do so, we sampled 38 aquatic habitats in an area intensely used for livestock in southeastern Brazil. We found that the presence of cattle and trampled marshy areas in aquatic habitats are positively associated to P. mystacalis occurrence. Additionally, the abundance of calling males is better predicted by variables of landscape and local habitat structure. Specifically, the size of trampled marshy areas and the proportion of herbaceous vegetation within the aquatic habitat are positively associated with abundance, while distance to nearest aquatic habitat are negatively associated with abundance of calling males. All three of these variables can be directly or indirectly linked to the presence of cattle or grazing management. Therefore, this work shows evidence that Pseudopaludicola mystacalis is positively influenced by grazing management with cattle, and draws attention to other unknown potential consequences of different land use to fresh water diversity.

  11. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2.s(-1 and clipping (2.06 μmol.m(-2.s(-1 than under grazing (1.65 μmol.m-(2.s(-1 over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP. Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content and biotic (ANPP and BNPP factors regulate soil respiration in the semiarid temperate grassland of northern China.

  12. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Science.gov (United States)

    Wang, Zhen; Ji, Lei; Hou, Xiangyang; Schellenberg, Michael P

    2016-01-01

    Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2).s(-1)) and clipping (2.06 μmol.m(-2).s(-1)) than under grazing (1.65 μmol.m-(2).s(-1)) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.

  13. Integrated modelling of anthropogenic land-use and land-cover change on the global scale

    Science.gov (United States)

    Schaldach, R.; Koch, J.; Alcamo, J.

    2009-04-01

    In many cases land-use activities go hand in hand with substantial modifications of the physical and biological cover of the Earth's surface, resulting in direct effects on energy and matter fluxes between terrestrial ecosystems and the atmosphere. For instance, the conversion of forest to cropland is changing climate relevant surface parameters (e.g. albedo) as well as evapotranspiration processes and carbon flows. In turn, human land-use decisions are also influenced by environmental processes. Changing temperature and precipitation patterns for example are important determinants for location and intensity of agriculture. Due to these close linkages, processes of land-use and related land-cover change should be considered as important components in the construction of Earth System models. A major challenge in modelling land-use change on the global scale is the integration of socio-economic aspects and human decision making with environmental processes. One of the few global approaches that integrates functional components to represent both anthropogenic and environmental aspects of land-use change, is the LandSHIFT model. It simulates the spatial and temporal dynamics of the human land-use activities settlement, cultivation of food crops and grazing management, which compete for the available land resources. The rational of the model is to regionalize the demands for area intensive commodities (e.g. crop production) and services (e.g. space for housing) from the country-level to a global grid with the spatial resolution of 5 arc-minutes. The modelled land-use decisions within the agricultural sector are influenced by changing climate and the resulting effects on biomass productivity. Currently, this causal chain is modelled by integrating results from the process-based vegetation model LPJmL model for changing crop yields and net primary productivity of grazing land. Model output of LandSHIFT is a time series of grid maps with land-use/land-cover information

  14. The Marshall Grazing Incidence X-ray Spectrometer

    Science.gov (United States)

    Kobayashi, Ken; Winebarger, Amy R.; Savage, Sabrina; Champey, Patrick; Cheimets, Peter N.; Hertz, Edward; Bruccoleri, Alexander R.; Golub, Leon; Ramsey, Brian; Ranganathan, Jaganathan; Marquez, Vanessa; Allured, Ryan; Parker, Theodore; Heilmann, Ralf K.; Schattenburg, Mark L.

    2017-08-01

    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument designed to obtain spatially resolved soft X-ray spectra of the solar atmosphere in the 6-24 Å (0.5-2.0 keV) range. The instrument consists of a single shell Wolter Type-I telescope, a slit, and a spectrometer comprising a matched pair of grazing incidence parabolic mirrors and a planar varied-line space diffraction grating. The instrument is designed to achieve a 50 mÅ spectral resolution and 5 arcsecond spatial resolution along a +/-4-arcminute long slit, and launch is planned for 2019. We report on the status and our approaches for fabrication and alignment for this novel optical system. The telescope and spectrometer mirrors are replicated nickel shells, and are currently being fabricated at the NASA Marshall Space Flight Center. The diffraction grating is currently under development by the Massachusetts Institute of Technology (MIT); because of the strong line spacing variation across the grating, it will be fabricated through e-beam lithography.

  15. Subacute ruminal acidosis (SARA) in grazing Irish dairy cows.

    Science.gov (United States)

    O'Grady, Luke; Doherty, Michael L; Mulligan, Finbar J

    2008-04-01

    Subacute ruminal acidosis (SARA) is a significant production disease of dairy cattle. Previous concerns have been raised over the occurrence of SARA in pasture-fed dairy cattle and the potential consequences of laminitis and lameness. Highly digestible perennial rye grass contains high concentrations of rapidly fermentable carbohydrate and low concentrations of physical effective fibre that may result in SARA. This study conducted a point prevalence survey of rumen health status in grazing Irish dairy cattle fed predominantly perennial rye grass-based pasture. The survey assessed rumen fluid, animal health status, milk production data and pasture composition. A total of 144 cows between 80 and 150 days in milk were sampled on 12 farms. Eleven percent of cows were classified as affected with SARA (pH 5.8). The study showed that low rumen pH is prevalent in grazing Irish dairy cattle consuming perennial rye grass-based pasture and raises concerns regarding effective pasture utilisation and possible consequences for animal health.

  16. Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing

    Science.gov (United States)

    Antia, A. N.; Suffrian, K.; Holste, L.; Müller, M. N.; Nejstgaard, J. C.; Simonelli, P.; Carotenuto, Y.; Putzeys, S.

    2008-01-01

    Independent of the ongoing acidification of surface seawater, the majority of the calcium carbonate produced in the pelagial is dissolved by natural processes above the lysocline. We investigate to what extent grazing and passage of coccolithophorids through the guts of copepods and the food vacuoles of microzooplankton contribute to calcite dissolution. In laboratory experiments where the coccolithophorid Emiliania huxleyi was fed to the rotifer Brachionus plicatilis, the heterotrophic flagellate Oxyrrhis marina and the copepod Acartia tonsa, calcite dissolution rates of 45-55%, 37-53% and 5-22% of ingested calcite were found. We ascribe higher loss rates in microzooplankton food vacuoles as compared to copepod guts to the strongly acidic digestion and the individual packaging of algal cells. In further experiments, specific rates of calcification and calcite dissolution were also measured in natural populations during the PeECE III mesocosm study under differing ambient pCO2 concentrations. Microzooplankton grazing accounted for between 27 and 70% of the dynamic calcite stock being lost per day, with no measurable effect of CO2 treatment. These measured calcite dissolution rates indicate that dissolution of calcite in the guts of microzooplankton and copepods can account for the calcite losses calculated for the global ocean using budget and model estimates.

  17. Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

    Directory of Open Access Journals (Sweden)

    Roberta Carrilho Canesin

    2014-04-01

    Full Text Available Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG, efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI, dry matter and organic matter digestibility (DMD and OMD, BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD, once daily except Saturdays and Sundays (SS, or on alternate days (AD, at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.

  18. Effect of the Silica Content of Diatoms on Protozoan Grazing

    Directory of Open Access Journals (Sweden)

    Shuwen Zhang

    2017-06-01

    Full Text Available This study examined the effect that silica content in diatom cells has on the behavior of protists. The diatoms Thalassiosira weissflogii and T. pseudonana were cultured in high or low light conditions to achieve low and high silica contents, respectively. These cells were then fed to a heterotrophic dinoflagellate Noctiluca scintillans and a ciliate Euplotes sp. in single and mixed diet experiments. Our results showed that in general, N. scintillans and Euplotes sp. both preferentially ingested the diatoms with a low silica content rather than those with a high silica content. However, Euplotes sp. seemed to be less influenced by the silica content than was N. scintillans. In the latter case, the clearance and ingestion rate of the low silica diatoms were significantly higher, both in the short (6-h and long (1-d duration grazing experiments. Our results also showed that N. scintillans required more time to digest the high silica-containing cells. As the high silica diatoms are harder to digest, this might explain why N. scintillans exhibits a strong preference for the low silica prey. Thus, the presence of high silica diatoms might limit the ability of the dinoflagellate to feed. Our findings suggest that the silica content of diatoms affects their palatability and digestibility and, consequently, the grazing activity and selectivity of protozoan grazers.

  19. 'The Finn line' - a historical curiosity or a juridicial rality? The Sami reindeer herders' land rights in southern Sami areas evaluated from land consolidation practice (In Norwegian with Summary in English

    Directory of Open Access Journals (Sweden)

    Øyvind Ravna

    2005-04-01

    Full Text Available Attitudes towards the land rights of Sami reindeer herders have changed considerably during the last 100 years. So, too, has consideration of how such rights should be treated by Land Consolidation Courts. This paper reviews changes in attitudes to the Sami land rights with respect to how these are considered in Land Con¬solidation Courts in southern Sami areas in Norway. The review also considers changing attitudes regarding the competence of Land Consolidation Courts to deal with such matters. There were several cases in the 20th Century in which Land Consolidation Courts treated Sami land rights in a restricted and unfortunate manner. Legal practice, however, was not always like that, evidenced by the so-called 'Finn line' (Norwegian: 'finnelinja' -'Finn' is an archaic name for Sami. This boundary was established during a land consolidation case in 1873 and was confirmed in 1883. At that time, Sami land rights were evidently accepted as appurtenant right in privately owned mountain pasture and the Sami were treated in the same way as others who enjoyed rights of usufruct on it. The regulation of 1883 included rules governing compensation for grazing damage on farming land. In particular, responsibility for grazing damage was divided between owners and the reindeer herders, providing these looked after their animals properly, 'The Finn line' subsequently achieved wider importance. The case of 1873¬1883 has been referred to several times as a valuable and valid precedent for a way in which to organize grazing conflicts in other Sami areas. It was used in 1964 as evidence of the special rights of Sami reindeer people in the Brekken common land case. The Sami won this case in 1968 and, in its judgement, the Norwegian Supreme Court of Justice emphasised the importance of the line (Rt. 1968, p. 394. Although, owing to changes in land use practices, the 'Finn line' no longer has any practical significance, its juridical significance remains

  20. Effects of rare-earth substitution on the stability and electronic structure of REZnOSb (RE = La-Nd, Sm-Gd) investigated via first-principles calculations

    International Nuclear Information System (INIS)

    Guo Kai; Man Zhenyong; Cao Qigao; Chen Haohong; Guo Xiangxin; Zhao Jingtai

    2011-01-01

    Graphical abstract: The structure stability of REZnOSb decreases with varying rare-earth from La to Gd because of the increased binding energy. Research highlights: → As increasing the atomic number of the RE, the structural stability of REZnOSb decreases. → Varying the rare-earth elements from La to Gd, the covalent interactions between [ZnSb] and [LaO] layer are enhanced by 4f-electrons. → The electrical transport properties of REZnOSb could be improved using the large atomic number of the RE. - Abstract: The structural stability, chemical bonding, Mulliken populations, and charge-density distribution of REZnOSb (RE = La-Nd, Sm-Gd) were investigated by first-principles calculations. Unit cell parameters calculated by the generalized gradient approximation (GGA) are in better agreement with experimental results than those derived from the local density approximation (LDA). Binding energy comparisons indicate that the structural stability of REZnOSb decreases with the increment of the atomic number of the RE, as confirmed by X-ray diffraction (XRD) results. Semimetal or narrow band-gap semiconductor behaviors are found for selected REZnOSb. Moreover, chemical bonding analysis shows that there exist considerable polar covalent interactions between the participating atoms. It also reveals that the [ZnSb] layers receive some electrons from the [LaO] layers (donor) as an electrons acceptor and holes transport tunnel. The covalent interactions between the [ZnSb] and [LaO] layers, which are enhanced by 4f-electrons of the RE, are supposed to improve the electrical transport properties.

  1. LAND REFORM IN UKRAINE: HISTORIOGRAPHICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Barantsov B.

    2016-05-01

    s adoption appeared legal framework that allows you to create land market. The Land Code of Ukraine solved question of compliance of Constitution of Ukraine, harmony between rules of the Land Code with rules of land laws and decrees of President of Ukraine. It contains rules of directly of direct action, in contrast to the general declarations. The next step in the development of land relations on the period of 2011 - 2020 years became Decree of the Cabinet of Ministers of Ukraine from 26.10.2011 y. № 1072-р «On approval of the action plan for land reform and create a transparent market of agricultural land» This plan envisages simplification of procedures for establishing of the boundaries of settlements, on amendments to some legislative acts of Ukraine concerning the abolition of free land privatization, about analyzing, systematization, organizing, organizing and bringing to a common electronic format of cadastral information; draft resolution on approval of documents regulating the administration of state land cadastre, approval of the Concept of the National Program of land use and protection, ect. One of the final stages of the land reform in agriculture should be the implementation of land market. The historical review of land reform, evaluation of its positive results and negative effects allow asserting, that in general it was carried overly inconsistently and not always scientifically substantiated. Its end result, due to the transition to a market economy, would be sharing and transfer of land to peasants to private ownership, establishment on this basis of market-oriented farms, implementation of fully functioning land market. The intermediate stages (the transfer of land to collective ownership, issuance of land certificates only slowed reform, the numerous laws and regulations confused its essence and caused many irregularities in land relations.

  2. Vegetation selection by Angus crossbred vs. Raramuri Criollo nursing cows grazing Chihuauan Desert rangeland in summer

    Science.gov (United States)

    We examined vegetation selection patterns of nursing Angus X Hereford crossbred (AH) and Raramuri Criollo (RC) cows grazing Chihuahuan Desert vegetation during the growing season. Eleven cows of each group grazed separately in two large pastures (1190ha, 1165ha) from mid-July until mid-August 2015 (...

  3. Competition between two grass species with and without grazing over a productivity gradient

    NARCIS (Netherlands)

    Kuijper, D.P.J.; Dubbeld, J.; Bakker, J.P.

    2005-01-01

    Soil nutrient-level and herbivory are predicted to have opposing effects on the allocation pattern of the competitive dominant plant species. Lower stem and higher leaf allocation are favoured when plants are grazed, whereas a higher stem allocation is favoured at high nutrient levels. Grazing by

  4. Dairy cattle on Norwegian alpine rangelands – grazing preferences and milk quality

    NARCIS (Netherlands)

    Sickel, H; Abrahamsen, R K; Eldegard, K; Lunnan, T; Norderhaug, A; Petersen, M.A.; Sickel, M.; Steenhuisen, F.; Ohlson, M.

    2014-01-01

    The results from the study ‘Effects of vegetation and grazing preferences on the quality of alpine dairy products’ will be presented. The main objective of the project was to investigate the connections bet - ween alpine rangeland vegetation, landscape use and grazing preferences of free ranging

  5. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Science.gov (United States)

    2010-07-01

    ... livestock use permits. 222.3 Section 222.3 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.3 Issuance of grazing and livestock use permits. (a) Unless otherwise specified by the Chief, Forest Service, all...

  6. Long-term effects of grazing management and buffer strips on soil erosion from pastures

    Science.gov (United States)

    High grazing pressure can lead to soil erosion in pastures by compacting soil and increasing runoff and sediment delivery to waterways. Limited information exists on the effects of grazing management and best management practices (BMPs), such as buffer strips, on soil erosion from pastures. The obje...

  7. Effects of grazing intensity on small mammal population ecology in wet meadows

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Olsen, Henrik; Bildsøe, Mogens

    2005-01-01

    Livestock grazing is common management practice in wet grasslands. However, knowledge of its effects on small mammals is limited. We studied the influence of grazing intensity on small mammals in general and field voles Microtus agrestis in particular in two Danish wet meadows, 1998-2000. General...

  8. Contrasting responses of insect communities to grazing intensity in lowland heathlands

    NARCIS (Netherlands)

    Wallis de Vries, Michiel; Noordijk, Jinze; Colijn, Ed O.; Smit, John T.; Veling, Kars

    2016-01-01

    Grazing at low stocking rates is often recommended for the preservation of the characteristic biodiversity of open landscapes. However, the fine-tuning of grazing management still lacks a good evidence base. This is particularly true for insect communities, as available evidence indicates that

  9. Root Characteristics of Perennial Warm-Season Grasslands Managed for Grazing and Biomass Production

    Directory of Open Access Journals (Sweden)

    Rattan Lal

    2013-07-01

    Full Text Available Minirhizotrons were used to study root growth characteristics in recently established fields dominated by perennial C4-grasses that were managed either for cattle grazing or biomass production for bioenergy in Virginia, USA. Measurements over a 13-month period showed that grazing resulted in smaller total root volumes and root diameters. Under biomass management, root volume was 40% higher (49 vs. 35 mm3 and diameters were 20% larger (0.29 vs. 0.24 mm compared to grazing. While total root length did not differ between grazed and biomass treatments, root distribution was shallower under grazed areas, with 50% of total root length in the top 7 cm of soil, compared to 41% in ungrazed exclosures. These changes (i.e., longer roots and greater root volume in the top 10 cm of soil under grazing but the reverse at 17–28 cm soil depths were likely caused by a shift in plant species composition as grazing reduced C4 grass biomass and allowed invasion of annual unsown species. The data suggest that management of perennial C4 grasslands for either grazing or biomass production can affect root growth in different ways and this, in turn, may have implications for the subsequent carbon sequestration potential of these grasslands.

  10. Case study: dairies utilizing ultra-high stocking density grazing in Pennsylvania and New York

    Science.gov (United States)

    Ultra-high stocking density (UHSD) grazing has gained interest in the forage industry. Proponents of UHSD emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 kg ha**-1 of beef cattle on small paddocks with rest periods of up t...

  11. Effects of livestock grazing on neotropical migratory landbirds in western North America

    Science.gov (United States)

    Carl E. Bock; Victoria A. Saab; Terrell D. Rich; David S. Dobkin

    1993-01-01

    Livestock grazing is a widespread and important influence on neotropical migratory birds in four major ecosystems in western North America: grasslands of the Great Plains and Southwest, riparian woodlands, Intermountain shrubsteppe, and open coniferous forests. We have reviewed available literature on avian responses to grazing in these habitats. Among 35 plains...

  12. Grasshopper responses to fire and postfire grazing in the northern Great Plains vary among species

    Science.gov (United States)

    Rangeland management practices such as burning and grazing management may affect grasshopper populations by impacting development, survival and reproduction. Experiments are lacking in the northern Great Plains examining the effects of fire and grazing intensity on grasshoppers. As part of a larger ...

  13. Some effects of winter grazing of Dohne sour veld | PF | African ...

    African Journals Online (AJOL)

    The utilisation of spared sour veld poses practical problems. As a result of the development of high level protein or nitrogen supplements it has however become possible to efficiently graze spared veld. Results of experiments during three winters where spared sour veld was grazed off either by sheep or by cattle are given.

  14. Physical impact of grazing by sheep on the dynamics of Nama ...

    African Journals Online (AJOL)

    UFS

    Physical impact of sheep grazing on arid Karoo subshrub/grass rangeland,. South Africa ... sustainability of rangeland resources, soil and vegetation responses to various grazing systems (Teague &. Dowhower .... The only significant decrease (F3,4 = 18.14, P <0.01) in basal cover of the total herbaceous layer for the 1995 ...

  15. Grazing management, resilience and the dynamics of a fire driven rangeland system

    NARCIS (Netherlands)

    Anderies, J.M.; Janssen, M.A.; Walker, B.H.

    2002-01-01

    We developed a stylized mathematical model to explore the effects of physical, ecological, and economic factors on the resilience of a managed fire-driven rangeland system. Depending on grazing pressure, the model exhibits one of three distinct configurations: a fire-dominated, grazing-dominated, or

  16. Food supply and demand, a simulation model of the functional response of grazing ruminants

    NARCIS (Netherlands)

    Smallegange, I.M.; Brunsting, A.M.H.

    2002-01-01

    A dynamic model of the functional response is a first prerequisite to be able to bridge the gap between local feeding ecology and grazing rules that pertain to larger scales. A mechanistic model is presented that simulates the functional response, growth and grazing time of ruminants. It is based on

  17. The effect of seasonal grazing on the infiltration capacity of soils in a ...

    African Journals Online (AJOL)

    The infiltration measurements were determined by means of a flood type concentric ring infiltrometer. The results showed that grazing during any one of the seasons reduced the infiltration capacity of the soils. The detrimental effects of summer and autumn grazing were, however, larger titan those of winter and spring ...

  18. Grassland Fire and Cattle Grazing Regulate Reptile and Amphibian Assembly Among Patches

    Science.gov (United States)

    Larson, Danelle M.

    2014-12-01

    Fire and grazing are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle grazing on herpetofauna assemblages in grasslands. A patch-burn grazing study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of grazing, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection rate within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches ( ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and grazing. Local extinctions for reptiles were higher in patches with fire or light grazing ( ɛ ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or grazing. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle grazing, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.

  19. Sierra Nevada grasslands: interactions between livestock grazing and ecosystem structure and function

    Science.gov (United States)

    Barbara H. Allen-Diaz

    2004-01-01

    Livestock grazing plays an integral role in the grass-dominated ecosystems of the Sierra Nevada. Grazing has been asserted to influence such key ecological characteristics as water quality, net primary productivity, nutrient cycling, plant and animal diversity, wildlife habitat availability, and oak regeneration (Belsky and others 1999, Kauffmann and Krueger 1984)....

  20. X-ray diffraction study of surface-layer structure in parallel grazing rays

    International Nuclear Information System (INIS)

    Shtypulyak, N.I.; Yakimov, I.I.; Litvintsev, V.V.

    1989-01-01

    An x-ray diffraction method is described for study of thin polycrystalline and amorphous films and surface layers in an extremely asymmetrical diffraction system in parallel grazing rays using a DRON-3.0 diffractometer. The minimum grazing angles correspond to diffraction under conditions of total external reflection and a layer depth of ∼ 2.5-8 nm

  1. Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

    NARCIS (Netherlands)

    Niane, A.A.

    2013-01-01

    Keywords: Rotational grazing, full protection, continuous grazing species richness,

    species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed

    longevity, rangeland management, Syria.

    Rangelands represent 70% of the semi-arid and arid

  2. Comparison of techniques for estimating herbage intake by grazing dairy cows

    NARCIS (Netherlands)

    Smit, H.J.; Taweel, H.Z.; Tas, B.M.; Tamminga, S.; Elgersma, A.

    2005-01-01

    For estimating herbage intake during grazing, the traditional sward cutting technique was compared in grazing experiments in 2002 and 2003 with the recently developed n-alkanes technique and with the net energy method. The first method estimates herbage intake by the difference between the herbage

  3. Tree-shrub associations in grazed woodlands: First rodents, then cattle?

    NARCIS (Netherlands)

    Smit, C.; Verwijmeren, M.

    2011-01-01

    Spatial associations of tree saplings with spiny or toxic plants in grazed woodlands are generally explained by associational resistance, i. e., protection against grazing via a well-defended neighbor. In this study, we tested whether directed seed dispersal and post-dispersal seed removal by wood

  4. Effects of buffer strips and grazing management on soil loss from pastures

    Science.gov (United States)

    Intensive grazing pressure can cause soil erosion from pastures causing increased sediment loading to aquatic systems. The objectives of this work were to determine the long-term effects of grazing management and buffer strips on soil erosion from pastures fertilized with broiler litter. Field stud...

  5. Voluntary automatic milking in combination with grazing of dairy cows : Milking frequency and effects on behaviour

    NARCIS (Netherlands)

    Ketelaar-de Lauwere, C.C.; Ipema, A.H.; Ouwerkerk, van E.N.J.; Hendriks, M.M.W.B.; Metz, J.H.M.; Noordhuizen, J.P.T.M.; Schouten, W.G.P.

    1999-01-01

    Automatic milking systems (AMS) enable cows to be milked without human interference. Such systems are more acceptable to consumers and from the animal welfare point of view if they can be combined with grazing in the summer season. In this study, grazing was combined with fully automatic milking for

  6. Gradients in fracture force and grazing resistance across canopy layers in seven tropical grass species

    NARCIS (Netherlands)

    Jacobs, A.A.A.; Scheper, J.A.; Benvenutti, M.A.; Gordon, I.J.; Poppi, D.P.; Elgersma, A.

    2013-01-01

    In reproductive swards, stems can act as a barrier that affects the grazing behaviour of ruminant livestock. The barrier effect of stems is closely associated with both the force required to fracture the stems and the density of these stems (in combination, these make up grazing resistance), and

  7. Tillering dynamics in pastures of guinea grass subjected to grazing severities under intermittent stocking

    Directory of Open Access Journals (Sweden)

    Denise Baptaglin Montagner

    2012-03-01

    Full Text Available This experiment was carried out to analyze the tillering dynamics of the species Panicum maximum cv. Mombaca subjected to three post-grazing heights: residue of 30 cm (30; residue of 50 cm (50; and residue of 50 cm during spring and summer, lowered to 40 cm in the first fall season grazing and to 30 cm in the following grazing cycle, resuming to 50 cm after the first grazing of the following spring season (50-30. Grazings were initiated whenever the swards intercepted 95% of the incident light. The post-grazing heights were allocated in the experimental units in a completely randomized block design with three replications. The density of basal tillers did not vary between the residual heights evaluated. Swards managed with variable residual height (50-30 presented higher rates of appearance and mortality of basal tillers during the summer of 2007, indicating high tiller renovation. Regardless of the post-grazing height evaluated, lower rates of appearance of basal tillers were found in the spring of 2006. The stability index of guinea grass cv. Mombaca was close to 1.0 throughout the experimental period. Swards managed with variable post-grazing present structural changes able to improve the regrowth vigor, which may be important to maximize the use of the forage species in the production system.

  8. Does grazing management matter for soil carbon sequestration in shortgrass steppe?

    Science.gov (United States)

    Considerable uncertainty remains regarding the potential of grazing management on semiarid rangelands to sequester soil carbon. Short-term (less than 1 decade) studies have determined that grazing management potentially influences fluxes of carbon, but such studies are strongly influenced by prevail...

  9. Acoustic monitoring system to quantify ingestive behavior of free-grazing cattle

    Science.gov (United States)

    Methods to estimate intake in grazing livestock include using markers, visual observation, mechanical sensors that respond to jaw movement and acoustic recording. In most of the acoustic monitoring studies, the microphone is inverted on the forehead of the grazing livestock and the skull is utilize...

  10. Changes in semi-arid plant species associations along a livestock grazing gradient.

    Directory of Open Access Journals (Sweden)

    Hugo Saiz

    Full Text Available In semi-arid ecosystems, vegetation is heterogeneously distributed, with plant species often associating in patches. These associations between species are not constant, but depend on the particular response of each species to environmental factors. Here, we investigated how plant species associations change in response to livestock grazing in a semi-arid ecosystem, Cabo de Gata-Níjar Natural Park in South East Spain. We established linear point-intercept transects at four sites with different grazing intensity, and recorded all species at each point. We investigated plant associations by comparing the number of times that each pair of species occurred at the same spatial point (co-occurrences, with the expected number of times based on species abundances. We also assessed associations for each shrub and grass species by considering all their pairs of associations and for the whole plant community by considering all pairs of associations on each site. At all sites, the plant community had a negative pattern of association, with fewer co-occurrences than expected. Negative association in the plant community increased at maximum grazing intensity. Most species associated as expected, particularly grass species, and positive associations were most important at intermediate grazing intensities. No species changed its type of association along the grazing gradient. We conclude that in the present plant community, grazing-resistant species compete among themselves and segregate in space. Some shrub species act as refuges for grazing-sensitive species that benefit from being spatially associated with shrub species, particularly at intermediate grazing intensities where positive associations were highest. At high grazing intensity, these shrubs can no longer persist and positive associations decrease due to the disappearance of refuges. Spatial associations between plant species and their response to grazing help identify the factors that organize

  11. Bison grazing increases arthropod abundance and diversity in a tallgrass prairie.

    Science.gov (United States)

    Moran, Matthew D

    2014-10-01

    How grazing-induced ecosystem changes by ungulates indirectly affect other consumers is a question of great interest. I investigated the effect of grazing by American Bison (Bos bison L.) on an arthropod community in tallgrass prairie. Grazing increased the abundance of arthropods, an increase that was present in both herbivorous and carnivorous assemblages, but not in detritivores. The increase in herbivores and reduction in plant biomass from grazing resulted in an arthropod herbivore load almost three times higher in grazed plots compared with controls. Among herbivores, the sap-feeding insect guild was dramatically more abundant, while chewing herbivores were not affected. Herbivorous and carnivorous arthropod richness was higher in grazed plots, although the response was strongest among herbivores. Arthropod abundance on individual grasses and forbs was significantly higher in grazed areas, while plant type had no effect on abundance, indicating that the change was ecosystem-wide and not simply in response to a reduction in grass biomass from grazing. The response of arthropods to grazing was strongest in the early part of the growing season. Published research shows that ungulate grazing, although decreasing available biomass to other consumers, enhances plant quality by increasing nitrogen level in plants. The arthropod results of this study suggest higher plant quality outweighs the potential negative competitive effects of plant biomass removal, although other activities of bison could not be ruled out as the causative mechanism. Because arthropods are extremely abundant organisms in grasslands and a food source for other consumers, bison may represent valuable management tools for maintaining biodiversity.

  12. Grazing alters net ecosystem C fluxes and the global warming potential of a subtropical pasture.

    Science.gov (United States)

    Gomez-Casanovas, Nuria; DeLucia, Nicholas J; Bernacchi, Carl J; Boughton, Elizabeth H; Sparks, Jed P; Chamberlain, Samuel D; DeLucia, Evan H

    2018-03-01

    The impact of grazing on C fluxes from pastures in subtropical and tropical regions and on the environment is uncertain, although these systems account for a substantial portion of global C storage. We investigated how cattle grazing influences net ecosystem CO 2 and CH 4 exchange in subtropical pastures using the eddy covariance technique. Measurements were made over several wet-dry seasonal cycles in a grazed pasture, and in an adjacent pasture during the first three years of grazer exclusion. Grazing increased soil wetness but did not affect soil temperature. By removing aboveground biomass, grazing decreased ecosystem respiration (R eco ) and gross primary productivity (GPP). As the decrease in R eco was larger than the reduction in GPP, grazing consistently increased the net CO 2 sink strength of subtropical pastures (55, 219 and 187 more C/m 2 in 2013, 2014, and 2015). Enteric ruminant fermentation and increased soil wetness due to grazers, increased total net ecosystem CH 4 emissions in grazed relative to ungrazed pasture (27-80%). Unlike temperate, arid, and semiarid pastures, where differences in CH 4 emissions between grazed and ungrazed pastures are mainly driven by enteric ruminant fermentation, our results showed that the effect of grazing on soil CH 4 emissions can be greater than CH 4 produced by cattle. Thus, our results suggest that the interactions between grazers and soil hydrology affecting soil CH 4 emissions play an important role in determining the environmental impacts of this management practice in a subtropical pasture. Although grazing increased total net ecosystem CH 4 emissions and removed aboveground biomass, it increased the net storage of C and decreased the global warming potential associated with C fluxes of pasture by increasing its net CO 2 sink strength. © 2017 by the Ecological Society of America.

  13. 25 CFR 166.309 - Who determines livestock class and livestock ownership requirements on permitted Indian land?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who determines livestock class and livestock ownership... livestock class and livestock ownership requirements on permitted Indian land? (a) Tribes determine the class of livestock and livestock ownership requirements for livestock that may be grazed on range units...

  14. 43 CFR 4.477 - Findings of fact and decision by administrative law judge: Notice; submission to Board of Land...

    Science.gov (United States)

    2010-10-01

    ... presenting proposed findings and conclusions, the administrative law judge shall make findings of fact and... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Findings of fact and decision by... Grazing Districts) § 4.477 Findings of fact and decision by administrative law judge: Notice; submission...

  15. 25 CFR 166.100 - What special tribal policies will we apply to permitting on Indian agricultural lands?

    Science.gov (United States)

    2010-04-01

    ... preferences in permits advertised for bid under § 166.221 of this part, by allowing prospective Indian operators to match the highest responsible bid (unless the tribal law or leasing policy specifies some other... THE INTERIOR LAND AND WATER GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 166.100...

  16. Short-term winter wheat (Triticum aestivum L.) cover crop grazing influence on calf growth, grain yield, and soil properties

    Science.gov (United States)

    Winter cover cropping has many agronomic benefits and can provide forages base for spring livestock grazing. Winter cover crop grazing has shown immediate economic benefits through increased animal production. Winter wheat pasture grazing is common in beef cow-calf production and stocker operations....

  17. Non-traditional Forages in a Managed Grazing System for Control of Gastrointestinal Parasites in Sheep: Preliminary Work

    Science.gov (United States)

    This project compared lambs grazing forage chicory (Cichorium intybus L.) with lambs grazing brown mid-rib forage sorghum (Sorghum bicolor (L.) Moench.) x sudangrass (Sorghum sudanense Piper) hybrid (BMR) to determine if anti-parasitic effects of chicory could be demonstrated. Lambs grazed these fo...

  18. Image processing for grazing incidence fast atom diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Debiossac, Maxime; Roncin, Philippe, E-mail: philippe.roncin@u-psud.fr

    2016-09-01

    Grazing incidence fast atom diffraction (GIFAD, or FAD) has developed as a surface sensitive technique. Compared with thermal energies helium diffraction (TEAS or HAS), GIFAD is less sensitive to thermal decoherence but also more demanding in terms of surface coherence, the mean distance between defects. Such high quality surfaces can be obtained from freshly cleaved crystals or in a molecular beam epitaxy (MBE) chamber where a GIFAD setup has been installed allowing in situ operation. Based on recent publications by Atkinson et al. (2014) and Debiossac et al. (2014), the paper describes in detail the basic steps needed to measure the relative intensities of the diffraction spots. Care is taken to outline the underlying physical assumptions.

  19. GRAZING BEHAVIOUR OF DAIRY COWS ON MOUNTAIN FARM

    Directory of Open Access Journals (Sweden)

    J. VOŘÍŠKOVÁ

    2009-10-01

    Full Text Available The etological observation was provided on a dairy herd (65 Czech Fleckvieh and 51 Holstein cows on a low-input mountain farm during the pasture season (April – October 2008. The milking was provided two-times a day in the stalls. The 24-hours observations were made four-times: in June, July, September and October, in 10- minutes intervals. The cows spent 25 to 38 % of a day on average by feeding and 18 to 22 % on average by moving (stalls – pasture movements took about half of this period. The resting time consisting of chewing was found unsufficient and took 29 % to 40 % of a day on average. Better comfort of cows given by an improved milking technology and a more effective grazing management connected with longer time spent by resting is suggested to achieve higher milk yields on the farm.

  20. Goats on alpine grazing: study on metabolic and hematologic profiles

    Directory of Open Access Journals (Sweden)

    A. Gaviraghi

    2011-03-01

    Full Text Available Summering on alpine pastures from June to October has long been the traditional management of goat flocks in the mountain areas of Lombardy. At present most of the 50.000 goats farmed in Lombardy are still summered, even though only a few thousands - belonging to local breed - are regularly milked. For these goats summering appears to be fundamental not only to allow milk production but also to restore body reserves. The increasing interest in commercial goat milk production in Lombardy involves mainly intensive farming with zero or minimum grazing. However, semi-extensive goat milk production, including summering, could respond to social and environmental goals (Citterio et al., 2002 being able to exploit some economic opportunities...

  1. Actinide concentrations in tissues from cattle grazing a contaminated range

    International Nuclear Information System (INIS)

    Smith, D.D.; Bernhardt, D.E.

    1977-01-01

    Actinide concentrations in the tissues of beef animals periodically sacrificed and sampled during a 3-year grazing study on a plutonium-contaminated range of the Nevada Test Site are discussed. Actinide concentrations in the skeletons of the cows originally introduced into the study areas showed little increase with increased time of exposure, while those of animals born in the study areas showed a continued upward trend with time. Plutonium-239/americium-241 ratios in tissues and ingesta suggest little differentiation in the uptake of these radionuclides. However, the plutonium-239/plutonium-238 ratios indicate that plutonium-238 is more readily absorbed. The gonadal concentrations of the actinides were significantly higher than those of blood and muscle and approached those of bone. These data indicate that consideration should be given to the plutonium-239 dose to gonads as well as that to bone, liver, and lungs of man

  2. Active Micro structured Optical Arrays of Grazing Incidence Reflectors

    International Nuclear Information System (INIS)

    Willingale, R.; Feldman, Ch.; Michette, A.; Hart, D.; McFaul, Ch; Morrison, G.R.; Pfauntsch, S.; Powell, A.K.; Sahraei, Sh.; Shand, M.T.; Button, T.; Rodriguez-Sanmartin, D.; Zhang, D.; Dunare, C.; Parkes, W.; Stevenson, T.; Folkard, M.; Vojnovic, B.; Vojnovic, B.

    2011-01-01

    The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is micro structured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to poly capillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the micro probing of biological cells and tissue samples using Ti Ka radiation (4.5?keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics

  3. A model of ammonia volatilization from a grazing livestock farm

    Science.gov (United States)

    Hutchings, N. J.; Sommer, S. G.; Jarvis, S. C.

    A dynamic model was developed to predict the ammonia volatilization from grazing livestock farms and to allow potential control measures to be evaluated. The relationships within the model were based on the underlying physical and chemical processes but empirically based factors were used to reduce the demand for input data and where the understanding of the underlying processes was inadequate. On a daily basis, the model simulates the partitioning of dietary nitrogen into dung and urine and its subsequent fate within the pasture or the slurry handling system. The fate of dry matter and water added in dung, urine and from other sources is also predicted. The model illustrates the indirect interactions between ammonia sources, highlights the influence of slurry management on ammonia losses, stresses the need for integrated, whole farm measurements and demonstrates that assessments of the impact of control measures may be misleading unless considered at the scale of the whole farm.

  4. Sympatric cattle grazing and desert bighorn sheep foraging

    Science.gov (United States)

    Garrison, Kyle R.; Cain, James W.; Rominger, Eric M.; Goldstein, Elise J.

    2015-01-01

    Foraging behavior affects animal fitness and is largely dictated by the resources available to an animal. Understanding factors that affect forage resources is important for conservation and management of wildlife. Cattle sympatry is proposed to limit desert bighorn population performance, but few studies have quantified the effect of cattle foraging on bighorn forage resources or foraging behavior by desert bighorn. We estimated forage biomass for desert bighorn sheep in 2 mountain ranges: the cattle-grazed Caballo Mountains and the ungrazed San Andres Mountains, New Mexico. We recorded foraging bout efficiency of adult females by recording feeding time/step while foraging, and activity budgets of 3 age-sex classes (i.e., adult males, adult females, yearlings). We also estimated forage biomass at sites where bighorn were observed foraging. We expected lower forage biomass in the cattle-grazed Caballo range than in the ungrazed San Andres range and lower biomass at cattle-accessible versus inaccessible areas within the Caballo range. We predicted bighorn would be less efficient foragers in the Caballo range. Groundcover forage biomass was low in both ranges throughout the study (Jun 2012–Nov 2013). Browse biomass, however, was 4.7 times lower in the Caballo range versus the San Andres range. Bighorn in the Caballo range exhibited greater overall daily travel time, presumably to locate areas of higher forage abundance. By selecting areas with greater forage abundance, adult females in the Caballo range exhibited foraging bout efficiency similar to their San Andres counterparts but lower overall daily browsing time. We did not find a significant reduction in forage biomass at cattle-accessible areas in the Caballo range. Only the most rugged areas in the Caballo range had abundant forage, potentially a result of intensive historical livestock use in less rugged areas. Forage conditions in the Caballo range apparently force bighorn to increase foraging effort by

  5. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic-Theater 2002. Spectacular Visualizations of our Blue Marble

    Science.gov (United States)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2002-01-01

    Spectacular Visualizations of our Blue Marble The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the 2002 Winter Olympic Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC). See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vertexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nicola Nina climate changes. See the city lights, fishing fleets, gas flares and biomass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  6. Effect of Grazing Behavior on Weight Regain Post-Bariatric Surgery: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nathalia Pizato

    2017-12-01

    Full Text Available Grazing, a type of maladaptive eating behavior, has been associated with poor weight outcomes in bariatric patients. The purpose of this study was to conduct a systematic review of the association between grazing behavior and weight regain post-bariatric surgery. Literature searches, study selection, design of the method, and quality appraisal were carried out by two independent authors. The search strategy was performed until October 2017 in Medline, Embase, Cochrane, Lilacs, Scopus, Web of Science, Google Scholar, ProQuest Dissertation & Theses, and Open Grey. Of a total of 3764 articles, five papers met the inclusion criteria (four original articles and one thesis, comprising 994 subjects, mostly women. The prevalence of grazing behavior ranged from 16.6 to 46.6%, and the highest prevalence of significant weight regain was 47%. The association between grazing and weight regain was observed in four of the five evaluated studies. Our findings support an association between grazing behavior and weight regain after bariatric surgery, regardless of surgery type and contextual concept of grazing. Further studies are needed to confirm the clarity of the real prevalence and interfering factors related to grazing behavior and weight outcomes.

  7. Effects of livestock grazing on grasshopper abundance on a native rangeland in Montana.

    Science.gov (United States)

    O'Neill, Kevin M; Olson, Bret E; Wallander, Roseann; Rolston, Marni G; Seibert, Catherine E

    2010-06-01

    Livestock grazing can affect habitat quality for grasshoppers through effects on food and oviposition site availability, microclimate, and other factors. Because of this, some authors have suggested that grazing programs can be used to help manage pest grasshopper populations. In a 6-yr study, we controlled access of cattle to replicated experimental plots on an Agropyron spicatum/Poa sandbergii pasture to create consistent year-to-year differences in postgrazing plant cover, with resultant affects on microclimate. After sampling grasshoppers multiple times after grazing treatments each summer, we found evidence of between-treatment differences in grasshopper abundance for the entire assemblage during 4 of the 6 yr. Some species, including Melanoplus sanguinipes (perhaps the worse rangeland grasshopper pest in the western United States), tended to be more abundant on ungrazed plots, whereas Melanoplus gladstoni often had greater densities on heavily-grazed plots. The effect of grazing on grasshopper densities in this study was lower in magnitude and less consistent among years than in a study we conducted simultaneously at a nearby site where the vegetation was dominated by the exotic species crested wheatgrass (Agropyron cristatum). Our results generally support proposals that grazing could be used to reduce pest grasshopper densities, although the effectiveness of a particular grazing scheme may vary among sites, years, and grasshopper and vegetation assemblages.

  8. Grazing impact on desert plants and soil seed banks: Implications for seed-eating animals

    Science.gov (United States)

    Pol, Rodrigo G.; Sagario, M. Cecilia; Marone, Luis

    2014-02-01

    We assess whether the knowledge of livestock diet helps to link grazing effects with changes in plant cover and soil seed bank size, aiming at inferring the consequences of grazing on seed-eating animals. Specifically, we test whether continuous and heavy grazing reduce the cover, number of reproductive structures and seed reserves of the same grass species whose seeds are selected and preferred by granivorous animals in the central Monte desert, Argentina. Grass cover and the number of grass spikes usually diminished under grazing conditions in the two localities studied (Telteca and Ñacuñán), and soil seed bank was consistently reduced in all three years evaluated owing to a decline of perennial grass and forb seeds. In particular, the abundance of those seeds selected and preferred by birds and ants (in all cases grass species) declined 70-92% in Ñacuñán, and 52-72% in Telteca. Reduction of perennial grass cover and spike number in grazed sites reinforced the causal link between livestock grazing and the decline of grass soil seed reserves throughout failed plant reproduction. Grass seed bank depletion suggests that grazing may trigger a "cascade" of mechanisms that affect the abundance and persistence of valuable fodder species as well as the availability of seed resources for granivorous animals.

  9. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures.

    Science.gov (United States)

    Romanzin, Alberto; Corazzin, Mirco; Piasentier, Edi; Bovolenta, Stefano

    2018-05-16

    During grazing on Alpine pastures, the use of concentrates in dairy cows' diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion) and Seslerion caeruleae (Seslerion) alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH) to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  10. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures

    Directory of Open Access Journals (Sweden)

    Alberto Romanzin

    2018-05-01

    Full Text Available During grazing on Alpine pastures, the use of concentrates in dairy cows’ diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion and Seslerion caeruleae (Seslerion alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  11. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    Science.gov (United States)

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community.

  12. Effect of water-soluble carbohydrate content in orchardgrass pasture on grazing time and rumen fermentation in dairy cows.

    Science.gov (United States)

    Ueda, Koichiro; Mitani, Tomohiro; Kondo, Seiji

    2016-09-01

    Two experiments were conducted to clarify the effect of water-soluble carbohydrate (WSC) content in orchardgrass pasture on the diurnal distribution of grazing time. Six ruminally cannulated, non-lactating dairy cows were grazed on either of two pastures with different orchardgrass cultivars containing low WSC (LWSC; cultivar: 'Hokkai 28') or high WSC (HWSC; cultivar: 'Harunemidori'). The cows were grazed in morning and evening sessions in experiment 1, whereas the cows were grazed throughout the day in experiment 2. In experiment 1, grazing time of the cows on HWSC was longer than that of the cows on LWSC (P content. © 2015 Japanese Society of Animal Science.

  13. Reproductive performance of ewes grazing lucerne during different periods around mating.

    Science.gov (United States)

    Robertson, S M; Clayton, E H; Friend, M A

    2015-11-01

    High intake of lucerne pastures or feeding of other high quality diets during early pregnancy may increase embryo mortality, negating any benefit of improved nutrition on ovulation rate in ewes. This study was conducted to determine whether grazing ewes on lucerne (Medicago sativa) pastures for 7 days prior to and throughout joining would result in greater foetal numbers than if ewes were removed 7 days after the commencement of joining, or if ewes grazed senescent pasture throughout the joining period. Merino ewes (300) were allocated to two replicates of three treatments, grazing pastures between Days -7 and 36 of an unsynchronised, natural autumn joining. Grazing lucerne to Day 7 of joining resulted in 30% more (Pewe than grazing senescent pasture (1.60±0.07 and 1.31±0.07, respectively), and 19% more lambs marked per ewe joined. Extending grazing of lucerne past Day 7 of joining did not result in additional foetuses per ewe (1.61±0.06) in comparison with only grazing lucerne to Day 7 of joining. Greater than 80% of ewes mated during the first 14 days of joining, and the proportions of ewes returning to oestrus and re-mating (0.18±0.022) and of non-pregnant (0.09±0.017) ewes were similar (P>0.05) among all treatment groups, suggesting no differences between treatments in embryo mortality. Grazing naturally cycling ewes on lucerne prior to and during joinings in autumn is recommended as a means to increase the number of lambs born, although additional gains may not be obtained by grazing past day seven of joining. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Modelling parasite transmission in a grazing system: the importance of host behaviour and immunity.

    Directory of Open Access Journals (Sweden)

    Naomi J Fox

    Full Text Available Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts' immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites' free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes

  15. Grazing intensity on the plant diversity of alpine meadow in the eastern Tibetan plateau

    Directory of Open Access Journals (Sweden)

    Wu Ning

    2004-04-01

    Full Text Available Because ofthe remoteness and harsh conditions of the high-altitude rangelands on the eastern Tibetan Plateau, the relationship between yak grazing and plant diversity has not been so clear although livestock increase was thought as the main issue leading to the degradation of rangeland. In the debate of rangeland degradation, biodiversity loss has been assumed as one of the indicators in the last two decades. In this paper authors measured the effects of different grazing intensities on the plant diversity and the structure of Kobresia pygmaea community in the case-study area, northwestern Sichuan. The results indicated that plant diversity of alpine meadow has different changing trends respectively with the change of grazing intensity and seasons. In June the highest plant diversity occurred in the intensively grazed (HG plots, but in July and September species biodiversity index of slightly grazed (LG plots is higher than other experimental treatments. In August the intermediate grazed (IG plots has the highest biodiversity index. Moreover, it was found that intensively grazing always leads to the increase of plant density, but meanwhile the decrease of community height, coverage and biomass. Over-grazing can change the community structure and lead to the succession from Kobresia pygmaea dominated community to Poa pratensis dominated. Analyzing results comprehensively, it can be suggested that the relationship between grazing intensity and plant diversity is not linear, i.e. diversity index is not as good as other characteristics of community structure to evaluate rangeland degradation on the high altitude situation. The change of biodiversity is so complicated that it can not be explained with the simple corresponding causality.

  16. DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea: application of the dilution technique

    Science.gov (United States)

    Wolfe, Gordon V.; Levasseur, Maurice; Cantin, Guy; Michaud, Sonia

    2000-12-01

    We adapted the dilution technique to study microzooplankton grazing of algal dimethylsulfoniopropionate (DMSP) vs. Chl a, and to estimate the impact of microzooplankton grazing on dimethyl sulfide (DMS) production in the Labrador Sea. Phytoplankton numbers were dominated by autotrophic nanoflagellates in the Labrador basin, but diatoms and colonial Phaeocystis pouchetii contributed significantly to phytomass at several high chlorophyll stations and on the Newfoundland and Greenland shelfs. Throughout the region, growth of algal Chl a and DMSP was generally high (0.2-1 d -1), but grazing rates were lower and more variable, characteristic of the early spring bloom period. Production and consumption of Chl a vs. DMSP followed no clear pattern, and sometimes diverged greatly, likely because of their differing distributions among algal prey taxa and size class. In several experiments where Phaeocystis was abundant, we observed DMS production proportional to grazing rate, and we found clear evidence of DMS production by this haptophyte following physical stress such as sparging or filtration. It is possible that grazing-activated DMSP cleavage by Phaeocystis contributes to grazer deterrence: protozoa and copepods apparently avoided healthy colonies (as judged by relative growth and grazing rates of Chl a and DMSP), and grazing of Phaeocystis was significant only at one station where cells were in poor condition. Although we hoped to examine selective grazing on or against DMSP-containing algal prey, the dilution technique cannot differentiate selective ingestion and varying digestion rates of Chl a and DMSP. We also found that the dilution method alone was poorly suited for assessing the impact of grazing on dissolved sulfur pools, because of rapid microbial consumption and the artifactual release of DMSP and DMS during filtration. Measuring and understanding the many processes affecting organosulfur cycling by the microbial food web in natural populations remain a

  17. Climate change, land use and land surveyors

    OpenAIRE

    van der Molen, P.; Mitchell, D.

    2016-01-01

    Research reveals that the land sector is a major emitter of greenhouse gases. But the land sector has also potential to reduce emissions. Different from other emission sectors like energy and transport, the land sector (in particular the rural area including forests) has the potential to also remove greenhouse gases from the atmosphere through sequestration and storage. This requires land use, land use change and forestry to be managed with respect to climate change goals. Carbon storage has ...

  18. Reaction of cocksfoot (Dactylis glomerata L. in grass-clover mixture on N fertilization and grazing

    Directory of Open Access Journals (Sweden)

    Marcela Andreata-Koren

    2009-09-01

    Full Text Available Grazing is the most common way of using a hill and mountain areas because of their specific agro-ecological conditions. Cocksfoot is a grass with high productivity and quality, and it is very good for sowing in the sward for grazing. Because of its good adaptability to different growing conditions, especially in very dry and cold areas, it is excellent in relation to some other good grasses, which can not be raised in such areas. The aim of the experiment was to determine effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S, and their interaction on the cocksfoot sown in a mixture of smooth-stalked meadow grass (Poa pratensis L. and white clover (Trifolium repens L. in hill mountain areas. In a three-year average, the application of 150 kg ha-1 N had significant impact on cocksfoot population density (number of tillers m-2, and it was 51.4 % higher than the recorded one before grazing (P<0.05 and 42.2 % higher after grazing (P<0.01 in comparison to N0. The application of 150 kg ha-1 N resulted in significantly higher cocksfoot dry matter (DM yield for 38.6 % (P<0.01 and 15.3 % higher cocksfoot share in the total mixture in relation to N0 (P<0.01. Grazing management and grazing management interaction with N rate did not significantly affect the population density of individual years. However, in the three-year average, grazing management significantly affected cocksfoot DM (P<0.01 and its percentage in the total DM mixture (P<0.01. Cattle grazing resulted in 9.9 % higher cocksfoot DM yield and 15.2 % higher cocksfoot percentage in pasture. Interaction of grazing management and N-level had significant influence on the percentage of cocksfoot DM in grass-clover mixture. On cattle grazed areas fertilized with 150 kg ha-1 N, the percentage of cocksfoot DM was the highest (74. 07%, while the lowest percentage of cocksfoot DM was recorded on the sheep grazed areas without N (55.12%.

  19. Grazer-induced chain lenght plasticity reduces grazing risk in a marine diatom

    DEFF Research Database (Denmark)

    Bergkvist, Johanna; Thor, Peter; Jakobsen, Hans Henrik

    2012-01-01

    . marinoi was exposed to chemical cues from caged A. tonsa without physical contact with the responding cells. The reductions in chain length significantly reduced copepod grazing; grazing rates on chains (four cells or more) were several times higher compared to that of single cells. This suggests...... that chain length plasticity is a means for S. marinoi to reduce copepod grazing. In contrast, chain length was not suppressed in cultures exposed to the microzooplankton grazer Gyrodinium dominans. Size-selective predation may have played a key role in the evolution of chain formation and chain length...... plasticity in diatoms...

  20. Human land-use and soil change

    Science.gov (United States)

    Wills, Skye A.; Williams, Candiss O.; Duniway, Michael C.; Veenstra, Jessica; Seybold, Cathy; Pressley, DeAnn

    2017-01-01

    Soil change refers to the alteration of soil and soil properties over time in one location, as opposed to soil variability across space. Although soils change with pedogensis, this chapter focuses on human caused soil change. Soil change can occur with human use and management over long or short time periods and small or large scales. While change can be negative or positive; often soil change is observed when short-term or narrow goals overshadow the other soil’s ecosystem services. Many soils have been changed in their chemical, physical or biological properties through agricultural activities, including cultivation, tillage, weeding, terracing, subsoiling, deep plowing, manure and fertilizer addition, liming, draining, and irrigation. Assessing soil change depends upon the ecosystem services and soil functions being evaluated. The interaction of soil properties with the type and intensity of management and disturbance determines the changes that will be observed. Tillage of cropland disrupts aggregates and decreases soil organic carbon content which can lead to decreased infiltration, increased erosion, and reduced biological function. Improved agricultural management systems can increase soil functions including crop productivity and sustainability. Forest management is most intensive during harvesting and seedling establishment. Most active management in forests causes disturbance of the soil surface which may include loss of forest floor organic materials, increases in bulk density, and increased risk of erosion. In grazing lands, pasture management often includes periods of biological, chemical and physical disturbance in addition to the grazing management imposed on rangelands. Grazing animals have both direct and indirect impacts on soil change. Hoof action can lead to the disturbance of biological crusts and other surface features impairing the soil’s physical, biological and hydrological function. There are clear feedbacks between vegetative systems

  1. e-Dairy: a dynamic and stochastic whole-farm model that predicts biophysical and economic performance of grazing dairy systems.

    Science.gov (United States)

    Baudracco, J; Lopez-Villalobos, N; Holmes, C W; Comeron, E A; Macdonald, K A; Barry, T N

    2013-05-01

    A whole-farm, stochastic and dynamic simulation model was developed to predict biophysical and economic performance of grazing dairy systems. Several whole-farm models simulate grazing dairy systems, but most of them work at a herd level. This model, named e-Dairy, differs from the few models that work at an animal level, because it allows stochastic behaviour of the genetic merit of individual cows for several traits, namely, yields of milk, fat and protein, live weight (LW) and body condition score (BCS) within a whole-farm model. This model accounts for genetic differences between cows, is sensitive to genotype × environment interactions at an animal level and allows pasture growth, milk and supplements price to behave stochastically. The model includes an energy-based animal module that predicts intake at grazing, mammary gland functioning and body lipid change. This whole-farm model simulates a 365-day period for individual cows within a herd, with cow parameters randomly generated on the basis of the mean parameter values, defined as input and variance and co-variances from experimental data sets. The main inputs of e-Dairy are farm area, use of land, type of pasture, type of crops, monthly pasture growth rate, supplements offered, nutritional quality of feeds, herd description including herd size, age structure, calving pattern, BCS and LW at calving, probabilities of pregnancy, average genetic merit and economic values for items of income and costs. The model allows to set management policies to define: dry-off cows (ceasing of lactation), target pre- and post-grazing herbage mass and feed supplementation. The main outputs are herbage dry matter intake, annual pasture utilisation, milk yield, changes in BCS and LW, economic farm profit and return on assets. The model showed satisfactory accuracy of prediction when validated against two data sets from farmlet system experiments. Relative prediction errors were <10% for all variables, and concordance

  2. Dynamic grazing incidence fast atom diffraction during molecular beam epitaxial growth of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, P., E-mail: atkinson@insp.jussieu.fr; Eddrief, M. [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7588, INSP, F-75005 Paris (France); CNRS, UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, F-75005 Paris (France); Etgens, V. H. [CNRS, UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, F-75005 Paris (France); VeDeCom-Université Versailles Saint-Quentin en Yvelines, Versailles (France); Khemliche, H., E-mail: hocine.khemliche@u-psud.fr; Debiossac, M.; Mulier, M.; Lalmi, B.; Roncin, P. [ISMO UMR8214 CNRS-Université Paris-Sud, Orsay F-91400 (France); Momeni, A. [ISMO UMR8214 CNRS-Université Paris-Sud, Orsay F-91400 (France); Univ. Cergy Pontoise, F-95031 Cergy (France)

    2014-07-14

    A Grazing Incidence Fast Atom Diffraction (GIFAD) system has been mounted on a commercial molecular beam epitaxy chamber and used to monitor GaAs growth in real-time. In contrast to the conventionally used Reflection High Energy Electron Diffraction, all the GIFAD diffraction orders oscillate in phase, with the change in intensity related to diffuse scattering at step edges. We show that the scattered intensity integrated over the Laue circle is a robust method to monitor the periodic change in surface roughness during layer-by-layer growth, with oscillation phase and amplitude independent of incidence angle and crystal orientation. When there is a change in surface reconstruction at the start of growth, GIFAD intensity oscillations show that there is a corresponding delay in the onset of layer-by-layer growth. In addition, changes in the relative intensity of different diffraction orders have been observed during growth showing that GIFAD has the potential to provide insight into the preferential adatom attachment sites on the surface reconstruction during growth.

  3. X-ray grazing incidence study of inhomogeneous strain relaxation in Si/SiGe wires

    International Nuclear Information System (INIS)

    Hesse, A.; Zhuang, Y.; Holy, V.; Stangl, J.; Zerlauth, S.; Schaeffler, F.; Bauer, G.; Darowski, N.; Pietsch, U.

    2003-01-01

    The elastic strain relaxation in a series of dry-etched periodic multilayer Si/SiGe wire samples with different etching depths was investigated systematically by means of grazing incidence diffraction (GID). The samples were patterned by holographic lithography and reactive ion etching from a Si/SiGe superlattice grown by molecular beam epitaxy. Scanning electron microscopy and atomic force microscopy were employed to obtain information on the shape of the wires. The inhomogeneous strain distribution in the etched wires and in the non-etched part of the multilayers was derived by means of finite element calculations which were used as an input for simulations of the scattered X-ray intensities in depth dependent GID. The theoretical calculations for the scattered intensities are based on distorted-wave Born approximation. The unperturbed scattering potential was chosen with a reduced optical density corresponding to the ratio of wire width and wire period, in order to reflect the main interaction between the incident X-rays and the patterned samples. The calculations are in good agreement with the experimental data demonstrating the variation of strain relaxation with depth

  4. Grazing systems research: Focusing on the managers-introduction

    Science.gov (United States)

    Translating experimental results into management guidelines or as bases for specific decisions presents a substantial challenge for scientists, advisors and land managers. While inductive reasoning can be a valuable tool in developing general guidelines, particular wholly science-based relationships...

  5. The relative roles of climate and land use in the degradation of a terrestrial ecosystem: a case study from Kjarardalur, West Iceland

    Science.gov (United States)

    Erlendsson, Egill; Gísladóttir, Guðrún

    2016-04-01

    Around AD 870 the virgin environment of Iceland became populated by humans and mammal land herbivores. Since then, the island has lost nearly all of its native birch woodland, resulting in dramatic degradation of landscapes and ecosystems, attributed mainly to over-exploitation of woodlands and late-medieval climate deterioration. As part of policy making in agriculture, a heated debate is ongoing over limitations to sheep grazing in pastures suffering from long-term degradation. In this context the history of climate and land use is of great importance. Those who consider grazing a minimal attribute to land degradation argue that the harsh climate conditions of the little ice age are the primary mechanism behind the current degraded landscape. Others err on the side of caution and propose a careful approach to grazing. This study forms a contribution to the historical context of the impact of grazing upon the Icelandic terrestrial ecosystem. Using the analyses of pollen and spores from coprophilous fungi as principal methods, we present data about historical environmental change from within two different land holdings in Kjarardalur Valley, West Iceland. One dataset comes from within a landholding governed by the chieftain farm Reykholt, the other comes from within the land of the indipendent farm, Norðtunga. In the past the valley was used primarily as a pasture, associated with shielings (organised seasonal grazing). Pollen data from the pasture in Kjarardalur Valley, West Iceland, demonstrate a rapid loss of birch (Betula pubescens) woodland from grazing areas owned by the major farm and institution, Reykholt. The suppressive nature of grazing is demonstrated by the expansion of woodland as soon when animal stocks are reduced, probably as a consequence of the bubonic plague after AD 1402. Resumed exploitation of resources eventually depleted all birch woodland from the Reykholt landholding and precipitated soil erosion. The trajectory of environmental change

  6. Evaluation of Meat and Egg Traits of Beijing-you Chickens Rotationally Grazing on Chicory Pasture in a Chestnut Forest

    Directory of Open Access Journals (Sweden)

    L Meng

    Full Text Available ABSTRACT Barn and cage-fed chickens have presented several problems, such as high rates of infectious disease and consequent antibiotic abuse, poorer chicken health and welfare, and often poorer meat and egg quality compared with free-range chickens. The poultry agroforestry system is becoming increasingly popular in many poultry farms nowadays. In this study, to evaluate the contribution of poultry agroforestry system to enhance some meat and egg traits of Beijing-you chickens, some indexes of meat and egg qualities, some indexes of slaughter traits, and the feed conversion efficiency were investigated in rotational grazing Beijing-you chickens on chicory (Cichorium intybus L. pasture (CGRG group and only free-ranging chickens on bare land without forage (control group in chestnut forest. Results showed that the live body weight, the dressing weight, the thigh muscle weight, and the breast muscle weight were increased (p<0.05 based on the decrease of 15% feed concentration in the CGRG group relative to the control. Furthermore, compared with the control, the crude ash, the essential amino acid content, and the inosinic acid content were increased (p<0.05, and the crude fat contents were decreased (p<0.05 in the thigh and breast muscles, while the yolk cholesterol and the feed conversion ratio were significantly decreased (p<0.05 in the CGRG group. This study would provide a scientific basis and technological support for the large-scale demonstration and application of rotational grazing chickens on the artificial pasture in forest.

  7. Global Change and Helminth Infections in Grazing Ruminants in Europe: Impacts, Trends and Sustainable Solutions

    Directory of Open Access Journals (Sweden)

    Hubertus Hertzberg

    2013-08-01

    Full Text Available Infections with parasitic helminths (nematodes and trematodes represent a significant economic and welfare burden to the global ruminant livestock industry. The increasing prevalence of anthelmintic resistance means that current control programmes are costly and unsustainable in the long term. Recent changes in the epidemiology, seasonality and geographic distribution of helminth infections have been attributed to climate change. However, other changes in environment (e.g., land use and in livestock farming, such as intensification and altered management practices, will also have an impact on helminth infections. Sustainable control of helminth infections in a changing world requires detailed knowledge of these interactions. In particular, there is a need to devise new, sustainable strategies for the effective control of ruminant helminthoses in the face of global change. In this paper, we consider the impact of helminth infections in grazing ruminants, taking a European perspective, and identify scientific and applied priorities to mitigate these impacts. These include the development and deployment of efficient, high-throughput diagnostic tests to support targeted intervention, modelling of geographic and seasonal trends in infection, more thorough economic data and analysis of the impact of helminth infections and greater translation and involvement of end-users in devising and disseminating best practices. Complex changes in helminth epidemiology will require innovative solutions. By developing and using new technologies and models, the use of anthelmintics can be optimised to limit the development and spread of drug resistance and to reduce the overall economic impact of helminth infections. This will be essential to the continued productivity and profitability of livestock farming in Europe and its contribution to regional and global food security.

  8. Analysis of Grazing GNSS Reflections Observed at the Zeppelin Mountain Station, Spitsbergen

    Science.gov (United States)

    Peraza, L.; Semmling, M.; Falck, C.; Pavlova, O.; Gerland, S.; Wickert, J.

    2017-11-01

    A reflectometry station has been set up in 2013 near Ny-Ålesund, Svalbard, at 78.9082°N, 11.9031°E. The main goal of the setup is to resolve the spatial and temporal variations in snow and ice cover, based on reflection power observations at grazing elevations. In this study, we develop a method to map the recorded signal power to the main reflection contributions while also discussing the spatial characteristics of the observations. A spectral analysis resolving differential Doppler between direct and reflected signals is presented to identify reflection contributions for a complete year (2014). Strong water reflections are identified with power ratios higher than 70 dB/Hz and constant Doppler shifts of 0.5-0.6 Hz for all elevations. Contributions with ratios higher than 40 dB/Hz can be related to specular land or glacier reflections, for which Doppler shift usually increases with the elevation angle and the distance between reflection point and receiver. Reflections nearby, around 3-5 km, show differential Doppler of 0.4-0.5 Hz, while for reflections farther than 16 km away, Doppler shift is usually larger than 0.8 Hz. Azimuth variations cause cross-track drift of up to 4° during the observation year. Topography-induced shadowing of very low lying satellites limits the extent of the monitoring area. However, the amount of satellites tracked daily, up to 30, allows the reflectometry station to constantly record reflections over areas with thick snow cover and glaciers. This offers the possibility to compare the derived reflected power with local meteorological data to resolve snow and ice variations on the area.

  9. Modeling impacts of climate change and grazing effects on plant biomass and soil organic carbon in the Qinghai-Tibetan grasslands

    Science.gov (United States)

    Zhang, Wenjuan; Zhang, Feng; Qi, Jiaguo; Hou, Fujiang

    2017-12-01

    The Qinghai Province supports over 40 % of the human population of the Qinghai-Tibetan Plateau (QTP) but occupies about 29 % of its land area, and thus it plays an important role in the plateau. The dominant land cover is grassland, which has been severely degraded over the last decade due to a combination of increased human activities and climate change. Numerous studies indicate that the plateau is sensitive to recent global climate change, but the drivers and consequences of grassland ecosystem change are controversial, especially the effects of climate change and grazing patterns on the grassland biomass and soil organic carbon (SOC) storage in this region. In this study, we used the DeNitrification-DeComposition (DNDC) model and two climate change scenarios (representative concentration pathways: RCP4.5 and RCP8.5) to understand how the grassland biomass and SOC pools might respond to different grazing intensities under future climate change scenarios. More than 1400 grassland biomass sampling points and 46 SOC points were used to validate the simulated results. The simulated above-ground biomass and SOC concentrations were in good agreement with the measured data (R2 0.71 and 0.73 for above-ground biomass and SOC, respectively). The results showed that climate change may be the major factor that leads to fluctuations in the grassland biomass and SOC, and it explained 26.4 and 47.7 % of biomass and SOC variation, respectively. Meanwhile, the grazing intensity explained 6.4 and 2.3 % variation in biomass and SOC, respectively. The project average biomass and SOC between 2015 and 2044 was significantly smaller than past 30 years (1985-2014), and it was 191.17 g C m-2, 63.44 g C kg-1 and 183.62 g C m-2, 63.37 g C kg-1 for biomass and SOC under RCP4.5 and RCP8.5, respectively. The RCP8.5 showed the more negative effect on the biomass and SOC compared with RCP4.5. Grazing intensity had a negative relationship with biomass and positive relationship with SOC

  10. Structure of a monolayer of molecular rotors on aqueous subphase from grazing-incidence X-ray diffraction.

    Science.gov (United States)

    Kaleta, Jiří; Wen, Jin; Magnera, Thomas F; Dron, Paul I; Zhu, Chenhui; Michl, Josef

    2018-03-23

    In situ grazing-incidence X-ray scattering shows that a monolayer of artificial rod-shaped dipolar molecular rotors produced on the surface of an aqueous subphase in a Langmuir trough has a structure conducive to a 2D ferroelectric phase. The axes of the rotors stand an average of 0.83 nm apart in a triangular grid, perpendicular to the surface within experimental error. They carry 2,3-dichlorophenylene rotators near rod centers, between two decks of interlocked triptycenes installed axially on the rotor axle. The analysis is based first on simultaneous fitting of observed Bragg rods and second on fitting the reflectivity curve with only three adjustable parameters and the calculated rotor electron density, which also revealed the presence of about seven molecules of water near each rotator. Dependent on preparation conditions, a minor and variable amount of a different crystal phase may also be present in the monolayer.

  11. Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential

    Science.gov (United States)

    Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. ¼ Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a n...

  12. Modeling the influence from ocean transport, mixing and grazing on phytoplankton diversity

    DEFF Research Database (Denmark)

    Adjou, Mohamed; Bendtsen, Jørgen; Richardson, Katherine

    2012-01-01

    Phytoplankton diversity, whether defined on the basis of functional groups or on the basis of numbers of individual species, is known to be heterogeneous throughout the global ocean. The factors regulating this diversity are generally poorly understood, although access to limiting nutrients...... in generating and maintaining diversity, we apply the model to quantify the potential role of zooplankton grazing and ocean transport for the coexistence of competing species and phytoplankton diversity. We analyze the sensitivity of phytoplankton biomass distributions to different types of grazing functional...... responses and show that preferential grazing on abundant species, for example as formulated by the Holling type III grazing function, is a key factor for maintaining species’ coexistence. Mixing and large-scale advection are shown to potentially have a significant impact on the distribution of phytoplankton...

  13. Grazing incidence optics; Proceedings of the Meeting, Orlando, FL, Apr. 3, 4, 1986

    Science.gov (United States)

    Osantowski, John F. (Editor); Van Speybroeck, Leon (Editor)

    1986-01-01

    Papers are presented on the diffraction-limited performance of grazing incidence optical systems; transverse ray aberrations of Wolter type 1 telescopes; hybrid X-ray telescope systems; surface characterization of grazing incidence optics in the extreme UV and X-ray regions; and the surface roughness properties of synchrotron radiation optics. Topics discussed include the simulation of free-abrasive grinding of grazing incidence mirrors with vertical-honing and flexible blades; mirrors for the Extreme Ultraviolet Explorer; the design and development of conical X-ray imaging mirrors; thermal loading considerations for synchrotron radiation mirrors; and grazing incidence optics for synchrotron radiation insertion-device beams. Consideration is given to the interpretation of glancing incidence scattering measurements; damage processes in short wavelength coated FEL optics; the replication of grain incidence optics; and the assembly and alignment of the Technology Mirror Assembly.

  14. Grazing effects on forage production and botanical composition in a Quercus ithaburensis subs. macrolepis silvopastoral system

    Science.gov (United States)

    Pantera, A.; Papanastasis, V. P.

    2009-04-01

    Grazing is considered as a major factor affecting forage production as well as botanical composition of many silvopastoral systems. In order to study these effects, three pairs of grazed and protected plots were established in a Quercus ithaburensis subsp. macrolepis silvopastoral system. The experiment was carried out in western Greece, 15 km west of the city of Agrinion. Data were collected for two continuous years and included the determination of palatable and unpalatable to animals plant species as well as the botanical composition. The results suggest that heavy grazing decreased biomass production approximately threefold. Grazing also affected number of acorns, botanical composition as well as vegetation cover whereas had no effect on natural regeneration in the study period.

  15. Seasonal variations in abundance, biomass and grazing rates of microzooplankton in a tropical monsoonal estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Gauns, M.; Mochemadkar, S.; Patil, S.; Pratihary, A.K.; Naqvi, S.W.A.; Madhupratap, M.

    Seasonal abundance, composition and grazing rates of microzooplankton (20–200 µm) in the Zuari estuary were investigated to evaluate their importance in food web dynamics of a tropical monsoonal estuary. Average abundances of microzooplankton...

  16. Seasonal grazing and food preference of herbivores in a Posidonia oceanica meadow

    Directory of Open Access Journals (Sweden)

    Andrea Peirano

    2001-12-01

    Full Text Available Seasonal grazing of the fish Sarpa salpa (L., the urchin Paracentrotus lividus Lamarck and the isopods Idotea spp. was compared with the C/N ratio of adult and intermediate leaves and epiphytes of Posidonia oceanica (L. Delile, collected at three different depths. Despite seasonal differences in grazing, herbivores showed preferences throughout the year for adult leaves with more epiphyte and higher N contents. The maximum grazing on adult and intermediate leaves was observed in September and in June for fish and in March for urchins, whereas it was irregular for isopods. Grazing by the three herbivores was not related to their preference for leaves or epiphytes, notwithstanding the seasonal differences in their C and N contents. We concluded that herbivores show no preference for food type throughout the year and that seasonal consumption of P. oceanica is related mainly to herbivore behaviour.

  17. Synergistic Interactions within a Multispecies Biofilm Enhance Individual Species Protection against Grazing by a Pelagic Protozoan

    DEFF Research Database (Denmark)

    Raghupathi, Prem Krishnan; Liu, Wenzheng; Sabbe, Koen

    2018-01-01

    of a multispecies bacterial biofilm subject to grazing by a pelagic protozoan predator were investigated. To this end, a mono and multispecies biofilms of four bacterial soil isolates, namely Xanthomonas retroflexus, Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus, were...

  18. The Development of a Differential Deposition Technique for Figure Correction in Grazing Incidence Optics

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of a physical-vapor-deposition coating technique to correct residual figure errors in grazing-incidence optics. The process involves...

  19. Desertification: overpopulation on dry lands - deserts in the making.

    Science.gov (United States)

    Behrens, S

    1977-10-01

    The U.N.'s conference in Nairobi focused on the problem of desertification in the underdeveloped nations. Population pressures force the overuse of the land - in grazing, cropping, and cutting trees for burning. External factors such as the organization of the societies, the past colonial system in Africa, and the introduction of foreign technologies and fluctuating world food markets have all contributed to desertification. The conference recommended that a fund be started to fight this condition. Such a fund would provide for a full agenda of conservation, research, and public education.

  20. Development of grazing incidence devices for space-borne time of flight mass spectrometry

    Science.gov (United States)

    Cadu, A.; Devoto, P.; Louarn, P.; Sauvaud, J.-A.

    2012-04-01

    Time of flight mass spectrometer is widely used to study space plasmas in planetary and solar missions. This space-borne instrument selects ions in function of their energy through an electrostatic analyzer. Particles are then post-accelerated to energies in the range of 20 keV to cross a carbon foil. At the foil exit, electrons are emitted and separated from ion beam in the time of flight section. A first detector (a Micro-Channel Plate or MCP) emits a start signal at electron arrival and a second one emits a stop signal at incident ion end of path. The time difference gives the speed of the particle and its mass can be calculated, knowing its initial energy. However, current instruments suffer from strong limitations. The post acceleration needs very high voltage power supplies which are heavy, have a high power consumption and imply technical constraints for the development. A typical instrument weighs from 5 to 6 kg, includes a 20 kV power supply, consumes a least 5 W and encounters corona effect and electrical breakdown problems. Moreover, despite the particle high energy range, scattering and straggling phenomena in the carbon foil significantly reduce the instrument overall resolution. Some methods, such as electrostatic focus lenses or reflectrons, really improve mass separation but global system efficiency remains very low because of the charge state dependence of such devices. The main purpose of our work is to replace carbon foil by grazing incidence MCP's - also known as MPO's, for Micro Pore Optics - for electron emission. Thus, incident particles would back-scatter onto the channel inner surface with an angle of a few degrees. With this solution, we can decrease dispersion sources and lower the power supplies to post accelerate ions. The result would be a lighter and simpler instrument with a substantial resolution improvement. We have first simulated MPO's behavior with TRIM and MARLOWE Monte-Carlo codes. Energy scattering and output angle computed

  1. [Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

    Science.gov (United States)

    Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

    2017-12-01

    The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

  2. Livestock grazing and trampling of birds' nests: An experiment using artificial nests

    OpenAIRE

    Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Bakker, Jan P.

    2013-01-01

    The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in five different grazing treatments in an experimental design. We use buried clay pigeon targets as artificial mimics of bird nests to obtain reliable estimates of trampling risk and compare these wit...

  3. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    OpenAIRE

    Schmidt, Niels M; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    Abstract Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western ...

  4. A model for analyzing influence of timber production on lichens for reindeer grazing

    OpenAIRE

    Eriksson, Olof; Sandewall, Mats; Wilhelmsson, Erik

    1987-01-01

    A model for long-term analysis of the influence of timber production on lichens for reindeer grazing (Cladina, Alectoria, Bryoria spp and others) in Sweden is presented. The annual production of and demand for lichens are estimated and compared. Production of these lichens is presumed to set the upper limit for the reindeer population. Reindeer graze on both ground and tree lichens, which both must be accessible in sufficient amounts and at the right times of the year if reindeer husbandry is...

  5. [A comparative study on soil respiration between grazing and fenced typical Leymus chinensis steppe, Inner Mongolia].

    Science.gov (United States)

    Jia, Bingrui; Zhou, Guangsheng; Wang, Fengyu; Wang, Yuhui

    2004-09-01

    With enclosed chamber Method, this paper studied the soil respiration in grazing and fenced typical Leymus chinensis steppes, Inner Mongolia, and its relationships with environmental factors. The results showed that the daily pattern of soil respiration could be expressed as a one-humped curve, and the highest values appeared at 13:00-15:00 in the fenced and grazing plots. The diurnal dynamics of soil respiration mainly depended on the surface temperature at the fenced plots and the soil temperature at 5 cm depth at the grazing plots. In June and July, the average soil respiration rate was 2.7 times greater at the fenced plots than that at the grazing plots, while the difference was not distinct in August and September, which was similar with the change of the belowground biomass. The reason was probably that the plant was influenced differently in different phenological phases by grazing and the change of environmental factors. It showed that human activity may not result in the increase of soil respiration rate. The seasonal dynamics of soil respiration was closely correlated with soil water content at the 0-10 cm depth at the fenced and grazing sites, and the maximum R2 was 0.853 and 0.741, respectively. The difference was that the correlation of soil respiration seasonal dynamics with soil water content was larger at the fenced plots than at the grazing plots. The correlations of soil respiration diurnal and seasonal dynamics with temperature and soil water content at lower profiles were larger than those at deeper profiles at the fenced and grazing sites.

  6. Assessing the impacts of Acacia mearnsii on grazing provision and livestock production

    CSIR Research Space (South Africa)

    Yapi, T

    2012-10-01

    Full Text Available with selective grazing Others: grass invaders, forbs and serge Bare: refers to bare ground RESULTS: Grass species composition and basal cover 0 10 20 30 40 50 60 70 80 Uninvaded Cleared Light Dense Co ver (% ) A. mearnsii invasion status... Light Dense M o is tu re (% ) Acacia mearnsii invasion status P?0.05 CONCLUSIONS and RECOMMENDATIONS Conclusions ?High density invasions of A. mearnsii have negative effects on rangelands productivity ?Removal of A. mearnsii improves grazing...

  7. Land Use and Land Cover Change, and Woody Vegetation Diversity in Human Driven Landscape of Gilgel Tekeze Catchment, Northern Ethiopia

    Directory of Open Access Journals (Sweden)

    Samuale Tesfaye

    2014-01-01

    Full Text Available Land use and land cover (LULC change through inappropriate agricultural practices and high human and livestock population pressure have led to severe land degradation in the Ethiopian highlands. This has led to further degradation such as biodiversity loss, deforestation, and soil erosion. The study examined woody vegetation diversity status and the impact of drivers of change across different LULC types and agroecological zones in Gilgel Tekeze catchment, northern Ethiopian highlands. LULC dynamics were assessed using GIS techniques on 1976, 1986, and 2008 satellite images. Vegetation data were collected from 135 sample plots (20 m × 20 m from five LULC types, namely, forest, shrub-bush, grazing, settlement, and cultivated land, in the three agroecological zones; Kolla, Weyna-Dega, and Dega. Differences in vegetation structure and composition and their relationship to agroecological zones were tested using two-way ANOVA and PCA technique. The results show that vegetation structure and composition significantly differed across all LULC types in different agroecological zones particularly in sapling density, tree height, and shrub height and in each agroecological zone between forest land, shrub-bush land, and settlement area. Overall, Weyna-Dega agroecological zone and the shrub-bush land had more structural and compositional diversity than the other agroecological zones and LULC types.

  8. Grazing-Activated Production of Dimethyl Sulfide (DMS) by two clones of Emiliania huxleyi

    Science.gov (United States)

    Wolfe, Gordon V.; Steinke, Michael

    1996-01-01

    Emiliania huxleyi clones CCMP 370 and CCMP 373 produced similar amounts of dimethylsulfoniopropionate (DMSP) during axenic exponential growth, averaging 109 mM internal DMSP. Both clones had detectable DMSP lyase activity, as measured by production of dimethyl sulfide (DMS) during in vitro assays of crude cell preparations, but activities and conditions differed considerably between clones. Clone 373 had high activity; clone 370 had low activity and required chloride. For both strains, enzyme activity per cell was constant during exponential growth, but little DMS was produced by healthy cells. Rather, DMS production was activated when cells were subjected to physical or chemical stresses that caused cell lysis. We propose that DMSP lyase and DMSP are segregated within these cells and re-action only under conditions that result in cell stress or damage. Such activation occurs during microzooplankton grazing. When these clones were grazed by the dinoflagellate Oxyrrhis marina, DMS was produced; ungrazed cells, as well as those exposed to grazer exudates and associated bacteria, generated no DMS. Grazing of clone 373 produced much more DMS than grazing of clone 370, consistent with their relative in vitro DMSP lyase activities. DMS was only generated when cells were actually being grazed, indicating that ingested cells were responsible for the DMS formation. We suggest that even low levels of grazing can greatly accelerate DMS production.

  9. The effects of grazing intensity on soil processes in a Mediterranean protected area.

    Science.gov (United States)

    Panayiotou, Evaggelia; Dimou, Maria; Monokrousos, Nikolaos

    2017-08-08

    We investigated the temporal and among-site differentiation of soil functionality properties in fields under different grazing intensities (heavy and light) and compared them to those found in their adjacent hedgerows, consisting either of wooden shrubs (Rubus canescens) or of high trees (Populus sp.), during the cold and humid seasons of the year. We hypothesized that greater intensity of grazing would result in higher degradation of the soil system. The grazing factor had a significant effect on soil organic C and N, microbial biomass C, microbial biomass N, microbial activity, and β-glucosidase, while acid phosphatase and urease activity were not found to differ significantly among the management systems. The intensity of grazing affected mostly the chemical properties of soil (organic C and N) and altered significantly the composition of the soil microbial community, as lower C:N ratio of the microbial biomass indicates the dominance of bacteria over fungi in the heavily grazed fields. All estimated biological variables presented higher values in the humid period, although the pattern of differentiation was similar at both sampling times, revealing that site-specific variations were more pronounced than the time-specific ones. Our results indicate that not all C, N, and P dynamics were equally affected by grazing. Management plans applied to pastures, in order to improve soil quality properties and accelerate passive reforestation, should aim at the improvement of soil parameters related primarily to C and secondly to N cycle.

  10. Reduced fine-scale spatial genetic structure in grazed populations of Dianthus carthusianorum.

    Science.gov (United States)

    Rico, Y; Wagner, H H

    2016-11-01

    Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on rates of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep grazing on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep grazing showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of grazing treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep grazing were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep grazing has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep grazing to importantly reduce genetic structure at local scales within restored plant populations.

  11. Grazing preference and utilization of soil fungi by Folsomia candida (Collembola)

    Science.gov (United States)

    Hedenec, Petr; Frouz, Jan

    2016-04-01

    Soil fungi are important food resources for soil fauna. Here we ask whether the collembolan Folsomia candida shows selectivity in grazing between four saprophytic fungi (Penicillium chrysogenum, Penicillium expansum, Absidia glauca, and Cladosporium herbarum), whether grazing preference corresponds to effects on collembolan reproduction, and whether the effects of fungi on grazing and reproduction depends on the fungal substrate, which included three kinds of litter (Alnus glutinosa, Salix caprea, and Quercus robur) and one kind of agar (yeast extract). On agar, Cladosporium herbarum and Absidia glauca were the most preferred fungi and supported the highest collembolan reproduction. On fungal-colonized litter, grazing preference was more affected by litter type than by fungal species whereas collembolan reproduction was affected by both litter type and fungal species. On fungal-colonized litter, the litter type that was most preferred for grazing did not support the highest reproduction, i.e., there was an inconsistency between food preference and suitability. Alder and willow were preferred over oak for grazing, but alder supported the least reproduction.

  12. An agent-based model of cattle grazing toxic Geyer's larkspur.

    Science.gov (United States)

    Jablonski, Kevin E; Boone, Randall B; Meiman, Paul J

    2018-01-01

    By killing cattle and otherwise complicating management, the many species of larkspur (Delphinium spp.) present a serious, intractable, and complex challenge to livestock grazing management in the western United States. Among the many obstacles to improving our understanding of cattle-larkspur dynamics has been the difficulty of testing different grazing management strategies in the field, as the risk of dead animals is too great. Agent-based models (ABMs) provide an effective method of testing alternate management strategies without risk to livestock. ABMs are especially useful for modeling complex systems such as livestock grazing management, and allow for realistic bottom-up encoding of cattle behavior. Here, we introduce a spatially-explicit, behavior-based ABM of cattle grazing in a pasture with a dangerous amount of Geyer's larkspur (D. geyeri). This model tests the role of herd cohesion and stocking density in larkspur intake, finds that both are key drivers of larkspur-induced toxicosis, and indicates that alteration of these factors within realistic bounds can mitigate risk. Crucially, the model points to herd cohesion, which has received little attention in the discipline, as playing an important role in lethal acute toxicosis. As the first ABM to model grazing behavior at realistic scales, this study also demonstrates the tremendous potential of ABMs to illuminate grazing management dynamics, including fundamental aspects of livestock behavior amidst ecological heterogeneity.

  13. Microbial quality of soil from the Pampa biome in response to different grazing pressures

    Directory of Open Access Journals (Sweden)

    Rafael S. Vargas

    2015-06-01

    Full Text Available The aim of this study was to evaluate the impact of different grazing pressures on the activity and diversity of soil bacteria. We performed a long-term experiment in Eldorado do Sul, southern Brazil, that assessed three levels of grazing pressure: high pressure (HP, with 4% herbage allowance (HA, moderate pressure (MP, with 12% HA, and low pressure (LP, with 16% HA. Two reference areas were also assessed, one of never-grazed native vegetation (NG and another of regenerated vegetation after two years of grazing (RG. Soil samples were evaluated for microbial biomass and enzymatic (β-glucosidase, arylsulfatase and urease activities. The structure of the bacterial community and the population of diazotrophic bacteria were evaluated by RFLP of the 16S rRNA and nifH genes, respectively. The diversity of diazotrophic bacteria was assessed by partial sequencing of the 16S rDNA gene. The presence of grazing animals increased soil microbial biomass in MP and HP. The structures of the bacterial community and the populations of diazotrophic bacteria were altered by the different grazing managements, with a greater diversity of diazotrophic bacteria in the LP treatment. Based on the characteristics evaluated, the MP treatment was the most appropriate for animal production and conservation of the Pampa biome.

  14. Soil physical attributes in forms of sowing the annual winter pasture and intervals between grazing

    Directory of Open Access Journals (Sweden)

    Milton da Veiga

    Full Text Available The sowing of winter pastures in areas used for summer grain production and their management under direct cattle grazing can cause changes in soil physical attributes, whose intensity depends on the degree of soil mobilization, grazing interval, stocking rate and weather. To study these aspects it was conducted over four years an experiment in a randomized block with split plots design and four replications. In the main plots were applied two forms of sowing the annual winter pasture (direct seeding and seeding + harrowing and, in the subplots, four intervals between grazing (7, 14 and 28 days and ungrazed. Undisturbed soil cores were sampled at the end of each grazing cycle, in the 0-0.05 m layer to determine the saturated hydraulic conductivity and aggregate stability and in the layers of 0-0.05, 0.05-0.10, 0.10-0.15 and 0.15-0.20 m depth to determine bulk density and classes of soil pores. The direct seeding of annual winter pasture increases hydraulic conductivity and reduces soil bulk density in relation to seeding + harrowing while dairy cows trampling increases soil density and reduces macroporosity in the most superficial soil layer. The variation in climatic conditions among grazing cycles affects the soil physical attributes more markedly than forms of sowing and intervals between grazing of the annual winter pasture.

  15. Species Diversity and Botanical Composition of Permanent Grassland as a Response to Different Grazing Management Practices

    Directory of Open Access Journals (Sweden)

    Marie Štýbnarová

    2015-01-01

    Full Text Available The effects of different levels of grazing utilization (two, three and four grazing cycles per year and mineral fertilization (nil-fertilization; N100P30K60 on the botanical composition of permanent grasslands were studied in the locality of Rapotín (Czech Republic, 332 m a.s.l. from 2003–2010. The vegetation of the experimental pasture was classified as Cynosurion. It was found that moderate treatment (three grazing cycles per year without mineral fertilization showed the highest value of diversity index (DI = 6.08, and maximum dominance of legumes (Dmax = 9.1%, particularly Trifolium repens. The highest dominance of grasses (Dmax = 77.7%, mainly Dactylis glomerata and Elytrigia repens, was achieved with the fertilized treatment utilized in two grazing cycles per year. Based on RDA results, tested management treatments explained 26% of species composition variability, where effect of number of grazing cycles per year was five-times higher than effect of fertilization. We recommend grassland utilization in three grazing cycles per year as the most suitable way from the objective of both species diversity and botanical composition of pastures in similar site conditions. Pasture fertilization should be more controlled by careful consideration of individual pasture goals, actual nutrient status of the soil and possible environmental risks.

  16. Ingestive behavior of supplemented Nellore heifers grazing palisadegrass pastures managed with different sward heights.

    Science.gov (United States)

    Vieira, Bruno Ramalho; Azenha, Mariana Vieira; Casagrande, Daniel Rume; Costa, Diogo Fleury Azevedo; Ruggieri, Ana Cláudia; Berchielli, Telma Teresinha; Reis, Ricardo Andrade

    2017-04-01

    Three sward heights (15, 25 and 35 cm) and three supplement types (energy, energy-protein, and a mineral mix supplement) were evaluated in a 3 × 3 factorial arrangement distributed in a completely randomized design to study changes in forage search patterns in Nellore heifers in a continuous grazing system. Pasture data were collected using two replicates (paddocks) per treatment over four periods during the rainy season. The behavior assessments were made in the first and fourth grazing seasons. It was hypothesized that supplements and pasture management would modify ingestive behavior, considering that animals would require less time grazing if they had energy requirements met through higher digestibility of better managed paddocks, or use of supplements high in energy. Total and green forage masses along with green : dead material ratio were greater in treatments managed with higher sward heights. Sward managed with 35 cm height resulted in lower leaf : stem ratio compared with 15 cm sward height treatments. The animals on the 15 cm pastures spent more time grazing overall and during each meal, but there were no differences observed in meal numbers in comparison to 35 cm treatments. Heifers fed protein and/or energy supplements spent less time grazing in the early afternoon, but overall grazing time was the same for all animals. © 2016 Japanese Society of Animal Science.

  17. Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps

    Science.gov (United States)

    Powell, John Wesley

    1879-01-01

    A report from Maj. J. W.Powell, geologist in charge of the United States Geographical and Geological Survey of the Rocky Mountain Region, upon the lands of the Arid Region of the United States, setting forth the extent of said region, and making suggestions as to the conditions under which the lands embraced within its limit may be rendered available for agricultural and grazing purposes. With the report is transmitted a statement of the rainfall of the western portion of the United States, with reports upon the subject of irrigation by Capt. C. E. Button, U. S. A., Prof. A. H. Thompson, and Mr. G. K. Gilbert.

  18. Land Cover - Minnesota Land Cover Classification System

    Data.gov (United States)

    Minnesota Department of Natural Resources — Land cover data set based on the Minnesota Land Cover Classification System (MLCCS) coding scheme. This data was produced using a combination of aerial photograph...

  19. The fabrication and characterization of replicated and lacquer coated grazing

    International Nuclear Information System (INIS)

    Ulmer, M.P.; Haidle, R.; Altkorn, R.; Georgeopolos, P.; Rodricks, B.; Takacs, P.Z.

    1992-01-01

    This paper reports on work done over the past two years in our laboratory to produce X-ray optics. We also report on tests that we have made to evaluate the performance of pieces that we have produced. As we progress towards the 21st century, there is a growing need to understand fabrication techniques for grazing incidence optics. To this end we report our results of fabricating, testing, and measuring both Wolter I optics and flats. We have used the techniques of lacquer coating. We have made flats to determine our ability to coat surfaces with lacquer and gold, as well as to demonstrate reflectivity up to 40 keV. We also produced Wolter I optics nickel optics with a gold coated optical surface. Here we report and interpret results from X-ray reflectivity and Wyko profiler optical measurements. We also describe our fabrication process and provide a critique of the process and describe how we hope to further improve upon the basic technique

  20. Grazing incidence EUV study of the Alcator tokamaks

    International Nuclear Information System (INIS)

    Castracane, J.

    1982-01-01

    The use of impurity radiation to examine plasma conditions is a well known technique. To gain access, however, to the hot, central portion of the plasma created in the present confinement machines it is necessary to be able to observe radiation from medium and heavy elements such as molybdenum and iron. These impurities radiate primarily in the extreme ultra violet region of the spectrum and can play a role in the power balance of the tokamak. Radiation from highly ionized molybdenum was examined on the Alcator A and C tokamaks using a photometrically calibrated one meter grazing incidence monochromator. On Alcator A, a pseudo-continuum of Mo emissions in the 60 to 100 A ranges were seen to comprise 17% of the radiative losses from the plasma. This value closely matched measurements by a broad band bolometer array. Following these preliminary measurements, the monochromator was transferred to Alcator C for a more thorough examination of EUV emissions. Deviations from predicted scaling laws for energy confinement time vs density were observed on this machine

  1. forage systems mixed with forage legumes grazed by lactating cows

    Directory of Open Access Journals (Sweden)

    Clair Jorge Olivo

    2017-02-01

    Full Text Available Current research evaluates productivity, stocking and nutritional rates of three forage systems with Elephant Grass (EG + Italian Ryegrass (IR + Spontaneous Growth Species (SGS, without forage legumes; EG + IR + SGS + Forage Peanut (FP, mixed with FP; and EG + IR + SGS + Red Clover (RC, mixed with RC, in rotational grazing method by lactating cows. IR developed between rows of EG. FP was maintained, whilst RC was sow to respective forage systems. The experimental design was completely randomized, with three treatments and two replication, subdivided into parcels over time. Mean rate for forage yield and average stocking rate were 10.6, 11.6 and 14.4 t ha-1; 3.0, 2.8 and 3.1 animal unit ha-1 day-1, for the respective systems. Levels of crude protein and total digestible nutrients were 17.8, 18.7 and 17.5%; 66.5, 66.8 and 64.8%, for the respective forage systems. The presence of RC results in better and higher forage yield in the mixture, whilst FP results in greater control of SGS. The inclusion of forage legumes in pasture systems provides better nutritional rates.

  2. Arbuscular mycorrhizal fungi associated with vegetation and soil parameters under rest grazing management in a desert steppe ecosystem.

    Science.gov (United States)

    Bai, Gegenbaoleer; Bao, Yuying; Du, Guoxin; Qi, Yunlong

    2013-05-01

    The impact of rest grazing on arbuscular mycorrhizal fungi (AMF) and the interactions of AMF with vegetation and soil parameters under rest grazing condition were investigated between spring and late summer in a desert steppe ecosystem with different grazing managements (rest grazing with different lengths of resting period, banned or continuous grazing) in Inner Mongolia, China. AMF diversity and colonization, vegetation biomass, soil properties and soil phosphatase activity were examined. In rest grazing areas of 60 days, AMF spore number and diversity index at a 0-10 cm soil depth as well as vesicular and hyphal colonization rates were higher compared with other grazing treatments. In addition, soil organic matter and total N contents were highest and soil alkaline phosphatase was most active under 60-day rest grazing. In August and September, these areas also had the highest amount of aboveground vegetation. The results indicated that resting grazing for an appropriate period of time in spring has a positive effect on AMF sporulation, colonization and diversity, and that under rest grazing conditions, AMF parameters are positively correlated with some soil characteristics.

  3. Vesper Sparrows and Western Meadowlarks Show a Mixed Response to Cattle Grazing in the Intermountain Region of British Columbia

    Directory of Open Access Journals (Sweden)

    Megan L. Harrison

    2010-06-01

    Full Text Available Livestock grazing in the shortgrass steppe of the Intermountain region of British Columbia is predicted to have significant effects on grassland habitats and their associated ground-nesting bird communities. We tested whether grazed and ungrazed sites could be discriminated on the basis of their vegetation communities, whether the abundance of two ground-nesting bird species, Vesper Sparrow (Pooecetes gramineus and Western Meadowlark (Sturnella neglecta, differed between grazed and ungrazed sites, and whether vegetation variables found to differ between grazed and ungrazed plots could be used to predict the abundance of the two bird species at a fine scale. Grazed sites were easily distinguishable from a site that had been ungrazed for >30 years based on the structure and composition of their vegetation communities. However, more detailed grazing categories could not be distinguished on the basis of vegetation characteristics. Despite the existence of grazing effects on vegetation structure and composition, we found no consistent differences in abundance of Vesper Sparrows and Western Meadowlarks between the grazed and ungrazed sites. However, there was weak evidence that the abundance of both species was higher at fine-scale plots (100 m radius point count station with less bare ground and taller vegetation. Bare ground cover was lower on grazed plots, but vegetation was taller on ungrazed plots. Combined, our results suggest that low intensity grazing leads to grassland habitat change with both negative and positive effects on Vesper Sparrows and Western Meadowlarks, resulting in no net change in their broad-scale abundance.

  4. Climate change, land use and land surveyors

    NARCIS (Netherlands)

    van der Molen, P.; Mitchell, D.

    2016-01-01

    Research reveals that the land sector is a major emitter of greenhouse gases. But the land sector has also potential to reduce emissions. Different from other emission sectors like energy and transport, the land sector (in particular the rural area including forests) has the potential to also remove

  5. Ecological influence and pathways of land use in sagebrush

    Science.gov (United States)

    Knick, Steven T.; Hanser, Steven E.; Miller, Richard F.; Pyke, David A.; Wisdom, Michael J.; Finn, Sean P.; Rinkes, E. Thomas; Henny, Charles J.; Knick, Steven T.; Connelly, John W.

    2011-01-01

    Land use in sagebrush (Artemisia spp.) landscapes influences all sage-grouse (Centrocer-cus spp.) populations in western North America. Croplands and the network of irrigation canals cover 230,000 km2 and indirectly influence up to 77% of the Sage-Grouse Conservation Area and 73% of sagebrush land cover by subsidizing synanthropic predators on sage-grouse. Urbanization and the demands of human population growth have created an extensive network of con-necting infrastructure that is expanding its influence on sagebrush landscapes. Over 2,500 km2 are now covered by interstate highways and paved roads; when secondary roads are included, 15% of the Sage-Grouse Conservation Area and 5% of existing sagebrush habitats are 2.5 km from roads. Density of secondary roads often exceeds 5 km/km2, resulting in widespread motorized access for recreation, creating extensive travel corridors for management actions and resource development, subsidizing predators adapted to human presence, and facilitating spread of exotic or invasive plants. Sagebrush lands also are being used for their wilderness and recreation values, including off highway vehicle use. Approximately 12,000,000 animal use months (AUM amount of forage to support one livestock unit per month) are permitted for grazing livestock on public lands in the western states. Direct effects of grazing on sage-grouse populations or sagebrush landscapes are not possible to assess from current data. However, management of lands grazed by livestock has influenced sagebrush ecosystems by vegetation treatments to increase forage and reduce sagebrush and other plant species unpalatable to livestock. Fences (2 km/km2 in some regions), roads, and water developments to manage livestock movements further modify the landscape. Oil and gas development influences 8% of the sagebrush habitats with the highest intensities occurring in the eastern range of sage-grouse; 20% of the sagebrush distribution is indirectly influenced in the Great

  6. Application of MODIS Land Products to Assessment of Land Degradation of Alpine Rangeland in Northern India with Limited Ground-Based Information

    Directory of Open Access Journals (Sweden)

    Masahiro Tasumi

    2014-09-01

    Full Text Available Land degradation of alpine rangeland in Dachigam National Park, Northern India, was evaluated in this study using MODerate resolution Imaging Spectroradiometer (MODIS land products. The park has been used by a variety of livestock holders. With increasing numbers of livestock, the managers and users of the park are apprehensive about degradation of the grazing land. However, owing to weak infrastructure for scientific and statistical data collection and sociopolitical restrictions in the region, a lack of quality ground-based weather, vegetation, and livestock statistical data had prevented scientific assessment. Under these circumstances, the present study aimed to assess the rangeland environment and its degradation using MODIS vegetation, snow, and evapotranspiration products as primary input data for assessment. The result of the analysis indicated that soil water content and the timing of snowmelt play an important role in grass production in the area. Additionally, the possibility of land degradation in heavily-grazed rangeland was indicated via a multiple regression analysis at a decadal timescale, whereas weather conditions, such as rainfall and snow cover, primarily explained year-by-year differences in grass production. Although statistical uncertainties remain in the results derived in this study, the satellite-based data and the analyses will promote understanding of the rangeland environment and suggest the potential for unsustainable land management based on statistical probability. This study provides an important initial evaluation of alpine rangeland, for which ground-based information is limited.

  7. Effects of livestock species and stocking density on accretion rates in grazed salt marshes

    Science.gov (United States)

    Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

    2015-01-01

    Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management

  8. Biodiversity effects on ecosystem function due to land use: The case of buffel savannas in the Sky Islands Seas in the central region of Sonora

    Science.gov (United States)

    A. E. Castellanos; H. Celaya; C. Hinojo; A. Ibarra; J. R. Romo

    2013-01-01

    Buffel savannas have been an important landscape on cattle grazing ranches in Sonora over the past 50 years or more. Changes in land use result in biodiversity changes that may produce ecosystem functional changes; however, these are less well documented. Although fire driven processes have been proposed for Buffel savannas, this is not generally the case, and other...

  9. Identification of biomes affected by marginal expansion of agricultural land use induced by increased crop consumption

    DEFF Research Database (Denmark)

    Kløverpris, Jesper Hedal

    2009-01-01

    to characterise these areas. The present study ascribes so-called biomes (natural potential vegetation) to the areas affected by agricultural expansion in order to provide a basis for assessing the environmental impacts from land use in the life cycle impact assessment (LCIA). The methodology builds...... on agricultural statistics and maps of global agricultural areas and the global distribution of biomes. The application of the method is illustrated with four examples. The results indicate that agricultural expansion on land suited for crop cultivation (cultivable land) typically affects forest biomes...... or potential grassland/steppe, whereas expansion on land suited for grazing but not for crop cultivation (grazable land) typically occurs on potential shrubland or a few other biomes depending on the region. Some uncertainty applies to the results but it is concluded that it is feasible to identify biomes...

  10. Groundwater Ecosystems Vary with Land Use across a Mixed Agricultural Landscape.

    Science.gov (United States)

    Korbel, K L; Hancock, P J; Serov, P; Lim, R P; Hose, G C

    2013-01-01

    Changes in surface land use may threaten groundwater quality and ecosystem integrity, particularly in shallow aquifers where links between groundwater and surface activities are most intimate. In this study we examine the response of groundwater ecosystem to agricultural land uses in the shallow alluvial aquifer of the Gwydir River valley, New South Wales, Australia. We compared groundwater quality and microbial and stygofauna assemblages among sites under irrigated cropping, non-irrigated cropping and grazing land uses. Stygofauna abundance and richness was greatest at irrigated sites, with the composition of the assemblage suggestive of disturbance. Microbial assemblages and water quality also varied with land use. Our study demonstrates significant differences in the composition of groundwater ecosystems in areas with different surface land use, and highlights the utility of groundwater biota for biomonitoring, particularly in agricultural landscapes. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Exploring long-term trends in land use change and aboveground human appropriation of net primary production in nine European countries

    DEFF Research Database (Denmark)

    Gingrich, Simone; Niedertscheider, Maria; Kastner, Thomas

    2015-01-01

    Profound changes in land use occurred during the last century in Europe, driven by growing population, changes in affluence, and technological innovation. To capture and understand these changes, we compiled a consistent dataset on the distribution of land-use types and biomass extraction for nine...... primary production" (HANPP) framework for the nine countries and for the sum of all countries on a yearly basis from 1902 to 2003. We find that cropland and grazing land contracted in all countries except Albania in the observed period, while forestland increased. Crop yields increased in all countries......, most strongly during the second half of the 20th century. In some countries, biomass extraction on grazing lands increased to a similar extent. Overall, HANPP was high but declined slightly from 63% of the net primary production of potential vegetation in 1902 to 55% in 2003. This is the result...

  12. Milk from cows grazing on cool-season pastures provides an enhanced profile of bioactive fatty acids compared to those grazed on a monoculture of pearl millet.

    Science.gov (United States)

    Bainbridge, Melissa L; Egolf, Emily; Barlow, John W; Alvez, Juan P; Roman, Joe; Kraft, Jana

    2017-02-15

    The demand for dairy products from grass-fed cows is driven, in part, by their more desirable fatty acid (FA) profile, containing more n-3 FA and conjugated linoleic acids (CLA) than conventionally produced dairy products. This study investigated the effects of pearl millet (PM) vs. cool-season pasture (CSP) on animal performance and milk FA in a grazing system. Eight Holstein dairy cows were used in a repeated measures design with four-week periods. Forage type had no effect on animal performance (estimated dry matter intake, milk production, fat, or protein). The contents of CLA and n-3 FA in a serving of whole milk (3.25% fat) increased when cows grazed CSP compared to PM. A serving of whole milk from cows grazing PM had a higher content of saturated FA and branched-chain FA. In conclusion, the contents of various bioactive FA were higher in milk fat of cows grazing a CSP compared to PM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Dairy cows increase ingestive mastication and reduce ruminative chewing when grazing chicory and plantain.

    Science.gov (United States)

    Gregorini, P; Minnee, E M K; Griffiths, W; Lee, J M

    2013-01-01

    Although the nutritive value of chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) has been thoroughly studied, little is known about the grazing behavior of cattle feeding on chicory and plantain swards. The objective of the present study was to assess and describe the grazing behavior of dairy cows as affected by dietary proportions of chicory and plantain fed as monocultures for part of the day. Ninety Holstein-Friesian cows (489±42 kg of body weight; 4.1±0.3 body condition score, and 216±15 d in milk) were randomly assigned to 15 groups (6 cows per group) and grazed according to 7 treatments: control (CTL, 3 groups), perennial ryegrass (Lolium perenne L.) dominant sward (24-h pasture strip); 3 chicory treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of chicory to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment); and 3 plantain treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of plantain to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment). Four focal animals per group were equipped with 3-dimensional motion sensors, which provided the number of steps taken at each minute of the day. These cows were also fitted with automatic jaw-movement recorders that identified bites, mastication during ingestion, chewing during rumination, and determined grazing, rumination and idling times and bouts. Daily grazing time and bouts were not affected by treatments but rumination time differed and was reduced by up to 90 min when cows were allocated to chicory and plantain as 60% of their diet. Ruminative chewing was reduced in cows grazing chicory and plantain by up to 20% in cows allocated to the 60% treatments. Compared with perennial ryegrass, as the dietary proportion of chicory and plantain increased, cows spent more time idling and less time ruminating

  14. Human-induced climate change: the impact of land-use change

    Science.gov (United States)

    Gries, Thomas; Redlin, Margarete; Ugarte, Juliette Espinosa

    2018-02-01

    For hundreds of years, human activity has modified the planet's surface through land-use practices. Policies and decisions on how land is managed and land-use changes due to replacement of forests by agricultural cropping and grazing lands affect greenhouse gas emissions. Agricultural management and agroforestry and the resulting changes to the land surface alter the global carbon cycle as well as the Earth's surface albedo, both of which in turn change the Earth's radiation balance. This makes land-use change the second anthropogenic source of climate change after fossil fuel burning. However, the scientific research community has so far not been able to identify the direction and magnitude of the global impact of land-use change. This paper examines the effects of net carbon flux from land-use change on temperature by applying Granger causality and error correction models. The results reveal a significant positive long-run equilibrium relationship between land-use change and the temperature series as well as an opposing short-term effect such that land-use change tends to lead to global warming; however, a rise in temperature causes a decline in land-use change.

  15. Land use and second-generation biofuel feedstocks: The unconsidered impacts of Jatropha biodiesel in Rajasthan, India

    International Nuclear Information System (INIS)

    Findlater, K.M.; Kandlikar, M.

    2011-01-01

    Governments around the world see biofuels as a common solution to the multiple policy challenges posed by energy insecurity, climate change and falling farmer incomes. The Indian government has enthusiastically adopted a second-generation feedstock - the oilseed-bearing shrub, Jatropha curcas - for an ambitious national biodiesel program. Studies estimating the production capacity and potential land use implications of this program have typically assumed that the 'waste land' slated for Jatropha production has no economic value and that no activities of note will be displaced by plantation development. Here we examine the specific local impacts of rapid Jatropha plantation development on rural livelihoods and land use in Rajasthan, India. We find that in Jhadol Tehsil, Jatropha is planted on both government and private land, and has typically displaced grazing and forage collection. For those at the socioeconomic margins, these unconsidered impacts counteract the very benefits that the biofuel programs aim to create. The Rajasthan case demonstrates that local land-use impacts need to be integrated into decision-making for national targets and global biofuel promotion efforts. - Highlights: → Hardy biofuel crops like Jatropha replace edible feedstocks that use arable land. → In Rajasthan, Jatropha displaces grazing and forage on both public and private land. → As Jatropha plantations mature, the loss of grass becomes more pronounced. → Unconsidered impacts negate the benefits that the biodiesel program aims to create. → Local land-use impacts need to be integrated into decision-making.

  16. Land use and second-generation biofuel feedstocks: The unconsidered impacts of Jatropha biodiesel in Rajasthan, India

    Energy Technology Data Exchange (ETDEWEB)

    Findlater, K.M. [Institute for Resources Environment and Sustainability, University of British Columbia, 429-2202 Main Mall, Vancouver, BC, V6T1Z4 (Canada); Kandlikar, M., E-mail: milind.k@ubc.ca [Liu Institute for Global Studies, University of British Columbia, 6476 NW Marine Drive, Vancouver, BC, V6T1Z2 (Canada)

    2011-06-15

    Governments around the world see biofuels as a common solution to the multiple policy challenges posed by energy insecurity, climate change and falling farmer incomes. The Indian government has enthusiastically adopted a second-generation feedstock - the oilseed-bearing shrub, Jatropha curcas - for an ambitious national biodiesel program. Studies estimating the production capacity and potential land use implications of this program have typically assumed that the 'waste land' slated for Jatropha production has no economic value and that no activities of note will be displaced by plantation development. Here we examine the specific local impacts of rapid Jatropha plantation development on rural livelihoods and land use in Rajasthan, India. We find that in Jhadol Tehsil, Jatropha is planted on both government and private land, and has typically displaced grazing and forage collection. For those at the socioeconomic margins, these unconsidered impacts counteract the very benefits that the biofuel programs aim to create. The Rajasthan case demonstrates that local land-use impacts need to be integrated into decision-making for national targets and global biofuel promotion efforts. - Highlights: > Hardy biofuel crops like Jatropha replace edible feedstocks that use arable land. > In Rajasthan, Jatropha displaces grazing and forage on both public and private land. > As Jatropha plantations mature, the loss of grass becomes more pronounced. > Unconsidered impacts negate the benefits that the biodiesel program aims to create. > Local land-use impacts need to be integrated into decision-making.

  17. Radionuclides in sheep grazing near old uranium mines

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Fernando P.; Oliveira, Joao M.; Malta, M. [Instituto Superior Tecnico/Campus Tecnologico e Nuclear/ (IST/CTN), Universidade de Lisboa, Estrada Nacional 10 - ao km 139,7, - 2695-066 Bobadela LRS (Portugal); Lemos, M.E. [Servicos de Alimentacao e Veterinaria da Regiao Centro, Bairro Na Sra dos Remedios, 6300 Guarda (Portugal); Vala, H.; Esteves, F. [Escola Superior Agraria de Viseu, Quinta da Alagoa, Estrada de Nelas, Ranhados,3500-606 Viseu (Portugal)

    2014-07-01

    During the past century extensive uranium mining took place in Portugal for radium and uranium production. Many uranium deposits were mined as open pits and after ore extraction and transportation to milling facilities, mining wastes were left on site. One uranium ore mining site, Boco Mine, was extracted in the 1960's and 70's and mining waste and open pits were left uncovered and non-remediated since closure of uranium mining activities. During the nineties a quarry for sand extraction was operated in the same site and water from a local stream was extensively used in sand sieving. Downstream the mine areas, agriculture soils along the water course are currently used for cattle grazing. Water from this stream, and water wells, soil, pasture and sheep meat were analyzed for radionuclides of the uranium series. The U- series radionuclide {sup 226}Ra was generally the highest in concentrations especially in soil, pasture, and in internal organs of sheep. Ra-226 concentrations averaged 1093±96 Bq/kg (dry weight) in soil, 43±3 Bq/kg (dw) in pasture, and 0.76±0.41 Bq/kg (dw) in muscle tissue of sheep grown there. Other sheep internal organs displayed much higher {sup 226}Ra concentrations, such as the brain and kidneys with 7.7±2.3 Bq/kg (dw) and 28±29 Bq/kg (dw), respectively. Results of tissue sample analysis for sheep grown in a comparison area were 2 to 11 times lower, depending on the tissue. Absorbed radiation doses for internal organs of sheep were computed and may exceed 20 mSv/y in the kidney. Although elevated, this absorbed radiation dose still is below the threshold for biological effects on mammals. Nevertheless, enhanced environmental radioactive contamination mainly due to radium was observed in the area of influence of this legacy uranium mine and there is potential food chain transfer for humans (authors)

  18. Mingled Mortality: the Interplay Between Protist Grazing and Viral Lysis on Emiliania huxleyi Cell Fate

    Science.gov (United States)

    Harvey, E.; Bidle, K. D.; Johnson, M. D.

    2016-02-01

    The coccolithophore, Emiliania huxleyi plays a prominent role in global carbon cycling, as their calcite coccoliths account for a third of all oceanic calcite production. Mortality due to grazing by microzooplankton is the largest contributor to phytoplankton loss in the marine environment. However, viral infection of E. huxleyi is now thought to be as important as grazing pressure in contributing to its mortality. To understand the influence of viral infection on grazing dynamics, we examined the response of the dinoflagellate predator, Oxyrrhis marina to E. huxleyi infected with four different strains of the E. huxleyi virus (EhV). Grazing rate was significantly slower on E. huxleyi cultures that had been infected for 48 h compared to an uninfected control and this reduction in grazing rate was dependent on the strain identity of infecting EhVs. Additional experimentation indicated that grazing was the primary source of E. huxleyi loss ( 78-98%) during the first 24 h of exposure to both predator and virus. However, as viral infection progressed into the late lytic phase (48 h hour post infection), the relative contribution of grazing to total E. huxleyi mortality decreased ( 5-60%). These results suggest that mortality is partitioned along a gradient between predator-based consumption and virus-induced cell lysis, dependent on the timing of infection. Deciphering the relative importance and interactive nature of these alga-predator-viral interactions will help to elucidate the mechanisms that drive bulk measurements of phytoplankton loss, a necessary understanding to interpret and predict phytoplankton population dynamics and associated biogeochemical cycling.

  19. Effect of day or night grazing on behaviour of swamp buffalo heifers

    Directory of Open Access Journals (Sweden)

    Somparn, P.

    2007-03-01

    Full Text Available An experiment was conducted to examine the effect of day or night grazing on behaviour by swamp buffaloes. A grazing trial was conducted over 42 days in the late rainy season, during September to November2005 at Surin Livestock Research and Breeding Center, Surin province. The experimental period was divided into two 21-day periods. Twelve 2-year-old swamp buffalo heifers were allocated to four groups, eachcontaining three heifers, with the mean group weights being as similar as possible. Each group was allowed to graze either from 06:20 to 18:00 h (daytime treatment or from 18:20 to 06:00 h (nighttime treatment infour separate paddocks, each of 5 rai, using a cross-over design. When not at pasture the animals in each group were kept in the common corral with free access to fresh drinking water and mineral blocks. Individualanimal activity was recorded by visual observation at 1-min intervals during the period at pasture. Individual groups within each period were treated as replicates. Differences between group means weretested using MIXED procedure of SAS.The buffaloes on daytime treatment spent longer (P<0.05 grazing than those on nighttime treatment (423 vs 332 min. The number of meals differed (P<0.05 between treatments, but overall mean meal durationswere similar (73 min. Buffaloes allowed to graze during daylight had a tendency (P<0.10 toward a higher bite and step rates than those grazing during the night. With the reduction in grazing activity duringthe night on nighttime treatment, the animals ruminated for longer during the period at pasture (327 and 191 min, P<0.001. Live-weight change over periods of 20 days did not differ significantly. The difference intemporal behaviour patterns between treatments indicated that animals have to adapt foraging strategies appropriate for different situations in order to maintain feed intake and subsequently production.

  20. Strategic grazing management towards sustainable intensification at tropical pasture-based dairy systems.

    Science.gov (United States)

    Congio, Guilhermo F S; Batalha, Camila D A; Chiavegato, Marília B; Berndt, Alexandre; Oliveira, Patrícia P A; Frighetto, Rosa T S; Maxwell, Thomas M R; Gregorini, Pablo; Da Silva, Sila C

    2018-05-01

    Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI 95% and LI Max , respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH 4 ) emissions by Holstein × Jersey dairy cows. We hypothesized that grazing strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH 4 emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LI Max (≈135 cm) than LI 95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on LI 95% criteria improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH 4 emission was not affected; however, cows grazing elephant grass at LI 95% were more efficient and emitted 21% less CH 4 /kg of milk yield and 18% less CH 4 /kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH 4 emissions per hectare in LI 95% grazing management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic grazing management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Rotational Grazing System for Beef Cows on Dwarf Elephantgrass Pasture for Two Years after Establishment

    Directory of Open Access Journals (Sweden)

    M Mukhtar

    2011-01-01

    Full Text Available An intensive rotational grazing system for dwarf and late heading (DL elephant grass (Pennisetum purpureum Schumach pasture was examined in a summer period for two years following establishment. Four 0.05 of DL elephant grass pastures (20×25 m were established on May 2003. They were rotationally grazed for 1 week, followed by a 3-week rest period by three breeding or raising beef cattle for three and six cycles during the first and second years of establishment respectively. Before grazing, the plant height, leaf area index and the ratio of leaf blade to stem were at the highest, while tiller number increased and herbage mass tended to increase, except for the first grazing cycle both two years and for one paddock in the second year. Herbage consumption, the rate of herbage consumption and dry matter intake tended to decrease in three paddocks from the first to the third cycle in the first year, but increase as grazing occurred in the second year. Dry matter intake averaged 10.2-14.5 and 15.4–23.2 g DM/kg/live weight (LW/day over the four paddocks in the first and second year, respectively, and average daily gains were 0.09 and 0.35 kg/head/day in the first and second year respectively. The carrying capacities were estimated at 1,016 and 208 cow-days (CD/ha (annual total 1,224 CD/ha in the first year and 1,355 and 207 CD/ha (annual total 1,562 CD/ha in the second year. Thus, DL elephant grass pasture can expand the grazing period for beef cows for the following two-year establishment. (Animal Production 13(1:10-17 (2011 Key Words: dwarf elephant grass, herbage mass, plant characters, rotational grazing

  2. Interactions of Grazing History, Cattle Removal and Time since Rain Drive Divergent Short-Term Responses by Desert Biota

    Science.gov (United States)

    Frank, Anke S. K.; Dickman, Chris R.; Wardle, Glenda M.; Greenville, Aaron C.

    2013-01-01

    Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota

  3. A comparison of some methods used to estimate the grazing capacity of a game ranch in Northern Province, South Africa

    Directory of Open Access Journals (Sweden)

    A.G. Schmidt

    1995-08-01

    Full Text Available The grazing capacity of a game ranch in Northern Province was estimated in a number of different ways using rainfall and herbaceous composition and phytomass data. The results indicate that the grazing capacity under the present environmental conditions should be approximately 50 of the recommended agricultural grazer stocking rate. This is in agreement with recent literature, indicating that the methods used should be suitable for determining a first approximation of grazing capacity in the mixed bushveld of Northern Province.

  4. National-Scale Changes in Soil Profile C and N in New Zealand Pastures are Determined by Land Use

    Science.gov (United States)

    Schipper, L. A.; Parfitt, R.; Ross, C.; Baisden, W. T.; Claydon, J.; Fraser, S.

    2010-12-01

    Grazed pasture is New Zealand’s predominant agricultural land-use and has been relatively recently developed from forest and native grasslands/shrub communities. From the 1850s onwards, land was cleared and exotic pastures established. Phosphorus fertilizer was increasingly used after 1950 which accelerated N fixation by clover. In the last two decades N fertilizers have been used, and grazing intensity has increased, thus affecting soil C and N. Re-sampling of 31 New Zealand soil profiles under grazed pasture measured surprisingly large losses of C and N over the last 2-3 decades (Schipper et al., 2007 Global Change Biology 13:1138-1144). These profiles were predominantly on the most intensively grazed flat land. We extended this re-sampling to 83 profiles (to 90 cm depth), to investigate whether changes in soil C and N stocks also occurred in less intensively managed pasture. Archived soils samples were analysed for total soil C and N alongside the newly collected samples. Intact cores were collected to determine bulk density through the profile. Over an average of 27 years, soils (0-30 cm) in flat dairy pastures significantly lost 0.73±0.16 Mg C ha-1y-1 and 57±16 kg N ha-1y-1 while we observed no change in soil C or N in flat pasture grazed by “dry stock” (e.g., sheep, beef), or in grazed tussock grasslands. Grazed hill country soils (0-30 cm) gained 0.52±0.18 Mg C ha-1y-1 and 66±18 kg N ha-1y-1. The losses of C and N were strongly correlated and C:N ratio has generally declined suggesting soils are becoming N saturated. Losses and gains also occurred in soil layers below 30 cm demonstrating that organic matter throughout the profile was responding to land use. The losses under dairying may be due to greater grazing pressure, fertilizer inputs and exports of C and N. There is evidence that grazing pressure reduces inputs of C below ground, reduces soil microbial C, and that dairy cow urine can mobilise C and N. Gains in hill country pastures may be due

  5. Investigations on the effect of grazing intensity on the transfer of radionuclides to cow`s milk

    Energy Technology Data Exchange (ETDEWEB)

    Voigt, G. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Schotola, C. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Crout, N.M.J. [Nottingham Univ. (United Kingdom). Dept. of Physiology and Environmental Science; Absalom, J. [Nottingham Univ. (United Kingdom). Dept. of Physiology and Environmental Science

    1997-03-01

    For these investigations two farms were chosen. Farm A carries out a rotational grazing regime with 4 grazed pastures which is the more commonly used farm practice in Bavaria, farm B practises a continuous grazing regime with one grazed pasture only. In farm B a tenfold lower Cs-137 activity concentration was observed in milk though activity concentrations in soil and pasture grass were the same as that at farm A, indicating the same transfer rate soil-plant at both locations. It could be shown under normal agricultural conditions that with a higher grazing pressure lower activity concentrations in milk (in this case a factor of about 2 to 3) were obtained. Therefore changing stock density in combination with a continuous grazing regime on a given pasture after a major nuclear accident can be considered as a possible countermeasure which can be easily applied. Mainly to get more synchronised growth rates and a homogeneous distribution of radiocontamination plot experiments were performed to simulate the influence of grazing intensity. Under the experimental design used here no effect of grazing intensity on the transfer of radionuclides to vegetation could be found. Effects of grazing intensity as found for the farm experiment, therefore must be due to other sources than vegetation activities, and are presumably due to soil ingestion preventing uptake of soluble plant incorporated radiocaesium in the animal rumen. (orig./MG)

  6. Non-bleached colonies of massive Porites may attract fishes for selective grazing during mass bleaching events

    Directory of Open Access Journals (Sweden)

    Eri Ikeuchi

    2017-06-01

    Full Text Available In this study we investigated the variation in grazing scar densities between bleached and non-bleached colonies of massive Porites species in Sekisei Lagoon (Okinawa, southwestern Japan during a mass bleaching event in 2016. The grazing scar densities and bleaching susceptibility varied among neighboring colonies of massive Porites spp. However, non-bleached colonies had significantly more surface scars than bleached colonies. One explanation for these variations is that corallivorous fishes may selectively graze on non-bleached, thermally tolerant colonies. This is the first report of a relationship between grazing scars and the bleaching status of massive Porites spp. colonies during a mass bleaching event.

  7. 78 FR 66064 - Notice of Intent To Prepare a Livestock Grazing Monument Management Plan Amendment and Associated...

    Science.gov (United States)

    2013-11-04

    ...-level decisions associated with livestock grazing, thereby amending the GSENM Management Plan. DATES..., archaeology, paleontology, wildlife and fisheries, hydrology, soils, sociology and economics, and public...

  8. Understanding land administration systems

    DEFF Research Database (Denmark)

    P. Williamson, Ian; Enemark, Stig; Wallace, Judy

    2008-01-01

    This paper introduces basic land administration theory and highlights four key concepts that are fundamental to understanding modern land administration systems - firstly the land management paradigm and its influence on the land administration framework, secondly the role that the cadastre plays...... in contributing to sustainable development, thirdly the changing nature of ownership and the role of land markets, and lastly a land management vision that promotes land administration in support of sustainable development and spatial enablement of society. We present here the first part of the paper. The second...

  9. Advances in monitoring vegetation and land use dynamics in the Sahel

    DEFF Research Database (Denmark)

    Mbow, Cheikh; Fensholt, Rasmus; Nielsen, Thomas Theis

    2014-01-01

    of CO2 in the atmosphere, grazing pressure, bush fires and agricultural expansion or contraction. The use of satellite data in combination with field data played a major role in the monitoring of vegetation dynamics and land use in the Sahel, since the mega drought of the 1970s and the 1980s. This paper...... briefly reviews the advance of satellite-based monitoring of vegetation dynamics over these 40 years. We discuss the promises of current and likely future data sources and analysis tools, as well as the need to strengthen in situ data collection to support and validate satellite-based vegetation and land...

  10. Effects of previous grazing nutrition and management on feedlot performance of cattle.

    Science.gov (United States)

    Drouillard, J S; Kuhl, G L

    1999-01-01

    Management strategies designed to improve grazing animal performance can influence feedlot performance and carcass traits both positively and negatively. In spite of the economic relevance of potential interactions between grazing and finishing performance, controlled experiments evaluating integrated production systems are limited in number. Effects of grazing treatments can result from, or be overshadowed by, changes in gut fill, thus making it difficult to assign precise costs to different phases of production. Published reports have considered the effects of stocking rate, duration of grazing, forage characteristics, supplementation, and growth-promoting implants on subsequent finishing performance. Improvements in cattle performance attributed to changes in stocking rate generally have been neutral to positive with respect to effects on finishing performance. Comparisons among forages have led to the suggestion that forage species may contribute to differences in gastrointestinal fill of grazing cattle, thereby influencing gain and efficiency during the subsequent finishing phase. Creep-feeding suckling calves generally has increased preweaning performance but has had relatively little influence on performance during the subsequent finishing phase. Grain supplementation of stocker cattle during the grazing period has improved grazing performance, but effects on subsequent feedlot performance have been inconsistent. Potential carryover effects from protein and mineral supplementation also have been inconclusive. Lack of congruence among studies is puzzling but may be the consequence of highly varied production systems, differences in experimental procedures, and changes in gut fill or mass of internal organs. Based on the studies reviewed, the expression or absence of compensatory growth during the finishing phase appears to be related to the nutritional quality of forages utilized in the grazing period, with higher quality forages tending to yield greater

  11. Sentinel model for influenza A virus monitoring in free-grazing ducks in Thailand.

    Science.gov (United States)

    Boonyapisitsopa, Supanat; Chaiyawong, Supassama; Nonthabenjawan, Nutthawan; Jairak, Waleemas; Prakairungnamthip, Duangduean; Bunpapong, Napawan; Amonsin, Alongkorn

    2016-01-01

    Influenza A virus (IAV) can cause influenza in birds and mammals. In Thailand, free-grazing ducks are known IAV reservoirs and can spread viruses through frequent movements in habitats they share with wild birds. In this study, the sentinel model for IAV monitoring was conducted over 4 months in two free-grazing duck flocks. IAV subtypes H4N6 (n=1) and H3N8 (n=5) were isolated from sentinel ducks at the ages of 13 and 15 weeks. Clinical signs of depression and ocular discharge were observed in the infected ducks. Phylogenetic analysis and genetic characterization of the isolated IAVs indicated that all Thai IAVs were clustered in the Eurasian lineage and pose low pathogenic avian influenza characteristics. Serological analysis found that antibodies against IAVs could be detected in the ducks since 9-weeks-old. In summary, our results indicate that the sentinel model can be used for IAV monitoring in free-grazing duck flocks. Since free-grazing ducks are potential reservoirs and transmitters of IAVs, routine IAV surveillance in free-grazing duck flocks can be beneficial for influenza prevention and control strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. CHANGES IN THE MORPHOLOGY AND POLYSACCHARIDE CONTENT OF MICROCYSTIS AERUGINOSA (CYANOBACTERIA) DURING FLAGELLATE GRAZING(1).

    Science.gov (United States)

    Yang, Zhou; Kong, Fanxiang; Shi, Xiaoli; Zhang, Min; Xing, Peng; Cao, Huansheng

    2008-06-01

    To investigate the changes in the morphology and polysaccharide content of Microcystis aeruginosa (Kütz.) Kütz. during flagellate grazing, cultures of M. aeruginosa were exposed to grazing Ochromonas sp. for a period of 9 d under controlled laboratory conditions. M. aeruginosa responded actively to flagellate grazing and formed colonies, most of which were made up of several or dozens of cells, suggesting that flagellate grazing may be one of the biotic factors responsible for colony formation in M. aeruginosa. When colonies were formed, the cell surface ultrastructure changed, and the polysaccharide layer on the surface of the cell wall became thicker. This change indicated that synthesis and secretion of extracellular polysaccharide (EPS) of M. aeruginosa cells increased under flagellate grazing pressure. The contents of soluble extracellular polysaccharide (sEPS), bound extracellular polysaccharide (bEPS), and total polysaccharide (TPS) in colonial cells of M. aeruginosa increased significantly compared with those in single cells. This finding suggested that the increased amount of EPS on the cell surface may play a role in keeping M. aeruginosa cells together to form colonies. © 2008 Phycological Society of America.

  13. Using Ecophysiology to Improve Farm Efficiency: Application in Temperate Dairy Grazing Systems

    Directory of Open Access Journals (Sweden)

    David F. Chapman

    2016-04-01

    Full Text Available Information on the physiological ecology of grass-dominant pastures has made a substantial contribution to the development of practices that optimise the amount of feed harvested by grazing animals in temperate livestock systems. However, the contribution of ecophysiology is often under-stated, and the need for further research in this field is sometimes questioned. The challenge for ecophysiolgists, therefore, is to demonstrate how ecophysiological knowledge can help solve significant problems looming for grassland farming in temperate regions while also removing constraints to improved productivity from grazed pastures. To do this, ecophysiological research needs to align more closely with related disciplines, particularly genetics/genomics, agronomy, and farming systems, including systems modelling. This review considers how ecophysiological information has contributed to the development of grazing management practices in the New Zealand dairy industry, an industry that is generally regarded as a world leader in the efficiency with which pasture is grown and utilised for animal production. Even so, there are clear opportunities for further gains in pasture utilisation through the refinement of grazing management practices and the harnessing of those practices to improved pasture plant cultivars with phenotypes that facilitate greater grazing efficiency. Meanwhile, sub-optimal persistence of new pastures continues to constrain productivity in some environments. The underlying plant and population processes associated with this have not been clearly defined. Ecophysiological information, placed in the context of trait identification, grounded in well-designed agronomic studies and linked to plant improvements programmes, is required to address this.

  14. STRUCTURE AND NUTRITIVE VALUE OF DEFERRED PASTURE OF BRACHIARIA DECUMBENS CV. BASILISK DURING THE GRAZING PERIOD

    Directory of Open Access Journals (Sweden)

    Manoel Eduardo Rozalino Santos

    2011-07-01

    Full Text Available The experiment aimed to understand the effect of grazing period on morphology and nutritive value of deferred Brachiaria decumbens cv. Basilisk pasture and on hand-plucking sample with cattle. Subdivided plots were used according to a randomized block design with two replicates. Four grazing periods (1, 31, 57 and 88 days and two forage samples (available in pasture (AP and obtained by hand-plucking (HP were studied. The live leaf laminae (LLL, potentially digestible neutral detergent fiber (PDNDF, potentially digestible dry matter (PDDM and crude protein (CP levels were higher and dead leaf laminae (DLL, and dead stem (DS, neutral detergent fiber (NDF and indigestible NDF percentages were lower in sample of HP in relation to forage AP. The grazing period decreased linearly the LLL, PDNDF, PDDM percentages, as well as increased linearly DS and indigestible NDF levels in forages. The potential selectivity indexes (PSI of LLL and indigestible NDF increased linearly with grazing period. The PSI of live stem was smaller and the PSI of CP was higher in interim periods of grazing. The reduction in deferring period results in B. decumbens with better morphological composition and nutritional value, which favors the animal selectivity.

  15. Grazing effects on ecosystem CO2 fluxes differ among temperate steppe types in Eurasia.

    Science.gov (United States)

    Hou, Longyu; Liu, Yan; Du, Jiancai; Wang, Mingya; Wang, Hui; Mao, Peisheng

    2016-07-01

    Grassland ecosystems play a critical role in regulating CO2 fluxes into and out of the Earth's surface. Whereas previous studies have often addressed single fluxes of CO2 separately, few have addressed the relation among and controls of multiple CO2 sub-fluxes simultaneously. In this study, we examined the relation among and controls of individual CO2 fluxes (i.e., GEP, NEP, SR, ER, CR) in three contrasting temperate steppes of north China, as affected by livestock grazing. Our findings show that climatic controls of the seasonal patterns in CO2 fluxes were both individual flux- and steppe type-specific, with significant grazing impacts observed for canopy respiration only. In contrast, climatic controls of the annual patterns were only individual flux-specific, with minor grazing impacts on the individual fluxes. Grazing significantly reduced the mean annual soil respiration rate in the typical and desert steppes, but significantly enhanced both soil and canopy respiration in the meadow steppe. Our study suggests that a reassessment of the role of livestock grazing in regulating GHG exchanges is imperative in future studies.

  16. Re-visiting the nutrition of dairy sheep grazing Mediterranean pastures

    Directory of Open Access Journals (Sweden)

    M. Decandia

    2010-04-01

    Full Text Available In the light of recent findings in sheep nutrition and behaviour, the diets of grazing dairy sheep should be based on forages encompassing a variety of complementary nutritional values and containing moderate levels of complementary plant secondary metabolites, until recently regarded as "anti-nutritional". In lactating sheep, pastures of tannin-containing legumes like sulla (Hedysarum coronarium and chicory (Cichorium intybus can be integrated with annual grasses for establishing sustainable artificial pastures under rainfed conditions. Diets based on these forages, while ensuring high milking performance, can mitigate the unbalance of CP to energy ratio of grazing sheep. By grazing sulla and annual or Italian ryegrass (50:50 by area as spatially conterminal monocultures or in timely sequence (complementary grazing sheep eat more and perform better than by grazing the ryegrass pasture only. Concentrate supplementation of lactating sheep should be preferably based on fibrous sources (soyhulls or beet pulps, particularly from mid-lactation onwards and when supplementation levels are high. Milk urea concentration is confirmedly a useful monitoring tool to balance protein nutrition and curb the waste of N at animal and system level.

  17. The role of grazing in nutrient-rich areas of the open sea

    International Nuclear Information System (INIS)

    Frost, B.W.

    1991-01-01

    No single factor accounts fully for the persistently low phytoplankton stocks in the nutrient-rich areas of the open sea. However, grazing plays the necessary role of consuming phytoplankton produced in excess of losses due to physical processes and sinking. Without grazing, even if specific growth rate of the phytoplankton is less than optimal for the prevailing light and temperature conditions, as might be so under limitation by a trace nutrient such as Fe, the phytoplankton stock would still accumulate with attendant depletion of nutrients. Observations during spring and summer in the open subarctic Pacific argue against limitation of phytoplankton growth to the point where phytoplankton stock could not increase in the absence of grazing. An ecosystem process model of the phytoplankton-grazer interaction suggests that two processes - grazing control of phytoplankton stock and preferential utilization of NH 4 by the phytoplankton - are sufficient to explain the continuously low phytoplankton stock and high concentrations of macronutrients. However, the grazing control may be exerted on a phytoplankton assemblage structured by Fe limitation. In particular, the intrinsic growth rates of potentially fast-growing diatoms seem to be depressed in the open subarctic Pacific. These conditions probably apply to two other nutrient-rich areas of the open sea, the Pacific equatorial upwelling region and the subantarctic circumpolar ocean, although in the latter region light limitation of phytoplankton growth may be more severe and silica limitation may influence the specific composition of the phytoplankton assemblage

  18. Short-term spider community monitoring after cattle removal in grazed grassland

    Directory of Open Access Journals (Sweden)

    Guilherme O. da Silva

    2017-10-01

    Full Text Available ABSTRACT. At the Pampa Biome, grazing, like others disturbances, affects fauna and flora, creating heterogeneity in the environment. Little is known about how the diversity and richness of arthropods change during this impact. To improve the knowledge of how spider diversity is affected by grazing, experiments were realized at Pampa. The hypothesis is that abundance of spider will be different when comparing grazed and ungrazed areas. A paired block, with two areas of one hectare each, was established in three areas in the Environmental Protection Area of Ibirapuitã (APA Ibirapuitã, state of Rio Grande do Sul, Brazil. One of these hectares was closed with fences, excluding the catle grazing, in August of 2012. Samplings were realized in November of 2011, 2012 and 2013 using Pitfall traps filled with formol 4% and disposed in an “X” format in each area. For statistical analyses, T test, ANOSIM, ANOVA and Rarefaction were performed. A total of 1,315 spiders were captured, comprising 77 species or morphospecies belonging to 20 families. The family most abundant was Lycosidae followed by Hahniidae, Linyphiidae and Theridiidae. Linyphiidae was the richest family with 14 species or morphospecies identified. All spiders, adults and juveniles, only adults in species and morphospecies, and most abundant species were used as models for statistics. These models revealed no significant difference between grazed and ungrazed areas after three and 15 months of cattle exclusion.

  19. Morphological Responses Explain Tolerance of the Bamboo Yushania microphylla to Grazing

    Directory of Open Access Journals (Sweden)

    Kesang Wangchuk

    2014-01-01

    Full Text Available Mechanisms of tolerance of the bamboo Y. microphylla to ungulate herbivory were investigated by measuring above- and belowground morphogenetic traits and biomass allocation patterns of the bamboo Y. microphylla under grazed and ungrazed conditions in a Himalayan mixed conifer forest. Data were collected from 5 populations consisting of 10 ramets each in adjacent grazed and ungrazed plots. Compared with ungrazed ramets, the aboveground morphological modifications of grazed ramets were higher culm density, shorter and thinner culms, shorter internode, and shorter top leaf. The belowground morphological modifications for the grazed ramets were thinner rhizomes, lower rhizome biomass and dry matter, more nodes, and shorter internodes. Despite the lower biomass and dry matter, the root-to-shoot ratio was higher for grazed ramets. Results suggest that Y. microphylla subjected to herbivory shows aboveground overcompensation in terms of densification at the cost of belowground biomass, but at the same time maintains a higher proportion of belowground reserves, as compared to ungrazed conditions. These responses provide adequate evidence to conclude that Y. microphylla tolerates ungulate herbivory through above- and belowground morphological modifications.

  20. Land Competition and Land-Use Change:

    DEFF Research Database (Denmark)

    Vongvisouk, Thoumthone

    Land competition and land-use changes are taking place in many developing countries as the demand for land increases. These changes are leading to changes in the livelihood conditions of rural people. The Government of Laos (GoL), on the one hand, aims to increase forest protection. On the other...... hand, the government is also working to increase national economic growth by promoting private-sector investment in both agriculture and forest resources – two sectors that compete for the same areas intended for protection. This thesis explores how these contradictory drivers of land-use changes...... software. Quantitative data was compiled in a Microsoft Access database and analyzed in Excel. Land-use and livelihood changes are taking place rapidly in the study sites. Overall, land-use change underwent transformation away from subsistence shifting cultivation to cash crops, intensive agriculture...

  1. Earth land landing alternatives: Lunar transportation system

    Science.gov (United States)

    Meyerson, Robert

    1992-01-01

    The objectives of this study are as follows: (1) develop a landing option such that it is a viable trade option for future NASA missions; (2) provide NASA programs with solid technical support in the landing systems area; (3) develop the technical staff; and (4) advance the state of landing systems technology to apply to future NASA missions. All results are presented in viewgraph format.

  2. Models meet data: Challenges and opportunities in implementing land management in Earth system models.

    Science.gov (United States)

    Pongratz, Julia; Dolman, Han; Don, Axel; Erb, Karl-Heinz; Fuchs, Richard; Herold, Martin; Jones, Chris; Kuemmerle, Tobias; Luyssaert, Sebastiaan; Meyfroidt, Patrick; Naudts, Kim

    2018-04-01

    As the applications of Earth system models (ESMs) move from general climate projections toward questions of mitigation and adaptation, the inclusion of land management practices in these models becomes crucial. We carried out a survey among modeling groups to show an evolution from models able only to deal with land-cover change to more sophisticated approaches that allow also for the partial integration of land management changes. For the longer term a comprehensive land management representation can be anticipated for all major models. To guide the prioritization of implementation, we evaluate ten land management practices-forestry harvest, tree species selection, grazing and mowing harvest, crop harvest, crop species selection, irrigation, wetland drainage, fertilization, tillage, and fire-for (1) their importance on the Earth system, (2) the possibility of implementing them in state-of-the-art ESMs, and (3) availability of required input data. Matching these criteria, we identify "low-hanging fruits" for the inclusion in ESMs, such as basic implementations of crop and forestry harvest and fertilization. We also identify research requirements for specific communities to address the remaining land management practices. Data availability severely hampers modeling the most extensive land management practice, grazing and mowing harvest, and is a limiting factor for a comprehensive implementation of most other practices. Inadequate process understanding hampers even a basic assessment of crop species selection and tillage effects. The need for multiple advanced model structures will be the challenge for a comprehensive implementation of most practices but considerable synergy can be gained using the same structures for different practices. A continuous and closer collaboration of the modeling, Earth observation, and land system science communities is thus required to achieve the inclusion of land management in ESMs. © 2017 John Wiley & Sons Ltd.

  3. Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands.

    Science.gov (United States)

    Howland, Brett; Stojanovic, Dejan; Gordon, Iain J; Manning, Adrian D; Fletcher, Don; Lindenmayer, David B

    2014-01-01

    Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.

  4. Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands.

    Directory of Open Access Journals (Sweden)

    Brett Howland

    Full Text Available Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1 density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2 grass structure and reptiles (i.e. abundance, richness, diversity and occurrence across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.

  5. Successive sheep grazing reduces population density of Brandt's voles in steppe grassland by altering food resources: a large manipulative experiment.

    Science.gov (United States)

    Li, Guoliang; Yin, Baofa; Wan, Xinrong; Wei, Wanhong; Wang, Guiming; Krebs, Charles J; Zhang, Zhibin

    2016-01-01

    Livestock grazing has shaped grassland ecosystems around the world. Previous studies indicated grazing showed various impacts on small rodents; however, most studies were conducted over 1-2 years without controlling for confounding factors such as immigration/emigration and predation in rodents. Brandt's voles (Lasiopodomys brandtii) are generally recognized as pests because of food overlap with domestic herbivores, but are also important for biodiversity conservation because they provide nests or food to many birds. Fully understanding the ecological relationship between domestic herbivores and small mammals is essential to making ecosystem management decisions. To address these needs, we carried out a field experiment during the period 2010-2013 to assess the effects of sheep grazing on vegetation and the population density of Brandt's voles along a gradient of three grazing intensities by using 12 large-scale enclosures. Responses of Brandt's voles to livestock grazing varied with grazing intensity and year. As compared to the control group, sheep grazing had no effect on vole abundance in the first year but an overall negative effect on vole abundance in the following 3 years. Successive grazing caused decreases in survival and male body mass of voles, but had no significant effect on fecundity. Negative effects of grazing were associated with a grazing-induced deterioration in both food quantity (reflected by biomass and cover of less-preferred plants), and food quality (measured by tannin and total phenol content). Our findings highlight the urgent need for more flexible management of yearly rotational grazing to optimize livestock production while maintaining species diversity and ecosystem health.

  6. Release and Consumption of DMSP from Emiliania Huxleyi during grazing by Oxyrrhis Marina

    Science.gov (United States)

    Wolfe, Gordon V.; Sherr, Evelyn B.; Sherr, Barry F.

    1994-01-01

    Degradation and release to solution of intracellular dimethylsulfoniopropionate (DMSP) from Emiliania huxleyi 370 was observed during grazing by the heterotrophic dinoflagellate Oxyrrhis marina in 24 h bottle incubations. Between 30 and 70% of the lost algal DMSP was metabolized by the grazers without production of dimethylsulfide (DMS) when grazer densities were 150 to 450/ml. The rest was released to solution and about 30% was converted to DMS by bacteria associated with the grazer culture. These experiments demonstrate that grazing by herbivorous protists may be an important sink for DMSP in marine waters, removing a potential source of DMS. Microzooplankton grazing may also indirectly increase the production of DMS by transferring algal DMSP to the dissolved pool, making it available for bacterial metabolism.

  7. PRODUCTIVITY OF A SILVOPASTORAL SYSTEM UNDER INTENSIVE MIXED SPECIES GRAZING BY CATTLE AND SHEEP

    Directory of Open Access Journals (Sweden)

    Leonor Yalid Manriquez-Mendoza

    2011-11-01

    Full Text Available The presence of forage trees in pastures enhances yield and nutritional quality of forage available for animal feeding. We assessed forage yield and nutritional quality, and weight gain of cattle and sheep foraging in a silvopastoral system containing Guazuma ulmifolia Lam. and the grasses Digitaria eriantha Stent (cv. Pangola, Brachiaria brizantha (Hochst. ex A. Rich. Stapf (cv. Insurgentes and Megathyrsus maximus (Jacq. B.K. Simon & S.W.L. Jacobs (cv. Tanzania, during three seasons (windy, dry and rainy in two grazing treatments: 1 mixed species grazing by four to five Criollo Lechero Tropical heifers and six female Pelibuey lambs, and 2 simple species grazing by 12 female Pelibuey lambs. Weight gain was greater (P

  8. Experiment and application of soft x-ray grazing incidence optical scattering phenomena

    Science.gov (United States)

    Chen, Shuyan; Li, Cheng; Zhang, Yang; Su, Liping; Geng, Tao; Li, Kun

    2017-08-01

    For short wavelength imaging systems,surface scattering effects is one of important factors degrading imaging performance. Study of non-intuitive surface scatter effects resulting from practical optical fabrication tolerances is a necessary work for optical performance evaluation of high resolution short wavelength imaging systems. In this paper, Soft X-ray optical scattering distribution is measured by a soft X-ray reflectometer installed by my lab, for different sample mirrors、wavelength and grazing angle. Then aim at space solar telescope, combining these scattered light distributions, and surface scattering numerical model of grazing incidence imaging system, PSF and encircled energy of optical system of space solar telescope are computed. We can conclude that surface scattering severely degrade imaging performance of grazing incidence systems through analysis and computation.

  9. Phosphorus fertilizer and grazing management effects on phosphorus in runoff from dairy pastures.

    Science.gov (United States)

    Dougherty, Warwick J; Nicholls, Paul J; Milham, Paul J; Havilah, Euie J; Lawrie, Roy A

    2008-01-01

    Fertilizer phosphorus (P) and grazing-related factors can influence runoff P concentrations from grazed pastures. To investigate these effects, we monitored the concentrations of P in surface runoff from grazed dairy pasture plots (50 x 25 m) treated with four fertilizer P rates (0, 20, 40, and 80 kg ha(-1) yr(-1)) for 3.5 yr at Camden, New South Wales. Total P concentrations in runoff were high (0.86-11.13 mg L(-1)) even from the control plot (average 1.94 mg L(-1)). Phosphorus fertilizer significantly (P pasture biomass (P dairy pastures should be the maintenance of soil P at or near the agronomic optimum by the use of appropriate rates of P fertilizer.

  10. Land management and development

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... land related data. It is argued that development of such a model is important or even necessary for facilitating a holistic approach to the management of land as the key asset of any nation or jurisdiction.......Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... encompasses the total natural and built environment. Land Administration Systems (LAS) are institutional frameworks complicated by the tasks they must perform, by national cultural, political and judicial settings, and by technology. This paper facilitates an overall understanding of the land management...

  11. Globalization and Land-Use Transitions in Latin America

    Directory of Open Access Journals (Sweden)

    H. Ricardo. Grau

    2008-12-01

    Full Text Available Current socioeconomic drivers of land-use change associated with globalization are producing two contrasting land-use trends in Latin America. Increasing global food demand (particularly in Southeast Asia accelerates deforestation in areas suitable for modern agriculture (e.g., soybean, severely threatening ecosystems, such as Amazonian rain forests, dry forests, and subtropical grasslands. Additionally, in the coming decades, demand for biofuels may become an emerging threat. In contrast, high yields in modern agricultural systems and rural-urban migration coupled with remittances promote the abandonment of marginal agricultural lands, thus favoring ecosystem recovery on mountains, deserts, and areas of poor soils, while improving human well-being. The potential switch from production in traditional extensive grazing areas to intensive modern agriculture provides opportunities to significantly increase food production while sparing land for nature conservation. This combination of emerging threats and opportunities requires changes in the way the conservation of Latin American ecosystems is approached. Land-use efficiency should be analyzed beyond the local-based paradigm that drives most conservation programs, and focus on large geographic scales involving long-distance fluxes of products, information, and people in order to maximize both agricultural production and the conservation of environmental services.

  12. Evaluation of dairy cows intake behavior grazing Brachiaria brizantha fed different levels of concentrate at diet

    Directory of Open Access Journals (Sweden)

    Fabrício Bacelar Lima Mendes

    2013-12-01

    Full Text Available The objective with this research was to evaluate the dairy cows intake behavior grazing Brachiaria brizantha submitted to different levels of concentrate supplementation in the diet. Used 16 lactating cows ½ Holstein x ½ Zebu, with an average of 80 ±10.14 days of lactation and body weight of 454.7 ± 54.51 kg. The animals were distributed in four treatments, using a 4x4 Latin square. The evaluation of behavior was done every ten minutes, during 24 hours on the 16th day of period. We used analysis of variance and regression probability of 0.05. The time spent grazing, ruminating and other activities, the numbers of grazing, ruminating, of bites per day and chews per cake, the grazing times, total power and total chewing, bit rate, time to swallow; time per bolus ruminated; chewing speed and power efficiency for NDF were not altered by increased levels of concentrate. The time of trough, the trough period, the bit size, the chews time for bolus, feeding efficiency for DM, NFC, and TDN and rumination efficiency linearly increased. Periods of rumination, deglutition bits, number of rumination chews per day, decreased linearly with increasing levels of concentrate. Significant quadratic effect of concentrate level on the number of periods in other activities and over time on other activities. Supplementation with 33.8% concentrate in the diet of cows grazing not promote changes in the activity of grazing, ruminating and other activities, but increases the time of trough. The increase in concentrate diet improves the efficiencies of feeding and rumination

  13. Grazing of particle-associated bacteria-an elimination of the non-viable fraction.

    Science.gov (United States)

    Gonsalves, Maria-Judith; Fernandes, Sheryl Oliveira; Priya, Madasamy Lakshmi; LokaBharathi, Ponnapakkam Adikesavan

    Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42h showed that at the end of 24h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, 'k' value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g)=0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, 'g' of non-viable fraction (particle-associated bacteria=0.615, Free=0.0086) was much greater than the viable fraction (particle-associated bacteria=0.056, Free=0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the "persistent variants" where the viable fraction multiply and release their progeny. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  14. Microzooplankton grazing and phytoplankton growth in marine mesocosms with increased CO2 levels

    Directory of Open Access Journals (Sweden)

    Y. Carotenuto

    2008-08-01

    Full Text Available Microzooplankton grazing and algae growth responses to increasing pCO2 levels (350, 700 and 1050 μatm were investigated in nitrate and phosphate fertilized mesocosms during the PeECE III experiment 2005. Grazing and growth rates were estimated by the dilution technique combined with taxon specific HPLC pigment analysis. Microzooplankton composition was determined by light microscopy. Despite a range of up to 3 times the present CO2 levels, there were no clear differences in any measured parameter between the different CO2 treatments. During days 3–9 of the experiment the algae community standing stock, measured as chlorophyll a (Chl-a, showed the highest instantaneous grow rates (k=0.37–0.99 d−1 and increased from ca. 2–3 to 6–12 μg l−1, in all mesocosms. Afterwards the phytoplankton standing stock decreased in all mesocosms until the end of the experiment. The microzooplankton standing stock, that was mainly constituted by dinoflagellates and ciliates, varied between 23 and 130 μg C l−1 (corresponding to 1.9 and 10.8 μmol C l−1, peaking on day 13–15, apparently responding to the phytoplankton development. Instantaneous Chl-a growth rates were generally higher than the grazing rates, indicating only a limited overall effect of microzooplankton grazing on the most dominant phytoplankton. Diatoms and prymnesiophytes were significantly grazed (12–43% of the standing stock d−1 only in the pre-bloom phase when they were in low numbers, and in the post-bloom phase when they were already affected by low nutrients and/or viral lysis. The cyanobacteria populations appeared more affected by microzooplankton grazing which generally removed 20–65% of the standing stock per day.

  15. Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

    Directory of Open Access Journals (Sweden)

    Simonetta Dovier

    2010-09-01

    Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

  16. Grazing of particle-associated bacteria-an elimination of the non-viable fraction

    Directory of Open Access Journals (Sweden)

    Maria-Judith Gonsalves

    Full Text Available Abstract Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ‘k’ value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g = 0.564, the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, ‘g’ of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086 was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068. Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the “persistent variants” where the viable fraction multiply and release their progeny.

  17. Landing spot selection for UAV emergency landing

    NARCIS (Netherlands)

    Eendebak, P.T.; Eekeren, A.W.M. van; Hollander, R.J.M. den

    2013-01-01

    We present a robust method for landing zone selection using obstacle detection to be used for UAV emergency landings. The method is simple enough to allow real-time implementation on a UAV system. The method is able to detect objects in the presence of camera movement and motion parallax. Using the

  18. In situ provision of drinking water to grazing dairy cows improves milk production.

    Science.gov (United States)

    Miglierina, M M; Bonadeo, N; Ornstein, A M; Becú-Villalobos, D; Lacau-Mengido, I M

    2018-01-01

    To determine the effect of providing water within the area grazed by dairy cows on milk yield and quality, compared to requiring cows to walk to a distant water trough, on a dairy farm in the Pampa region of Argentina during summer. Holstein dairy cows were allocated to two herds with similar parity, days in milk and milk production. They were grazed in one paddock that was divided in two, with a fixed water trough at one end. Cows were moved twice daily to grazing plots within the paddock. Control cows (n=66) could only access water from the fixed trough, whereas supplemented cows (n=67) also received water from a mobile trough within the grazing plot. Milk production of each cow, and water consumption of the two herds were measured daily over 62 days. Milk composition for each herd was determined weekly from Days 18 to 60 of the study, and grazing behaviour was observed between 08:00 and 16:00 hours on Days 11-15, 19-22 and 39-43. Over the 62 days of the study, supplemented cows produced 1.39 (SE 0.11) L/cow/day more milk than Control cows (p=0.027). Estimated mean daily water intake was 50.4 (SE 2.1) L/cow/day for supplemented cows and 58.2 (SE 2.7) L/cow/day for Control cows (p=0.004). Percentage total solids in milk was higher for supplemented (12.5 (SE 0.06)%) than Control (12.4 (SE 0.04)%) cows (p=0.047). During the periods of behavioural observation, a higher percentage of cows in the water supplemented than the Control herd were observed in the grazing area (p=0.012). This preliminary study demonstrated that provision of water to dairy cows within the grazing plot was beneficial for milk production and composition, and may be associated with longer periods spent within the grazing area, during hot weather in the Pampa region of Argentina.

  19. Selective grazing from protist over enteric bacteria in an aquatic system

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, M. S.; Escalante, A. H.; Folabella, A. M.; Zamora, A. S.

    2009-07-01

    Its very clear that the grazing from protozoan can be an important source of mortality for the suspended bacteria, both in marine and freshwater environments. Considering that the presence of fecal contamination its a frequent phenomenon in this environments, and that Escherichia coli and members of Enterococcus genera are indicators of microbiology water quality, we analyze the effect of grazing from protozoan over E. coli and Enterococcus faecalis in de Los Padres Lagoon waters (Buenos Aires, Argentina) 37 degree centigrade 56'30'' S, 57 degree centigrade 44'30'' W). (Author)

  20. The impact of sheep grazing on the carbon balance of a peatland

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, Fred, E-mail: Fred.Worrall@durham.ac.uk; Clay, Gareth D.

    2012-11-01

    Estimates of the greenhouse gas (GHG) fluxes resulting from sheep grazing upon upland peat soils have never been fully quantified. Previous studies have been limited to individual flux pathways or to comparing the presence to the absence of sheep grazing. Therefore, this study combines a model of the physical impact of grazing with models of: biomass production; energy usage in sheep; and peat accumulation. These combined modelling approaches enabled this study to consider the indirect and direct impacts of sheep upon the carbon and greenhouse gas balance of a peatland at different grazing intensities as well as the changes between grazing intensities. The study considered four vegetation scenarios (Calluna sp., Molinia sp.; reseeded grasses, and Agrostis-Festuca grassland) and a mixed vegetation scenario based upon the vegetation typical of upland peat ecosystems in northern England. Each scenario was considered for altitudes between 350 and 900 m above sea level and for grazing intensities between 0.1 and 2 ewes/ha. The study can show that the total GHG flux at the vegetative carrying capacity tended to decline with increasing altitude for all vegetation scenarios considered except for Molinia sp. The average total GHG flux for all scenarios was 1505 kg CO{sub 2}eq/ha/yr/(ewe/ha), and on average 89% of the fluxes were directly from the sheep and not from the soil, and are therefore not unique to a peat soil environment. The study suggests that emission factors for upland sheep have been greatly underestimated. By comparing the total flux due to grazers to the flux to or from the soil that allows the study to define a GHG carry capacity, i.e. the grazing intensity at which the flux due to grazing is equal to the sink represented by the peat soils, this GHG carrying capacity varies between 0.2 and 1.7 ewes/ha with this capacity declining with increasing altitude for all model scenarios. -- Highlights: Black-Right-Pointing-Pointer Vegetative carrying capacity was