169 research outputs found
Background data for: Soil characteristics at artificial salt licks and their potential impacts on occurrence of chronic wasting disease
No full textBackground Data for Soil characteristics at artificial salt licks and their potential impacts on occurrence of chronic wasting diseaseAbstract
Salt lick sites, where artificial salt blocks are placed at permanent locations, are common in summer grazing areas for free ranging sheep in Norwegian mountains. These areas often overlap with areas used by wild reindeer and reindeer are frequently observed at these salt lick sites. The first cases of chronic wasting disease (CWD) were discovered among Norwegian wild reindeer in 2016, and salt lick sites were presumed to be hotspots for transmission of CWD. In this study we compare soil properties at salt lick and nearby control sites not affected by salt blocks, and review how salt-induced changes may influence persistence and transmission of CWD. Three wild reindeer areas were studied: one CWD-affected area, Nordfjella, and two areas without CWD, Knutshø and Forollhogna. The soils at the salt lick sites were strongly influenced by dissolving salt blocks and increased animal activity. The salt lick sites had higher pH and ionic strength and increased levels of sodium (Na), chlorine (Cl), calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn) and iodine (I), reflecting the composition of the salt blocks. The increased animal activity was reflected in eroded topsoil causing less soil organic matter (SOM), and there were higher amounts of elements related to defecation and urination, giving higher concentrations of inorganic nitrogen (Inorg-N), phosphate (PO4-P), sulphate (SO4-S), potassium (K) as well as high gastrointestinal parasite frequency and diversity. The high salt content in the salt lick soils may stimulate geophagy and as the soil is heavily contaminated by animal excretions, this may facilitate prion transmission. In addition, the high pH and ionic strength in the salt licks soils increases both the cation attraction and anion diffusion towards the soil particles thereby facilitating both persistence and transmission of CWD. There was an increase in salinity at the salt lick sites in a gradient from west to east most likely related to the coinciding decrease in precipitation. This suggest that if the use of permanent salt lick sites is discontinued the salt lick sites in the east will maintain their attraction for congregating animals and geophagy longer than the western sites
Magnetic activity and hot Jupiters of young Suns : the weak-line T Tauri stars V819 Tau and V830 Tau
Get PDFSGG acknowledges support from the Science & Technology Facilities Council (STFC) via an Ernest Rutherford Fellowship [ST/J003255/1]. SHPA acknowledges financial support from CNPq, CAPES and Fapemig. AAV acknowledges support from the Swiss National Science Foundation (SNSF) via the allocation of an Ambizione Followship. Date of Acceptance: 06/08/2015We report results of a spectropolarimetric and photometric monitoring of the weak-line T Tauri stars (wTTSs) V819 Tau and V830 Tau within the MaTYSSE (Magnetic Topologies of Young Stars and the Survival of close-ingiant Exoplanets) programme, involving the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope. At ≃3 Myr, both stars dissipated their discs recently and are interesting objects for probing star and planet formation. Profile distortions and Zeeman signatures are detected in the unpolarized and circularly polarized lines, whose rotational modulation we modelled using tomographic imaging, yielding brightness and magnetic maps for both stars. We find that the large-scale magnetic fields of V819 Tau and V830 Tau are mostly poloidal and can be approximated at large radii by 350-400 G dipoles tilted at≃30° to the rotation axis. They are significantly weaker than the field of GQ Lup, an accreting classical T Tauri star (cTTS) with similar mass and age which can be used to compare the magnetic properties of wTTSs and cTTSs. The reconstructed brightness maps of both stars include cool spots and warm plages. Surface differential rotation is small, typically ≃4.4 times smaller than on the Sun, in agreement with previous results on wTTSs. Using our Doppler images to model the activity jitter and filter it out from the radial velocity(RV) curves, we obtain RV residuals with dispersions of 0.033 and 0.104km s-1 for V819 Tau and V830 Tau, respectively. RV residuals suggest that a hot Jupiter may be orbiting V830 Tau, though additional data are needed to confirm this preliminary result. We find no evidence for close-in giant planet around V819 Tau.Peer reviewe
Soil carbon and glacifluvial deposits in the deglaciation landscape of Gausdal Vestfjell
Get PDFGlacifluvial deposits and their soil carbon stock and stability have been studied in the deglaciation landscape of Gausdal Vestfjell, Norway. Soil profiles are described and sampled for parent material clast analysis, density calculation and soil chemical analysis across a variety of glacifluvial landforms deposited in both flowing and stagnant ice, subaerially as well as subaqueously. The landforms include eskers, kame, kame terraces, delta and fan deposits. The morphology and sedimentology of 17 landforms are described and interpreted from remote sensing and field investigation. Methods have included visualization of LiDAR data in ArcMap, stratigraphic logging, sediment property analysis and Ground Penetrating Radar measurements. Calculation of carbon stock is based on soil density, stone and boulder content, horizon thickness and laboratory measurements of total carbon content.
Gausdal Vestfjell was deglaciated by down-wasting of stagnant ice, where kame terraces at the highest elevations (820-890 masl) record a progressive lowering of the ice surface. Fan, delta and sandur deposits record ice-damming and gradual drainage of meltwater from the lowest elevations (778-810 masl). The glacifluvial deposits are subangular, sorted and mainly composed of sand and gravel although both finer and coarser sediments occur. The deposits are dominated by tabular and through cross bedding, current ripples and horizontal lamination, erosive surfaces and variable discharge mainly in the upper flow regime.
The carbon stocks can be linked to depositional environments and processes during deglaciation. Early and late stage deposition at high (~890 masl) and low elevation (~790 masl), respectively, resulted in low carbon stocks, while deposition in stagnating ice at intermediate elevations is linked to high carbon stocks (~850 masl). The coarse texture of the deposits limits carbon input, decomposition, translocation and stabilisation due to low total particle surface area and water and nutrient retention capacity. Soil texture further exerts a major influence on carbon stocks through organic material occlusion and complexation with minerals, and a doubling of the silt and clay content from 20 % to 40 % nearly triples carbon stock. The texture varies greatly due to large variations between and within depositional environments and processes, and the glacifluvial carbon stocks are thus linked to the formation of the landforms they are found on.
The carbon stock of the soils is estimated down through the Bs horizon, and ranges from ~ 3 to 18 kg/m2, with a mean estimated to 7.99 kg/m2. The fraction stored in the mineral soil is highly variable and ranges from ~10 % to ~ 100 %, averaging at 63 %. Soil organic carbon varies with the nutrition status of the nearby bedrock and parent material, the degree of soil formation and the nature of sediment transport and deposition. The degree of soil formation is higher in soils formed from innutritious parent material. The soil carbon stock is higher in soil formed on landforms composed of immature sediment, deposited in the lower flow regime and with a low relief with the surrounding landscape. Stabilisation of organic carbon in the mineral soil depends on the presence of clay minerals in the parent material and soil weathering products including iron and aluminium oxides and phyllosilicates. Mineral-stabilised carbon in soil of nutritious parent material may show higher chemical recalcitrance, while carbon stabilised in more acidic soils formed from less nutritious parent material may be more labile and to a larger degree stabilised by oxides.
Upscaling of carbon stock estimates from the detailed study of selected landforms was done by georeferencing a bedrock map and a topographic map based on LiDAR data to all landforms mapped by remote sensing in the study area (c. 500). Parent material nutrition status can be inferred from the local bedrock, and the nature of deposition from the shape of landforms and their relationship with the surrounding landscape. The small number of deposits studied provides no statistical significance for extrapolation, however, the trends and variation in the carbon stocks of glacifluvial soils appear to be predictable. By upscaling, the organic horizon carbon stocks of the glacifluvial soils were estimated to be equivalent to ~121 Mg CO2/ha, and the carbon stocks of the mineral soil horizons to ~ 241 Mg CO2/ha. The former is unstable and may be lost from the deglaciation landscape to the atmosphere in a warmer climate while the latter may be lost if there is a change in land use. Overall, the landforms show large carbon stock variations for both organic and mineral soil horizons. Calculated values are comparable to values obtained in previous studies for carbon stocks of forest soils in mountainous ecosystems.Glasifluviale avsetninger og deres karbonlager er studert i isavsmeltingslandskapet i Gausdal Vestfjell, Oppland. Jordprofiler fra fire glasifluviale landformer er beskrevet, og det er tatt prøver for analyse av opphavsmateriale, jordtetthet og jordkjemiske egenskaper fra tolv landformer. Morfologien og sedimentologien til i alt 17 landformer, inkludert eskere, kame, kameterrasse, delta og vifteavsetninger er beskrevet og tolket basert på fjernanalyse og feltundersøkelse, blant annet ved fremstilling av LiDAR-data i Arc MAP, stratigrafisk logging, analyse av sedimentegenskaper og geroradarmålinger. Beregning av karbonlager er basert på jordtetthet, innhold av stein og blokk, sjikttykkelse, og laboratorieanalyse av jordas innhold av total karbon.submittedVersionM-MIN
Karbonlagring i Heståsmyra nordvest
Get PDFSom følge av de globale klimaendringene er det en økende interesse for myra som karbonlager. For å bidra til ytterligere informasjon om temaet er karboninnholdet i den nordvestre delen av Heståsmyra på Sjusjøen i Innlandet fylke undersøkt i denne oppgaven. Dette er gjort ved hjelp av georadar, myrkjerner og naturtypekartlegging etter Natur i Norge- systemet.
Heståsmyra nordvest er kartlagt som jordvannsmyr og dekker et areal på 36 227,2 m2. Volumet av myra ble funnet ved fire georadarmålinger, og er estimert til 50 174,75 m3. På grunn av liten penetrasjonsdybde er bare volumet for de øverste 2 meterne kartlagt. Det er tatt ut seks myrkjerner som er plassert i georadartransektene. Fire av disse har en dybde på 50 cm, mens to av de har dybde på 75 og 150 cm.
Analyser av myrkjernene viser et gjennomsnittlig karboninnhold på 51,72 % og en gjennomsnittstetthet på 0,13 g/cm3. Både tettheten og karboninnholdet øker med dybden. Som ventet ut fra resultatet av andre studier, er det funnet en sterk lineær sammenheng mellom karboninnhold og tetthet. Det er gjort fargemålinger med både Munsell fargekart og en digital fargemåler, Nix Pro 2. Basert på resultatene fra fargemålingene og korrelasjonsanalysene som er utført, ser det ut til at Nix Pro 2 gir like god informasjon som den tradisjonelle metoden. For begge metodene er det funnet en signifikant negativ korrelasjon mellom lysheten på jorda og karboninnholdet.
Karbonlageret i Heståsmyra er estimert til 40,35 kg/m2. Karbonberegningene gjelder for de øverste 1,5 meterne. Det er stor usikkerhet knyttet til beregningene. Den største usikkerheten er knyttet til de dypeste lagene som følge av et svært lite prøveutvalg. Det totale karboninnholdet i Heståsmyra nordvest er estimert til 3358,28 ± 554,83 tonn. Det tilsvarer 12,32 Gg CO2-ekvivalenter.As a result of global climate change, there is a growing interest in the peatlands as a carbon store. In order to contribute to further information on the topic, the carbon content in the north-western part of Heståsmyra on Sjusjøen in Innlandet county has been examined in this master thesis. This has been done with the help of ground-penetrating radar (GPR), peat cores and a mapping of nature types according to the “Natur i Norge”-system.
Heståsmyra northwest is classified as a minerogenic peat and covers an area of 36 227.2 m2. The peat volume was found by the four transects in the GPR-survey and is estimated to 50 174.75 m3. Due to small penetration depth, the volume has been estimated for the top 2 meters only. The peat cores were sampled in the GPR-transects. Four of the cores have a depth of 50 cm, while the two others have a depth of 75 cm and 150 cm.
Analysis of the peat cores shows an average carbon content of 51.72 % and an average density of 0.13 g/cm3. Both the density and the carbon content increase with depth. As expected from the results of other studies, a strong linear relationship between carbon content and density has been found. The color of the peat samples has been measured with both Munsell color charts and a digital color sensor, Nix Pro 2. Based on results from the color measurements and correlation analysis that have been carried out, it appears that Nix Pro 2 provides just as good information as the traditional method. For both methods, a significant negative correlation has been found between the lightness of the soil and the carbon content.
The carbon stock in Heståsmyra is estimated at 40.35 kg/m2. The carbon stock is estimated for the top 1.5 metres. There is great uncertainty connected to the calculations, including a small sample size for the deepest layers. The total carbon content in Heståsmyra northwest is estimated to 3358.28 ± 554.83 tons. This corresponds to 12.32 Gg CO2 equivalents
Effect of grazing in Norwegian outfields related to the quantity and quality of soil organic carbon and other soil properties
Get PDFUtilization of the outfield for grazing have long traditions in Norway. Not only as a pasture, but also mowed to provide food for the winter (Rekdal & Angeloff, 2021). From 1949 to 1999, grazing in Norway changed from being dominated by livestock to being equally grazed between wild herbivore and livestock (Austrheim et al., 2011). This change in usage has led several of the semi-natural habitat types to end up on the red list of the Norwegian Biodiversity Information Centre, such as Semi-natural meadow and Hayfields (Hovstad, 2018). Therefore, grazing in outfield areas in Norway are desired as a way of keeping the cultural landscape. Resent years events particularly, in addition to a growing concern about the world’s food situation has increased the interest for local food production. The latest analysis of grazing and the outfield suitable of such, indicates that Norway’s unused potential in outfield is about 55% (Rekdal & Angeloff, 2021).
In addition to recent years events, the world is facing changes in climate. Still debated on how extensive and where the greatest changes will appear, a change in food production are required to undergo adjustments. Knowledge of management and “best practice” models are therefore crucial. Also in Norway, information on how the soil in outfields are affected by grazing is as important than ever.
In this thesis five locations who differs in climate and vegetation are sampled. All these locations are grazed during the summer season by suckler cows which is a part of the Norwegian meat production. Throughout this thesis grazing was not found to significantly affect the SOC-stock, SOC concentration or the thickness of the organic layer. While grazing was found to significantly decrease the HWEC-stock in all mineral layers and the CN-ratio in the organic layer.
The decrease in the HWEC-stock is suggested caused by removal of organic matter by grazers. The basis for this assumption is partly the combination of the significant decline in HWECstocks and difference between grazed and non-grazed site in the thickness of the organic layer mean values (not significant). In addition, the CN ratio was found to significantly decrease under grazing in the organic layer.
The HWEC-stock is viewed as a measure of the labile fraction (Dong et al., 2021), and is a useful indicator of the soil quality in soil-plant ecosystems (Ghani et al., 2003). The form and behaviour of the SOM and SOC is fully reliant on microbial mass (Bhattacharyya et al., 2022), and a decrease of the HWEC might therefor be a sign that a decline of microbial biomass pool (Ghani et al., 2003) are taking place. Since a significant decrease were found between the grazed site and the control sites (non-grazed) it might be an early indicator of degradation of the soil structure.
A significant increase in bulk density between sites in the two top layers (the organic layer, mineral 0-10 cm) were found for all locations. In accordance with other studies on grazing effects (Byrnes et al., 2018; Martinsen et al., 2012; Piñeiro et al., 2010), it was concluded that the pastures were influenced by the grazing animals.
On the background of different utilizing periods and grazer densities, the management of the pastures is suggested to might be influencing the HWEC-stock. Amongst the tested factors related to geography and effect on the SOC-stock, only MAT were found significant.
Precipitation and content of fine texture quantity were not found to significantly effect SOCstocks. Therefore, geography was found somewhat related to the SOC-stock.
Only Mg-stock had a significant difference between sites. Grazing was not found to significantly affect the soil’s pH. No plausible explanation for this significant result was found. The other macronutrient stocks were not found to significantly change with grazing
Norwegian Journal of Agricultural Sciences : comparison of different systems for classification of seven podzolized, sandy soils in southern Norway
No full textThe 1975 and 1992 versions of Soil Taxonomy, the 1988 version of the FAO-Unesco system, and the 1987 version of the Canadian System of Soil Classification were used to classify seven sandy soils with different degrees of podzolization. None of the soils were classified as Spodosols according to the I975 version of Soil Taxonomy, three were classified Spodosols according to the Keys to Soil Taxonomy 1992, five as Podzols according to the FAO-Unesco system and two were classified as Podzolic according to the Canadian system. The exclusion of soils from the Podzol (Spodosol) orders was due to depth or thickness requirements for the podzolic (spodic) horizon. Indexes based on properties of the mineral soil were used to evaluate the degree of podzolization. Cluster analyses of these indexes were used to group the soils. Comparisons between these groups and the different classifications suggested that the difference in soil
development were reflected best by the 1992 version of Soil Taxonomy. A cluster analysis based on the upper podzol B subhorizon properties suggested that the difference in podzol development were best reflected by the Canadian classification
Carbon stock and geological development of a peatland in Karlshaugen nature reserve
Get PDFCarbon stocks of peatlands is of growing interest due to the ability to store large amounts of carbon. To provide data of this subject this master thesis presents results from a study of a peatland within a forest nature reserve outside of Oslo, Norway. First, peat volume was estimated using a combination of ground penetrating radar survey and GIS tools (EkkoPulse software, ArcMap and Excel). Second, sediment cores retrieved from the peat were analysed in the laboratory to analyse the bulk density and carbon content of the organic material and to calculate the carbon stock of the peatland. The data were also used to explain how this peatland has developed.
The volume of the total peatland analysed by the ground penetrating radar was calculated to be 6487 m3. Degree of decomposition, described by the von Post scale, shows similar trends for all four cores; it is low in the shallow peat and increases with depth where they stabilize at level 6-8. Using Loss On Ignition as total amount of organic material gave values well above 90%, except for the samples that visibly contain minerogenic material. These results were consistent with results from total carbon analysis using LECO Truspec instrument finding total carbon content of peat core MM1to be 47-55%. The total carbon content of the remaining three cores were determined by regression analysis to be 50-53% in core MM2, 5154% in core MM3 and 52-54% in core MM4. Carbon stocks in MM1 range from 2 kgC/m2 to 7 kgC/m2. The total amount of carbon stored in this peatland is calculated to be 278 ton. For the top meter the carbon stock is 41.1 kg/m2.
The hypothesis for the formation of this peatland being a depression in bedrock filled with water to form a pond, later filled with sediments and organic material was supported by the shape of the peat basin illustrated in the GPR survey, and the fine minerogenic material in the bottom part of peat core MM1. Further field observations support peatland boundary is changing, and it can be predicted that the rise in temperature and changes in precipitation might cause degradation of organic material in the peatland. This process may be part of a positive feedback loop with climate change
Virkning av conservation farming og biokull på karbon- og nitrogendynamikk i sandig jord i subtropiske klimasoner
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[[alternative]]A Study of Assessing the On-line Learning
No full text[[abstract]]The purpose of this study was to investigate the important issues of assessing the learning performance for corporate on-line learning. It included the status, components, factors affecting the design and meta-evaluation of assessing learning performance for corporate on-line learning. A qualitative method of case study with in-depth interviews was employed to collect the data. Six professionals of on-line learning in various companies were interviewed. The author then converted the recorded tapes into Word files. The main concepts of the files were extracted following a preset data analysis procedure. The findings and conclusions were made based on the analyzed data.
The conclusions are as the followings:
1.The status of using on-line learning systems is still in
its infancy stage.
2.The components of an on-line learning system consist of
a platform and on-line courses.
3.The operational team in charge of the maintenance and
operation of the system. Meanwhile, the learners,
instructors and HR staff are the major participants of
an on-line learning system.
4.The learners usually are able to access the on-line
learning system at anytime but only in the specific
places designated by the company for the reasons of
system security.
5.An on-line learning system can serve as a knowledge
management system for the corporate knowledge
management.
6.The way a leaner using an on-line learning system is one
of the main sources of barriers in promoting on-line
learning.
7.The purposes of learning evaluation are three-fold:
helping the learner to learn, auditing the training
event and improving the training program.
8.The approaches of assessing on-line learning
performances comprise of on-line questionnaire, on-line
test, homework, discussing area, comments area, article
sharing, learning process record, and on-line synchronic
meeting.
9.The timing of evaluation maybe during or after the on-
line learning session.
10.The three basic principles in conducting evaluation are
based on the philosophy of the instructor, the
supporting functions provided by the system platform
and applying evaluation methods elastically.
11.The dimensions of evaluation feedback are audience,
channel and applications of evaluation results.
12.The difficulties of employing on-line evaluation come
from lack of budget, busy learners and the tendency of
answering questions of learners.
13.The factors that affect the choice of evaluation
methods are type of course, instructional strategies,
how easy to use the evaluation tool, background of the
learner and decisions made by evaluation designer or
evaluator.
14.The cost will affect the timing of evaluation.
15.The companies tend not to be concerning about the
fairness and cheating of on-line evaluation.
16.The design of on-line and off-line evaluations is
different.
17.Meta-evaluation of an on-line evaluation is usually
done by HR staff or the instructor.
18.The timing of a meta-evaluation maybe during or after
the on-line learning evaluation.
19.The focuses of meta-evaluation are confirming the
quality of results of the on-line learning evaluation,
adding pre-tests, expanding question bank and verifying
its validity, simplifying the evaluation process and
changing the perspectives of the company toward the on-
line learning evaluation.
Carbon and nitrogen stocks in Norwegian forest soils - the importance of soil formation, climate, and vegetation type for organic matter accumulation
Get PDFRelationships between soil C and N stocks and soil formation, climate and vegetation were investigated in a gridded database connected to the national forest inventory in Norway. For mineral soil orders C and N stocks were estimated to 11.1-19.3 kg Cm-2 and 0.4-0.8kg Nm-2 declining in following order Gleysolic>Podzolic>Brunisolic>Regosolic. Organic-peat type soils stored on average 31.3 kg Cm-2 and 1.1 kg Nm-2, while shallow Organic Folisols, on average store 10.3 kg Cm-2 and 0.3 kg Nm-2. For Norway’s 120 000 km-2 of forest the total soil C stocks was estimated to 1.83 GtC with CL95% 1.71–1.95 GtC. Podzolic soils comprise the largest soil group and they store approximately 50% of the forest soil C. Sixty percent of the soil C stock in Podzolic soils was store in the mineral soil, and increase with temperature and precipitation. Poorly drained soil types store approximately 47 % of the total forest soil C in Norway. Poorly drained soil have large C stocks mainly in the surface layers suggesting that they are more susceptible to forest management and environmental change.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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