Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2025
Abstract
No abstract has been registered
Authors
Jian Liu Faruk Djodjic Barbro Ulén Helena Aronsson Marianne Bechmann Lars Bergström Tore Krogstad Katarina KyllmarAbstract
No abstract has been registered
2024
Authors
Sigrid Esmeralda ArnestadAbstract
På norske gravplasser er plassmangel et problem grunnet svært treg nedbrytning av menneskekropper som fremdeles kan være intakte etter flere tiår i en kistegrav. Ved etablering av nye gravfelt har masseutskifting med blandinger av maskinelt knust sand blitt benyttet for å sikre god drenering. Det eksisterer derimot lite kunnskap om langtidseffekten av denne type kunstig jord på nedbrytning i kistegraver. Knust sand fra stein har troligere høy pH og skarpere overflater som sannsynligvis pakkes annerledes enn naturlig rundet sand, hvilket kan ha betydning for jordfysiske egenskaper og påvirke transport og innhold av vann og luft. De antatte egenskapene kan påvirke forhold som styrer den mikrobielle aktiviteten, som er avgjørende for god nedbrytning. Oppgaven har derfor som formål å bidra til økt kunnskap om egenskaper til knust sand gjennom å karakterisere fysiske, hydrauliske og kjemiske egenskaper, samt å undersøke jordmassenes påvirkning på organisk mikrobiell nedbrytning. Ulike tester ble gjennomført i et lysimeteranlegg på følgende utvalg av sand; to typer knust sand, to naturlige sand, og fire typer blandinger av disse. Teposer ble begravd i to dybder med kontrollert vannstand og standard fysiske og kjemiske analyser samt vannlagringskapasitet ble undersøkt på jordprøver i lab. I tillegg ble infiltrasjonshastighet målt på jordmassene i lysimetrene. Resultatene fra studiet viste at massetap av te var signifikant mindre i knust enn naturlig sand, forholdsvis i det øvre jordlaget. Det antas at dette i hovedsak skyldes redusert mikrobiell nedbrytning, trolig som følge av høyere pH, lavt innhold av organisk materiale og for lite fuktighet i de knuste massene. Sistnevnte antakelig på grunn av lav vannlagringskapasitet. Nedbrytning av te var generelt lavere i det nedre jordlaget, trolig grunnet redusert oksygen som følge av mer fuktighet fra den nærliggende vannstanden. I de groveste kunstige og naturlige sandtypene ble det derimot ikke observert redusert nedbrytning i det nedre jordlaget, mulig som følge av fravær av kapillært vann fra den nærliggende vannstanden og antakelig fremdeles opprettholdelse av aerob mikrobiell aktivitet. Samtidig bør det bemerkes at forskjellene i nedbrytning stort sett ikke var signifikante mellom noen av jordtypene i dette jordlaget. Sandpartiklene ser ut til å være betraktelig mer kantet enn de naturlige, men studien viste ingen overbevisende forskjell i total porøsitet og det er behov for mer forskning på langtidseffekten av konsolidering som følge av forskjeller i partikkelform. I alt indikerer resultatene at mikrobiell nedbrytning kan begrenses i knust sand sammenliknet med naturlig, noe som vil være ugunstig dersom massene benyttes på kirkegårder der det er ønske om høy mikrobiell aktivitet og nedbrytning.
Authors
Hanna Marie KjernsbyAbstract
Finansiert av Statens Vegvesen
Authors
Elias GarvikAbstract
The Norse built their hulls from oak boards hewn from cleaved or ‘rived’ logs. We know this through artworks and texts as well as archaeological finds describing the ships as well as their construction from the latter half of the early-medieval period. However, we know summarily little when it comes to the pre-production of hewn boards. I ask, - How could the Norse have possibly cleaved? - Which properties in white oak affect cleaving? - Which simple truths can be found of cleaving. Which direction of cleaving is best for oak? This is done by showcasing the differences in cleaving from the top, side, and bottom of a series of white oak logs. Namely why cleaving from each direction fails. To summarize the results. Cleaving from the top shines in cases where there is a large difference in the diameter at the top and bottom of the log. Cleaving from the side can act as a mitigator in the case of knots or to pierce directly through a knot or burl. Cleaving from the top or bottom falls more naturally in the cases where the pith is off-centre. With a log bent like an arch, cleaving from the side fell more naturally. The direction of the cleave ought to be thought of less as an immutable truth and more of as another tool to extract as many boards from a log as possible. We found that no direction of cleaving was inherently better in all scenarios. It is a case of risk-mitigation, which benefits from taking a thorough look at the log and making an informed choice. In cases where the angle of the twisting fibres of a log is significant, all cleaving directions struggle and fail, in cases where there are few natural faults, cleaving from all sides succeed.
Authors
Einar Lyche LebesbyeAbstract
Land-based wind power is considered one of the most applicable sources of renewable energy for the future. While cost effective, the knowledge of ecological consequences associated with construction and operation is limited. This thesis investigates how vegetation and cervid animals at Lista Wind Park were affected by its construction and operation. Vegetation data in revegetated and control plots were compared over a twelve-year period and tested for variation in species richness, species diversity and foliar coverage. Dispersal of alien species, as a result of infrastructure construction, was also investigated. Cervid habitat use was mapped one year before, during construction and several different years after the wind park was set into operation. This data was considered unreliable due to inconsistency in sampling circumstances and lack of calibration between observers, and not analysed further. Rather, inter-observer discrepancies in species identification were investigated. Vegetation in revegetated plots seems to converge towards control plots after twelve years. Differences in species richness, species diversity and foliar cover are no longer significant. However, models fail to account possible variations due to climate. The construction of the wind park resulted in dispersal of alien species. In general, experienced observers had trouble identifying species though photographs of feces, only being certain in ca. 50% of the cases. In cases where observers were certain, species ID was different compared to another observer in 19% of the cases. More studies are needed to determine land-based wind powers ecological consequences, especially on cervids.
Authors
Elise Lyng MonssenAbstract
Wildlife-train collisions are a widespread issue, leading to significant costs to society, reduced animal welfare and potential impacts on species' population sizes. Understanding how ungulates respond to oncoming trains and what affects their detectability is crucial for developing effective mitigation strategies. Building upon the work of Bhardwaj et al. (2022), this study investigates how various factors influence flight behaviour in fallow deer (Dama dama), roe deer (Capreolus capreolus) and moose (Alces alces), as well as wildlife detection from the train driver's perspective. By utilizing films from driver-activated scare systems (DASS) mounted on the front windshield of trains on Norwegian and Swedish railways, this study offers insights into both wildlife reactions and the viewpoints of train drivers. Based on approximately 1000 observations of ungulates, each individual encounter with trains was analysed in relation to railway features, train speed, the train driver’s use of typhoon warning, the ungulates’ location within the terrain and biotic and abiotic factors in the surrounding landscape of the railway. Detection distance and flight initiation distance (FID) was calculated based on the video footage. The results showed that with increasing distance from the railway tracks, ungulates in total were less likely to flee from an approaching train and more likely to increase their FID. Generally, there was a higher probability of flight when the typhoon was used to warn the ungulates, but the effect of this signal was not significant in any of the separate analyses on each species alone. There was also a higher likelihood of flight during dusk/dawn. Flight behaviour of fallow deer was significantly influenced by herd size, with a greater likelihood of flight in smaller groups separated from a large herd. In contrast to roe deer and fallow deer, moose were significantly affected by train speed, with flight likelihood and FID decreasing with increasing speed. All species showed a significantly higher probability of flight across track with closer distance to the track, and in areas where the rail embankment was covered by vegetation with exception of roe deer. Additionally, ungulates in total had a higher probability of an early flight, before detected by the train driver, when visibility was obstructed by vegetation, terrain and curvature of the railway. Lastly, detection distance from the train driver’s perspective was significantly obstructed by vegetation along the railroad embankment. Further studies are suggested on a warning system that could be activated before the animals are detected by the train driver to increase animals’ FID, alongside the implementation of night vision cameras for improved detection of animals during nocturnal hours.
Authors
Hanna Ellisiv KringstadAbstract
Potato haulm killing is a prevalent practice in the global potato production to ease vine management, aid tuber maturation and remove late blight inoculum. EU’s ban of the herbicide diquat (e.g. in the product Reglone) to kill potato haulm, has left the producers and scientists in need to find alternative measures. Five different doses of hot water were tested in combination with mechanical haulm flailing, to study their ability to kill potato haulm in an open field in Innlandet, Norway. Remaining fresh stem and leaves, and number of plants with regrowth, were observed visually 7 times over 21 days following the hot water treatment. There were found significant differences in fresh leaves and stem over time when comparing mechanically flailed plants to the naturally senesced counterparts, but no added effect in senescence was found by adding any of the doses of hot water. Quality analysis of the harvested tubers considering yield, size distribution, green tubers, abrasion injury and disease, found no effect of the different treatments on any of the quality parameters.
Authors
Emma SkogstadAbstract
In cereal production plant pathogens cause yield losses, and management strategies for controlling them are important. Cover crops as a part of the cereal production have beneficial properties for the soil health, can increase the biological diversity in the fields, and the soil structure can be improved, additionally cover crops can reduce soil erosion. Therefore, this thesis argues that implementing cruciferous plants as part of the cover crops have the potential to reduce plant pathogens. Cruciferous plants used as cover crops have shown to reduce plant pathogens survival both in laboratory and field plots. The suppression is due to the volatile glucosinolate (GLS) and isothiocyanate (ITC) content cruciferous plants. As a part of a project at NIBIO Ås, an in vitro experiment with allyl ITC were done to look at the effect on survival of Heterodera avenae, Fusarium graminearum and Microdochium nivale, with increasing allyl ITC concentration. Also, a closed jar experiment was conducted to look at the effects of cruciferous plants on suppression of survival of Heterodera avenae and Fusarium graminearum. The aim of the in vitro experiment was to see at which concentrations of allyl ITC that suppressed fungal growth of F. graminearum and M. nivale and hatching of the cereal cyst nematode H. avenae. The EC50-values of the F. graminearum isolates 200 630, 201 196 and 202 058, were 6.36, 9.50 and 7.62 mg/L respectively. EC50-values of M. nivale isolates 200 136, 200 231 and 202 786, were 8.60, 10.83 and 10.27 mg/L respectively. For H. avenae, the EC50-value was at 5.66 mg/L. This demonstrates a differentiation of EC50-values between nematodes and fungi, but also between fungal species and fungal isolates. A closed jar experiment was conducted to see if incorporation of cruciferous plants in soil may affect the survival of H. avenae and F. graminearum. Two different time exposures in jars with either two or eight weeks of exposure in jars, were performed. After treatments in jars, the cysts were given either a diapause or no diapause treatment. The total number of eggs and J2 were significantly lower for cysts exposed for eight weeks in jars compared to two weeks, but the total number of eggs and J2 were almost equal for diapause and no diapause. The number of hatched J2 (15°C) for cysts with diapause treatment had significantly higher number of J2 than no diapause treatment. Also, the number of hatched J2 were significantly higher for two weeks exposure in jars compared to eight weeks. The mycelial growth from F. graminearum on oat spikelet incorporated in soil with plant material was not different from untreated.
Authors
Maria KorkouAbstract
PhD thesis in City and regional planning