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.
2024
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
Authors
Islam, Md ShaidAbstract
Begonias, known for their ornamental value in shade gardens, are highly susceptible to viral infections, which not only deform the plants themselves but also pose a risk of spreading to adjacent cropping plants. This susceptibility underscores the importance of understanding the viral pathogens affecting begonias, especially considering their role as hosts for aphids that can transmit these viruses to economically significant crops. In this study, an initial examination was conducted on 10 begonia specimens from university and NIBIO greenhouse, which exhibited symptoms indicative of viral infection. Through a molecular screening process involving RNA extraction, cDNA synthesis, and RT-PCR using virus-specific primers, a mixed infection involving Kalanchoe mosaic virus (KMV), an unidentified polerovirus, and Broad bean wilt virus (BBWV) was confirmed. To further understand the etiology and transmission patterns of these viruses, as well as their individual effects on host plants, it was essential to isolate and subsequently reinfect begonia and other test plants with each virus separately. Different inoculation methods, such as sap inoculation, grafting, and aphid transmission, were employed to evaluate their effectiveness in virus transmission. Our results demonstrated successful single virus infections of KMV and BBWV through sap and grafting inoculations. However, attempts at polerovirus transmission with all the methods were unsuccessful. Moreover, aphid transmission using the green peach aphid proved unsuccessful to transfer any virus. Interestingly, the study unexpectedly found that the greenhouse potato aphid could carry the KMV virus to previously uninfected begonias, revealing a new vector that might transmit these viruses. The study discovered that using sap inoculation, especially through the roots, is an effective way to introduce viruses into begonias. This method successfully bypasses the issues caused by the plant's thick, acidic leaf sap. Additionally, a new buffer solution was created, greatly improving the success of sap inoculation for BBWV in both begonia isolates and other samples. This research provides critical insights into the transmission dynamics and management of viral infections in begonias, contributing to the broader understanding of plant-virus interactions and the development of effective control measures.
Authors
Tatiana Francischinelli Rittl Reidun Pommeresche Anders Johansen Håvard Steinshamn Hugh Riley Anne-Kristin LøesAbstract
Anaerobic digestion (AD) of animal manure generates renewable energy in the form of biogas. However, there is a gap in our understanding of the long-term impacts of AD-treated manure on soil attributes and crop productivity in comparison to untreated manure. To address this, a longterm field experiment was initiated in 2011 within a perennial grass-clover ley. The objective was to investigate the effects on key soil and crop parameters when slurry from organically managed dairy cows underwent AD. The results (2011-2021) indicated that while the application rate of manures influenced soil nutrient levels and pH, these parameters were unaffected by AD treatment. Higher slurry application rate (220 kg of total N ha-1year-1) led to a surplus of N, while deficits were observed in the untreated (non digested) control and the treatments with low application rates (110 kg of total N ha-1year1). Treatments were not limited by P. For K, there were deficitsin all treatments. Soil organic matter (SOM) concentrations decreased across all plots, especially in those with inherently high SOM levels. This decline in SOM was similar with both untreated (non-digested) slurry and anaerobically digested slurry, and there was no significant effect of application rate. The decline may be attributed to the initial high SOM content, prolonged drainage, and increasing temperatures due to climate change. Notably, both US and ADS demonstrated similar yields of grass-clover ley (2 cuts year-1) and green fodder, averaging 7.9 and 4.0 kg DM ha-1, respectively. Additionally, within the same production year the mean clover yields of the fertilized treatments did not differ from the control. In terms of crop yields and chemical soil characteristics, the long-term effects (over 10 years) of AD within an organic dairy cattle farming system were generally minor. The advantages of harvesting energy from slurry did not compromise the long-term productivity of grasslands or the soil chemical characteristics
Authors
Tatiana Francischinelli Rittl Lied, Geirmund Aker, Mari Ingvar Kvande Eva Brod Kari-Anne Kallerud LyngAbstract
The access to marine residual resources is large in Norway, yet its use in agriculture remains limited. Circulizer project aims to improve the circularity between the blue and green sector, by increasing the knowledge of the use of marine residues (i.e. fish sludge and fish silage) for biogas production and its effects on the fertilizer quality (digestate) and environment. While the quality of digestate from food waste and animal manure has been extensively studied, the impact of incorporating increasing proportions of new marine residual resources remains to be investigated. To be able to substitute mineral fertilizer with digestate derived from marine residues, farmers require knowledge of its nutrient composition and availability. In contrast, biogas plant operators need assurance of a market for both biogas and digestate before investing in new facilities. Circulizer will run lab and field scale experiments where the biogas process performance and digestate quality will be assessed. Expected outcomes are: (i) Enhancing the green transition and circularity of Norwegian food production by recycling valuable nutrients from fish production for agricultural use; (ii) Ensuring environmental safety by addressing concerns related to heavy metals and organic pollutants; (iii) Increasing the utilization of marine residual resources for biogas production; (iv) Supporting the growth of the fish farming industry in Norway by improving waste treatment and recycling options for unavoidable residual resources, thereby facilitating increased fish production and nutrient recycling
Authors
Maria Åsnes MoanAbstract
Bonitet er definert som overhøyden ved en gitt referansealder og brukes for å beskrive skogens potensial for å produsere tømmer. Bonitering, altså å bestemme boniteten, har utviklet seg fra feltbaserte metoder til metoder som benytter seg av punktskydata. Punktskydata fra flybåren laserskanning og bildematching har blitt brukt til å bonitere med den direkte og høydedifferensielle metoden. Disse metodene bruker overhøydeutviklingen over en kjent periode til å bonitere ved bruk av punktskydata fra minst to tidspunkt, dvs. multitemporale punktskydata. Den direkte metoden boniterer ved bruk av en prediksjonsmodell for bonitet med forklaringsvariabler beregnet fra punktskydata. Den høydedifferensielle metoden finner boniteten der forventet overhøydeutvikling passer best med den predikerte overhøydeutviklingen. Denne avhandlingen tok sikte på å forbedre metodene for bonitering med punktskydata og består av fire studier. Forstyrrelser kan gjøre et område uegnet for bonitering med punktskydata. Tidligere har man definert egnethet som områder uten negativ utvikling i overhøyde eller biomasse, men dette betyr ikke nødvendigvis at overhøydeutviklingen er uforstyrret. Den første studien i denne avhandlingen klassifiserte egnethet med variabler fra multitemporale laserdata. Egnethet var definert basert på feltregistrerte forstyrrelser hos dominerende trær. Resultatene viste at egnethet kunne klassifiseres med multitemporale laserdata, selv om definisjonene av egnethet i den studien var konservative ettersom ett dødt dominerende tre var nok til at prøveflaten ble klassifisert som uegnet. En tidsserie med laserdata kan forbedre nøyaktigheten til boniteringen sammenlignet med å bruke laserdata fra to påfølgende laserskanninger. Dette er fordi overhøydeutviklingen for en lengre periode vil bli representert. Den andre studien i denne avhandlingen brukte laserdata fra tre tidspunkt for å bonitere med den direkte og høydedifferensielle metoden. Prediksjonsfeilene var ikke statistisk signifikant forskjellig når man brukte laserdata fra hele tidsserien sammenlignet med å bruke laserdata fra to påfølgende tidspunkt, dvs. enten første og andre eller andre og tredje tidspunkt. Imidlertid økte andelen av området som var egnet for bonitering når hvilket som helst delsett av påfølgende tidspunkter i tidsserien kunne brukes, noe som ga en økt fleksibilitet til å unngå å perioder der det hadde vært en forstyrrelse. «Value of improved information» kan brukes til å vurdere nytteverdien av forskjellige boniteringsmetoder når beslutningstakeren har ulike mål for skogforvaltningen. Den tredje studien brukte stokastisk programmering for å beregne «value of improved information» ved bruk av den direkte og høydedifferensielle metoden med enten multitemporale laserdata eller laserdata og påfølgende bildematchingsdata. Resultatene viste at «value of improved information» var nærmest null og dermed best for den høydedifferensielle metoden i vårt studieområde. Den høydedifferensielle metoden kan potensielt brukes til å bonitere i ungskog. Den fjerde studien detekterte posisjonen til kvistkranser fra veldig tette punktskydata med en dyplæringsmodell og brukte detekterte kvistkranser til å bonitere med den høydedifferensielle metoden. Dette ga en «root mean square error» mellom 19,85 og 20,87%. En utfordring med bonitering i ungskog er at bonitetskurvene er brattere for lave aldre sammenlignet med høyere aldre, noe som resulterer i at feil i deteksjonen av kvistkranser har større konsekvenser for bestemmelsen av bonitet i ungskog. Denne avhandlingen har tatt for seg noen utfordringer og muligheter for bonitering med punktskydata. Likevel viste den første og fjerde studien at det er behov for mer forskning på hvordan man best kan definere egnethet og bonitere i ungskog.