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.
2023
Abstract
Salmon-lice have the potential to change the behaviour and growth of their salmonid host species. Here, the baseline infection levels of salmon-lice of post-smolts (n = 815) and veteran migrants (n = 875) of sea-run Arctic charr (Salvelinus alpinus Linnaeus, 1758) were monitored over two successive years in a sub-Arctic Norwegian fjord without farming of salmonids. All Arctic charr were collected after the sea-migration period from a trap placed in the river, ascending to their overwintering freshwater habitat (Lake Laksvatn). The sea-lice infection showed a stable infection across the 2 years while increasing through the migration period and with the size of the wild sea-run Arctic charr. The prevalence of sea-lice infection was intermediate to high, and the intensities of sea-lice infections observed were generally modest, although some individuals had high infections. The relatively high infection of salmon-lice highlights the potential detrimental effects these parasites can have at both the individual and population level of such endangered sub-Arctic life-history strategies. A comparative study should be performed in fjords with aquaculture activity as focal points for salmon-lice, to investigate the impact farming have on sea-run Arctic charr populations.
Authors
Christian Oliver Ewald Jelena Hadina Erik Haugom Gudbrand Lien Ståle Størdal Muhammad YahyaAbstract
In this paper we examine how sensitive Value-at-Risk (VaR) forecasts based on simple linear quantile regressions are to the sampling frequency used to calculate realized volatility. We use sampling frequencies from one to 108 min for ICE Brent Crude Oil futures and test the out-of-sample performance of a set of quantile regression models using formal coverage tests. The results show that a one-factor model performs exceptionally well for most sampling frequencies used to calculate realized volatility. In comparison with the well-known Heterogeneous Auto-regressive Model of Realized Volatility (HAR-RV) and a quantile regression version of the HAR model (HAR-QREG), we also find that the one-factor model is much less sensitive to the sampling frequency used to calculate realized volatility.
Authors
Gry Alfredsen Lone Ross Mari Sand Austigard Johan Mattsson Anne Cathrine Flyen Nanna BjerregaardAbstract
This report is a documentation of the field data collection and sampling at Svalbard in 2022 within the project ArcticAlpineDecay. The sampling methods are described and for each object sampling was performed documentation is provided, incl. location, Askeladden ID, map coordinate, photo documentation and illustration of sampling. Compilation of the results from the project will be published in peer review journals and in a final report from the project.
Abstract
Despite newly approved lucerne cultivars, this has not led to increased use of this legume in high-latitude agriculture. Challenges with inoculation by Rhizobium meliloti have been identified as a bottleneck to adaptation. Here we tested inoculation sources (ISs) with soil types and cultivars in pot and field experiments. During a one-year outdoor pot experiment, we tested the impact of IS (wet peat slurry and Nitragin Gold dry inoculation) and three soil types (sand, sandy silt and /peat soil) on nodule development, shoot and root growth and winter survival of one hybrid lucerne cultivar (‘Ludvig’). The pot experiment revealed that dry inoculation led to significant better plant growth, flower and nodule development as well as plant regrowth after winter survival. Peat soil appeared as the best growth medium and silty soil limited inoculation efficiencies. In field trials at two locations differing in soil characteristics using similar ISs, and three hybrid lucerne cultivars (‘Lavo’, ‘Live’ and ‘Lotte’) biomass yield during two ley years showed site as well as cultivar differences. Such environmental interactions in the field trials justify the use of adapted cultivars, and dry inoculation should be recommended for practical use replacing peat slurry inoculation.
Authors
Karin Juul Hesselsøe Anne Friederike Borchert Trygve S. Aamlid Bjarni Hannesson Per Rasmussen Karin Normann Tatsiana Espevig Michelle DaCosta Eric Watkins Andrew Hollman Jørgen Hornslien Trond Olav Pettersen Pia Heltoft ThomsenAbstract
The objective of SCANGREEN 2019-22 was to find species, varieties and seed blends/mixtures of Agrostis, Festuca, Poa and Lolium that are suited for pesticide-free management of putting greens in the two major climatic zones of the Nordic countries and in the northern USA. The four test sites in the Nordic countries were Reykjavik GC, Iceland and NIBIO Apelsvoll in the the northern zone, and NIBIO Landvik, Norway and Smørum GC, Denmark in the southern zone. The two US test sites were located at Troll Turfgrass Research Facility in Massachusetts and at University of Minnesota. The trials included 30 candidate varieties representing eight different species and subspecies from 13 different seed companies/representatives, and three seed mixtures of red fescue and colonial and creeping bentgrass, a seed mixture of creeping bentgrass and perennial ryegrass and a seed blend of red fescue. Monthly evaluations of overall impression, tiller density, winter hardiness, disease and weed coverage etc., were done from three weeks after sowing in June-September 2019 until October 2022. The trial at Smørum GC was established in May 2021. The trials were established according to a split-plot design with three blocks (replicates), species on main plots and varieties on subplots. The experimental greens were mown three times per week – Monday, Wednesday, and Friday and deficit-irrigated to 80% of field capacity three to four times per week in periods without sufficient natural rainfall. Fertilizer (mean N–P–K ratio, 100–22–74) was given as completely balanced compound fertilizers every second week. Each experimental green was divided in different management levels: High and low fertilizer rate and high and low mowing. The two fertilizer rates were 10 and 17 g N m−2 yr−1 and the two mowing heights were 3 and 5 mm. Mixtures were managed at both regimes. There was no use of pesticides or plant growth regulators in any of the trials.
Authors
Karin Juul Hesselsøe Anne Friederike Borchert Trygve S. Aamlid Bjarni Hannesson Per Rasmussen Karin Normann Tatsiana Espevig Michelle DaCosta Eric Watkins Andrew Hollman Jørgen Hornslien Trond Olav Pettersen Pia Heltoft ThomsenAbstract
No abstract has been registered
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Authors
Bente FøreidAbstract
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No abstract has been registered