Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2025
Sammendrag
In this study the effects of growing annual and perennial plant species in five growing media blends; one peat-based, two peat-reduced and two peat-free. Three main components were used in the blends: sphagnum peat (P-Soil (PS), Wood fiber substrate (WFS), Peat reduced blend (PRB)), coarse wood fiber (Fibergrow®) of Norway spruce (Picea abiens) (WFS, PRB, Circle soil (Circle), PFB) and garden/park waste-based compost (Circle, PRB, PFB). The peat-based reference (P-Soil) contained 10 vol.% composted bark in addition to sphagnum peat. pH in the blends ranged from 5.1 to 6.4. Both annual and perennial plants were tested in the five blends, and large differences in growth and vitality of plants grown in the different blends were observed. The performance of most plant species grown in Circle, PRB and PFB was characterized as satisfactory, while P-Soil gave the best results and was used as reference as it is commonly used in the plant nursery. Plants grown in WFS showed generally weak growth and the plant growth was characterized as unsatisfactory. However, WFS and PRB performed satisfactory to seedlings of Rhododentron uniflorum, while Circle and PFB failed to give satisfactory growth of rhododendron seedlings. Although all blends were basic fertilized with different types of compound mineral fertilizers, chemical analyses showed significantly lower concentrations of CAT-soluble plant nutrients in WFS compared to the other blends. N-immobilization during storage in plastic bags may have occurred for WFS, which has very high C/N-ratio. In the blends with compost and Fibergrow® the expected levels of mineral N were found, and no N-immobilization occurred. In the blends with compost almost all mineral N was present as nitrate-N, while ammonium-N dominated in P-Soil. There were no large differences in root development between the five blends, and the root growth in WFS was good despite significantly smaller plants than in the other blends.
Sammendrag
In this article we show benefits of quota flexibility in a single-stock fishery model where one of the firms is allowed to behave strategically in the trading of quotas while other firms in the fishery are price takers. The ex-vessel price for fish is assumed constant. Quota flexibility is implemented through a settlement at the end of each regulation period. In that settlement firms having unused quotas are compensated by a subsidy, while those who have quota shortfalls are obligated to pay a tax. For the same deviation the tax is higher than the reward. Former literature shows that market power under a traditional ITQ system can lead to inefficiencies. However, losses due to market power can be subdued when quotas are more flexible. A simple argument to account for this view is that the competitive fringe of firms in the flexible case have the option to make use of the tax/reward system. Thus, rather than being exploited by the price manipulating firm the competitive fringe might find it better to deviate from the 1:1 “quota — realized catches”- relationship that characterizes competitive equilibrium.
Sammendrag
In this article we show benefits of quota flexibility in a single-stock fishery model where one of the firms is allowed to behave strategically in the trading of quotas while other firms in the fishery are price takers. The ex-vessel price for fish is assumed constant. Quota flexibility is implemented through a settlement at the end of each regulation period. In that settlement firms having unused quotas are compensated by a subsidy, while those who have quota shortfalls are obligated to pay a tax. For the same deviation the tax is higher than the reward. Former literature shows that market power under a traditional ITQ system can lead to inefficiencies. However, losses due to market power can be subdued when quotas are more flexible. A simple argument to account for this view is that the competitive fringe of firms in the flexible case have the option to make use of the tax/reward system. Thus, rather than being exploited by the price manipulating firm the competitive fringe might find it better to deviate from the 1:1 “quota — realized catches”- relationship that characterizes competitive equilibrium.
Forfattere
Lampros LamprinakisSammendrag
Det er ikke registrert sammendrag
Forfattere
Tannaz Alizadeh AshrafiSammendrag
Bottom trawling is highly reliant on fossil fuel combustion due to the energy demands of towing heavy nets across the seabed and long-distance steaming. Consequently, it significantly contributes to greenhouse gas emissions and global warming. The volume of CO2 emissions released is influenced by fishers’ harvesting behaviors, shaped by the bioeconomic conditions of the fishery, including fish availability at various locations, distances to home ports, market dynamics, fishing quotas, and regulatory frameworks. In response to increasing concerns over climate change, regulators have proposed fuel taxation as a mitigation strategy. This policy is expected to drive trawlers to adopt new fishing strategies to maintain maximum expected profits while operating under quota management constraints. To explore this dynamic, we developed a system dynamics model to examine how fuel taxation impacts the profit-maximizing harvest patterns of the Norwegian cod trawl fleet. Specifically, we investigate how decisions regarding when, where, and how much cod to fish per trip are influenced by such taxation. Our analysis utilizes haul-by-haul fishing data from 32 Norwegian cod trawlers, spanning the period 2011–2023. Additionally, we assess the effectiveness of fuel taxation in reducing CO2 emissions from the trawl fleet. The findings provide valuable insights into the interplay between regulatory measures and fishers' behavior, with detailed discussions on relevant policy implications.
Forfattere
Jørgen A.B. MølmannSammendrag
Potato with origins from temperate/alpine regions of South America is well suited for agricultural production in the cool climates at high latitudes in Greenland, Iceland, Faroe Islands and northern Fennoscandia. Here, the importance of potato as a staple crop is likely to increase in the future due to global warming. Potentially contributing to a larger share in food production from the north. As well as providing local food security under the risks of unstable geopolitics or natural disasters. Earlier snowmelt and ground thaw extending the growth season within the Midnight Sun period, and a larger accumulated degree day sum is likely to improve production at high latitudes. We have studied the influence of temperature on the minimum light requirement for potato growth under Arctic day lengths. Our results show that the radiation required for high yields increases as temperatures decrease below the optimum for tuber growth. On the other hand, at increasing temperatures the requirement for high irradiance decreases. This means that potato plants may utilize the very long daily photosynthesis periods more efficiently under warmer temperatures at high latitudes in the future. Thus, resulting in potential higher yields and increased profitability for northern potato producers. The latter may counteract some of the current logistical challenges for the potato industry in the high north. This together with agricultural policies centered on self-sufficiency can give cause for optimism among potato producers at high latitudes.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Tannaz Alizadeh AshrafiSammendrag
Det er ikke registrert sammendrag
Forfattere
Jørgen A.B. MølmannSammendrag
Omvisning med orientering om potetforsøk ved BIologisk klimalaboratorium i Tromsø
Forfattere
Helge BerglannSammendrag
Det er ikke registrert sammendrag