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
Purpose: Rice production in paddy soil is important for food security, and nitrogen fertilisation is important to achieve high yields. Digestate, the organic rest from biogas production can be a good fertilizer, but relatively little is known about its use in paddy soil, which is investigated here. Method: Nitrogen transformations and rice growth in soil waterlogged and at field capacity after application of digestate and digestate products were assessed in a pot experiment. Nitrogen transformations and nitrous oxide (N2O) emissions with the same digestates were also assessed in an incubation. Results: One of the tested digestates had as good fertilizer effect as urea. Nitrogen transformations went mostly as expected under given water status, but digestates were more affected by waterlogging than urea. Some instability appeared about 10 days after fertilizer application. Then nitrite levels were high, responsive microbial populations peaked and N2O emissions started. Whilst emissions after mineral fertilizer application (urea) were not affected by waterlogging, emission after application of one of the examined digestate was high at field capacity but almost zero under waterlogging. N2O emissions from all other digestate and water treatments were also low. Conclusion: Digestates have great potential as organic fertilizers in rice production, but N2O emissions under aerobic soil conditions are of concern and warrants further investigation and mitigation strategy.
Authors
Gry Alfredsen Michael Altgen Mari S. Austigard Johan Mattsson Maria Nunez Lone Ross Sverre Aarseth Tunstad Andreas Treu Igor A. Yakovlev Nanna Bjerregaard PedersenAbstract
Abstract This study uses a novel combination of DNA metabarcoding, light microscopy, decay rating, moisture dynamics, and chemical analysis to investigate wood decay in cultural heritage cable car pylons in Svalbard. Uniform design but varying ages allowed analysis of time-dependent decay. Light microscopy revealed the use of both Picea abies and Pinus sylvestris . Decay progressed more rapidly near ground contact, influencing density, lignin, and holocellulose content, with lignin increasing over time. DNA metabarcoding and microscopy revealed dominant brown and soft rot fungi, with greater fungal diversity near ground level. Several new fungal species were identified for Svalbard and the polar regions. In the context of climate change, this highlights the global importance of monitoring fungal decay in wooden structures. The study emphasises the need for updated species lists and continuous monitoring, as new fungi may affect conservation strategies. The interdisciplinary method offers deeper insight into microbial interactions than single-method approaches.
Authors
Elena Arrigoni Ruairi Hafferty-Hay Pino-Raquel Bodas Liv Guri Velle Kerry Bradshaw Zeren Yang Amanda Cooper Tim Wilkinson Jeffrey G. Duckett Silvia Pressel Rachael Howlett Justin Moat Susan Zappala Martin I. Bidartondo Laura M. Suz Jill KowalAbstract
Heathlands are among the most iconic habitats in Northern Europe, with 20% of the world’s total area in the UK. Their wide, open landscape is dominated by low-growing Ericaceae shrubs and associated ericoid mycorrhizal (ErM) fungi on nutrient poor, acidic, dry or waterlogged, organic soils. ErM fungi enable N and phosphorus uptake by their plant hosts in exchange for carbon, playing a crucial role in nutrient cycling and contributing to carbon stocks. These fungi also form intimate associations with the rhizoids of several leafy liverworts, including the widespread heathland liverwort Cephaloziella divaricata. In the 20th Century, nitrogen (N) pollution alongside urbanisation and tree encroachment, have severely impacted heathlands, contributing to their sharp decline. The effects of N pollution on heathland vegetation are well documented, with useful indicators including lichens and bryophytes. However, little is known about how the soil microbiome, including mycorrhizal-forming fungi, is impacted by N pollution. Also lacking is understanding of how heathland might recover; with N pollution now declining across parts of Europe, there is demand from managers and policymakers for novel indicators of heathland recovery. Our research investigates responses of ErM fungi to, and recovery from N pollution, and evaluates their suitability as recovery indicators. 18In 2021, we reinstated a dormant experiment in a dry heathland at Thursley National Nature Reserve (Surrey, UK) where N additions ceased in 2010. Results showed lingering effects of N additions on heather vegetation, moss ground cover, lichen communities, soil chemistry and soil fungal communities, while a negative trend was observed in root ErM colonisation in N-treated plots. In 2023, we established thirty new plots, 15 fertilised with 30 kg/ha of ammonium nitrate (NH4NO3), and 15 as controls. To account for plant age, 20 plots were located within mature C. vulgaris stands, and 10 on pioneer vegetation (wildfires occurred in 2006 and 2020, respectively). Combining eDNA techniques and microscopy, we are monitoring ErM root and rhizoid colonisation in C. vulgaris and C. divaricata respectfully, diversity of fungal communities in roots and soil, and soil fungal biomass. A lichen survey was conducted to assess differences in postfire recovery. Vegetation structure and biomass changes are monitored with LiDAR, RGB and multispectral drone imaging to develop a complementary carbon calculation method. We also sampled six coastal heathlands in Norway, along a south-north N deposition gradient (1-6 kg N/ha/yr), and a comparable wet heathland at Thursley (13 kg N/ha/yr) to investigate potential mycorrhizal indicators of healthy heathlands below the N critical load. Preliminary results show ErM fungi are more diverse than expected, with ongoing analyses linking root colonisation to N deposition and climate data to understand heathland recovery and identify potential nitrophilic and nitrophobic ErM fungi as recovery indicators.
Abstract
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.
Abstract
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.
Abstract
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.
Authors
Lampros LamprinakisAbstract
No abstract has been registered
Authors
Tannaz Alizadeh AshrafiAbstract
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.
Authors
Jørgen A.B. MølmannAbstract
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.
Abstract
No abstract has been registered