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.
2026
Abstract
In Norway, agroclimatic zones (ACZs) are a valuable tool for national analyses in subject areas concerning the optimized management of agricultural land resources. However, current Norwegian ACZs have been criticized for having an outdated standard climate normal (1931–1960), a limited representation of the local climatic variation, a lack of important model parameters, and weak methodological documentation. Therefore, this paper presents new ACZs for Norway that address these weaknesses. The most significant methodological updates are the use of the standard climate normal of 1991–2020, additional weather data variables, the downscaling of weather data to 250 m hexagons, and the incorporation of phenological crop models for spring wheat, spring barley, and forage grass. The grass model was calibrated with the number of grass harvests at research stations, while the grain models were calibrated with subsidy claim data. The modeled zones for the three crops were combined into the general ACZs. Example maps of the crop zones and new ACZs for the selected regions and the whole country are presented. The new ACZs are more robust, agronomically relevant, and better aligned with the current climatic conditions in Norway. The deliberate exclusion of factors other than climate ensures the new ACZs’ national comparability and their applicability in policy development, land-use planning, climate adaptation, and agronomic assessments at the national scale.
Authors
Edward H. Cabezas-Garcia Yang Li Daniel Korir Jesse K. Gakige Stefan Muetzel César S. Pinares-Patiño Vibeke Lind Mutian Niu Claudia ArndtAbstract
No abstract has been registered
Authors
Thiago Inagaki Frederik Bøe Ievina Sturite Meike S. Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseAbstract
In high-latitude arable systems (63.9°N), short growing seasons and cold climates often constrain regenerative practices. This study investigates how cover crop (CC) diversity influences the synergy among root development, carbon (C) persistence, and nutrient (N and P) dynamics within a barley (Hordeum vulgare L.)-oat (Avena sativa) rotation. Over three years, we evaluated a gradient of CC intercropping complexity using a randomized complete block design. Treatments were: (1) Control (barley/oat without NPK), (2) Biochar-Fertilizer (barley/oat + NPK + 1.8 Mg ha-1 year-1 biochar), (3) Monocrop (barley/oat), (4) Ryegrass (barley + ryegrass), (5) Clover (barley + ryegrass + white/red clover), and (6) Chicory (barley + ryegrass + red clover + chicory + bird’s-foot trefoil). We quantified root biomass, soil organic matter (SOM) fractions, specifically Mineral-Associated Organic Matter (MAOM) and Particulate Organic Matter (POM), aggregate stability, nutrient stocks, and microbial abundance via qPCR. The CCs sown shortly after barley were successfully established, with an average biomass of 1525 kg/ha, without compromising cereal yields, thereby confirming their viability in Nordic climates. A central finding was that root development served as the primary driver of organo-mineral associations. Ryegrass- and Clover-based systems produced significantly higher root biomass, which correlated strongly (p < 0.01) with MAOM stocks and total P acquisition. These systems stored 12 Mg/ha more MAOM-C and 1.1 Mg/ha more MAOM-N than the control at 0-20 cm depth. The inclusion of diverse functional traits in the complex five-species mixture significantly improved soil physical structure, yielding higher aggregate stability and lower bulk density. While CCs accumulated approximately 7 kg P/ha, the diverse mix optimized nutrient availability, whereas simpler mixtures showed higher C:P ratios, suggesting potential microbial P immobilization. Microbial abundance was consistently higher in multi-species treatments, indicating a more active biological environment. Ongoing analysis integrates cereal physiological data, focusing on the photosynthetic efficiency of oats in response to cultivation? regimes. Our findings bridge the gap between root morphology, plant physiology, and long-term SOM persistence, providing a strategic framework for using functional crop traits to enhance soil resilience and nutrient efficiency in cold-climate regions.
Authors
Thiago Inagaki Frederik Bøe Ievina Sturite Meike Sophie Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseAbstract
High-latitude regions pose challenges for soil organic matter (SOM) sequestration and for improving soil fertility due to low temperatures, which shorten growing seasons and promote off-season nutrient leaching. Even long-term experiments on conservation practices have shown only modest increases in C storage. Nonetheless, persistent SOM fractions, such as mineral-associated organic matter (MAOM), have been shown to improve relatively quickly through conservation practices in temperate regions, which could be key in high-latitude regions. MAOM is an important SOM fraction not only for promoting carbon (C) storage but also for providing an available form of nitrogen (N) for plant nutrition. In this study, we show that, in Norwegian agriculture (63.9°N), MAOM (C and N) stocks improved only after three years of implementing cover crop systems that combined 1 to 4 cover crops with cereals (barley or oats) intercropped simultaneously (12 Mg ha-1 for C and 1.1 Mg ha-1 for N in the 0-20 cm layer more compared to unfertilized Control plots). Cover crops containing red and white clover and ryegrass efficiently increased the MAOM fraction in soil. An increase in root biomass and changes in root morphology were the primary factors linking cover crops to MAOM improvements in this field. In addition to benefits for SOM stocks, we recorded improvements in microbial abundance, soil structure, nutrient cycling, and cereal physiology. Our findings help to reframe MAOM as a bioavailable nutrient pool essential for soil health and nutrient cycling, which can be improved in the relatively short term through root development.
Abstract
Purpose Advanced remote sensing and imagery technology help to estimate variability in grass ley plant coverage (PC). Adjusted manure and fertiliser application rates can be derived according to this variability, by means of machine learning and advanced image processing. This study aimed to determine the effects of variable nitrogen (N) rate from manure and synthetic fertiliser application on a grass ley field experiment in southwestern Norway, thereby generating N rate recommendations. The effects on dry matter yield, N use efficiency, and forage nutritive value were determined. Methods A field experiment was conducted in 2022-2023 and repeated in 2023-2024, estimating PC using digital processing of autumn and spring aerial images to determine fertiliser rates. Three fixed and two variable manure and mineral N rates were applied in early spring and after the first and second cuts. Forage dry matter yield (FDMY) and agronomic N use efficiecy (AgNUE) were evaluated over two seasons. Results A low or variable N rate based on spring coverage led to FDMY and AgNUE comparable to high N rates. Spring and autumn coverage during the second season improved slurry application decisions, offering a valuable tool for grassland management. The N rate-response model effectively represented the nonlinear behaviour of FDMY, revealing a strong concave response to N rates, significant seasonal variations, and a notable flattening of the response in 2024. Predicted curves indicated that the most beneficial N application occurs in earlier cuts, as late-season applications showed diminished yield leverage under 2024 conditions. Conclusion Image analysis can effectively support variable-rate fertiliser recommendations for perennial grasslands, although such approaches only improved N usage in one of two years. Whilst variable-rate application (VRA) is resilient during constrained regrowth years, interannual weather variability and seasonal conditions significantly influenced N responsiveness, indicating the necessity for calibrating cover-based models to enhance nutrient management efficiency under varying climate conditions.
Abstract
Conference paper presenting rumen degradation and in vitro gas production characteristics of grass-clover pulp silage compared with conventional grass-clover silage.
Authors
Janicke Nordgreen Grete H. M. Jørgensen Cecilie Marie Mejdell Ruth C. Newberry Stephan Reber Kristin Opdal Seljetun Åsa Maria Olofsdotter Espmark Erik Georg Granquist Ingrid Olesen Sonal Patel Sokratis Ptochos Amin Sayyari Marco Vindas Tor Atle MoAbstract
VKM has assessed the welfare needs, welfare challenges, and mitigation measures for 27 exotic bird species kept as companion and hobby animals in Norway. VKM concludes that it is challenging to achieve good welfare for these exotic bird species in captivity. There is a high risk of poor welfare in these birds kept without conspecifics. Furthermore, inadequate housing lacking enrichment and without the possibility of free flying outdoors is detrimental to the welfare of all species. Feather clipping and hand-rearing are other high-risk factors, as is feeding a seed-based diet. VKM has also compiled an overview of mitigation measures.
Authors
Giovanni Peratoner Caren Pauler Manuel Schneider Vibeke Lind Andreas Klingler Andreas Schaumberger Enrico SturaroAbstract
No abstract has been registered
Authors
Trine Eggen Carl Einar Amundsen Robert Barneveld Aksel Bernhoft Barbara Alexandra Bukhvalova Gunnar Sundstøl Eriksen Belinda Flem Christiane Kruse Fæste Tron Øystein Gifstad Merete Grung Veronika Sele Kaja Helvik Skjærven Øystein Sæle Stefan Trapp Christian Vogelsang Håvard SteinshamnAbstract
This report presents a risk assessment of organic contaminants in sewage sludge and sewage-sludge-based products used on agricultural land in Norway, under current and alternative fertiliser regulations and management practices. It identifies a limited number of substances of concern for soil health, aquatic organisms, animal health, and human health, and provides a scientific basis for evaluating circular economy, organic fertilisers, and the safe recycling of bioresources in agriculture. Background and purpose The Norwegian fertiliser regulations was revised in 2025 to support reduced pollution, better utilisation of nutrients, fulfilment of international obligations, simplification, and facilitation of nutrient recycling. In Norway, 50 to 60 per cent of sewage sludge is used on agricultural land, compared with around 40 per cent in the EU. Norway has many small wastewater treatment plants and a long tradition of using treated sludge in agriculture. At the same time, incineration is less common in Norway than in many other European countries, partly because Norwegian wastewater treatment largely relies on chemical phosphorus precipitation (chemical separation of phosphorus). In recent years, new products based on sewage sludge have been developed, such as pellets, biochar and struvite (a fertiliser product recovered from wastewater that makes it possible to recycle phosphorus and nitrogen for agricultural use). At the same time, knowledge about organic contaminants in sewage sludge has increased. On this basis, the Norwegian Food Safety Authority asked VKM to assess the risks associated with organic contaminants in sewage sludge and sludge-based products. Terms of reference and scope VKM was tasked with identifying organic contaminants in sewage sludge and assessing which substances were relevant to include in the risk assessment. The assignment also covered products made from sludge, such as biochar, ash and struvite. Risks were to be assessed for the use of sludge on agricultural land over a period of up to 100 years. If current practice could lead to undesirable effects, alternative application rates and uses were also to be evaluated. In addition, less stringent rules for use in the cultivation of vegetables and on grassland used for mowing and grazing were to be assessed. The assessment covered possible effects on soil-dwelling organisms, aquatic organisms, livestock and humans. Combined effects of multiple substances were not assessed in detail. Methods and scenarios The risk assessment was based on data for more than 1,000 organic contaminants measured in Norwegian sewage sludge. For some pharmaceuticals that had not been analysed, levels were estimated using consumption data and modelling. Substances were prioritised based on occurrence, properties, degradation, mobility and toxicity. A model was developed to calculate how organic contaminants may accumulate and spread in soil, water and plants over time. The calculations were used to assess exposure for soil- and water-dwelling organisms, livestock and humans. The model accounted for climate and soil conditions in five regions in Norway. A wide range of scenarios for the use of sewage sludge and sludge-based products in the cultivation of cereals, potatoes, vegetables and grass were assessed. These included current practice, reduced application rates, use every ten years and annually, different intervals between application and cultivation or grazing, and the use of pellets, biochar, struvite and liquid digestate from sewage sludge. The effects of thermal hydrolysis were also assessed. Summary of main findings Norwegian monitoring data show that municipal sewage sludge contains many different organic contaminants, but levels vary widely between treatment plants and regions. The levels of several legacy pollutants, such as PCBs, PAHs and PBDEs, have decreased over time but are still present in sludge and remain relevant because they degrade slowly and can accumulate in the environment. PFAS are regularly detected, particularly PFOS and other long-chain PFAS. Pharmaceuticals and newer industrial chemicals often occur at low levels but with large variation. Several substances found at the highest concentrations are linked to cosmetics and personal care products. The different sludge-based products have different risk profiles. Pellets are expected to pose roughly the same or slightly lower risk than dewatered sludge. Struvite contains very low levels of organic contaminants and was consistently associated with low risk. Biochar is distinctive in that pyrolysis reduces many organic contaminants, but there is still uncertainty related to the possible formation of new compounds and how residues may be bound or released over time. For soil-dwelling organisms, the assessment showed that current practice may pose a long term risk for some substances. After quality assessment of the data, 19 organic substances showed potential risk, including certain pharmaceuticals, cosmetic-related substances, plastic related compounds, PAHs and PFOS. Lower application rates reduced risk but did not eliminate it. For some persistent substances, annual application could result in a higher cumulative load than application every ten years. For aquatic organisms, under current practice one substance exceeded the risk threshold, the pharmaceutical fenbendazole, but the assessment is uncertain. In scenarios with less stringent conditions or alternative uses, several substances were considered capable of posing a risk to the aquatic environment. For livestock, the calculations generally showed low levels of individual substances in feed rations. Risk was highest for grazing animals, as soil ingestion is an important exposure pathway, and with the use of liquid digestate from sewage sludge, direct intake may also contribute. Delayed grazing after application of products was found to reduce exposure. At the same time, some substances, particularly bisphenols and certain pharmaceuticals, are highlighted as relevant to animal health, and combined effects cannot be ruled out. For humans, current use of sewage sludge is generally assessed to pose relatively low risk to food safety for most of the substances examined. At the same time, an increase in organic contaminants in agricultural soil is undesirable. The report highlights PFAS, PCBs, dioxins, PAHs, PBDEs, siloxanes, bisphenol A, octocrylene and several pharmaceuticals as important for food safety, because dietary exposure to some of these substances is already considered undesirable or of concern. For individuals with high consumption of locally caught freshwater fish, exposure is generally assumed to be limited, but for some individuals it may be relevant. Main conclusion Norwegian data show that sewage sludge contains many organic contaminants, but levels vary widely. Most substances appear to pose low risk to soil-dwelling and aquatic organisms, and low health risk to livestock and humans. Some persistent substances may give rise to concern over time. Struvite was consistently associated with low risk, while pellets, biochar, sewage sludge and liquid digestate from sewage sludge have more complex risk profiles. For humans and livestock, risk is generally low under current practice, but certain groups of substances are undesirable because the overall burden is already high or of concern. The report concludes that some substances should be prioritised for further investigation and follow-up. In summary: VKM concludes that most organic contaminants in sewage sludge pose low risk, but that some organic contaminants may give rise to concern over time. This particularly applies to persistent substances that can accumulate in soil. The report therefore highlights the need for further investigation through the collection of more data and knowledge to support future risk assessments.
Abstract
The experiment aimed to investigate the effectiveness of a Monil virtual fence collar for small ruminants on mature Norwegian White ewes at the NIBIO Tjøtta station. The study aimed to evaluate the animals' learning ability and welfare, compare two auditory cues (Original vs. Modified; collar treatment), and examine the effects of wool (Shaved vs. Unshaved) on the efficacy of the virtual fence system. A total of 16 ewes were randomly assigned to two groups of 8, each equipped with one of the collars, and further divided based on wool treatment. Two mirrored training arenas were set up for the two groups. For two days, the collared animals had unrestricted access to graze the entire arena (VF-Off). This was followed by two days of restricted access to 2/3 of the arena using the virtual fence collars (VF-On). After the fourth day, the animals were switched to the other arena as a crossover design, and the sequence of VF-Off and VF-On was repeated. Data collected included position and cue logs from the virtual fence collars, heart rate monitors, and observation data gathered through three methods: Video Surveillance, Direct Observation Time Budget, and Pressure Marks Assessment. Our results indicate that the ewes were able to learn to avoid restricted zones effectively, relying more on auditory cues than on electrical cues. The virtual fence cueing imposed short-lived stress (acute stress), with both behavioral and physiological metrics returning to baseline levels within five minutes. Additionally, exclusively auditory cues resulted in less stress compared to cues associated with electrical stimulation. No indicators of chronic behavioral stress were observed. However, we found that the collars needed to move freely on the animals' necks to prevent pressure marks, suggesting that the ewes should be shaved around their necks before wearing the collars. While collar treatment showed no significant effects, wool treatment indicated that the shaved group was more compliant with the virtual fence system due to reduced insulation, which enhanced the effectiveness of electrical cues. During the deployment with the unshaved group, there were three instances in which the animals received an electrical cue that did not elicit the animal response, allowing for their “escape” over the virtual fence boundary. Therefore, equipping the virtual fence on shaved animals is paramount for enhancing the system's reliability. If the suggestion is followed, the system can effectively be used for sheep without compromising animal welfare.