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.
2026
Forfattere
Thiago Inagaki Frederik Bøe Ievina Sturite Meike S. Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseSammendrag
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.
Forfattere
Thiago Inagaki Frederik Bøe Ievina Sturite Meike Sophie Bärmann Franziska Bucka Alice Budai Anders Aas Daniel RasseSammendrag
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.
Forfattere
Ying Zhao Li Guo Jian Liu Jie Xue Jinzhao Liu Yingkai Chen Xinyan Cai Kenneth C Carroll Esteban Jobbagy Steven P Loheide Kathleen M B Boomer Yanping LiSammendrag
Meeting rising food demand under intensifying climate variability, soil degradation, and groundwater decline requires agriculture to produce more with less freshwater. We advance critical zone agrohydrology (CZA) as a unifying framework that treats agricultural landscapes as human-managed critical zones—coupled systems extending from canopy to bedrock and operating from seasons to decades. CZA is organized around the four deeps (deep time, deep depth, deep coupling, and deep practice) and operationalized through a 5M cycle of measuring, mapping, monitoring, modeling, and managing. This perspective expands conventional agrohydrology by accounting for long-term soil change, subsurface storage and flow, biogeochemical feedbacks, and human decision-making, thereby linking field efficiency with basin sufficiency. We illustrate implications for multifunctional soil management, nutrient-loss control, salinity rehabilitation, drought resilience, managed aquifer recharge, and cross-scale governance. By reframing agriculture as a potential contributor to aquifer stability, water quality, carbon storage, biodiversity, and durable productivity, CZA offers a practical pathway toward more resilient and basin-aware agricultural water management.
Sammendrag
Trifluoreddiksyre (TFA) er en persistent ultrakort PFAS-forbindelse som blir gjenfunnet i økende konsentrasjoner i drikkevann og mat både internasjonalt og i Norge. Det er mange kilder som kan bidra med tilførsler av TFA, men atmosfærisk nedbrytning av fluorerte kjølegasser samt nedbrytning av PFAS-baserte (CCF3) plantevernmidler brukt i jordbruk, vurderes som de viktigste. Denne rapporten presenterer TFAkonsentrasjoner målt i Skuterudbekken i 2025 og begynnelsen av 2026. Årlig tap av TFA fra JOVA-feltet Skuterud (4489 daa) ble beregnet til 3,3 kg. Det største tapet skjedde under større flommer høsten 2025, og korrelerte godt med utvasking av nitrat. Tilsvarende som for nitrat antas den største utvaskingen av TFA fra dyrka jord å skje via grøftevann. Data fra store nedbørfelt dominert av skog i Østlandsområdet kan indikere at TFA tilført med nedbør gir en «bakgrunnskonsentrasjon» på ca. 200 ng/l. I Skuterudbekken var midlere TFAverdi for 23 prøver på 1083 ng/l. Tallene kan indikere at bruk av CCF3-plantevernmidler kan forklare mer enn 80 % av årlig utvasking av TFA fra Skuterudfeltet, mens nedbørtilført TFA utgjør mindre enn 20 %. Kloakkslam kan være en ikke kvantifiserbar kilde til TFA i nedbørfeltet. Feltet er dominert av korndyrking på marin jord, og har 61 % jordbruksareal, 29 % skog og 10 % annet areal. Utvaskingen av TFA fra nedbørfeltet viste godt samsvar med TFA-ekvivalenter i anvendte CCF3-plantevernmidler, som har vist en årsvariasjon mellom 1,6 og 5,6 kg TFA per år, og et snitt på 3,8 kg. En del av tilført TFA vil fjernes med avling i form av korn og presset halm, eller annen avling. I tillegg til TFA ble det av og til påvist to andre ultrakorte PFAS-forbindelser; perfluorpropionsyre og trifluor metansulfonsyre, som antas å være metabolitter i samme nedbrytningsforløp.
Forfattere
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 SteinshamnSammendrag
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.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Etter utbyggingen av E18 Arendal-Tvedestrand har det vært stort søkelys på forekomst av sulfidholdige bergarter som ble avdekket under anleggsarbeidet, og bekymring for at veifyllinger og steinmasser vil kunne gi sur avrenning og giftige konsentrasjoner av metaller. Som en del av tiltaksplanen er det, for å avbøte sulfidoksideringseffekter, tilført skjellsand til disse deponiene. NIBIO tok over miljøovervåkningen høsten 2024. Denne rapporten vurderer tilstand og utvikling for berørte vassdrag på relevante parametere for sulfidoksideringseffekter seks år inn i driftsfasen for veistrekningen. Alle eksisterende data med relevans for miljøovervåkningen er benyttet. I store trekk kan man si at de avbøtende tiltakene har hatt positiv effekt på forsuringsparametere i vassdragene, men også medført økt pH, ANC samt økt innehold av alle hovedioner som igjen gir økt konduktivitet. Konsentrasjon av hovedioner og konduktivitet synes imidlertid å ha vært avtakende de siste årene. I tre av de seks vassdragene vurderes det at tilstand og trender er gode for relevante parametere, og overvåkningen kan avsluttes/nedskaleres. I de øvrige vassdragene er det enten noe påvirkning på, usikker tilstand eller trend for en eller flere parametere.
Sammendrag
Det har vært bekymring for at økt tilførsel av ioner, særlig knyttet til deponier ved Grenstøl, kan føre til akkumulering av hovedioner i bunnvannet i Vennevann og gi en permanent påvirkning på innsjøens sirkulasjonsforhold. I denne rapporten presenteres resultater fra miljøovervåkning gjennomført i Vennevann høsten 2024 og i 2025, basert på vertikale profiler, vannkjemiske analyser og undersøkelser av dyreplankton. Resultatene viser tydelige sesongmessige variasjoner i fysiske og kjemiske forhold, med perioder med stabil lagdeling, men uten tegn til permanent isolasjon av bunnvannet. Oksygen ble registrert i hele vannsøylen ved alle måletidspunkter, og det er ikke grunnlag for å vurdere innsjøen som meromiktisk. Konduktiviteten i bunnvannet ligger på nivå med tidligere undersøkelser, og det er ikke påvist tiltagende akkumulering av hovedioner over tid. Sulfat viste avtakende konsentrasjoner sammenlignet med tidligere målinger. Dyreplanktonundersøkelsene viser sesongmessige endringer, men uten indikasjoner på varige strukturelle endringer i samfunnet. Samlet sett gir undersøkelsene ikke indikasjoner på forverring av tilstanden i Vennevann, men understreker behovet for videre overvåking for å følge utviklingen over tid. Resultater fra profilmåling og vannprøver gjennomført i Vålevann i april 2025 viste at innsjøen sirkulerer som forventet og tilstanden er uforandret fra 2022
Sammendrag
Rapporten vurderer hvordan byggingen og driften av den nye E18-strekningen mellom Tvedestrand og Arendal har påvirket vannmiljøet i bekker og vassdrag langs veien. Veien ble åpnet 2. juli 2019 og overvåkningen har blitt gjennomført før, under, og etter anleggsperioden med vannprøvetaking og undersøkelser av biologiske kvalitetselementer. NIBIO overtok miljøovervåkningen høsten 2024. Dagens overvåkningsprogram omfatter 24 lokaliteter i 7 vassdrag som har vist ulik grad av anleggspåvirkning. Dagens vannkvalitet og økologiske tilstand varierer, men generelt viste resultatene økt pH, ANC, basekationer og sulfat i berørte vassdrag. I det aktuelle måleområdet antas imidlertid ikke disse endringene å ha noen negative effekter på tilstanden i vassdragene. Overvåkningen har vist at labilt aluminium, som er giftig for fisk, generelt sett har blitt redusert i overvåkningsperioden. Partikkelnivået er generelt nå som ved forundersøkelsene. Det samme gjelder for nitrogen, nitrat og ammonium for de aller fleste lokalitetene. Metallkonsentrasjonene er gode i hovedvassdragene. Enkelte sidebekker har fortsatt forhøyede metallverdier, men flesteparten viser «god» tilstand eller samme tilstand som ved forundersøkelsene. Fem år inn i driftsfasen er også den økologiske tilstanden tilbake til nivåer tilsvarende forundersøkelsene, men i noen av sidebekkene er tilstanden fortsatt noe dårligere for enkelte kvalitetselement. I flere av lokalitetene der tilstanden er tilbake til «førtilstand» kan overvåkningen avsluttes etter 2026. Lokalitetene som mottar avrenning fra deponier med sulfidholdig berg bør til gjengjeld overvåkes videre.
Sammendrag
This study quantified field-scale nitrogen (N) and phosphorus (P) removal by crop harvests, balances, and use efficiencies in 14 grass fields in the Timebekken catchment. Measurements of grass yields, nutrient concentrations, manure composition, and soil properties across multiple fields and farms were combined with survey data. Results showed large variation across farms and fields in day matter yield, nutrient inputs, removals, balances, and use efficiencies. Annual dry matter yield ranged 6,830–12,800 kg ha-1 (mean 9,010 kg ha-1) in 2024 and 7,480–12,130 kg ha⁻¹ (mean 9,800 kg ha⁻¹) in 2025. In 2024, nutrient inputs as mineral fertilizers and manure ranged 169–362 kg N ha⁻¹ (mean 240 kg ha⁻¹) and 23–57 kg P ha⁻¹ (mean 40 kg ha⁻¹). Corresponding nutrient removal ranged 150–303 kg N ha⁻¹ (mean 220 kg ha⁻¹) and 22–40 kg P ha⁻¹ (mean 29 kg ha⁻¹). Nutrient balances ranged from −111 to +182 kg ha⁻¹ (+14 kg ha⁻¹) for N and from −14 to +35 kg ha⁻¹ (12 kg ha⁻¹) for P. Nutrient use efficiency (input∕removal) ranged 50%–166% (mean 100%) for N and 38%–160% (mean 80%) for P. Overall, results indicate consistent management within farms but clear differences between farms, and therefore substantial potential for improving fertilizer and manure precision while maintaining yields. Phosphorus yield exceeded 27 kg ha-1 in several fields, in some 35 kg ha-1, which are the maximal allowed fertilizer limits from 2033. This substantiates farmers’ concerns about these limits being too low, yet average P inputs still exceeded crop demand. Despite lower topsoil P-AL in 2023 than in 2005, soil P status remained high, likely sustaining yields under stricter P limits. Elevated subsoil P highlights long-term loss risks and the need for targeted mitigation measures in hotspot areas. The study also calls for more monitoring of manure nutrients, yields, and soil P properties.