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
The background for this study is the limitations of the conventional approach of using deforestation area multiplied by biomass densities or emission factors. We demonstrated how TanDEM-X and GEDI data can be combined to estimate forest Above Ground Biomass (AGB) change at the national scale for Tanzania. The results can be further recalculated to estimate CO2 emissions and removals from the forest. We used repeated short wavelength, InSAR DEMs from TanDEM-X to derive changes in forest canopy height and combined this with GEDI data to convert such height changes to AGB changes. We estimated AGB change during 2012–2019 to be −2.96 ± 2.44 MT per year. This result cannot be validated, because the true value is unknown. However, we corroborated the results by comparing with other approaches, other datasets, and the results of other studies. In conclusion, TanDEM-X and GEDI can be combined to derive reliable temporal change in AGB at large scales such as a country. An important advantage of the method is that it is not required to have a representative field inventory plot network nor a full coverage DTM. A limitation for applying this method now is the lack of frequent and systematic InSAR elevation data.
Abstract
European livestock sectors rely heavily on imported protein feeds, presenting challenges regarding sustainability and supply security. Green biorefineries (GBR) represent a local alternative where protein concentrates are extracted from grassland crops, but the environmental performance of these systems depends on feedstock cultivation practices. This study combined field trials and life cycle assessment (LCA) to quantify how nitrogen (N) fertilization rates, clover inclusion rates, and feedstock management (fresh vs. ensiled) affect dry matter (DM) and crude protein (CP) biomass yields, as well as subsequent climate impact, and agricultural land use of GBR products. The results reveal that N fertilization during cultivation of feedstock biomass plays a critical role in the climate impact of green biorefining, and that including legumes enhances GBR sustainability. Increasing N fertilization from 0 to 240 kg N ha−1 in red clover–grass swards increased DM and CP biomass yields but also increased soil N₂O emissions and upstream fertilizer burdens. Under no N fertilizer treatment, biological N fixation supported high yields, resulting in the lowest net climate footprint in the ensuing LCA of the GBR process. However, this treatment also required around 60 % more land than the high N treatment. Processing ensiled feedstock further reduced the climate impact compared to fresh biomass by retaining more CP in the liquid fraction and eliminating several biorefinery steps. However, this benefit in this case was linked to the use of the liquid phase rather than ensiling itself, and similar outcomes could be achieved with fresh biomass if processed accordingly and used immediately after production. Future work must expand system boundaries to include transport, storage, and animal-feeding stages, and develop farm-level strategies that align GBR practices with regional conditions.
Abstract
Nitrogen (N) management is one of the main factors enhancing potato productivity and promoting sustainable agricultural practices. The Nitrogen Nutrition Index (NNI, obtained as the ratio of actual plant N, to the critical plant N concentration) is widely applied to assess the N status of various crops. Traditionally, NNI is calculated using field data, but remote sensing (RS) technologies can offer more rapidly and timely assessment of the spatiotemporal (within field) variability of this index. This study employs multispectral data acquired via Unmanned Aerial Vehicle (UAV) and machine learning (ML) models to estimate potato NNI. A Bayesian hierarchical partially pooled method was fitted to a three-year f ield experiment in Denmark and extensive ground-based potato datasets to model the critical nitrogen dilution curve (CNDC) and calculate the NNI. Multispectral UAV data were processed to extract four spectral bands and calculate several vegetation indices, which were used as predictors to train and test six ML models: Linear regression, support vector machines, gaussian process regression, stepwise linear regression, ensemble trees and neural networks. Among the compared models, gaussian process regression outperformed, showing R 2 equal to 0.83 and a RMSE of 0.10 and providing accurate NNI predictions, comparable to ground-based Bayesian estimates. The variability of the NNI was analyzed over the seasons using 28 NNI maps derived from UAV surveys at spatial resolution of 0.04–0.09 m/pixel, capturing spatial variations in crop N status over time. The proposed framework, designed for NNI prediction at the intra-field scale, has the potential to be adapted to different environments and crops. The framework can support practical decisions for precision N management, reducing the environmental impact of potato cultivations and enhancing sustainability.
Abstract
EMF significantly enhance conifer growth under diverse experimental conditions. EMF effects on conifer stress resistance were not statistically significant. Field studies on EMF-conifer interactions remain scarce and needed.
Abstract
Understanding the influence of stand structures generated by silvicultural treatments on light conditions is essential for tree regeneration, in particular of light demanding species such as Quercus petraea. Many past studies have quantified average light levels resulting from different types of regeneration harvests. Here, we analysed the impact of regeneration cuts on light heterogeneity, which may be important for competition among regenerating tree species and understorey. To this purpose, we investigated radiation levels and patterns in 57 stands originating from shelterwood harvesting of varying density, and 51 canopy gaps of different sizes in even-aged mature oak forests. Understorey radiation levels were quantified as indirect (ISF), direct (DSF), and total site factor (TSF) at systematically placed sample points. In shelterwoods, strong relationships occurred between ISF, DSF, and TSF and both canopy cover and stand basal area, suggesting that these metrics are suitable indicators of light conditions. In gaps, strong relationships existed between their diameter, area, height of edge trees and average ISF, DSF, and TSF. In gaps > 0.1 ha (in stands of ca. 30 m height), spatial heterogeneity of radiation exceeded that of shelterwoods, suitable to regenerate species with different light requirements. In contrast, shelterwoods provide uniform light conditions corresponding to the current requirements of the prevailing regeneration over large areas. Therefore, shelterwood harvesting is more suitable for regeneration of even-aged oak-dominated stands, whereas gaps are more appropriate for stands where sessile oak is admixed in form of single trees or groups and shall remain an admixed species.
Abstract
Ascospore release by the European apple canker fungus Neonectria ditissima was examined by means of continuously running spore traps mounted over detached segments of apple tree branches with cankers habouring maturing and ripe perithecia, or placed within tree rows in apple orchards. Records began in autumn 2017 and continued for nearly 3 years at two locations in Norway, and for five autumn to late spring periods at two locations in the Lower Elbe region of northern Germany. In northern Germany, the first ascospore releases were recorded during or after autumnal leaf fall, whilst major peaks occurred from March to May. In Norway spore discharge began in spring with a major peak, continued through the summer and autumn, and paused in mid-winter. These observations indicate that in northern Germany, ascospores are less likely to contribute to fruit and leaf scar infections than in Norway. Furthermore, ascospore discharge events in spring, which were recorded in all sampling years at all sites, were associated with the same rain events as those of the apple scab fungus Venturia inaequalis, and would have been covered by intensive fungicide sprays. For northern Germany, these results indicate a shift in major ascospore release peaks from autumn towards spring as compared to previous data collected some 50 years ago.
Authors
Tomáš Hlásny Michaela Perunová Roman Modlinger Max Blake Gediminas Brazaitis György Csóka Maarten de Groot Mihai-Leonard Duduman Massimo Faccoli Margarita Georgieva Georgi Georgiev Wojciech Grodzki Henrik Hartmann Anikó Hirka Gernot Hoch Hervé Jactel Mats Jonsell Marija Kolšek Paal Krokene Markus Melin Slobodan Milanović Bjørn Økland Milan Pernek Gilles San Martin Martin Schroeder Rupert Seidl Jozef Vakula Tiina YliojaAbstract
No abstract has been registered
Abstract
Nature-based solutions (NBS) have been broadly adopted to strengthen water and wastewater sanitation by effectively removing microbial pollutants and limiting significant health risks to aquatic environments and humans. However, temporal variations of pathogen removal efficiencies in NBS and the specific link with faecal pollutants remain understudied. In this study, a Norwegian urban NBS operating as a nature-based treatment system (NBTS) for water purification was monitored on pathogen removal capacities and faecal source tracking through a 1-year study. Applying coupled molecular analyses, i.e., pathogen molecular detection and genetic microbial source tracking, enabled the systemic assessment of this NBTS’s remediation performance while unveiling the intrinsic link between pathogen prevalence and the faecal pollution sources. Notably, the system exhibited stronger pathogen attenuation activity on Enterococcus faecalis, Salmonella enterica serovar Typhimurium, Clostridium perfringens, and Legionella pneumophila (linked closely to human origin in the studied NBTS) than Shigella species and Giardia lamblia sourced mainly from animals. Moreover, the studied system displayed temporal dynamics of its functioning. As such, more fluctuations often occurred in cold months than in the warm period and under varying impacts of measured environmental conditions (i.e., water temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, salinity, and oxidation reduction potential). Collectively, the findings of this study consolidate the functional potential of NBS in combating the microbial pollution that results specifically from waterborne enteric pathogens in a tight link with faecal contamination. The disclosed performance seasonality also calls for extra consideration for better-informed system management and remediation enhancement. Last but not least, the holistic study outcomes underscored the explicit value of applying complementary molecular approaches to achieve deeper insights into the functional status of a target NBS over time.
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.