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.
2020
Authors
Heidi KnutsenAbstract
«Norwegian Agriculture – Status and Trends 2019» provides a brief overview of major aspects of agriculture in Norway and summarises some of the information that is annually published within the sector.
Authors
Grete StokstadAbstract
No abstract has been registered
Authors
Ståle Størdal Minh Thi Hong Dinh Erik Haugom Gudbrand LienAbstract
We employ the event study methodology and simple descriptive measures to examine the performance of the Norwegian stock market before and in the first three months after the implementation of the lockdown policy in March 2020. Most of the financial losses occurred before the lockdown decision was made. In general, price volatility has been higher since the lockdown compared to the prior period. The information technology sector has performed best in the post-lockdown period, whereas the energy and finance sectors have performed worst. However, the finance sector has had a significant recovery in the post-event period. Among the marketplaces, Oslo Axess performed best in the month following the lockdown and has also experienced less volatility than Oslo Børs. A noticeable finding is that companies with headquarters in Norway have rebounded far better than those with headquarters abroad in the post-lockdown period.
Authors
Tore SkrøppaAbstract
No abstract has been registered
Authors
Sandra Rojas-Botero Jairo Solorza-Bejarano Johannes Kollmann Leonardo H. TeixeiraAbstract
Degraded tropical forests that were converted into pastures dominated by exotic grasses are a challenge for restoration due to arrested succession. Nucleation is a suitable strategy to restore such abandoned pastures as it can overcome seed and site limitation, and would foster the recovery of structural, functional, and species diversity. To explore the outcomes of different nucleation techniques in terms of richness, functional diversity, resource offer, and species and trait composition during the first year after implementation in an abandoned pasture in the tropical Andes, we conducted a field experiment with four nucleation treatments established in 1-m2 subplots, i.e. natural regeneration (control), seed rain transfer, seed bank transfer, and pre-grown plant mats. Number of species, functional diversity, proportion of natives, flowering and fruiting were response variables of the nucleation treatments and time since restoration using linear mixed-effects models. Species and trait composition trajectories over time were depicted with NMDS. Species richness and functional diversity of understory vegetation increased over time and with nucleation, being significantly higher by the final survey. Seed bank transfer introduced most species to the area in comparison to natural regeneration. Functional diversity, proportion of native, flowering, and fruiting species changed with time albeit with no differences among treatments. Species and trait composition showed convergence over time, which stresses the strong influence of environmental filtering in early restoration of abandoned pastures. Although positive aspects of planting trees and shrubs cannot be neglected, we argue that the incorporation of (several) more sophisticated nucleation techniques is beneficial for restoration of tropical forests.
Authors
Melesse Eshetu Moges Arve Heistad Thorsten HeidornAbstract
The blackwater stream of domestic wastewater contains energy and the majority of nutrients that can contribute to a circular economy. Hygienically safe and odor-free nutrient solution produced from anaerobically treated source-separated blackwater through an integrated post-treatment unit can be used as a source of liquid fertilizer. However, the high water content in the liquid fertilizer represents a storage or transportation challenge when utilized on agricultural areas, which are often situated far from the urban areas. Integration of microalgae into treated source-separated blackwater (BW) has been shown to effectively assimilate and recover phosphorus (P) and nitrogen (N) in the form of green biomass to be used as slow release biofertilizer and hence close the nutrient loop. With this objective, a lab-scale flat panel photobioreactor was used to cultivate Chlorella sorokiniana strain NIVA CHL 176 in a chemostat mode of operation. The growth of C. sorokiniana on treated source-separated blackwater as a substrate was monitored by measuring dry biomass concentration at a dilution rate of 1.38 d−1, temperature of 37 °C and pH of 7. The results indicate that the N and P recovery rates of C. sorokiniana were 99 mg N L−1d−1 and 8 mg P L−1d−1 for 10% treated BW and reached 213 mg N L−1d−1 and 35 mg P L−1d−1, respectively when using 20% treated BW as a substrate. The corresponding biomass yield on light, N and P on the 20% treated BW substrate were 0.37 g (mol photon)−1, 9.1 g g−1 and 54.1 g g−1, respectively, and up to 99% of N and P were removed from the blackwater.
Authors
Hella Ellen Ahrends Stefan Siebert Ehsan Eyshi Rezaei Sabine Julia Seidel Hubert Hüging Ewert Frank Thomas Döring Victor Rueda-Ayala Werner Eugster Thomas GaiserAbstract
Yield stability is important for food security and a sustainable crop production, especially under changing climatic conditions. It is well known that the variability of yields is linked to changes in meteorological conditions. However, little is known about the long-term effects of agronomic management strategies, such as the supply of important nutrients. We analysed the stability of four major European crops grown between 1955 and 2008 at a long-term fertilization experiment located in Germany. Six fertilizer treatments ranged from no fertilization over the omission of individual macronutrients to complete mineral fertilization with all major macronutrients (nitrogen, phosphorus, potassium and calcium). Yield stability was estimated for each crop x treatment combination using the relative yield deviation in each year from the corresponding (nonlinear) trend value (relative yield anomalies). Stability was lowest for potato, followed by sugar beet and winter wheat and highest for winter rye. Stability was highest when soils had received all nutrients with the standard deviation of relative yield anomalies being two to three times lower than for unfertilized plots. The omission of nitrogen and potassium was associated with a decrease in yield stability and a decrease in the number of simultaneous positive and negative yield anomalies among treatments. Especially in root crops nutrient supply strongly influenced both annual yield anomalies and changes in anomalies over time. During the second half of the observation period yield stability decreased for sugar beet and increased for winter wheat. Potato yields were more stable during the second period, but only under complete nutrient supply. The critical role of potassium supply for yield stability suggests potential links to changes in the water balance during the last decades. Results demonstrate the need to explicitly consider the response of crops to long-term nutrient supply for understanding and predicting changes in yield stability.
Abstract
Pythium species are ubiquitous organisms known to be pathogens to terrestrial plants and marine algae. While several Pythium species (hereafter, Pythium) are described as pathogens to marine red algae, little is known about the pathogenicity of Pythium on marine green algae. A strain of a Pythium was isolated from a taxonomically unresolved filamentous Ulva collected in an intertidal area of Oslo fjord. Its pathogenicity to a euryhaline Ulva intestinalis collected in the same area was subsequently tested under salinities of 0, 15, and 30 parts per thousand (ppt). The Pythium isolate readily infected U. intestinalis and decimated the filaments at 0 ppt. Mycelium survived on U. intestinalis filaments for at least 2 weeks at 15 and 30 ppt, but the infection did not progress. Sporulation was not observed in the infected algal filaments at any salinity. Conversely, Pythium sporulated on infected grass pieces at 0, 15, and 30 ppt. High salinity retarded sporulation, but did not prevent it. Our Pythium isolate produced filamentous non-inflated sporangia. The sexual stage was never observed and phylogenetic analysis using internal transcribed spacer suggest this isolate belongs to the clade B2. We conclude that the Pythium found in the Oslo fjord was a pathogen of U. intestinalis under low salinity.
Authors
Selamawit Araya Kidane Beira H. Meressa Solveig Haukeland Trine Hvoslef-Eide Christer Magnusson Marjolein Couvreur Wim Bert Danny L. CoyneAbstract
Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.
Authors
Svenja B. Kroeger Daniel T. Blumstein Kenneth B. Armitage Jane Margaret Reid Julien G.A. MartinAbstract
No abstract has been registered