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.
2018
Sammendrag
The Norwegian per capita sales of wine have more than doubled over the past 20 years, while the sales of sprits and beer have declined. These changes are likely to be the effect of changes in economic, demographic, and attitudinal factors as well as the availability of wine. We estimated age-period-cohort (APC) logit models using data from a large repeated cross-sectional survey over the period 1991–2015. The estimation results indicate substantial effects of the APC variables as well as income, availability, and attitudes. The model was used to simulate wine consumption over the life cycle in different birth cohorts. The simulation results indicate that wine consumption frequency increases by age, and younger cohorts are expected to increase their consumption frequencies more than older cohorts, which suggests an increased wine consumption over time.
Forfattere
Eivind Vangdal Angela KoortSammendrag
The major sources of nutrients to organic grown apple trees are fertilizers made from manure, compost, bone meal, etc. Depending on humidity and temperature in soil and air, the nutrients are dissolved or mineralized and made available to the trees during the growing season. In conventional apple growing, the trees are given mineral fertilizers in early spring to improve the nitrogen status in the trees during flowering for better fruit set. Is it possible in an organic production system to increase the plant available nitrogen in the flowering period by application of liquid N-fertilizers? The standard fertilizer in Norwegian organic fruit growing is dried and pelleted chicken manure with bone meal and vinasse (Marihøne plus; NPK 8-4-5). In these experiments, a liquid fertilizer (Pioner Hi-fruit; NPK 4-1-5) based on vegetable matter plus potassium-vinasse was compared to the standard fertilizer. The liquid fertilizer was applied to the soil as fertigation from 2 weeks before the estimated start of flowering. The dry product was applied 2 weeks prior to flowering. To incorporate the fertilizers into the soil, a mechanical hoer (Orizzonti, Italy) was run in all plots after the application of dry fertilizer. The nitrogen and mineral contents in soil, leaves and fruit were analyzed. The liquid fertilization applied on the soil in the spring gave higher N-contents in soil and trees compared to the dried manure product. However, the increase in N-content was not very strong in the leaf samples. Apples from trees given high doses of liquid fertilizers were greener with less cover colour and higher IAD-indexes. Still they were softer and had less starch than fruit from other treatments.
Sammendrag
The population structure of cloudberry (Rubus chamaemorus L.), collected from Krkonose Mountains (the Czech Republic), continental Norway and Spitsbergen, was examinedusing microsatellite analyses (SSR). Among 184 individuals, 162 different genotypeswere identified. The overall unbiased gene diversity was high (̂h=0.463). A high level of genetic differentiation among populations (FST = 0.45; p < .01) indicated restricted gene flow between populations. Using a Bayesian approach, six clusters were found which represented the genetic structure of the studied cloudberry populations. The value of correlation index between genetic and geographical distances (r = .44) indicates that gene flow, even over a long distance, could exist. An exact test of population differentiation showed that Rubus chamaemorus populations from regions (Krkonose Mountains,continental Norway and Spitsbergen) are differentiated although some individuals within populations share common alleles even among regions. These results were confirmed by AMOVA, where the highest level of diversity was found within populations(70.8%). There was no difference between 87 pairs of populations (18.7%) mostly within cloudberry populations from continental Norway and from Spitsbergen. Based on obtained results, it is possible to conclude that Czech and Norwegian cloudberry popula-tions are undergoing differentiation, which preserves unique allele compositions most likely from original populations during the last glaciation period. This knowledge will be important for the creation and continuation of in situ and ex situ conservation of cloud-berry populations within these areas.
Forfattere
Anne-Grete Roer Hjelkrem Heidi Udnes Aamot Guro Brodal Einar Strand Torfinn Torp Simon G. Edwards Ruth Dill-Macky Ingerd Skow HofgaardSammendrag
High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2 + T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2 + T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2 + T2 in oat grains. Our data show that adequate predictions of the risk of HT2 + T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2 + T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2 + T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2 + T2 accumulation in oat grains. Our data indicated that HT2 + T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.
Forfattere
Anne Linn Hykkerud Eivind Uleberg Espen Hansen Marieke Vervoort Jørgen A.B. Mølmann Inger MartinussenSammendrag
Cloudberry (Rubus chamaemorus L.) is a wild perennial shrub growing on peatland with a circumpolar distribution. The combined berries have a high polyphenol content comprised primarily of ellagitannins. A few commercial cultivars are available, and pre-breeding trials on clonal material from different geographical origins are in progress. The objective of this study was to investigate how the content of polyphenols of four different cloudberry cultivars were affected by harvesting time and climatic variations during a 3-year-period. Plants were grown outside in plots and berries were harvested when mature. Berries were analyzed for total polyphenols and total anthocyanins by spectrophotometer. Total ellagic acid was identified and quantified using HPLC-MS after hydrolysis of the extracts. Results showed that all measured parameters; total anthocyanins, total polyphenols and ellagic acid are strongly influenced by the genetic background. Although low anthocyanin contents were present in all genotypes, they were highly affected by climatic conditions, being highest at low temperatures. However, the content of ellagic acid was less affected by environmental conditions and showed little response to changing temperatures. In conclusion, ellagitannin content was the most dominating polyphenol group observed in this study and was affected by genetics and is therefore a good breeding criterion for increased health benefit of cloudberry.
Forfattere
Markus Berger Stephanie Eisner Ruud van der Ent Martina Flörke Andreas Link Joseph Poligkeit Vanessa Bach Matthias FinkbeinerSammendrag
Due to the increasing relevance of analyzing water consumption along product life cycles, the water accounting and vulnerability evaluation model (WAVE) has been updated and methodologically enhanced. Recent data from the atmospheric moisture tracking model WAM2-layers is used to update the basin internal evaporation recycling (BIER) ratio, which denotes atmospheric moisture recycling within drainage basins. Potential local impacts resulting from water consumption are quantified by means of the water deprivation index (WDI). Based on the hydrological model WaterGAP3, WDI is updated and methodologically refined to express a basin’s vulnerability to freshwater deprivation resulting from the relative scarcity and absolute shortage of water. Compared to the predecessor version, BIER and WDI are provided on an increased spatial and temporal (monthly) resolution. Differences compared to annual averages are relevant in semiarid and arid basins characterized by a high seasonal variation of water consumption and availability. In order to support applicability in water footprinting and life cycle assessment, BIER and WDI are combined to an integrated WAVE+ factor, which is provided on different temporal and spatial resolutions. The applicability of the WAVE+ method is proven in a case study on sugar cane, and results are compared to those obtained by other impact assessment methods.
Forfattere
Stef Bokhorst Matty P. Berg Guro Kristine Edvinsen Jacintha Ellers Amber Heitman Laura Jaakola Hanne Mæhre Gareth K. Phoenix Hans Tømmervik Jarle W. BjerkeSammendrag
Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days at 6–7∘C) combined with episodic summer nitrogen (+N) depositions (5 kg N ha-1) on plant winter physiology, plant community composition and ecosystem CO2 fluxes of an Empetrum nigrum dominated heathland during 3 consecutive years in northern Norway. We expected that the +N would exacerbate any stress effects caused by the WW treatment. During WW events, ecosystem respiration doubled, leaf respiration declined (-58%), efficiency of Photosystem II (Fv/Fm) increased (between 26 and 88%), while cell membrane fatty acids showed strong compositional changes as a result of the warming and freezing. In particular, longer fatty acid chains increased as a result of WW events, and eicosadienoic acid (C20:2) was lower when plants were exposed to the combination of WW and +N. A larval outbreak of geometrid moths (Epirrita autumnata and Operophtera brumata) following the first WW led to a near-complete leaf defoliation of the dominant dwarf shrubs E. nigrum (-87%) and Vaccinium myrtillus (-81%) across all experimental plots. Leaf emergence timing, plant biomass or composition, NDVI and growing season ecosystem CO2 fluxes were unresponsive to the WW and +N treatments. The limited plant community response reflected the relative mild winter freezing temperatures (-6.6∘C to -11.8∘C) recorded after the WW events, and that the grazing pressure probably overshadowed any potential treatment effects. The grazing pressure and WW both induce damage to the evergreen shrubs and their combination should therefore be even stronger. In addition, +N could have exacerbated the impact of both extreme events, but the ecosystem responses did not support this. Therefore, our results indicate that these sub-arctic Empetrum-dominated ecosystems are highly resilient and that their responses may be limited to the event with the strongest impact.
Sammendrag
This paper presents an optimization model designed to find productivity functions for timber forwarding. Timber forwarding or skidding has for some 25 years been calculated using shortest path formulations on grid networks. Unfortunately, few productivity studies relate to such grids. Here, an inverse shortest path problem is presented, basically panning out costs on the grid based on point cost estimates. The formulation is tested using point cost estimates from the national forest inventories of Norway, together with a terrain model and other public spatial data (e.g. roads, water). The problem is optimized using the metaheuristic variable neighborhood search. The results of the test cases were achieved in reasonable time, and indicate that part of the solution space might be convex. The productivity function found for one of the test cases was used to create a variable forwarding cost map of the case area.
Forfattere
Di Zeng Michael R. Thomsen Rodolfo M. Jr. Nayga Heather L. RouseSammendrag
The association between the commercial food environment and childhood obesity is increasingly assessed in the literature, but little is known about the role of convenience stores, an important food retail format worldwide. This study helps bridge the gap using individual-level data containing measured body mass index (BMI) for public schoolchildren and geo-coded residence and store locations in Arkansas, United States. The distance from residence to the nearest highway is employed to instrument neighbourhood convenience store exposure, while controlling for possible confounding effects of other food stores. We find that exposure to at least one convenience store exposure is associated with a BMI z-score increase of 0.162 SD, and exposure to each additional convenience store is associated with a BMI increase of 0.071 SD. There is no evidence for a larger association among children from low-income families or those with limited access to healthy foods.
Sammendrag
Det er en rivende utviking i produksjon av spesial øl i Norge og etterspørselen etter norske råvarer - malt, humle og urter - er økende. Prosjektet har vist at en kan produsere malt med god kvalitet i Norge, men sortsgenskaper som er sentrale for malting vektlegges ikke spesielt i norsk byggfordling, og ingen norske byggsorter er per i dag godkjent som maltbygg. Ønsker en å dyrke godkjente maltbyggsorter, må en ta i bruk utenlandske sorter som Marthe og Quench. Dette er i stor grad relativt seine 2-radssorter som bare kan dyrkes i de beste korndyrkingsområdene på Østlandet og i Trøndelag. Skal en dyrke maltbygg i områder med begrenset veksttid, er en avhengig av å ta i bruk 6-radssorter som krever kortere veksttid fram til modning, for eksempel Arve og Varde. En del sentrale kvalitetsegenskaper er mindre gunstige hos 6-radssortene. Dette gjelder først og fremst egenskaper som påvirker maltutbyttet, liksom kornstørrelse og kornstørrelsesfordeling. Gamle sorter som er egnet for malting, liksom Varde og Domen, har dyrkingsmessige utfordringer knyttet til lange og svake strå som lett gir legde og kvalitesforringelse av kornet. Store forskjeller mellom år for avling og maltkvalitet for ellers like dyrkingsbetingelser, tyder på at en må regne med betydelge årsvariasjoner ved dyrking av maltkorn under norske værforhold...