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.
2010
Forfattere
Brita Toppe Maria HerreroSammendrag
I 2005 ble Phytophthora ramorum funnet på rododendron i parken på Gamlehaugen. I et felt med gamle, 2-3 meter høye planter med tykke stammer og greiner syntes sykdommen å ha forårsaket mest skade. Funnet ga oss anledning til å undersøke mærmere hvordan smitte av P. ramorum overlever i jord.
Forfattere
Lars Nesheim Uffe JørgensenSammendrag
In Denmark, Finland and Sweden cultivation of energy crops has been commercial for several years. In Norway there is hardly any commercial growing of agricultural crops for energy purposes. Cereal straw is to some extent used as a solid biofuel. The objective of this chapter is to give a review of the current production of different energy crops in the Nordic countries, and to present some ideas on what may be the future biofuels in these countries. The most important bioenergy crop concerning the area of cultivation is wheat for bioethanol on about 27 000 hectares in Sweden. That constitutes about 7 % of total area of wheat. There is now one factory for bioethanol production in Sweden, and two or three more plants are planned. In Finland reed canary grass is now grown on 20 000 hectares, and the energy crop may be used in about 12 power plants in bales or as fuel-mix. This crop is well suited for Finland and Northern Sweden, where the winters are cold. There is also commercial growing of reed canary grass for biofuel in Sweden, but the area is much lower than in Finland. The Ministry of Agriculture and Forestry in Finland has set a target to increase the area of energy crops to 100 000 hectares before 2016. In Sweden willow (Salix) is grown on about 13 500 hectares of agricultural land. The area is not increasing any longer, mostly due to reduced subsidies. In Denmark there is a considerable production of oil seed rape for biodiesel, but there are no adequate statistics on the oil use. In addition to the mentioned crops there is some commercial cultivation of other bioenergy crops, such as hemp, miscanthus and crops for biogas production. Phasing out fossil fuel use in the Nordic countries is a clear political focus even though the path to the goal is not yet defined in all countries. However, it seems clear that biomass will play a very significant role at least in the medium term within the next fifty years. This will be for heat and power, but also the demands for increased biofuel use in the transport sector will increase the need for biomass dramatically. First choice should be sustainable utilization of biomass residues. Growing dedicated energy crops is an option for delivering increased amounts of biomass.
Forfattere
Anne-Grete Roer HjelkremSammendrag
Abstract The thesis is about quantification of uncertainties in complex models. Models are built to describe, explain or predict a real world outcome. It is well known that models are related with uncertainty, and that uncertainties are related to how close the simulation is to the real world outcome. Still, uncertainties are rarely quantified in dynamic models. We have focused on parameter uncertainty and output uncertainty derived from the parameters. Uncertainty originated from the empirical data is integrated into the posterior parameter distributions through the likelihood functions. Additionally, uncertainty related to the representativeness of the collected data to the population has been focused. The Bayesian statistical framework, with the Markov chain Monte Carlo algorithm random walk Metropolis was used for model calibration in the four papers. The algorithm was found simple in idea and implementation into the computer program Matlab, but challenges emerged when the method was used at complex models. In this work these challenges have been pursued together with searching for efficiency improvements in order to make as few model evaluations as possible. Paper I: explores the challenges emerging when applying Bayesian calibration to a complex deterministic dynamic model of snow depth. How prior information and new data affect the calibration process, the parameter estimates and model outputs were demonstrated. Parameter uncertainty and model uncertainty derived from the parameters were quantified, visualized and assessed. The random walk Metropolis algorithm was used and in order to reach convergence more effectively, informative priors, Sivias" likelihood, reflection at the prior boundaries and updating the proposal distribution with parts of the data gave successful results. Methods for objective and correct determination of Markov chain convergence were studied, and the use of multiple chains and the Gelman-Rubin method was found useful. Paper II: presents a dynamic model for snow cover, soil frost and surface ice. The Bayesian approach was used for model calibration and sensitivity analysis identified the non-important parameters. Paper III: shows the importance of splitting the data several times in two for model development and assessment/selection, for the model to fit well to novel data from the system and not only to the specific data at hand. Different models of ascospore maturity of Venturia inaequalis were further developed and compared by the deviance information criterion and root mean square error of prediction to show model improvements, and the analysis of variance was used to show significance of the improvements. Paper IV: examines the potential effects of selection of likelihood function when calibration a model. Since the likelihood function is rarely known for certain, but gives a reasonable quantification of how probable the data are given model outcome, it is of great importance to quantify the effect of using different likelihood functions on parameter uncertainty and on model output uncertainty derived from the parameters.
Forfattere
Britt I.F. HenriksenSammendrag
Bakgrunnen for denne vurderinga er spørsmålstillinga i Høringsnotat fra Mattilsynet - Forslag til nye regler om økologisk produksjon og merking av økologiske produkter: "Bør kravet om at kalven skal kunne die fra mora minst tre dager etter fødselen videreføres, jf. §15 i forslaget til ny forskrift? Hvis ikke, bør det stilles andre krav til forhold rundt behandling av kalver og diing?" § 15. Fôring med melk til kalver Kalver skal kunne die i minst 3 dager etter fødselen. Ved kortere dieperiode enn 1 måned skal kalver kunne drikke av smokk frem til de er 1 måned gamle. Regelverksutvalget for økologisk produksjon ønskjer ei grundig vurdering av fordelar og ulemper knyta til §15 i samband med høringa. Vidare er det gjort ei vurdering av ulike påstandar ut frå litteratur og svar frå spørjeundersøking om diing som vart sendt vinteren 2009/2010 til alle økologiske mjølkeprodusentar. Spørjeundersøkinga var knyta til eit kunnskapsutviklingsprosjekt ved Bioforsk økologisk og Ku-kalv-prosjektet leia av Veterinærinstituttet, finansiert av MATFONDAVTALEN. Konklusjon: Det anbefalast å vidareføre kravet om diing. Anbefalinga er gjort ut frå vurderinga av fordelar og ulemper med regelen om tre dagars diing og at det pågår eit forskingsprosjekt finansiert av MATFONDAVTALEN som skal sjå på helseeffektar og dyrevelferd knyta til diing, og praktiske løysingar for å redusere stress ved fråskiljing ku-kalv. Ein bør vurdere krav om ekstra tilførsel av råmjølk rett etter fødsel i tillegg til diing, for å sikre at kalven får tatt opp nok av dei viktige immunstoffa som særleg er i den første råmjølka. Når ein etter kvart får resultat frå Ku-kalv-prosjektet bør ein vurdere om det er forskingsresultat som tilseier at regelen om tre dagars diing bør takast opp til vurdering igjen, og om ein bør sette krav knyta til fråskiljinga mellom ku og kalv.
Forfattere
Mekjell Meland Eva BirkenSammendrag
Det er ikke registrert sammendrag
Forfattere
Eva Birken Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Forfattere
Eva Birken Mekjell MelandSammendrag
Det er ikke registrert sammendrag
Forfattere
Eivind Vangdal Sigrid Flatland Iren Lunde KnutsenSammendrag
Resultat frå lagringsforsøk med 8 norske plommesortar i Ca og ULO-atmosfære vart presentert. Under begge desse vilkåra med 1-2% oksygen heldt plommene seg fastare og grønare enn i vanleg luft. Soppskadegjerarar vaks mindre aggresivt i luft med lite oksygen.
Forfattere
Eivind VangdalSammendrag
Gjennom optimal haustetid og betre mineralstatus (høgare kalsiumnivå; balansen mellom kalium+magnesium og kalsium) kan ein oppnå betre kvalitet. Både tiltak i konvensjonell og økologisk dyrking er omtala.
Forfattere
Eivind Vangdal Sigrid Flatland Ingvild MehlSammendrag
Experiments with foliar fertilization in plums have been performed in Western Norway. In one experiment possible effects of extra magnesium, potassium and the combination of both magnesium and potassium were compared to control trees given a standard foliar fertilization programme. In the other experiment the standard foliar fertilization programme was compared to control trees given soil fertilization only. Yield and fruit size as well as major fruit quality factors were registered. Leaves and fruit were analysed for major nutrients. No strong effects of foliar application with magnesium and potassium on fruit quality were observed. The treatments did not affect the content of major nutrients in leaves and fruit to such an extent that significant effects on fruit quality would be expected. The foliar fertilization programme tended to delayed maturation of the fruit as the fruit were greener and with less blush colour, firmer and had lower content of soluble solids and higher content of titratable acidity. The changes in separate quality factors were, however, not statistically significant. The foliar fertilized trees tended to have higher content of nitrogen in the leaves and lower content of the other major nutrients.