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
Johannes DeelstraSammendrag
Climate change and Water Resources Management -International perspectives. The presentation gave an overview of data collection systems in use in Norway and their potentail benegfits for climate change studies.
Sammendrag
Forståelse av prosesser, strømningsveier for vann er viktig for å kunne foreta de riktige valg av tiltak mot landbruksforurensning. De dominerende strømnings veier for vann i landbruket ble presentert samt hvilken betydning de har for transport av næringsstofer og erosjon.
Sammendrag
It is well known that farming practices, soil type, topography and climatological conditions are important factors in nutrient loss generation from agricultural dominated catchment. Also catchment scale might play an important role in nutrient loss processes. Artificial drainage of agricultural land can lead to an increase in nutrient loss, however, its magnitude is very much influenced by the soil type and drainage system. An analysis has been carried out on measured runoff in catchment of varying size in Latvia, Estonia and Norway, the results of which were presented at the NHC
Sammendrag
A presentation of JOVA, the Agricultural Environmental Monitoring Programme in Norway which monitors and assesses nutrient - and soil loss from small agricultural dominated catchments. One of the major objectives is to document the effect of different agricultural production systems and site - specific characteristics on erosion and nutrient losses to surface waters and to advice local and central policymakers about agricultural production systems and their environmental effects. The programme has been in operation since 1992 in 9 catchments, varying in size from 1- 20 km2, representing different agricultural practices, climatological, topographical and geo-hydrological conditions. The core of the monitoring activities consists of discharge measurement and water sampling, providing data for nutrient load calculation
Sammendrag
Foredrag på "Conference on Modelling Hydrology, Climate and Land Surface Processes", Lillehammer, 14 - 16 September 2010, organisert av Norsk Hydrologiråd. Foredraget til JD et al hadde som tittel " Time resolution in discharge , hydrological response and catchment characteristics" og viste frram effekter av tidsoppløsning og nedbørsfeltstørrelse på hydrologiske karakteristikker.
Forfattere
Johannes DeelstraSammendrag
En presentasjon om matprodukson uner forhold med knappe vannressurser for Bioforsk ansatte. Som en del av "Faglig Forum" opplegget. Temaer som ble behandlet/presentert - hvor mye vann trenges for å dyrke fram matr, klær- hvor mye vann trenges det til vår daglige kosthold- matbehov og økning i verdensbefolkning- forskjellige vanningsmetoder- crossboundary river og knappe vannressurser, et eksemple fra Nilen- bevistgjøring viktig
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.