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
Anne Kari BergjordSammendrag
Foredraget presenterte resultater fra forsøk der høsthveteplanter fra tre ulike steder med ulikt vinterklima ble testet for frosttoleranse regelmessig gjennom to vintre. Resultatene fra disse forsøkene ble brukt til å utvikle modellen FROSTOL som simulerer utvikling og endring av frosttoleranse fra såing av og gjennom vinteren. Modellens evne til å predikere grad av overvintring gjennom vintre med ulike værforhold ble testet ved bruk av et finsk datasett. Overvintringsskader kan forårsakes av mange ulike biotiske og abiotiske faktorer, men resultatene indikerte at FROSTOL fungerer relativt bra for vintre der frostskader er den avgjørende årsaken til utgang av planter. Den kan således være et viktig første skritt på veien mot en mer helhetlig overvintringsmodell for høsthvete.
Sammendrag
Timothy (Phleum pratense L) is the most important forage grass in Scandinavia and it is therefore highly interesting to study how it will perform in a changing climate. In order to model winter survival, the dynamics of hardening and dehardening must be simulated with satisfactory precision. We investigated an early timothy frost tolerance model (LT50 model), and an LT50 model for winter wheat. Based on the assumption that timothy has no vernalization requirement, unlike winter wheat, but does have the ability to adapt to cold temperatures in a process linked to stage of development, two alternative versions of the winter wheat model were also constructed. In total, these four candidate models were calibrated by a Bayesian approach for the timothy cultivar Engmo. The candidate models were validated using independent observations on LT50 in timothy at different locations reflecting differences in climate. A sensitivity analysis, using the Morris method, to identify important model parameters suggested that there is a connection between frost tolerance and stage of plant development, even if there is no vernalization requirement. The simplified winter wheat model was selected as the best candidate model for LT50 in timothy based on model selection criteria and its ability to capture the hardening and dehardening processes. The results from the Bayesian calibration suggest that there are no major regional differences in Norway calling for regional calibration. However, cultivar-specific calibration is probably required, since there are hardy and less hardy cultivars within the same species. A functional LT50 model would allow risk assessments to be made of future winter survival using specifically tailored and downscaled climate scenarios. (C) 2010 Elsevier B.V. All rights reserved.
Forfattere
Geir-Harald StrandSammendrag
The change from one landscape to another is gradual. Landscape classes can therefore be considered as theoretical concepts and a particular location or area can be affiliated with a number of different landscape classes. Landscape classification thus becomes a statistical and probabilistic exercise. Such a probabilistic approach to landscape regions can be made operational using a grid model combined with binary logistic regression. This approach was tested on a landscape region in Norway.
Forfattere
Lone Ross Gobakken Patricia K. LebowSammendrag
Mould growth on coated wood is today a genuine challenge for house owners. Environmentally sound wooden facades with long service lives and acceptable appearance are desired. The objective in this study was to investigate the accumulated mould growth on 13 different wood substrates with 3 surface coating systems by identifying the factors that contribute to the variation and to predict future performance. A generalized linear mixed model was fit to the data with the analysis showing that coating and exposure time both had highly significant influences on mould growth. Further, wood substrate was significant, but comparatively less than coating and exposure time. A smaller coefficient for mould coverage in the beginning of the exposure period gave the panels with one of the coating systems, BAP, a delay in mould growth, and the extrapolated values for years 6-12 indicate a longer aesthetic service life than panels with the two other coating systems. Coated heartwood as wood type was less susceptible to mould growth than coated mixed wood and coated sapwood. Acetylated pine as wood substrate and aspen as wood species had lower resistance to mould growth than the other wood substrates and wood species, respectively.
Forfattere
Anna GrzybekSammendrag
Det er ikke registrert sammendrag
Forfattere
Karen Refsgaard Thomas G. JohnsonSammendrag
Det er ikke registrert sammendrag
Sammendrag
Studying the winter survival of forage grasses under a changing climate requires models that can simulate the dynamics of soil conditions at low temperatures. We developed a simple model that simulates depth of snow cover, the lower frost boundary of the soil and the freezing of surface puddles. We calibrated the model against independent data from four locations in Norway, capturing climatic variation from south to north (Arctic) and from coastal to inland areas. We parameterized the model by means of Bayesian calibration, and identified the least important model parameters using the sensitivity analysis method of Morris. Verification of the model suggests that the results are reasonable. Because of the simple model structure, some overestimation occurs in snow and frost depth. Both the calibration and the sensitivity analysis suggested that the snow cover module could be simplified with respect to snowmelt and liquid water content. The soil frost module should be kept unchanged, whereas the surface ice module should be changed when more detailed topographical data become available, such as better estimates of the fraction of the land area where puddles may form.
Forfattere
H Annamali V Prasanna J Hafner Nagothu Udaya Sekhar Nils-Otto KitterødSammendrag
Det er ikke registrert sammendrag
Forfattere
Bruce Talbot Nils Egil Søvde H. Fridén Lars WilhelmssonSammendrag
This paper builds on findings from the recently finalised work package 3.9 of the EU Indisputable Key project. Three institutes cooperated in developing intricate models spanning from the standing tree to the dispatch yard of a Swedish window manufacturer. Numerous timber properties were assigned to RFID tags, applied to the log at felling by a specially adapted harvester head. Logs were allocated to each of seven sawmills according to their timber properties using an LP based optimisation procedure. Simulation was then used to compare the fate of traced timber throughout the production lines of one of the sawmills and its downstream manufacturers.....
Sammendrag
The aliphatic biopolyesters cutins and suberins have been suggested to significantly contribute to the stable pool of soil organic matter (SOM), and to be tracers for the above- or belowground origin of plant material. Contrary to other plant-derived aliphatic molecules found in the lipid fraction of soils, the stable isotope derived estimates of turnover of cutins and suberins have never been studied in soils. The aim of this study was to analyse the dynamics of shoot- and root-derived biomarkers in soils using a wheat and maize (C3/C4) chronosequence, where changes in the natural 13C abundance can be used to evaluate the incorporation of new carbon into SOM at the molecular level. The relative distribution of aliphatic monomers in wheat and maize roots and shoots suggested that a,u-alkanedioic acids can be considered as root-specific markers and mid-chain hydroxy acids as shoot-specific markers. The contrasting distribution of the plant-specific monomers in plants and soils might be explained by different chemical mechanisms leading to selective degradation or stabilization of some biomarkers. The changes of the 13C isotopic signatures of these markers with years of maize cropping after wheat evidenced their contrasted behaviour in soil. After 12 years of maize cropping, shoot markers present in soil samples probably originated from old C3 vegetation suggesting that new maize cutin added to soils was mostly degraded within a year. The reasons for long-term stabilization of shoot biomarkers remain unclear. By contrast, maize root markers were highly incorporated into SOM during the first six years of maize crop, which suggested a selective preservation of root biomass when compared to shoots, possibly due to physical protection.