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.
2004
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Lars Sandved Dalen Øystein JohnsenSammendrag
Plant growth and adaptation to cold and freezing temperatures in a CO2-enriched atmosphere have received little attention despite the predicted effects of elevated CO2 on plant distribution and productivity. Norway spruce (Picea abies (L.) Karst.) seedlings from latitudinally distinct seed sources (66N and 60N) were grown for one simulated growth season under controlled conditions in an atmosphere enriched in CO2 (70Pa) and at ambient CO2 (40Pa), combined factorially with low (3.6mM) or high (15.7mM) concentrations of nitrogen fertilization.There was a clear difference between the two provenances in height growth, in the timing of bud set, and in freezing tolerance. Nitrogen fertilization increased height growth in both provenances, while CO2-enrichment stimulated height growth only in the southern provenance. We found no significant effects of elevated CO2 or nitrogen fertilization on the timing of bud set.During cold acclimation, freezing tolerance increased from -10C to -35C, and there was a marked increase in all soluble sugars except inositol. Elevated CO2 in combination with high nitrogen led to a slight increased freezing tolerance in both provenances during the early stages of cold acclimation. However, towards the end of cold acclimation, elevated CO2 and high nitrogen led to reduced freezing tolerance in the southern provenance, while elevated CO2 and low nitrogen reduced freezing tolerance in the northern provenance. These results suggest that CO2-enrichment influences the development of freezing tolerance, and that these responses differ with available nitrogen and between provenances.
Forfattere
Tor MuntheSammendrag
Cocksfoot mottle sobemovirus (CfMV) was first described from the UK by Serjeant in 1963. Later, it has been reported from several countries in North- and Central Europe, Canada, Japan and New Zealand. Cocksfoot seems to be its only natural host, in which it may cause dying out of plants and severe losses of yield. The severe effects of the virus have probably been a contributory cause of the decline in the area grown in UK.
Forfattere
V.M. Kosman A.N. Shikov V.G. Makarov B. Galambosi S. Dragland C. VenderSammendrag
Tre prøver av viltvoksende rosenrot fra Norge ble analysert i St. Petersburg, og resultatene er sammenlignet med tilsvarende prøver fra Italia, Finland og Russland. To av de norske prøvene viste seg å ha høg konsentrasjon av virkestoffer, og alle de norske var bedre enn prøvene fra Finland. Konsentrasjonen av rosavin og rosin var høgst i en prøve fra Altaifjellene i Russland, men de norske prøvene hevdet seg svært godt.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
This study was conducted to explore organic and conventional dairy farmers perceptions of risk and risk management, and to examine relationships between farm and farmer characteristics, risk perceptions, and strategies. The data originate from a survey of conventional (n = 363) and organic (n = 162) dairy farmers in Norway. Organic farmers had the least risk averse perceptions. Institutional and production risks were perceived as primary sources of risk, with farm support payments at the top. Compared to their conventional colleagues, organic farmers gave more weight to institutional factors related to their production systems. Conventional farmers were more concerned about costs of purchased inputs and animal welfare policy. Organic and conventional farmers management responses were more similar than their risk perceptions. Financial measures such as liquidity and costs of production, disease prevention, and insurance were perceived as important ways to handle risk. Even though perceptions were highly farmer-specific, a number of socio-economic variables were found to be related to risk and risk management. The primary role of institutional risks implies that policy makers should be cautious about changing policy capriciously and they should consider the scope for strategic policy initiatives that give farmers some greater confidence about the longer term. Further, researchers should pay more attention to institutional risks.
Forfattere
Geir ØstrengSammendrag
Artikkelen er basert på resultater fra et nordisk kurs i kalibrering av apparater for måling av CO2-frigivelse fra jord. Geir Østreng deltok på kurset med det apparatet som er brukt bl.a. i SIP Karbondynamikk i skogsjord 2000-2005, og han er medforfatter.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Ein gjer greie for mål og framgangsmåte, samt resultat frå innleiiande eksperiment i eit prosjekt som studerer korleis ein kan ta vare på og utnytte biologisk fiksert nitrogen i grønngjødslingsvekstar på ein best muleg måte.
Sammendrag
Conventional extreme value statistics and the calculation of return periods implicitly assume stationarity of distributions and statistical independence at least asymptotically (most extreme events).We demonstrate, using a collection of river runoff time series from Southern Germany, that these assumptions are invalid, and that temporal as well as spatial correlations prevail instead: temporal differences of distributions are nearly synchronized within a region, and there are systematic trends of percentiles especially at low flow conditions within the 20th century.As a consequence, the estimated return periods of a given threshold flow are fluctuating, in some cases even in a dramatic fashion. On the other hand, a general trend towards an increase in flood frequencies cannot be stated on basis of our investigations, in accordance with other recent findings (Mudelsee et al. 2003), but contrary to general expectations drawn from climate change studies.