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.
2005
Forfattere
Jorunn BørveSammendrag
Angrep av bitterrote på eple etter ei tid på kjølelager er ikkje uvanleg og synest kanskje å vera meir vanleg no enn det var før. Dette kan skuldast endringar i fungicidbruk eller at sortane me dyrkar no er meir mottakelege for denne sjukdomen. Biologien til sjukdomen er ikkje undersøkt under norske tilhøve, men denne artikkelen gjev eit kort oversyn over kunnskap frå andre land. Bitterròtesoppen likar varme og fuktige tilhøve ved infisering og smitten vert spreidd med vassdropar. Hovudsmittekjeldene i andre land er kreftsår og mumifiserte eple. Tilrådde tiltak er fjerning av smittekjelder og sprøyting med fungicid heile sesongen. Sidan bitterròte-soppen er varmekjær vil slike sprøytingar i Noreg vera mest aktuelle frå bløming og fram mot hausting.
Forfattere
Espen Govasmark Arvid Steen Anne Kjersti Bakken Turid Strøm Sissel Hansen Aksel Bernhoft Espen GovasmarkSammendrag
På norske økologiske husdyrgardar var innhaldet av og balansen mellom koppar, molybden og kobolt i grovfôret ikkje god nok til å møte dyra sine behov. Mineralblandingar eller kraftfor tilsett koppar og kobolt må brukast til dyra for å sikre dei ei god forsyning.
Forfattere
Espen Govasmark Arvid Steen Anne Kjersti Bakken Turid Strøm Sissel Hansen Espen GovasmarkSammendrag
Innhaldet av sink, jern og mangan i hausta grovfôravling på norske økologiske husdyrbruk vart halde saman med normene for forsyning av desse minerala til drøvtyggarar. Ut frå normene var kan hende forsyninga av sink for dårleg.
Sammendrag
Blomster er både dekorative og viktig i hverdagslivet vårt. Euphorbia pulcherrima Willd. Ex Klotzsch, julestjerne (poinsettia på engelsk) er en av de blomstene som har stor symbolverdi og som dyrkes i mange land i verden (Ecke III et al. 2004). Julestjernen har blitt vår mest populære juleblomst. Det produseres faktisk mellom 5 og 6 millioner julestjerner årlig i Norge (Hagen 2004). Julestjernen framviser store variasjoner i forskjellige deler av verden, fra å være høye og busklignende til kompakte potteblomster med mange grener. Mange patogener og skadegjørere kan angripe julestjerne, blant annet virus. Poinsettia mosaic virus (PnMV) og poinsettia latent virus (PnLV) er to virus som ofte infiserer julestjerne. PnMV forårsaker symptomer på bladene slik at kvaliteten blir redusert i følsomme sorter. Vi ønsker å lage PnMV-resistent julestjerne for å kunne få til en julestjerne av ennå høyere kvalitet. I tillegg ønsker vi å bruke samspillet mellom PnMV og julestjerneplanta som et modellsystem for å bygge opp kompetansen på genmodifisering av planter.
Sammendrag
Et forsøk med plensorten Nor i Telemark i 2003/04 viste følgende: (1) Ved frøavl av engkvein fører kutting av frøhalmen til 10-15% reduksjon i neste års frøavling sammenliknet med tradisjonell halmfjerning. (2) Etter fjerning av engkveinfrøhalmen er det ingen grunn til å avpusse stubben, selv om denne er 15-20 cm lang. · (3) (3) Brenning av engkveinfrøeng kan ikke anbefales, verken høst eller vår. Vårbrenning kan riktignok redusere forekomsten av markrapp, men gir samtidig mindre frøavling av engkvein.
Sammendrag
Kombinasjonen av Stratego og Stereo i hel og halv dose og til forskjellige sprøytetider er prøvd ut. De høyeste avlingene ble oppnådd ved to gangers behandling, men det var én behandling ved BBCH 45 som gav det beste økonomiske utbyttet både i 2004 og i sammendrag over to år og Stratego var et hakk bedre enn Stereo. Brutto avlingsresultat var litt bedre ved å bruke en hel dose, men en halv dose gav likevel et bedre økonomisk utbytte. En hel dose Stereo alene ved BBCH 32 gav negativt utbytte for sprøyting.
Forfattere
Helge Bonesmo Anne Kjersti BakkenSammendrag
Morphology and phenology, including stolon disintegration, of white clover were studied at two sites during three years after sowing. The plants reached their maximum size in late summer in the first year after sowing, and the populations contained at that time mainly taprooted plants. The later fragmented plants were smaller in most of the investigated characteristics. A function for daily transition rate from taprooted to fragmented plants related to daily mean temperature is presented. Deviations between the recorded and the calculated proportion taprooted plants were small; the overall root mean square error was 5.7 % units. Our data indicated that there is a low temperature requirement that must be met prior to onset of transition. We also suggest that in further modelling of white clover temperature responses, the effect of day length should be accounted for, especially if the data are collected from sites with a considerable latitudinal spread.
Forfattere
Christian E. MongSammendrag
The strategy for genetic conservation in Norway aims to manage existing adaptions and thus secure each species\" ability to adapt to environmental change and to evolve. The main aims of this report are three-fold:register the regeneration of lime/linden Tilia cordata Miller in three regions of Southern Norwayidentify factors influencing regenerationsuggest means to secure a sustainable management of this species. A total of 27 sites were studied in the eastern, southern, and western regions of South-Norway. Environmental variables were sampled from 217 genets of lime. The topography was categorised, shoots (shorter than 137 cm above grond) counted, and the diameters of all stems (taller than 137 cm) measured. A search was made for seedlings at every site.Of the adult limes, 53% were rooted in ground sloping more than 30 in topography classified as scree or precipice. There was a positive assosiation between clonal regeneration, expressed as number of stems per genet, and steep terrain. The populations of lime in Southern Norway may thus be the survivors after more extensive forests 5-6000 years before present.By looking at frequencies of stems per diameter class, after an approach by Leak (1965), one may evaluate population dynamics based on data collected from one season only. According to this approach the populations for all three regions are evaluated as stable or growing in the sense that the density of stems per genet may be increasing.Only 11 seedlings of lime were found. These were all found in the climatically warmest parts of the country, in southern Vest Agder and inner parts of Oslofjorden. Most of them had established in dense vegetation on relatively level ground. Hence, different factors may govern sexual and clonal regeneration - and steep terrain does not seem to be a part of the regeneration niche of seedlings.A series of studies from Great Britain demonstrate that lack of sexual regeneration in lime is attributable to low temperatures. Fruits collected in northern England and Scotland are unfertilise because the pollen tube does not grow into the stigma in the prevailing climate of that region.Many parts of South-Norway have comparable temperatures during the flowering season of lime. Based on fruit collections from three years in Sogn og Fjordane, in 1994, 1995, and 2004, there is evidence that at least some years fertilisation takes place and some embryos develop. Still, temperature is the most plausible factor that may limit the sexual regeneration of lime in South-Norway - many of the embryos have not ripened properly, indicating a too short growing season.The importance of this factor should be further studied by germination experiments. In addition to germination tests, mapping of genetic variation both at the within and at the between stand level of lime is recommended to ensure a sustainable management can be given to lime in Norway.
Forfattere
Marcel van Oijen Mats Høglind Hans Martin Hanslin Nick CaldwellSammendrag
Previously, the literature on the growth of timothy (Phleum pratense L.) in Scandinavia was reviewed and a simple process-based model was developed to explain and predict the response of this species to different environments and management regimes. The model could not be tested in detail, because only biomass data were available at the time. However, recent experimental work has generated a large (n = 633) and uniquely detailed dataset on the growth and underlying physiology of timothy and its response to cutting at different growth stages. The present study aimed to use this dataset to test the model, and to use the model to identify the key physiological and morphological mechanisms that determine the regrowth rate of timothy after cutting. Model testing consisted of comparing simulations and measurements for eight variables: biomass, leaf area index (LAI), tiller and leaf density, rates of leaf appearance and elongation, carbohydrate concentration, and specific leaf area. Although the new data referred to a different cultivar, a different site, and different years from those used in the original model parameterization, the model was still able to account for nearly half the variation in the dataset [r2 = 0.468, normalized root mean squared error (RMSE) = 0.631]. This suggested that the key assumptions of the model (i.e., dependence of growth and allocation on the source-sink balance of the plants and a dose link between tillering and leaf area dynamics were plausible. However, the original model was not able to account for the observation that cutting at early heading tended to be followed by a longer lag phase than cutting at anthesis. We identified six mechanisms, not previously incorporated in the model, that improved its behavior: (1, 2) dependence of tillering and leaf appearance rate on carbohydrate concentration, (3, 4) dependence of leaf appearance and leaf elongation rate on plant phenological stage, (5) sprouting of new tillers from decapitated generative tillers, and (6) proportionality of the number of elongating leaves with tiller size. Incorporation of these mechanisms, followed by reparameterization using a Metropolis-Hastings Monte Carlo method, improved performance statistics (r2 = 0.521, normalized RMSE = 0.415) and explained the long duratjon of slow growth after early cutting. These mechanisms may thus be keys to understanding timothy regrowth.
Sammendrag
Plant production in northern countries is hampered by a short growing season. In Norway, waterpower provides relatively cheap and renewable energy that can be used for artificial lighting. Light is often the limiting factor for plant growth and productivity in greenhouses, and the use of artificial radiation became already early last century an important subject for investigation in Norway. Development of different lamp types gave rise to investigations of light quality on plant performance. Artificial irradiation was primarily confined to plant propagation. Large-scale irradiation of entire crops started in Norway in 1989 and has given rise to a marked increase in winter production of flowers and vegetables. The Norwegian Crop Research Institute performs applied research in all chains of plant production. Research on greenhouse production is coordinated from Særheim Research Centre. Særheim is located in the southwest of Norway where 80% of tomatoes and 50% of the Norwegian cucumbers are produced. Research on the use of artificial light for cucumber production started here in 1990. After that, production systems for lettuce, herbs, strawberry, tomato and sweet pepper were developed. Growers that nowadays use our system for year-round production of cucumbers have increased their yield from 40 to 160 kg/m2. In 2004, we were the first to reach an annual yield of 100 kg/m2 in tomato. In our applied research, consumer and wholesaler demands define the quality aspects of food to be produced. Consumers increasingly demand save and healthy food of high quality. At Særheim Research Centre, effects of environmental conditions (light, temperature, CO2, air humidity, nutrients, growth media) and cultural practices (training, irrigation, harvesting) on size, colour, shelf life, taste and biochemical compounds are being quantified. It could be shown how light intensity and light quality effects the contents of chlorophyll, anthocyanins, ascorbic acid and nitrate in lettuce, shelf life and taste in herbs, taste and antioxidant activity in strawberry, titratable acidity and the contents of phenolics, ascorbic acid, lycopene and soluble solids in tomato. Results will be presented at the workshop. The favourable ratio between light and temperature in our region offers an opportunity to produce high quality products year-round. Norway is known as a healthy country, with little problems with pests and diseases, with an availability of renewable energy, organic growth media and organic fertiliser and with a high water quality. This gives rise to a development of organic production. Research on organic production of greenhouse vegetables started at Særheim in 2003. By now, a rational growing system for organic production of tomato is developed and a system for cucumber production is on trial. Preliminary trials show differences in the content of phenolic compounds, ascorbic acids and antioxidant activity in fruits and plants grown on organic growth media when compared to rockwool. Results will be presented at the workshop.