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.
2007
Forfattere
Elena A. Kasatkina Oleg I. Shumilov Paul E. Aspholm Natalia V. LukinaSammendrag
Among some of the mysteries of the Tunguska meteorite event, is the cause of the accelerated tree growth after 1908 in the catastrophe area (about 2000-2500 km^2). The main explanation of accelerated growth of old trees, was a result of decrease of competition level due to falling of considerable part of neighbour trees. We analyzed all available tree ring records (more than 100) including our own ones collected in the Taymir Region of Northern Siberia (72N; 105E) at a distance of about 1500 km to the North from the Tunguska catastrophe epicentre (61N; 102E). It was found that there were a considerable increase of tree ring growth in 1908 over a vast area of Siberia (60N-75N; 80E-110E) that at much more vast area (10^3 times more) than had been earlier considered. The similar effect was detected after the Chulym bolide explosion in 1984 (57.7N; 85.1E). Of course, the Chulym forest response area was some smaller taking into account incomparable powers of Tunguska and Chulym events). It is obvious that the interpretation mentioned above, of tree growth observed too far from epicentre, could hardly be accepted. A more likely hypothesis is that the growth of the trees became stimulated by the matter from comet that where spread over a large territory of Eurasia. It is generally believed that meteorites and comets delivered large amounts of simple organic composites to the early Earth. Another hypothesis is connected to NO produced during the event analyzed. For example, in time the Tunguska event the comet (probably fragment of the comet Enke) tail started to influence the Earth atmosphere several days before the fall of the meteorite causing optical anomalies observed mainly westwards from the place of TO explosion (Western Siberia, European Russia, Northern Europe). We discuss as well the role of "small signals" in simulation of biological object response. The work was supported by a grant from the Russian Foundation for Basic Research (grant N 05-04-97528), by the Program "Biodiversity and dynamics of gene pool" of the Russian Academy and by the Regional Scientific Program of the Murmansk region.
Forfattere
Leiv Mortensen Hans Martin HanslinSammendrag
I 2004 startet et relativt omfattende klimaforskningsprogram i Bioforsk med en total ramme på ca. 20 millioner kroner over 5 år. I løpet av de tre årene som har gått, er det blit gjennomført en lang rekke forsøk for å belyse hva som kan skje ved en framtidig klimaendring, blant annet med høsthvete.
Forfattere
Marie Alexis Daniel Rasse C. Rumpel G. Bardoux N. Péchot P. Schmalzer B.G. Drake A. MariottiSammendrag
Fire profoundly modifies the terrestrial C cycle of about 40% of the Earth"s land surface. The immediate effect of fire is that of a net loss of C as CO2 gas and soot particles to the atmosphere. Nevertheless, a proportion of the ecosystem biomass is converted into charcoal, which contains highly recalcitrant molecular structures that contribute to long-term C storage. The present study aimed to assess simultaneously losses to the atmosphere and charcoal production rates of C and N compounds as a result of prescription fire in a Florida scrub-oak ecosystem. Pre-fire and post-fire charred and unburned organic matter stocks were determined for vegetation leaves and stems, litter and soil in 20 sub-plots installed in a 30-ha area that was subjected to prescribed fire. Concentrations of C and N were determined, and fluxes among pools and to the atmosphere were derived from these measurements. Soil C and N stocks were unchanged by the fire. Post-fire standing dead biomass contained 30% and 12% of pre-fire vegetation C and N stocks, respectively. In litter, post-fire stocks contained 64% and 83% of pre-fire C and N stocks, respectively. Most of the difference in relative losses between vegetation and litter could be attributed to substantial litter fall of charred and unburned leaves during the fire event. Indeed, an estimated 21% of pre-fire vegetation leaf C was found in the post-fire litter, while the remaining 79% was lost to the atmosphere. About 3/4 of the fire-induced leaf litter fall was in the form of unburned tissue and the remainder was charcoal, which amounted to 5% of pre-fire leaf C stocks. Charcoal production ranged between 4% and 6% of the fireaffected biomass, i.e. the sum of charcoal production and atmospheric losses. This value is below the range of literature values for the transformation of plant tissue into stable soil organic matter through humification processes, which suggests that fire generates a smaller quantity of stable organic C than humification processes over decades and potentially centuries.
Forfattere
Bjørn Molteberg Frank EngerSammendrag
Dette er en forvaltningsoppgave som gjennomføres på oppdrag fra Mattilsynet (tidligere Landbrukstilsynet) ( www.mattilsynet.no ). Målet er å framskaffe resultater for godkjenning av nye sorter for opptak på norsk sortsliste. ( http://www.mattilsynet.no/planter/sortsgodkjenning/offisiell_registrering_av_plantesorter_10655 ) Prøvingen er en kontinuerlig, ikke tidsavgrenset prøving. Flerårige arter legges ut to ganger med tre registrerings- og høsteår etter hvert utlegg. Ettårige arter prøves i tre år. Artene blir som hovedregel prøvd i fem distrikter, Østlandet, Fjellbygdene, Vestlandet, Midt-Norge og Nord-Norge. I 2006 var det sorter av følgende arter med i prøvingen: Timotei, engsvingel/raisvingel/strandsvingel, engelsk (flerårig) raigras, strandrør, engrapp, rød- og hvitkløver og westervoldsk- og italiensk raigras. Totalt var det 50 sorter i prøving, ingen av disse var ferdig prøvd. I tillegg var det med 39 målesorter. Sorter som var ferdig prøvd i 2006 (24 stk.) kommer i tillegg til de nevnte 50. Disse er presentert i egen rapport. (Bioforsk Fokus Vol. 2 Nr. 5 - 2007).
Forfattere
Bjørn Molteberg Frank EngerSammendrag
Dette er en forvaltningsoppgave som gjennomføres på oppdrag fra Mattilsynet (tidligere Landbrukstilsynet) ( www.mattilsynet.no ). Målet er å framskaffe resultater for godkjenning av nye sorter for opptak på norsk sortsliste. ( http://www.mattilsynet.no/planter/sortsgodkjenning/offisiell_registrering_av_plantesorter_10655 ) Prøvingen er en kontinuerlig, ikke tidsavgrenset prøving. Flerårige arter legges ut to ganger med tre registrerings- og høsteår etter hvert utlegg. Ettårige arter prøves i tre år. Artene blir som hovedregel prøvd i fem distrikter, Østlandet, Fjellbygdene, Vestlandet, Midt-Norge og Nord-Norge. I 2006 var det sorter innen artene timotei, engsvingel, engelsk (flerårig) raigras, engrapp, rød- og hvitkløver og westervoldsk raigras som var ferdig testet. I alt 24 sorter var ferdig testet og av disse er 10 anbefalt godkjent, (2 engsvingel, 4 engelsk (flerårig raigras), 2 engrapp, 1 hvitkløver og 1 westervoldsk raigras.
Forfattere
Trygve S. Aamlid Nicholas JarvisSammendrag
Soil water repellency (hydrophobicity) is a common problem on sand-based golf greens. Due to this phenomenon, soil water may percolate as "finger flow" rather than uniformly through the soil profile. The objective of this project was to investigate the effect of a commonly used wetting agent, Primer 604, on turf quality and leaching of two fungicides from two contrasting rootzones. The preliminary conclusions are as follows: 1. The wetting agent (WA) improved turf quality of straight sand rootzones during the warm and dry summer. Rootzone containing compost were not affected by WA. 2. WA lead to more water retention in the thatch layer and thus a tendency to more fungi during the rainy fall season. Again, the effect was mostly expressed on straight sand rootzones. 3. Water droplet intiltration tests showed that straight sand rootzones were strongly hydrophobic, even at 3-5 cm depth, i.e. under the thatch layer. Compost-amended rootzones were less hydrophobic, and only in the thatch layer. 4. WA reduced the spatial variation in soil water content, notably in the 4-15 cm layer on straight sand plots. This suggest that water percolation was more uniform after use of WA. 5. Fungicide leaching did not occur from Green Mix rootzones, even for azoxystobin + propicionazole used at high "American" rates. 6. Use of WA significantly reduced leaching of the fungicides iprodione, azoxystrobin and propiconazole from straight sand rootzones.
Forfattere
Trygve S. Aamlid Peter LandschootSammendrag
Spent mushroom substrate (SMS) is used by the turf industry in the northeastern United States for soil improvement. When tilled into soil at high rates, some turfgrass managers claim that SMS inhibits turf seed germination. Our objectives were 1) to determine if fresh SMS inhibits turf seed germination and, if so, which species are most adversely affected; 2) to evaluate whether any inhibition caused by SMS is due to osmotic effects or toxicity of compounds in SMS extracts; 3) to determine if any negative effect of SMS on germination can be eliminated by leaching the SMS-amended soil before seeding; and 4) to assess the performance of SMS on seedling emergence in the field. Germination of nine turfgrass species was evaluated in mixtures made from fresh SMS [electrical conductivity of saturated paste extract (ECe) = 11.9 dS m-1] and a loamy sand soil. Germination inhibition due to SMS was most pronounced in the following order: Colonial bentgrass (Agrostis capillaris L.) > sheep fescue (Festuca ovina L. ssp. hirtula [Hackel ex Travis] Wilkinson) > Kentucky bluegrass (Poa pratensis L.) > hard fescue (Festuca trachyphylla [Hackel] Krajina]) > creeping bentgrass (Agrostis stolonifera L.) > Chewings fescue (Festuca rubra L. sp. commutata [Thuill.] Nyman) = strong creeping red fescue (Festuca rubra L. ssp. rubra Gaud.) > slender creeping red fescue (Festuca rubra L. sp. litoralis [Meyer] Auquier) > perennial ryegrass (Lolium perenne L.). SMS had a stronger negative effect on germination rates (GRs) than on final germination percentages (FGPs). Germination of perennial ryegrass and Kentucky bluegrass on blotter paper moisted with SMS-extracts or polyethylene glycol of equivalent osmotic potentials showed that the inhibition was primarily due to osmotic effects. In an experiment with a 50% soil / 50% SMS (v/v) mixture, Kentucky bluegrass germinated better in pots that had been watered with 133 or 167% of the evaporation rate for ten days prior to seeding than in unleached pots. Although the negative effect of SMS on seed germination was not confirmed in a field study where ECe values never exceeded 4.1 dS m-1, we conclude that incorporation of high rates of SMS represents a potential problem for turfgrass establishment.
Sammendrag
Soppen ble første gang påvist i Norge i 1999 og siden er den funnet hos mange jordbærprodusenter.
Forfattere
Arild Sletten Leif SundheimSammendrag
Pærebrann er en alvorlig sjukdom på eple, pære og prydplanter i rosefamilien. De siste femti år har sjukdommen vært under spredning i Europa. Bakterien som forårsaker pærebrann er en fremmed art under spredning i Norge.
Forfattere
Trond HofsvangSammendrag
Søramerikansk minerflue er siden 1995 funnet flere ganger i norske veksthus. Arten har hittil ikke etablert seg i Norge, da alle fluer funnet i veksthus er utrydded.