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.
2011
Forfattere
Kjell Andreassen Volkmar Timmermann Nicholas Clarke Ingvald Røsberg Halvor Solheim Wenche AasSammendrag
Helsetilstanden hos bartrær må betegnes som tilfredsstillende, men hos gran ble det observert en del toppskranting og avdøing i hogstklasse 3 og 4. Vi registrerte få insekt- og soppskader på gran der 0,4 % av trærne var skadet, mens 1,7 % av furutrærne hadde slike biotiske skader. Antall nye toppbrekk, vindfall og andre snø- og vindrelaterte skader hos bartrærne var omtrent på samme nivå som tidligere i overvåkingsperioden (hhv. 1,2 og 1,4 % for gran og furu). Av treslagene gran, furu og bjørk er det fortsatt bjørk som er mest utsatt, der 9,4 % av bjørketrærne var angrepet og skadet av insekter, hovedsakelig av fjellbjørkemåleren, mens 9,2 % av bjørketrærne var angrepet av bjørkerustsopp og 3 % hadde skader med abiotiske årsaker.....
Forfattere
Guro HenselSammendrag
På oppdrag for Vestby kommune har Bioforsk Jord og miljø foretatt prøvetaking av bekk og drensvann nedenfor det nedlagte deponiet på åmodt ved Hølen i Vestby. Deponiet var i drift fra 1957- 1978, og det ble deponert husholdningsavfall, industriavfall og slam. Deponiet er godt overdekket med leir-holdige jordmasser og tidligere vurderinger tilsier ingen konflikt mellom deponiet og dagens arealbruk. Det er god avskjæring av overvann, og liten innstrømning av grunnvann til deponiet. Sigevann fra deponiet slippes ut i åmodtbekken sammen med vann fra nedbørfeltet oppstrøms deponiet. Tidligere undersøkelser har ikke påvist utslipp av gass fra deponioverflaten. Etter krav fra Fylkesmannen høsten 2006, er det satt opp et overvåkningsprogram for å følge opp sige-vannspåvirket vann, samt resipienten som er åmodtbekken. Bioforsk Jord og miljø har vært ansvarlig for prøvetaking og oppfølging av deponiet i 2010.
Forfattere
Ingeborg KlingenSammendrag
Det er ikke registrert sammendrag
Sammendrag
The two spotted spider mite Tetranychus urticae is known to overwinter as hibernating females, and these partly inactive females may harbour Neozygites floridana. N. floridana is a fungal natural enemy of spider mites. The aim of this study was therefore to investigate whether N. floridana may be present inside living hibernating females of T. urticae throughout the winter season, and if so, in what prevalence and what stage of its fungal life cycle. Hibernating T. urticae females were investigated for the presence of fungal structures throughout one winter (October 12, 2006 to February 19, 2007) in field-grown strawberries in a cold climate in Norway (min. ambient temp -15.3oC). The study confirmed that N. floridana survived the winter as a semilatent hyphal body infection, protected inside live hibernating females. The beneficial fungus N. floridana is therefore ready to develop and sporulate as soon as climatic conditions permits, resulting in early season infection of T. urticae. An early-season infection of N. floridana that may result in the control of T. urticae in strawberries is important, since T. urticae is known to cause reductions in strawberry yield at much lower population levels in early season than in late season. For N. floridana to control T. urticae populations early in the spring, factors important for sporulation and dissemination of the fungus needs to be favoured. The adapted use of pesticides, especially fungicides might therefore be very important at this time of the year.
Sammendrag
The strawberry blossom weevil (Anthonomus rubi) is a small univoltine weevil severing the flower buds of strawberry and some other species of Rosaceae in order to provide for its offspring. The damage made by the weevil in Norwegian strawberry fields is increasing as chemical control is proving difficult and large numbers of weevils are observed in yet more districts. To develop new strategies to control the weevil, a better understanding of its biology is needed. Most studies of A. rubi have focused on the period when bud damage is done, whilst less is known about the ecology and behaviour at other times of the year. The literature on overwintering habits indicates that in the UK A. rubi leaves the strawberry field to overwinter, while elsewhere in Europe they may stay in the field. In a Norwegian project we used emergence traps and laboratory inspection of individual plants to search for weevils in the late autumn and early spring. In fields with weevil problems, we found significant numbers of A. rubi, typically 1-5 per plant (average of 10 plants) shortly before snow fall, and similar numbers early in the spring. The overall sex ratio was close to 1:1. We also found large numbers of overwintering weevils in plants that had been terminated with glyphosate, indicating that weevils were not repelled by dying plants as overwintering habitat. This considerable presence of weevils in the crop throughout the year could increase the chance of succeeding with alternative methods like microbiological control or mass trapping. It also implies that terminated (glyphosate-treated etc) fields should be ploughed on cool days in the autumn (A. rubi cannot fly at low temperatures) to bury the weevils, and not be left alone till late in the spring for weevils to escape.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Yehia Sayed El-temsah Alena Sevcu Erik Joner Miroslav CernikSammendrag
Nanoscale zero-valent iron particles (nZVI), with sizes smaller than 100 nm, are promising for environmental remediation of polluted water, soil and sediments. nZVI particles have high potential for migration in the environment and are likely to interact not only with pollutant chemicals but also with living organisms. For these reasons, an environmental concern is rising with respect to unintended effects that need to be weighed against the benefits of remediation. The nZVI particles have a tendency to release electrons and Fe2+. The Fe2+ can convert less reactive hydrogen peroxide to more reactive oxygen species, particularly hydroxyl radicals, via the Fenton reaction. Hydroxyl radicals show strong biochemical activity and can react directly with membrane lipids, proteins and DNA. Reactive oxygen species are normally scavenged by antioxidants and various enzymes; however, elevated concentrations of ROS in microbial cells can result in oxidative stress. Cells under severe oxidative stress show various dysfunctions of membrane lipids, proteins and DNA. This review focuses on the processes resulting in oxidative stress and on up-to-date studies of nZVI-induced intracellular changes leading to such stress in microorganisms.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Grete Helen Meisfjord Jørgensen Knut Egil BøeSammendrag
Det er ikke registrert sammendrag
Forfattere
grete h m jørgensenSammendrag
Paddock size and enrichment - the effects on horse behavior Grete H.M. Jørgensen1 and Knut E. Bøe2 1Bioforsk Norwegian Institute for Agricultural and Environmental Research, 8860 Tjøtta 2Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, UMB, 1430 ås Corresponding author: +47 40 76 67 69 e-mail grete.jorgensen@bioforsk.no New regulations for horse keeping in 2005 suggested a paddock size of at least 300 m2 per horse and that every horse should have at least 2 hours turnout per day. Some of this time could however be replaced with forced exercise if the horse was kept in a box and not in a tie-stall. Whether this paddock size is large enough and how exercise affects horse behavior and activity during turnout has not been studied in detail. Horses are very motivated for social contact and several stereotypic behaviours like waving and pacing could be related to frustration and the wish for contact with conspecifics. Many commercial products for environmental enrichments are now available, both with the aim to reduce boredom and to keep horses occupied in harmless activities when kept individually. How horses use such "toys" is however scarcely studied. We performed several studies to investigate issues related to paddocks and turnout. Our results show that horses were more active in large paddocks (10 x 45m), spending less time standing and more time walking, exploring and eating grass from under the fence than in small (10 x 15m) and medium sized paddocks (10 x 30m). Horses in the large paddocks also travelled a longer distance than in the small and medium paddock size. When kept in individual paddocks, the dominating behaviours during turnout were standing (51.5% of tot obs) and eating grass from under the fence (27.1%). Horses that were exercised daily for 45 minutes in a walking pace became more passive, spending more time standing (52.9%) and less time walking (5.1%) during turnout, compared to when not exercised (standing: 44.4%; walking: 9.2%). When kept in groups the same horses spent only 5.3% of their time standing and 74.4% of their time eating grass from under the fence. This is probably an effect of social facilitation. Very few incidents of aggressive interactions were recorded when the horses were kept in social groups, but bouts of social grooming were observed. The items that were edible (straw, ball filled with concentrates, branches) received the most attention from the horses regardless of being kept individually or in groups. Straw and a ball filled with concentrates were the most popular items. Peat, a plastic ball and a cone were investigated less than 0.5% of total observations. A scratching pole was used (1.7 - 2.2% of tot obs), but due to horses using it in rather short intervals, it was difficult to catch all events with our recording methods. The ability to eat grass was more important for reducing passive standing than the access to items, both for horses kept individually (correlation between eating grass and passive standing R=-0.97; P