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
Sammendrag
Cover crops are included in cropping systems to achieve various ecological benefits. In stockless organic cereal systems, nitrogen is commonly supplied by undersowing a legume shortly after sowing of cereals. Retarded growth of annual weeds is considered as an additional benefit of using cover crops. There is, however, less knowledge on the influence of undersown cover crops on the growth of perennial weeds. This issue was addressed in a field experiment at Ås in southeast Norway. For obtaining an experimental field with uniform distribution of the perennial weed species, root fragments of Cirsium arvense and Sonchus arvensis and rhizomes of Elymus repens, were transplanted by hand in the spring of 2001. A split plot design with 3 replications was initiated in 2002 and continued until the autumn of 2006. Barley undersown with red clover versus barley alone composed the two main plot treatments, except in 2006, in which barley was grown without red clover in the whole field. This was combined with four sub-plot mechanical treatments in the autumn: 1) untreated control; 2) mowing; 3) rotary tilling and 4) shallow ploughing plus harrowing. The autumn treatments were only carried out in 2004 and 2005. Number of weeds was counted at different dates throughout the growing season, and weed biomass was assessed just before harvest. Preliminary results indicate that red clover undersown in barley, compared to barley alone, reduced the biomass of established stands of S. arvensis by 50%, 42% and 13% in 2004, 2005 and 2006 respectively. The effect on E. repens varied from +10% in 2004 to -42% in 2005 and -50% in 2006. There was no suppression on established stands of C. arvense (+10%, 0 % and +70%). Of the autumn mechanical treatments rotary tilling and shallow ploughing most effectively retarded the growth of perennial weeds, especially C. arvense and E. repens. Rotary tilling and shallow ploughing reduced mean weed biomass for 2005 and 2006 of C. arvense by 80% (rotary tilling) and 40% (shallow ploughing), and E. repens by 77% and 89%, respectively. Mowing and shallow ploughing reduced mean weed biomass for 2005 and 2006 of S. arvensis most effectively, with a reduction of 62% for both treatments. Although the results need more attention before detailed recommendations can be given, the study indicates clearly that the effect of different mechanical treatments in the autumn depend on weed species.
Forfattere
Liv Guri Velle Samson ØpstadSammendrag
Ein gjennomgang av historia til utegangarsauen. Artikkelen tek føre seg eksempel på kvalitetar sauen har, driftsforma med heilårsbeite, nisjeprodukt og utfordringar.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce seedlings that had either wintered in nursery cold storage or had been planted out in autumn 2001. The damage was characterised by a top shoot dieback. Two visually distinct types of necroses were located either on the upper or lower part of the 2001-year-shoot. Isolations from the upper stem necroses rendered Gremmeniella abietina, while Phomopsis sp. was isolated mostly from the from the lower stem necroses. RAMS (random amplified microsatellites) profiling indicated that the G. abietina strains associated with diseased nursery seedlings belonged to LTT (large-tree type) ecotype, and inoculation tests confirmed their pathogenicity on Norway spruce seedlings. Phomopsis sp. was not pathogenic in inoculation tests, this implying it may be a secondary colonizer. We describe here the Gremmeniella - associated shoot dieback symptoms on Norway spruce seedlings and conclude that the unusual disease outburst was related to the Gremmeniella epidemic caused by the LTT type on large pines in 2001. The role of Phomopsis sp. in the tissue of diseased Norway spruce seedlings is yet unclear.
Forfattere
Arild AndersenSammendrag
Det er ikke registrert sammendrag
Forfattere
Stig Strandli GezeliusSammendrag
Det er ikke registrert sammendrag
Forfattere
Ingrid Holtsmark Dimitris Mantzilas Vincent Eijsink May Bente BrurbergSammendrag
Aim: To purify and analyse antimicrobial substances produced by the tomato pathogen Clavibacter michiganensis ssp. michiganensis (Cmm), with potential application in control of Clavibacter michiganensis ssp. sepedonicus (Cms), the causal agent of bacterial ring rot of potato. Methods and Results: After selection of a suitable producer and indicator strain, antimicrobial compounds were isolated using chromatographic techniques. The resulting preparations were analysed with respect to heat and protease sensitivity, amino acid composition, amino acid sequence and mass. Using this procedure we discovered one post-translationally modified 2145 Da peptide bacteriocin, one 14 kDa antimicrobial protein as well as low molecular weight (
Redaktører
Inger E. Måren Liv S. NilsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Peder Gjerdrum Mauro BernabeiSammendrag
Resin pockets, being an important natural characteristic for wood quality and tree physiology, were observed on the surfaces of boards sawn from four large Norway spruce (Picea abies (L.) Karst.) trees and analysed for size and distribution. Axial length varied between trees and increased from pith to surface and from butt to top; however, three quarters of the variation were random and normally distributed. Also resin pocket frequency varied between trees. Within the stem, the resin pockets remained independent and randomly distributed following the exponential distribution in all three directions: radial, angular and axial, corresponding to a constant probability during the lifespan of the tree. No association between size and frequency was identified. The initiation and the expansion of a resin pocket appear to be controlled by two different physiological processes. The findings should add to the understanding of resin pocket formation in spruce and should be applicable to wood quality
Sammendrag
Det foreligger fra før lite data om tiltaket tidlig lamming som et forebyggende tiltak mot rovdyrtap. Undersøkelsen bygger på to bruk i Tana i Finnmark som har prøvd denne metoden de siste fire år. Reduksjon i tap og økte inntekter ved å ha slaktemodne lam tidlig på høsten dekker merkostnadene ved økt fôrforbruk pga lengre innefôringstid etter lamming, og gir i tillegg et positivt økonomisk bidrag til merarbeid og ekstra huskostnader. Datagrunnlaget er basert i hovedsak på resultatet fra 2006, der de to forsøksbrukene er sammenlignet med et kontrollbruk i samme område.