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
Svein Ole BorgenSammendrag
Det er ikke registrert sammendrag
Forfattere
Arnstein Staverløkk May-Guri Saethre Eline Benestad HågvarSammendrag
The invasive ladybird, Harmonia axyridis Pallas 1773, is recorded for the first time in Norway. The specimen was found on horticultural plants imported from Aalsmeer in the Netherlands to Oslo, Norway. H. axyridis originates from East-Asia. The species is known to be a voracious predator on aphids and has been extensively used as a biological control agent in both North America and Europe. The later years, however, a number of negative impacts on the environment and biodiversity have been reported. The species was assessed as a potential bio-control agent for use in Norwegian greenhouses in 2001. The outcome of the assessment was negative with respect to import and commercial use in Norway. It was concluded that H. axyridis might survive and become established outdoors and thereby pose a risk to the environment. Recent experiences from the UK have shown that H. axyridis compasses several of the traits characterizing a successful invasive alien species. The record of this species in Norway may only be the first in a number of such, as it is likely that this species will survive outdoors, at least in the southern parts of Norway.
Forfattere
Arnstein Staverløkk May-Guri Sæthre Eline HågvarSammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. Aamlid Stein Jørgensen Lars Olav Breivik Ove Hetland Åsmund Bjarte Erøy Åge Susort Anne A. SteensohnSammendrag
Gjenlegg til økologisk engsvingelfrøeng bør sås samtidig med dekkveksten. Ni dagers utsettelse av såinga (til etter ugrasharving) førte til mer ugras (bl.a. balderbrå) og 11% reduksjon i frøavlinga i første engår. Virkningen av ulike dekkvekster varierte fra felt til felt, men i middel ble det oppnådd større frøavling ved gjenlegg uten dekkvekst eller i grønnfôr av bygg/ert, sammenlikna med gjenlegg i bygg, vårhvete eller erter til modning.
Forfattere
Svein SolbergSammendrag
Varmere vintre med flere dager med minimumstemperaturer over 0 °C vil paradoksalt nok kunne føre til en økning i frostskader på skog. Slike varme perioder vil redusere trærnes herdighet og toleranse for påfølgende frost. Klimaendringer kan på denne måten føre til en økning i omfanget av vinterog vårfrostskader, særlig i innlandet, samt en økning i klimatiske sviskader på gran i kyststrøkene i Sørøst-Norge.
Forfattere
Arnt Kristian GjertsenSammendrag
A multi-source forest inventory (MSFI) method has been developed for use in the Norwegian National Forest Inventory (NFI). The method is based on a k-nearest neighbour rule and uses field plots from the NFI, land cover maps, and satellite image data from Landsat Thematic Mapper. The inventory method is used to produce maps of selected forest variables and to estimate the selected forest variables for large areas such as municipalities. In this study, focus has been on the qualitative variables ‘dominating species group\" and ‘development class\" because these variables are of central interest to forest managers. A mid-summer Landsat 5 TM scene was used as image data, and all NFI plots inside the scene were used as a reference dataset. The relationship between the spectral bands and the forest variables was analysed, and it was found that the levels of association were low. A leave-one-out method based on the reference dataset was used to estimate the pixel-level accuracies. They were found to be relatively low with 63% agreement for species groups. An independent control survey was available for a municipality and estimates from the MSFI were compared to it. The levels of error were quite high. It was concluded that the large area estimates were biased by the reference dataset.
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Anna Arneberg Per Holm Nygaard Odd Egil Stabbetorp Bjarni D. Sigurdsson Edda Sigurdis OddsdóttirSammendrag
The aim of this study was to investigate variation in decomposition and vegetation due to afforestation. The ICEWOODS sites containing stands of different tree species and age in the western (Skorradalur) and eastern (Hallormsstaður) parts of Iceland were investigated during the summer of 2004. These stands were compared with treeless pastures. The planted stands represent chronosequences, i.e., different age classes within each tree species were studied. Decomposition was studied by a cotton strip assay. Cotton strip decomposition increased with incubation time and decreased with soil depth. The tree species can be ranked according to increasing decomposition in the following series: lodgepole pine < Sitka spruce< Siberian larch < mountain birch. In general, decomposition decreased with increasing age of the stands...
Forfattere
Philipp Gannibal Sonja Klemsdal Mark LevitinSammendrag
Alternaria tenuissima is a common pathogen on a number of plants described in several geographic regions of the world. Genetic variation within and between Russian Far East, North West and Caucasus populations of A. tenuissima from wheat was examined. In addition, genetic differences between isolates from various hosts were estimated. In total, 101 isolates of A. tenuissima were studied using amplified fragment length polymorphism (AFLP) with four primer combinations. Wright"s fixation index (F-st), gene flow (N-m) and gene diversity (H-s) were calculated. AFLP banding patterns indicated significant genetic distance and at the same time a low level of gene flow between the Far East and the two other groups of isolates originating from the European part of country. The degree of similarity between the North West and Caucasus populations was very high, as was the migration rate. Isolates analysed by UPGMA-based cluster analysis were grouped according to location of origin but irrespective of plant host. Based on the F-st value, the group of isolates originating from wheat and barley were not found to differ significantly from each other.
Forfattere
Zhihui Yang Bal Ram Singh Sissel HansenSammendrag
Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka(-1) and high level of 60 Mg ka(-1)) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1-2 mm) and microaggregates (<0. 106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5-1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5-1 and <0. 106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher ON, C/S and N/S ratios were found both in large dry aggregates (>20 and 6-20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0. 106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered.(C) 2007 Published by Elsevier B.V.