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.
2010
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
In Norway, Nordmann fir (Abies nordmanniana) and subalpine fir (A. lasiocarpa) are the dominant Christmas tree species, and noble fir (A. procera) the dominant bough plant species. To determine if fungi found to cause diseases on fir in Norway might be seed borne, samples from twelve seed lots, including Nordmann fir from Austria, Georgia and Russia, subalpine fir from Canada and Norway and noble fir from Norway were tested using agar plate methods (PDA and WA). The most important finding was that Sydowia polyspora was present on seed from all firs from all countries (nine samples infected, 0.5 - 85 % infected seeds). Recently, it has been demonstrated in Norway that this fungus is the cause of current season needle necrosis (CSNN), which is considered a major disease in the Christmas tree and bough production both in Europe and USA. Sirococcus coniguenus was found in a Norwegian A. procera seed lot (31% infected seeds), which to our knowledge is the first report of this pathogen on fir seeds. Caloscypha fulgens was detected on subalpine fir seed from Canada. In addition the following fungal genera were detected: Acremoniella, Acremonium, Alternaria, Aspergillus, Botrytis, Chaetomium, Cladosporium, Diaphorte, Dictyopolyschema, Epicoccum, Fusarium, Genicularia, Mucor, Neonectria, Penicillium, Phoma, Rhizopus, Sordaria, Trichoderma, Trichothecium, and an unidentified fungus.
Forfattere
Trond Rafoss Knut Sælid Arild Sletten Lars Fredrik Gyland Liv EngravsliaSammendrag
The threat posed by invasive alien species to global crop production and biodiversity is recognized as one of the major drivers of global change today. Here we report on a successful implementation and operational use of new technology to support risk- and crisis management in the case of fighting an invasive plant disease. The open geospatial standards Web Feature Service Transaction (WFS-T) was implemented in software for GPS-enabled mobile phones communicating with a GeoServer backend in order to track down and eradicate disease outbreaks and susceptible host plants. This new technology offering georeferenced events online from field provides new possibilities for real time action in risk and crisis management.
Forfattere
Trond HofsvangSammendrag
Two Malaise traps were set up at Ås, Southern Norway, during the growing seasons 1992-1997, one trap in an organic grown barley field and one in its boundary. Totally 23 species of Tipulidae (Diptera) were identified, of these eight species belonged to the genus Nephrotoma Meigen, 1803. Of the total specimens collected 93% of the males and 88% of the females belonged to this genus. Comparing the two traps, 80% of the Nephrotoma specimens were recorded in the organic field. It is discussed if larvae of Nephrotoma spp. in Norway can be potential pests in agricultural crops as reported from other countries. To Malaisefeller ble plassert ut i Ås i vekstsesongene 1992-1997, en i en økologisk dyrket byggåker og en i kanten av åkeren. Totalt ble 23 arter av stankelbein (Tipulidae, Diptera) identifisert, 8 av disse tilhørte slekten Nephrotoma. Av det totale antall individer som ble samlet inn, var 93 % av hannene og 88 % av hunnene av slekten Nephrotoma. 80 % av Nephrotoma-individene ble funnet i den fellen som sto ute i byggåkeren. I mange andre land er larver av Nephrotoma-arter skadedyr på mange kulturplanter i jordbruket, og det diskuteres om disse artene kan opptre som skadedyr i Norge.
Sammendrag
Abstract Two field trials are reported on Jerusalem artichoke (Helianthus tuberosus L.). Firstly, twenty genetic variants were compared with respect to crop yield, morphology and content of sugars and FOS in order to find genotypes suitable for Norwegian production. The highest yield and highest number of tubers per plant was obtained in early flowering variants, e.g. the white variant ‘Tysnes" gave 1.72 kg tubers per plant (28.7 t haa-1). Such early variants had markedly lower portion of smooth tubers. Late variants gave the most preferable tuber shape, but the yield was only half of the most productive ones. Dry matter content (%DM) varied from 19.67 to 23.33. Only a weak correlation was found between dry matter content and total content of FOS (r = 0.255) in the tubers. The mean content of FOS including sucrose through all variants was found to be 11.6 g 100g-1 FW or 55.0 g 100g-1 DW by measurement of non-hydrolyzed plant. Average chain length of FOS in the tubers was found to be DP3.9. There was no difference in tuber FOS content between flowering and non flowering variants. A second trial investigated the above ground part of one flowering and two late or non flowering variants during the growing season. Highest biomass was found for the late or non flowering variants when harvested in September. Total dry matter at time of harvest were found to be 0.21, 0.55 and 0,44 kg plant-1 for the variants ‘Dagnoytral", ‘Elverum" and ‘Krogerup" respectively (5.4, 14.1 and 11.3 t haa-1). At time of harvest stalks of ‘Elverum" and ‘Krogerup" contained 1.25 and 0.77 % fructose (DM) and 3.40 and 1.91 % sucrose. The content of soluble carbohydrates was found to be highest in stalks in August (sucrose and FOS major compounds).
Sammendrag
Peatland drainage results in several environmental impacts such as release of greenhouse gas to the atmosphere and leaching of nutrients to watercourses. These hazardous environmental effects can partly be controlled with soil management, and different drainage and remediation practices. Grading is a new method developed for soils with low conductivity suffering from poor drainage, water logging and ice. The soil surface is graded towards the ditch to increase surface runoff and drainage. The present study compares environmental effects of peatland grading compared to traditional intense pipe drainage. Detailed measurements of hydrology, climate, leaching and gas emissions were carried out at adjacent drainage areas with grass cultivation. Additional measurements were made at plots that were abandoned, cultivated with perennial crops, and remained as pristine peatlands. The results show that the leaching of nutrients is highest from pipe drainage. Climate gas emission was considerably higher at all managed sites than from the reference pristine site. Drainage, soil hydrology and soil nutrient status seemed to control gas emissions. The gas emissions were higher than assumed for Norwegian cold conditions. The results confirm observations made on peat soils in other climatic regions. The highest emissions of CO2 was observed when the soil temperature was high and groundwater table low. The N2O emission showed a large variation with no clear pattern. However, at some locations it peaked after a dry period when NO3-N was leached. More CH4 was emitted from the intensively drained site than the graded site, but more CO2 was emitted from the graded site. The difference in leaching and emission properties is partly due to differences in near surface hydrology. At grade sites, a faster runoff response to rainfall occur probably due to shallow throughfall or overland flow which provides better drainage. Also, the graded site was prepared recently, and this can have exposed fresh peat for decay. Therefore the drainage history must be well known in peatland studies as peat change in time due to drainage and cultivation. Abandoned peat field continue to leach greenhouse gases in a same way as cultivated sites.
Sammendrag
Transport and turnover of dissolved organic carbon (DOC) is important in the C cycle of organic soils. The concentration of DOC in soil water is buffered by adsorption to the soil matrix, and has been hypothesized to depend on the pool size of adsorbed DOC. We have studied the effect of frequent artificial excessive leaching events on concentration and flux of DOC in shallow, organic rich mountain soils. Assuming a constant Kd value for DOC adsorption to the soil matrix, we used these data to assess the change in the pool of adsorbed (or potential) DOC in the soil. The study involved manipulation of precipitation amount and frequency in summer and autumn in small, heathland catchments at Storgama, southern Norway. The shallow soils (16-34 cm deep on average) limit the possibility for changes in water flow paths during events. The mini-catchments range in size from 75 to 98 m(2). Our data show that after leaching of about 1.2 g DOC m(-2) the DOC concentration in runoff declines by approximately 50%. From this we conclude that the pool size of adsorbed potential DOC in the shallow soils at any time is of the order 2-3 g m(-2). Frequent episodes suggest that the replenishment rate, which depends on the decomposition rate of soil organic matter, is fast and the potential DOC pool could be fully restored probably within days during summer, but with some more time required in autumn, due to lower temperatures. Both pool size of potential DOC and replenishment rate are seasonally dependent. The pool of potential DOC, and thus the DOC concentration in discharge, is at their maximum in the growing season. However, under non-leaching conditions, the concentration of DOC in soil water and thus the pool size of potential DOC seems to level off, possibly due to conversion of DOC to less reversibly bound forms, or to further decomposition to CO2.
Forfattere
Aruppillai Suthaparan Arne Stensvand Sissel Torre Maria Herrero Rolf Inge Pettersen David Gadoury Hans Ragnar GislerødSammendrag
The effect of day length on production and germinability of conidia and severity of disease caused by Podosphaera pannosa, the causal agent of rose powdery mildew, was studied. Whole potted plants or detached leaves of Rosa interspecific hybrid 'Mistral' were inoculated with P. pannosa and exposed to 0, 12, 18, 20, 22, or 24 h of artificial light per day in growth chambers equipped with mercury lamps. Increasing duration of illumination from 18 to 20 to 24 h per day reduced production of conidia by 22 to 62%. Exposure to 24 h of illumination per day also strongly reduced disease severity compared with 18 h. Our results suggest that increasing day lengths from 18 h per day to 20 to 24 h may suppress the disease significantly and, thereby, reduce the need for fungicide applications against powdery mildew.
Sammendrag
Several places in Sogn og Fjordane county, W Norway, old pollarded trees of elm Ulmus glabra stand out as characteristic elements in the cultural landscape. These pollarded trees, which serve as habitats for many groups of organisms and are important key species in the cultural landscape, are threatened due to changes in farming management during the last century. In order to obtain more knowledge about the bryophyte flora on older elm pollards in Sogn og Fjordane county we examined two trees from each of four locations along an east-west gradient, from a strong oceanic climate in coastal areas towards slightly continental conditions further inland. Epiphytic bryophytes were recorded in three different height zones (basal, middle, and top) on the north, east, south and west sides of the trees. We looked for differences in species number (i) between the four locations, (ii) between three height zones (basal, middle and top) of the stems, and (iii) between different expositions (N, S, E and W) of the stems. We found 31 bryophyte species on the eight examined trees. No relation between geographic position and species number was found. There were significantly more species in the basal zones than in the middle zones, while there were no significant differences between the middle zones and top zones, or between the basal zones and top zones. The species number on the northern side exposition was significantly higher than on the eastern and southern sides of the stem.
Sammendrag
Norwegian agriculture has, as in most western-European countries, gone through several periods of change during the last 100 years. Pronounced changes have occurred in production systems and the spatial organisation of farm land, as well as agricultural policy. During the last 50 years, official statistics document a marked decline in the number of active farms. This decline has caused concern, as Norway traditionally has had an agricultural policy that emphasises self-sufficiency and rural settlement. Yet statistics also show that the amount of agricultural land in use has remained the same. This is usually explained through a larger proportion of tenanted land, as technological progress has allowed production levels to be maintained with a smaller workforce. Studies elsewhere in Europe show, however, that tenancy may not promote the same levels of investment and landscape management as owner occupation. To assess the potential impact of this change on Norway's landscape (and its value as both a cultural and tourism resource) we analyse tenancy patterns in Norwegian agriculture between 1999 and 2003. In particular we note that, even if owner occupation remains strong nationally, when the statistics are broken down by municipality, tenancy has increased significantly in some areas. This has left large areas of land managed as tenancies by a relatively small number of farmers, including parts of the iconic west coast fjords. We conclude therefore that further work is urgently required to establish whether the effects of tenancy seen elsewhere apply to Norway, whether this exposes key landscapes to increased risk of abandonment and if so what appropriate political responses there could be.