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.
2002
Sammendrag
Sheep and goat farming systems in this part of Europe are based on extensive use of non-fertilised natural pastures and a long barn-feeding period. One million ewes are kept for the production of meat and wool while 60,000 goats are kept mainly for themilk. The local demand for organic meat and milk is increasing gradually and 10 percent of the agricultural area is projected to be managed according to organic principles by 2010. This paper discusses the feasibility of introducing cashmere goats in an organic sheep farming production system, based on economical calculations in a Linear Programming model. Significant movements from sheep to cashmere goats production are entirely as slaughtering of eight months old kids (11 kg) is unprofitable, assuming equal labour input of goats and sheep. Yields of meat and cashmere could be improved by feeding the kids until 20 months (19 kg) so possibly making goats as profitable as sheep. The benefits of high value cashmere production and controlling bush encroachment by goats favour a mixed farming system. If yield-levels of roughage can be maintained at 75% without artificial fertilizers and challenges in housing of small ruminants are solved, a shift away from conventional farming is profitable given the current support for organic farming.
Forfattere
Halvor SolheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Nicholas ClarkeSammendrag
In natural waters, total organic carbon (TOC) is the sum of particulate and dissolved organic carbon. Dissolved organic carbon (DOC) is operationally defined, usually as organic carbon that passes through a 0.45 µm filter. Cellulose acetate or nitrate filters should not be used for this purpose due to contamination or adsorption problems. Glass fibre filters are preferable. Although the discussion below concerns DOC, much of it applies to TOC as well. Organic carbon is most often determined after oxidation to CO2 using combustion, an oxidant such as persulphate, UV or other high-energy radiation, or a combination of some of these. If only UV radiation with oxygen as oxidant is used, low DOC values may be obtained in the presence of humic substances. A variety of methods are used for detection, including infrared spectrometry, titration and flame ionization detection after reduction to methane. Always follow the instrument manufacturer’s instructions. For determination of dissolved organic carbon, dissolved inorganic carbon must be either removed by purging the acidified (for example with phosphoric acid) sample with a gas which is free from CO2 and organic compounds, or determined and subtracted from the total dissolved carbon. If acidification followed by purging is used, care should be taken as volatile organic compounds may also be lost. After acidification, remove CO2 by blowing a stream of pure carbon-free inert gas through the system for at least 5 minutes. Carbon is ubiquitous in nature, so reagents, water, and glassware cannot be completely cleaned of it. Method interferences (positive bias) may be caused by contaminants in the carrier gas, dilution water, reagents, glassware, or other sample processing hardware (for example a homogenization device). All of these materials must be routinely demonstrated to be free from interference under the conditions of analysis by running reagent blanks. Plastic bottles can bleed carbon into water samples, especially when they are new, or when they are used for low-level samples (less than 200 ppb C). Any new bottles (especially plastic) should ideally be filled with clean water for a period of several days or boiled in water for a few hours before use. The use of high purity or purified reagents and gases helps to minimise interference problems. It is very important to use ultra-pure water with a carbon filter or boiled distilled water just before preparing stock and standard solutions, in order to remove dissolved CO2. The stock solution should not be kept too long (about one week). For most DOC instruments a correction for DOC (due to dissolved CO2) in the dilution water used for calibration standards is necessary, especially for standards below 10 ppm C. The carbon in the blank should only be subtracted from standards and not from samples. For calibration, standard solutions are most often potassium hydrogen phthalate for total dissolved carbon and sodium bicarbonate for dissolved inorganic carbon. The DOC concentration should be within the working range of the calibration. If necessary the sample can be diluted. Sample DOC below about 50 ppb C can be affected by atmospheric exposure. In these cases, sampling bottles should be kept closed when possible, and autosampler vials should be equipped with septa for needle piercing by the autosampler.
Sammendrag
Det er analysert 18 askeprøver fra 5 biobrenselanlegg. De kvantitativt viktigste makro-elementene i aske fra biobrensel er kalsium (23,3%), kalium (8,34%), magnesium (3,25%), mangan (1,47%), fosfor (1,03%) og svovel (0,93%). Asken inneholder også viktige mikronæringsstoffer som sink, kobber, mangan og bor. Innholdet av viktige næringsstoffer er relativt høyt og gjør at asken har et brukspotensiale som gjødselkilde i tillegg til gode kalkingsegenskaper. Variasjonen i kjemisk sammensetning av asken innen hvert enkelt biobrenselanlegg varierer betydelig, men er mindre enn variasjonen mellom anleggene. Det er til dels store forskjeller i sammensetning av aske fra forskjellige anlegg også der hvor samme type pellets er brukt. Ved anvendelse av aske i skogsjord er effektene i første rekke knyttet til en økning i pH (økt nitrogen-mineralisering) og mindre til tilførsel av næringsstoffer. Effektene av økt pH i skogsjord er trolig avhengig av karbon/nitrogen-forholdet i jorda. Ved lave karbon/nitrogen-forhold vil nitrogen-mineraliseringen øke etter asketilførsel med muligheter for økt N opptak hos planter og økt nitratavrenning. Tilgjengeligheten av de tungmetallene som tilføres jord med aske kan både øke og avta. Generelt avtar tilgjengeligheten av de fleste metaller med økende pH, men pga ionebytteeffekter kan tilgjengeligheten øke (for eksempel ionebytte Cd/Ca). I en rekke forsøk er det påvist at tilførsel av ren CaCO3 øker opptaket av Cd i jordbruksvekster like mye som ved tilførsel av aske. Effektene i jord på kort og lang (5 år) sikt er vist å være svært avhengig askens herdingsgrad og pelleteringsform da disse faktorene vil påvirke reaksjonshastighet (bufrings- og ionebyttereaksjoner) og tilgjengelighet av næringsstoffer. Dersom aske fra biobrensel skal anvendes i større grad enn i dag vil det være behov for behandling av asken. Herding dvs. ved innblanding av vann (optimalt 30-40%) i asken, oppnås en større hardhet, mindre støving og bedre spredningsegenskaper. Erfaringer fra Sverige og Finland viser at herding er mer kostnadseffektivt enn granulering og pelletering. Den beskjedne bruken av aske i Norge er ikke i første rekke relatert til askens sammensetning og begrensninger i gjeldende lovverk, men til forhold knyttet til små og geografisk spredte anlegg (små askevolumer), logistiske begensninger, rimelige deponeringsløsninger og dermed manglende motivasjon og behov til å tenke helhetlig innen biobrenselbransjen.
Forfattere
Bernt-Håvard ØyenSammendrag
Vekst og utvikling i utynnet granskog på Vestlandet er undersøkt. Materialet består av 34 forsøksruter fra langsiktige forsøksfelter som er fulgt med gjentatt tremålinger i mange tiår. Hovedtyngden av materialet er yngre bestand, men opp til 70 år gamle plantefelt er representert. Foreløpige produksjonstabeller og algoritmer som kan benyttes for å beskrive utvikling og produksjon i utynnede bestand er presentert. Utynnet granskog kan beskrives med følgende stikkord: forsiktig start, høg tetthet og produksjon, liten avgang, stor spredning på diameter, god stabilitet. Modellene indikerer at kulminasjon av volumtilvekst inntreffer 30-50 år tidligere i utynnede sammenlignet med tynnede plantefelt.
Forfattere
Bernt-Håvard Øyen Petter NilsenSammendrag
Growth effects in a sub-alpine, low-yield Norway spruce forest in southeast Norway are reported. Sixteen sample plots of 400 m2, established 8-9 years after a mountain forest selective (MFS) cutting in the mid-1970s, were re-investigated in 2000. The selective cutting was heavy, with a mean felling volume of 72 per cent of the standing volume. Most trees in the remaining stands responded positively with increased growth after the cutting, and this was most pronounced in small and medium sized trees. A weak relationship between standing volume before and after felling, and the actual stand volume increment in the 25-year period was revealed. The felling has stimulated natural regeneration and increased the proportion of birch. The results indicate that not more than ~65 per cent of the standing volume should be cut in a single intervention if cutting cycle is less than 50 years.
Forfattere
Lars Sandved Dalen Carl Gunnar Fossdal R. Bhalerao John Beck Jensen Teemu H. TeeriSammendrag
Trees cover over one-third of the world\"s land area and carry out about two-thirds of global photosynthesis. Coniferous forests cover 1.2 billion hectares of Alaska, Canada, Scandinavia, and Russia, and comprise one-fourth of the world\"s boreal and temperate forests. More than 50% of Scandinavia\"s land area consists of forests, mostly coniferous. Information about the molecular responses in trees to biotic and abiotic factors is therefore of great importance - both scientifically and practically. Generation of expressed sequence tags (ESTs) is an important part of genome research. Randomly selected cDNA clones are partially sequenced, and the ESTs reflect the level and complexity of gene expression in the sampled tissue. In order to find interesting gene products and to study gene expression in the most common and economically important conifer in the Nordic countries, we have started an EST-project on Norway spruce. So far we have sequenced ~3500 cDNA clones based on mRNA isolated from needles and cell cultures. Here, we present the frequency of the different ESTs, their putative function and their functional classification. We aim at sequencing another 20,000-30,000 cDNA-clones from wood-forming tissues and from seedlings treated with drought, low temperatures, pathogen infection, etc. The long-term goal is to develop a non-redundant and annotated collection of Norway spruce clones to be used in combination with microarray analysis
Sammendrag
The project reported here was a co-operation between the National Focal Centers for four of the ICPs in Norway: ICP Mapping and Modeling, ICP Waters, ICP Forest and ICP Integrated Monitoring. Dynamic modeling was carried out using data from several sites in the ICP networks, with the aim of making predictions on the future acidification status for surface waters, forest and soils in Norway. Predictions are made for three different deposition scenarios. At two of the sites, the model predictions suggest that the Current Legislation scenario will not promote water qualities sufficient for sustainable fish populations, while the scenario seems sufficient for the others. Under the Maximum Feasible Reduction scenario one of the sites still will not reach a sufficiently high ANC. In general, the modeling results for forest soils agree with results from previous investigations stating that surface water acidification is more severe than the soil acidification. However, the results suggest that there has been soil acidification at all sites as a result of acid deposition and that the base saturation will not be built up again to pre-industrial levels during the next 50 years at any of the sites, not even with the Maximum Feasible Reduction Scenario.
Sammendrag
Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way to monitor fungal hyphae within the host is microscopic examination, but chitin and ergosterol-levels are commonly used to indirectly measure the amount of fungus present. Recently real-time PCR technology is being used to follow infection agents in host tissues. We study the molecular basis of host defense responses, using the coniferous host Norway spruce infected with the pathogen Heterobasidion parviporum as the experimental system. This basidiomycete and the closely related pathogen H. annosum are the major root rot causing pathogens in conifers. To screen host material for differential resistance towards H. parviporum, it is a necessity to quantify the fungal colonization of the host tissues. Therefore, we aimed to develop and compare the sensitivity of a real-time PCR to an ergosterol based method for determining the rate of colonization, and applied the methods to rank the infection level of the pathogen on the spruce clones 053 and 589. We developed a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H. parviporum DNA and 1ng host DNA. There was a very high correlation between the fungal-biomass/total-biomass and fungal-DNA/total-DNA rankings obtained with ergosterol and real-time PCR, strengthening the credibility of both methods. Based on both ergosterol and real-time PCR, it was clear that the clone 053 was hosting more fungal biomass than clone 589. The results indicate that this real-time procedure can be a useful method to screen different spruce material for their relative resistance to the pathogen H. parviporum.
Sammendrag
Several strong westerly storms hit Western Norway during the winter of 1986-87. We studied the uptake, loss and visible effects of sea salt aerosols in Scots pine and Norway spruce. Foliage of was sampled at distances 0-100 km from the coastline between 59¢ª and 65¢ª N, and analysed for chloride, sodium and other elements. The range of chloride and sodium concentrations in needles was 0.5-5.0, and 0.1-3.0 mg g-1, respectively. The local variation was very large close to the coast. The relation to distance from the sea was improved by using distance from the nearest fjord rather than from the outer coastline. Other elements were less variable and not related to distance from the sea, or to sea salt concentrations. Only 1-10% of the needles sea salt content could be removed by 2 minutes washing in distilled water, and still much less of other elements. The amount of sea salt removed by washing was less related to distance from the sea than was the total content. Visible damage to the foliage occurred at chloride concentrations above 1 mg g-1 in the needles. Our conclusions are that analysis of the needles chloride or sodium content is a robust method for confirming damage to tree foliage by sea salt aerosols. Fjords as well as the ocean are significant sources of sea salt aerosols. Large local variation in salt deposition and damage will occur at a rugged coast. Nutrients and other elements are not significantly affected by the sea salt deposition. The use of chloride or sodium as a tracer for dry deposition should take into account not only the enrichment of these elements in canopy throughfall, but also the accumulation in the needles.