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.
2006
Forfattere
Ingerd Skow Hofgaard Åshild Ergon Birgitte Henriksen Hilde Kolstad Helge Skinnes Yalew Tarkegne Anne Marte TronsmoSammendrag
Abstract: Development of Fusarium head blight (FHB) was studied in winter wheat pre-treated with potential defence activators. Several chemicals were pre-screened for their capacity to reduce development of Microdochium nivale in a detached leaf as¬say. Selected compounds were further tested for their capacity to reduce Fusarium culmorum development in heads of winter wheat in greenhouse and field experiments. In the detached leaf assay, leaves from plants pre-treated with a foliar fertilizer displayed reduced disease development compared to untreated control. A significantly reduced disease develop¬ment of FHB in plants pre-treated with the foliar fertilizer was also registered in the greenhouse and field experiments. In the field experiment, harvested grains from plants treated with the foliar fertilizer had up to 75% reduction in Fusarium infected seeds com¬pared to grains from non-treated plants.
Forfattere
Leiv Mortensen Brita Toppe H.R. GislerødSammendrag
The influence of high CO2 concentrations and diurnal variation in air temperature on the development of powdery mildew (Podosphaera pannosa) was studied in different cut rose cultivars grown under 20 h day"1 supplementary lighting. An increase in CO2 concentration from 380 to 1000, or 2000 "mol mol"1, did not affect development of the disease in cvs. `Escimo" and `Red Champ". Compared to constant temperature, a temperature drop from 22 °C to 16 °C over the course of 8 h significantly enhanced the attack of powdery mildew in both cultivars, while the same drop in temperature over the course of 4 h had no effect. In another experiment, a temperature increase from 20 °C to 26 °C reduced the attack of powdery mildew in the four cultivars studied (`Escimo", `Red Champ", `Jade" and `Cezanne") when applied over 4 h and even more so when applied over 8 h. Number of days until flowering was unaffected by CO2 concentration, but was increased by a drop in temperature and decreased by a rise. Fresh weight per shoot was increased by CO2 enrichment, a drop in temperature and by a 4 h period of increased temperature. The results are discussed in relation to an optimal greenhouse climate with respect to rose production and powdery mildew control.
Forfattere
Nils-Otto KitterødSammendrag
Statens vegvesen ønsker å sette i gang undersøkelser hvor for-målet er å dokumentere sikkerhets- og iljømessige effekter knyttet til avisning av norske vinterveier. I dag benyttes stort sett veisalt (NaCl) for visning, men det finnes også andre al-ternativer kjemikalier på markedet. Aktuelle stoffer er Kalsium/Magnesium Acetat (CMA) og Kalium-Formiat (KFO), Kali-um-Acetat, Magnesiumklorid og diverse blandingsprodukter der polysakkariner inngår som "klebemiddel". Undersøkelsene vil omfatte både friksjonsmålinger og miljøeffekter. Før even-tuell omlegging av avisningspraksis, må det dokumenteres at alternative avisningsmidler ikke gir dårligere friksjon enn vei-salt. Det må også dokumenteres at alternative avisingsmidler ikke har mer skadelig effekt på miljøet enn vanlig veisalt. Fo-kus i denne rapporten er de miljømessige effektene. Hensik-ten er å spesifisere geohydrologiske kriterier for valg av for-søksfelt som er best mulig egnet for å observere miljøeffekter av avisningsmidler. Planen er å dokumentere effekter både av vanlig veisalt og alternative avisningsmidler. Det er et krav fra Statens vegvesens side at forsøkene blir planlagt på en slik måte at det lar seg gjøre å trekke konklusjoner som er gyldige ut over det området som blir overvåket. Dette innebærer at forsøkene må kobles til matematiske modeller som simulerer miljøresponsen. Kriteriene i denne rapporten er derfor først og fremst rettet mot hvilke parametere som må observeres for at slike strømningsmodeller kan bli kalibrert og validert.
Forfattere
Marianne BechmannSammendrag
Raske og effektive reduksjoner i fosfortilførsler til ferskvann fra dyrka mark kan oppnås dersom en fokuserer på de arealene som bidrar med de største tapene. Det krever både kunnskap om prosesser som fører til fosfortap, og et verktøy som kan kartlegge arealene, slik at kunnskapen blir tilgjengelig for gårdbrukere, rådgivere og evt. myndigheter. Fosforindeksen er et slikt verktøy som kan brukes til å rangere arealer i relasjon til fosfortap. Den er basert på informasjon for hvert skifte om bl.a. erosjonsrisiko, fosforinnhold i jorda, driftspraksis og avstand til vassdrag. Indeksen er basert på opplysninger som er tilgjengelige for alle bønder i gjødselplan eller fra statistiske kilder. I tiltaksplanlegging på gårdsnivå kan fosforindeksen brukes som hjelpemiddel for å vurdere de mest effektive tiltak. Fosforindeksen er utviklet og brukt i praksis i U.S.A. I Danmark satses det nå storstilt på å bruke et lignende prinsipp i vannforvaltningen. I Norge er fosforindeksen tilpasset og testet for kornarealer på Østlandet (Dr. grad fra 2005) og det jobbes med å videreutvikle den for andre arealer med mål om å kunne ta den i bruk som et praktisk verktøy
Sammendrag
Transient starch production is thought to exert a strong control over plant growth and response to elevated CO2. Here we tested this hypothesis with an experimentally-based mechanistic model in Arabidopsis thaliana. " Experiments were conducted on wild type (WT) of A. thaliana, starch-excess and starchless mutants under ambient- and elevated-CO2 conditions to determine parameters and validate the model. Central to the model, we experimentally demonstrated that dark respiration is directly proportional to soluble sugar concentration in A. thaliana leaves. " The model correctly predicted that: 1) mutant growth is about 20% of that of WT, and 2) absolute response of both mutants to elevated CO2 is an order of magnitude lower than that of the WT. " Our study demonstrates that effects of the diurnal starch cycle on growth can be captured by a fairly simple set of allocation equations. Our results further suggest that the maximum rate of leaf growth, and broadly the sink capacity, exert a strong control over the response to elevated CO2 of herbaceous plants such as A. thaliana.
Forfattere
Ingvild Wartiainen Anne Grethe Hestnes Ian R. McDonald Mette M. SvenningSammendrag
A Gram-negative, rod-shaped, non-motile, non-spore forming bacterium (SV96T) was isolated from wetland soil near Ny-Ålesund, Svalbard. On the basis of 16S rRNA gene sequence similarity, strain SV96T was shown to belong to the Gammaproteobacteria, related to Methylobacter psychrophilus Z-0021T (99.1 %), Methylobacter luteus ATCC 49878T (97.3 %), Methylobacter marinus A45T (97.0 %) and Methylobacter whittenburyi ATCC 51738T (95.8 %); the closest related species within the genus Methylomicrobium with a validly published name was Methylomicrobium album ATCC 33003T (95.0 %). Chemotaxonomic data (including the major fatty acids: 16 : 1v8, 16:1v7 and 16:1v5t) supported the af"liation of strain SV96T to the genus Methylobacter. The results of DNA"DNA hybridization, physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain SV96T from the four Methylobacter species mentioned above. Strain SV96T therefore represents a novel species, for which the name Methylobacter tundripaludum sp. nov. is proposed (type strain SV96T =DSM 17260T = ATCC BAA-1195T).
Forfattere
Kåre Rapp Gunnlaug Røthe Christian Uhlig Ivar SchjelderupSammendrag
Modern human activities, as power plant building, mineral exploitation and military exercises, increasingly damage landscapes in Northern regions. Correspondingly to the increasing extent of Northern ecosystem disturbance there is a greater than ever need for appropriate plant material and restoration methods. This paper summarizes fifteen years of plant breeding and practical restoration efforts in Northern Norway. The work started in 1992 by collecting twenty-one different plant species, including a total of sixteen graminoids, one herbal and four lignose species. The majority of selected plant species were propagated of seeds, except for Salix sp. and Poa alpine, which were propagated vegetative. Since the year 2000 seven selected populations of graminoids, including Festuca ovina, F. rubra, Poa pratensis, Deschamsia cespitosa and Alopecurus pratensis are seed produced in Alta (69° N). Seeds produced in Alta are recently used in restoration projects in Finnmark and Troms County and first results from these sites will be presented. Furthermore, seeds produced in Alta will soon be available for commercial use.
Forfattere
Hugh RileySammendrag
Changes in soil organic matter (SOM) content are presented for a 25 ha research farm, based on measurements in 1952, 1976, 1986 and 2002, and for 291 arable fields located throughout southeast Norway, which were sampled in around 1991 and again in 2001. Large declines were found in most cases at the research farm, especially for soils with high initial levels of SOM. The declines between 1952 and 1976 were thought to be partly due to increased depth of ploughing and improved drainage, whilst those in the latter period may in part be related to climatic change. Declines were also found since 1990 in the majority of the arable fields sampled, and the declines were proportional to the initial SOM level in this case also. No single causative factor was isolated for these declines, but the proportions of autumn tillage and of row crops in the rotation may be involved. A mean relative decline rate of around 1% per year of the initial SOM level was observed both at the research farm and in the arable fields. There was, however, also an indication that the percentage relative decline rate was proportional to one tenth of the initial SOM. These two alternative scenarios suggest that soils with current SOM levels of 4%, 6% and 10%, will reach a possibly `critical" level of 3% in 30-80, 70-165 and 120-230 years time, respectively.
Forfattere
Marit JørgensenSammendrag
In this study four Norwegian white clover cultivars were compared with the Danish variety Milkanova under farm site conditions in the different climatic conditions of Norway. A series of field experiments were established with five different white clover cultivars sown in grass mixtures. The swards were defoliated at a sward height of 20 cm to simulate grazing. There were no clear differences in yield production or clover content between the cultivars in the southerly/lowland regions when averaged over three years. Milkanova is a relatively high yielding variety, but has a poor overwintering capacity. The grass/clover mixtures containing Milkanova had the highest yield in the first years of the experiment, but the yields declined and tended to be lower than other cultivars in the third year, with significantly lower clover content. In the alpine/northerly regions, grass/clover mixtures containing Milkanova had lower yield, and lower clover content from the start of the experiment. Both protein, ash and NDF contents were closely linked with white clover content in the swards; with more protein and ash less NDF in plots containing more clover. Feed quality was lower in 3rd cut than in 1st cut.
Forfattere
Anne Kristine SøvikSammendrag
Filter beds and constructed wetlands (CWs) treat municipal wastewater through retention of nutrients and particles. Retention of nitrogen (N) in filter beds was studied in the laboratory using columns and meso-scale trenches filled with shellsand and light-weight aggregates (LWA). The objective was to examine whether measuring the natural abundance of "15N in NO3- could be used to estimate denitrification in these systems. In both the columns and the trenches, it was seen that denitrification was more efficient in shellsand and LWA collected from field scale filter beds compared to raw LWA. This was due to the high pH value (about 10) of raw LWA. The enrichment factors (") from the column study was in general lower than values found in laboratory tests of isotope discrimination in denitrification, but similar to " values found for denitrification in groundwater systems. No enrichment factors could be found for the trench study due to simultaneous denitrification and nitrification. When NH4 was partially nitrified in the upper parts of the trench, this diluted the 15N enrichment of NO3- due to denitrification. Thus in systems with high NH4 concentrations, and partial aerobic conditions, the method of natural abundance is not suitable for estimating denitrification.