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.
2005
Sammendrag
Hydraulics of subsurface flow filters (SSF) was studied by measurement of soil hydraulic conductivity (K) variation and performing tracer tests in two SSF filters consisting of 1-4 mm Ca rich sand (shell sand). Soil samples were carefully taken at several locations in Filter I. A tracer experiment was conducted in the undisturbed Filter II using KI. The measured K variability in Filter I was used to analyze the variations in tracer breakthrough. The spatial distribution of K was obtained by fitting a variogram to observed data and interpolation using Kriging. The tracer residence probability density function (PDF) was determined by modelling the tracer movement with a 3-D groundwater model. The observed and simulated tracer arrival was compared for cases with constant K, constant K and dispersion (D), and for spatially variable K and dispersion. The results show that groundwater models were well suited to simulate solute movement in the SSF system studied. An almost perfect fit to observed tracer PDF was obtained when variable K and dispersion was included in the model. This indicates that information on K variability and dispersion is important for studying solute movement in SSF constructed wetlands.
Sammendrag
Controlled experiments were carried out in a meso-scale sub-surface flow constructed sand filter treating municipal wastewater from a single household. The system consisted of a 50 cm high vertical flow column (pre-filter) with unsaturated flow and a 3 m long horizontal sub-surface flow unit (main filter) with saturated flow. Fluxes of nitrogen and carbon were analysed in four different operating conditions (low and high loading, with and without the pre-filter unit). Water samples were taken from the inlet, the outlet and within the sand filter at different depths and locations and analysed for water quality (Tot N, NO3-N, NH4-N, TOC, DOC, CODcr, BOD5, SS, pH and EC) and dissolved gas content (N2O, CH4 and CO2). Emissions of N2O, CH4 and CO2 were measured with the closed-chamber technique adjacent to water quality sampling points. The results show that pre-filtering in a vertical, unsaturated flow column changed the incoming ammonium to nitrate during low loading. During high loading part of the ammonium nitrified in the pre-filter was lost by denitrification. Within the horizontal main filter there were two pathways for the incoming nitrate: denitrification and dissimilatory nitrate reduction to ammonium (DNRA).
Forfattere
Øyvind Nordli Finn Måge Frans-Emil Wielgolaski Stein Harald Hjeltnes Anne Kjersti Bakken Oddvar Skre Endre SkaarSammendrag
The analyses are based on phenological observations carried out at international phenological gardens (IPG) at Fana (western Norway) and Kvithamar (Trøndelag), also at the Norwegian University of Life Sciences (Ås, south-eastern Norway) and the research station Njøs (Sogn, western Norway). The longest series are from Njøs (1927) and Ås (1947), whereas no series at the IPGs is older than 1964. For the three southernmost sites (Ås, Fana, and Njøs) all trends are negative, i.e. there has been a change towards earlier occurrences of the phenophases in spring. For the northernmost site (Kvithamar) also positive trends are seen. Four species are cultivated at Fana as well as at Kvithamar. For these species the trend lines are steeper at Fana than at Kvithamar. For the longest series (1927 - 2005) the trend is only -0.4 day/decade but insignificant (p > 0.05). This amounts only to about 3 days earlier occurrence (apple at Njøs) within this period of 79 years. The trend at Ås (1947 - 2005) is also insignificant, although it amounts to about -1 day/decade or about 6 days earlier occurrence within the 59 year period.
Sammendrag
The objective of this study was to examine the effects of increasing temperature (+2-2.5°C) and CO2 (370 ppm vs. 550 ppm) and 30% shading compared to outdoor conditions on autumn growth of a northern (63°N) and a southern (59°N) ecotype of Elymus repens (L.) Gould, Cirsium arvense (L.) Scop. and Sonchus arvensis L. Pieces of rhizomes (E. repens) and roots (C. arvense, S. arvensis) were planted in pots in May 2004 and grown outdoors at 58°N until the start of the experiment in September. The plants were cut to 20 cm height before start of experiment. Every fortnight developmental stage, leaf area, dry weight of above ground and belowground plant parts, and root/rhizome length were assessed. After cutting, E. repens regrew with new shoots and more leaf area until the end of the experiment, while S. arvensis withered shortly after the start of the experiment. C. arvense held an intermediate position with small regrowth on the existing shoots, while leaf area decreased. The southern ecotype of S. arvensis and C.arvense developed more roots than the northern ecotype with a corresponding lower shoot/root-ratio. The southern ecotype of C. arvense also produced more leaf area. The northern ecotype of E. repens developed more leaf area and shoot and root/rhizome dry weight. The leaf area and shoot dry weight averaged over all species, and the leaf area of E. repens and C. arvense increased with increasing temperature and shading. Elevated CO2 increased the leaf area of E. repens. Since the roots/rhizomes were little affected by changes in autumn climate, it is expected that next year"s infestation level is also not greatly influenced.
Forfattere
Åsmund AsdalSammendrag
Norsk flora inneholder ca 2500 karplanter og av disse finnes 6-700 arter i enger og grasmarker. Ca. 350 finnes bare i disse biotopene, og mange arter har øknomisk eller kulturell verdi. For norsk landbruk er spesielt fôrvekstene av gras eller kløver viktige. Aktiv bruk av grasmarkene for beiting eller fôrslått reduseres dramatisk i Norge, noe som reiser bekymring for forekomst av arter som finnes i disse engene, og for den genetiske variasjonen innen artene, som blant annet framtidig foredling vil være avhengig av. Husdyrhold i Norge startet for ca 6000 år siden, og beiting og slått har påvirket genetisk utvikling og tilpasning i engartene slik at vi i dag har unike genotyper som ikke finnes i vill flora. Genetisk mangfold i disse artene er ikke godt undersøkt, men innsamlinger av frø fra populasjoner ulike steder i landet er gjennomført i regi av NGB. I tillegg til fôrvekstene er disse engene voksested for andre nytteplanter, som feks. krydder- og medisinvekser, slektninger til nytteplantene og arter som har potensiale til å bli brukt mer. Deres forekomst in situ vil være avhengig fortsatt landbruksdrift. Studier har vist at hvis den tradisjonelle landbruksdriften opphører endres artssammensetningen i engene og når endringen er skjedd er det så og si umulig å gjenskape den opprinnelige floraen, og genressurser vil være tapt for alltid. Det er også viktig å merke seg at floraen i beitemarker skiller seg mye fra slåtteengenes flora. Beitemark inneholder mer grasarter, mens slåttemarker har mer urter og tpfrøbladete arter. Slåtteenger domineres av arter som blomstrer tidlig, mens beiteenger generelt har mindre blomsterprakt og artene blomstrer senere. For å hindre utryddelse av artene og deres genetiske variasjon har det Norske Genressursprogrammet initiert prosjekter for å sikre fortsatt drift av verdifulle engarealer. I en pilotfase er verdifulle enger kartlagt for flora og aktuell jordbruksdrift, og det er vurdert om ulike virkemidler kan benyttes for å sikre fortsatt drift.
Sammendrag
To better understand N cycling in white clover (Trifolium repens L) stands under northern climate conditions, we studied how harvesting regime affects plant longevity and N content in late autumn, ability to conserve N during winter and the fate of the lost N. Several field experiments were performed throughout four consecutive years using white clover plants (cv "Snowy") that were established from stolon cuttings or seeds. During the growing season, plants were treated and sampled destructively in late autumn, early spring the second year and after six weeks of new spring growth. Dry weight and N concentration were measured on all fractions. On additional experiments the longevity of main plant organs were monitored during two years and seepage water percolating throughout the above ground plant biomass was collected during four years. For harvested plants the repeated leaf removal and subsequent regrowth came at the expense of stolon- and root development and resulted in a reduced total plant N content in late autumn. During winter, root N was quite stable, as certain root dormancy occured, while approximately 80 % of the N present in leaves in autumn was lost - independent of treatment. Short leaf lifespan (less than 100 days) indicated that leaves are not genetically programmed to survive winter. Losses of N from stolons were lower, however, harvesting regime affected both the longevity and N losses. The amount of inorganic N in soil after snowmelt and mineralization of white clover-derived N through spring was low indicating that leaching and gas emissions might be important N pathways. The 26 % of lost N was found in seepage water.
Sammendrag
Lite forskning har vært gjort på forsvinning av pesticider under kalde klimaforhold, og det er behov for å fokusere på effekten av klima på nedbrytning av pesticider i jord. Glyfosat, N-(phosphonomethyl)glycine, er et herbicid som er hyppig brukt for å bekjempe flerårig ugras ved sprøyting etter høsting, og er brukt som modell-middel i denne studien. Effekten av fryse-tine aktivitet på tilgjengelighet av glyfosat i jord, og følgelig dets mineralisering av jordmikrober, ble undersøkt ved laboratorieforsøk hvor pakka jordsøyler behandla med 14C-merka glyfosat ble utsatt for ulike fryse-tine behandlinger. Ulike vinterforhold som ble simulert var konstant temperatur over frysepunktet (+5°C), konstant frost ("5°C), ustabile forhold med korte temperaturfluktuasjoner (24 t ved +5°C fulgt av 24 t ved "5°C), og langvarige fluktuasjoner (3 uker ved +5°C fulgt av 3 uker ved "5°C). Fordelingen av 14C-glyfosat ble fulgt gjennom inkubasjonsperioden ved målinger av mineralisert fraksjon (14C-CO2), jordvannsfraksjonen, KOH-ekstraherbar fraksjon og ikke ekstraherbar fraksjon. De mikrobielle parametrene som ble brukt for å karakterisere jorda var mikrobiell biomasse, generell mikrobiell aktivitet og mikrobiell diversitet. Behandlingen med konstant frost ga lavest mengde glyfosat mineralisert. Behandlingene med konstant temperatur over frysepunktet og fluktuasjoner i temperaturen viste signifikant høyere glyfosatmineralisering. Disse resultatene var i samsvar med de observerte konsentrasjonene av glyfosat i jordvannet; jo hlyere aktivitet, jo lavere konsentrasjon. Mengde KOH-ekstraherbar glyfosat og den resulterende ikke-ekstraherbare fraksjonen, var imidlertid ikke signifikant påvirket av prøvetakingssted (jordprøve) eller temperaturforhold. Mønsteret i glyfosatmineraliseringen var sammeliknbar med den generelle mikrobielle aktiviteten i jorda. De observerte ulike nivåene av mikrobiell diversitet kan forklare noe av forskjellene i total mengde glyfosat mineralisert mellom jordprøvene.
Forfattere
Jens Rohlof Steinar Dragland Ruth Mordal Tor-Henning IversenSammendrag
In the period from 2000 to 2002, studies on peppermint ( Mentha piperita) herb and essential oil (EO) production have been conducted at Planteforsk, Apelsvoll Research Centre Div. Kise in Norway. The trials were aimed at finding the optimal harvest date and suitable drying methods to maximize EO yield and to obtain a desirable oil quality. Peppermint plants from the first production year (2000 and 2001) and the second production year (2002) were harvested during flowering at three developmental stages (early, full, and late bloom). Biomass and leaf production were recorded, and the water content of the plant material was detected after the application of different drying methods: instantaneous drying at 30, 50, and 70 °C and prewilting (ground drying) for 1 or 5 days followed by final drying at 30 °C. Finally, plant samples were transferred to The Plant Biocentre at NTNU, Trondheim, Norway, for hydrodistillation and gas chromatography-mass spectrometry (GC-MS) analyses of the EOs. Peppermint oil yield increased from early to full bloom and late bloom (average of all years and drying methods except for 50 and 70 °C: 2.95, 4.13 and 4.20 L/daa, respectively) as an effect of biomass production and leaf growth. The flavor-impact compounds, menthol and menthone, reached their optimum at full bloom (43-54 and 12-30%, respectively). Prewilting led to slight decreased EO levels after 1 day (7.7%) and 5 days of ground drying (1.5%) and no EO quality changes, compared to direct drying at 30 °C. The plant weight (H2O content) was drastically decreased to the average under 80 and 45% in all years, thus reducing the energy supply and costs for the necessary final drying step.
Forfattere
Leontine Colon David E L Cooke Jens G Hansen Poul Lassen Didier Andrivon Arne Hermansen Ewa Zimnoch-Guzowska Alison LeesSammendrag
The pan-European Concerted Action on late blight `Eucablight" was set up and launched in 2003, with the aim of providing tools for investigating variation in both the host and the pathogen. Objectives include the construction of a database, (www.Eucablight.org) containing information on past and current potato cultivars and late blight populations available in the participating countries, and the design, testing and recommendation of protocols for testing host resistance and pathogen diversity. The database is structured, and made accessible, in such a way that many different target groups can use the data for their own purpose. Farmers will be able to find out about the characteristics of the pathogen and the best performing cultivars in their region. DSS advisers will be able to access the model parameters they need to build locally adapted forecasting systems and scientists will be able to employ the data to study host and pathogen interactions, and to place this in an historical perspective. Once the database is operational, maintenance and the entry of new data should take minimal effort. Submission of data is open to anybody who wants to contribute and who follows the standard protocols. We intend the database to generate enough interest to be kept up to date by members of the research community who will continue to submit their results. If this can be achieved, the database will be an important instrument for potato breeders, scientists, advisors and policy makers to follow the co-evolution of host and pathogen in Europe and inform the use of appropriate resistance genes and control measures.
Forfattere
Trygve S. Aamlid Bjørn Molteberg Anne A. Steensohn Åge Susort Frank EngerSammendrag
Til sammen 43 sorter av 6 ulike grasarter ble prøvd på USGA golf greener på Landvik (Grimstad) og Apelsvoll (Toten) fra 2003 til og med 2005. Feltene ble stelt som golfgreen med klipping til 4.5 mm for rødsvingel og 3 mm for kvein og tunrapp, daglig slitasje, gjødsling annenhver uke, vertikalskjæring, topdressing m.m. Feltene ble bedømt for helhetsinntrykk annenhver uke og ellers for dekningsprosent, skuddtetthet, farge, sjukdom og høydetilvekst en gang pr måned. Forsøka viste at følgede sorter kan anbefales på golfgreener i Skandinavia (i prioritert rekkefølge innafor hver art): Nordlige, kontinentale områder: Hundekvein "Avalon" og "CIS AC1"; krypkvein "Nordlys", "Penncross", "Bueno", "Penn G1" og "Independence"; engkvein "Jorvik", "Leirin", "KvAt 96" og "Nor" ; rødsvingel med korte utløpere "Baroyal" og "Cezanne"; rødsvingel uten utløpere "Kiruna", "Darwin", "Soberana", "Bargreen", "Center" og "Barbirdie". Sørlige, kystnære områder: Hundekvein "Greenwich", "CIS AC1" og "Avalon", krypkvein "Independence", "Penn G1", "Nordlys", "Penn A1" og "Penn G6" ; engkvein "Jorvik", "Barking", "Denso" og "Bardot"; rødsvingel med korte utløpere "Cezanne" og "Barcrown"; rødsvingel uten utløpere "Calliope", "Center", "Barbirdie", "Kiruna", "Rossignol" og "Bargreen". tunrapp "TruePutt" kan ikke anbefales i noe område av Skandinavia.