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
Anne Kristine Søvik Nina SyversenSammendrag
A lysimeter experiment with drained soil columns has been established in order to study the retention efficiency of particles and nutrients from artificial agricultural runoff in soil from a vegetative buffer zone. The effect of vegetation, grass versus trees and alder versus aspen, high and low runoff as well as different seasons has been examined. It was found that the retention of particles, total P and phosphate was significantly higher in the columns with trees compared to the columns with grass. In general this was the case for organic carbon and the nitrogen compounds as well. Columns with aspen and alder had equal retention efficiency for particles, organic matter and total phosphorus. Again this was in general valid for total nitrogen and nitrate as well. The retention efficiency for the measured parameters followed in general the pattern: particles/organic matter > phosphorus > nitrogen. The retention efficiency of the nutrients was generally better during the summer and early autumn compared to late autumn, for particles and organic carbon less difference between the seasons was observed.
Sammendrag
Because light is assumed to suppress sporulation of many downy mildews (DM), it is a common component in forecast models. We evaluated effects of light intensity and quality, temperature, and diurnal periodicity on sporulation of Bremia lactucae, the causal agent of lettuce DM. We found that suppression of sporulation by light was strongly dependent upon temperature; with little suppression by light below 10 ºC. The greatest suppression of sporulation occurred at 400-450 nm, although a lesser effect was detected at 450-550 nm. At 15 ºC, a diurnal pattern of sporulation was observed independent of light and darkness. Current forecast models for lettuce DM use sunrise and sunset to delimit the hours during which leaf wetness and high RH can induce sporulation. Our results indicate that effects of short nights and extended twilight conditions, as in Nordic countries, should be incorporated into forecast models. Also, temperature should modify model predictions of sporulation, as the suppression of sporulation by light may be greatly reduced at temperatures below 15-20 ºC. The diurnal rhythm could interact with light and temperature to confound the results of controlled environment studies, and may be the controlling factor in timing of sporulation at low temperatures.
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
Hallvard Jensen Per-Arne Amundsen J. Malcolm Elliott Thomas Bøhn Paul Eric Aspholm Paul Eric AspholmSammendrag
Prey consumption rates of piscivorous brown trout, Salmo trutta, were studied in the Pasvik watercourse, which forms the border between Norway and Russia. Estimates of food consumption in the field were similar to or slightly less than maximum values from a bioenergetic model. The piscivore diet consisted mainly of vendace, Coregonus albula, with a smaller number of whitefish, C. lavaretus. Individual brown trout had an estimated mean daily intake of approximately 1·5 vendace and 0·4 whitefish, and a rapid annual growth increment of 7-8 cm year-1. The total population of brown trout >25 cm was estimated as 8445 individuals (0·6 individuals ha-1), giving an annual consumption of 1553880 (±405360 S.E.) vendace and 439140 (±287130 S.E.) whitefish for the whole watercourse. The rapid growth in summer of brown trout >25 cm indicated a high prey consumption rate.
Forfattere
Åshild Ergon Cheng Fang Øyvind Jørgensen Trygve S. Aamlid Odd Arne RognliSammendrag
Kartleggingsfamilien "BF 14/16 x HF2/7" i engsvingel ble karakterisert for følgende frøavlsegenskaper: Krav til primærinduksjon (uker ved 6°C og 8 timer daglengde), tidlighet (skytedato), andel av skudd som danne frøstengel etter 12 ukers primærinduksjon, og antall frøstengler hos ikke-induserte planter i såingsåret (feltforsøk). "Quantitative trait loci" (QTLer) ble identifisert og sammenliknet med QTLer og gener som styrer blomsgterinduksjon i andre grasarter, herunder kornartene. En region på kromosom 1F hadde betydning for tidlighet og andel skudd som dannet frøstengel. Primærinduksjonskravet var styrt av gener på kromosom 4F, særlig i en proksimal region som korresponderer med tidlighetsgenet QTL eps6L.2 i bygg og tidlighet i flerårig raigras. Et område korresponderende til venaliseringsgenet VRN1 ble også ble påvist på kromosom 4F. Den proksimale enden av kromosom 5F hadde stor betydning for tidlighet og andel skudd som dannet frøstengel, mens kromosom 6F var med å bestemme antall frøstengler i feltforsøket. En region på kromosom 7F hadde betydning for antall frøstengler hos ikke-induserte planter i såingsåret, og dette samsvarer med regioner i flerårig raigras, bygg og ris med samme gensekvens som i modellplanten A. thaliana CO.
Forfattere
Guro BrodalSammendrag
A survey of the loose smut frequencies in certified barley seed lots in Norway during 1997"2002 showed that the disease has become more prevalent and has occurred at higher infection frequencies in recent years. Laboratory analyses (embryo method) of barley seeds harvested in 2001 and 2002, including both certified and farm saved seed, showed a large number of infected seed lots with higher than expected infection frequencies. One lot of farm saved seed (cv. Otira) from 2002 had 32% seed infection. Unexpectedly high loose smut infection frequencies recorded in fields sown with carboxin treated barley seed suggest a reduced effectiveness of the fungicide. A seed treatment experiment was conducted in 2002 using both greenhouse and field trials with two infected seed lots (cv. Otira with 14.4% and cv. Fager with 6.9% infected seeds) to evaluate and compare the effect of Fungazil C (carboxin + imazalil) and Premis Robust (triticonazol + imazalil) against loose smut. Fungazil C at normal rates reduced loose smut frequencies by approximately 50% or less. At twice the normal rate, loose smut symptoms were reduced by 60-80%. Premis Robust showed more effective loose smut control, but did not confer complete control.
Sammendrag
Environment Synthesis) family of crop models predicts cereal growth, development, and yield. CERES simulates nitrogen (N) as a yield"limiting macronutrient. Because N leaching is an economic and environmental concern, this study evaluated if CERES can be used to predict N leaching under different N management scenarios: background leaching in unfertilized corn (Zea mays L.), alfalfa (Medicago sativa L.) residue mineralization, and till versus no"till management. Data were collected during a 7"yr field experiment on tillage practices in a maize"alfalfa"maize succession. Sensitivity analyses were performed for decomposition rates of the different residue pools and the relative proportions of carbohydrate, cellulose, and lignin in the residues. During the last 5 yr, under corn, CERES accurately simulated nitrate leaching from the no"till lysimeters. Nitrate leaching was underestimated in the tillage treatments, possibly because CERES does not simulate tillage. The model is not very sensitive to the decomposition rates and to the composition of the residues
Sammendrag
In this study, we present a new method for single tree segmentation and characterization from a canopy surface model (CSM), and its corresponding point cloud, based on airborne laser scanning. The method comprises new algorithms for controlling the shape of crown segments, and for residual adjustment of the canopy surface model (CSM). We present a new criterion that measures the success of locating trees, and demonstrate how this criterion can be used for optimizing the degree of CSM smoothing. From the adjusted CSM segments, we derived tree height and crown diameter, and based on all first laser pulse measurements within the segments we derived crown-base height. The method was applied and validated in a Norway spruce dominated forest reserve having a heterogeneous structure. The number of trees automatically detected varied with social status of the trees, from 93 percent of the dominant trees to 19 percent of the suppressed trees. The RMSE values for tree height, crown diameter, and crown-base height were around 1.2 m, 1.1 m, and 3.5 m, respectively. The method overestimated crown diameter (0.8 m) and crown base height (3.0 m).
Sammendrag
Ulike metoder for å stimulere deklorering av DDT i sedimenter er undersøkt; ex-situ behandling av oppgravde masser i biopiles (hauger), in-situ behandling for strandkantmaterialer (in-situ land) og under vann (in-situ vann). Behandlingene ble optimalisert for å oppnå reduserende forhold og for å stimulere reduktiv omdanning av DDT til DDD. Under behandlingsforhold i dette prosjektet, var 30 ukers behandlingstid for kort tid til å bekrefte omdanning av DDT, kun trender ble observert. Kombinasjonen innstråling og plastdekke viste at en kan opprettholde en temperatur på 25-30°C i store deler av ranken ved lufttemperaturer rundt 10°C. Disse temperaturene er funnet gunstige for nedbryting av DDT. Også ved synkende lufttemperatur opprettholdes en temperatur høy nok til å stimulere nedbrytning. Underlag med 5 cm isopor hadde god evne til å hindre reduksjon i jordtemperaturen i nedre lag av jordmassene i ranken. Ulike tilsetningsmaterialer for å skape anaerobe forhold ble sammenlignet. Kumøkk og potetrev (biprodukt fra potetindustrien) gav størst reduksjon i oksygennivå
Sammendrag
Rapporten er en del av konsekvensutredning for Vigra Spool Base, som omhandler konsekvenser for verneområder, naturtyper/botanikk og marine områder. Vigra Spool Base er en rørsveisingsbane med dypvannskai, transportstrekning, produksjonsanlegg, rørlager og tilførselsvei. Det skal fylles ut i sjøen ved kaianlegget, mens myra skal fjernes i området for produksjonsanlegget og i traséen for rørlageret, og legges opp i voller langs anlegget. Naturreservatene Blindheimsvika og Rørvikvatnet berøres ikke direkte av tiltaksområdet. Det er ikke funnet fare for endring av de hydrologiske forholdene rundt Rørvikvatnet. Myra og underliggende løsmasser danner en naturlig uavbrutt barriere mellom tiltaket og Rørvikvatnet, og toppen av løsmassene er hard og har svært liten vannledningsevne. Rørvikvatnets vannivå er omtrent på samme høyde som tiltaket i de områdene som ligger nær vatnet. Dersom en ikke graver seg ned i løsmassene vil det ikke være fare for utlekking av vann fra Rørvikvatnet, eller endring av nedbørfeltet. Det er ikke funnet botaniske rødlistearter i området, og heller ikke sjeldne naturtyper eller endring av viktige landskapsøkologiske sammenhenger. I de marine områdene utenfor er det heller ikke funnet sjeldne arter, og tiltaket vil ikke svekke det biologiske mangfoldet marint. Tiltaket og aktiviteten på anlegget vil ha liten innvirkning på fugle- og dyreliv i området, både i verneområdene og i området ellers.