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
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.
Sammendrag
In this study, forest treated with different strengths of selective cutting (2570 % of volume removed) was remeasured after twelve years in 2005. At each of the sixteen 0.2 ha plots, including four repeats of each treatment, all trees larger than dbh 2.5 cm were calipered. We investigated growth, changes in stand structure, tree age, tree damage and crown condition.The diameter distribution displayed a reverse J-curve at all plots both before and after the cuttings. Twelve years later the curve is only slightly changed. Increment cores from 300 trees were taken to analyse annual growth reactions in different diameter classes. Most trees reacted with increased growth from the second or third year after the cutting.This improved growth accelerated the following six or seven years with 20-80% increase. Both small and large trees reacted, including severely suppressed trees. The initial crown volume and crown vitality after cutting is essential for the increased growth since several years are necessary to build up a larger and better crown. The relationship between increased growth and reduced volume per hectare indicates less competition between trees regarding nutrients and light after the cutting.
Sammendrag
An analysis of runoff measurements can reveal a great deal about the hydrological character of a catchment. There are different ways to carry out such a hydrological characterization. In this paper, characterisation of the hydrological behaviour of catchments is carried out by describing the flashiness of the runoff. Flashiness in this case is meant to express the variation in runoff over short periods. A modified flashiness index has been calculated for small agricultural catchments in Estonia and Norway respectively, based on hourly recorded discharges and a comparison has been made with results obtained from a flashiness index, which is based on average daily discharge values. The comparison revealed large differences between the two index values for the Norwegian catchments, indicating large variations in discharge values over short periods or a "flashy" nature in runoff. Only small differences were found for the Estonian catchments. Large differences were found when comparing the Norwegian and Estonian catchments. Although the flashiness index does not a-priori give information about the flow processes, it might be helpful in explaining differences in nutrient and soil losses between catchments.
Sammendrag
Freezing and thawing influence the transport potential and pathways for contaminants by altering the soil physical properties. Firstly, soil frost delays or impedes infiltration of rain and meltwater, reducing the transport rate of dissolved contaminants. But at the same time, particle bound contaminants may be mobilised because the reduced infiltration capacity increases surface runoff and erosion risk. Secondly, freezing water expands and imposes mechanical stresses on the soil, which may cause aggregate breakdown and facilitate particle detachment and transport. The influence of repeated freezing and thawing on aggregate stability of different soils is poorly documented for Nordic winter conditions. The purpose of this study (Kværnø and Øygarden, subm.) was to quantify the effect of variable freeze-thaw cycles and soil moisture conditions on aggregate stability of three soils: Silt, structured clay loam (Clay A) and artificially levelled silty clay loam (Clay B). These soils are representative of two erosion prone areas in South-eastern Norway. Field moist surface soil was sieved into the fraction 1- 4 mm, and packed into cylinders. The water content of the soil was adjusted, corresponding to matric potentials of -0.75, -2 and -10 kPa. The soil cores were insulated and covered, and subjected to 0, 1, 3 or 6 freeze-thaw cycles: freezing at "15"C for 24 hours, and thawing at 9"C for 48 hours. Aggregate stability was measured in a rainfall simulator (representing rainfall) and a wet-sieving apparatus (representing surface runoff). The aggregate stability of Silt was found to be significantly lower than of Clay A and Clay B. Clay A and Clay B had similar aggregate stabilities, even if it was expected that the artificially levelled Clay B would have lower stability. Freezing and thawing decreased the aggregate stability for all three soils, but the effect was more severe on the silt soil. There was no evident effect of water content on the aggregate stability, probably due to experimental limitations. The wet-sieving apparatus resulted in less aggregate breakdown than the rainfall simulator. Rainfall impact seemed to be more detrimental than wet-sieving the more unstable the soil was, that is, after many freeze-thaw cycles, and on silt soil. The results indicate that freezing and thawing is an important factor influencing the erosion risk of the studied soils. In the future, climate change is expected to give more unstable winters with more freezing and thawing events. Combined with more precipitation as rainfall during the winter period both runoff and erosion will probably increase, possibly resulting in heavier loads of particulate bound contaminants to surface waters. The results are also helpful for improving predictions of contaminant fate and transport, as most of the existing hydrological and soil erosion prediction models do not satisfactorily describe soil processes occurring under Nordic winter conditions. This study focused on arable soils with conventional agricultural management, where plant nutrients and pesticides pose a threat to water quality. It would be useful to conduct similar experiments on soils where other organic and inorganic contaminants are of concern, e.g. on soils where sewage sludge and compost have been applied, and soils in road cuttings and on contruction sites. References Kværnø, S.H. & Øygarden, L. submitted: The influence of freeze-thaw cycles and soil moisture on aggregate stability of three soils in Norway.
Sammendrag
The aim of this study was to compare two methods for non-destructive strength testing of wood by the use of dynamic modulus of elasticity (MOEdyn). The two methods are based on resonant vibration excitation and ultrasonic pulse excitation. Sound Pinus sylvestris L. sapwood samples treated with two copper-containing wood preservatives and two chitosan solutions were evaluated at two moisture levels. There was a significant correlation between the measurements given by the two MOEdyn test devices. An analysis of variance showed significant differences between the different treatments and between different moisture levels. Potential use of the non-destructive MOEdyn methods in durability testing is discussed.
Forfattere
Trygve S. AamlidSammendrag
Ved etablering av økologisk engsvingelfrøeng bør vi så gjenlegget samtidig med / like etter dekkveksten og heller kutte ut ugrasharvinga. I middel for to forsøk i 2004/05 gav ni dagers utsettelse av såinga på grunn av blindharving henholdsvis 15, 20, 13 og 5% reduksjon i første års frøavling ved gjenlegg i bygg, vårhvete, grønnfôr av bygg/erter og erter til modning. Ugrasharving førte til mer kvitkløver i engåret, og gav heller ikke større dekkvekstavling i gjenleggsåret. Ved etablering av frøeng er det alltid viktig at dekkveksten ikke får for stort forsprang på gjenleggsplantene. Gjenlegg i grønnfor av korn og erter gav i disse forsøka gjennomgående større førsteårs frøavling enn gjenlegg i erter til modning, som igjen gav større frøavling enn gjenlegg i bygg eller vårhvete til modning. Det kunne imidlertid ikke påvises bedre nitrogentilgang til gjenleggsplantene etter gjenlegg i grønnfor og erter enn etter gjenlegg i bygg eller hvete. Unasett hvliken dekkvekst som velges er det derfoir viktig å høstgjødsle gjenlegget like etter at dekkveksten er høsta.
Forfattere
Dag RøenSammendrag
Gerlinde", "Rubinola" og Graminor-seleksjonen NA 46-49 var dei mest lovande av i alt 17 sortar og seleksjonar av eple i eit førsteprøvingsfelt avslutta 2004. Dei to skurvresistente (Vf) sortane "Gerlinde" og "Rubinola" er interessante, kanskje først og fremst med tanke på økologisk dyrking. "Rubinola" har mindre syrleg smak enn "Gerlinde", men "Gerlinde" har i denne prøvinga halde kvaliteten betre gjennom lagring enn "Rubinola". Vi treng meir erfaring med om desse to sortane gir årviss kvalitet før vi evt. vil tilrå nokon av dei for dyrking hos oss. NA 46-49 er eit fast, storfrukta, grøngult eple i same sesong som "Discovery". Andre sortar som var med i prøvinga var "Ahra", "Ahrista", "Vanda", "Zesta", "Bente", "Susanna", "Søta-Kari", "John-Georg" og nokre andre nummersortar (frå Sverige og Graminor).
Forfattere
Grete Waaseth Svein Grimstad Roar MoeSammendrag
The transition to flowering in the herbaceous ornamental perennial Salvia x superba Stapf `Blaukönigin" is promoted by increasing the photosynthetic photon flux (PPF), in addition to a facultative response to both vernalization and long photoperiods. Floral evocation occurred at an earlier developmental stage in unvernalized S. superba in response to increasing the PPF from 50 to 200 mmol m-2 s-1 irrespective of photoperiod, although the response was more prominent in 20-hour days compared with short days of 10 hours. After a saturating vernalization treatment, the response to PPF was bypassed when plants were grown in long photoperiods. The promotion of flowering by increasing light quantity seems to be dependent on the ambient light level during the actual evocation process irrespective of the light level received during previous vegetative growth. Further investigations are needed to uncover the response mechanism behind this PPF dependent flowering pathway.
Sammendrag
Vestfold er landets nest minste fylke, men har størst andel jordbruksareal i drift i forhold til totalarealet. Ved jordsmonnklassifi kasjon samles jordsmonnet i grupper eller enheter basert på forskjeller og likheter. Jordsmonn som tilhører samme gruppe eller enhet, vil derfor ha en rekke felles egenskaper. Klassifi kasjonen av jordsmonnet på dyrka mark i Vestfold er basert på World Reference Base for Soil Resources (WRB). Det er en tydelig sammenheng mellom klassifi kasjon, geologisk opphavsmateriale og terrengforhold. Dette har gitt grunnlag for å dele fylket inn i 4 jordsmonnregioner med hver sin unike fordeling av jordsmonn. 3/4 av jordbruksarealet utgjøres av WRB-gruppene Albeluvisols, Stagnosols og Cambisols, mens den siste fjerdedelen utgjøres av hele 9 andre grupper. Utbredelsen av de ulike WRB-gruppene framgår av oversiktskart i målestokk 1:400 000, samt regionvise kart i målestokk 1:50 000.
Forfattere
Petter Snilsberg Ketil Haarstad Jens Køhler Anders YriSammendrag
Bioforsk Jord og miljø har utarbeidet detaljplan for behandling av sigevann fra Paddetjern deponi i et naturbasert renseanlegg. Bioforsk Jord og miljø søker på vegne av Ski kommune teknisk etat, om etablering av renseanlegg for sigevann fra Paddetjern deponi, Siggerud. Nedbørfeltet er på 92 da hvorav 20 da er deponiareal og ca 40 da drenerer via en myr nord for deponiet. Dimensjonerende vannmengde er i gjennomsnitt på 5 m3/time. Dimensjonerende renseareal for denne typen anlegg bør være på minimum en ukes oppholdstid. Arealet som er prosjektert gir ca 12 dagers oppholdstid i gjennomsnitt. Anlegget består av et sedimentasjonsbasseng (800 m2, 2 meters dyp) med styrt strømning, ettterfulgt av et grunnere basseng (650 m2, 1 meters dyp) med torvfilter og tilplanting. Hvis overvåkningen krever at renseevnen optimaliseres kan lufting ettermonteres i innløpsdelen av sedimentasjonsbassenget, flere filterløsninger monteres i bassenget og / eller etterpolering anlegges i lokalt myrområde nedstrøms renseanlegget.