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
I forbindelse med at det er kommet flere såmaskiner på markedet som arbeider etter prinsippet om kontaktgjødsling, dvs. at gjødsel og frø plasseres sammen, er dette prinsippet for tildeling av gjødsel utprøvd i forsøk over to år. Effekt av kontaktgjødsling isolert er undersøkt, og også effekten av å gjødsle med en relativt liten mengde gjødsel om våren som kontaktgjødsel i kombinasjon med breispredning av resterende gjødsel på trebladstadiet. All gjødsla gitt som radgjødsling på tradisjonell måte har vært målestokk.
Sammendrag
In Norway and Finland, strawberry cultivation in greenhouses still is limited. However, interest in strawberry cultivation in greenhouses or under high tunnels is increasing rapidly. Controlled environments offer growers an opportunity to produce strawberries year-round, and specifically, during the off-season (September to June) when Norwegian and Finnish strawberries are not readily available and carry a high price. Work on manipulation of flower induction through temperature and photoperiod fluctuations in Norway and Finland in order to develop out-of-season strawberry production are presented and discussed.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Anne Kari BergjordSammendrag
Delt gjødsling i bygg ved begynnende stråstrekking (Z 31) har i Midt-Norge gitt gode resultat både med hensyn til avlingsmengde og legde. Optimal nitrogenmengde ved delgjødsling vil variere mellom år i forhold til vær og vekstforhold. For å prøve å tilpasse nitrogenmengde gitt ved delgjødsling best mulig til plantenes behov det enkelte år, ble det i 2003 utarbeidet en anbefalingstabell med delgjødslingsråd basert på målinger med N-tester. Tanken var at jo høyere verdier en målte med N-tester like før delgjødsling, dess mindre ville en ha igjen i netto utbytte for delgjødsling. Vekstforholdene etter delgjødsling spiller imidlertid en viktig rolle for i hvilken grad plantene klarer å nyttiggjøre seg den nitrogen-mengden som tilføres. Målinger med N-tester vil derfor aldri kunne gi noe fasit-svar på optimal gjødslingsmengde, men de kan fungere som en pekepinn på plantenes nitrogenbehov ved delgjødsling.
Forfattere
Erik Dybing Tore Sanner Jan Alexander Helle Katrine Knutsen Edgar Rivedal Bjørn Næss Hilde Kruse Ingolf Nes Janneche Utne Skåre Anne-Katrine Lundebye Martinus Løvik Wenche Kristin Farstad Lene Frost Andersen Georg Kapperud Øyvind Lie Judith Narvhus Leif SundheimSammendrag
Det er ikke registrert sammendrag
Forfattere
Tore Sveistrup T.K. Haraldsen R. Langohr V. Marcelino J. Kværner Tore SveistrupSammendrag
Land use and seasonal freezing is assumed to influence the transport of water and particles through the soil. The aim of this study was to identify, measure and interpret changes in soil pedality that could influence the transport of water and particles through the soil profile. The morphological, physical and chemical properties of three soils on a plateau in the Vansemb area, south eastern Norway, were compared. The soils have 60 to 90 cm thick silty sediments deposited above a marine clay substratum. One site had always been under natural forest vegetation. The second site had been afforested with spruce for 40 years after centuries of cattle grazing without ploughing. The third site had been under cultivation for about 70 years. Because of winter freezing, the upper horizons display a platy pedality created by the growth of ice segregation blades. This is followed by a desiccation structuration with vertical shrinking fissures lining a prismatic pedality in deeper horizons. As frost penetrates deeper in soils under crop and grassland, the platy structures are deeper in these sites and overlap with the vertical fissure system. As a result of tillage operations, the horizons below the plough layer became denser. This decrease in porosity is to some degree counterbalanced by the active ice segregation and the earthworm activity. Tillage operations are also responsible for the filling of the vertical fissure system with particles from the horizons above. The shift to crop or grassland increased bioturbation, mainly by earthworm populations. This activity remained at least partly preserved, even after 40 years of afforestation. Burrowing animals were absent from the mineral horizons of the forest soil. Comparative studies, as this one, ascertain the orientation of soil evolution; and thus provide essential information for soil management with minimal degradation and particle transport.
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.
Forfattere
Anssi Niskanen Anders LunnanSammendrag
Entrepreneurship can be defined as the process of transformation of new economic opportunities into values in the markets. It has become the engine of economic and social development throughout the world. Rural areas have some fundamental disadvantages for enterprises and entrepreneurship: they provide less skilled labor, less non-traded inputs to industry and at a higher cost, and finally but perhaps most importantly, rural areas are less attractive in terms of access to knowledge and information than concentrations of industries and population.Often the actions for new entrepreneurship in rural areas are targeted to the production and use of natural resources e.g. in agriculture, fishery, forestry, processing and nature-based tourism. Rural areas also have some fundamental advantages for enterprises and entrepreneurship as they provide cheap location for the enterprises, good quality of life for the employees and reliable unskilled labor.Entrepreneurship policies can be divided into policies that support the demand or supply for entrepreneurial activities.The (i) demand side policies aim to elaborate the opportunities to engage actors in entrepreneurial activity. They include, for example, deregulation of entry in the markets, privatization of public services and promotion of firm linkages or clustering. The (ii) supply side policies focus on promoting the capabilities of individuals and firms and facilitating access to resources, for example, via education and training, incubators, micro-credits and other financial incentives and various promo-campaigns. Entrepreneurship policy can also (iii) change the risk-reward profile of an entrepreneur by shaping taxes, subsidies, labor market rules and bankruptcy regulations. The aim of this paper is to consolidate the knowledge on the applied entrepreneurship policies (i-iii) in forestry in Finland, Norway, Japan, Australia, the Philippines and the United States. Aside this, the paper aims for identifying research needs and gaps of knowledge on forest sector entrepreneurship to suggest approaches for future research.
Forfattere
Astrid Oberson Erik JonerSammendrag
Microbial uptake and immobilization of P, and its subsequent release and redistribution, play central roles in the biogeochemical cycling of P in soil. Soil microorganisms constitute a pool of mostly labile organic P compounds that are rapidly hydrolysed once the cells are disrupted. The size of this pool mainly depends on soil type, land use and the related content of soil organic matter and can, therefore, in agricultural soils be affected through organic matter management. The quantities of microbial P extractable after fumigation-extraction reported for mineral topsoils across different ecosystems and litter layers encompass a range from 1 to around 200 mg P kg-1, or between 0.5 and 26% of the total P content in the corresponding soils. Because fumigation does not release all microbial P, the total amount of microbial P can be up to several times higher. Current estimates are precise enough to detect changes in the microbial P pool as a result of changes in land use, agricultural practices or environmental factors. Refined methods are still needed to quantify P fluxes through the soil microbial biomass and to describe mechanisms and ecological interactions between microorganisms and their substrates at the physiological, biochemical and molecular level. In soils with small P contents, microbial activity does not suffer from P limitation to the same extent as plants, as soil microorganisms have highly efficient mechanisms to acquire P. Progress has been made in our understanding and quantification of organic P mineralization, and the factors determining microbial immobilization and re-mineralization sequences are better understood. Studies of P turnover using radioisotopes have revealed a highly dynamic nature of the microbial P pool even in the absence of changes in microbial P. Here, we will review recent advances in radiotracer studies of P turnover and emphasize the importance of trophic interactions, microenvironments and aspects of specific microbial life-cycles that have a major impact on turnover rates and subsequent release of microbial P in soil.
Forfattere
Einar NordhusSammendrag
Molekylær biologiske teknikker har blitt svært viktige hjelpemidler i forskjellige fagfelt innen entomologi. I en serie studier har vi brukt noen av disse teknikkene til artsidentifisering og til deteksjon og overvåkning av insektmiddelresistens i tre forskjellige insektarter. Artspesifikke primere, konstruert fra artspesifikke RAPD-PCR fragment eller fra artsunike gensekvenser, og RAPD-PCR (II) ble brukt for identifisering av de polyfage minerfluene Liriomyza bryoniae, L. huidobrensis, L. sativae og L. trifolii. Disse minerfluene er viktige skadegjørere i både felt- og veksthusmiljøer på alle kontinenter og de artsspesifikke DNA primerne vil være et godt hjelpemiddel for en rask og sikker identifisering av de karantenebelagte polyfage minerfluene. Insektmiddelresistens er et økende problem på verdensbasis. For å redusere dette problemet er det viktig å ha gode metoder for deteksjon og overvåkning. Vi har brukt en kombinasjon av molekylære, biokjemiske og bioassay-metoder for å se på resistens hos Liriomyza spp. og norske populasjoner av Myzus persicae og Bemisia tabaci. Liriomyza populasjonene ble undersøkt for "target site" resistens mot pyrethroid resistens kalt "knock down" resistens (kdr). Tre punktmutasjoner i genet for den spenningstyrte natriumkanalen, koblet til denne formen for resistens ble funnet i flere forskjellige arter og populasjoner. De norske populasjonene av M. persicae og B. tabaci ble undersøkt for resistens mot flere forskjellige klasser av insektmidler. Tre kjente resistensmekanismer ble funnet hos M. periscae populasjonene, økt esteraseproduksjon, modifisert acetylcholin esterase (MACE) og kdr. Disse tre resistensmekanismene vil øke toleransen for pyrethroid, organofosfat og carbamat insektmidler. I tillegg ble det funnet økt toleranse for imidacloprid i en M. persicae populasjon sammenlignet med en mottakelig stamme. De norske populasjonene av B. tabaci hadde alle økt toleranse for fenpropathrin, lambdacyhalothrin, chlorpyriphos og buprofezin. I tillegg var de mer tolerante for imidacloprid enn den mottakelige populasjonen. Alle de testede populasjonene, både B og Q biotypen, var mottakelig for pyriproxyfen i en bioassay. En populasjon retestet etter ca 20 generasjoner uten insektmiddelbehandling viste redusert toleranse for fenpropathrin og imidacloprid mens buprofezin resistensen var stabil.