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.
2023
Sammendrag
Landbruket er en særdeles viktig bidragsyter til norsk beredskap. Mat og innsatsfaktorer til matproduksjon utgjør våpen i geopolitiske konflikter. Matsikkerhet er derfor avgjørende for stabile og trygge samfunn, og for å forhindre konflikter. Betydningen av dette er bragt til nye høyder de siste årene gjennom krig, pandemi, klimakrise og uår. Drøvtyggerne er fermenteringseksperter som omdanner ufordøyelige beitevekster til energi og fullverdig protein for mennesker. Ressursgrunnlaget i Norge tilsier at det bør satses på disse husdyra - ikke minst i Nord-Norge. Dette er viktig for å øke norsk selvforsyning og matsikkerhet.
Forfattere
Tor J. JohansenSammendrag
Den 10. april 1923 overtok staten gården Holt på Tromsøya, og Forsøksgården Holt ble etablert. Den har seinere skiftet navn flere ganger etter ulike omorganiseringer, og har i dag navnet NIBIO Tromsø (Norsk institutt for bioøkonomi). Gården var og er verdens nordligste forskingsstasjon innen jord- og plantekultur. Den var samtidig en av de første vitenskapelige institusjonene i Tromsø, nest etter Tromsø Museum (1872) og Geofysisk Institutt/Værvarslinga for Nord-Norge (1918–20). Gården Holt ligger landlig til på vestsiden av Tromsøya, men samtidig nært bysentrum og flyplass.
Sammendrag
Det er ikke registrert sammendrag
2009
Forfattere
Marianne Vileid Uleberg Ievina Sturite Trond Maukon Henriksen Olavi Junttila Marit JørgensenSammendrag
Det er ikke registrert sammendrag
2008
Sammendrag
In order to improve the basis for utilizing white clover (Trifolium repens L) in northern agriculture, we studied the effects of defoliation intensity on spring growth in a sub-arctic climate in relation to carbohydrate and nodule status. White clover plants (cv Snowy) were studied in a pot experiment in the field on the coast of northern Norway from spring 2001 until spring 2002. The experiment was repeated with some modifications from spring 2002 until spring 2003. During the growing season from summer to autumn, the plants were totally stripped of leaves down to the stolon, cut at four or seven cm height or left undisturbed. The plants were sampled destructively in autumn, early spring and late spring and sorted into leaves, stolons and roots. The plant material was weighed and analysed for carbohydrate reserves and nodule number. Defoliation during the growing season resulted in reduced concentration of reserve carbohydrates in autumn and reduced winter survival of the stolons. The most severe defoliation treatment reduced the herbage growth in spring. In contrast, the two milder defoliation treatments had no effect on herbage growth during spring or on total plant dry matter and nodule status in late spring. In conclusion, moderate defoliation during the growing season had no effect on herbage growth the following spring nor on carbohydrate, nodule or dry matter status of the plant in late spring. Moderate defoliation increased spring growth and thereby also the nitrogen demand of the plants. This probably enhanced nodule formation and development of inactive to active nodules.
2006
Forfattere
Ievina Sturite Marianne Vileid Uleberg Marit Jørgensen Trond Henriksen Anne Kjersti Bakken Tor Arvid BrelandSammendrag
In order to improve the basis for utilising nitrogen (N) fixed by white clover (Trifolium repens L.) in northern agriculture, we studied how defoliation stress affected the N contents of major plant organs in late autumn, N losses during the winter and N accumulation in the following spring. Plants were established from stolon cuttings and transplanted to pots that were dug into the field at Apelsvoll Research Centre (60 degrees 42'N, 10 degrees 51' E) and at Holt Research Centre (69 degrees 40' N, 18 degrees 56' E) in spring 2001 and 2002. During the first growing season, the plants were totally stripped of leaves down to the stolon basis, cut at 4 cm height or left undisturbed. The plants were sampled destructively in late autumn, early spring the second year and after 6 weeks of new spring growth. The plant material was sorted into leaves, stolons and roots. Defoliation regime did not influence the total amount of leaf N harvested during and at the end of the first growing season. However, for intensively defoliated plants, the repeated leaf removal and subsequent regrowth occurred at the expense of stolon and root development and resulted in a 61-85% reduction in the total plant N present in late autumn and a 21-59% reduction in total accumulation of plant N (plant N present in autumn + previously harvested leaf N). During the winter, the net N loss from leaf tissue (N not recovered in living nor dead leaves in the spring) ranged from 57% to 74% of the N present in living leaves in the autumn, while N stored in stolons and roots was much better conserved. However, the winter loss of stolon N from severely defoliated plants (19%) was significantly larger than from leniently defoliated (12%) and non-defoliated plants (6%). Moreover, the fraction of stolon N determined as dead in the spring was 63% for severely defoliated as compared to 14% for non-defoliated plants. Accumulation in absolute terms of new leaf N during the spring was highly correlated to total plant N in early spring (R-2 = 0.86), but the growth rates relative to plant N present in early spring were not and, consequently, were similar for all treatments. The amount of inorganic N in the soil after snowmelt and the N uptake in plant root simulator probes (PRS (TM)) during the spring were small, suggesting that microbial immobilisation, leaching and gas emissions may have been important pathways for N lost from plant tissue.
2005
Sammendrag
Resultater viser at høsteregimet influerer på kvitkløverens innhold av N om høsten, tapet av N fra stoloner gjennom vinteren, og akkumulasjon av N i nye blad om våren. Resultatene antyder også at N tapt fra kvitkløveren gjennom vinteren kan være svært mobilt.
2003
Forfattere
Marianne UlebergSammendrag
Et stort problem for bruk av kvitkløver i eng og beitemark i dag er sen vårvekst. Det medfører at det blir lite kvitkløver i første slåtten og at plantene lettere utkonkurreres av gressene. Ved Nordnorsk kompetansesenter på Holt har et større feltforsøk blitt utført for å undersøke effekt av ulike driftsmåter på vinteroverlevelse og vårvekst hos kvitkløver. De foreløpige resultatene antyder at beite og slått ikke virker negativt på vårveksten til kvitkløver
Sammendrag
White clover (Trifolium repens L.) is a perennial legume forming nitrogen fixing symbiosis with the soil living bacteria Rhizobium leguminosarum bv. trifolii. The species is the most important pasture legume in temperate zones, despite the fact that it grows poorly at low temperatures. The poor growth at low temperatures currently restricts utilization of the species as a natural nitrogen source in northern areas. Both nitrogen fixation and growth of white clover is limited in spring, probably due to low temperatures. This drawback is particularly pronounced under northern climatic conditions where temperatures are low during most of the growing season. Better understanding of the growth and nitrogen dynamics of white clover at low temperatures is vital for successful management of white clover/grass pastures and optimisation of biological nitrogen fixation, especially at northern latitudes. In a research project with field experiments conducted under different climatic conditions, we are studying winter survival, spring growth and nitrogen dynamics of white clover in relation to its physiological condition. We are especially focusing on below ground biomass and the functioning and longevity of roots and nodules. The physiological condition of the plants is manipulated by the use of different defoliation regimes during the growing season. The field experiments are situated at two locations (Apelsvoll at 61°N, and Tromsø, 690N). Preliminary results will be presented.
2002
Sammendrag
In a recently started research project with field experiments conducted under different climatic conditions, winter survival, spring growth and nitrogen dynamics of white clover are studied in relation to its physiological condition. Belowground biomass and the functioning and longevity of roots and nodules are especially focused. The physiological condition of the plants is manipulated by the use of different defoliation regimes during the growing season. The field experiments are situated at two locations; at Apelsvoll at 61°N, and in Tromsø, 69°N. The results show that the defoliation regimes affected the strategy of DM allocation in the white clover plants. The more frequent defoliation regime lead to increased allocation of photosynthates to leaves at the expense of roots and stolons. The defoliation regimes thus created a gradient in physiological condition of the plants