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
Sammendrag
In a preliminary experiment terminal stem cuttings (4 – 5 cm) were collected in the spring (May) from a wild population of lingonberry near Holt Research Center, Tromsø, Norway. The cuttings were rooted in peat mixed with 30% perlite with and without auxin treatment (Seradix 1 or Seradix 2: 3-indol-butyric-acid). The effect of dipping in a fungicide (Rovral) was also tested. With the best treatment, control without auxin and fungicide, as much as 66% of the cuttings rooted. Both dipping in Seradix and in the fungicide reduced rooting of the cuttings. To test the seasonal variations in rooting of lingonberry cuttings, terminal cuttings were harvested regularly every month in more than one year. The results indicate that a relatively short cold period is needed to induce bud break and shoot growth. Cuttings harvested during spring and summer rooted poorly compared to cuttings harvested in late autumn and during winter. The best rooting was obtained using cuttings harvested in September and November.
Sammendrag
Det finst fleire arter blåbær som kan dyrkast, men i Noreg er Vaccinium myrtillus dominerande. I Kanada har dei utvikla dyrkingsteknikken for blåbær dei siste 50 åra, og i dag er det ein stor blåbærproduksjon der. Bæra vert husta både mekanisk og med enklare utstyr, men både ugras og utttørking er betydelege utfordringar.
Forfattere
Inger MartinussenSammendrag
Det er ikke registrert sammendrag
Sammendrag
The ability of perennial grasses to maintain frost hardiness throughout the winter, and to resist dehardening during periods of mild weather is crucial for winter survival in the northern region. We tested the effects of dehardening conditions on two contrasting varieties of timothy and two of perennial ryegrass. The plants were grown in pots placed close together in the field to simulate sward conditions. Dehardening treatments started in January and April when bags with plants were brought from the field into a phytotron and treated with 3o, 9o and 15oC, 12 h light. The degree of dehardening was measured as loss of frost tolerance (LT50) after the plants were exposed to the dehardening conditions for 0, 2, and 6 and 9 days. Perennial ryegrass was less frost hardy than timothy, and in April the ryegrass plants were in bad shape and had lost almost all hardiness. The `Engmo" timothy had an initial higher degree of frost hardiness than `Grindstad" timothy both in January and April. However, `Engmo lost frost hardiness at the same rate or quicker than `Grindstad" when exposed to 9o and 15oC both in January and April. It however maintained almost all hardiness at 3oC, whereas Grindstad also at this temperature dehardened substantially. The study did not confirm the hypothesis that the more winter hardy cultivars deharden more slowly than the less frost tolerant cultivars. However, further studies need to be conducted to investigate in more detail whether there is a differing cardinal temperature for dehardening between cultivars.
Sammendrag
The growth and development of frost tolerance (LT50) of four cultivars of timothy and four of perennial ryegrass was followed from autumn to spring at Holt (69º N) and Særheim (58º N). The plants were grown in pots placed close together in the field to simulate sward conditions. Most cultivars achieved a higher level of frost hardiness at Særheim than at Holt. The exception is `Engmo" timothy that achieved similar frost tolerance at both locations, and `Riikka" perennial ryegrass that reached higher frost tolerance at Holt. At Holt, all cultivars of both species showed their maximum frost tolerance in January. At Særheim, all ryegrass cultivars showed their highest frost tolerance in January, whereas all timothy cultivars showed their maximum in March. Substantial dehardening occurred from January onwards at Holt, and from March onwards at Særheim. Partial ice encasement in the pots at Holt can probably explain, to a large degree, the rapid loss of frost tolerance from January to March. There was a much larger loss of tillers during winter at Holt compared to Særheim, and in perennial ryegrass compared to timothy. The data will be used in the development of a simulation model for grass overwintering. A major challenge in the modelling seem to be the interaction between ice encasement and frost hardiness: on one hand, frost hardiness and ice encasement tolerance are often positively correlated; on the other hand, ice encasement can severely reduce frost hardiness.
Forfattere
Marit JørgensenSammendrag
In this study four Norwegian white clover cultivars were compared with the Danish variety Milkanova under farm site conditions in the different climatic conditions of Norway. A series of field experiments were established with five different white clover cultivars sown in grass mixtures. The swards were defoliated at a sward height of 20 cm to simulate grazing. There were no clear differences in yield production or clover content between the cultivars in the southerly/lowland regions when averaged over three years. Milkanova is a relatively high yielding variety, but has a poor overwintering capacity. The grass/clover mixtures containing Milkanova had the highest yield in the first years of the experiment, but the yields declined and tended to be lower than other cultivars in the third year, with significantly lower clover content. In the alpine/northerly regions, grass/clover mixtures containing Milkanova had lower yield, and lower clover content from the start of the experiment. Both protein, ash and NDF contents were closely linked with white clover content in the swards; with more protein and ash less NDF in plots containing more clover. Feed quality was lower in 3rd cut than in 1st cut.
Sammendrag
To sortar av timotei og fleirårig raigras med ulik veksttid fram til herding, vart undersøkt m.o.t. evne til rotvekst gjennom vinter (3 uttak) og vår (1 uttak). Planter vart utsette for moderat froststress ved kvart forsøksuttak. Resultata viste at for timoteisortane hadde den nordlege sorten Engmo større rotvekst om våren enn den meir sørlege sorten Grindstad. Forsøket viste at timotei og raigras hadde ulik rotregenereringsevne i same forsøksperiode. Om våren viste alle sortane større rotvekst etter sein såing året før.
Sammendrag
Temporal changes in the scores of selected soil fertility indices were studied over six years in three different cases of organic crop rotation located in southern, eastern and central Norway. The cropping history and the initial scores of fertility indices prior to conversion to organic cropping differed between the sites. Crop yields, regarded as an overall, integrating fertility indicator, were in all rotations highly variable with few consistent temporal trends following the first year after conversion. On the site in eastern Norway, where conversion followed several years of all-arable crop rotations, earthworm number and biomass and soil physical properties improved, whereas the system was apparently degrading with regard to P and K trade balances and contents in soil. On the other two sites, the picture was less clear. On the southern site, which had a relatively fertile soil before conversion, the contents of soil organic matter and K decreased during the six-year period, but the scores of other fertility indices showed no trends. On the site in central Norway, there were positive trends for earthworm-related indices such as worm biomass and tubular biopores, and negative trends for soil porosity. The results, especially those from the eastern site, illustrate the general difficulty in drawing conclusions about overall fertility or sustainability when partial indicators show divergent trends. Consequently, the study gave no unambiguous support to the initial working hypothesis that organic farming increases inherent overall soil fertility, but rather showed that the effect varied among indicators and depended on status of the cases at conversion. It is concluded that indicators are probably better used as tools to learn about and improve system components than as absolute measures of sustainability.
Forfattere
Vibeke LindSammendrag
Et fireårig prosjekt med fôring av økologisk søyer i tiden rundt lamming ble gjennomført ved Planteforsk Tjøtta fagsenter i 2002 til 2005. Søyer ble tildelt grovfôr etter appetitt og økologisk kraftfôr eller potet (2002/2003), krossa korn (2004/2005) og fiskespon. Målet var å undersøke produksjonsresultatene hos søyer og lam ved bruk av ulike kraftfôrslag.
Forfattere
Vibeke LindSammendrag
Det er ikke registrert sammendrag