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.
2008
Sammendrag
Timotei hadde større toleranse til isdekke enn flerårig raigras. Det var en sterk korrelasjon mellom isdekketoleranse og frosttoleranse, og sorter som er mer frosttolerante overlevde lengre under isdekke enn mindre froosttolerante sorter. Både frosttoleranse og isdekketoleranse økte fra november til januar, men avtok deretter i mars.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Knut Anders HovstadSammendrag
This study examines the impact of plant litter on seedling establishment in a semi-natural grassland. In a field experiment, seeds of six forbs were sown in plots subjected to either different litter quantities or addition of water extracts of litter. The response to plant litter was species specific. High quantities of litter resulted in a negative response in all species except Anthriscus sylvestris. In some of the species, the response shifted from positive or neutral at intermediate litter quantities, to negative at high litter quantities. This suggests that facilitative effects were present, although inhibitory effects dominated at high litter quantities. The physical effects were generally stronger than the chemical effects. However, water extract of litter inhibited emergence in three of the six species. Filtration using activated carbon removed the negative effect of litter extract, which suggests that the effect was caused by inhibitory compounds adsorbed by activated carbon (e.g. polyphenols) rather than by increased competition in response to nutrients added via the extract.
Sammendrag
Effects of temperature on the development and chemical composition of two cloudberries (Rubus chamaemorus L.) cultivars ("Fjellgull", "Nyby") were studied in a phytotron experiment. "Fjellgull" is a female cultivar while "Nyby" is bisexual (hermaphrodite). Pollen from a male cultivar "Apollen" or from "Nyby" was used to pollinate "Fjellgull". Selfpollination in "Nyby" was assisted by striking open flowers gently with a small brush. In addition, part of the flowers of both cultivars were treated with gibberellic acid (GA3, 10 µg dissolved in 10 µl ethanol). Plants were grown in 24-h photoperiod at constant temperatures of 18, 15, 12 and 9°C. Time from pollination to ripening increased in both cultivars with decreasing temperature from about 35 days at 18°C to about 60-65 days at 9°C. Time for fruit development was not significantly affected by GA3. Berries of "Fjellgull" were significantly larger than those of "Nyby". In both cultivars, the largest berries were found at the treatments 12 or 9°C. On the other hand, seed size was smallest at 9°C and the proportion of seed weight of total fresh weight of berry decreased with decreasing temperature. Treatment with GA3 significantly reduced the average seed size in both cultivars. Pollen type had no significant effect on the rate of development or size of berries in "Fjellgull". Ripe berries were frozen at harvest at -100°C, and tannin enriched extracts were analyzed for metabolites using liquid chromatograpy " mass spectrometric (LC-MS) techniques. In addition total phenols and total anthocyanins were analysed as described by Deighton et al. (2000). Statistical analysis and data mining were performed using a principal component analysis approach. Preliminary results indicate differences in the metabolic profiles between berries grown at low temperatures compared to berries grown at high temperatures.
Forfattere
Fykse Haldor Haldor FykseSammendrag
In stockless organic cereal systems undersowing a legume shortly after sowing of cereals is a commonly used practice. Nitrogen supply as well as retarded growth of annual weeds is mentioned as benefits of such use of legumes in cropping systems. There is, however, limited knowledge on the influence of undersown cover crops on the growth of perennial weeds. This issue was addressed in a field experiment (#1) at Ås in South-eastern Norway. Furthermore, a second series of field experiments (#2) aimed at investigating the influence of (i) time of ploughing and (ii) that of black fallow. To obtain a field (#1) with uniform distribution of the perennial weed species, root fragments of Cirsium arvense (L.) Scop. and Sonchus arvensis L. and rhizomes of Elymus repens (L.) Mould., were transplanted by hand in the spring of 2002. The experiment, designed as a split-plot with 3 replicates, was initiated in 2003 and continued until the autumn of 2006. Oat undersown with red clover versus oat alone composed each year the two main plot treatments, except in 2006, in which the whole field was seeded to oat without red clover. Each mean plot was divided into four sub-plots with mechanical treatments in autumn: 1) untreated control; 2) mowing; 3) rotary tilling and 4) shallow ploughing plus harrowing. The autumn treatments were only carried out in 2004 and 2005. The number of weeds was counted at different dates throughout the growing season, and the weed biomass was assessed just before harvest. Preliminary results showed that red clover undersown in oat, compared to oat alone, had limited and in most cases insignificant effects on biomass and number of shoots of all investigated species. No significant interaction between red clover and mechanical treatments in autumn was found. Shallow ploughing suppressed E. repens most, followed by rotary tilling, mowing and untreated, in that order. On S. arvensis, mowing showed the best control, and rotary tilling the poorest. On C. arvense, significant differences between treatments were detected only in 2005, when rotary tilling and shallow ploughing reduced the weed biomass significantly compared to the untreated control.In the second experiment series (#2) C. arvense, S. arvensis and E. repens are subjected to the following treatments: 1) black fallow (soil cultivation) + ploughing in autumn 2) ploughing in autumn 3) spring ploughing, and 4) black fallow + ploughing in spring. Preliminary results from the first experimental year have shown very clear interactions between treatment and weed species: Time of ploughing did not influence the growth of E. repens significantly. On the other hand fallow in autumn suppressed this species more efficiently than fallow in spring. In general, C. arvense and S. arvensis showed the opposite behaviour regarding both time of ploughing and effect of fallow. Spring ploughing, as well as spring fallow, suppressed these species more than treatments in autumn. However, not all comparisons were significantly different. Although the results need more attention as well as new experiments before detailed recommendations can be given, the studies indicate clearly that the effect of different treatments including time of ploughing and soil cultivation periods depends on weed species.
Forfattere
Lars Olav BrandsæterSammendrag
Det er ikke registrert sammendrag
Sammendrag
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Sammendrag
Effects of vegetation and grazing preferences on the quality of alpine dairy products.
Forfattere
Karsten Raulund-Rasmussen Inge Stupak Nicholas Clarke Ingeborg Callesen Helja-Sisko Helmisaari Erik Karltun Iveta Varnagiryte-KabasinskieneSammendrag
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