Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2017
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Authors
K.A.G Nielsen Ingerd Skow Hofgaard Shiori Koga H.U. Aamot Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Anne Kjersti UhlenAbstract
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Picea abies seedlings were given three different fertilization treatments in the nutrient solution by varying the potassium:nitrogen (K:N) ratios (2.5, 3.0 or 3.9 g g–1). All fertilization treatments were combined with short-day (SD) treatment or no such treatment (control). Above- and belowground growth responses in the seedlings were analyzed. The SD treatment resulted in significantly reduced shoot height, compared to untreated control, irrespective of K:N ratio. No combination of photoperiod treatment or fertilization treatment affected the root collar diameter. In the current year root fraction with diameter < 0.5 mm, the highest K:N ratio led to significantly increased root length in control plants. In each 0.1 mm root diameter class up to 0.5 mm, the highest K:N ratio significantly stimulated root growth in control plants, while the effect was less evident for SD plants. SD treatment stimulated length growth in some fine root diameter classes. We conclude that SD treatment is a good and sufficient measure to reduce height growth without compromising fine root growth of P. abies seedlings. Fertilization treatment did not significantly improve aboveground growth in SD treated seedlings, and only limited effects on root growth was seen on control plants.
Abstract
BACKGROUND: It is questioned if Norwegian nurseries can compete with the continental nursery industry in an open market. OBJECTIVE: Investigated how quality of certified Norwegian strawberry transplants, developed and yielded from planting to first cropping year. METHODS: Plant qualities of Norwegian fresh and cold stored bare root- and plug-plants of ‘Korona’ and ‘Sonata’ were examined for establishing and yield parameters in the open, after three intervals of planting. Fresh plug-plants were delivered when available. Trials were established at NIBIO Research Station Kvithamar, Norway. Growth and yield parameters were registered in the establishing and cropping years. RESULTS: Plant establishment was poor in 2013 compared with 2014. Bare-root plants stored at 2–4°C generally developed poorly. Plug-plants established well at all delivery dates, except fresh plug in one year. Development of runner plants depended on plant type, cultivar and year. Plug- and bare root-plants planted immediately after first delivery generally developed best crowns. Primary flower primordia reached a more developed stage for ‘Sonata’ than for ‘Korona’. Fruit yield of bare root was low in the establishing years. Plant-types differed in yield and fruit weight between cropping years. CONCLUSIONS: Bare-root and plug- plants planted one day after delivery generally yielded best. Storage of bare-root plants generally reduced yield. Fresh plug plants had low yield when planted late. Fruit yield of A15 and A13 in the establishing year was not satisfactory.
Authors
Akagic Asima Amila Vranac Spaho Nermina Fuad Gasi Mirsad Kurtovic Mekjell MelandAbstract
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Trygve S. AamlidAbstract
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Authors
Dorothee Kolberg Lars Olav Brandsæter Göran Bergkvist Knut Asbjørn Solhaug Bo Melander Björn RingselleAbstract
Quackgrass is a problematic agricultural weed in the temperate zones of the world and is difficult to control without herbicides or intensive tillage. However, it may be possible to control quackgrass with less environmental impact by combining multiple low-intensity control methods. A pot experiment was conducted in July to October 2012 and repeated in June to September 2013 to investigate the effect of rhizome fragmentation, competition from white clover, shoot-cutting frequency, and cutting height on quackgrass. Rhizome fragmentation was expected to result in more, but weaker, quackgrass shoots that would be more vulnerable to shoot cutting and competition. However, by 20 d past planting, rhizome fragmentation did not change the total number of quackgrass shoots per pot, because an increase in main shoots was offset by a decrease in tiller numbers. Rhizome fragmentation did not reduce quackgrass biomass acquisition during the experimental period. Although rhizome fragmentation did reduce total fructan content, it did not enhance the effect of clover competition, shoot-cutting frequency, or shoot-cutting height. Clover competition by itself reduced quackgrass shoot numbers by 72%, rhizome biomass by 81%, and belowground fructan concentration by 10 percentage points, compared with no competition. The more frequently quackgrass shoots were cut, the less biomass quackgrass acquired, and a high shoot-cutting frequency (each time quackgrass reached 2 leaves) resulted in a lower belowground fructan concentration than a low shoot-cutting frequency (at 8 leaves). However, in pots without competition, a higher shoot-cutting frequency resulted in more quackgrass shoots. A lower shoot-cutting height (25 mm) had more impact when shoot cutting was more frequent. In conclusion, rhizome fragmentation did not reduce the number of quackgrass shoots or rhizome biomass, but competition from white clover, a high shoot-cutting frequency, and a low shoot-cutting height strongly suppressed quackgrass biomass and fructan acquisition.
Authors
Margarita Novoa-Garrido Celine Rebours Lise Aanensen Torfinn Torp Vibeke Lind Håvard SteinshamnAbstract
The effects of a commercial seaweed (SW) product and extracts collected from wild SWs in the Northern Norway on cultivable commensal intestinal bacterial groups isolated from Norwegian White sheep ewes were studied in vivo and in vitro. Bacterial counts from faeces from the ewes fed with supplement which contained SW meal throughout the entire indoor winter period had significantly lower lactic acid bacteria (LAB) counts (P ≈ .05). The screening of extracts from red and brown SWs showed that a number of the organic extracts had an inhibitory effect on the growth of the two Enterococcus sp. isolates. The results indicate that Ascophyllum nodosum supplementation reduces LAB counts in the ewes and the lambs, and that extracts from this SW have an inhibitory effect on the growth of Enterococcus sp. isolates.