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.
2001
Authors
Mekjell MelandAbstract
An intensive field planting of `Edda", "Opal" and "Mallard" plum trees (Prunus domestica L.) all grafted on the semidwarf rootstock St. Julien A was established in 1993 at Ullensvang Research Centre, western Norway at 60 ° North. The objectives were to evaluate four different single row planting systems (vertical axis, free spindle, hedgerow and Y-trellis) and three planting densities ( 0.5, 1.0, 1.5 x 4 m for the Y-trellis and hedge trees and 2.0 x 4 m for the central leader trees) in a northern climate. These planting distances give a range of tree density of 1250 - 5000 trees per ha. The experiment gave a small yield in the third leaf on all canopy systems. During the first four cropping years, the yields/ha were positively correlated with tree density. Cumulative yield per hectare was highest on the Y-trellis and hedge trees with the highest density (5000 trees per ha). In the fourth leaf, the Y-trellis trees gave 15 tons per hectare. No differences in fruit size or the soluble solids content among canopies or densities were found.
Authors
I Szot Mekjell MelandAbstract
The cherry cultivars "Van", "Ulster" and "Burlat" grafted on the rootstocks seedling, `Colt" and `Gisela 5" were evaluated for important fruit quality parameters at Ullensvang Research Centre during the 1998 season. The largest fruit size was found on the cultivar/rootstock combinations `Van"/seedling, `Ulster/Colt" and `Burlat/Gisela 5". Other parameters like fruit firmness, stone weight, soluble solids, titratable acids and pH of the fruit juice were registered as well.
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No abstract has been registered
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No abstract has been registered
Authors
Gudbrand Lien J.B. HardakerAbstract
This paper addresses the impacts of degree of risk aversion, subsidy scheme and choice of utility function on optimal farm plans in Norwegian agriculture. Data from a farm business survey (1991-1997) are combined with subjective judgements to formulate a two-stage utility-efficient programming model. Under existing policy and market conditions, the ex ante expectation was that farmers' risk attitudes are unlikely to have a large effect on choice of enterprise mix. The results tend to confirm this view, and a farmer who is hardly risk averse at all would choose the same farm plan as a very risk averse farmer. Factors such as subsidy schemes, market conditions for the products and available labour on the farm are found to be more important determinants of the optimal plans than farmers' risk attitude or the form of the utility function.
Authors
Tor MykingAbstract
No abstract has been registered
Authors
Maria Sørensen Arild Ernstsen Leidulf Lund Jarle Nilsen Anders Lönneborg Øystein JohnsenAbstract
No abstract has been registered
Authors
Carl Gunnar Fossdal Nina Elisabeth Nagy Praveen Sharma Anders LönneborgAbstract
Here we describe the detection, developmental accumulation and cellular location of the putative plant defensin SPI1 (spruce pathogen induced 1), in the gymnosperm Norway spruce [Picea abies (L.) Karst.], using specific antibodies. Contrary to what has been found in angiosperms, it was not detected in the embryo or other parts of the seed, but accumulated during root development. The protein was detected by immunolocalization along the cell membrane of cells forming the root cortex. Furthermore, a significant accumulation of the SPI1 protein was detected in roots during the first day of infection with the fungal pathogen Heterobasidium annosum, but not in response to the pathogens Pythium dimorphum or Ceratocystis polonica
Authors
Tove M. ØstensvikAbstract
No abstract has been registered
Abstract
Materials and Methods: In the field, fresh samples were obtained from different sources. Lake samples were collected from Lake Årungen, which is located in Ås. Stream samples were collected from Ås and Birkenes in southern Norway. All the samples were filtered in the field through 0.45 um membrane filters using syringes. Then the samples were fractionated through Bond Elut SCX cartridges connected to a portable vacuum pump, based on the method of Wickstrøm et al. (2000). A portion of the sample was passed immediately through the cation exchange cartridge. After the fieldwork another portion of the sample was taken to the laboratory where the same fractionation procedure was applied. These two fractions were then analysed for non-labile aluminium. A portion of the unfractionated sample was also analysed for total dissolved aluminium. An additional laboratory fractionation with a time lag was also applied to observe storage effects. Subsequent determination of total elements was done using ICP-AES. Transport, pretreatment and storage can also have an effect on the pH and organic matter concentration of the samples and, through this, on the equilibrium between different Al fractions. To evaluate pH differences prior to analysis, pH values were also measured in the field and in the laboratory. DOC was also determined. Differences between fractionation in the field and fractionation in the laboratory: In this study, non-labile fractions of Al were compared instead of the labile fractions of Al (which can be removed from solution on passage through cation exchange column) that are believed to have the greatest toxic effect on organisms.