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
Abstract
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.
– Fertilization experiments on forest mineral soils: A review of the Norwegian results
Petter Nilsen
Authors
Petter NilsenAbstract
The paper gives a brief overview of the background, history and main results of forest fertilization experiments on mineral soils in Norway. Positive results of initial phosphorus (P) fertilization on survival and growth of Norway and Sitka spruce have only been achieved in the coastal districts of western Norway. Other elements have seldom given any significant effect.In young and old stands of Norway spruce and Scots pine nitrogen (N) fertilization with 150 kg N ha-1 usually gave increment increases in the range of 1-2 m3 ha-1 yr-1, for a period of 6-8 yrs after application. Given individually, no other element has proved stimulating to stem growth in a similar way. In young Norway spruce stands P has often given additional growth response when given together with N. Liming has been shown to have no or negative effects on tree growth. Fertilization experiments have changed from being management orientated towards addressing the problems of possible nutrient imbalances.
Authors
Halvor TorgersenAbstract
No abstract has been registered
Authors
Oddvar SkreAbstract
Småplanter av tre bjørkepopulasjonar (Betula pubescens) blei dyrka i veksttorv ved to ulike gjødselnivå, tilsvarande 1 og 10 g N m-2 yr-1 ved 50 og 450 m høgd i det sørlege Noreg. Det var ei sterk opphoping av karbohydrat i røter frå det høgaste feltet, samanlikna med det lågaste. Normal og alternativ (cyanid-resistent) respirasjon blei målt i stengel- og rotsegment og på avskorne bladskiver frå dei tre bjørkepopulasjonane. Den totale og alternative mørkerespirasjonen minka med aukande temperatur i bladskiver og stengelsegment. I rotsegment frå dei same plantene auka derimot totalrespirasjonen med temperaturen. Ved lågt gjødselnivå var det ein viss reduksjon av respirasjonen i skot ved høg temperatur, og det meste av denne var cyanid-resistent, i.e. ikkje kopla til veksten. Den økologiske tydinga av dette er at ved låg temperatur kan auka alternativ respirasjon i blad og stengel føra til redusert vekst. Ved høg temperatur derimot, tyder auka totalrespirasjon i røter på auka absorbsjon av nitrogen i røter, som igjen fører til auka fotosyntesekapasitet, som kan kompensera for karbohydratmangel ved sterk vekst. Den alternative respirasjonen ved lågt næringsnivå og temperatur kan vera ein mekanisme for å unngå vekst ved ugunstige forhold.