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
Forfattere
Marianne Bechmann Johannes Deelstra Per Stålnacke Hans Olav Eggestad Lillian Øygarden Annelene PengerudSammendrag
Agricultural management and losses of nitrogen (N), phosphorus (P) and suspended sediments (SS) from eight small (85-2830 ha) catchments in Norway were analysed. The catchments represent areas with different agricultural production systems, soils and climate. Results from the long-term (9-16 years) in-stream monitoring show (i) large differences in levels of losses between the catchments, (ii) large interannual variability and (iii) few time-trends in losses. These results are discussed in relation to changes in agricultural policies and the implementation of soil management practices, such as reduced autumn-ploughing, catch crops, constructed wetlands and changes in nutrient application. Overall, these data demonstrate changes in farmer behaviour driven by economic incentives in combination with active extension services stimulating environmental friendly management practices. However, despite the increased implementation of mitigation methods by farmers, improvements in water quality at the catchment scale can be attenuated. More long-term monitoring programmes are clearly required. (C) 2007 Elsevier Ltd. All rights reserved.
Forfattere
Christian Uhlig Bernhard Kratutzer Wilhelm Graiss Albin BlaschkaSammendrag
Though revegetation material and methods getting progressively standardized throughout Europe comparable little attention is paid to assess long-term effects of revegetation efforts. One obvious reason, beside others, is the in general short-time character of the majority of the research projects. Other possible reasons may include an insufficient documentation of earlier applied materials and methods and deficiencies in recording site-specific key factors. The generally individual developed evaluation methods and procedures make it often difficult, if not impossible, to compare study sites in time and space. Thus, the aim of this paper is to suggest the development of a commonly applicable evaluation scheme for the assessment of revegetation efforts. Beside the need for a detailed documentation of the original site-specific conditions and the applied materials and methods, the here proposed scheme includes a concise qualitative and quantitative assessment of a) general soil properties, b) soil erosion, c) soil erosion control mats and mulching material, e) plant growth and development and d) post management efforts.
Forfattere
David Barton Tuomi Saloranta S. J. Moe Hans Olav Eggestad S. KuikkaSammendrag
A Bayesian network approach is used to conduct decision analysis of nutrient abatement measures in the Morsa catchment, South Eastern Norway. The paper demonstrates the use of Bayesian networks as a meta-modelling tool in integrated river basin management (IRBM) for structuring and combining the probabilistic information available in existing cost-effectiveness studies, eutrophication models and data, non-market valuation studies and expert opinion. The Bayesian belief network is used to evaluate eutrophication mitigation costs relative to benefits, as part of the economic analysis under the EU Water Framework Directive (WFD). Pros and cons of Bayesian networks as reported in the literature are reviewed in light of the results from our Morsa catchment model. The reported advantages of Bayesian networks in promoting integrated, inter-disciplinary evaluation of uncertainty in IRBM, as well as the apparent advantages for risk communication with stakeholders, are offset in our case by the cost of obtaining reliable probabilistic data and meta-model validation procedures. (C) 2008 Elsevier B.V. All rights reserved.
Forfattere
Ingrid Holtsmark Dimitris Mantzilas Vincent Eijsink May Bente BrurbergSammendrag
The Gram-positive plant pathogen Clavibacter michiganensis subsp. sepedonicus is the causal agent of potato ring rot, a wide-spread disease that causes huge economical losses. One strategy that may aid in gaining control of the disease is the development of agents that specificially inhibit growth of the pathogen. In this work, narrow-spectered antimicrobial substances that are secreted by the closely related tomato pathogen, Clavibacter michiganensis subsp. michiganensis, have been purified and studied. These antimicrobials exert growth inhibitory activity against Clavibacter michiganensis subsp. sepedonicus, and may become useful as control agents in the battle against the potato pathogen. The antimicrobial substances include a 14 kDa bacteriocin, a 2145 Da type B lantibiotic, and a series of non-proteinaceous antibiotics with molecular masses around 800-900 Da, putatively belonging to the tunicamycin family. The lantibiotic peptide, michiganin A, resembles actagardine, which is a type B lantibiotic produced by the actinomycete Actinoplanes liguriae. Both these peptides share traits with mersacidin, a well-known type B lantibiotic, including a conserved residue that is thought to be important for the antimicrobial activity of mersacidin.
Forfattere
Arne Stensvand Heidi Udnes Aamot Gunn Mari Strømeng Venche Talgø Abdelhameed Elameen Jorunn Børve Sonja KlemsdalSammendrag
The ascigerous stage (formation of perithecia with viable ascospores) of Colletotrichum acutatum was recently reported to occur on fruits of highbush blueberry (Vaccinium corymbosum) in Norway. When 113 isolates of C. acutatum from various plant species were cultured on strawberry leaf agar, nine developed perithecia with viable ascospores. Four isolates originated from apple (Malus domestica) and one each from sweet cherry (Prunus avium), raspberry (Rubus idaeus), highbush blueberry (Vaccinium corymbosum), hollyberry cotoneaster (Cotoneaster bullatus), and northern dock (Rumex longifolius). Except from blueberry, we never detected the ascigerous stage on decaying fruits or any other parts of the above mentioned plant species. On potato dextrose agar, colour of the underside of the cultures forming perithecia varied from light grey-green to dark grey-green or dark brown-green. Colour of the upperside varied greatly, being dark grey-green, grey-brown, grey, and beige-pink, and only two of the isolates were beige-pink (the raspberry and blueberry isolates). Amplified fragment length polymorphism (AFLP) analysis of the isolates using six primer combinations resulted in 103 clear polymorphic bands. A dendrogram was constructed, and based on cluster analysis using genetic similarity, the isolates could be divided into several clusters. Eight of nine perithecia-forming isolates grouped together in the dendrogram, indicating genetical difference from other isolates. This was also supported by Principal Coordinate (PCO) analysis.
Forfattere
Arne StensvandSammendrag
Black spot caused by Colletotrichum acutatum is occasionally found in strawberry fields in Norway. It was detected for the first time in 1999 and found in certified production in 2002. More than half of the certified nurseries, including the elite plant station, had symptomless infections of C. acutatum in strawberry planting material the following two years. A renovation programme was carried out, and in 2005 and 2006 C. acutatum was found in only one certified nursery. However, in 2007 latent infections of C. acutatum was detected in four certified strawberry plant nurseries. As been reported before from Norway, C. acutatum is present in almost all fruit and berry species grown in the country and has also been found on many ornamentals and in weeds, but it is a quarantine organism only in strawberry. It is particularly severe in cherry and apple. We have detected the perfect stage of the fungus in highbush blueberry, and when isolating the fungus we find a high frequency of isolates forming the perfect stage in culture. When doing genetic analysis (AFLP), the Norwegian isolates from strawberry separated in two groups. One set of isolates grouped together with strawberry isolates of C. acutatum from other countries, and the other set grouped with Norwegian isolates from several hosts, with a majority of isolates from sweet- and sour cherry. The latter group had more than 90% similarity between the polymorphic bands. There was also a third, very genetically diverse group of isolates that included most of the perithecia forming isolates. Further research will reveal if isolates from the different groups may vary in their aggressiveness to strawberry and if it will be possible to distinguish between them in simple molecular tests.
Forfattere
Randi Berland Frøseth Sissel Hansen Anne Kjersti BakkenSammendrag
Heilårs grøngjødsel er ei viktig nitrogenkjelde til økologisk korn i eit omlaup utan tilgang på husdyrgjødsel. Dagens praksis med fleire gongars slått og grønmasse som vert liggjanse på stubben for å rotne medfører stor risiko for nitrogentap. Målet med forsøket var å undersøkje i kva grad N i liggjande grønmasse bidreg til byggavlinga året etter. Resultata viser 10 % lågare eller ingen forskjell i byggavling etter heilårs grøngjodsel der grønmassen vart fjerna frå feltet samanlikna med der han vart liggjande etter kvar slått. Meiravlinga på 0,4 kg N per daa tilsvarte berre 3 % av N i overjordisk plantemasse av grøngjodsla. Kor stor del av N fra grønmassen som gjekk tapt ved utvasking eller gasstap og kor stor del som vart bygd inn i organisk materiale, og dermed tilgjengeleg for seinare kulturar, vart ikkje målt.
Forfattere
Tor Håkon SivertsenSammendrag
Some ideas connected to the scope of scientific work in agronomy and agro meteorology and the scope of the scientific principle are outlined. Then the concepts of ‘sustainability" and ‘sustainable agriculture" are presented, and the content of different definitions of these concepts is discussed. Especially the idea of sustainability as conservation of important relations is discussed.Then the concept and principle of an allodial farm or free farm, connected to Norwegian law and Norwegian traditions is presented and the history of the present law is briefly outlined. Also traditions for passage of farms from one generation to the next generation in a few other European countries are mentioned. Then the concept of allodial farm is connected to the challenges of global change of Northern Europe, and the existing ideas of commercial agriculture.The following idea is discussed: "The idea of changing the focus in agricultural production from maximizing the crop yield to keeping the ecological system of the farming and the local area sound and in shape". Man is an organism like other organisms. He ought to take care of his surroundings and the other species, to take care of a totality of biological systems on the Earth. Probably no god or gods will take care of him if he does not succeed in doing this. The content of the concepts of adaptation and mitigation connected to global change is also finally mentioned.
Sammendrag
From 2002 to 06, the annual dropout rate of certified organic farmers averaged 7.3%. A project was started in 2007 to explore farmer"s reasons for opting out of certified organic production. Important factors seem to be public regulations including standards for organic farming, agronomy, economy, and farm exit. While many organic farmers with relatively small holdings have opted out, farmers with more land and larger herds tend to convert to organic agriculture. The trend towards larger-scale farms in organic than in conventional agriculture, encouraged by the design of the organic farming payments, challenges the organic principles of diversity and fairness. Means should be considered to ensure that small organic enterprises are also economically viable.
Forfattere
Jeppe Kolding Lise Haug Sigurd StefanssonSammendrag
Growth, size at maturity, gonadosomatic index (GSI), egg size, and absolute fecundity of Nile tilapia (Oreochromis niloticus) were significantly affected by oxygen levels (1.5 +/- 1.0, 2.8 +/- 1.4, and 6.0 +/- 1.8 mg center dot L-1) in a controlled experiment designed to test the hypothesis (D. Pauly. 1984. J. Cons. Int. Explor. Mer, 41: 280-284) that O-2 is the controlling factor for the transition from juvenile to adult in fish, in general, in the context of phenotypic life history plasticity and "stunting" in tilapias. Size at maturity and the estimated asymptotic size decreased with decreasing O-2 concentration, as predicted by Pauly"s hypothesis. All fish matured at the same age (18 weeks old), which is in contrast to conventional definitions of stunting. This finding challenges the suggested plasticity in age at first maturity for tilapia. The results also challenge the hypothesis that stunting is a unique recruitment mechanism, as the smaller fish in the group with low oxygen concentration produced smaller and fewer eggs than the larger fish in the group with high oxygen concentration.