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.
2009
Authors
Sjur Baardsen Gudbrand Lien Ståle StørdalAbstract
The objective of tills article wits to explore how marginalization of revenues front timber sales relative to income from agriculture and employment affects profit efficiency (the ratio of actual profit to maximum obtainable profit). We also sought to identify and measure the effects of other relevant inefficiency factors. A translog profit. frontier function with all inefficiency module was estimated using a panel of 2.265 observations of 385 active Norwegian forest. owners for 1991-2004. We found that profit efficiency decreases as the revenues from timber sales fall relative to agricultural or wage income. Other factors decreasing the efficiency were logging distance (beyond what can be explained by logging costs), fragmentation of the forest property, and time. Factors increasing profit efficiency were experience (age). information (possession of a management. plan). and geographical location (centrality). Oil the basis of our results we make recommendations oil how forest owners can improve their profit. efficiency. We also suggest further developing and streamlining contract regimens as policy instruments for promoting efficiency. FOR. SCI. 55(6).524-532.
Abstract
The vine weevil, Othiorynchus sulcatus, is a serious pest in strawberries and biological control methods are needed to combat this pest. Formulations of the insect pathogenic fungus Metarhizium anisopliae is registered for use against Otiorhynchus spp. in several countries but no fungal control agents are avilable for control of O. sulcatus in Norway. All developmental stages of Otiorhynchus spp. are susceptible to virulent insect pathogenic fungal species, but best control has been achieved against the larvae (Moorhouse et al. 1992). A number of studies have shown that M. anisopliae and Beauveria bassiana have good potential against Otiorhynchus spp. (Cross et al. 2001). In field grown strawberries, good control with Metarhizium has been reported when environmental conditions for the fungus are favourable (Oakley 1994). Temperatures in excess of 15oC are required for good control by most fungal isolates. Low temperature is therefore a major restricting factor for use of fungi outdoors (Gillespie et al. 1989, Soares et al. 1983). Isolates with low temperature optimums could therefore be well suited for field conditions in Northern Europe, where soil temperatures at the time when most larvae are found in the soil in autumn are 10-12oC. Norwegian M. anisopliae and B. bassiana isolates have shown promising results against O. sulcatus larvae at low temperatures in laboratory bioassays (Hjeljord & Klingen 2005). One of the Norwegian M. anisopliae isolates has also shown good competition with other soil fungi in laboratory experiments (Hjeljord & Meadow 2005). In addition to being cold tolerant, rhizosphere competence is important for fungal control agents that are used to control root feeding pests. "Rhizosphere competence" has been defined when considering biological control agents as "the ability of a microorganism, applied by seed treatment, to colonize the rhizosphere of developing roots" (Baker 1991). In this study we therefore aimed at testing the survival and rhizosphere competence of two different cold active Norwegian isolates (M. anisopliae isolate NCRI 250/02 and B. bassiana NCRI 12/96) in a semi field experiment in Norway. These were compared with the commercially avilable M. anisopliae isolate Ma43 originating from Austria (the isolate is also known to have many other names (Eilenberg 2008)). The study was conducted by estimating fungal concentrations in the bulk and rhizosphere soil surrounding the strawberry plant roots by counting colony forming unists (CFUs). The highest numbers of B. bassiana NCRI 12/96 CFUs were seen in the rhizosphere at 1.87x109 per liter soil 3 months after application. The highest numbers of M. anisopliae NCRI 250/02 CFUs were seen in the rhizosphere at 2.41x109 per liter soil 1 year after application. Numbers of CFUs for the M. ansiopliae Ma43 CFUs were generally lower than for the Norwegian isolates, but also for this isolate a higher fungal concentration was found in the rihzosphere soil than in the bulk soil.
Abstract
No abstract has been registered
Authors
Alhaji S. JengAbstract
No abstract has been registered
Authors
Christian Guido Bruckner Peter, G. KrothAbstract
No abstract has been registered
Authors
Rahel C Brändli Anders Bergsli Upal Ghosh Thomas Hartnik Gijs D. Breedveld Gerard CornelissenAbstract
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Authors
Lukas Gudmundsson Holger Lange Lena M. Tallaksen Kerstin StahlAbstract
No abstract has been registered
Abstract
The estrogenic mycotoxin zearalenone (ZON) produced by some Fusarium spp. causes reproductive problems and hyperestrogenic syndromes in mammals. In an effort to elucidate the molecular pathways of ZON production, we present a comparative real-time quantitative polymerase chain reaction expression study of seven contiguous genes in the ZON biosynthetic cluster on sterile rice and during wheat and oat infection. Under ZON production on rice, the polyketide synthase (PKS) genes PKS4 and PKS13, alcohol oxidase FG12056 gene, and transcriptional regulator FG02398 gene showed similarly upregulated patterns, whereas the nonribosomal peptide synthetase (NPS) FG02394, the K+ channel beta subunit FG12015, and the protein kinase FG02399 displayed a variant pattern. During the same time period under wheat infection when no ZON was produced, the PKS genes and the NPS were downregulated relative to rice whereas the K+ channel beta subunit gene FG12015 was markedly upregulated, suggesting that it may play a role in the infection process. This is the first expression study of ZON biosynthetic genes in planta. The results give insight into the regulation and activities of the ZON gene cluster under different experimental systems and suggest a connection between ZON and a K+ channel that could reveal a novel function for ZON in Fusarium spp.
Abstract
Yields are reported from four long-term (16 30 years) tillage trials, comparing results since 1998, under relatively wet conditions, with earlier experience. In trial 1, on clay loam, mean grain yield with spring harrowing only, has since 1998 been 87% of that obtained with autumn ploughing, whereas it was 94% for the whole period since 1991. The inclusion of autumn harrowing increased these figures to 94 and 98%, respectively. Over the last six years, spring ploughing gave 5% lower yield than did autumn ploughing. Relative yields of unploughed versus ploughed treatments were negatively correlated with summer rainfall. Grain protein was lowest with spring harrowing only. In trial 2, on clay loam, direct drilling has since 1998, as in previous years, given around 10% lower yield than has autumn ploughing. Autumn harrowing gave 4% lower yield in winter wheat and 6% higher yield in spring oats than did autumn ploughing, whilst yields of spring turnip rape were not significantly affected by tillage. In trial 3, also on clay loam, six alternative straw treatments were compared under four unploughed tillage regimes. Relative to straw removal, retaining large residue amounts depressed yields hardly at all with autumn and spring harrowing, but by 7% with spring harrowing only and by 13% with direct drilling. Overall, direct drilling gave 18% lower yields in this trial than did autumn and spring harrowing, whilst the yield reduction with spring harrowing only was 7%. In trial 4, on silt loam, both spring harrowing only and direct drilling have since 1998 given 6% lower yield than has autumn ploughing, whereas autumn and spring harrowing has given 6% higher yield. Under drier conditions during 1991 1997, autumn ploughing gave up to 11% lower yield than did unploughed treatments. Straw retention was beneficial in the absence of ploughing during that period, but has had little effect in more recent years.
Abstract
General questions that arise while investigating hydrological extremes are whether these have distinct spatial and temporal variations and how these variations are linked to mean flow conditions. We analyze a large set of European stream flow series. Based on daily observations we derive annual series of stream flow deciles ranging from the minimum to the maximum, resulting in a set of eleven series for each station representing the year to year variability of the flow regimes....