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.
2003
Abstract
No abstract has been registered
Abstract
A model is presented to investigate the optimal economic life cycle of grass leys with winter damage problems in northern Norway and to determine the threshold of winter damage before it is profitable to reseed. A two‐level hierarchic Markov process has been constructed using the MLHMP software (the MLHMP software and the plug‐in constructed for this model are available for download at http://www.prodstyr.ihh.kvl.dk/software/mlhmp.html). The model takes uncertainty concerning yield potential, damage estimation and weather‐dependent random fluctuations into account. A Kalman filter technique is used for updating the knowledge of yield potential and damage level. The application of the model is demonstrated using data from two commercial Norwegian farms. As parameter estimates vary considerably among farms, it is concluded that decision support concerning optimal economic life cycle of grass leys should be done at farm level. The results also show the importance of using a flexible dynamic replacement strategy. Use of the model for specific farm situations is illustrated.
Authors
Guro BrodalAbstract
No abstract has been registered
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Bjørn ØklandAbstract
No abstract has been registered
Authors
M. Mandre K. Ots J. KlõseikoAbstract
No abstract has been registered
Abstract
Establishment, survival and height growth of sown and naturally regenerated Picea abies (L.) Karst. seedlings were examined in a 6 yr period in eight stands on bilberry woodland in south- east Norway. Five harvesting treatments (shelterwoods of high, medium and low density, 253/25 m patch-cut, 503/50 m clear-cut) and three scarification alternatives (unscarified, patch scarification, inverting) were combined in a split-plot design. Establishment, survival and plant height after 6 yrs were positively affected by scarification. Significant differences between patch scarification and inverting were not observed, although mortality tended to be lower, and seedlings slightly taller, after patch scarification. Establishment after natural seedfall was least successful on the clear-cut, but more or less equal at the other stand treatments. Height growth increased with decreasing overstorey retention, while there was a tendency towards lower survival on the clear-cuts and patch-cuts. Natural regeneration in the unscarified plots was unsuccessful after 6 yrs, while the different combinations of harvesting and scarification treatments usually gave sufficient regeneration.
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No abstract has been registered
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No abstract has been registered
Authors
Erik Jautris Joner C. LeyvalAbstract
Phytoremediation as a means of cleaning up polluted soils has gained popularity during the last decade due to its convenience and low costs of installation and maintenance. When the target pollutant is biodegradable, this technology exploits the stimulating effect that roots have on microbial processes and physical/chemical modifications in the rhizosphere.Among the microorganisms that affect rhizosphere processes, symbiotic fungi forming mycorrhizas induce a series of changes in plant physiology, nutrient availability and microbial composition that may determine the outcome of a phytoremediation attempt. Beyond the rhizosphere, mycorrhizal hyphae act as the roots of the roots, and may thus extend the rhizosphere into the bulk soil by creating a new interface of soil-plant interactions: the hyphosphere.We here discuss some of the recent results on phytoremediation of organic pollutants with emphasis on processes in the mycorrhizosphere, and highlight future research priorities
Authors
Fred Midtgaard Karl ThunesAbstract
Det har vært omfattende angrep i the Mountain Pine Ridge Forest Reserve, Belize, av barkbiller. Denne undersøkelsen viser at angrepene skyldes en ukjendt barbilleart med rask utviklingstid og meget rask spredning. Totalt ble 80% av reservatet angrepet før det ble stoppet. Metoder for overvåking og bekjempelse er beskrevet på engelsk og spansk. During the years from 1998 to 2002, heavy attacks by an unknown bark beetle species occurred in the Mountain Pine Ridge Forest Reserve, Belize. The species is described in this publication, and methods for monitoring and control of this, and related species, is described in English and Spanish.