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.
2005
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The phosphorus (P) Index, a risk assessment tool, is a simple approach used to rank the potential for P loss from agricultural fields. The P Index identifies areas where sources of P coincide with high risk of P transfer. Factors included in the P Index, developed for Pennsylvania, USA were justified in relation to Norwegian conditions and relevant changes were made. Phosphorus application rate was modified by crop P removal. Additional factors for: 1) P release by freezing of plant residues, 2) flooding frequency, 3) risk of leaching, and 4) annual precipitation were included. Management practices in the Index were adjusted to reflect the effect of time and method of P application on P loss, as well as erosion control measures relevant to agricultural management in Norway rather than Pennsylvania. Testing of the suggested P Index showed that it ranks the potential for P loss from several agricultural catchments in the south-eastern part of Norway relatively well (R2 /0.79). Continuous development of the Index to include new knowledge about processes for P loss as well as regional differences is of great importance for future use of the P Index.
Forfattere
D. Tønnesen Tor Myking Ingvald Røsberg Nicholas Clarke Brit Lisa Skjelkvåle Øyvind Kaste Thorbjørn LarssenSammendrag
Impact assessment for a proposed LNG plant has been carried out for three potential locations in northwest Russia. The impact from the plant is small, and the critical loads for terrestrial ecosystems and aquatic ecosystems will not be exceeded at any of the 3 locations.
Forfattere
Michel VerheulSammendrag
Det er ikke registrert sammendrag
Forfattere
Michel VerheulSammendrag
In order to increase the production of organic vegetables in Norway, a project was started to facilitate the transistion from conventional to organic greenhouse production. A growing system based on ecological production principles was tested at Bioforsk Vest Særheim. Results showed that a growing system with limited beds, using 75 l/m2 of an organic growth substrate and 24 l/m2 locally available cattle slurry as additional fertilizer, resulted in a yield comparable to traditional greenhouse tomato production. Fertilizing three times a week with 0,5 l/m2 cattle slurry in combination with sprinkler irrigation controlled by light integration showed to be equally effective as fertilizing using standard mineral nutrition. Results give rise to an economical production of organic greenhouse tomatoes.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn ØklandSammendrag
Ips typographus is considered the most destructive of the bark beetles in the coniferous forests of the Palaearctic region. At low population densities this species breeds in fresh windfalls or dying trees of Norway spruce. At high densities, in contrast, the beetles may show tree-killing outbreaks at regional scales. Spatio-temporal analyses based on pheromone trap data indicated that large windfall events may be a major instigator and synchronizer of beetle outbreaks in areas subjected to regionalized weather systems. The general dominance of lag 1 density dependence of the time series indicated that the beetle populations are constrained by intraspecific competition for breeding substrates. The time series sequence before the large windfelling of 1987 was however declining without significant density dependence. We suggest this to be a transition period, reflecting a drop in carrying capacity due to depletion of susceptible trees during the preceding outbreak period (1970s) and a drop in beetle number to below the density required to kill trees. A variety of organisms exhibit episodes of explosive population growth, triggered by disturbance events. A new general model is constructed to capture the coupling of disturbance events with resource accumulation / depletion. The model is refined and parameterized using the dynamics of the Ips typographus in Scandinavia as a model system. The waiting times between outbreaks of simulated time series were generally longer and more variable than the outbreak lengths, which agree well with the historical records in the last 250 years. Spectral analysis and logspline density plots of waiting times suggest that the transition from aperiodic to periodic population dynamics should be regarded as a continuum.
Forfattere
Jon Pickup Ricardo Holgado Hervé Marzin Leendert Molendijk Witold Karnkowski Loes den Nijs Didier Mugniery Björn Niere Joachim Müller Gerhard LauensteinSammendrag
During the last meeting on the proposal for a new council directive on control of potato cyst nematodes (PCN) in Brussels on June 2-3, 2004, it became evident that the tests to assess resistance and partial resistance in potato to PCN and interpretation of test results differ widely in the different countries and earlier recommendations (EPPO recommendation 92/3784) were not commonly adopted in the EU. Therefore the EU commission suggested that an expert working group should review the definition of resistance of potato to PCN and outline the procedures for an appropriate test to assess resistance of potato to PCN.
Sammendrag
Hydraulics of subsurface flow filters (SSF) was studied by measurement of soil hydraulic conductivity (K) variation and performing tracer tests in two SSF filters consisting of 1-4 mm Ca rich sand (shell sand). Soil samples were carefully taken at several locations in Filter I. A tracer experiment was conducted in the undisturbed Filter II using KI. The measured K variability in Filter I was used to analyze the variations in tracer breakthrough. The spatial distribution of K was obtained by fitting a variogram to observed data and interpolation using Kriging. The tracer residence probability density function (PDF) was determined by modelling the tracer movement with a 3-D groundwater model. The observed and simulated tracer arrival was compared for cases with constant K, constant K and dispersion (D), and for spatially variable K and dispersion. The results show that groundwater models were well suited to simulate solute movement in the SSF system studied. An almost perfect fit to observed tracer PDF was obtained when variable K and dispersion was included in the model. This indicates that information on K variability and dispersion is important for studying solute movement in SSF constructed wetlands.
Forfattere
Anne Falk Øgaard Tore KrogstadSammendrag
To avoid over-fertilization of potassium (K) and thereby a mineral composition in the grass crop not optimal for animal health, estimation of K release from soil is important. The analytical methods should therefore predict the total K release from soil. Furthermore, to minimize costs for the farmers they should provide information which remains valid over a period of several years. The relationship between different soil extraction procedures for K and K uptake in ley for three subsequent years after soil sampling was studied in 19 field experiments on a range of mineral soil types in Norway. Potassium determined with solutions that extracted exchangeable K or parts of exchangeable K (0.01 M CaCl2, 0.5 M NaHCO3, 1 M NH4oAc or ammonium acetate lactate) was significantly (p