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.
2004
Forfattere
Arild SlettenSammendrag
Løkhvitråte er en karanteneskadegjører på ulike løkvekster. Den kan gi betydelig avlingstap.
Forfattere
Tor Håkon SivertsenSammendrag
In a small area of fruit production in southern Norway are placed four automated meteorological stations owned by The Norwegian Crop Research Institute. The measurements made at the stations are hourly recordings of precipitation, air temperature, leaf wetness and relative humidity of the air, plus some additional measurements of wind velocity, temperature of the soil and global radiation at two of the stations. The area has a relatively smooth topography with hills and no mountains. The highest point is located about 500 m above the sea level, and the lowest point is 16 m above sea level at the shores of the lake Norsjø, and most of the commercial orchards in the area are situated between 20 and 150 m above the sea level. The remote sensing research group at The Norwegian Meteorological Institute is providing hourly radar measurements of precipitation, from two different weather radars for this area (Gjertsen and Dahl, 2001). These measurements are collected each hour and stored in a systematic way in a database. One of the intentions of this project is to combine/compare measurements of meteorological parameters at the four automated stations with the weather radar measurements of precipitation. The precipitation data used is documented according to a system developed by The Norwegian Crop Research Institute. The representativeness of the different measurements of meteorological parameters is discussed and connected to a prediction model of apple scab infection, called modified Mills table (MacHardy and Gadoury, 1989, and Stensvand et. al, 1997) containing information on minimum air temperature and leaf wetness duration in specified periods. The original Mills table was published in 1944 ( Mills, 1944). A system for extrapolation, interpolation and combination of the relevant information mentioned is developed to get figures of temperature and leaf wetness duration to be put into the extended Mills table at all sites of this region. The usefulness of the system is to be tested and hopefully made partly operational in the growing season to come. The relevant information is communicated to the local private extension service. The intention of combining development, testing and operational use of a system is an important element of this project. References: Mills, W.D., 1944, Efficient use of sulfur dust and sprays during rain to control apple scab, Cornell Extension Bulletin, 630, 4 pp. MacHardy, W.E. & Gadoury, D.M., 1989: A revision of Mills" criteria for predicting apple scab infection periods, Phytopathology 76: 985-990 Stensvand, A, Gadoury, D.M., Amundsen, T., Semb, L., and Seem, R.C., 1997, Ascospore release and infection of apple leaves by conidia and ascospores of Ventura inaequalis at low temperatures, Phyopathology 87 : 1046-1053 Gjertsen, U. and Dahl, I., 2001, Development of a gauge adjustment method for correcting of radar precipitation estimates, Research report No. 128/2001, The Norwegian Meteorological Institute, Oslo, Norway
Forfattere
Tor Håkon SivertsenSammendrag
First the scientific method is graphically presented and interpreted in the following manner: `The test of a model is not considered merely as a test of the hypotheses, constructed mathematically, but it is also considered an explicit test of the definition of the quantitative parameters and the measuring systems of the input parameters as well". The representativeness of the input parameters to a specific model as well as the representativeness of the measured parameter values of the testing systems is considered crucial. The concept of representativeness of measured quantitative parameters is therefore outlined for further discussion and practical use in models. Furthermore the idea of differentiating the parameter definitions of the parameters of a model and the parameter definitions of a system for making measurements is presented. This notation is connected to the concept of `representativeness". The status of the system of equations of a model and the scope of such a system is discussed in the following manner: Prognostic system of equations is not interpreted as `governing" physical or biological phenomena, but `the definition of the quantitative parameters", `the system for making measurements" and the `equations" is considered a unit possible to test and use operationally. Thus the ideas of scale and representativeness are not considered separate from the system of equations.
Sammendrag
Arbeid utført hos Grimsby Gartneri for økte avlinger ved manipulering av småplanter til vinterproduksjon av jordbær.
Forfattere
K.R. RobertsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Line Hoem Erlend Ystrøm HaartveitSammendrag
Major driving forces among companies in the forest products industry are mergers and acquisitions and narrowing the strategic focus to core competencies. The combined effect is that the mutual dependency in customer-supplier relationships increases, and that the share of the total value added provided by each actor decreases. Standard techniques for process mapping are intended as the first step in process improvement. Order processes, extending from identification of demand to fulfilment of demand, commonly cross company borders. The result is an increasing need for inter-company coordination to increase efficiency of material flows. This paper presents preliminary results from the mapping of the order process between a Norwegian retail chain and its major supplier of solid wood products. A model intended for supply chain mapping has been modified and applied to this particular case. One outcome of the mapping is that a detailed overview of the process can reveal simple solutions for process improvement, as individual actors rarely focus on optimising their combined process, but rather have an internal focus. The mapping also provides a basis for evaluation of existing performance measurements, and for development of new measurements with a focus on improving the actors’ combined order process.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Svein Ole Borgen Anne Moxnes JervellSammendrag
Det er ikke registrert sammendrag
Forfattere
Akiko Satake Ottar N. Bjørnstad Sverre KobroSammendrag
We analyzed berry production in rowan, Sorbus aucuparia L., in southern Norway and examined the ramifying effects of rowan masting on the dynamics of the dominant seed predator and its parasitoid. The apple fruit moth, Argyresthia conjugella Zeller, is a pre-dispersal seed predator of rowan. The larva of the apple fruit moth rely on rowan berries, which in turn is attacked by the parasitoid wasp, Microgaster politus Marsh. We found classic masting in rowan: berry production varied across years (the mean coefficient of variation = 1.02) and was spatially synchronized at large scale (the averaged correlation coefficient = 0.67). Berry production represented a two-year cycle in western but a three-year cycle in eastern Norway. The abundance of the moth and the parasitoid also varied across years and were spatially synchronized. The degree of spatial synchrony decreased and cyclicity became obscure with increasing trophic level. We attempted to assess two different components to the predator satiation, functional and numerical satiations, based on a simple population dynamics model. The observed pattern of seed predation testified that both of functional and numerical satiations were at work in this system. In a comparison at different locations, rowan trees with more variable berry production were more effective in reducing losses to the seed predator. The parasitoids also seemed to experience satiation through the fluctuation in their host abundance. These results show that rowan masting has an adaptive foundation, which impacts the dynamics of higher trophic levels.
Redaktører
Johanne KjuusSammendrag
Det er ikke registrert sammendrag