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.
2007
Forfattere
Jon Atle Repstad Trygve S. Aamlid Lars Tørres HavstadSammendrag
Norwegian agriculture is totally dependent on a safe supply of seed of winter-hardy timothy varieties. The annual seed consumption varies depending on the extent of winter damages, particularly in northern Norway, and the average seed yield varies with weather and harvest conditions in the seed-producing districts in the southeastern and central part of the country. To buffer these variations, seed companies always keep stocks corresponding to 50-100 % of the average annual seed consumption. Such large stocks are risky to maintain as seed lots will loose germination over time. Our objective was to elucidate the effect of seed harvest time and seed storage location on the longevity of timothy seed. In 2003, timothy `Grindstad" was combined directly on 2, 5 or 8 August corresponding to a seed moisture content (SMC) of 34, 27 and 20 %, respectively. After harvest the seed was dried to 10-11 % SMC. Germination analyses were accomplished 3, 15, 26 and 38 months after seed harvest; the three latter after splitting each seed lot into four sub-lots that were stored either in a conditioned seed store (4ºC, 30% RH), or in unconditioned warehouses at there climatically different locations. While seed harvest time had no effect on germination three months after harvest, differences became increasingly evident as time went by. After 38 months" storage, seed stored in the conditioned store or in the warehouse at the continental location Tynset germinated, on average for harvest times, 15-16 units better than seed stored in the warehouse at the coastal location Vaksdal; and seed lots harvested at 20 % SMC germinated, on average for storage locations, 24 units better than seed harvested at 37 % SMC. While it has long been documented that direct combining at high SMC may damage seed germination, there has been less awareness that this damage may not manifest itself until after a certain storage period.
Forfattere
John Ingar Øverland Trygve S. AamlidSammendrag
The application of plant growth regulators (PGRs) and insecticides, either alone or in tank mixture, was tested in nine on-farm trials laid out according to three different experimental plans in SE Norway (59-61ºN) from 2002 to 2006. The first plan compared the PGRs trinexapac-ethyl (125 or 250 g a.i. ha-1), chlormequat chloride (2000 g a.i. ha-1) and ethephon (240 g a.i. ha-1) applied on two dates and compared with an untreated check. On average for three trials, seed yield of the diploid cv. Nordi (origin 61ºN) increased 15 % by application of trinexapac-ethyl (250 g a.i. ha-1) at stem elongation, decreased 18 % by application of ethephone at flower bud emergence, and was not significantly affected by any of the other treatments. The diploid cv. Bjursele (two trials) and the tetraploid cv. Betty (one trial) showed no response to any of the PGRs. In the second experimental plan, laid out in two seed crops of the diploid cv. Lea in 2005, trinexapac-ethyl (125 or 250 g a.i. ha-1) was applied alone or in tank mixture with the insecticides alpha-cypermethrin (20 g a.i. ha-1) or dimethoate (500 g a.i. ha-1) on two dates. These trials verified the positive effect of trinexapac-ethyl, but the insecticides had no significant effect, which is not surprising as no harmful insects were detected. The third experimental plan compared insecticides at two developmental stages in a seed crop of cv. Lea with a high occurrence of Apion seed weevil and the lesser clover leaf weevil Hypera nigrirostris. In this trial, alpha-cypermethrin increased seed yield by 14 % when applied at flower bud emergence. Effective from 2004, Moddus 250 EC (trinexapac-ethyl) was approved in Norwegian seed production of selected cultivars of red clover. Research is still underway to evaluate the need for control of various weevils.
Forfattere
Trygve S. AamlidSammendrag
Foredraget gir en oversikt egenskapene til tunrapp, engrapp og engelsk raigras, de viktigste grasartene på norske fotballbaner
Forfattere
Trygve S. AamlidSammendrag
Foredraget gir en oversikt over de siste års forsøksresultater med ugrasbekjempelse ved frøavl av de tre artene.
Forfattere
Trygve S. AamlidSammendrag
De siste års viktigste forsøksresulater fra frøavl av kløver ble gjennomgått.
Forfattere
Trygve S. AamlidSammendrag
Foredraget gav en ovesikt over de siste års forsøksresultater med frøavl av timotei, engsvingel og rødkløver.
Sammendrag
Potettørråte vil også i 2007 kreve en aktiv bekjempelse. I likhet med de siste årene kommer vi med en omtale av varsling og middelvalg i forbindelse med bekjempelsen av denne viktige skadegjøreren. Artikkelen er en oppdatering av tilsvarende artikkel fra i fjor.
Forfattere
W.G Flier L.P.N.M Kroon Arne Hermansen H.M.G van Raaij B. Speiser L. Tamm J.G. Fuchs J. Lambion Jafar Razzaghian D. Andrivon S. Wilcockson C. LeifertSammendrag
Genetic variation and pathogenicity of Phytophthora infestans isolates collected from organic potato crops of the susceptible cv. Bintje and the moderately resistant cv. Santé were assesed in France, Norway, and the United Kingdom in 2001 and in Switzerland in 2001 and 2002. Population structures differed considerably between the four P. infestans populations. Those from France, Switzerland and the UK were mainly clonal populations showing restricted levels of genetic diversity, whilst those from Norway were mixed A1 and A2 mating type populations with high levels of genetic diversity, suggesting periodical sexual reproduction. Isolates collected from cv. Bintje were on average more aggressive than or comparable to isolates from cv. Santé. Race complexity varied considerably between the regional P. infestans populations with isolates from France and Switzerland showing the highest number of virulence factors. In all pathogen samples but the French, isolates collected from cv. Santé were more complex than isolates collected from cv. Bintje. No directional selection towards increased aggressiveness towards the more resistant cultivar Santé was observed. This suggests that there is no shift towards increased level of pathogenicity in P. infestans populations following the large-scale introduction of more resistant potato varieties in organic production systems in Europe.
Forfattere
Hans OvergaardSammendrag
Global change certainly affects the epidemiology of vector borne diseases (VBD). A changing climate may cause shifts in the intensity and endemicity of VBD"s. Both direct effects (e.g. changes in temperature and rainfall) and indirect effects (e.g. changing local environmental conditions) of climate change influence disease vectors and the disease-causing organisms they carry. Substantial research efforts are required to predict the effects of future climate scenarios on changes in magnitude and spatial distribution of VBD"s. Similarly, more research is needed to explore innovative locally-adapted solutions to control vectors and VBD"s. Two promising tools are presented, that can be implemented under local conditions and be adapted to changing environmental and climatic conditions. Integrated Pest and Vector Management (IPVM) is a strategy to simultaneously control both agricultural pests and disease vectors. The strategy is a combination of Integrated Vector Management (IVM) and Integrated Pest Management (IPM). IVM seeks to improve vector control by implementing synergistic combinations of interventions based on knowledge of local vector biology and disease transmission. IPM is the corresponding strategy in agricultural pest control and aims to reduce pesticide use for the benefit of human and environmental health. Both IVM and IPM preserve beneficial organisms and lessens selection pressure for insecticide resistance. These strategies can be implemented through Farmer Field Schools (FFS) " a participatory non-formal education approach teaching farmers how to reduce pesticide use through field observation and experimentation. These approaches ensure community empowerment for the benefit of health promotion, rural development, and preparedness for adverse global change effects.
Sammendrag
Good soil structure is recognised to be of key importance in organic farming, and soil compaction poses a major threat with respect to this. The relative importance of tractor weight (2-4 vs. 5-7 Mg), ploughing depth (ca. 15 vs. 25 cm) and wheel placement during ploughing (in-furrow vs. on-land) have been studied for four years on two soil types (well-drained loam and imperfectly drained silty clay loam) in southern and central Norway. On the site with imperfectly drained silty clay loam supposed to be most suceptible to soil compaction, the soil aeration and penetration resistance, but not the yield of barley, was affected by the treatments imposed. On the site with the well-drained loam, shallow ploughing with the heavier tractor and wheel in-furrow caused lower yields of wheat, but not of barley than did the other treatment combinations. This may partly be related to reduced air permeability and volume of air filled pores at 18-22 cm and partly to a higher incidence of perennial weeds after shallow than after deep ploughing.