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.
2001
Forfattere
Lars SvensonSammendrag
Planteforsk Holt forskingssenter arrangerte i samarbeid med de andre Planteforsk-enhetene i Nord-Norge et fagmøte på Saltstraumen hotell 27.-28 mars 2001. Fagmøtet var et ledd i kunnskapsformidlingen som er et høyt prioritert mål for Planteforsk og innsatsområdet "Landbruk i nord". Innholdet var til stor del viet fôr og fôrvekster og med spesiell tyngde på det strategiske instituttprogrammet (SIP) "Avlingsstabilitet på grasmark i Nord-Norge" som avsluttes i løpet av 2001. For å sette den faglige delen i perspektiv tok åpningsforedragene også opp landbrukspolitiske spørsmål ved representanter fra stortinget og Fylkesmennenes landbruksavdelinger.Blant de faglige temaer var overvintringsproblematikken i eng sentral. Bruken av snø- is- og telemålinger for å kunne forutsi vinterskade ble tatt opp, sammen med en drøfting av sammenhengen mellom jord, terreng, drenering og risiko for vinterskade. Betydning av en riktig gjødslingspraksis for god overvintring var et annet tema.Utviklingen av plantebestanden ble satt i sammenheng med driftsintensitet, klima og terreng og det ble satt fokus på avlingsstabilitet og økonomien på det enkelte gårdsbruk. Overvintring og optimal alder på eng var viktige stikkord. Her foregikk også med en drøfting av mulige driftstilpasninger ved sviktende avlinger. Foredlingsanssvarlig i Planteforsk orienterte om nytt forbedret plantemateriale for engdyrkinga. Mulighetene for dyrking av korn til kraftfôr ble tatt opp i to foredrag.To forskingsprosjekter for det framtidige landbruket i nord ble presentert: Et storskalaforsøk med sammenligning av økologisk og konvensjonell melkeproduksjon og prosjektet "Landbruksbygg i Arktis" som arbeider med enklere og kostnadsbesparende bygg for nordområdene.Utnytting av beite i inn- og utmark er et blitt et viktig tema og dette ble belyst i tre foredrag.Fagmøtets avsluttende foredrag tok opp markedsmessige muligheter for potet og hagebruksprodukter.
Sammendrag
Potato leaf samples infected by Phytophthora infestans were collected from several potato fields at Jæren, Rogaland county in Norway, at different periods of the growing seasons in 1998 and 1999. Two conventional field and one organic field were sampled at intervals of one to two weeks throughout each season ("test fields"). Isolates of P. infestans were assessed for mating type and metalaxyl sensitivity. In 1998 and 1999, 21.7 % (n=50) and 52.7 % (n=170) of the isolates respectively, were A2 mating type. In most fields, both mating type A1 and A2 were present. A relatively stable frequency of mating type A1 and A2 was found during the season. Among 72 isolates from 1998, 29.2 % of the isolates were metalaxyl-resistant. In 1999, 19.2 % of 83 isolates were metalaxyl-resistant. No significant differences in metalaxyl sensitivity between different sampling dates were found in the test fields. Bulked data from all early and late samples showed a significantly higher percentage of metalaxyl-resistant isolates late in the growing season. A lower frequency of resistant isolates was found in samples from early potato cultivars than in early samples from late potato cultivars. The implications of the mixed mating type situation and reduced sensitivity to metalaxyl are discussed.
Forfattere
Tor J. JohansenSammendrag
Populations of carrot flies (Psila rosae Fabr.) may build up in areas where carrots are grown year after year. High numbers of flies normally result in larval damage and unmarketable carrot roots. An integrated strategy for controlling the "one generation" carrot flies in Northern Norway includes non-chemical methods like crop rotation, selecting suitable growing sites (isolated, wind exposed) and crop covers. Adjusting sowing and harvest times is seldom an option, as the carrots need the relatively short and cool growing season to complete growth. The carrot growers often have to apply insecticides to achieve a sufficient reduction in larval damage. In Norway, like many other countries, insecticides are applied when trap catches of adult flies exceed a certain threshold. The current insecticides are normally applied as drenches and are targeted against the young larval stages feeding on the carrot roots. Recently, high insecticide residues in carrots sprayed with fenthion were found and diazinon is now the only approved insecticide against carrot flies in Norway. To minimise the risk for residues, the pyrethroid lambdacyhalothrin is now being tested in field trials after promising results in laboratory tests. In addition to a well known "knock down" effect when the spray hits the flies directly, chemical residues on the carrot foliage may kill adult flies up to two weeks after spraying (cage tests). In our field trials, with small spraying plots, lambdacyhalothrin proved to be effective when the spray was applied soon after the first flies appeared. Application after the onset of egglaying, failed to prevent damage. This year (2000), we are performing experiments including treatment of whole fields with pyrethroids. The results from these trials will give a more realistic test of a possible new strategy in carrot fly control; killing adult flies instead of larvae.
Sammendrag
Biodiversity studies of insect pathogenic fungi are normally conducted by the use of Galleria mellonella (Lepidoptera) or Tenebrio molitor (Coleoptera) as bait insects. These insects are easy to obtain and handle and large numbers of fungal isolates are often obtained by the use of these standard bait insects, but they usually yield only a limited number of fungal species. It was therefore an aim to compare the standard bait insect G. mellonella with Delia floralis (Diptera), a soil dwelling pest of Brassica vegetables, as bait insect. A method for baiting soil samples with D. floralis larvae was developed, and a systematic survey was conducted on soils from northern Norway for insect pathogenic fungi. Fungal species identified in the study were Beauveria bassiana, Fusarium merismoides, Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was found more frequently when using D. floralis as the bait insect than when using G. mellonella. Comparisons between the occurrences of insect pathogenic fungi in organically versus conventionally farmed soil have so far only been undertaken on a minor scale. This study therefore also aimed to compare the abundance of insect pathogenic fungi in organically and conventionally farmed soil and in soil from arable fields and the adjacent semi-natural field margins. The study showed a significantly higher occurrence of insect pathogenic fungi in soils from arable fields of organically managed farms. No significant differences in the occurrence of insect pathogenic fungi were, however, found between the field margins of the two cropping systems.
Forfattere
J. Palmer Mekjell Meland A. Hann J. WünscheSammendrag
Apple fruit quality, particularly size, is known to be influenced by crop load; mean fruit weight declines as crop load increases. Far less is known, however, on the influence of the number of fruit on an individual fruit spur on the resulting fruit quality. In early November 2000 eight groups of eight multi-fruited spurs were selected on five trees of two cultivars, Royal Gala and Braeburn. Each group of eight spurs consisted of four terminal and four two-year-old spurs. Within each spur type, fruitlets were thinned to a) one king, b) one king and one lateral, c) one lateral or d) two lateral fruitlets. Initial fruit diameters were recorded a few days later. Fruit were strip picked in the middle of the normal harvesting period for each cultivar. Statistical analysis at harvest was restricted to spurs which had maintained their original complement of fruit, as in some cases doubles were only singles at harvest. Initial fruit size was a poor indicator of final fruit size. Final fruit weight was not significantly altered by having one or two fruit on a spur. The percentage blush was slightly reduced on the pairs with Royal Gala but not with Braeburn. Effects on fruit maturity (BGC, SPI, firmness, soluble solids) were non-significant. Fruit on terminal spurs were larger than on lateral spurs with both cultivars. Fruit maturity, however, tended to be more advanced on lateral spurs, particularly with Royal Gala.
Forfattere
Ole Martin EkloSammendrag
For å redusere bruken av plantevernmidler er det tatt i bruk nye teknikker bl. a. med nye jordarbeidingsmetoder, biologisk bekjempelse, framskaffing av plantemateriale som er resistent mot skadegjørere og integrert plantevern som kombinerer biologi og teknikk på ulike måter. Nye modeller er utviklet til å beregne skadeterskler for skadegjører før det får avlingsmessige eller økonomiske konsekvenser. Det utarbeides prognoser for utviklingsforløp for skadegjøreren og det utarbeides elektroniske varsel som gir beskjed når det er behov for å gjøre noe. Igangværende prosjekter som omhandler omhandler plantevernmidler og miljø er blant annet: (1)toksikologiske effekter av partikkelbundne plantevernmidler, (2)effekter av vegetasjonssoner for å hindre overflateavrenning av plantevernmidler, (3)effekten av organisk materiale på mobilitet av plantevernmidler, (4)fangdammer og effekten av ulikt materiale i fangdammene for å hindre avrenning av plantevernmidler, (5)biobed for å hindre punktkilder ved påfylling av sprøyteutstyr, (6) utvikling av beste dyrkingsstrategier til å redusere risiko for forurensning, (7)videreutvikling av webbasert rådgiving i forhold til skadeterskler prognoser og varsling, (8) og sprøyting av ugras etter behov basert på billedbehandling. Framtidige oppgaver vil være: (1) å få en bedre dokumentasjon på effekter på organismer, populasjoner og samfunn i samspill, (2)utvikle indekser til bruk for forvaltning og rådgiving for å angi risiko for utvasking og miljøfarlighet under norske forhold, (3)bruk av nye midler med høy biologisk aktivitet og tilstrekkelig metoder for å kvantifisere disse, (4)undersøke persistente, mobile og toksiske nedbrytingsprodukter, (5) følge opp problemstillinger rundt langtransporterte plantevernmidler som deponeres i de kaldere regioner med stor risiko for opphoping i næringskjeden, (6)større fokus på formuleringsstoffer (hormonhermere), (7) bruke rådgivingsmodeller som utnytter stedsspesifikk informasjon for å redusere risiko i miljøet.
Forfattere
Anne Falk Øgaard Tore Krogstad Anne-Kristin LøesSammendrag
In a pot experiment with five harvests of ryegrass the potassium (K) uptake from soil was studied in a clay and a silt soil, with (K1) and without (K0) K fertiliser. Ammonium acetate lactate extractable K (K-AL) was rapidly depleted, and in K0 the K-AL level stabilised at 30 and 100 mg K/kg in the silt and clay soil, respectively. Corrected for different "minimum" values, the K-AL value predicted the K uptake by ryegrass from AL extractable K very good. In the silt soil the K release from reserve K (total K release from soil minus K release from K-AL) was small, whereas in the clay soil there was a substantial release from reserve K. Part of the reserve K in the clay soil was easily releasable and contributed to luxury consumption of K in the first crop. Acid soluble K (K-HNO3 minus K-AL) was in this study a good parameter to assess the ability of the soil to supply ryegrass with reserve K. The results were compared with the results of the field experiments from which the soils were collected. The difference in K release between silt and clay soil was larger in the pot than in the field experiments, but without K fertilisation the K-AL values levelled off at the same values in field and pot experiments.
Forfattere
Bjørn Molteberg Frank EngerSammendrag
Verdiprøving av fôrvekster er en forvaltningsoppgave som Planteforsk Apelsvoll forskingssenter gjennomfører på oppdrag fra og etter retningslinjer gitt av Statens landbrukstilsyn (Landbrukstilsynet). Hovedmålet med verdiprøvingen i fôrvekster er å framskaffe forsøksresultater som skal danne grunnlaget for godkjenning av nye sorter for opptak på norsk sortsliste. Verdiprøvingen i fôrvekster er en kontinuerlig, ikke tidsavgrenset prøving, der de samme oppgavene gjentas fra år til år. Flerårige arter legges ut to ganger med tre registrerings- og høsteår etter hvert utlegg. Ettårige arter prøves i tre år. Artene blir som hovedregel prøvd i fem distrikter, Østlandet, Fjellbygdene, Vestlandet, Midt-Norge og Nord-Norge. Utlegging av forsøk, feltnotater i vekstsesongen og høsting av forsøkene gjennomføres i stor grad på Planteforsks resultatenheter, men det legges også en del felt i forsøksringer på Sør-Østlandet. All datainnlesing og resultatberegning foregår ved Apelsvoll forskingssenter. Siden dette er en kontinuerlig prøving, vil nye sorter komme med i prøving hvert år, og sorter som er ferdig prøvd, vil gå ut av prøvingen. Dette gjør at alle forsøksfelt har med sorter som har kommet med i prøvingen til ulik tid. I denne utredningen er kun sorter som er ferdig testet tatt med. I 2000 var det sorter innen artene timotei, engsvingel/raisvingel, rødkløver og italiensk raigras som var ferdig testet. I timotei ble feltene anlagt 1995 og 1997. Engsvingel/raisvingel ble anlagt i 1996 og 1997, og rødkløver ble anlagt både i 1994, 1995, 1996 og 1997, på grunn av stor utgang i 95 og 96. Italiensk raigras ble anlagt i 1996, 1997, 1999 og 2000. I alt 25 sorter var ferdig testet og av disse er kun 6 anbefalt godkjent, (1 raisvingel og 5 rødkløver).
Sammendrag
Seasonal production of spores (conidia) of Monilinia laxa (Aderh. & Ruhl) Honey on overwintering mummified fruits, blighted flowers and fruit spurs, and newly infected flowers of sweet cherry (Prunus avium L.) was investigated in Norway in 1997-1999. Infected plant parts were incubated in saturated air for 48 h prior to washing in distilled water, followed by a quantification of conidia from the spore suspensions with a light microscope. Mummified fruits or fruit spurs containing blighted flower and leaf parts, placed on the ground in the spring or the preceding autumn, more quickly depleted their inoculum compared to similar plant parts still hanging in trees. Conidia were produced in high numbers on mummified fruits left hanging in trees for 2-3 years after infection. In 1997, the conidial production on fruit mummies in trees was relatively even during the growing season. The year after, the highest sporulation on mummified fruits in trees occurred prior to flowering, and by harvest the sporulation was reduced by 92%. The wet weather that occurred in 1998 probably depleted the inoculum earlier than in 1997, when the summer was drier. The major production of conidia from fruit spurs occurred prior to or around bloom, and very few conidia were observed at harvest. Infected flower and leaf parts attached to the overwintering fruit spurs contained higher numbers of conidia than the fruit spurs themselves. Flowers infected in the spring produced most conidia during the first two months after infection, however, if remaining attached to the fruit spurs, they produced conidia during the entire season. Infected overwintered flowers produced 3-10% as many conidia as newly infected flowers in May and early June. The maximum production of conidia from single overwintered mummified fruits was more than 10 times the conidial production from an overwintered fruit spur or newly infected flower at their respective times of peak sporulation
Forfattere
Christian UhligSammendrag
A number of studies have been carried out on Cu concentrations in the soil solution close to Cu-Ni smelters in Finland and NW Russia. In these studies, however, the Cu concentrations represented the total Cu in the soil solution (as determined by AAS or ICP/AES), and speciation into e.g. free Cu2+ and organo-Cu complexes was not carried out. There is thus a need for methods for determining the toxic fraction (i.e. Cu2+) of the total Cu in the soil solution. This information can then be used to investigate the relationship between Cu2+ concentrations and e.g. microbial activity, and the functioning of roots and mycorrhizas in Cu-contaminated soils. Because a considerable amount of work has already been carried out on the speciation of Al in soil solution, the suitability of an Al fractionation procedure was first tested for Cu fractionation. However, because the Cu fractionation results obtained with this method were somewhat suspect, a Cu fractionation method developed by Berggren (1989) for relatively low Cu concentrations was tested and modified for soil solution samples containing high Cu and other heavy metal concentrations.