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.
2008
Forfattere
Ricardo Holgado Anette Stryken Christer Magnusson Irene Rasmussen Kari-Ann Strandenæs Bonsak HammeraasSammendrag
A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.
Forfattere
Ricardo Holgado Anette Stryken Christer Magnusson Irene Rasmussen Kari-Ann Strandenæs Bonsak HammeraasSammendrag
A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.
Forfattere
Arvid Steen Turid Strøm Aksel BernhoftSammendrag
Background Selenium is part of the antioxidant defence system in animals and humans. The available selenium concentration in soil is low in many regions of the world. The purpose of this study was to evaluate the effect of organic versus inorganic selenium supplementation on selenium status of ewes, their lambs, and slaughter lambs. Methods Ewes on four organic farms were allocated five or six to 18 pens. The ewes were given either 20 mg/kg inorganic selenium as sodium selenite or organic selenium as selenized nonviable yeast supplementation for the two last months of pregnancy. Stipulated selenium concentrations in the rations were below 0.40 mg/kg dry matter. In addition 20 male lambs were given supplements from November until they were slaughtered in March. Silage, hay, concentrates, and individual ewe blood samples were taken before and after the mineral supplementation period, and blood samples were taken from the newborn lambs. Blood samples from ewes and lambs in the same pens were pooled. Muscle samples were taken from slaughter lambs in March. Selenium concentrations were determined by atomic absorption spectrometry with a hydride generator system. In the ANOVA model, selenium concentration was the continuous response variable, and selenium source and farm were the nominal effect variables. Two-sample t-test was used to compare selenium concentrations in muscle samples from the slaughtered lambs that received either organic or inorganic selenium supplements. Results In all ewe pens the whole blood selenium concentrations increased during the experimental period. In addition, ewe pens that received organic selenium had significantly higher whole blood selenium concentrations (mean 0.28 "g/g) than ewe pens that received inorganic selenium (mean 0.24 "g/g). Most prominent, however, was the difference in their lambs; whole blood mean selenium concentration in lambs from mothers that received organic selenium (mean 0.27 "g/g) was 30% higher than in lambs from mothers that received inorganic selenium (mean 0.21 "g/g). Slaughter lambs that received organic selenium had 50% higher meat selenium concentrations (mean 0.12 mg/kg wet weight) than lambs that received inorganic selenium (mean 0.08 mg/kg wet weight). Conclusion Organic selenium supplementation gave higher selenium concentration in ewe and newborn lamb blood and slaughter lamb meat than inorganic selenium supplementation.
Sammendrag
In April 2007, orange-red pustules were found in needle scars on defoliated, dead shoots on a nordmann fir (Abies nordmanniana) Christmas tree in Rogaland County in south western Norway. A microscope slide made from the pustules revealed Fusarium-macrospores. On average they were 40.2 µm long and 2.9 µm wide (n=50). No microspores were found. A red coloured culture was obtained by transferring spore mass from a sporodochium to PDA (potato dextrose agar) with a sterile needle. The culture was transferred to SNA (spezieller nährstoffarmer agar) where macrospores developed. The majority of the spores had three septa, most of them were slightly curved, apically bent, basal cells were foot shaped, and spores were long and slender. Six singlespore cultures appeared identical on SNA. Two were chosen for an inoculation test. This test took place on 4 June 2007 in a polyethylene tunnel where the plants were kept during the whole experimental period. Nearly fully grown current year shoots on container grown nordmann fir transplants were inoculated by placing PDA agar plugs with fungal growth at the base of some unwounded needles on each shoot. Twelve transplants were used for each of the two isolates. The plants were covered with polyethylene bags for five days. After the bags were removed, the foliage was kept wet throughout the growing season by 1-3 minutes (depending on temperature) overhead irrigation every third hour. Brown shoots developed during the summer regardless of which singlespore isolate that had been used for inoculation. Samples from brown shoots were collected 20 October. No sporodochia, like we found under field conditions in April, had developed on the inoculated shoots. Neither did they develop after incubation in the laboratory. Only a whitish, fluffy mycelium was seen. CZID (Czapek dox iprodione dichloran agar) was used for reisolation from the dead shoots. From each group of 12 inoculated plants, two and three Fusarium-cultures were obtained, respectively. No symptoms were observed and no Fusarium sp. was isolated from the control plants (exposed to same treatment, but agar plugs with no fungal growth had been used). The Fusarium strain could not be accurately identified to species when the FUSARIUM-ID database v. 1.0 (http://fusarium.cbio.psu.edu) was searched with partial sequence of TEF (translation elongation factor 1-"). The original culture plus the two single spore cultures used for inoculation had identical TEF sequences which were most similar to F. acuminatum (97% identity). One out of six single spore cultures from each of the five reisolates, was sequenced. One of them matched the original culture, but the other four were most similar to F. avenaceum (98% identity). Different from the original culture, the F. av.-like isolates had both macro- and microconidia (0-3 septa, oval spore shape). On PDA, the F. ac.-like culture grew 25 mm in 72 hours (dark and 25°C) and the four F. av.-like cultures grew between 32 to 40 mm. They could not be distinguished by colour. Hyphal coils were found on both species, but were most prominent on the F. ac.-like culture. The fact that sequencing revealed involvement of two Fusarium-species, makes is difficult to draw conclusions about pathogenicity, but since the control plants showed no symptoms, there may be indications that the F. ac.-like fungus killed the inoculated shoots and that the F. av.-like fungus came in as a secondary invader from the environment inside or outside the tunnel. F. acuminatum is reported as a pathogen on conifer seeds and seedlings, but to our knowledge this is the first report of a F. ac.-like fungus causing dieback on a Christmas tree.
Sammendrag
Extensive damage by the needle parasites Delphinella abietis and Herpotrichia parasitica (Herpotrichia Needle Browning) was recently observed at the west coast of Norway. D. abietis was by far the most widespread, but once established in the field, the damage potential seemed to be equally high for both pathogens. D. abietis occurred on subalpine fir (Abies lasiocarpa), Turkish fir (A. bornmuelleriana), Siberian fir (A. sibirica), and nordmann fir (A. nordmanniana) in Christmas tree plantations, and minor damage was seen on Noble fir (A. procera) for bough production. H. parasitica was found on Turkish fir and nordmann fir in Christmas tree plantations. None of the diseases are new to Abies spp. in Norway, but they have not previously been reported from Christmas tree fields.
Sammendrag
To forskjellige strategier for fôring av ammekyr i inneperioden ble utprøvd ved Bioforsk Nord Tjøtta sitt storfefjøs gjennom to forsøksperioder, fra november 2006 til november 2008. Restriktiv gruppe ble fôret til å redusere kroppsholdet med 1 -1,5 holdpoeng (utnyttelse av kroppsreservene), mens normgruppen ble fôret til vedlikehold for ammekyr på ca 550 kg levendevekt. Kroppshold på kyrne ved innsett lå i overkant av 4, hvor tilrådningene er 3,0-3,5. Det opplevdes som vanskelig å fôre kyrne strengt restriktivt, da de viste atferdsendring som rastløshet og brøling når de ikke hadde nok fôrtilgang. Fôringsregimet måtte derfor justeres noe gjennom perioden av hensyn til bl.a. dyrevelferd. Holdet på kyrne ble ikke redusert i den grad som forventet i noen av forsøksperiodene. Det ble ikke funnet noen signifikant forskjell på kalvenes fødselsvekt, utslippsvekt, høstvekt og tilvekst inne og på beite mellom gruppene. Tilvekst hos kalvene i inneperioden var tilfredsstillende begge år og det opptrådte ingen sjukdom som følge av forsøket noen av årene. Fôringsforsøket viste at strategien med å fôre restriktivt for å spare vinterfôr og utnytte kroppsreservene til et visst nivå kan gi tilfredsstillende produksjonsresultater i form av fruktbarhet, kalvetilvekst og kalvehelse. Det må i et slikt fôringsopplegg tas hensyn til dyrevelferden, ved at kyrne får tilfredsstilt sitt behov for vomaktivitet og tidsfordriv gjennom hele døgnet. Dette kan løses ved å gi lavenergifôr i større mengder (for eksempel ubehandlet halm eller seint høstet gras), slik at rasjonen strekkes mer utover dagen.
Forfattere
Roald AasenSammendrag
Forsøket var en delundersøkelse i dokumentasjonen av et nytt avløpsfritt rensekonsept for svartvann fra toalett. På campus til UMB på Ås i Norge ble det under to sommerperioder, to vintrer, en høst og en vårperiode målt fordampning av vann fra et barkbasseng plassert under en betongrampe med to åpne sidevegger. Under sommerforhold ble det målt en fordampning på fra 0,9 til 1,1 kg vann/m2 døgn når vannspeilet lå fra 0 til 10 cm under toppen av barklaget. Når vannspeilet lå dypere sank fordampningen til 0,2 og 0,13 kg vann/m2 døgn. Under vinterforhold ble fordampningen målt til 0,25 kg vann/m2 døgn. Fordampningen på vinterstid skjedde hovedsakelig i mildværsperioder hvor deler av vannet nær overflaten smeltet. For å øke fordampningen bør en større del av barken i umettet sone komme i kontakt med gjennomstrømmende luft ved at overflaten økes ved bruk av barkranker, en aerodynamisk utforming av luftstrømningskanalen over barkbassenget, utformingen av bassenget og eventuell bruk av vifter. Varmekabler kan brukes under vinterforhold for å redusere isdannelse i barkbassenget.
Sammendrag
Hydrologiske karakteristikker fra mindre norske jordbruksdominerte nedbørsfelter ble presentert med særlig vektlegging av de ekstreme forhold. Fordeling av årsavrenning, antall dager det tar for å drenere 50 og 90 % av åravrenning, forskjellen mellom gjennomsnittlig døgnavrenning og maks døgn avrenning, flashiness komstante mm. Hva skal være konsekvensen for erosjon, næringsstofftap med klimaendringer.
Forfattere
Trygve S. AamlidSammendrag
Målet med den svenske frøavlskampanjen "Vallfrö 10000" er å øke produksjonen fra dagens 7000 tonn til 10000 tonn innnen 2010. Samtidig skal gjennomsnittsfrøavlingene økes med 10%. Sverige er allerede i dag (2008) verdens største produsentland for økologisk frø. I denne artikklen har vi intervjuet leder for kampanjen, Thorsten Rahbek Pedersen.
Sammendrag
Rovtegen Orius laevigatus, rovmidden Neoseiulus californicus og nyttenematoden Heterorhabditis bacterophora ble brukt i biologisk bekjempelse i Norge før den nye godkjenningsordningen for nytteorganismer ble innført i 2001. Artene ble ikke godkjent ved vurderingen i 2001 på grunn av uklar systematikk, fare for genetiske innblandinger, usikkerhet rundt naturlig utbredelse og etableringspotensial, og at artene ikke var påvist i Norge. Næringen ønsker å få de 3 artene tilbake på markedet. I vekstsesongen 2007 gjennomførte vi derfor på oppdrag fra Mattilsynet en kartlegging for å undersøke om O. laevigatus, N. californicus og H. bacteriophora har etablert seg i Norge. Vi samlet inn prøver både i områder der artene har vært brukt og i andre områder med mildt klima. Prøvene ble tatt i habitat som så langt det var mulig tilsvarer artenes habitat i det naturlige utbredelsesområdet. Vi fant 91 tegearter, men ikke O. laevigatus. Det ble gjort ett funn av N. californicus på en kompost utenfor et veksthus tidligere har benyttet rovmidden i sin produksjon, og som har mottatt plantemateriale fra en annen produsent har hatt N.californicus i kultur i gartneriet sitt. Dette funnet er ikke tilstrekkelig for å si at rovmidden er etablert i Norge. H. bacteriophora ble ikke funnet. Kuldetoleranseforsøk med 2 populasjoner med ulikt opphav av hver av artene O. laevigatus og N. californicus ble gjennomført i klimaskap ved -12oC, -6,5oC, og 3,0oC (konstant temperatur), og det ble gjort overvintringsforsøk med disse artene på friland i Ås og Lillestrøm i januar-mars 2008. Begge artene døde raskt ved alle de konstante temperaturene. I overvintringsforsøkene ble det funnet overlevende O. laevigatus etter 2 uker, mens N. californicus overlevde i nesten 2 måneder.