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.
2006
Sammendrag
Bekjempelse av veksthusspinnmidd (Tetranychus urticae) og trips med rovmiddene Phytoseiulus persimilis (middrovmidd) og Amblyseius cucumeris (tripsrovmidd) kan være en utfordring i agurk som dyrkes med vekstlys og nedsenkingsmetoden. Mye lys (ca. 200 W/m2) og høy temperatur gjør at klimaet i toppen av plantene ofte blir for tørt til at middrovmidden trives, og mye rovmidd fjernes ved avblading. Artikkelen beskriver de to hovedstrategiene for biologisk bekjempelse av veksthusspinnmidd som brukes i veksthus med agurk, og gir råd om bruk av tripsrovmidd.
Sammendrag
Rovmidden Amblyseius swirskii ble godkjent mot trips og mellus i veksthuskulturer i Norge i juli 2006. Godkjenningen gjelder til 30/6-2012. Selv om A. swirskii bare har vært i salg siden 2005, er det lovende resultater blant annet fra agurk, paprika og snittroser. Det er interessant å prøve rovmidden i kulturer der det er angrep av trips og mellus samtidig og i kulturer med stort smittepress av amerikansk blomstertrips.
Sammendrag
Freezing and thawing influence the transport potential and pathways for contaminants by altering the soil physical properties. Firstly, soil frost delays or impedes infiltration of rain and meltwater, reducing the transport rate of dissolved contaminants. But at the same time, particle bound contaminants may be mobilised because the reduced infiltration capacity increases surface runoff and erosion risk. Secondly, freezing water expands and imposes mechanical stresses on the soil, which may cause aggregate breakdown and facilitate particle detachment and transport. The influence of repeated freezing and thawing on aggregate stability of different soils is poorly documented for Nordic winter conditions. The purpose of this study (Kværnø and Øygarden, subm.) was to quantify the effect of variable freeze-thaw cycles and soil moisture conditions on aggregate stability of three soils: Silt, structured clay loam (Clay A) and artificially levelled silty clay loam (Clay B). These soils are representative of two erosion prone areas in South-eastern Norway. Field moist surface soil was sieved into the fraction 1- 4 mm, and packed into cylinders. The water content of the soil was adjusted, corresponding to matric potentials of -0.75, -2 and -10 kPa. The soil cores were insulated and covered, and subjected to 0, 1, 3 or 6 freeze-thaw cycles: freezing at "15"C for 24 hours, and thawing at 9"C for 48 hours. Aggregate stability was measured in a rainfall simulator (representing rainfall) and a wet-sieving apparatus (representing surface runoff). The aggregate stability of Silt was found to be significantly lower than of Clay A and Clay B. Clay A and Clay B had similar aggregate stabilities, even if it was expected that the artificially levelled Clay B would have lower stability. Freezing and thawing decreased the aggregate stability for all three soils, but the effect was more severe on the silt soil. There was no evident effect of water content on the aggregate stability, probably due to experimental limitations. The wet-sieving apparatus resulted in less aggregate breakdown than the rainfall simulator. Rainfall impact seemed to be more detrimental than wet-sieving the more unstable the soil was, that is, after many freeze-thaw cycles, and on silt soil. The results indicate that freezing and thawing is an important factor influencing the erosion risk of the studied soils. In the future, climate change is expected to give more unstable winters with more freezing and thawing events. Combined with more precipitation as rainfall during the winter period both runoff and erosion will probably increase, possibly resulting in heavier loads of particulate bound contaminants to surface waters. The results are also helpful for improving predictions of contaminant fate and transport, as most of the existing hydrological and soil erosion prediction models do not satisfactorily describe soil processes occurring under Nordic winter conditions. This study focused on arable soils with conventional agricultural management, where plant nutrients and pesticides pose a threat to water quality. It would be useful to conduct similar experiments on soils where other organic and inorganic contaminants are of concern, e.g. on soils where sewage sludge and compost have been applied, and soils in road cuttings and on contruction sites. References Kværnø, S.H. & Øygarden, L. submitted: The influence of freeze-thaw cycles and soil moisture on aggregate stability of three soils in Norway.
Sammendrag
The performances of the plum rootstocks Ferlenain, Ishtara, Jaspi and P 8-13 compared with St. Julien A as a standard, for the cultivars `Opal" and `Reine Claude GF 1119" were assessed in a field trial in western Norway at 60° North. This trial was one part of an international plum rootstock trial located in seven European countries and organized from INRA Bordeaux. Trees were planted in spring 1994; spaced 2.0 x 4.0 m and formed with a central leader as free spindles. Soil management was grass in the alleyways and herbicide strips 1-m wide along the tree rows. Tree vigour, yield, fruit size and yield efficiency were evaluated for the seven subsequent years. Tree size was significantly affected by the rootstocks. P 8-13 produced the largest trees for both cultivars as measured by trunk cross-sectional area. The smallest trees were produced on Ferlenain for the cultivar `Opal" and on Jaspi for `Reine Claude". The cultivar `Opal" was the most productive and gave three times larger crop than "Reine Claude" on average for the six cropping years. The `Reine Claude" trees came two years later into production than `Opal". There were small differences between the different rootstocks in productivity: However, the rootstock Ferlenain produced significant lower crop than the other rootstock for `Opal". Trees on Jaspi were the most yield efficient for `Opal" and Ferlenain for `Reine Claude". The fruit sizes were in general medium to small for both cultivars and became little affected by the different rootstocks. The average fruit size was about 30 g for `Opal" and 25 g for `Reine Claude". Fruit quality characterized by the content of soluble solids was high for `Reine Claude" with average 20 % and 15 % for `Opal" and did not differ much between trees on the various rootstocks.
Forfattere
Sonja Klemsdal Karen Rae Bone May Bente Brurberg Erling Fløistad Roar Moe Dag-Ragnar BlystadSammendrag
The relative distribution of PoiBI in different tissues and in different parts ofthe plants was quantified using the comparative Ct method and a new developed TaqMan real-time PCR assay. Five samples were analysed from each of six different nodes equally distributed along the height of the plant. Also samples from the top of the plant, from the stem base and the primary and secondary roots were studied. The quantitative real-time PCR test proved to be a very sensitive test. Highest level of phytoplasma was found in the bark samples while the stem core samples contained little or no detectable phytoplasma. The lack of accumulation of phytoplasma in sink tissues indicates restricted phloem translocation of PoiBI. There were large plant-to-plant variations in PoiBI content and further studies including more plants will be needed in order to reveal the general distribution of PoiBI and its possible correlation to branching in poinsettia.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Oleif Elen Per-Erik Clasen Sonja KlemsdalSammendrag
I årene 2001-2004 ble 210 hveteprøver analysert for mykotoksinet DON. Høyeste mengden som ble påvist var 2600 µg/kg. Mengde Fusarium graminearum økte betydelig i denne perioden. Dette ble påvist både med tradisjonelle morfologiske metoder og ved kvatitativ TaqMan PCR. Vårhvetesorten Zebra hadde mest DON og vårhvete var mer utsatt for et høyt DON-innhold enn høsthvete.
Forfattere
Oleif ElenSammendrag
Mykotoksiner i kornet kan forebygges til en viss grad ved vekstskifte, pløying ved ensidig korndyrking, dyrking av sorter som er sterke mot fusarium og ved å unngå å dyrke korn på arealer med mye doggfall.
Forfattere
Oleif ElenSammendrag
Været har stor betydning for angrep av Fusarium.Hvis været er fuktig, kan bondens valg av dyrkingsfaktorer ha stor betydning for om det skal bli lite eller mye toksiner i kornet.
Sammendrag
To realize the full potential of agricultural biotechnology, concerns about the possible impact of GM plants on ecosystem properties and functions must be addressed. If transgenic crops substantially affect soil organic matter decomposition and mineralization, this could be of serious concern to many farmers in the developing world, as well as to organic farmers in the developed world. These farmers rely on local residues, organic matter and soil organisms for soil fertility, and there is a risk that this could be reduced if crop products cause a slowing down of the natural processes of decomposition and nutrient release by inhibiting the activity of the soil biota.