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
Temporal changes in the scores of selected soil fertility indices were studied over six years in three different cases of organic crop rotation located in southern, eastern and central Norway. The cropping history and the initial scores of fertility indices prior to conversion to organic cropping differed between the sites. Crop yields, regarded as an overall, integrating fertility indicator, were in all rotations highly variable with few consistent temporal trends following the first year after conversion. On the site in eastern Norway, where conversion followed several years of all-arable crop rotations, earthworm number and biomass and soil physical properties improved, whereas the system was apparently degrading with regard to P and K trade balances and contents in soil. On the other two sites, the picture was less clear. On the southern site, which had a relatively fertile soil before conversion, the contents of soil organic matter and K decreased during the six-year period, but the scores of other fertility indices showed no trends. On the site in central Norway, there were positive trends for earthworm-related indices such as worm biomass and tubular biopores, and negative trends for soil porosity. The results, especially those from the eastern site, illustrate the general difficulty in drawing conclusions about overall fertility or sustainability when partial indicators show divergent trends. Consequently, the study gave no unambiguous support to the initial working hypothesis that organic farming increases inherent overall soil fertility, but rather showed that the effect varied among indicators and depended on status of the cases at conversion. It is concluded that indicators are probably better used as tools to learn about and improve system components than as absolute measures of sustainability.
Forfattere
Thomas Hartnik Frans Busser John Jensen Joop HermensSammendrag
During the last years biomimetic extractions have become quite popular to assess the bioavailable fraction in soils and sediments. These techniques can be divided in depleting and non-depleting techniques, those that are based on depletion of the aqueous phase and subsequent desorption of the weakly bound fraction of a compound, and those that try to avoid disturbing the equilibrium between solid and aqueous phase. We have performed experiments that try to identify chemical extraction methods that mimic exposure of earthworms for the non-ionic insecticide "-cypermethrin. The extractable amounts that were achieved by the different extraction techniques were then related to internal concentrations in earthworms and sublethal toxicity for earthworms. Extraction of soil using ß-cyclodextrin was used as a depletive method. The extraction was based on a method developed by Reid et al (2000) and optimized regarding extraction time, cyclodextrin concentration and analysis of the extracted fraction. Non-depletive solid phase microextraction (nd-SPME) was used as a non-depletive technique. As shown earlier the technique can be used to assess concentrations of freely dissolved compound in porewater. Our results show that at low concentrations (< 25 mg/kg) cyclodextrin-extractability correlate well with uptake of "-cypermethrin in earthworm. However, at high concentrations ß-cyclodextrin tends to overestimate uptake in earthworms. Non depletive SPME-extraction precisely mimics the uptake of "-cypermethrin in earthworms both at low and high compound concentrations in soil. Differences between the extraction techniques will be discussed and explanation for the different extraction patterns given.
Sammendrag
The occurrence of Fusarium (represented by Fusarium spp. and Microdochium nivale) has been recorded in barley, oats and spring wheat seeds in Norway since the 1970-ies as part of the seed quality assessment. Annually a large number of samples representing both certified and farm saved seed from all cereal growing areas, was tested (100 or 200 seeds from each sample) at the Seed Testing Laboratory using the freezing blotter, the Doyer filter paper, and/or the agar plate (PDA) methods. In total, almost 30 000 samples of barley, more than 16 000 samples of oats and more than 9 000 samples of spring wheat were tested. The Fusarium frequencies were recorded in each sample, a mean of all samples was calculated each year for each cereal species, and multiple regressions with weather data from the growing season and also the Fusarium incidences in seed the previous year, were carried out. 69 % of the variation of the incidence of Fusarium in barley seeds was explained by 1) precipitation in July, 2) the incidence of Fusarium the previous year (both significant positive effects), and 3) precipitation in June, 4) temperature in July (both significant negative effects). In oat seed, precipitation in July and incidence of Fusarium the previous year explained 59 % of the variation. In spring wheat, as for barley and oats, precipitation in July and the incidence of Fusarium the previous year contributed positively, whereas precipitation in May and temperature in August had a negative effect.These four factors contributed significantly by 58% to the variation of Fusarium in spring wheat seed. It is concluded that the incidence of Fusarium in seed the previous year and precipitation in July were the main factors affecting the incidence of Fusarium in cereal seeds 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.
Sammendrag
Resultater fra forsøkene viser at i vårhvete vil en behandling med en strobilurinblanding i perioden fra begynnende skyting til full skyting gi en god beskyttelse mot hveteaksprikk. To ganger behandling kan være aktuelt i sorter med liten mjøldoggresistens. I gjennomsnitt for feltene i vårhvete i 2003-2005 var økningen i lønnsomhet ved to ganger behandling beskjeden i forhold til en gang behandling. I 25 % av forsøkene i perioden var det ikke behov for behandling. Tre ganger behandling var ikke lønnsomt i forsøkene. I forsøkene i høsthvete hadde en tidlig behandling med Stereo god virkning mot mjøldogg og på oppsmitting av hveteaksprikk. En tidlig behandling med et "ikke strobilurin", etterfulgt av en redusert eller full dose av en strobilurinblanding avhengig av sjukdomsrisiko vil ofte være en god strategi i høsthvete. Riktig tidspunkt for 2. gangs behandling må vurderes i forhold til værprognosene. 3 ganger behandling kan være aktuelt i høsthvete i år med vedvarende smittepress, og der årkeren har et høyt avlingspotensiale. Kartleggingen av sjukdommer i feltene har vist at det er en rekke sjukdommer til stedet i hveteåkrene, og at sjukdomsfloraen varierer noe fra felt til felt. Dette kan være en årsak til utslag som kan være vanskelig å forklare. Kartleggingen av hvilke bladflekksjukdommer som er til stede i forsøksfeltene er viktig for å kunne differensiere anbefalingene om bekjempelse bedre.
Sammendrag
During 2005 and 2006, 12 different fertilizer/biostimulant products or product families were evaluated on a new USGA green, a new sand-based football field, and/or a two to three year old USGA green at Bioforsk"s research units Landvik, Særheim and Apelsvoll in Southern Norway. Within each trial, all treatments were adjusted to the same total nitrogen rate per year (3.0/2.8, 2.5/1.7, and 1.75/1.75 kg N/100 m2 on the football field, new and established golf green in 2005/2006, respectively). Inputs of other nutrients varied among treatments. Application intervals varied among treatments in 2005, but most products were applied at biweekly intervals in 2006. Mineral fertilizers Arena® (small granules) and Fullgjødsel® were included as control treatments on golf greens and the football field, respectively. The mostly animal-based organic product families Suståne resulted in faster grow-in of the creeping bentgrass green at Landvik, while the products familiy ProGreen and ProGreen plus Activo had a similar effect on the football field established on straight sand at Særheim. When used as the only fertilizer source, neither these product families nor the animal-based product family Bio Kombi showed any advantage for maintenance of established turf The only product family resulting in a general improvement in turfgrass quality over the whole experimental period was Gro-Power®. This product family is based on humus, with all of its nitrogen in an easily available form. Unlike most other organic product families, it was tested in combination with mineral fertilizer Arena® as used in the control treatment. When used as the only fertilizer source, the seaweed product Golf Algin resulted in slower grow-in and more diseases in autumn than the control treatment. Used as maintenance fertilizer during summer, the visual ratings of Golf Algin plots were equal to or higher than the visual ratings of control plots. The liquid organic fertilizer Flex" resulted in slow establishment at Landvik and Særheim. In summer, the visual ratings of Flex" plots at these locations were mostly on level with or higher than control plots, but in autumn, the turf at Landvik became very light green, perhaps due to leaching losses. Like Golf Algin, Flex" seems to be a good maintenance fertilizer for the summer period. The seaweed product Maxicrop" had no effect on turf quality at Landvik. The biostimulant GoGreen improved turfgrass colour in autumn, but had no effect on winter diseases after almost five months of snow cover at Apelsvoll. By contrast, replacement of some of the Arena® fertilizer with ammoniumsulfate resulted in significantly better winter survival, root development and overall turfgrass quality in the same experiment. In conclusion, we recommend that fertilization of sand-based golf greens and football fields are primarily based on light and frequent applications of mineral fertilizer throughout the growing season. Organic fertilizers and biostimulants can never replace mineral fertilizer, but they are important supplements that warrant further research for optimal use.
Forfattere
Abdelhameed Elameen Solveig Haukeland Christer Magnusson Sonja Klemsdal May Bente BrurbergSammendrag
The pine wood nematode, Bursaphelenchus xylophilus, which is indigenous to North America, was introduced to Asia in the early 1900 and now causes severe damage to susceptible pine species in Japan, China, Korea and Taiwan. B. xylophilus was included in the A1 list of quarantine organisms by EPPO (European Plant Protection Organization) in 1985. B. xylophilus was reported for the first time in Europe in Portugal in 1999. There are more than 50 described species within the genus Bursaphelenchus worldwide, that are associated with coniferous and deciduous trees and spread by insect vectors. Within this genus is a group of morphologically very similar species; B. xylophilus, B. mucronatus, B. fraudulentus, B. kolymensis, B. conicaudatus and B. luxuriosae. This group of species is often referred to as the "B. xylophilus group". Due to the morphological similarity of the species, identification of Bursaphelenchus species in the B. xylophilus group is difficult. The common method of molecular identification for separating species within the B. xylophilus group is the use of ITS-RFLP (Hoyer et al. 1998). We have developed a multiplex polymerase chain reaction (PCR) method with specific primers, and the primers amplified product were 740, 340 and 300 bp for B. xylophilus, B. fraudulentus and B. mucronatus respectively. No cross reactions on the three studied species were observed. In contrast to the previously described PCR-RFLP method, this new method allows detection not only on pure isolates, but also on crude nematode suspensions from wood samples, and it could be very useful for quarantine purposes. References Hoyer U, Burgermeister W, Braasch H 1998 Identification of Bursaphelenchus species (Nematoda, Aphelenchoididae) on the basis of amplified ribosomal DNA (ITS-RFLP). Nachrichtenbl. Deut. Pflanzenschutzd. 50:273-27. Mota M M, Braasch H, Bravo M A, Penas A C, Burgermeister W, Metge K, and Sousa E 1999. First report of Bursaphelenchus xylophilus in Portugal and in Europe. Nematology 1:727-734. Smith, I. M. 1985. Pests and disease problems in European forests. FAO Plant Prot. Bull. 33:159-164. Yi C, Park J, and Chang K 1989. Occurrence of pinewood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and its vector, Monochamus alternatus Hope, in Korea. Pages 183-193 in: Proc. IUFRO Reg. Workshop For. Insect Pests and Tree Dis. in NE Asia. For. Prod. Res. Inst., Tsukuba, Japan.
Sammendrag
A new compact wastewater treatment system for use in single houses has been constructed in eastern Norway. The system is based on the principles of sub-surface flow constructed wetlands using various types of Filtralite as filter media. It consists of a septic tank followed by an aerobic biofilter succeeded by an upflow saturated filter. The aerobic biofilter is essential to remove organic matter and achieve nitrification, while the upflow filter polishes the wastewater and removes microorganisms and phosphorus. During the first 3 years of operation, the system has show stable and high removal with the following average values measured from the outlet of septic tank to the outlet of the upflow filter: 97.0%-BOD7, 30%-N, 99.4%-P, and 70.8%-SS. No Escherichia coli or somatic coliphages have been detected in the effluent. Due to considerable removal of organic mater, nutrients, and pathogens, the effluent will not negatively affect water and soil ecosystems. The system requires low maintenance and is designed to remove phosphorus for 5 years before renewal of the upflow filter media. When saturated with phosphorus, the media is a suitable fertilizer for plant production. (c) 2006 Elsevier B.V. All rights reserved.
Sammendrag
Methods for measuring prevalence of Neozygites floridana in a Tetranychus urticae population collected from strawberries were developed and compared. T. urticae were extracted from leaves using a soapy water solution (0.5 ml washing detergent : 8 l water) and then placed into 80% alcohol for use in methods 1 and 2. Method 1: N. floridana-sporulating T. urticae cadavers were observed and quantified under a compound microscope (40-80X). Method 2: Adult females were mounted in lactophenol cotton blue and observed for the presence or absence of N. floridana hyphal bodies under a microscope (200-400X). Method 3: Live T. urticae females were incubated at 25ºC and 75% RH and observed for mortality and N. floridana infection under a compound microscope (6.4-40X). Method 1 was the most time-efficient method and it also allows processing of samples as time permits. Method 2 quantified significantly higher fungal prevalence than method 1 and 3, but method 2 is not considered to be reliable because hyphal bodies are difficult to detect. No significant differences were found between methods 1 and 3.
Forfattere
Jørgen Aleksander Mølmann Olavi Junttila Øystein Johnsen Jorunn Elisabeth OlsenSammendrag
Seedlings of trees with a free growth pattern cease growth when night-lengths become shorter than a critical value, and this critical night-length (CNL) decreases with increasing latitude of origin. In northern populations, the light quality also appears to play an important role and a clinal variation in requirement for far-red (FR) light has been documented. In this study we dissected the light quality requirements for maintaining growth in different latitudinal populations of Norway spruce (Picea abies (L.) H. Karst.) using light emitting diodes for red (R), FR and blue (B) light, as 12 h day extension to provide 24 h photoperiod. At equal spectral photon flux, FR light was more effective than R light in maintaining growth, and the requirement of both R and FR increased with northern latitude of origin. One-to-one mixtures of R and FR light were more effective in maintaining growth than either FR or R light alone, indicating a possible interaction between R and FR light maintaining growth. Using the blue light as day extension could not prevent growth cessation in any of the populations, but delayed the bud set slightly in all populations. Our results suggest that phytochrome(s) are the primary photoreceptors in high irradiance responses maintaining growth in Norway spruce seedlings.