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
Børge Holen Kim Johansen Marianne TomtumSammendrag
I 2006 ble det undersøkt 1691 prøver, derav 94 prøver av matkorn/ris, 45 prøver barnemat, 68 prøver av øl i et nordisk kartleggingsprosjekt, 88 prøver i nordisk kartleggingsprosjektet for vegetabilske produkter fra Asia og 20 prøver av appelsinjuice. Av de ordinære stikkprøvene var i 37 % norskprodusert, mens 63 % var importert. 151 av prøvene var merket økologisk. I alt ble 79 ulike vareslag av frukt, grønnsaker og korn fra 52 forskjellige land analysert. 37 forskjellige vareslag av barnemat analysert. Det ble undersøkt for inntil 244 virksomme stoffer inkludert noen nedbrytningsprodukter Av totalt 1206 analyserte prøver av frisk frukt, grønnsaker og poteter (ikke inkludert kartleggingsprosjekter) var 55,2 % av samlet prøveuttak uten påvisbare rester av plantevernmidler. Gjeldende grenseverdier (MRL= Maximum Residue Level) ble overskredet i 2,6 % av prøvene (0,9 % overskridelse i norske og 3,6 % i importerte produkter). Det ble påvist rester av 102 ulike plantevernmidler. Hvis en også inkluderer resultatene av kartleggingsprosjektetene, så var det totalt funnet overskridelser i 76 prøver av i alt 105 stoffer. I alt 16 av prøvene hadde overskridelser av mer enn ett stoff. De fleste overskridelser finnes i varer fra Thailand. Inkludert kartleggingsprosjektet var det i importerte varer flest overskridelser i bønner med belg (19 prøver), stangselleri (5 prøver) og chilipepper (4 prøver). Når det gjelder norske produkter, ble det påvist 5 overskridelser. Rester over grenseverdi ble påvist i to prøver av eple, en prøve av gulrot, salat og estragon. Ingen av disse hadde overskridelser av mer enn ett stoff. I 2006 ble 13 varepartier stoppet for rettet kontroll. Det ble påvist nye overskridelser i åtte av varepartiene og de kunne følgelig ikke omsettes. For barnemat ble det i 2006 tatt prøver av 45 varepartier, 35 norskproduserte og 10 importerte. Det ble ikke påvist rester av plantevernmidler i barnematprøvene. Det ble tatt ut 151 prøver av varer som var merket økologisk dyrket, hvorav 59 norske. Det ble påvist rester av plantevernmidler i fire av de importerte varene, men ingen i de norske økologisk merkede varene. I 2006 ble det gjennomført tre kartleggingsprosjekt for å undersøke innholdet av plantevernmiddelrester: "Appelsinjuice", "Vegetabilske produkter fra Asia" og "Øl". Det ble ikke påvist rester av plantevernmidler i 68 prøver av øl (44 importerte og 24 norske). I alt 20 prøver av appelsinjuice ble analysert i 2006. Det ble påvist rester av plantevernmidler i seks av prøvene (totalt åtte funn). Prosjektet "Vegetabilske produkter fra Asia" gav derimot svært mange og høye funn. Hele 49 % av prøvene inneholdt rester av plantevernmidler som overskred gjeldende grenseverdier. Spesielt i prøver av bønner med belg fra Thailand ble det registrert mange overskridelser. Av 94 analyserte korn- og risprøver var 65 % av samlet prøveuttak uten påvisbare rester av plantevernmidler. Det ble bare funnet én overskridelse i prøvene. Dette var rester av stråforkortningsmiddelet klormekvat over gjeldende grenseverdi i én prøve norsk rug. Det ble imidlertid noe oftere påvist rester i importerte matkorn i forhold til norskprodusert. I hovedsak har likevel frukt og grønnsaker som omsettes i Norge et lavt nivå av rester av plantevernmidler. Fra et helsefaglig synspunkt kan det konkluderes at restnivået i norskproduserte og importerte vegetabiler anses å representere svært liten helsefare.
Sammendrag
Supporting for the beneficial health effects of fruit is accruing apace. A subdivision of fruit, the berries, are increasingly becoming the focus of studies regarding their proposed ability to prevent or ameliorate the problems of degenerative diseases(McDougall et al, 2005; McDougall and Stewart, 2005) With respect to berries there has, over the last decade, been a groundswell of reports attributing beneficial biological activity to the fruit phenolics. The predominant approach in these studies is that of well defined in vitro systems employing mammalian cell models systems, such as Hela, Caco2 , HT29, Hep G2, etc to study absorption, anticancer, metabolism effects etc (Coates et al 2007; Ross et al, 2007). However, the direct translation of the benefits reported in these in vitro studies to in vivo results have lagged behind and are only now gathering pace. For example there are several intervention studies published highlighting or attributing their beneficial effects (albeit sometimes marginal) with regard to markers of colon and oesophageal cancer, cardiovascular disease, etc to the polyphenolic components in fruit. In addition, there are several major intervention trials either ongoing or planned and their focus is on fruit such as strawberry (cholesterol lowering), pomegranate (prostate cancer), blueberry (inflammation) and blackcurrant (CVD). This positive evidence with respect to the efficacy of fruit in the diet as a potential strategy to prevent, or at least retard, chronic and/or degenerative disease is leading to enhanced nutritive value now becoming a major target for plant breeders. However the lack of clarity as to the actual target means that breeding is not straight forward. Due to the chemical diversity of fruit, and specifically in berries, newer screening approaches have been adopted; metabolomics - LC-MSn, GC-ToF-MSn NMR etc. (Stewart et al 2007). We will discus how these approaches are being used in fruit breeding to study the inheritance of multiple silent phenotypes (chemotypes) in concert with map-based genetic approaches with a view to nutritional enhancement.
Sammendrag
Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest for the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occurre in T. urticae populations in fieldgrown strawberries? 2) How and where does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) How and where does N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to overwinter as both hyphal bodies in hibernating T. urticae females from October to at least February at temperatures as low as -20o C. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), preliminary results show that high numbers of spores (ca 1300-1900 per cadaver) were thrown at all three temperatures. Further, spores were thrown about the same distance (up to about 6 mm) at all three temperatures. The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempts to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.
Sammendrag
Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest for the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occurre in T. urticae populations in fieldgrown strawberries? 2) How and where does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) How and where does N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to overwinter as both hyphal bodies in hibernating T. urticae females from October to at least February at temperatures as low as -20o C. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), preliminary results show that high numbers of spores (ca 1300-1900 per cadaver) were thrown at all three temperatures. Further, spores were thrown about the same distance (up to about 6 mm) at all three temperatures. The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempts to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.
Sammendrag
Cover crops are included in cropping systems to achieve various ecological benefits. In stockless organic cereal systems, nitrogen is commonly supplied by undersowing a legume shortly after sowing of cereals. Retarded growth of annual weeds is considered as an additional benefit of using cover crops. There is, however, less knowledge on the influence of undersown cover crops on the growth of perennial weeds. This issue was addressed in a field experiment at Ås in southeast Norway. For obtaining an experimental field with uniform distribution of the perennial weed species, root fragments of Cirsium arvense and Sonchus arvensis and rhizomes of Elymus repens, were transplanted by hand in the spring of 2001. A split plot design with 3 replications was initiated in 2002 and continued until the autumn of 2006. Barley undersown with red clover versus barley alone composed the two main plot treatments, except in 2006, in which barley was grown without red clover in the whole field. This was combined with four sub-plot mechanical treatments in the autumn: 1) untreated control; 2) mowing; 3) rotary tilling and 4) shallow ploughing plus harrowing. The autumn treatments were only carried out in 2004 and 2005. Number of weeds was counted at different dates throughout the growing season, and weed biomass was assessed just before harvest. Preliminary results indicate that red clover undersown in barley, compared to barley alone, reduced the biomass of established stands of S. arvensis by 50%, 42% and 13% in 2004, 2005 and 2006 respectively. The effect on E. repens varied from +10% in 2004 to -42% in 2005 and -50% in 2006. There was no suppression on established stands of C. arvense (+10%, 0 % and +70%). Of the autumn mechanical treatments rotary tilling and shallow ploughing most effectively retarded the growth of perennial weeds, especially C. arvense and E. repens. Rotary tilling and shallow ploughing reduced mean weed biomass for 2005 and 2006 of C. arvense by 80% (rotary tilling) and 40% (shallow ploughing), and E. repens by 77% and 89%, respectively. Mowing and shallow ploughing reduced mean weed biomass for 2005 and 2006 of S. arvensis most effectively, with a reduction of 62% for both treatments. Although the results need more attention before detailed recommendations can be given, the study indicates clearly that the effect of different mechanical treatments in the autumn depend on weed species.
Sammendrag
Leakage of tributyltin (TBT) to coastal environment is documented globally and represents environmental hazards because of long half lives in anaerobic environment and accumulation in biota. Concentrations below 1 ng/l influence marine organisms. Hence, pollution control authorities request abatements to mitigate toxic concentration levels. Dredging of contaminated sediments is one abatement strategy, but this approach requires safe landfill repositories. An alternative strategy is to cover contaminated sea bottom areas by cap layers of favourable composition and thereby reduce TBT exposure to the environment. Both abatement strategies require understanding of chemical and physical processes involved at the pore scale and at the field scale. In the present study pore scale processes are investigated by laboratory experiments on dredged sediments from contaminated sea bottom and integrated to field scale by numerical simulations. The distribution of TBT between solid and water phase is a function of several parameters viz texture; composition of clay minerals; content of organic matter; pH; and salinity in the pore water. The influences of these parameters on the mobility of TBT in sediments are studied with emphasize on variable salinity flux through the porous media. In our data the mobility of TBT increases as a function of decreasing salinity. Long term leakage of TBT is simulated in a typified near shore landfill with initial marine salt water concentration in the pore water. Initial TBT concentration in pore water is estimated to 30 ng/l, which is corresponding to a chemical equilibrium of 1 mg/kg of TBT in the sediments. Because sorption of TBT varies as a function of salinity, the transport of TBT has to be coupled to concentration of NaCl in the pore water. The pore water flow depends not only on the relation between infiltration of meteoric water and permeability of the sediments, but also on the concentration of NaCl, thus Darcy law has to be coupled to transport of NaCl. In this way transport of TBT require a coupling of three types of physics. First is Darcy pore water flow coupled to concentration of NaCl, and then concentration of NaCl is coupled to desorption of TBT.
Sammendrag
The control of Alopecurus geniculatus, Poa annua and Poa trivialis using iodosulfuron (Hussar/Hussar OD) was investigated in field experiments in the seed harvest year in timothy (Phleum pratense), and in the sowing year and seed harvest year in smooth meadow-grass (Poa pratensis) and red fescue (Festuca rubra). Iodosulfuron (10 g a.i. ha-1) usually had good effect on Poa trivialis and Alopecurus geniculatus. As for Poa annua the effect on seed contamination was better than on weed coverage in the field. Early application improved weed control in the seed harvest years, and iodosulfuron was shown to perform well at low temperatures. The herbicide often delayed timothy development, but caused seed yield reduction only in two out of eight experiments, both with moist soil at treatment. The visual damage increased with increasing rates and use of additives (alcoholetoxylate or rape oil). A questionnaire investigation among timothy growers in 2004 showed that farmers using Hussar had 43% lower contamination of P. trivialis in cleaned seed yield and 20% lower yield than the farmers not using Hussar. In some trials in timothy and smooth meadow-grass, the new formulation Hussar OD gave slightly more damage than the old formulation Hussar. While well-established timothy crops seem to tolerate some visual damage without seed yield reduction, the risk of yield reduction in first year crops can usually be avoided by splitting the application into 5 g a.i. ha-1 at 14 days intervals. In smooth meadow-grass and red fescue established without cover crop, repeated applications of 5 g a.i. ha-1 in the sowing year resulted in better control of P. annua and significant seed yield improvements compared to application only in the seed harvest year. Both Hussar and Hussar OD have off-label approvals for members of the Norwegian Seed Growers Association.
Sammendrag
During 2002-2005, Norwegian seed yields of meadow fescue (Festuca pratensis Huds.) were 52% lower in organic than in conventional seed production. The difference was most conspicuous in ley year 1, suggesting that seed crop establishment is a limiting factor in organic seed production. Meadow fescue is usually underseeded in a cover crop of spring wheat or spring barley, and many organic growers delay the underseeding until after harrowing for weed control. Our objectives were (1) to determine whether organic seed crops of meadow fescue should be underseeded in the same operation as, or immediately after, the cover crop (implying no harrowing for weed control); or if they should be underseeded in conjunction with, or just after, weed harrowing (on average nine days after the cover crop); and (2) to compare the establishment of meadow fescue seed crops without cover crop or in cover crops of spring barley, spring wheat, peas or green fodder (barley + peas). On average for all cover crops and four trials, first year’s seed yields of meadow fescue were 11 % lower for crops seeded after weed harrowing than for crop seeded immediately after the cover crop. Weed harrowing combined with delayed seeding also resulted in more scentless mayweed (Tripleurospérmum inodórum) and other weeds in ley year 1. Despite less plant-available nitrogen in spring, seed crops underseeded just after the cover crop were more lodged than crops underseeded after weed harrowing. On average for the two seeding dates, the highest seed yield were produced from crops seeded in pure stand and from crops that had been underseeded in green fodder and received an extra 30 kg N ha-1 in manure shortly after green fodder harvest in late July. The results suggest that seed crops of meadow fescue need ample supply of light, water and nutrients in August to produce a good seed yield in ley year 1.
Forfattere
Bernt HoelSammendrag
I årene 2003-2005 ble det gjennomført forsøk med gjødslingstrategier til bygg (30 felt) og havre (16 felt) på Østlandet og i Midt-Norge. Med riktig valg av delgjødslingsstrategi, viser resultatene at en ofte kan oppnå en viss avlingsgevinst for delt gjødsling til bygg. I havre tyder resultatene på at potensialet for meravling ved delt gjødsling er mindre, men det er realistisk å kunne opprettholde avlingsnivået. Mange korndyrkere ønsker av ulike årsaker å benytte delt gjødsling til bygg og havre. Med en slik strategi kan dyrkeren ved vårgjødsling gi en gjødselmengde tilpasset en meget forsiktig avlingsforventning, ved delgjødslingstidspunktet kan bestandets potensial vurderes og gjødselmengden tilpasses dette. Denne justeringsmuligheten representerer en potensiell miljømessig og økonomisk gevinst. Både på leirjord og lettere jord kan gjødslinga ved såing være svak (5 kg N pr. daa ble prøvd i disse forsøkene), forutsatt at det følges opp med tidlig delgjødsling. Dersom en ved svak vårgjødsling venter med delgjødsling til begynnende stråstrekning risikerer en imidlertid et betydelig avlingstap, særlig på lett jord. En strategi som gir mer fleksibilitet omkring valget av delgjødslingstidspunkt er ei mer moderat vårgjødsling (8 kg N pr. daa i disse forsøkene). På leirjord kan en da anbefale å vente med delgjødsling til begynnende stråstrekning. En risikerer heller ikke på lettere jord noe stort avlingstap ved å utsette delgjødslinga til dette vekststadiet, dersom vårgjødslinga er moderat.
Forfattere
Stig Morten Thorsen Lars Egil HaugenSammendrag
In the process of studying how climatic changes will influence important forage crops at high latitudes, van Oijen et al. (2005) developed a plant model for two grass species, timothy (Phleum pratense L.) and perennial ryegrass (Lolium perenne L.). In order to study winter survival of the plants, the plant model requires routines to simulate winter conditions, such as snow accumulation, soil frost, ice cover and soil temperature. This report describes the development of the SnowFrost model that simulates snow accumulation and the formation of soil frost. Routines for simulating ice encasement will be added at a later stage. The SnowFrost model implements a degree-day-temperatureindex method in the snowmelt routines, and an energy balance approach to get an algebraic expression for soil frost formation. Our main focus when developing the winter model is to adequately simulate winter conditions from the plant's point of view, rather than accurately simulate the depths of snow cover and soil frost penetration. Simulations for a site with cold and stable winter conditions show promising results, and indicate that SnowFrost is suitable as a foundation for the continuing work of developing the winter routines for the plant model.