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
Fykse Haldor Haldor FykseSammendrag
In stockless organic cereal systems undersowing a legume shortly after sowing of cereals is a commonly used practice. Nitrogen supply as well as retarded growth of annual weeds is mentioned as benefits of such use of legumes in cropping systems. There is, however, limited knowledge on the influence of undersown cover crops on the growth of perennial weeds. This issue was addressed in a field experiment (#1) at Ås in South-eastern Norway. Furthermore, a second series of field experiments (#2) aimed at investigating the influence of (i) time of ploughing and (ii) that of black fallow. To obtain a field (#1) with uniform distribution of the perennial weed species, root fragments of Cirsium arvense (L.) Scop. and Sonchus arvensis L. and rhizomes of Elymus repens (L.) Mould., were transplanted by hand in the spring of 2002. The experiment, designed as a split-plot with 3 replicates, was initiated in 2003 and continued until the autumn of 2006. Oat undersown with red clover versus oat alone composed each year the two main plot treatments, except in 2006, in which the whole field was seeded to oat without red clover. Each mean plot was divided into four sub-plots with mechanical treatments in 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. The number of weeds was counted at different dates throughout the growing season, and the weed biomass was assessed just before harvest. Preliminary results showed that red clover undersown in oat, compared to oat alone, had limited and in most cases insignificant effects on biomass and number of shoots of all investigated species. No significant interaction between red clover and mechanical treatments in autumn was found. Shallow ploughing suppressed E. repens most, followed by rotary tilling, mowing and untreated, in that order. On S. arvensis, mowing showed the best control, and rotary tilling the poorest. On C. arvense, significant differences between treatments were detected only in 2005, when rotary tilling and shallow ploughing reduced the weed biomass significantly compared to the untreated control.In the second experiment series (#2) C. arvense, S. arvensis and E. repens are subjected to the following treatments: 1) black fallow (soil cultivation) + ploughing in autumn 2) ploughing in autumn 3) spring ploughing, and 4) black fallow + ploughing in spring. Preliminary results from the first experimental year have shown very clear interactions between treatment and weed species: Time of ploughing did not influence the growth of E. repens significantly. On the other hand fallow in autumn suppressed this species more efficiently than fallow in spring. In general, C. arvense and S. arvensis showed the opposite behaviour regarding both time of ploughing and effect of fallow. Spring ploughing, as well as spring fallow, suppressed these species more than treatments in autumn. However, not all comparisons were significantly different. Although the results need more attention as well as new experiments before detailed recommendations can be given, the studies indicate clearly that the effect of different treatments including time of ploughing and soil cultivation periods depends on weed species.
Forfattere
Knut Anders Hovstad Silje Borkvik Mikael OhlsonSammendrag
Epizoochorous seed dispersal on the red fox was examined by walking a fox dummy through a semi-natural grassland and comparing seeds found on the dummy to estimated seed availability in the vegetation. The potential for seed attachment in different species were compared using an index, Iseed, defined as the number of seeds on dummy after a fixed distance, divided by seed density (1000 seeds sq-m) in the vegetation. Seed attachment was related to plant and seed traits by fitting a zero-inflated negative binomial model. Only species with mature seeds, i.e. seeds that could be dispersed naturally, were included in the analysis and the results presented are means from ten independent runs. Twenty-nine species with mature seeds were observed in the vegetation and 19 of these species (4500 seeds in total) were found on the fox. Most of the seeds that attached to the coat originated from a few species. The most common seeds on the dummy were from the grasses Deschampsia cespitosa (84.2 %) and Agrostis capillaris (6.2 %), whereas the most abundant herb seeds on the dummy were Rumex acetosa (2.9%) and Ranunculus acris (1.9 %). The number of seeds available in the vegetation differed greatly among species, and when adjusted for seed availability, Geum rivale and Festuca ovina had the highest potential for seed attachment as judged by the index Iseed. In some species, Iseed displayed large variations due to a patchy distribution. Seed attachment was positively related to plant height, and bristle and hooked seed appendages, whereas it was negatively related to winged appendages, seed mass, and round seed-shape. However, also species without specific seed traits supposed to enhance epizoochory, attached some seeds on the fox, and our results support the view that a wide range of seed types can be dispersed in the fur of mammals. In summary, the results suggest that red fox can be an important seed dispersal vector in the agricultural landscape. A complete description of the experiments and results will appear in Journal of Vegetation Science in 2009.
Forfattere
Haithem Bahri Daniel Rasse Cornelia Rumpel Marie-France Dignac Gerard Bardoux Andre MariottiSammendrag
Recent in situ 13C studies suggest that lignin is not stabilised in soil in its polymerized form. However, the fate of its transformation products remains unknown. The objective of the present research was to provide the first comprehensive picture of the fate of lignin-derived C across its transformations processes: 1) C remaining as undecomposed lignin molecules, 2) C in newly formed humic substances, i.e. no longer identifiable as lignin-polymer C 3) C in microbial biomass, 4) C mineralised as CO2, and 5) dissolved organic C. To achieve this objective, we designed an incubation experiment with 13C-labelled lignin where both elementary and molecular techniques were applied. Lignin was isolated from 13C labelled maize plants (13C-MMEL) and incubated in an agricultural soil for 44 weeks. Carbon mineralisation and stable isotope composition of the released CO2 were monitored throughout the incubation. Microbial utilisation of 13C-MMEL was measured seven times during the experiment. The turnover rate of the lignin polymer was assessed by 13C analysis of CuO oxidation products of soil lignin molecules. After 44 incubation weeks, 6.0% of initial 13C-MMEL carbon was mineralized, 0.8% was contained in the microbial biomass, and 0.1% was contained in dissolved organic C form. The compound-specific 13C data suggest that the remaining 93% were overwhelmingly in the form of untransformed lignin polymer. However, limited transformation into other humic substances potentially occurred, but could not be quantified because the yield of the CuO oxidation method proved somewhat variable with incubation time. The initial bacterial growth yield efficiency for MMEL was 31% and rapidly decreased to plateau of 8%. A two-pool first-order kinetics model suggested that the vast majority (97%) of MMEL lignin had a turnover time of about 25 years, which is similar to field-estimated turnover times for soil-extractable lignin but much longer than estimated turnover times for fresh plant-residue lignin. We conclude that natural lignin structures isolated from plants are rather unreactive in soil, either due to the lack of easily available organic matter for co-metabolism or due to enhanced adsorption properties. The data also suggest that fairly undecomposed lignin structures are the main reservoir of lignin-derived C in soils.
Forfattere
Jerry Cross Catherine Baroffio Alberto Grassi David Hall Barbara Labanowska Slobodan Milenkovic Thilda Nilsson Margarita Shternshis Christer Torneus Nina Trandem Gabor VetekSammendrag
The sex pheromone of the raspberry cane midge has been identified and synthesised by East Malling Research and Natural Resourced Institute and has proved to be highly attractive and useful for pest monitoring. EMR coordinated a collaborative ring test of standard raspberry cane midge sex pheromone traps in 2006. The aims were to investigate the seasonal temporal pattern of the midge flight in different raspberry production regions of Europe and the relationship between the magnitude of catches and the numbers of eggs and larvae which developed subsequently in artificial splits in the primocane of untreated raspberry plantations. The standard raspberry cane midge sex pheromone trap used for the ring test consisted of a white delta trap containing a 20 x 20 cm sticky base and a rubber septum lure impregnated with 10 μg of the raspberry cane midge sex pheromone racemate. Pairs of traps, separated by >20 m, were deployed in the centre of raspberry plantations at a height of 0.5 m in Italy, Hungary, Norway, Poland, Russia, Serbia, Sweden, Switzerland, and the UK. The traps proved effective and easy to use for monitoring the flight of adult male raspberry cane midge. There were very large variations (> 30 fold) between plantations in total numbers of midges caught over the season, indicating plantations which are at comparatively low and high risk from the pest. Three generations of adult flight were apparent in Norway, Russia and Sweden and four generations in the central European countries with possibly 5 generations in Italy, though later generations were often difficult to distinguish. In the northern countries, the 1st generation first and peak flight occurred on Julian days 150 and 165, respectively, whereas in Italy the 1st generation first and peak flight occurred approximately on Julian days 110 and 130 respectively. The 1st generation flights occurred much earlier in polytunnel protected crops than in open field crops. Data obtained on the occurrence of larvae were variable in quality but a linear relationship between the peak numbers of males captured in the pheromone traps per week for a given generation (M) and the peak numbers of eggs and larvae per cm in splits in the primocanes for that generation subsequently (L) was apparent (L = 0.025 M; R2=0.61). A nominal threshold of 30 midges per trap per week had been proposed but the linear relationship derived indicates that this threshold, which would result in ~ 0.75 eggs + larvae/cm, is too high. In reality, the degree of larval infestation that occurs and the resultant severity of crop damage will depend on the numbers of natural splits in the crop. The ring test is being continued in several countries in 2007.
Forfattere
Claire E. Sansford Richard H. A. Baker John P. Brennan Frank Ewert Beniamino Gioli Alan Inman Anne Kinsella Håkon A. Magnus Franco Miglietta Gordon M. Murray Angelo Porta-Puglia John Roy Porter Trond Rafoss Luca Riccioni Fionnula ThorneSammendrag
Tilletia indica, soppen som forårsaker sjukdommen Karnal bunt i hvete, er listet som en I/AI karanteneskadegjører i EU (Anon., 2000a). Dette betyr at den anses som fraværende fra EU området, er potensielt skadende og dermed ikke ønsket innført til EU. Oppføringen som en karanteneskadegjører for EU er resultatet av en pest risiko analyse (PRA) (Sansford, 1996, 1998), som vurderte potensialet for innførsel, etablering og uønskede virkninger for Storbritannia og EU etter de første rapportene om utbrudd av denne sjukdommen i USA i 1996 (Ykema et al., 1996). Denne PRA"en ble oppdatert i 2004 (Sansford, 2004) og nylig grundig revidert (Sansford et al., 2006) for EU området. Denne nye EU-PRA"en fortsetter å støtte oppfatningen om at T. indica har potensial til å ankomme, etablere seg og forårsake uønskede økonomiske virkninger ute i store deler av hvete dyrkings områdene i EU. To nylig publiserte artikler (Jones, 2007a,b) har utfordret denne oppfatningen og EU-PRA"en for T. indica (Sansford et al., 2006). I dette brevet oppsummerer vi arbeidet av et fireårig samarbeidsstudie og går igjennom hovedpunktene som Jones (2007a,b) tar opp og tilbakeviser hans konklusjoner, spesielt angående (i) tidligere muligheter for innførsel av patogene til Europa; (ii) de klimatiske kravene for gjennommføring av livssyklus for T. indica, som leder til sjukdommen Karnal bunt; (iii) inokulum terskler; (iv) potentsiell økonomisk skade forårsaket av sjukdommen i Europa; og (v) kostnader ved kontroll og bekjemping. De fulle resultatene fra studiet er tilgjengelige on line (http://karnalpublic.pestrisk.net/) sammen med publiserte resultater for teliospore overlevelse og spiring i Europa (Inman et al., 2008) og mottakelighet i europeiske hvetesorter for T. indica (Riccioni et al., 2008).
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.
Forfattere
Kim Johansen Ingunn H. Gudmundsdottir Børge HolenSammendrag
I 2007 ble det i overvåkingsprogrammet for rester av plantevernmidler i vegetabilske næringsmidler undersøkt 1423 prøver, derav 90 prøver av matkorn/ris og 37 prøver barnemat. I eget kartleggingsprosjekt ble det analysert 30 prøver av klementiner for å se på fordelingen av plantevernmiddelrester i henholdsvis hele frukten, skall og fruktkjøtt separat (grenseverdiene er for hele frukten). Av de ordinære stikkprøvene var i 40 % norskprodusert, mens 60 % var importert, henholdsvis 62 % fra EU og 38 % fra tredje land. 106 av prøvene var merket økologisk. I alt ble 79 ulike vareslag av frukt, grønnsaker og korn fra 54 forskjellige land analysert. I tillegg ble 32 forskjellige vareslag av barnemat analysert. Det ble undersøkt for inntil 270 virksomme stoffer inkludert noen nedbrytnings¬produkter. Tre prøver ble sendt inn etter enkelthenvendelser, men ingen av disse inneholdt rester av plantevernmidler over grenseverdi. Av totalt 1248 analyserte prøver av frisk frukt, grønnsaker og poteter (klementinprosjekt ikke inkludert) var 53,4 % av samlet prøveuttak uten påvisbare rester av plantevernmidler. Gjeldende grenseverdier ble overskredet i 2,6 % av prøvene (0,6 % overskridelse i norske og 3,9 % i importerte produkter). Det ble påvist rester av 117 ulike plantevernmidler. Totalt ble det påvist overskridelser i 32 prøver av i alt 36 stoffer. Kun tre av prøvene hadde overskridelser av mer enn ett stoff. Ingen land eller produkter utmerket seg spesielt når det gjelder overskridelser i 2007. Når det gjelder norske produkter, ble det påvist tre overskridelser. Rester over grenseverdi ble påvist i to prøver av stangselleri og en prøve av purre. Ingen av disse hadde overskridelser av mer enn ett stoff. For barnemat ble det i 2007 tatt prøver av 37 varepartier, 27 norskproduserte og 10 importerte. Det ble påvist rester av stråforkortningsmiddelet klormekvat i syv norskproduserte barnegrøter, men det var i henhold til regelverket og det var ingen helsefare forbundet med funnene. Det ble tatt ut 106 prøver av varer som var merket økologisk dyrket, hvorav 29 var norskproduserte. Det ble påvist rester av skadedyrmiddelet endosulfan i én prøve sommersquash fra Italia. Påvisningen var under grenseverdi for konvensjonelt dyrket sommersquash, men ble fulgt opp av Debio pga brudd på økologiregelverket. I 2007 ble det gjennomført ett kartleggingsprosjekt for å se på hvor mye av plantevernmiddelrestene man finner igjen i skall og fruktkjøtt av klementiner. Resultatene fra prosjektet viste ingen høye funn, men så man på fordelingen i henholdsvis fruktkjøttet og skallet var hovedandelen av funnene i selve skallet. Av 90 analyserte korn- og risprøver var 69 % av samlet prøveuttak uten påvisbare rester av plantevernmidler. Rester av stråforkortningsmiddelet klormekvat ble oftest påvist, etterfulgt av ugrasmiddelet glyfosat. Alle påviste rester var under eller uten grenseverdi. Resultatene viser at frukt og grønnsaker som omsettes i Norge fortsatt har et lavt nivå av rester av plantevernmidler. Fra et helsefaglig synspunkt kan det konkluderes at restnivået av plantevernmidler i norskproduserte og importerte vegetabiler anses å representere svært liten helsefare.
Forfattere
Tor Håkon SivertsenSammendrag
Climate change scenarios provide alternative plausible future climate for the planet, each being an example of what might happen under a particular set of assumptions. Scenarios are not specific predictions or forecasts. Scenarios provide starting points for examining questions about the uncertain future climate.Some of the main processes connected to exchange of energy of the atmosphere of the planet usually are connected to radiation of short wave and long wave electromagnetic radiation. The global albedo of the short wave radiation is one important parameter, and the processes connected of the greenhouse gases water vapour and carbon dioxide in the atmosphere are extremely important elements of future scenarios.The total amount of output of fossil carbon into the atmosphere is of importance as well as the natural cycle of the carbon. Also there exist several important positive feedback systems. The amount of water vapor in the atmosphere is connected to the temperature of the air, or to be more specific the saturation vapour pressure of the water in the air is increasingly dependent on the temperature of the air. Usually a warm atmosphere then will contain more water vapour than a cold atmosphere, and this will make the atmosphere even warmer because water vapour is the most important greenhouse gas connected to long wave radiation.The ice cover of the Arctic and Antarctic regions as well as the glaciers in the high mountainous areas on the Earth are important for keeping the albedo of the short wave radiation of globe high. When the glaciers and the ice cover are melting, the albedo is decreasing and the consequence seems to be even more melting of ice.The ultimate worst case scenario seems to be that the ice cover and the glaciers of the planet melt down and the oceans receive all this water. The present situation seems to be like this:The total energy of short wave radiation, received by the planet: 100 unitsPlanetary albedo: 30%Total energy connected to the water cycle. 21 unitsAmount of yearly precipitation totally: 1000mmAverage residence time of a water molecule in the atmosphere: 10 daysTotal volume of ice on the planet: 33 x 106 km3 (~ 60 m of sea level equivalent)Total amount of CO2 in the atmosphere: 385 ppmIn order to understand the content and the challenge of the different scenarios I would like to know the value of the following parameters (every 5th year) of the scenarios:AlbedoTotal energy connected to the water cycleAmount of yearly precipitation totallyAverage residence time of a water molecule in the atmosphereTotal mass of ice on the planetTotal amount of CO2 in the atmosphere
Sammendrag
Oil transport from the Russian Arctic. Is the Barents Sea environment at risk? The volumes of oil being transported by sea from the Russian Arctic along the coast of Northern Norway were insignificant before 2002. In 2006, however, a total of 10 million tons of Russian export oil and oil products were shipped from Russia, on ships that sailed along the coast of Norway. The annual oil exports from the Russian Arctic regions via this Northern route may reach a total of about 50-80 million tons in the next decade. About 50 million tons of crude oil and oil products are estimated to be delivered by railway to the Murmansk ports in the Barents Sea, and to Kandalaksha and Arkhangelsk in the White Sea. Furthermore, up to 20 million tons of oil will be produced in the northern oil fields in the Nenets Autonomous Region and in the Pechora Sea. The terminals in the Kara Sea, can load 2-3 million tons of crude a year. The Barents Sea is one of the most productive oceans worldwide. Few other places on our planet give home to the same amount of breeding seabirds. Here, more than 20 million seabirds from 40 species breed in 1.600 colonies every year. Many of the seabird populations are of mixed Russian-Norwegian origin. In case of an oil spill, the actual amount of oil spilled is not necessarily decisive for the effects on sea bird colonies. The Stylis had a relatively small spill " but 45.000 seabirds were killed. The estimated mortality of the accident was, however, 200.000-300.000 birds. The Amoco Cadiz spilled 223.000 tons of crude oil, but killed 5.000 seabirds. Methods for evaluation of effects on and treatment of birds that have been involved in an oil spill do exist. After the Prestige accident outside Spain, 23.428 seabirds were collected. 5.776 survived. About 1.000 seabirds were released back to nature at a cost of approximately NOK 23.000 (USD 4.100 or EUR 3.000) per bird. The increased development of offshore petroleum fields and increasing sea transport of hydrocarbon products are bound to have a negative effect on the environment. Oil and gas industry developments in the Barents Sea, fisheries, pollution and climate change are the most important treats to the environment in our time. When carrying out impact assessments of activities connected to petroleum activities in this area, one of these factors cannot be evaluated separately, without taking all the other risks into account.
Sammendrag
Det er ikke registrert sammendrag