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.
2005
Forfattere
Mekjell MelandSammendrag
Kompost frå våtorganisk avfall omdanna i reaktor har vorte prøvd i ulike mengder og modningsgrader i feltforsøk med eple og jordbær ved Planteforsk Ullensvang. Fersk kompost vart lagt i trerekkja i ei stripe på 1 m under epletre i 5, 10 og 15 cm tjukt lag som svarar til om lag 5, 10 og 15 tonn kompost pr. daa. Året etter vart forsøksrutene delte i to og ein halvparten fekk same handsaminga som året føre med ny tilføring av kompost. Eit dekke med 10 cm fersk kompost i frukttrerekkja hemma oppspiring av frøugras i ein vekstsesong. Komposten frigav lite av dei lettløyseleg minerala kalium, fosfor, magnesium og kalsium til jorda første vekstsesongen. Men nitrogenet vart frigjort og teke opp i trea proporsjonalt med mengda av kompost tilført. Ny tilføring av kompost andre året førte til markert auke i jordreaksjonen og dei lettløyselege næringsemna i jorda, men ikkje til auka opptak i plantene. I eit nytt feltforsøk vart ei mengd på 2,8 og 8 tonn kompost pr. daa av både fersk og mogen kompost lagt ut i planterekkja til etablerte epletre av sorten Gravenstein. Fersk kompost verka mest spirehemmande på ugraset første året. Tilføring av ulike kompostmengder påverka lite fruktkvaliteten. Tilføring av størst mengd med kompost frigav lettløyseleg kalium, kalsium og fosfor til jorda og heva pH andre året. Det vart frigjeve lite nitrogen til jorda. Opptaket av ulike næringsemna i trea var lite påverka av ulike mogningsgrader og mengder. I eit feltforsøk med jordbærsorten Korona vart det tilført 5, 10 og 15 tonn pr. daa med fersk og mogen kompost føre planting. Store kompostmengder iblanda i jorda hjå jordbær hemma planteveksten etter planting og jordoverflata og planter vart dekte med soppvekst. Verknad var størst av den ferske og dei største mengdene med kompost. Ulike mengder med fersk og mogen kompost reduserte jordbæravlinga første avlingsåret, men ikkje det andre då avlinga var generelt høg. Bærstorleiken var lite påverka første året, men var større i dei komposthandsama rutene året etter. Begge åra var roteprosenten for høg og då særleg der det var kompost. Det vart ikkje påvist auka opptak av ulike tungmetall i bær som vaks i kompostblanda jord første avlingsåret. Komposten heva pH i jorda og innhaldet av lettløyseleg kalsium, kalium og fosfor i jorda, men lite av magnesium. Nitrogeninnhaldet i jorda var lite påverka verken av modningsgrad og mengder av kompost. Kompost iblanda i jorda førte til at jordbærplantene auka opptaket av nitrogen og kalium, men mindre med fosfor, kalsium og magnesium. Opptaket var proporsjonalt med tilført kompostmengd.
Forfattere
Richard Meadow Linda Hjeljord Annette Folkedal SchjøllSammendrag
In order to infect target insects after application to soil or plant surfaces, Metarhizium anisopliae conidia must remain viable in the face of abiotic and biotic factors. As a part of an inveestigation to develop M. anisopliae as an agent against the black wine weevil, we investigated the fungus ability to compete with conidia of fungi commonly isolated from soil and aboveground surfaces of strawberry in Norway. In previous work, we determined the speed of germination of the isolates at various temperatures, and investigated the effects of inoculating various nutrient substances with conidia of the insect pathogens, before or together with conidia of Cladosporium sp., Trichoderma spp., Verticillium sp., Botrytis cinerea, and Gliocladium sp. Results showed that the insect pathogens, germinated as quickly as the other fungi only at temperatures >=25C. Although germination spees of the insect pathogens varied between isolates, none germinated nor grew as quickly at 15 or 20C as did the other fungi. When coinoculated with conidia of the environmental isolates on a range of agar media at 20C, growth of the insect pathogens was strongly inhibited. In contrast, when the insect pathogens were inoculated at a distance from the other fungi, their colonies inhibited mycelical growth of all the other fungi; M. anisopliae isolates produced clear antibiosis zones against Cladosporium sp. and B. cinerea. On nutrient-poor media, or when substrate nutrients were depleted, colonies of the insect pathogens were eventually overgrown by Gliocladium sp. and Trichoderma spp.In an experiment where weevil larvae were exposed to conidia of M. anisopliae and T. atroviride either separately or combined, and incubated in sterile soil at 22C, the Metarhizium appeared to be unhibited in killing the larvae and sporulating. Follow-up experiments are plannes to look at this interaction at different temperatures and when applying the fungi to the soil.
Sammendrag
Plant production in northern countries is hampered by a short growing season. In Norway, waterpower provides relatively cheap and renewable energy that can be used for artificial lighting. Light is often the limiting factor for plant growth and productivity in greenhouses, and the use of artificial radiation became already early last century an important subject for investigation in Norway. Development of different lamp types gave rise to investigations of light quality on plant performance. Artificial irradiation was primarily confined to plant propagation. Large-scale irradiation of entire crops started in Norway in 1989 and has given rise to a marked increase in winter production of flowers and vegetables. The Norwegian Crop Research Institute performs applied research in all chains of plant production. Research on greenhouse production is coordinated from Særheim Research Centre. Særheim is located in the southwest of Norway where 80% of tomatoes and 50% of the Norwegian cucumbers are produced. Research on the use of artificial light for cucumber production started here in 1990. After that, production systems for lettuce, herbs, strawberry, tomato and sweet pepper were developed. Growers that nowadays use our system for year-round production of cucumbers have increased their yield from 40 to 160 kg/m2. In 2004, we were the first to reach an annual yield of 100 kg/m2 in tomato. In our applied research, consumer and wholesaler demands define the quality aspects of food to be produced. Consumers increasingly demand save and healthy food of high quality. At Særheim Research Centre, effects of environmental conditions (light, temperature, CO2, air humidity, nutrients, growth media) and cultural practices (training, irrigation, harvesting) on size, colour, shelf life, taste and biochemical compounds are being quantified. It could be shown how light intensity and light quality effects the contents of chlorophyll, anthocyanins, ascorbic acid and nitrate in lettuce, shelf life and taste in herbs, taste and antioxidant activity in strawberry, titratable acidity and the contents of phenolics, ascorbic acid, lycopene and soluble solids in tomato. Results will be presented at the workshop. The favourable ratio between light and temperature in our region offers an opportunity to produce high quality products year-round. Norway is known as a healthy country, with little problems with pests and diseases, with an availability of renewable energy, organic growth media and organic fertiliser and with a high water quality. This gives rise to a development of organic production. Research on organic production of greenhouse vegetables started at Særheim in 2003. By now, a rational growing system for organic production of tomato is developed and a system for cucumber production is on trial. Preliminary trials show differences in the content of phenolic compounds, ascorbic acids and antioxidant activity in fruits and plants grown on organic growth media when compared to rockwool. Results will be presented at the workshop.
Forfattere
Marianne BechmannSammendrag
Avrenning av fosfor fra jordbruksarealer har vært et miljøproblem i Norge de siste årtier. Avrenningen er avhengig av faktorer relatert til naturgitte og driftsmessige forhold. Noen arealer kan defineres som kritiske arealer for fosforavrenning. Det gjelder bl.a. arealer med stor erosjonsrisiko, arealer som ligger nær inntil en resipient eller arealer som får eller har fått tilført store mengder fosfor i form av mineral- eller husdyrgjødsel. For å kunne definere kritiske arealer for fosforavrenning, er det i USA utviklet et indekseringsverktøy til bruk på gårdsnivå. Fosforindeksen lister opp faktorer som har betydning for fosforavrenning og beregner en samlet indeks for hvert skifte. Denne fosforindeksen kan brukes av bøndene eller forvaltningen i et nedbørfelt for å prioritere tiltak mot fosforavrenning på arealer med høyest risiko. Avhandlingen omfatter utvikling av en norsk fosforindeks. Den er basert på kunnskap oppnådd gjennom Program for jord- og vannovervåking, vitenskapelige undersøkelser i felt og laboratorieforsøk, samt resultater fra tilgjengelig norsk og internasjonal litteratur. Både kilde- og transportfaktorene er vektet i forhold til betydning for fosforavrenning, og det beregnes en samlet indeks for hvert skifte i nedbørfeltet. En høy fosforindeks betyr at det er stor risiko for fosforavrenning fra et skifte. Avhandlingen omfatter også en vurdering av hvilke data som er tilgjengelige for å estimere de ulike faktorer i fosforindeksen. Det er lagt vekt på at dataene som skal inngå i fosforindeksen er tilgjengelige på skiftenivå for bøndene uten det er nødvendig å gjøre flere undersøkelser. Det er imidlertid behov for forbedringer av datagrunnlaget, spesielt for hydrologiske forhold, blant annet fordelingen mellom overflate- og grøfteavrenning. Fosforindeksen ble utprøvd på nedbørfeltnivå for seks felter på sør-øst landet. Feltene inngår i Program for jord- og vannovervåking. Rangering med fosforindeksen stemte godt overens med de målte verdiene fosfortap for nedbørfeltene (R2=0,79). I etterkant ble fosforindeksen prøvd ut på skiftenivå i et nedbørfelt (Skuterudfeltet) i Akershus. Det ble målt forskjeller i fosforavrenning fra ulike delnedbørfelt. Analyse av de målte konsentrasjoner viste at jordens fosforinnhold har stor betydning for de relative forskjellene i fosforkonsentrasjoner målt i avrenning. Det ble også vist en god sammenheng mellom relative fosforkonsentrasjoner i avrenning fra delnedbørfelt og P indeksen (R2= 0,66). I nedbørfeltforvaltningen er det er behov for et verktøy som kan definere kritiske arealer for fosfortap. Avhandlingen viser at fosforindeks kan brukes som et verktøy i arbeidet med å redusere fosfortapene fra jordbruket.
Forfattere
Astrid Johansen Mats HøglindSammendrag
Verknaden av beitetilbod og kraftfôrtildeling på beiteopptak og mjølkeproduksjon er undersøkt i fire beiteforsøk med mjølkekyr i perioden 2002-2004. Forsøka vart gjennomførte på gras/kvitkløverbeiter (12,9-39,7% kvitkløver) ved Mære landbruksskole, Nord-Trøndelag og Øksnevad landbrukskule, Rogaland. I to av forsøka vart det også gjennomført automatiske registreringar av beiteåtferden. Individuelt beiteopptak vart målt i Forsøk I og II ved hjelp av n-alkanmetoden (Dove & Mayes 1991). Ved å auke beitetilbodet med 6 kg TS frå 12 til 18 kg TS dyr-1 dag-1 auka beiteopptaket mindre enn venta, særleg i Forsøk II (0,6 kg TS dyr-1 dag-1 men også i Forsøk I (1,1 kg TS dyr-1 dag-1). Det var også overraskande at beiteopptaket auka meir ved å auke tilbodet frå 18 til 24 kg TS dyr-1 dag-1, enn frå 12 til 18 kg TS dyr-1 dag-1 i begge forsøka (2,7 og 1,5 kg TS i Forsøk I og II, høvesvis). I Forsøk III og IV vart responsen av beitetilbod og kraftfôrtildeling undersøkt etter eit 2 x 2 faktorielt forsøksdesign. Høgt beitetilbod (18 kg TS dyr-1 dag-1) gav sikkert høgare avdrått (kg mjølk) enn lågt beitetilbod (12 kg TS dyr-1 dag-1) i Forsøk III. Det var også sikker positiv respons på avdråtten av å gje 7 kg Formel 10 samanlikna med 4 kg Formel 10. Verken beitetilbod eller kraftfôrtildeling påverka protein-% i mjølka i Forsøk III, og det vart ikkje funne samspelseffektar mellom beitetilbod og kraftfôrtildeling. Førebelse resultat indikerer at utslaga av både beitetilbod og kraftfôrtildeling var mindre med omsyn til avdråtten i Forsøk IV, samanlikna med Forsøk III. På den andre sida såg det ut til at 8 kg kraftfôr gav høgare innhald av protein og lågare innhald av feitt, samanlikna med frå 4 kg kraftfôr i dette forsøket. Likevel var utbyttet av å gje 7-8 kg kraftfôr samanlikna med 4 kg truleg for lite til at det var økonomisk rekningssvarande i nokon av forsøka. Av innsamla data frå åtferdsregistreringane såg det ut til at dyra på Øksnevad kompenserte kort beitetid med meir effektiv bruk av tida til beiting, samanlikna med dyra på Mære som var ute på beite ein større del av døgnet.
Forfattere
Ricardo Holgado Stig Andersson Christer Magnusson Janet RoweSammendrag
A survey of cereals, carried out in 1995-2005 in Norway, revealed that Heterodera spp. are common throughout the country. Nematodes belonging to the H. avenae complex were recorded from the county of Agder in southern Norway (58.08o N) to the county of Nordland in the north (65.5o N), and this so far is the most northern location reported for Heterodera in cereals. Studies in Norway have recently recorded H. filipjevi and also additional and possibly new species. H. filipjevi is of economic importance in Scandinavia. It was first recorded in the beginning of the 1970s and then referred to as the "Gotland strain of H. avenae". Biotests carried out in Sweden demonstrated the occurrence of two pathotypes, "East" and "West", named according to their geographical distribution. In Norway H. filipjevi, was first recorded causing damage to winter rye, Compared to H. avenae, H. filipjevi has the ability of hatching easily and at low temperatures, this ability of rapid hatch suggests that field population densities could easily be underestimated if based on cyst extractions only. Hence, accurate assessments of pre-plant densities of H. filipjevi require quantification of infective juveniles in soil. Nematode management practices must be based on the knowledge of the population dynamics and the threshold levels needed to cause economic damage. Tests of 63 cereal cultivars on the Norwegian market revealed 13 oat and six barley cultivars to be resistant to H. filipjevi "West" It is important that resistant cultivars of barley are recommended when nematode populations are high, as resistant barley is more tolerant than resistant oats. However even in rotations with resistant barley the farmer should be prepared to accept some yield losses in the first year of management. One important challenge in the management of H. filipjevi is the common occurrence of mixed populations. H. avenae "sensu stricto" and/or its slightly diverging form "Våxtorp" is often found together with H. filipjevi. From our experience the dynamics of mixed populations needs a stronger emphasis in management systems for cereal cyst nematodes. Our knowledge of the occurrence and distribution of cereal cyst nematode species and pathotypes in Norway has increased, and the screening of cultivars for resistance against various populations particularly H. filipjevi, H. avenae "sensu stricto" and the "Våxtorp"-type has been intensified. Hence, today farmers can be provided with control strategies which are easily implemented. With this management system, farmers in the county of Vestfold have increased cereal yields. After 3-4 years of implementation farmers have reported yield increases averaging 1000 kg ha. Compared to the earlier situation (when control was not practiced), a full implementation of the current management program in the county of Vestfold has been estimated to give an annual economic gain in the order of "800 000.
Sammendrag
Various needle discolorations, often due to lack of uptake of certain nutrients are frequently observed in nordmann fir (Abies nordmanniana) in Norwegian Christmas tree plantations. Most common are the yellow to necrotic needle tips on older needles caused by magnesium (Mg) deficiency (confirmed by chemical analysis of foliage). Even though chemical analysis of soil samples show that Mg is present in sufficient amount, various soil factors may cause Mg-deficiency; too high or too low pH, excess potassium (K) or too wet or too dry conditions. Antagonism, causing imbalance in nutrient uptake, can lead to negative effects. High pH may give Ca2+/Mg2+ antagonism, too low pH NH4+/Mg2+ antagonism, and abundant K K+/Mg2+ antagonism. During wet conditions K+ and other monovalent cations may leave the colloids to regain equilibrium between liquid and solid material. Then Mg2+ may easily bind to the free spaces on the colloids, and thereby becomes unavailable for the plants. If the soil is very dry there may not be enough liquid for the nutrients to be dissolved, and thus uptake inhibited. Nordmann fir is mainly grown in the southwestern coastal region of Norway since the climate there is fairly mild and suitable for this plant species. The yearly rainfall is high in that region, so a main cause for Mg deficiency on nordmann fir is probably related to wet soil conditions. Uptake of Mg after foliage application has proved to be ineffective due to the wax layer on the fir needles. However application on young needles and shoots has been reported by the Norwegian extension service to be successful. K deficiency also results in discoloration of older needles, but symptoms can easily be distinguished from Mg deficiency. Both deficiencies results in yellowing of the needles, but different from K deficiency, the base remains green on needles suffering from Mg deficiency. Both Mg and K are very mobile nutrients in plants, and they are therefore easily translocated from older to younger needles. Samples with yellow discoloration of the youngest needles have been observed to be low in iron (Fe) and manganese (Mn), especially when the trees have grown in soil with high pH. Both nutrients are nearly immobile in plants after they have been transported to the cells, and they are therefore not available for the young shoots. Nitrogen (N) deficiency is seen as a uniform, pale green discolouration of both young and old needles.
Sammendrag
In 2004, damages resembling those caused by Phytophthora spp. were observed on three different fir species in Norway. Isolations were carried out from all the host plants on the Phytophthora selective medium PARP (with and without hymexazol added). In a nordmann fir (Abies nordmanniana) Christmas tree field at the southwestern coast of Norway, approximately 70 % of the plants died within a few months after planting. The massive infestation in a field previously used for grass production over decades, left no doubt that the disease had followed the imported transplants. Symptoms included poorly developed roots and discoloration under the bark from the stem basis downwards. The foliage had different stages of drought symptoms; pale green, yellow or brown. Isolations were carried out from the area between healthy and diseased tissue, both from roots and stem base, and a Phytophthora sp. was isolated. The culture produced nonpapillate sporangia with internal proliferation. The sexual stage was observed in water, but not on agar. The oogonia were large. The oospores were aplerotic and the anteridia predominantly amphigynous. ITS rDNA sequences of the isolate were obtained and found to be most similar to P. inundata. Samples were examined from diseased 15-year-old noble fir (A. procera) grown in a bough plantation at the southwestern coast of Norway. Approximately 25 % of the trees were dead or dying. The foliage had turned chlorotic to brown. On one tree a typical stem canker extending approximately 1.5 meters above ground on one side of the tree resulted in dead basal branches (flagging). Isolations were carried out from both roots and the cankered stem. Based on morphological characters (nonpapillate sporangia, internal proliferation, characteristic hyphal swellings, heterothallic culture) and ITS rDNA sequencing, the isolate was identified as P. cambivora. In a Christmas trees planting in southeastern Norway, several seven-year-old trees of subalpine fir (A. lasiocarpa) were dying. The tree loss was estimated to 25 %. Typical Phytophthora canker was found at the base of several trees. Isolations resulted in a culture that readily produced oogonia. The average diameter of the oogonia was 48 "m. The oospores were aplerotic with an average diamerter of 40 "m. The antheridia were paragynous, but a few amphigynous antheridia were also observed. The culture produced nonpapillate sporangia with internal proliferation ITS rDNA sequences matched P. megasperma. A pathogenesis test to fulfil Koch"s postulate was carried out on all three species of fir, each of them inoculated with the respective isolate. After seven weeks, root growth was poor on all the inoculated plants, and canker symptoms had developed in the lower part of the stem. Reisolated culture from noble fir was ITS rDNA sequenced and found identical to the original culture used for inoculation. Results from the ITS rDNA sequencing of the other two reisolated cultures are not yet available.
Forfattere
Marcel van Oijen Mats Høglind Hans Martin Hanslin Nick CaldwellSammendrag
Previously, the literature on the growth of timothy (Phleum pratense L.) in Scandinavia was reviewed and a simple process-based model was developed to explain and predict the response of this species to different environments and management regimes. The model could not be tested in detail, because only biomass data were available at the time. However, recent experimental work has generated a large (n = 633) and uniquely detailed dataset on the growth and underlying physiology of timothy and its response to cutting at different growth stages. The present study aimed to use this dataset to test the model, and to use the model to identify the key physiological and morphological mechanisms that determine the regrowth rate of timothy after cutting. Model testing consisted of comparing simulations and measurements for eight variables: biomass, leaf area index (LAI), tiller and leaf density, rates of leaf appearance and elongation, carbohydrate concentration, and specific leaf area. Although the new data referred to a different cultivar, a different site, and different years from those used in the original model parameterization, the model was still able to account for nearly half the variation in the dataset [r2 = 0.468, normalized root mean squared error (RMSE) = 0.631]. This suggested that the key assumptions of the model (i.e., dependence of growth and allocation on the source-sink balance of the plants and a dose link between tillering and leaf area dynamics were plausible. However, the original model was not able to account for the observation that cutting at early heading tended to be followed by a longer lag phase than cutting at anthesis. We identified six mechanisms, not previously incorporated in the model, that improved its behavior: (1, 2) dependence of tillering and leaf appearance rate on carbohydrate concentration, (3, 4) dependence of leaf appearance and leaf elongation rate on plant phenological stage, (5) sprouting of new tillers from decapitated generative tillers, and (6) proportionality of the number of elongating leaves with tiller size. Incorporation of these mechanisms, followed by reparameterization using a Metropolis-Hastings Monte Carlo method, improved performance statistics (r2 = 0.521, normalized RMSE = 0.415) and explained the long duratjon of slow growth after early cutting. These mechanisms may thus be keys to understanding timothy regrowth.
Forfattere
Tor Håkon SivertsenSammendrag
Some general ideas for classifying phenomena connected to weather and climate are presented, and a few well known systems for classification of meteorological phenomena are then shortly discussed, like the classification system of clouds constructed by Luke Howard in the beginning of the 19th century and the much later system connected to synoptic charts and synoptic meteorology etc.. The classification system of climate, developed by Wladimir Köppen is shortly discussed. Then the definition of `meteorological element" and `climatic element" according to the `International Meteorological Vocabulary" of WMO are presented and discussed, and the concepts of `parameter" and `parameterisation" are presented and defined somewhat broader than according to the `International Meteorological Vocabulary". The CREX (Character form for the Representation and EXchange of data) and BUFR (Binary Universal Form for Representation of meteorological data) as well as the GRIB (`GRIdded Binary" systems for exchange of data are presented. The message according to this discussion is that the meta data part of the BUFR and CREX-systems ( despite the great flexibility and scope of these systems) ought to be considered revised according to some of the principles of this discussion on classification of phenomena, and the parameterisation of the phenomena. It is important to make clear and communicated to the public what is the additional gain of using satellite data, and to what measure ground based station network may be replaced. Especially one ought to tell the public that all remote sensing equipment ought to be calibrated continuously by reference to a station network. Also the very important work on `homogenisation" of long data series of meteorological data is connected to the observing systems. In studies on global change and climate change it is important to be able to refer to long homogenous series of meteorological data. The conclusion is very short: When looking at the systems for classification, documentation and exchanging meteorological data, what could be considered is making some sort of parallel work of extending the biological and agro meteorological models to use the BUFR and GRIB-protocols, but at the same time take a look at the metadata systems of GRIB and BUFR first to see if the classification systems may be constructed in a more logical way using methods from object oriented analysis of the modern IT-world?