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.
2000
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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Sammendrag
A new white clover cultivar, Norstar, with excellent winter hardiness and good yield potential has been released (1999) for northern and upland parts of Norway. In a field experiment in Tromsø (690 39"N), the dry matter (DM) yield and persistence of Norstar in mixtures with different grass species was studied. The plots were subjected to simulated grazing or cut for silage, and fertilised with a yearly total of 60kg Nha-1. DM yields of the clover and grass components were determined during three growing seasons. The different grass mixtures had no direct impact on DM yield of clover, but in the first year the clover proportion of the total grass/clover yield was lower in mixture with timothy/meadow fescue than in mixture with smooth meadowgrass. However, in the following years the clover proportion of this mixture increased, whereas it declined in the mixture containing smooth meadowgrass. In 1999, the clover content in both mixtures was about 30%. Cutting regime had no influence on clover yield in either of the mixtures. Simulated grazing depressed the grass yield in white clover/timothy/meadow fescue mixtures, but not in white clover/smooth meadowgrass mixtures.
Sammendrag
In the present study, the growth, dry matter partitioning and morphological characteristics and C exudation of two white clover cultivars, Norstar and AberHerald, were compared, under two temperature regimes (24/18°C and 12/6°C day/night) in a controlled temperature room. Root exudates collected from the two cultivars were also tested on two common soil types from northern Norway to determine the influence of the exudates on microbial activity in those soils. Plants grown at the higher temperatures had greater biomass and lower root:shoot ratio than those grown at the lower temperature regime. The plants growing in the higher temperature regime had a higher N content and concentration. Temperature significantly affected morphological characters and plants grown at the higher temperature had more leaves and growing points, and longer stolons than those grown at 12/6°C. Total organic C in the root exudates was determined on two occasions during the experiment. After 7 days, the concentration in the leachates from the plants at the higher temperature was significantly greater, but after 34 days, the concentrations were much more variable from plant to plant and no significant differences were seen. There were no significant differences in the rate of O2 uptake and utilisation by either the peat or mineral soils given exudates collected from plants growing at the cooler temperatures. In soils which were given exudates collected from plants growing at the higher temperatures, the rate of O2 utilisation by the mineral soil given the Norstar exudates was significantly lower than the other three combinations.
Sammendrag
Transfer of nitrogen from clover to grass can be an important component in nutrient cycling, especially in poor soils. Plant root exudates are an important source of carbon and nitrogen in the rhizosphere and may actively contribute to grass growth and nutrient uptake. It has been shown that nitrate and ammonium uptake by white clover can be influenced by temperature, but little work has been done to determine the effect of temperature on substrate release from white clover roots and subsequent effects on grasses. Stresses imposed on clover plants may change the form and quantity of root exudation and will effect the general carbon and nitrogen economy of white clover. The ways in which temperature stress affects nutrient uptake and root exudation of clover and ryegrass were studied in this project.
Sammendrag
Kalver i alderen 9-12 mnd har samme tilvekst om de fores med kraftfor eller egenprodusert valset bygg. Det er usikkert om bedre valsing ville gitt enda bedre tilvekst. Det er videre usikkert om resultatene ville vært de samme dersom forsøket strakk seg over lenger tid. Det er god lønnsomhet å fore med egetprodusert valset bygg i stedet for innkjøpt kraftfor dersom bonden fra før har det nødvendige driftsutstyr.
Sammendrag
Dyrking av kløver som underkultur bidrar positivt til nitrogenbalansen på økologiske korngårder fordi nitrogen samles fra luft også i år med korn som hovedgrøde. Inntil videre har vi anbefalt å bruke Milkanova kvitkløver som underkultur, og at denne såes tidlig (samtidig med kornet eller ved første ugrasharving; Økologisk Landbruk nr. 1 og 2, 2000). Men hvor stor gjødselvirkning har egentlig en kløver underkultur på etterfølgende korn? I dette arbeidet fant vi at en kløver underkultur gir 50 kg økning i kornavlingene året etter og at vi må finne metoder for å øke utnyttelsen av kløver-nitrogenet.
Sammendrag
ttårige kvitkløversorter samler mer nitrogen i underkulturåret enn flerårige sorter. Sorten Milkanova anbefales brukt som underkultur ved økologisk korndyrking dersom målet er størst mulig nitrogensamling. Innsåing av kvitkløver i korn gir ingen vesentlig avlingsreduksjon i underkulturåret, fører ikke til utsatt tresking og øker hektolitervekta.
Forfattere
Hugh RileySammendrag
Tidligpoteter blir i Norge ofte gjødslet med større N-mengder enn det som brukes til sein potet. Dette er en praksis som medfører stor risiko for N-tap til miljøet og som kan gi nypoteter med lavt tørrstoffinnhold. Resultatene som er presentert her gir grunnlag for å redusere N-gjødselmengden, og viser at delt gjødsling til tidligpotet er unødvendig. Strategier drøftes for å ta hånd om restmengdene av nitrogen i jorda etter høsting.