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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

In this study four Norwegian white clover cultivars were compared with the Danish variety Milkanova under farm site conditions in the different climatic conditions of Norway. A series of field experiments were established with five different white clover cultivars sown in grass mixtures. The swards were defoliated at a sward height of 20 cm to simulate grazing. There were no clear differences in yield production or clover content between the cultivars in the southerly/lowland regions when averaged over three years. Milkanova is a relatively high yielding variety, but has a poor overwintering capacity. The grass/clover mixtures containing Milkanova had the highest yield in the first years of the experiment, but the yields declined and tended to be lower than other cultivars in the third year, with significantly lower clover content. In the alpine/northerly regions, grass/clover mixtures containing Milkanova had lower yield, and lower clover content from the start of the experiment. Both protein, ash and NDF contents were closely linked with white clover content in the swards; with more protein and ash less NDF in plots containing more clover. Feed quality was lower in 3rd cut than in 1st cut.

Sammendrag

Grønnsakdyrking foregår ofte på intensivt dyrkede arealer med tilførsel av store mengder næringsstoffer, noe som gjerne fører til store overskudd i næringsbalansen. Tap av næringsstoffer fra slike arealer er som regel større enn fra øvrige jordbruksarealer. Risiko for avrenning av fosfor er særlig stor på grunn av generell sterk fosforgjødsling og ved at slike åkerkulturer er mer utsatt for jorderosjon, særlig etter høsting i forbindelse med sterke nedbørsepisoder.

Sammendrag

Filter beds and constructed wetlands (CWs) treat municipal wastewater through retention of nutrients and particles. Retention of nitrogen (N) in filter beds was studied in the laboratory using columns and meso-scale trenches filled with shellsand and light-weight aggregates (LWA). The objective was to examine whether measuring the natural abundance of "15N in NO3- could be used to estimate denitrification in these systems. In both the columns and the trenches, it was seen that denitrification was more efficient in shellsand and LWA collected from field scale filter beds compared to raw LWA. This was due to the high pH value (about 10) of raw LWA. The enrichment factors (") from the column study was in general lower than values found in laboratory tests of isotope discrimination in denitrification, but similar to " values found for denitrification in groundwater systems. No enrichment factors could be found for the trench study due to simultaneous denitrification and nitrification. When NH4 was partially nitrified in the upper parts of the trench, this diluted the 15N enrichment of NO3- due to denitrification. Thus in systems with high NH4 concentrations, and partial aerobic conditions, the method of natural abundance is not suitable for estimating denitrification.