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
Janneche Utne Skåre Jan Alexander Augustine Arukwe Trine Eggen Gunnar Sundstøl Eriksen Christiane Kruse Fæste Kari Grave Helle Katrine Knutsen Amund Måge Anders RuusSammendrag
Det er ikke registrert sammendrag
Forfattere
Roald AasenSammendrag
Fra vaskevannet til røygassrenseanleggene på forbrenningsanleggene Brobekk og Klemetsrud i Oslo ble det tatt prøver hver dag fra mandag til søndag i uke 9, 2007 for bestemmelse av prosessvannets hemmende virking på nitrifisering hos mikroorganismer i aktivt slam fra renseanlegg for avløpsvann etter NS-EN ISO 9509 standarden. Aritmetisk middelverdi av prøvene viste at 50 % hemning (EC50) oppstod ved 11±2 mg prøve/l for prosessvann fra Brobekk og 10±3 mg prøve/l for prosessvann fra Klemetsrud forbrenningsanlegg. Prøvene viste at graden av hemming for uke 9 i 2007er innenfor de anbefalte kravene for hemming av nitrifisering ved påslipp til kommunalt ledningsnett.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Ingunn Molund Vågen Trygve Aamlid Arne Oddvar SkjelvågSammendrag
The effects of three nitrogen (N) fertilizer rates (0, 120, and 240 kg N ha(-1)) and two planting times (May or late June/July) on yield and N use of the early cultivar 'Milady' and the late cultivar 'Marathon' of broccoli (Brassica oleracea var. italica) were investigated on three silty loam soils varying in soil mineral N (Nmin) in the southernmost part of Norway during 1999 and 2001. In all crops receiving fertilizer, rapid uptake of N started about three weeks after planting. The relative yield of broccoli heads increased with increasing soil available N (fertilizer N plus Nmin) at planting to 200-250 kg N ha(-1) and then levelled off. The two lower fertilizer rates were more restrictive to yields in early-planted than in late-planted crops. A general increase in harvest index with increasing N rate reflected a stronger effect of N on the head yield than on the total above ground biomass production. The apparent recovery of fertilizer N decreased with increasing N rate and was on average 74% in total above ground biomass and 25% in broccoli heads. Despite a higher N uptake, the average soil mineral N level at harvest increased from 12 kg N ha(-1) on unfertilized plots to 27 and 78 kg N ha(-1) on plots receiving 120 and 240 kg N ha(-1), respectively; this increase was stronger in early than in late plantings and stronger in 'Milady' than in 'Marathon'. The yield of broccoli heads was similar in the two cultivars, but 'Milady' had a lower total biomass production and thus a higher harvest index, presumably due to earlier head initiation.
Forfattere
Anne Kristine Søvik P.T. MørkvedSammendrag
Constructed wetlands (CWs) treat municipal wastewater through the retention of nutrients and particles. The retention of nitrogen (N) 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 d15N in NO2 3 could be used to estimate the relative contribution of denitrification to the total NO2 3 removal in these treatment systems. In both the columns and the trenches it was seen that denitrification was more efficient in shellsand and LWA collected from on-site treatment systems compared to new LWA. This was due to the high pH value (about 10) of new LWA. The enrichment factors (e ) from the column study were in general lower than values found in laboratory tests of isotope discrimination in denitrification, but similar to e values found for denitrification in groundwater systems. No enrichment factors could be found for the trench study due to simultaneous denitrification and nitrification and inhomogeneous N transformation patterns. When NHþ4 was partially nitrified in the upper parts of the trench, this diluted the 15N enrichment of NO2 3 due to denitrification. Thus, in systems with high NHþ4 concentrations and partial aerobic conditions, the method of natural abundance is not suitable for estimating the relative contribution of denitrification to the total NO2 3 removal.
Forfattere
Trygve S. Aamlid Gunvald Henning JonassenSammendrag
Field trials comparing various combinations of 0, 30 or 60 kg N ha-1 in autumn (September) and/or spring (April) to seed crops of common bent (syn. browntop, US: colonial bentgrass, Agrostis capillaris L.) "Leikvin" (main use: long-lasting pastures and utility turf) and "Nor" (main use: lawns and golf course fairways) were carried out on silt loam soils at Landvik, south-east Norway (58°N) from 1989 to 1994. One trial per cultivar was established in 1989, 1990 and 1991, each trial being harvested for three years. On average, for nine harvests and nine N treatments, "Leikvin" and "Nor" gave seed yields of 276 and 128 kg ha-1, respectively. Seed yields of "Leikvin" increased with increasing N rate up to 60 kg N ha-1 in autumn and 30 kg N ha-1 in spring; no interaction between autumn and spring N rate could be detected in this cultivar. In "Nor", a significant autumn x spring rate interaction indicated a linear seed yield response to N in spring on plots that had received 60 kg N ha-1 in autumn, but a diminishing response to N in spring on plots that had received 0 or 30 kg N ha-1 in autumn; the highest seed yield was produced with autumn + spring applications of 60 + 60 kg N ha-1 in this lawn cultivar. While panicle number and seed number per panicle were equally important for seed yield in "Leikvin", panicle number had the stronger impact on seed yield in"Nor". Seed crops of "Leikvin" were generally taller and more susceptible to lodging than seed crops of "Nor". Year-to-year variations in seed yield level and optimal N regime were less related to crop age than to weather conditions and seed crop management. Given the present prices for fertilizer and seed, it is concluded that Norwegian seed crops of common bent should receive 50-60 kg N ha-1 in autumn regardless of cultivar. Economically optimal N rates in spring are 30 and 60 kg N ha-1 to "Leikvin" and "Nor", respectively.
Forfattere
Anne-Grete Buseth Blankenberg Ketil Haarstad Anne-Kristine SøvikSammendrag
Agricultural runoff contributes with significant amounts of nitrogen (N) to rivers and lakes causing water quality problems. Constructed wetlands (CWs) in first- and second order streams reduce downstream loading of nutrients through mechanisms such as sedimentation, uptake by vegetation and microbial denitrification. (A stream with no tributaries (headwater stream) is considered a first order stream. A segment downstream of the confluence of two first order streams is a second order stream [1]). Norwegian CWs are often too small to easily achieve high N-retention. It is therefore important to improve and optimize the N-retention processes in the CWs where the CW area cannot be increased due to local restrictions. The main aim of this project was to compare N-retention in an experimental wetland including eight different types of organic and mineral CW-filters, one of which was a standard Norwegian CW (depth 0.5 m). The average total-N retention through the experimental wetland was 17 % for the period of May-September in 2003, but only 2% in the same period in 2004. Converted to mass, the retention in 2003 was 168 kg and 26 kg in 2004. Lower retention in 2004 was probably mainly caused by higher hydraulic load that year. The organic filters performed better than the mineral filters and the standard CW.
Forfattere
Tor Lunnan Anne Kjersti BakkenSammendrag
I forsøk i Valdres, Stjørdal og på Ås har ein sett på korleis forholdet mellom N og S i grovfôret blir påverka av om tilført mineralgjødsel inneheld S eller ikkje. I Valdres var det liten verknad av gjødseltype på avlingsmengde og -kvalitet. Dei to andre plassane vart avlingane større og forholdet mellom N og S betre i høve til normene for drøvtyggarfôr dersom S vart tilført. I ein annan serie såg ein på korleis forholdet mellom N og S varierte mellom førsteslåttar tatt til ulike utviklingstrinn. Der det var lite kløver i avlinga, gjekk N/S-forholdet ned med stigande utviklingstrinn sjølv om det vart gjødsla med svovelhaldig Fullgjødsel. Raudkløveren såg ut til å ha for lite S i høve til N om ein held seg til amerikanske og britiske normer for fôring.
Forfattere
Anne Kristine SøvikSammendrag
De biologiske prosessene som fjerner nitrogen og karbon i naturbaserte rensesystemer som konstruerte våtmarker og filterbedanlegg kan også produsere drivhusgassene lystgass (N2O) og metan (CH4). Målinger av gassflukser i felt ved ulike årstider har gitt oss en indikasjon på mengden av disse gassene som slipper ut fra ulike typer naturbaserte renseanlegg. Laboratorieforsøk har bedret forståelsen av faktorer som påvirker produksjon av N2O i ulike typer filtermaterialer brukt i naturbaserte rensesystemer.
Forfattere
Anne Kristine SøvikSammendrag
De biologiske prosessene som fjerner nitrogen og karbon i naturbaserte rensesystemer som konstruerte våtmarker og filterbedanlegg kan også produsere drivhusgassene lystgass (N2O) og metan (CH4). Målinger av gassflukser i felt ved ulike årstider har gitt oss en indikasjon på mengden av disse gassene som slipper ut fra ulike typer naturbaserte renseanlegg. Laboratorieforsøk har bedret forståelsen av faktorer som påvirker produksjon av N2O i ulike typer filtermaterialer brukt i naturbaserte rensesystemer.