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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.

2023

Sammendrag

Appropriate weed control measures during the renewal phase of temporary grasslands are critical to ensure high yields during the whole grassland lifecycle. The aim of this study was to determine which integrated grassland renewal strategy can most effectively control annual weeds in the sowing year and delay perennial weed re-establishment. Four split-plot trials were established at three sites dominated by Rumex spp. along a south-north gradient in Norway. The annual and perennial weed abundance was recorded during the sowing year and two or three production years. Main plots tested seven renewal strategies: 1. Spring plowing, 2. Spring plowing+companion crop (CC), 3. Summer cut+plowing, 4. Summer glyphosate+plowing, 5. Summer glyphosate+harrowing, 6. Late spring glyphosate+plowing, 7. Fall glyphosate+spring plowing+CC. Strategies 1–4 were tested in all four trials, strategy 5 in three trials, strategy 6 in two trials and strategy 7 in one trial. Plowing was performed at 20–25 cm depth, rotary harrowing at 15 cm depth, and glyphosate was applied at 2160 g a.i. ha-1. CC was spring barley (Hordeum vulgare). Subplots tested selective herbicide spraying (yes/no) in the sowing year. Results showed that effects of renewal strategies were often site-specific and differed between the sowing year and production years. Spring renewal resulted in higher perennial weed abundance than summer renewal in two out of four trials (by 3 and 12 percentage points, over all production years), and glyphosate followed by harrowing drastically increased Rumex spp. in one out of three trials (by 18 percentage points over all production years). CCs only significantly reduced perennial weed abundance in one trial (by 8 percentage points over all production years). In comparison, the selective herbicides had a strong effect on annual and perennial weeds in the sowing year in all trials. Selective herbicides reduced the weed cover from 32% to 7% cover, and averaged over the production years and sites, the perennial weed biomass fraction was 6 percentage points lower where herbicides had been applied. We conclude that while the tested renewal strategies provided variable and site-specific perennial weed control, selective herbicides were effective at controlling Rumex spp. and other perennial dicot weeds in the first two production years.

Til dokument

Sammendrag

To compensate for higher production costs in winter, tomato cultivars with better taste and flavor characteristics and higher selling price are often cultivated. Tomato taste and flavor is reduced during cold storage, however the reduction is often cultivar dependent. Little is known how postharvest storage conditions affect flavor and taste quality of tomatoes cultivated in greenhouses during wintertime at high latitudes. This study was aimed to analyze how postharvest storage conditions affect composition of flavor-related volatile organic compounds (VOCs) and taste quality of tomato fruits. Tomato cultivars ‘Brioso’, ‘Flavance’, ‘Piccolo’, ‘Sweetelle’, ‘Sweeterno’ were grown in greenhouses with artificial lightning in southwestern Norway during wintertime and were collected ripe. Experimental set up was simulating shortest postharvest chain for southwestern Norway, including harvest day (18°C for one day, in darkness), packaging and transport (12°C for 3 days, in darkness), retail (18°C for 2 days, with light) and consumer storage in either a refrigerator (4°C for 4 days, in darkness) or a kitchen counter (20°C for 4 days, with light). VOC composition of tomato fruits was analyzed using HS-SPME-GC-MS. Fruit quality parameters including sugars, titratable acidity (TA), dry matter content, firmness and pigments were analyzed. Laboratory results were compared to responses from a taste panel. Firmness and TA were lower for fruits after storage at both conditions compared to fresh fruits. Relative concentrations of the most flavor-related VOCs were lowest for fruits after storage at both conditions. The reduction was higher when fruits were stored at 4°C. Fruits from cultivars ‘Sweeterno’ and ‘Piccolo’ showed the lowest difference in relative VOC concentration at 4°C. Perceived overall tomato taste generally decreased after storage. Overall, storage at 20°C is favorable for preserving flavor of most winter-produced tomato cultivars, but disadvantageous for maintaining their firmness and TA.

Til dokument

Sammendrag

The effects of tree pollen on precipitation chemistry are not fully understood and this can lead to misinterpretations of element deposition in European forests. We investigated the relationship between forest throughfall (TF) element fluxes and the Seasonal Pollen Integral (SPIn) using linear mixed-effects modelling (LME). TF was measured in 1990–2018 during the main pollen season (MPS, arbitrary two months) in 61 managed, mostly pure, even-aged Fagus, Quercus, Pinus, and Picea stands which are part of the ICP Forests Level II network. The SPIn for the dominant tree genus was observed at 56 aerobiological monitoring stations in nearby cities. The net contribution of pollen was estimated as the TF flux in the MPS minus the fluxes in the preceding and succeeding months. In stands of Fagus and Picea, two genera that do not form large amounts of flowers every year, TF fluxes of potassium (K+), ammonium-nitrogen (NH4+-N), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) showed a positive relationship with SPIn. However- for Fagus- a negative relationship was found between TF nitrate-nitrogen (NO3−-N) fluxes and SPIn. For Quercus and Pinus, two genera producing many flowers each year, SPIn displayed limited variability and no clear association with TF element fluxes. Overall, pollen contributed on average 4.1–10.6% of the annual TF fluxes of K+ > DOC > DON > NH4+-N with the highest contribution in Quercus > Fagus > Pinus > Picea stands. Tree pollen appears to affect TF inorganic nitrogen fluxes both qualitatively and quantitatively, acting as a source of NH4+-N and a sink of NO3−-N. Pollen appears to play a more complex role in nutrient cycling than previously thought.

Sammendrag

Sandjord har lite kationebytekapasitet og lite lagerkapasitet for næringsstoff som kalium. Kalium er mellom anna viktig i innvintringa, og ei ekstra kalium-gjødsling om hausten kan derfor i teorien hjelpe enga å klare seg gjennom vinteren. Dersom me gjødsla med 6 kg ekstra kalium ut over gjødselplan, anten før eller etter sisteslått, fekk me ikkje sikker meiravling i førsteslåtten til 13 feltforsøk på sandjord med låg syreløyseleg kalium. Me har ikkje funne effekt av kaliumgjødsel til eng på sandjord seint i sesongen. Årsaka til dette resultatet botnar truleg i at kaliumforsyninga til engvekstane har vore tilstrekkeleg med gjødsling etter gjødselplanen.