Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2016
Abstract
Norway spruce (Picea abies (L.) Karst.) understory seedlings, growing in partially harvested plots with different canopy cover in a boreal spruce stand, were spot fertilized (Hydro 15-4-12) 9 years after planting. The principal aimwasto test the hypothesis that nitrogen (N)availability influences growthof understory seedlings at intermediate but not at lowlevels of irradiance. In addition, we tested the combined influences of N and light availability on selected morphological and phenological traits, covering a 2-year period after treatment. Diffuse radiation (DIFR) at the seedling level was estimated from hemispherical photographs and ranged from 19 to 46 per cent of DIFR in openconditions. Fertilizer applicationwasassociatedwithamarkedincreasein foliarNconcentration.Thefertilized seedlings grew better in height and root collar diameter compared with unfertilized controls. While the absolute growth in both diameterand height increased with increasing DIFR, seedlings also responded to improved nutrient availability across the rangeof light conditions studied. Fertilizer treatment did not affect thenumberof nodal buds, but we observed a higher apical dominance ratio and advanced bud burst in fertilized seedlings. In conclusion, nutrient availability influenced growth and bud phenology of understory Norway spruce seedlings at least down to 20 per cent DIFR.
Abstract
Feeding by pine weevil (Hylobius abietis L.) causes severe damage to newly planted conifer seedlings in most parts of Scandinavia. We investigated the effect of planting time and insecticide treatment on pine weevil damage and seedling growth. The main objective was to study if planting in early autumn on fresh clear-cuts would promote seedling establishment and reduce the amount of damage caused by pine weevil the following season. The experiment was conducted in southern Sweden and in south-eastern Norway with an identical experimental design at three sites in each country. On each site, Norway spruce seedlings with or without insecticide treatment were planted at four different planting times: August, September, November and May the following year. In Sweden, the proportion of untreated seedlings that were killed by pine weevils was reduced when seedlings were planted at the earliest time (August/September) compared to late planting in November, or May the following year. This pattern was not found in Norway. The average length of leading shoot, diameter growth and biomass were clearly benefited by planting in August in both countries. Insecticide treatment decreased the number of seedlings killed or severely damaged in both Norway and Sweden.
Authors
Johannes BreidenbachAbstract
No abstract has been registered
Abstract
Berry yield and chemical composition of four commercial black currant cultivars were recorded in a field experiment in Norway over an 8-year period and related by linear regression analysis to temperature and precipitation conditions prevailing during the May-July preharvest period. Highly significant differences between cultivars and among years were found for all measured parameters. Fruit dry matter, soluble solids and pH were positively correlated with temperature and negatively correlated with precipitation during May-July, while yield, berry weight, and the concentration of total phenols and ascorbic acid showed the opposite relationship, being highly negatively correlated with temperature and positively correlated with precipitation. Similar black currant experiments elsewhere in Europe have often given deviating results, varying from opposite to no effects of the same weather variables, suggesting that fruit composition is influenced by several interacting genetic and environmental parameters. We conclude that differences in local weather and soil conditions and the use of different cultivars complicate direct comparison of such field experiments. Nevertheless, the observed strong and opposite correlations with precipitation and temperature suggest an inherently low drought tolerance of black currant plants.
Abstract
Effects of three different pasture allocation techniques on milk yield and quality with mid-lactation dairy cows
Abstract
We assessed milk production with 24 mid-lactation Norwegian Red dairy cows on a spring pasture dominated by timothy (Phleum pratense) for a period of 21 days using three pasture allocation techniques (n=8). Cows received weekly allowances at once (7 day-set-paddocking; 7SP), grazed 1/7 of 7SP allowance each day (daily-strip-grazing; 1SG), or grazed like 1SG but also had access to the previously grazed part of the paddock (daily-forward-grazing; 1FG). We hypothesized that 7SP would deteriorate sward quality and quantity over the grazing days whilst the other two treatments would provide balanced pasture quality and intake. These changes were expected to result in differences in milk yield and its components. However, changes in sward chemical composition (e.g. neutral netergent fiber, crude protein) over the grazing days in each week were not different among treatments (treatment × grazing day; P>0.05). Furthermore, no effect of treatments on milk yield and its components was observed. Nonetheless, the effects of grazing days over a week on milk yield and components were different among treatments (treatment × grazing day; P<0.05). These treatment by grazing day interaction effects, in the absence main effect of treatment, could be due to fluctuations in daily DMI among treatments over the grazing days in each week.
Abstract
We assessed milk production with 24 mid-lactation Norwegian Red dairy cows on a spring pasture dominated by timothy (Phleum pratense) for a period of 21 days using three pasture allocation techniques (n=8). Cows received weekly allowances at once (7 day-set-paddocking; 7SP), grazed 1/7 of 7SP allowance each day (daily-strip-grazing; 1SG), or grazed like 1SG but also had access to the previously grazed part of the paddock (daily-forward-grazing; 1FG). We hypothesized that 7SP would deteriorate sward quality and quantity over the grazing days whilst the other two treatments would provide balanced pasture quality and intake. These changes were expected to result in differences in milk yield and its components. However, changes in sward chemical composition (e.g. neutral netergent fiber, crude protein) over the grazing days in each week were not different among treatments (treatment × grazing day; P>0.05). Furthermore, no effect of treatments on milk yield and its components was observed. Nonetheless, the effects of grazing days over a week on milk yield and components were different among treatments (treatment × grazing day; P<0.05). These treatment by grazing day interaction effects, in the absence main effect of treatment, could be due to fluctuations in daily DMI among treatments over the grazing days in each week.
Abstract
No abstract has been registered
Abstract
A future wetter climate in Northern Europe may increase soil compaction from traffic of heavy machinery. This study investigated the impact of tractor traffic on grassland yield, soil physical properties and penetration resistance in three experimental field trials in Norway; on medium sand at Tjøtta, Nordland, on silty medium sand at Fureneset, Sogn og Fjordane and on silt at Løken, Oppland. The experiments were conducted in a split-plot design with three levels of two wheel-by-wheel passes with tractor traffic after each cut: no traffic, light tractor or heavy tractor on large plots, and three different seed mixtures on small plots. The yield reduction by tractor traffic was 26% at Løken, 4% at Fureneset and 1% at Tjøtta. There was a positive correlation between soil moisture content and yield reduction by traffic. Tractor traffic reduced pore volume and air capacity and increased bulk density, compaction degree and penetration resistance with the largest effect at Løken and the smallest at Tjøtta. There were no statistically significant differences in yield or soil physical properties between light and heavy tractor. The study shows that soil texture and soil moisture content are major factors explaining traffic effects on soil physical properties and grassland yield.
Abstract
This study examined the P fertilization effects of 11 sewage sludges obtained from sewage treated with Al and/or Fe salts to remove P by a pot experiment with ryegrass (Lolium multiflorum) and a nutrient-deficient sand−peat mixture. Also it investigated whether fertilization effects could be predicted by chemical sludge characteristics and/or by P extraction. The mineral fertilizer equivalent (MFE) value varied significantly but was low for all sludges. MFE was best predicted by a negative correlation with ox-Al and ox-Fe in sludge, or by a positive correlation with P extracted with 2% citric acid. Ox-Al had a greater negative impact on MFE than ox-Fe, indicating that Fe salts are preferable as a coagulant when aiming to increase the plant availability of P in sludge. The results also indicate that sludge liming after chemical wastewater treatment with Al and/or Fe salts increases the P fertilization effect.