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.
2009
Forfattere
Holger Lange Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hansen Tonje Økland Ingvald Røsberg Trine Aulstad Sogn Volkmar TimmermannSammendrag
Det er ikke registrert sammendrag
Forfattere
Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hanssen Holger Lange Tonje Økland Ingvald Røsberg Trine Aulstad Sogn Volkmar TimmermannSammendrag
In Norway, it is planned to double the stationary use of bioenergy from all sources by up to 14 TWh before 2020, with much of this increase coming from forest resources, including residues like branches and tops (which are not much used today) being removed after tree harvest. This removal will reduce the supply of nutrients and organic matter to the forest soil, and may in the longer term increase the risk for future nutrient imbalance, reduced forest production, and changes in biodiversity and ground vegetation species composition. However, field experiments have found contrasting results (e.g. Johnson and Curtis 2001; Olsson et al. 1996). Soil effects of increased biomass removal will be closely related to soil organic matter (SOM) dynamics, litter quality, and turnover rates. The SOM pool is derived from a balance between above- and below-ground input of plant material and decomposition of both plants and SOM. Harvest intensity may affect the decomposition of existing SOM as well as the build-up of new SOM from litter and forest residues, by changing factors like soil temperature and moisture as well as amount and type of litter input. Changes in input of litter with different nutrient concentrations and decomposition patterns along with changes in SOM decomposition will affect the total storage of carbon, nitrogen and other vital nutrients in the soil. To quantify how different harvesting regimes lead to different C addition to soil, and to determine which factors have the greatest effect on decomposition of SOM under different environmental conditions, two Norway spruce forest systems will be investigated in the context of a research project starting in 2008/2009, one in eastern and one in western Norway, representing different climatic and landscape types. At each location, two treatment regimes will be tested: Conventional harvesting, with residues left on-site (CH) Aboveground whole-tree harvest, with branches, needles, and tops removed (WTH). Input of different forest residues will be quantified post harvest. Soil water at 30 cm soil depth will be analysed for nutrients and element fluxes will be estimated to provide information about nutrient leaching. Soil respiration will be measured, along with lab decomposition studies under different temperature and moisture regimes. Long term in situ decomposition studies will be carried out in the WTH plots using three different tree compartments (needles, coarse twigs, fine roots) decomposing in litter bags, in order to determine their limit value. The structure of the fungal community will be determined by soil core sampling and use of molecular techniques allowing qualitative and quantitative estimation. Understorey vegetation will be sampled to determine the biomass, and the frequency of all vascular plants, bryophytes and lichens will be estimated. After harvesting, replanting will be carried out. Seedling survival, causes of mortality and potential damage, growth, and needle nutrients will be monitored. Results from these studies will be used to identify key processes explaining trends observed in two series of ongoing long-term whole-tree thinning trials. We shall combine knowledge obtained using field experiments with results of modelling and data from the Norwegian Monitoring Programme for Forest Damage and National Forest Inventory. This will help us to predict and map the ecologically most suitable areas for increased harvesting of branches and tops on a regional scale based on current knowledge, and to identify uncertainties and additional knowledge needed to improve current predictions.
Forfattere
Hege Nordheim-Viken Harald Volden Marit JørgensenSammendrag
The aim of this experiment was to investigate effects of temperature and photoperiod on growth characteristics, chemical composition and indigestible fibre (IaNDF) in timothy harvested at three defined maturity stages. Two cultivars of timothy, Engmo (69 degrees N) and Grindstad (59 degrees N) were grown in a controlled environment using a phytotron, and were exposed to two different temperature regimes (21/15 degrees C and 15/9 degrees C, 12h/12h)and photoperiods (18 and 24h). Plants were harvested at beginning of heading (BH), full heading (FH) and anthesis (AN). Leaves and stems were separated prior to chemical analyses and ruminal in situ incubation for 288 h was used to determine indigestible aNDF (IaNDF) content. Plants grown at low temperature used almost twice the number of days to reach AN, compared to the highest temperature regime. This explained the lower leaf:stem ratio (LSR), higher aNDF content and lower crude protein (CP) content in low temperature plants. The effect of temperature was often dependent on maturity stage. However, the content of IaNDF and lignin(sa) was only affected by maturity stage at harvest. The content of IaNDF and lignin increased by 70% and 35% respectively from BH to AN. The lack of response in IaNDF and lignin(sa) content and dry matter digestibility to temperature was probably caused by a combination of direct and indirect temperature effects. Photoperiod affected growth characteristics, but had minor effects on chemical composition and IaNDF. Due to the lower LSR, Engmo had higher IaNDF and lignin(sa) content than Grindstad. This study showed a high positive correlation (0.93) between IaNDF and lignin(sa). Interactions between temperature and maturity stage affect the growth and nutritive characteristics of timothy. However, only maturity stage affected IaNDF and lignin(sa) content. (C) 2009 Elsevier B.V. All rights reserved.
Sammendrag
Growth and flowering of the annual-fruiting raspberry (Rubus idaeus L.) cultivar 'Polka' were studied under controlled environment conditions in order to facilitate out-of-season production. Vegetatively-propagated plants originating from adventitious root buds were used. Height growth and the rate of leaf formation increased with increasing temperature, up to a broad optimum in the mid-20 degrees C range. While elongation was consistently enhanced by long-day (LD) conditions, photoperiod had no effect on the rate of leaf formation. LD stimulation of growth thus resulted from increased internode length only. In agreement with earlier reports, it was found that, in contrast to biennial-fruiting cultivars, such annual-fruiting cultivars do not need low temperatures for flower initiation, nor do they appear to have a juvenile phase during which they are un-responsive to flower-inducing conditions. 'Polka' plants responded to inductive conditions as early as the 5-leaf stage, and flowered freely across the entire range of growth temperatures, even at 30 degrees C. Flowering was advanced and the number of flowers increased with increasing temperature, up to an optimum at 27 degrees C. Flowering was also consistently advanced and occurred at lower nodes under LD than under short-day (SD) conditions across the whole range of temperatures. Night interruption for 3 h in the middle of the night was also effective, demonstrating that this is a true photoperiodic response and not merely an effect of increased light integral in LD. It was also confirmed that a distinct vernalisation-type advancement of flowering took place when small, non-dormant plants were exposed to additional chilling at 6 degrees C for several weeks. At low temperatures, a large proportion of the lateral buds were dormant, so that, at 12 degrees C, the plants actually flowered only at their tips. Dissections also revealed that the dormant buds had initiated flowers; but, because of their dormant state, they needed several weeks of chilling before they could flower (biennial-fruiting behaviour). Both types of buds were initiated by the same environmental conditions. Practical applications of the findings are suggested.
Forfattere
Vibeke LindSammendrag
The general aim of this thesis was to gain more knowledge on how the sensory profile and fatty acid composition of meat from lambs were affected when lambs were finished on concentrate and roughage or different types of pastures. The different types of pastures were mountain pastures, cultivated pastures, ryegrass pastures and semi-natural pastures. The effect of gender on meat quality was examined as well. To evaluate the effects of these factors, three studies were performed.In the first study (Paper I) the sensory profile and fatty acid composition in meat from lambs slaughtered directly from unimproved mountain pastures was compared with meat from lambs raised on unimproved mountain pastures and fattened on biodiverse cultivated pastures for 26, 39 and 42 days, respectively, before slaughter. This experiment was conducted at two different locations in Norway in 2006 and 2007, with a total of 124 Norwegian White Sheep (NWS) lambs. Loin samples of M. Longissimus dorsi from lambs above a live body weight of 40 kg were selected and analysed for sensory attributes, and fatty acid composition was determined in the subcutaneous fat over the Longissimus dorsi. Significant differences were found in the sensory attributes of hardness, tenderness, fattiness, metallic and rancid flavour, and in the polyunsaturated fatty acid content between the two treatments.The effects of the different production systems on sensory attributes and fatty acid composition were examined in the second study (Paper II). 150 NWS lambs grazed on the same semi-natural lowland pasture with their dams for three months or more. The effect of pre-slaughter fattening on meat quality was compared using a control group of lambs slaughtered directly from the pasture. Four pre-slaughter treatments were established: weaning and indoor-feeding on concentrate and grass silage for either 44 or 24 days before slaughtering (Conc44, Conc24), and grazing on ryegrass pasture for the same periods (Rye44, Rye24). Loin samples of M. Longissimus dorsi including the subcutaneous fat over the muscle from 15 carcasses from each treatment were analysed for sensory attributes and fatty acid composition. A lower intensity of acid taste was observed in meat from lambs in treatment Conc44 compared with meat from lambs in the control treatment. A higher content of the fatty acids C16:0, C18:1n-9 and C18:2n-6 and the n-6/n-3 ratios was related to meat from lambs fed concentrate, while a higher content of the fatty acids C18:0, C18:1t-11 and C18:3n-3 was found in meat from grazing lambs. In the third study (Paper III), the effect of gender and feeding on the fatty acid composition and sensory profile of meat from NWS lambs was investigated. Lambs from the 2006 treatment in Northern Norway in Study I were used in the first experiment including 22 female and 22 male lambs. In addition, all lambs from Study II, including 46 female and 29 male lambs, were used in the second experiment. Loin samples of M. Longissimus dorsi were analyzed for sensory profile and fatty acid composition. All lambs were slaughtered in September. There were no significant differences in sensory profile between lambs in experiment 1, while in experiment 2, meat from male lambs had higher scores for cloying and rancid flavour and lower scores for sour and sweet taste compared to meat from female lambs. The main conclusions from the present study are that finishing lambs on cultivated pastures can alter the sensory profile and fatty acid composition acquired on mountain pastures to a small degree. Finishing lambs indoors on concentrate and roughage can also alter the fatty acid composition in the meat compared to meat from lambs that graze on semi-natural pastures during the summer. The differences in sensory profile between genders in favour of the meat from female lambs indicate that females may be prioritised over males and off-season fresh meat should preferably be produced from female lambs. Furthermore, male lambs should be given the optimum conditions to be prepared for slaughter early in the season thereby reducing the risk of quality problems. Meat from lambs that is not ready for slaughter when gathered from natural and semi-natural pastures in the autumn should be marketed separately.
Forfattere
Vibeke LindSammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. Aamlid Mats Larsbo Nick JarvisSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. Aamlid Mats Larsbo Nick JarvisSammendrag
Soil water repellency in golf putting greens may induce preferential "finger flow", leading to enhanced leaching of surface applied agrochemicals such as fungicides and nitrate. We examined the effects of root zone composition and the use of the non-ionic surfactant Revolution on soil water repellency, soil water content distributions, infiltration rates, turf quality, and fungicide and nitrate leaching from April 2007 to April 2008. The study was made on 4-year-old experimental green seeded with creeping bentgrass (Agrostis stolonifera L) ‘Penn A-4" at Landvik in southeast Norway. Eight lysimeters with two different root zone materials: (i) straight sand (1% gravel, 96% sand, 3% silt and clay, and 4 g kg-1 organic matter) (SS) and (ii) straight sand mixed with Sphagnum peat to an organic matter content of 25 g kg-1 (SP) were used in this study. Surfactant treatment reduced the spatial variability of water contents, increased infiltration rates and reduced water drop penetration times (WDPTs) by on average 99% in and just below the thatch layer. These effects were most evident for SS lysimeters. Surfactant treatment resulted on average in an 80% reduction of total fungicide leaching, presumably due to reduced preferential finger flow facilitated by decreased soil water repellency. Peat amendment reduced fungicide leaching by 90%, probably due to increased sorption of the fungicides to organic matter. Nitrate leaching was also smaller from surfactant-treated straight-sand root zones, but this effect was not significant.