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.
2014
Sammendrag
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Sammendrag
Variable retention harvesting is acknowledged as a cost-effective conservation measure, but previous studies have focused on the environmental value and planning cost. In this study, a model is presented for optimizing harvesting cost using a high resolution map generated from airborne laser scanning data. The harvesting cost optimization model is used to calculate the objective value of different scenarios. By comparing the objective values, better estimates of the opportunity cost of woodland key habitats are found. The model can be used by a forest manager when evaluating what silvicultural treatments to implement or as an input for improving the nature reserve selection problem for woodland key habitats or retention patches. The model was tested on four real-world cases, and the results indicate that terrain transportation costs vary more than reported in the literature and that it may be worthwhile to divide the opportunity cost into its direct and indirect components.
Forfattere
Nils Egil SøvdeSammendrag
Ground based systems are the main approach used for off-road timber transportation throughout the world. Estimates of terrain transportation costs are required for several forest planning problems and for assessment of harvesting contracts and forest land values. Methods for these calculations can be categorized into two groups. Methods based on average transportation distance predate computers, are analytical, and based on manual calculations. Network methods are based on a digital raster representation and are solved with numerical computations. Here, the two categories are compared and linked. Analytical methods in the literature have been limited to flat terrain and including detail is difficult. The network method can be extended to include uneven terrain or detailed input data.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Since the late nineteenth century when high-cost equipment was introduced into forestry there has been a need to calculate the cost of this equipment in more detail with respect to, for example, cost of ownership, cost per hour of production, and cost per production unit. Machine cost calculations have been made using various standard economic methods, where costs have been subdivided into capital costs and operational costs. Because of differences between methods and between national egulations, mainly regarding tax rules and subsidies, inter-national comparisons of machine costs are difficult. To address this, one of the goals of the European Cooperation in Science and Technology (COST) Action FP0902 was to establish a simple format for transparent cost calculations for machines in the forest biomass procurement chain. A working group constructed a Microsoft Excel – based spreadsheet model which is easy to understand and use. Input parameters are easy to obtain or possible to estimate by provided rules of thumb. The model gives users a simultaneous view of the input parameters and the resulting cost outputs. This technical note presents the model, explains how the calculations are made, and provides future users with a guide on how to use the model. Prospective users can view the model in the Supplementary Material linked to this article online
Forfattere
Kari Marie Njåstad Steffen Adler Jens Hansen-Møller Erling Thuen Anne-Maj Gustavsson Håvard SteinshamnSammendrag
Dietary phytoestrogens are metabolized or converted in the gastrointestinal tract of ruminants, only limited knowledge exists on the extent and location of this conversion in vivo. The objective of this study was to quantify the gastro-intestinal metabolism of phytoestrogens in lactating dairy cows fed silages with different botanical composition. Four lactating rumen cannulated Norwegian Red cattle were assigned to a 4 × 4 Latin square with 1 cow per treatment period of 3 wk. The 4 treatment silages were prepared from grasslands with different botanical compositions: organically managed short-term timothy (Phleum pratense L.) and red clover (Trifolium pratense L.) ley (2 yr old: ORG-SG); organically managed long-term grassland with a high proportion of unsown species (6 yr old; ORG-LG); conventionally managed perennial ryegrass (Lolium perenne L.) ley (CON-PR); and conventionally managed timothy ley (CON-TI). The herbages were cut, wilted, and preserved with additive in round bales, fed as a mix of the first and third cut at 90% of ad libitum intake, and contributed to 70% of the total dry matter intake. Milk, feed, omasal digesta, urine, and feces were collected at the end of each period and analyzed for the concentrations of phytoestrogens by using a liquid chromatography–tandem mass spectrometry technique. Concentration of total isoflavones was highest in ORG-SG and lowest in CON-TI silage, whereas the content of total lignans was highest in the grass silages. The isoflavones were extensively metabolized in the rumen on all diets, and the recovery of formononetin and daidzein in omasum, mainly as equol, averaged 0.11 mg/mg. The apparent intestinal metabolism was less severe as, on average, 0.29 mg/mg of the omasal flow was recovered in feces. The plant lignans were also strongly degraded in the rumen. However, the flow of lignans to omasum and excretion in feces were, on average, 7.2- and 5.2-fold higher, respectively, than the intake of the plant lignans matairesinol and secoisolariciresinol, known as precursors of mammalian lignans. Thus, excretion to milk could not be directly related to intake, implying that plant lignans other than matairesinol and secoisolariciresinol in forage are precursors for enterolactone production in the rumen and for its content in milk. Equol followed mainly the flow of large particles out of the rumen, whereas the mammalian lignans were distributed between phases proportional to dry matter flow. The main metabolism of phytoestrogens occurred in the rumen and the main route of excretion was through feces and urine, with only a small part being excreted in milk. The concentration of phytoestrogens in milk can be manipulated through intake but the intermediate transfer capacity to milk appears to be limited by saturation
Forfattere
Hans Estrup Andersen Gitte Blicher-Mathiesen Marianne Bechmann Arvydas Povilaitis Arvo Iital Ainis Lagzdins Katarina KyllmarSammendrag
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Forfattere
Johannes Deelstra Arvo Iital Arvydas Povilaitis Katarina Kyllmar Inga Greipsland Gitte Blicher-Mathiesen Viesturs Jansons Jari Koskiaho Ainis LagzdinsSammendrag
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Sammendrag
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Forfattere
Jens Kværner Ole Martin Eklo Eivind Solbakken Ivar Solberg Stein SorknesSammendrag
The study examines the influence of agricultural activities on pesticides in groundwater in an area with fluvial deposits of sand with a top layer of sandy silt and silt, intensive cultivation of potatoes and cereals, and drinking water supplies of households from local groundwater wells. Information about local agricultural practice and washing sites for pesticide spraying equipment, properties of soils and deeper deposits, hydrogeology and groundwater flow, simulations of pesticide leaching, and contents of pesticides and nitrate in groundwater samples from drinking water wells was used to explore extension and reasons of pesticide contamination of groundwater. Pesticides were found in a majority of the sampled wells. Eight different pesticides and metabolites were detected in groundwater samples. The results demonstrate that on fluvial deposits diffuse pollution from spraying of fields with pesticides can result in groundwater contamination in Nordic climate. Higher concentrations of pesticides in some wells can be explained by point source contamination from washing sites. The occurrence of pesticides in drinking water wells touches up the question whether pesticides should be given general approvals, or approvals should include restrictions or recommendations regarding use on areas with high risk of groundwater contamination. Combination of washing sites for pesticide spraying equipment and groundwater wells for drinking water requires attention, proper equipment and practice, and knowledge about pesticides, soil and water to avoid contamination. Samples from wells adjacent to washing sites for pesticide equipment might overestimate average pesticide concentrations in groundwater bodies. In Nordic areas attention should be given to pesticide pollution of shallow groundwater in fluvial deposits. To provide basis for interpretation of results and planning of mitigation measures against pesticide contamination, an integrated approach using information about agronomical practice and point sources, soil properties, hydrogeology and simulations of pesticide leaching is recommended for future surveys and monitoring of pesticides in groundwater.