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.
2001
Forfattere
Nina Syversen Brit SalbuSammendrag
The purpose of the study is to use soil particles labeled with the radioactive tracer cesium-134 as a method for studying soil erosion and sedimentation pattern within a small catchment with buffer zones. Cesium is adsorbed to soil particles, and by mea suring changes in the Cs-134 activity on the soil surface, erosion, sedimentation, and pathways for particles can be traced.
Forfattere
Helge SjursenSammendrag
The modification of the weed seed bank in the top soil (0-20 cm) during a six-years period including a sequence of annual crops and a perennial grass-clover ley in the rotation, were analysed in a organic cropping system after conversion to organic farming. The seed bank of dicotyledonous annual species varied from a minimum of 7200 seeds m-2, the year following a three-years period with perennial ley, to a maximum of 17600 seeds m-2, the year following a three-years period with annual crops. The number of species in the seed bank was essentially constant at 18-21 during the rotation, but the number of emerged species in the field decreased from about 19-20 during the annual crop period to a minimum of 8 in 3rd year ley, indicating a reduced input of seeds to the seed bank during the ley period. Dicotyledonous perennial weed seeds in the soil constituted only 2-3% of the seed bank. The correspondence between the soil seed bank and emerged weed plants was not straightforward. For Capsella bursa-pastoris and Chenopodium album, only 41% of the calculated correlations were significantly positive, indicating that an increase in the seed bank only occasionally can predict an increase of the actual weed flora.
Forfattere
Christian Uhlig G Wriedt T Baumgartl T HornSammendrag
This study investigated changes in soil physical and chemical parameters in cultivated and non-cultivated soils due to waterlogging in a laboratory experiment. Mineral soil material from a birch forest and a grass-dominated meadow was taken at Alta, northern Norway. Cultivated soil material showed considerably higher concentrations of organic-C, Kjeldahl-N, and plant available P, K, and Ca. Soil material from the non-cultivated site had a higher proportion of crystallized Fe, while the cultivated soil contained more amorphous and organic-bound Fe. In a laboratory experiment, platinum redox electrodes and porous ceramic cups were placed in the homogenized and waterlogged soil material, and changes in redox potential and Fe concentration were measured over a period of 51 days. Redox potential decreased steadily with increasing time of waterlogging in soils from both sites. In the non-cultivated soil redox potential decreased from +500 to +150 mV, while in cultivated soil it declined from +400 to below 0 mV. The critical redox potential for Fe3+ reduction was between +200 and +150 mV in the cultivated soil, while no mobilization of Fe could be found in the non-cultivated soil. Results indicate that 60 years of cultivation had led to significant changes in physical and chemical responses of the investigated soils due to waterlogging.
Forfattere
John Beck Jensen Jørgen A. Mølmann Jorunn Elisabeth Olsen Lars Sandved Dalen Olavi Junttila Øystein Johnsen Anders Lönneborg Carl Gunnar FossdalSammendrag
To find interesting gene products and to study gene expression in the greenparts of Norway spruce we have sequenced 1101 cDNA clones based on mRNA isolated from needles. Here we present some preliminary findings describing the frequency of different Expressed Sequence Tags (ESTs), the ratio of similarity to known and unknown sequences present in GenBank and sequences not previously reported from Norway spruce. In addition we have tried to place the ESTs into major categories based on putative function
Forfattere
Carl Gunnar Fossdal Lars Sandved Dalen Jørgen A. Mølmann John Beck JensenSammendrag
To find interesting gene products and to study gene expression in the green parts of Norway spruce we have sequenced 1101 cDNA clones based on mRNA isolated from needles. Here we present some preliminary findings describing the frequency of different Expressed Sequence Tags (ESTs), the ratio of similarity to known and unknown sequences present in GenBank and sequences not previously reported from Norway spruce. In addition we have tried to place the ESTs into major categories based on putative function
Forfattere
Christian Uhlig S Monni O JunttilaSammendrag
Empetrum nigrum L. (crowberry) is one of the plants surviving near the Cu-Ni smelters in Finland and Russia. According to field observations, the roots of E. nigrum are situating below 40 cm depth and the root biomass is reduced in the polluted sites. This could cause a reduced root uptake of macronutrients and trace elements in the field, and therefore, the possible element uptake by aboveground parts of E. nigrum was studied in a greenhouse. Six different treatment solutions containing various heavy metal and macronutrient concentrations were applied to the stems and leaves of E. nigrum and the chemical composition and ecophysiological parameters were measured. Heavy metal concentrations in the leaves and stem bark, and Cu concentrations in the stems, increased with increasing metal concentrations in the spraying solutions. The bark and leaves had higher heavy metal concentrations than the stems of comparable age classes. The macronutrient and Mn concentrations in E. nigrum did not change significantly with increasing element concentrations in the spraying solution. Neither the stem water potential nor the leaf chlorophyll concentrations showed any clear response to element applications. Therefore, the element uptake by aboveground parts of E. nigrum was not confirmed by this study. However, there was a tendency to a decrease in CO2 exchange rate and increase in foliar ABA content in plants treated with the highest element concentrations
Sammendrag
Serratia marcescens is one of the most effective bacteria for degradation of chitin, a 1,4-"-linked polymer of N-acetyl-"-D-glucosamine (GlcNAc). Chitinolysis by S. marcescens involves at least four enzymes and a chitin-binding protein. Studies of the enzymology and the structures of the enzymes provide insight in how a natural set of chitinolytic enzymes may be built up. S. marcescens chitinases may find applications as biocontrol agents against fungi and insects.
Forfattere
Peder Gjerdrum M. Warensjö M. NylinderSammendrag
Log sorting according to dimension and quality is the first important step during conversion from sawlog to sawn timber. Crooked logs should be rejected or sawn to reduced yield. The 3D scanner furnish detailed information about the log geometry.Based on cylindrical co-ordinates four new parameters describing the centroid were evaluated: Maximum Radial Deviation (MRD), Standard deviation of the Sweep Angle (SSA), Distance from Log End to MRD (DLE), and Residual between the Radial deviation and a skew sinusoidal Model (RRM). 56 unbarked spruce logs were sampled, representing six different crook types denoted I, J, C, V, Z and S according to their curvature.Algorithms were established by means of logistic regression models to distinguish between several crook classes. It was concluded that the 3D scanner can be programmed to effectively perform automatic crook detection and classification.
Forfattere
Oddvar SkreSammendrag
Direct and indirect effects of increased CO2 level on the mountain birch ecosystem are reviewed and evaluated, and supplemented with some case studies on mountain birch (Betula pubescens) based on field experiments at different altitudes and greenhouse experiments at elevated CO2 and winter temperature level. These studies have shown that large differences exist in responses on climate change between mountain birch populations, and that these differences may be related to the climate at their habitat.
Forfattere
Maria Sørensen Arild Ernstsen Leidulf Lund Jarle Nilsen Anders Lönneborg Øystein JohnsenSammendrag
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