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
Sammendrag
Yields are reported from four long-term (16 30 years) tillage trials, comparing results since 1998, under relatively wet conditions, with earlier experience. In trial 1, on clay loam, mean grain yield with spring harrowing only, has since 1998 been 87% of that obtained with autumn ploughing, whereas it was 94% for the whole period since 1991. The inclusion of autumn harrowing increased these figures to 94 and 98%, respectively. Over the last six years, spring ploughing gave 5% lower yield than did autumn ploughing. Relative yields of unploughed versus ploughed treatments were negatively correlated with summer rainfall. Grain protein was lowest with spring harrowing only. In trial 2, on clay loam, direct drilling has since 1998, as in previous years, given around 10% lower yield than has autumn ploughing. Autumn harrowing gave 4% lower yield in winter wheat and 6% higher yield in spring oats than did autumn ploughing, whilst yields of spring turnip rape were not significantly affected by tillage. In trial 3, also on clay loam, six alternative straw treatments were compared under four unploughed tillage regimes. Relative to straw removal, retaining large residue amounts depressed yields hardly at all with autumn and spring harrowing, but by 7% with spring harrowing only and by 13% with direct drilling. Overall, direct drilling gave 18% lower yields in this trial than did autumn and spring harrowing, whilst the yield reduction with spring harrowing only was 7%. In trial 4, on silt loam, both spring harrowing only and direct drilling have since 1998 given 6% lower yield than has autumn ploughing, whereas autumn and spring harrowing has given 6% higher yield. Under drier conditions during 1991 1997, autumn ploughing gave up to 11% lower yield than did unploughed treatments. Straw retention was beneficial in the absence of ploughing during that period, but has had little effect in more recent years.
Forfattere
Svein Halvor Knutsen S. Dimitrijevic E. L. Molteberg Vegard Segtnan Lene Kaaber Trude WicklundSammendrag
Freeze-dried potato samples were obtained from the varieties Saturna and Peik that had been subjected to different agronomic conditions and storage. Powdered samples originating from the same growth year were mixed with oil and heated simultaneously in a stone oven in order to study the potential for acrylamide (AA) formation in a fixed time and temperature situation. For baked samples originating from unstored potato a linear relationship was found between asparagine (Asn) and reducing sugar (RS) content and AA formation. For these samples the AA content varied linearly with a* except from samples that originally were high or low in Asn. Upon storage the correlation between the quantity of the common precursors, Asn and RS, and AA were smaller. Results of the baking experiments suggest that the AA potential for stored potato cannot be predicted from RSs and Asn alone, and that other factors that might change during storage are of importance. Due to north European conditions the RSs might not always be the limiting substrate for AA formation. Additional information for the precursor content in 2004 and 2005 are included. No systematic effect on precursor contents related to chemical vine killing was observed. Precursor contents varied among and between varieties, different cultivation years and growth sites. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
Forfattere
Per Otto Flæte Olav HøibøSammendrag
Variation in heartwood diameter (HWD) along the stem was studied in 106 mature Scots pines (Pinus sylvestris L.) sampled from southern Norway. HWD decreased from the base towards the treetop, following a profile similar to that of the stem diameter (shape of the tree). A few trees deviated from this general pattern. In these trees HWD increased from the base of the stem to a maximum at 2-2.5 m and then decreased towards the top of the tree. Random coefficient mixed models based on a second-degree polynomial of vertical position in the tree and tree variables that can be measured in the forest were developed to predict HWD profiles of pine stems. Seven different models were developed in steps, based on how easily the input variables can be measured. Input variables consisted of information describing the size and shape of trees and information from increment cores. Performances of the models were validated with an independent sample (R-2 = 0.88-0.95, root mean square error = 12-19 mm). The high predictive abilities of the models indicate that they can be prospective tools for selecting trees and stem sections within trees to produce logs with HWD suitable for manufacturing of heartwood sawn-wood products.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
This paper reports a study on soil development in loamy marine sediments on both sides of the Oslofjord (Vestfold, Ostfold). This region has been subject to steady glacio-isostatic uplift during the whole Holocene. Hence, land surface age continuously increases from the coast inland. Several sea level curves, based on radiocarbon datings, enable estimation of land surface age for all locations. Clay illuviation starts in less than 1650 years. E horizons become lighter with age, but their lower boundary stays around 40 cm for more than 10 000 years. Albeluvic tongues develop between 4600 and 6200 years. Initially, they form along intersections of cracks. As preferential flow and leaching along the cracks continues, the tongues increase in length and width, progressively consuming the prisms between the cracks in the upper Bt horizon. The Fe-d/Fe-t ratios (weighted means of the upper meter) show a clear linear increase with soil age and may be used for "pedo-dating", i.e. for estimating the ages of non-dated land surfaces covered with similar sediments. In contrast, the logarithmic decrease of base saturation and pH, with rapid changes in the first time but only very slight changes between 2000 and 10 000 years, makes these parameters unsuitable for "pedo-dating". (c) 2008 Elsevier Ltd and INQUA. All rights reserved.
Forfattere
Sjur Baardsen Gudbrand Lien Ståle StørdalSammendrag
The objective of tills article wits to explore how marginalization of revenues front timber sales relative to income from agriculture and employment affects profit efficiency (the ratio of actual profit to maximum obtainable profit). We also sought to identify and measure the effects of other relevant inefficiency factors. A translog profit. frontier function with all inefficiency module was estimated using a panel of 2.265 observations of 385 active Norwegian forest. owners for 1991-2004. We found that profit efficiency decreases as the revenues from timber sales fall relative to agricultural or wage income. Other factors decreasing the efficiency were logging distance (beyond what can be explained by logging costs), fragmentation of the forest property, and time. Factors increasing profit efficiency were experience (age). information (possession of a management. plan). and geographical location (centrality). Oil the basis of our results we make recommendations oil how forest owners can improve their profit. efficiency. We also suggest further developing and streamlining contract regimens as policy instruments for promoting efficiency. FOR. SCI. 55(6).524-532.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Johanne E. Schjøth Angelo Visconti Leif SundheimSammendrag
Field experiments in the high rainfall zone (HRZ) and the medium rainfall zone (MRZ) in Zambia were designed to determine the natural occurrence of fumonisins (FB1-2) in Zambian maize hybrids, accumulation of FB1-2 resulting from artificial inoculation with Fusarium verticillioides and effects of climate and planting time on FB1-2 in maize. Combined FB1-2 concentrations varied from 0 to 13,050 ng/g, with an overall mean of 666 ng/g. Maize from the HRZ had low incidences of FB1-2-positive samples (mean 41%) which contained FB1-2 below 500 ng/g. In the MRZ, higher incidences (mean 97%) and concentrations (40% of samples > 1,000 ng/g) were recorded in two out of three years. There was no correlation between mean location FB1-2 concentrations in individual years and precipitation, number of rain days or monthly precipitation. Postponing the planting time with 10 or 20 days did not significantly affect FB1-2 concentration, but it reduced the yields in some years.
Forfattere
Hege Nordheim-Viken Harald VoldenSammendrag
It is concluded that the ruminal aNDF degradation characteristics are affected by maturity Stage, and interactions with climatic factors such as temperature and water availability probably interact with maturity stage. Precautions should he made when prediction feed degradation characteristics from multiple regression analyses. (C) 2008 Published by Elsevier B.V.
Forfattere
Geir Mathiesen Anita Sveen May Bente Brurberg Lasse Fredriksen Lars Axelsson Vincent EijsinkSammendrag
Conclusion: This is the first comprehensive experimental study showing that predicted SPs in the L. plantarum genome actually are capable of driving protein secretion. The results reveal considerable variation between the SPs that is at least in part dependent on the protein that is secreted. Several SPs stand out as promising candidates for efficient secretion of heterologous proteins in L. plantarum. The results for NucA provide some hints as to the sequence-based prediction of SP functionality, but the general conclusion is that such prediction is difficult. The vector library generated in this study is based on exchangeable cassettes and provides a powerful tool for rapid experimental screening of SPs.