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.
2016
Forfattere
Sigridur Dalmannsdottir Marcin Rapacz Marit Jørgensen Liv Østrem Arild Larsen Rolf Rødven Odd Arne RognliSammendrag
The expected temperature rise in late summer/early autumn can change the conditions for acclimation and affect the winter survival of perennial crops. This study examined the effect of the temperature just before the onset of cold acclimation (pre-acclimation) on freezing tolerance of timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) populations (both cultivars and breeding populations) adapted to either northern or southern parts of Norway. Using phytotron experiments, we studied whether increasing pre-acclimation temperature delays growth cessation, affects photoacclimation and reduces freezing tolerance. Furthermore, we assessed whether these effects were related to the latitudinal adaptation of the plant material. The results showed that a rise in pre-acclimation temperature decreased both cold acclimation capacity and photoacclimation in these species. This affected the freezing tolerance, which was reduced significantly more in northern-adapted population of timothy and perennial ryegrass compared with southern-adapted populations. Red clover was less affected by temperature changes than the grasses.
Forfattere
Miren del Rio Hans Pretzsch Iciar Alberdi Kamil Bielak Felipe Bravo Andreas Brunner Sonia Condes Mark J Ducey Teresa Fonseca Nikolas Von Lüpke Maciej Pach Sanja Peric Thomas Perot Zahera Souidi Peter Spathelf Hubert Sterba Martina Tijardovic Margarida Tome Patrick Vallet Andres Bravo-OviedoSammendrag
The growth and yield of mixed-species stands has become an important topic of research since there are certain advantages of this type of forest as regards functions and services. However, the concepts and methods used to characterize mixed stands need to be understood, as well as harmonized and standardized. In this review we have compiled a set of measures, indices, and methods at stand level to characterize the structure, dynamics, and productivity of mixed stands, and we discuss the pros and cons of their application in growth and yield studies. Parameters for the characterization of mixed stand structure such as stand density, species composition, horizontal (intermingling) and vertical tree distribution pattern, tree size distribution, and age composition are described, detailing the potential as well as the constraints of these parameters for understanding resource capture, use, and efficiency in mixed stands. Furthermore, a set of stand-level parameters was evaluated to characterize the dynamics of mixed stands, e.g. height growth and space partitioning, self- and alien-thinning, and growth partitioning among trees. The deviations and changes in the behaviour of the analysed parameters in comparison with pure stand conditions due to inter-specific interactions are of particular interest. As regards stand productivity, we reviewed site productivity indices, the growth–density relationship in mixed stands as well as methods to compare productivity in mixed versus monospecific stands. Finally, we discuss the main problems associated with the methodology such as up-scaling from tree to stand level as well as the relevance of standardized measures and methods for improving forest growth and yield research in mixed stands. The main challenges are also outlined, especially the need for qualitatively sound data.
Forfattere
Ilse R. Geijzendorffer Stefano Targetti Manuel K. Schneider Dick J. Brus Philippe Jeanneret Robert H.G. Jongman Martin Knotters Davide Viaggi Siyka Angelova Michaela Arndorfer Debra Bailey Katalin Balázs András Báldi Marion M.B. Bogers Robert G.H. Bunce Jean-Philippe Choisis Peter Dennis Sebastian Eiter Wendy Fjellstad Jürgen K. Friedel Tiziano Gomiero Arjan Griffioen Max Kainz Anikó Kovács-Hostyánszki Gisela Lüscher Gerardo Moreno Juri Nascimbene Maurizio G. Paoletti Philippe Pointereau Jean-Pierre Sarthou Norman Siebrecht Igor Staritsky Siyka Stoyanova Sebastian Wolfrum Felix HerzogSammendrag
1.To evaluate progress on political biodiversity objectives, biodiversity monitoring provides information on whether intended results are being achieved. Despite scientific proof that monitoring and evaluation increase the (cost) efficiency of policy measures, cost estimates for monitoring schemes are seldom available, hampering their inclusion in policy programme budgets. 2.Empirical data collected from 12 case studies across Europe were used in a power analysis to estimate the number of farms that would need to be sampled per major farm type to detect changes in species richness over time for four taxa (vascular plants, earthworms, spiders and bees). A sampling design was developed to allocate spatially, across Europe, the farms that should be sampled. 3.Cost estimates are provided for nine monitoring scenarios with differing robustness for detecting temporal changes in species numbers. These cost estimates are compared with the Common Agricultural Policy (CAP) budget (2014–2020) to determine the budget allocation required for the proposed farmland biodiversity monitoring. 4.Results show that the bee indicator requires the highest number of farms to be sampled and the vascular plant indicator the lowest. The costs for the nine farmland biodiversity monitoring scenarios corresponded to 0·01%–0·74% of the total CAP budget and to 0·04%–2·48% of the CAP budget specifically allocated to environmental targets. 5.Synthesis and applications. The results of the cost scenarios demonstrate that, based on the taxa and methods used in this study, a Europe-wide farmland biodiversity monitoring scheme would require a modest share of the Common Agricultural Policy budget. The monitoring scenarios are flexible and can be adapted or complemented with alternate data collection options (e.g. at national scale or voluntary efforts), data mobilization, data integration or modelling efforts.
Sammendrag
Ten saplings of European ash (Fraxinus excelsior L.) naturally infected by the invasive ash dieback pathogen Hymenoscyphus fraxineus were collected in Ukraine and Norway and examined for bark necrosis and extension of discoloration in sapwood and pith in a stem region. Tissue-specific colonization profiles were determined by spatial analyses of symptomatic and visually healthy stem tissues using a H. fraxineus-specific qPCR assay and light microscopy. Our data suggest that hyphal growth in the starch-rich perimedullary pith is of particular importance for both axial and radial spread of H. fraxineus, but that most of its biomass accumulates in sapwood parenchyma. The study confirms the results from earlier work and presents new information that refines the current stem invasion model.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Sabine Rosner Saskia Luss Jan Svetlik Kjell Andreassen Isabella Børja Lise Dalsgaard R. Evans Ole Einar Tveito Svein SolbergSammendrag
There is evidence that recently occurring top dieback of Norway spruce (Picea abies (L.) Karsten) tress in southern Norway is associated with drought stress. We compared functional wood traits of 20 healthy looking trees and 20 trees with visual signs of top dieback. SilviScan technology was applied to measure cell dimensions (lumen and cell wall thickness) in a selected set of trunk wood specimens where vulnerability to cavitation (P50) data were available. The wall/lumen ratio ((t/b)²) was a quite good proxy for P50. Cell dimensions were measured on wood cores of all 40 trees; theoretical vulnerability of single annual rings could be thus estimated. Declining trees tended to have lower (t/b)² before and during a period of water deficit (difference between precipitation and potential evapotranspiration) that lasted from 2004 to 2006. The results are discussed with respect to genetic predisposition.
Forfattere
Hugh RileySammendrag
Mineral NPK fertilizer and manure have been compared since 1922 in a ley–arable rotation. During 1982–2003, cattle manure at 20–60 Mg ha−1 year−1 yielded 10–20 % less than mineral fertilizer at 100 kg N:25 kg P:120 kg K ha−1 year−1. The higher manure rates gave large nutrient surpluses. Both manure and mineral fertilizer had increased soil organic carbon (SOC), by 11.3 and 3.4 Mg ha−1 in 1996. In order to study possible residual effects, no manure was applied in 2004–2007 and mineral fertilizer was withheld from some NPK plots. Effects on yield and nutrient uptake were evaluated in relation to plots with no nutrient supply since 1922 and plots still receiving 100 kg N, 25 kg P and 120 kg K ha−1 annually. No residual response of mineral fertilizer was found, but previous manure use gave large effects. The latter yields remained around 85 % of those obtained with mineral fertilizer. Previous use of both mineral fertilizer and manure still increased available soil nutrients and pH in 2007. Differences between treatments in SOC had by then declined slightly, to 9.7 and 2.8 Mg ha−1 for manure and mineral fertilizer respectively, relative to the unfertilized control. Manure and fertilizer applications were resumed in 2008, except at the highest previous manure rate, where mean residual responses up to 2014, relative to the unfertilized control, amounted to 55 % higher yield and increases in nutrient uptake of 47 kg N, 8 kg P and 53 kg K ha−1.
Forfattere
Helen Ann Hamilton Eva Brod Ola Stedje Hanserud Erik Olav Gracey Magnus Inderberg Vestrum Anne Bøen Franciska Senta Steinhoff Daniel Beat Müller Helge BrattebøSammendrag
Det er ikke registrert sammendrag
Forfattere
Leif Jarle Asheim Julie Føske Johnsen Øystein Havrevoll Cecilie Marie Mejdell Ann Margaret GrøndahlSammendrag
The study examines the economics of different calf rearing systems and considers effects of suckling and milk feeding on production, health and welfare of dairy cows and growth, milk and feed use, health and welfare of calves. The economics of (i) no suckling, (ii) suckling for 3 days, (iii) suckling for 7 weeks, all assuming milk or milk replacer fed until weaning at 13 weeks, was compared with (iv) suckling for 13 weeks and no milk feeding. A linear programming (LP) model, maximizing profit on a dual purpose dairy-beef farm in lowland eastern Norway, was used for the comparison. Details on calf rearing methods, labor, weaning age, intake of milk, and solid feed were gathered for a sample of organic farms and grouped according to the length of the suckling period. The data were coupled with the National Dairy Herd Recording System (NDHRS) using cross-sectional data for the years 2008–2013. The results of the model study showed that suck- ling up to at least 7 weeks and longer than on most farms in the survey, had a positive influence on the farm economics. This was due to the positive influence on calf growth and health as well as lowered costs. Consequently, dual purpose dairy-beef farmers should be careful to sacrifice calf suckling and restrict calf milk feeding. Long suckling until weaning at 13 weeks was, however, unprofitable.
Forfattere
Ingeborg Callesen Robert Harrison Inge Stupak Jeff Hatten Karsten Raulund-Rasmussen James Boyle Nicholas Clarke Darlene ZabowskiSammendrag
Det er ikke registrert sammendrag