Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2010
Abstract
Norwegian agriculture is mainly dominated by grass-based milk and livestock production, so winter damage to overwintering grasses may have large economic consequences. We assessed the impact of climate change on the winter survival of timothy (Phleum pratense L) and perennial ryegrass (Lolium perenne L) under Norwegian conditions using agroclimatic indices and a simulation model of frost tolerance. This study was based on locally adjusted future climate scenarios (two for the period 2071-2100; one for the period 2020-2049) for six important agricultural regions, represented by one location each. We proposed and validated a rough way to estimate the daily minimum air temperatures from scenario data. compared with the control period 1961-1990, the future hardening period will be shortened by up to 21 days. As a consequence, the modelled maximum frost tolerance is expected to be reduced by up to 3.9 degrees C and 1.9 degrees C for timothy and perennial ryegrass, respectively, under the warmest scenario. In spite of this reduction, the plants are expected to be hardy enough to withstand the predicted autumn frosts, and we also expect a general reduction in the risk of winter frost injuries. The plant data available to this study suggest that agroclimatic indices developed for Canadian conditions can be useful for assessing the hardening status in timothy and perennial ryegrass. However, such indices are less suitable for assessing the risk of plant injury related to frost and ice encasement in Norway, since they do not account for the dynamics of cold adaptation. Although less snow is expected, in most cases this will not be accompanied by an increase in the risk of ice encasement injuries. However, a slight increase in the number of ice encasement events was predicted for one location. An earlier start of growth was predicted for all locations, accompanied at one coastal location by a slightly increased predicted risk of spring frosts. There is little risk of winter injuries related to frost and ice encasement in the hardier grass species timothy. The better overwintering conditions in general indicate that it will be possible to grow perennial ryegrass in areas where it is not grown today, provided the risk of fungal diseases does not increase. (C) 2010 Elsevier B.V. All rights reserved.
Abstract
Timothy (Phleum pratense L) is the most important forage grass in Scandinavia and it is therefore highly interesting to study how it will perform in a changing climate. In order to model winter survival, the dynamics of hardening and dehardening must be simulated with satisfactory precision. We investigated an early timothy frost tolerance model (LT50 model), and an LT50 model for winter wheat. Based on the assumption that timothy has no vernalization requirement, unlike winter wheat, but does have the ability to adapt to cold temperatures in a process linked to stage of development, two alternative versions of the winter wheat model were also constructed. In total, these four candidate models were calibrated by a Bayesian approach for the timothy cultivar Engmo. The candidate models were validated using independent observations on LT50 in timothy at different locations reflecting differences in climate. A sensitivity analysis, using the Morris method, to identify important model parameters suggested that there is a connection between frost tolerance and stage of plant development, even if there is no vernalization requirement. The simplified winter wheat model was selected as the best candidate model for LT50 in timothy based on model selection criteria and its ability to capture the hardening and dehardening processes. The results from the Bayesian calibration suggest that there are no major regional differences in Norway calling for regional calibration. However, cultivar-specific calibration is probably required, since there are hardy and less hardy cultivars within the same species. A functional LT50 model would allow risk assessments to be made of future winter survival using specifically tailored and downscaled climate scenarios. (C) 2010 Elsevier B.V. All rights reserved.
Abstract
Side effects related to liming have been studied in four dimictic lakes (553-642 ma.s.l.; 59 degrees 57'N) in Finnemarka, a forested area in Southern Norway with poor catchment buffer capacity. Data series from lake profiles have been sampled two decades apart; 10 years prior to liming and after 10 years of liming. Water samples were collected during spring after ice breakup and during summer after the development of thermal stratification. Before liming, there were very low concentrations of bicarbonate (HCO3-; or alkalinity) in the lakes. After 10 years of liming, up to 90% of the ions in hypolimnion originate from lime products. Hence, liming strengthened the chemical stratification and increased the vertical stability. Differences in chemocline developments between lakes were explained by differences in physical properties, i.e. their depth/surface area ratio. The chemocline developments lead to increased concentrations of organic matter in the hypolimnion with a subsequent reduction in oxygen concentrations. Lime additions during late spring, as an alternative to early autumn, lead to pronounced anoxic conditions in the hypolimnion.
Authors
Bringas Carlos M. Salas Tore Filbakk Geir Skjevrak Odd-Ivar Lekang Olav Høibø Reidar Barfod SchüllerAbstract
The effects of drying temperature and storage time on the compressibility and strength of Scots pine pellets were analysed in this article. Compressibility was not affected, whereas the highest pellet strength was obtained from the wood with longest storing and highest drying temperature.
Authors
Christian Sonne Jan Ove Bustnes Dorte Herzke Veerle Jaspers Adrian Covaci Duncan Halley Truls Moum Igor Eulaers Marcel Eens Rolf A. Ims Sveinn Are Hanssen Kjell E Erikstad Trond Johnsen Lisbeth Schnug Frank F. Rigét Asger Lundorff JensenAbstract
Organohalogen contaminants (OHCs) may affect various physiological parameters in birds including blood chemistry. We therefore examined blood plasma clinical-chemical parameters and OHCs in golden eagle, white-tailed eagle and goshawk chicks from Northern Norway. Correlation analyses on pooled data showed that alkaline phosphatase (ALKP), glucose and creatinine were significantly negatively correlated to various OHCs (all: p<0.05; r: -0.43 to -0.55; n=23), while alanine aminotransferase (ALAT), total protein, cholesterol, uric acid, total bilirubin, ratios protein:creatinine and uric acid:creatinine were significantly positively correlated to various OHCs (all: p<0.05; r: 0.43-0.96). Based on these relationships, we suggest that the OHC concentrations found in certain raptor chicks of Northern Scandinavia may impact blood plasma biochemistry in a way that indicates impacts on liver, kidney, bone, endocrinology and metabolism. In order to elaborate further on these relationships and mechanisms, we recommend that a larger study should take place in the near future.
Authors
Gudbrand Lien Subal C. Kumbhakar J. Brian HardakerAbstract
No abstract has been registered
Abstract
Scenarios of climate changes indicate longer and more frequent spells of mild weather during winter in northern latitudes. De-hardening in perennial grasses could increase the risk of frost kill. In this study, the resistance to de-hardening of different grass species and cultivars was examined, and whether the resistance changes during winter or between years, was tested. In Experiment 1, two cultivars of timothy (Phleum pratense L.) and perennial ryegrass (Lolium perenne L.) of contrasting winter hardiness were grown under ambient winter conditions, transferred from the field in January and April 2006 to the laboratory for 9 d with controlled de-hardening conditions of 3°C, 9°C and 15°C. The timothy cultivars were tested at 3°C, 6°C and 9°C in a similar experiment (Experiment 2) in January 2007. De-hardening, measured as decrease in frost tolerance (LT50), was less in timothy than in perennial ryegrass and increased with increasing temperatures. The northern winter-hardy cultivar Engmo of timothy de-hardened more rapidly than the less-hardy cultivar Grindstad, but had higher initial frost tolerance in both experiments, whereas there was less difference between cultivars of perennial ryegrass in Experiment 1. Cultivar Grindstad of timothy lost all hardiness in early spring at all temperatures, whereas cultivar Engmo maintained some hardiness at 3°C. Cultivar Engmo de-hardened at a lower rate in 2007 than in 2006, in spite of similar frost tolerance at the start of de-hardening treatment in both years. This indicates that the rate of de-hardening was controlled by factors additional to the initial frost tolerance and that autumn weather conditions might be important for the resistance to de-hardening.
Authors
Sebastian EiterAbstract
This article uses an activity-based understanding of landscape to explore values related to perceived land cover diversity. Perceptions within two user groups, members of landowner families and hiking tourists in a mountain area in western Norway, were related to a simultaneous land cover survey, and compared to experts' evaluations of land cover and to the aims of landscape protection in the area. Users perceived the area as being significantly more diverse and valuable than experts did, which stresses the importance of taking user perception into account in landscape protection and management. Some central landscape values were dependent upon land use outside the boundaries of the protected area. This illustrates that measures within structurally defined land units are not necessarily sufficient for maintenance of landscape values experienced by users. Land use in both respects, as an upholder of values and as a way of experiencing or perceiving them, should receive an increased role in the determination of management units.
Abstract
No abstract has been registered
Authors
Jon Anders Stavang Rolf Inge Pettersen Micael Wendell Knut Asbjørn Solhaug Olavi Junttila Roar Moe Jorunn E. OlsenAbstract
Active gibberellin (GA(1)) is an important mediator of thermoperiodic growth in pea. Plants grown under lower day than night temperature (negative DIF) elongate less and have reduced levels of GA(1) compared with plants grown at higher day than night temperature (positive DIF). By comparing the wild type (WT) and the elongated DELLA mutant la cry(s), this study has examined the effect of impaired GA signalling on thermoperiodic growth, photosynthesis, and respiration in pea. In the WT a negative DIF treatment reduced stem mass ratio and increased both root mass ratio and leaf mass ratio (dry weight of specific tissue related to total plant dry weight). Leaf, root and stem mass ratios of la cry(s) were not affected by DIF. Under negative DIF, specific leaf area (projected leaf area per unit leaf dry mass), biomass, and chlorophyll content of WT and la cry(s) plants were reduced. Young, expanding leaves of plants grown under negative DIF had reduced leaf area-based photosynthetic capacity. However, the highest photosynthetic electron transport rate was found in fully expanded leaves of WT plants grown under negative DIF. Negative DIF increased night respiration and was similar for both genotypes. It is concluded that GA signalling is not a major determinant of leaf area-based photosynthesis or respiration and that reduced dry weight of plants grown under negative DIF is caused by a GA-mediated reduction of photosynthetic stem and leaf tissue, reduced photosynthesis of young, expanding leaves, and reduced growth caused by low temperature in the photoperiod.