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.
2018
Authors
Arne BardalenAbstract
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Authors
Panu Korhonen Taru Palosuo Tomas Persson Mats Höglind Guillaume Jégo Marcel Van Oijen Anne-Maj Gustavsson Gilles Bélanger Perttu VirkajärviAbstract
During the past few years, several studies have compared the performance of crop simulation models to assess the uncertainties in model-based climate change impact assessments and other modelling studies. Many of these studies have concentrated on cereal crops, while fewer model comparisons have been conducted for grasses. We compared the predictions for timothy grass (Phleum pratense L.) yields for first and second cuts along with the dynamics of above-ground biomass for the grass simulation models BASGRA and CATIMO, and the soil-crop model STICS. The models were calibrated and evaluated using field data from seven sites across Northern Europe and Canada with different climates, soil conditions and management practices. Altogether the models were compared using data on timothy grass from 33 combinations of sites, cultivars and management regimes. Model performances with two calibration approaches, cultivar-specific and generic calibrations, were compared. All the models studied estimated the dynamics of above-ground biomass and the leaf area index satisfactorily, but tended to underestimate the first cut yield. Cultivar-specific calibration resulted in more accurate first cut yield predictions than the generic calibration achieving root mean square errors approximately one third lower for the cultivar-specific calibration. For the second cut, the difference between the calibration methods was small. The results indicate that detailed soil process descriptions improved the overall model performance and the model responses to management, such as nitrogen applications. The results also suggest that taking the genetic variability into account between cultivars of timothy grass also improves the yield estimates. Calibrations using both spring and summer growth data simultaneously revealed that processes determining the growth in these two periods require further attention in model development.
Authors
Ahmad Hamidov Katharina Helming Gianni Bellocchi Waldemar Bojar Tommy Dalgaard Bhim Bahadur Ghaley Christian Hoffmann Ian Holman Annelie Holzkämper Dominika Krzeminska Sigrun Hjalmarsdottir Kværnø Heikki Lehtonen Georg Niedrist Lillian Øygarden Pytrik Reidsma Pier Paolo Roggero Teodor Rusu Cristina Santos Giovanna Seddaiu Eva Skarbøvik Domenico Ventrella Jacek Żarski Martin SchönhartAbstract
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Report research – Phosphorus losses from the Mørdre catchment
Dominika Krzeminska, Marianne Bechmann
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Authors
Holger LangeAbstract
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Authors
O. Janne Kjønaas Sunil Mundra Teresa Gómez de la Bárcena Mette Hansen Gro Hylen Håvard KauserudAbstract
Tree species change has been suggested as one of the government policies to mitigate climate change in Nor-way with the aim to increase the annual uptake of CO2 and the long-term storage of carbon (C) in forests. The strategy includes replacing native, deciduous species with fast-growing species, mainly Norway spruce. A shift in tree species is expected to affect the pools and fluxes of C in the stand as well as the microbial community. As part of the BalanC project, we assess C storage related to shift in tree species cover in western Norway and whether a corresponding shift in soil microbial communities are happening. The study aim at integrating results on soil respiration, C mineralization, soil stability, diversity of bacteria, fungi and micro-eukaryotes, soil nutrient pools, litter inputs and edaphic factors at the stand level in order to identify key drivers for changes in the soil C stocks. Fifteen paired plots of native birch and planted Norway spruce at five locations were sampled. Prelimi-nary results suggests a redistribution of C from the mineral soil to the forest floor in the spruce stands, with minor changes in the total soil C pools over the 45-60 years since the tree species change. The in situ soil respi-ration and heterothropic respiration, as well as C mineralization rates, were higher in birch than in spruce stands. Differences in C mineralization rates attenuate with depth between forest types. The microbial com-munities of the three organismal groups were all strongly structured along the vertical depth.
Abstract
The boreal forest is a key ecosystem for global C sequestration and storage. Microorganisms in soil have crucial functions in regulating these processes. Fungi are typically sharply structured with soil depth, but we largely lack such information for other microorganism, including bacteria and other micro-eukaryotes. To improve our knowledge of how different microorganisms are structured vertically and how they might interact, we investi-gated the communities of bacteria, fungi and micro-eukaryotes in four different soil horizons in natural birch forests in Western Norway. The communities of all three organismal groups were strongly structured along the vertical depth. Our results support the hypothesis that natural decrease in nutrient availability and pH differ-ences between organic and mineral horizons affect the distribution of soil microorganisms. Proteobacteria, Actinobacteria and Planctomycetes dominated in the uppermost organic layer while Acidobacteria and Firmicu-tes in mineral layers. Proportionally, fungi dominated in mineral layers whereas other micro-eukaryotes (Meta-zoa, Apicomplexa, Conosa, Ochrophyta and Chlorophyta) in organic layers. Ascomycota were relatively more abundant in mineral layers compared to Basidiomycota and Cryptomycota. Nematoda, Annelida and Arthropo-da showed decreasing trends with depth. Furthermore, different optima in the depth distribution of ectomy-corrhizal and saprotrophic genera was observed, supporting the view that different genera are adapted to different niches along the soil depth gradient. Network analyses will be used to infer tentative biotic interac-tions between the microbial groups and how this varies with soil depth.