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
Leif Sundheim Christer Magnusson Arild Sletten Per Hans Micael Wendell Guro Brodal Åshild Ergon Halvor Solheim Anne Marte Tronsmo Trond RafossAbstract
No abstract has been registered
Authors
Rachel Cassidy Philip Jordan Marianne Bechmann Brian Kronvang Katarina Kyllmar Mairead ShoreAbstract
Achieving an operational compromise between spatial coverage and temporal resolution in national scale river water quality monitoring is a major challenge for regulatory authorities, particularly where chemical concentrations are hydrologically dependent. The efficacy of flow-weighted composite sampling (FWCS) approaches for total phosphorus (TP) sampling (n = 26–52 analysed samples per year), previously applied in monitoring programmes in Norway, Sweden and Denmark, and which account for low to high flow discharges, was assessed by repeated simulated sampling on high resolution TP data. These data were collected in three research catchments in Ireland over the period 2010–13 covering a base-flow index range of 0.38 to 0.69. Comparisons of load estimates were also made with discrete (set time interval) daily and sub-daily sampling approaches (n = 365 to >1200 analysed samples per year). For all years and all sites a proxy of the Norwegian sampling approach, which is based on re-forecasting discharge for each 2-week deployment, proved most stable (median TP load estimates of 87–98%). Danish and Swedish approaches, using long-term flow records to set a flow constant, were only slightly less effective (median load estimates of 64–102% and 80–96%, respectively). Though TP load estimates over repeated iterations were more accurate using the discrete approaches, particularly the 24/7 approach (one sample every 7 h in a 24 bottle sampler - median % load estimates of 93–100%), composite load estimates were more stable, due to the integration of multiple small samples (n = 100–588) over a deployment.
Authors
Donghai Wu Philippe Ciais Nicolas Viovy Alan K. Knapp Kevin Wilcox Michael Bahn Melinda D. Smith Sara Vicca Simone Fatichi Jakob Zscheischler Yue He Xiangyi Li Akihito Ito Almuth Arneth Anna Harper Anna Ukkola Athanasios Paschalis Benjamin Poulter Changhui Peng Daniel Ricciuto David Reinthaler Guangsheng Chen Hanqin Tian Helene Genet Jiafu Mao Johannes Ingrisch Julia E.S.M. Nabel Julia Pongratz Lena R. Boysen Markus Kautz Michael Schmitt Patrick Meir Qiuan Zhu Roland Hasibeder Sebastian Sippel Shree R.S. Dangal Stephen Sitch Xiaoying Shi Yingping Wang Yiqi Luo Yongwen Liu Shilong PiaoAbstract
Field measurements of aboveground net primary productivity (ANPP) in temperate grasslands suggest that both positive and negative asymmetric responses to changes in precipitation (P) may occur. Under normal range of precipitation variability, wet years typically result in ANPP gains being larger than ANPP declines in dry years (positive asymmetry), whereas increases in ANPP are lower in magnitude in extreme wet years compared to reductions during extreme drought (negative asymmetry). Whether the current generation of ecosystem models with a coupled carbon– water system in grasslands are capable of simulating these asymmetric ANPP responses is an unresolved question. In this study, we evaluated the simulated responses of temperate grassland primary productivity to scenarios of altered precipitation with 14 ecosystem models at three sites: Shortgrass steppe (SGS), Konza Prairie (KNZ) and Stubai Valley meadow (STU), spanning a rainfall gradient from dry to moist. We found that (1) the spatial slopes derived from modeled primary productivity and precipitation across sites were steeper than the temporal slopes obtained from interannual variations, which was consistent with empirical data; (2) the asymmetry of the responses of modeled primary productivity under normal inter-annual precipitation variability differed among models, and the mean of the model ensemble suggested a negative asymmetry across the three sites, which was contrary to empirical evidence based on filed observations; (3) the mean sensitivity of modeled productivity to rainfall suggested greater negative response with reduced precipitation than positive response to an increased precipitation under extreme conditions at the three sites; and (4) gross primary productivity (GPP), net primary productivity (NPP), aboveground NPP (ANPP) and belowground NPP (BNPP) all showed concave-down nonlinear responses to altered precipitation in all the models, but with different curvatures and mean values. Our results indicated that most models overestimate the negative drought effects and/or underestimate the positive effects of increased precipitation on primary productivity under normal climate conditions, highlighting the need for improving eco-hydrological processes in those models in the future.
Authors
Francisco Javier Ancin Murguzur Aitor Barbero-Lopez Sari Kontunen-Soppela Antti HaapalaAbstract
Microbial growth on culture media is a commonplace technique to estimate the growth rate and virulence ofmicrobes, assess inhibitory effects of compounds and estimate potential damages of plant pathogens in agri-culture. Growth area measurement of solid cultures is still commonly performed as a manual process that re-quires skilled technicians and substantial time, thus warranting an automated system to reduce the workload andincrease measurement efficiency. A machine learning approach (Support Vector Machines) was developed tofully automate the area measurement process. We developed a functional model that processes images andreturns the microbial area coverage considerably faster than a manual measurement method, with minimal userinput and highly comparable results (R2= 0.88, kappa = 0.88) applicable over large datasets.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Astrid Johansen Anne Kjersti Bakken Anne Langerud Ragnhild Borchsenius Sverre Heggset Atle HaugnesAbstract
No abstract has been registered
Authors
Astrid Johansen Anne Kjersti Bakken Anne Langerud Ragnhild Borchsenius Sverre Heggset Atle HaugnesAbstract
In a farm sceale study three baling strategies were examined in order to document harvesting losses as well as quality of the resulting silage. It was concluded that it is possible to avoid comprehensive harvesting losses and to achieve satisfactory fermented, late harvested Whole crop wheat silage bu use of traditional balers. Application of acid based additve had no significant impact on starch degradation in this Experiment, and the effect on fermentation pattern was inconsistent.
Authors
C. Rikard Unelius S Ganji Christian Schiebe Tao Zhao Anna-Karin Borg-Karlson Bjørn Bohman Philip Weinstein Paal KrokeneAbstract
No abstract has been registered
Abstract
Yunnan pine is the most important tree species in SW China in both economical and ecological terms, but it is often killed by pine shoot beetles (Tomicus spp.). Tomicus beetles are secondary pests in temperate regions and the aggressiveness of the beetles in SW China is considered to be due to the warm subtropical climates as well as the beetles’ virulent fungal associates. Here, we assessed the virulence of three blue-stain fungi (Leptographium wushanense, L. sinense and Ophiostoma canum) associated with pine shoot beetles to Yunnan pine (Pinus yunnanensis) in SW China. Following fungal inoculation, we measured necrotic lesion lengths, antioxidant enzyme activities and monoterpene concentrations in the stem phloem of Yunnan pine. Leptographium wushanense induced twice as long lesions as L. sinense and O. canum, and all three fungi induced significantly longer lesions than sterile agar control inoculations. The activity of three tested antioxidant enzymes (peroxidase, polyphenol oxidase, and superoxide dismutase) increased after both fungal inoculation and control inoculation. However, L. wushanense and L. sinense generally caused a greater increase in enzyme activities than O. canum and the control treatment. Fungal inoculation induced stronger increases in six major monoterpenes than the control treatment, but the difference was significant only for some fungus-monoterpene combinations. Overall, our results show that L. wushanense and L. sinense elicit stronger defense responses and thus are more virulent to Yunnan pine than O. canum. The two Leptographium species may thus contribute to the aggressiveness of their beetle vectors and could damage Yunnan pine across SW China if they spread from the restricted geographical area they have been found in so far.