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.
2024
Abstract
Tip rot of carrot significantly reduces root quality and contributes to the high-level rejection during sorting and packaging in Norway. The rot can be dry, or wet, and vary in colour from light brown to dark brown. Diagnosis of a plant disease involves close examination of the symptoms, detection and identification of the causal agent(s), and confirmation of pathogenicity. The objective of this study was to identify the causal agent(s) of tip rot in carrot. Fungi and bacteria were isolated from multiple carrots with tip rot symptoms and used for inoculation of healthy carrots to determine pathogenicity and also for DNA extraction, sequencing of commonly used genes for identification and barcoding genes and DNA metabarcoding. For isolation and inoculation, we developed a method allowing individual carrots to remain upright without touching each other within an incubation box. For morphological identification of causal agents, we found that a combination of methods such as isolation on potato carrot agar, disinfection of infected tissue followed by moist incubation, and inoculation followed by incubation at room temperature for 24 h, and then at 0-6°C were optimal methods for the identification of tip rot pathogens of carrot. Based on the combination of molecular and morphological identification methods, we found that tip rot of carrots is a disease complex caused by several fungi but principally Mycocentrospora acerina and Cylindrocarpon destructans. Diagnosis of postharvest diseases is often a complex problem, and this research demonstrates that a combination of methods is a useful approach. Furthermore, the study indicated that the common approach of trying to associate a disease with a single causal agent does not work for all postharvest diseases. The possibility of multiple causal agents and predisposing factors must be considered, and we should be cautious not to jump to a hasty decision.
Authors
Melissa MagerøyAbstract
No abstract has been registered
Authors
Melissa MagerøyAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Mingkai Jiang Kristine Y. Crous Yolima Carrillo Catriona A. Macdonald Ian C. Anderson Matthias M. Boer Mark Farrell Andrew N. Gherlenda Laura Castañeda-Gómez Shun Hasegawa Klaus Jarosch Paul J. Milham Rául Ochoa-Hueso Varsha Pathare Johanna Pihlblad Juan Piñeiro Jeff R. Powell Sally A. Power Peter B. Reich Markus Riegler Sönke Zaehle Benjamin Smith Belinda E. Medlyn David S. EllsworthAbstract
The capacity for terrestrial ecosystems to sequester additional carbon (C) with rising CO2 concentrations depends on soil nutrient availability1,2. Previous evidence suggested that mature forests growing on phosphorus (P)-deprived soils had limited capacity to sequester extra biomass under elevated CO2 (refs. 3,4,5,6), but uncertainty about ecosystem P cycling and its CO2 response represents a crucial bottleneck for mechanistic prediction of the land C sink under climate change7. Here, by compiling the first comprehensive P budget for a P-limited mature forest exposed to elevated CO2, we show a high likelihood that P captured by soil microorganisms constrains ecosystem P recycling and availability for plant uptake. Trees used P efficiently, but microbial pre-emption of mineralized soil P seemed to limit the capacity of trees for increased P uptake and assimilation under elevated CO2 and, therefore, their capacity to sequester extra C. Plant strategies to stimulate microbial P cycling and plant P uptake, such as increasing rhizosphere C release to soil, will probably be necessary for P-limited forests to increase C capture into new biomass. Our results identify the key mechanisms by which P availability limits CO2 fertilization of tree growth and will guide the development of Earth system models to predict future long-term C storage.
Authors
Carl Frisk Godfrey Philliam Apangu Geoffrey M. Petch Simon Creer Mary Hanson Beverley Adams-Groom Carsten Ambelas SkjøthAbstract
No abstract has been registered
Abstract
Manures are potentially both a source of nutrients for plants and a source of pollution. Manure produced depends on animal densities and type rather than plants need. Over time, this has enriched soils with P and organic N. The challenge is maximal nutrient recycling and minimal pollution from the manure used for plant production. To investigate the optimal seasonal distribution of manure, field experiments were carried out in 2022 and 2023 on grassland in three agricultural regions in Norway. Three distributions of cattle slurry at 30 kg P ha–1 were tested, with or without additional N fertilizer. These were compared with control treatments without slurry: no fertilizer, and compound NPK and NK fertilizers. Different distributions had little effect on grass yield and uptake of P and N. Applying a larger proportion of manure in spring increased grass yield, while additional mineral N fertilizer significantly increased yield but reduced N use efficiency. Slurry alone gave a P surplus, while added mineral N fertilizer allowed a net mining of P. There seems therefore to be a trade-off regarding whether the efficient use of N or P is to be prioritized. The decision should likely depend on required yields as well as local pollution risks.
Abstract
No abstract has been registered
Abstract
Eucalyptus plantations are a notable source of income for smallholders and private landowners in Thailand. The main uses of eucalyptus are for energy purposes and as pulpwood, sawn timber, and veneer. Among private eucalyptus forest owners there is a need for decision support tools that can help in optimizing tree bucking, according to the available properties of the site and bucking patterns. The precise characterization of plantation properties is key to delivering appropriate timber assortment to markets and optimizing timber value. Our study has developed and tested dynamic and linear programming models for optimizing the tree bucking of eucalyptus trees. To achieve this, tree taper curves for use in volumetric models were defined for optimization. Our results indicate that both the tree spacing and the increment of diameter of breast height are significant factors when estimating profitability. The income would be significantly higher if bucking timber in different assortments were used, instead of the current approach of selling as bulk based on mass. For implementation, we created a free mobile application for android phones (EVO—eucalyptus value chain optimization) to utilize the study results at the grass root-level.
Abstract
Lingonberry (Vaccinium vitis-idaea L.) grows in a range of nature types in the boreal zone, and understanding factors affecting the abundance of the plant, as well as mapping its spatial distribution, is important. The abundance of the species can be an indicator of ecosystem changes, and lingonberry can also be a source for commercial utilisation of berry resources. Using country-wide data from 6404 field plots of the Norwegian national forest inventory (NFI), we modelled the relationship between lingonberry cover and airborne laser scanning (ALS) and satellite metrics and bioclimatic variables describing the forest structure, terrain, soil properties and climate using a generalised mixed-effects model with a quasipoisson distribution. The validation carried out with an independent set of 2124 NFI plots indicated no obvious bias in predictions. The most important predictors were found to be interactions between dominant tree species, stand basal area and latitude, as well as the reflectance in the near-infrared band from Sentinel-2 satellite imagery, the dominant height based on the ALS variable and the long-term mean summer (June–August) temperature. The results provide an indicator of the effects of global warming, as well as the possibility of giving forest management prescriptions that favour lingonberry and locating the most abundant lingonberry sites in Norwegian forests.