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.
2017
Sammendrag
Production of inoculum of Colletotrichum acutatum from both previously infected and overwintered tissue, as well as newly developed plant tissue of sour cherry (Prunus cerasus), was studied in southern Norway. Plant parts were sampled from commercial, private, or research orchards, and incubated for 2 to 14 days (time depended on tissue type) in saturated air at 20°C. In early spring, abundant sporulation was found on scales of overwintered buds and shoots. A mean of 35% infected buds in four cultivars was observed, with a maximum of 72% of the buds infected in one of the samples. Over 3 years, the seasonal production of overwintered fruit and peduncles of cv. Fanal infected the previous year was investigated. In all three years, the infected plant material was placed in the trees throughout the winter and the following growing season; in two of the years, fruit and peduncles were also placed on the ground in the autumn or the following spring. Old fruit and peduncles formed conidia throughout the season, with a peak in May and June. Spore numbers declined over the season, but the decline was more rapid for plant material on the ground than in the trees. On average over 2 years, 68.7, 24.0, or 7.3% of the inoculum came from fruit placed in the trees, placed on the ground in spring, or placed on the ground the preceding autumn, respectively. The number of fruit and peduncles attached to the trees in a planting of cv. Hardangerkirsebær was followed from February to July one year, and although there was a decline over time, fruit and/or their peduncles were still attached in substantial numbers in July, thus illustrating their potential as sources of inoculum. In observations over 2 years in a heavily infected orchard of cv. Stevnsbær, 75 and 47% of flowers and newly emerged fruit, respectively, were infected. Artificially inoculated flowers and fruit produced conidia until harvest, with a peak in mid-July. It may be concluded that previously infected and overwintered, as well as newly emerged tissue of sour cherry, may serve as sources of inoculum of C. acutatum throughout the growing season.
Forfattere
Till SeehusenSammendrag
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Forfattere
Christer Magnusson Ricardo Holgado Keith Davies Deliang Peng Marte Persdatter Tangvik Ingunn BurudSammendrag
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Sascha Köpke Jürgen Kasper Peter Flachenecker Helge Meissner A. Brandt Björn Hauptmann Gabriele Bender Imke Backhus A.C. Rahn J pöttgren Eik Vettorazzi C. HeesenSammendrag
Det er ikke registrert sammendrag
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The genus Pectobacterium, which belongs to the bacterial family Enterobacteriaceae, contains numerous species that cause soft rot diseases in a wide range of plants. The species Pectobacterium carotovorum is highly heterogeneous, indicating a need for re-evaluation and a better classification of the species. PacBio was used for sequencing of two soft-rot-causing bacterial strains (NIBIO1006T and NIBIO1392), initially identified as P. carotovorum strains by fatty acid analysis and sequencing of three housekeeping genes (dnaX, icdA and mdh). Their taxonomic relationship to other Pectobacterium species was determined and the distance from any described species within the genus Pectobacterium was less than 94% average nucleotide identity (ANI). Based on ANI, phylogenetic data and genome-to-genome distance, strains NIBIO1006T, NIBIO1392 and NCPPB3395 are suggested to represent a novel species of the genus Pectobacterium, for which the name Pectobacterium polaris sp. nov. is proposed. The type strain is NIBIO1006T (=DSM 105255T=NCPPB 4611T).
Forfattere
Kris Van Looy Johan Bouma Michael Herbst John Koestel Budiman Minasny Umakant Mishra Carsten Montzka Attila Nemes Yakov A. Pachepsky José Padarian Marcel G. Schaap Brigitta Tóth Anne Verhoef Jan Vanderborght Martine J. van der Ploeg Lutz Weihermüller Steffen Zacharias Yonggen Zhang Harry VereeckenSammendrag
Soil, through its various functions, plays a vital role in the Earth’s ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.
Sammendrag
Red clover (Trifolium pratense L.) is normally a short-lived perennial with no vegetative propagation and the number of plants in the field declines rapidly. In organic farming, the amount of clover in the field is decisive for the N2 fixation and yield, the protein content and quality of the forage produced. In Nordland County (66.27°N), there is a farm with some red clover plants in more than 15 years old grassland. In the presented study we examined grassland botanical content and attempted to recognise age of red clover plants. Our hypotheses was 1) that extensive grassland management promotes self-seeding of red clover 2) self-seeding maintaining a desired content of red clover over time. In addition, we tested two harvesting regimes of the first cut for seed maturation and seed quality at two locations in Norway. Red clover plants in old swards showed very high age and a branched root system. Only very few seedlings were found in old sward suggesting that self-seeding was insignificant. Experiments with leaving the grassland after the first cut for seed production of clover failed due to poor seed maturation. Surface seeding of red clover in pure grass plots gave good results, especially with early spring seeding.
Sammendrag
Evaluating biochars for their persistence in soil under field conditions is an important step towards their implementation for carbon sequestration. Current evaluations might be biased because the vast majority of studies are short-term laboratory incubations of biochars produced in laboratory-scale pyrolyzers. Here our objective was to investigate the stability of a biochar produced with a medium-scale pyrolyzer, first through laboratory characterization and stability tests and then through field experiment. We also aimed at relating properties of this medium-scale biochar to that of a laboratory-made biochar with the same feedstock. Biochars were made of Miscanthus biomass for isotopic C-tracing purposes and produced at temperatures between 600 and 700°C. The aromaticity and degree of condensation of aromatic rings of the medium-scale biochar was high, as was its resistance to chemical oxidation. In a 90-day laboratory incubation, cumulative mineralization was 0.1% for the medium-scale biochar vs. 45% for the Miscanthus feedstock, pointing to the absence of labile C pool in the biochar. These stability results were very close to those obtained for biochar produced at laboratory-scale, suggesting that upscaling from laboratory to medium-scale pyrolyzers had little effect on biochar stability. In the field, the medium-scale biochar applied at up to 25 t C ha-1 decomposed at an estimated 0.8% per year. In conclusion, our biochar scored high on stability indices in the laboratory and displayed a mean residence time > 100 years in the field, which is the threshold for permanent removal in C sequestration projects.