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.
2020
Forfattere
Mohamed Ibrahim Mohamed Abdelhalim May Bente Brurberg Ingerd Skow Hofgaard Odd Arne Rognli Anne Marte TronsmoSammendrag
Microdochium majus and Microdochium nivale cause serious disease problems in grasses and cereal crops in the temperate regions. Both fungi can infect the plants during winter (causing pink snow mould) as well as under cool humid conditions during spring and fall. We conducted a pathogenicity test of 15 M. nivale isolates and two M. majus isolates from Norway at low temperature on four different grass cultivars of Lolium perenne and Festulolium hybrids. Significant differences between M. nivale isolates in the ability to cause pink snow mould were detected. The M. nivale strains originally isolated from grasses were more pathogenic than isolates from cereals. The genetic diversity of M. nivale and M. majus isolates was studied by sequencing four genetic regions; Elongation factor-1 alpha (EF-1α), β-tubulin, RNA polymerase II (RPB2) and the Internal Transcribed Spacer (ITS). Phylogenetic trees based on the sequences of these four genetic regions resolved M. nivale and M. majus isolates into separate clades. Higher genetic diversity was found among M. nivale isolates than among M. majus isolates. M. nivale isolates revealed genetic differences related to different host plants (grasses vs. cereals) and different geographic regions (Norway and UK vs. North America). Sequence results from the RPB2 and β-tubulin genes were more informative than those from ITS and EF-1α. The genetic and phenotypic differences detected between Norwegian M. nivale isolates from cereals and grasses support the assumption that host specialization exist within M. nivale isolates.
Forfattere
Sille Rebane Kalev Jõgiste Andres Kiviste John A. Stanturf Marek MetslaidSammendrag
A large area of Estonian hemiboreal forest is recovering from clear-cut harvesting and changing carbon (C) balance of the stands. However, there is a lack of information about C- source/sink relationships during recovery of such stands. The eddy covariance technique was used to estimate C-status through net ecosystem exchange (NEE) of CO2 in two stands of different development stages located in southeast Estonia in 2014. Measured summertime (June–September) mean CO2 concentration was 337.75 ppm with mean NEE −1.72 µmol m−2 s−1. June NEE was −4.60 µmol m−2 s−1; July, August, and September NEE was −1.17, −0.77, and −0.25 µmol m−2 s−1, respectively. The two stands had similar patterns of CO2 exchange; measurement period temperature drove NEE. Our results show that after clear-cutting a 6-year-old forest ecosystem was a light C-sink and 8-year-old young stand demonstrated a stronger C-sink status during the measurement period.
Forfattere
Eva Narten HøbergSammendrag
Det er ikke registrert sammendrag
Vitenskapelig – Performance of the Norwegian dairy farms: A dynamic stochastic approach
Habtamu Alem
Forfattere
Habtamu AlemSammendrag
From a theoretical perspective, it is well stated that the farm's decision on the use of inputs depends on the farmer's ability to make an efficient decision over time. The existing literature in performance analysis of the dairy farms based on static modeling and thus ignores the inter-temporal nature of production decisions. This paper aims to construct a dynamic stochastic production frontier incorporating the sluggish adjustment of inputs, to measure the performance of dairy farms in Norway. The empirical application focused on the farm-level analysis of the Norwegian dairy sector for 2000- 2018. The dynamic frontier estimated using the system Generalized Method of Moments estimator. The analysis shows that the static model in the previous studies underestimates the performance of the dairy farms.
Sammendrag
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Sammendrag
This paper analyses two strategies to reduce the use of pesticides in grain production. We study Norwegian farmers’ willingness to voluntarily forego income by reducing pesticide use as well as their responses to a doubling of the pesticide price (through increased pesticide taxes). We use mixed methods including an experiment, a survey and focus group discussions. The experiment shows that most farmers are willing to sacrifice some income to reduce environmental risks by using less pesticide. According to the survey, they are, at the same time, relatively insensitive to a 100% price increase on herbicides and fungicides. While the response to the price increase probably would have been stronger if differentiated between chemicals, our research indicates potential benefits from supporting voluntary action. Value orientations and agronomic conditions influence the stated responses in both circumstances. Respondents emphasizing environmental values are more willing to voluntarily reduce pesticide use and show a greater response to the economic incentive than farmers emphasizing economic outcome and issues such as clean fields. A hypothesized willingness to reduce pesticide use voluntarily to strengthen the reputation of the sector was, however, rejected. Farmers appear to have few alternatives to pesticides, but increased knowledge about the alternatives that do exist, seems able to promote some change. Our findings suggest that the extension service should put greater emphasis on these options, even if they may have negative effects on income.
Forfattere
Tor J. Johansen Anne-Marie Cortesero Michael T. Gaffney Richard Meadow Quentin Schorpp Rosemary CollierSammendrag
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Sammendrag
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Sammendrag
Phosphorus retention and bank erosion was investigated in two types of buffer zones in cereal fields in Norway: zones used for grass production and zones with natural vegetation. Farmers’ views on the two types of buffer zones were collected through questionnaires and indepth interviews. Our results indicate that the grassed buffer zones had higher levels of plant-available phosphorus and lower infiltration rates than the natural ones. Bank erosion was higher in zones with grass production than those with trees. Interviews with farmers revealed diverging opinions on the zones. Most farmers were sceptical to natural vegetation with trees, whereas farmers who had already planted trees in the riparian zones were generally satisfied. Buffer zones can have many different functions, and we conclude that a holistic approach is needed when assessing the usefulness of this measure, taking into account water quality, biodiversity and the production of food, fodder and biomass.
Forfattere
Ranjana Pathak Åshild Ergon Arne Stensvand Hans Ragnar Gislerød Knut Asbjørn Solhaug Lance Cadle-Davidson Aruppillai SuthaparanSammendrag
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