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.
2018
Forfattere
Victor Rueda-Ayala Hella Ellen Ahrends Stefan Siebert Thomas Gaiser Hubert Hüging Frank EwertSammendrag
Impacts of nutrient supply and different cultivars (genotypes) on actual yield levels have been studied before, but the long-term response of yield trends is hardly known. We present the effects of 24 different fertilizer treatments on long-term yield trends (1953–2009) of winter wheat, winter rye, sugar beet and potato, with improved cultivars changing gradually over time. Data was obtained from the crop rotation within the long-term fertilization experiment at Dikopshof, Germany. Yield trends were derived as the slope regression estimates between adjusted yield means and polynomials of the first year of cultivation of each tested cultivar, when tested for more than two years. A linear trend fitted best all data and crops. Yields in highly fertilized treatments increased linearly, exceeding 0.08 t ha−1 a−1 for both, winter wheat and winter rye, and ≥0.30 and ≥0.20 t ha−1 a−1 for sugar beet and potato fresh matter yields. Yield trends of winter cereals and sugar beet increased over time at N rates ≥40 kg ha−1 a−1, being 0.04–0.10 t ha−1 a−1 for cereals and 0.26–0.34 t ha−1 a−1 for sugar beet, although N rates >80 kg ha−1 a−1 produced a stronger effect. Nitrogen was the most influential nutrient for realisation of the genetic yield potential. Additional supply of P and K had an effect on yield trends for rye and sugar beet, when N fertilization was also sufficient; high K rates benefited potato yield trends. We highlight the importance of adequate nutrient supply for maintaining yield progress to actually achieve the crop genetic yield potentials. The explicit consideration of the interaction between crop fertilization and genetic progress on a long-term basis is critical for understanding past and projecting future yield trends. Long-term fertilization experiments provide a suitable data source for such studies.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Nina JohansenSammendrag
Thrips setosus er en polyfag trips med opprinnelse i Øst-Asia. Arten ble første gang påvist i Europa i 2014. Da ble tripsen påvist hos en produsent av hortensia i Nederland, og påfølgende undersøkelser konkluderte med at tripsen allerede var etablert i flere områder. De siste årene har T. setosus spredt seg til England, Tyskland, Frankrike og Kroatia. Arten ble satt på EPPO Alert list i 2014, og EPPO anbefaler at det blir satt i verk tiltak for å stanse videre spredning.......
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Habtamu AlemSammendrag
Previous studies estimating TFP and its components have been criticized for not considering farm heterogeneity in their model. Moreover, the studies focused on the technical evaluation of a sector. However, the technical evaluation alone reveals how well farmers use the physical production process. There is a need to closely examine the cost efficiency of the farmers. In this study, we used a cost function (dual) approach to facilitating the decomposition and estimation of TFP components. Using a translog stochastic cost function, we estimated the level and source of productivity and profitability change for crop producing family firms in Norway. We used the true random effect to account for farm heterogeneity. The analysis is based on 23 years unbalanced panel data (1991-2013) from 455 crop- producing firms with a total of 3885 observations. The result indicates that average annual productivity growth rate in grain and forage production was - 0.11 % per annum during the period 1991-2013. The profit change was 0.14 % per annum.
Forfattere
Knut ØistadSammendrag
Det er ikke registrert sammendrag
Forfattere
Tove Vaaje-KolstadSammendrag
Det er ikke registrert sammendrag
Sammendrag
Effects of climatic factors and material properties on the development of surface mould growth on wooden claddings were investigated in a laboratory experiment. Specimens of aspen (Populus tremula), Siberian larch (Larix Sibirica), American white oak (Querqus alba), Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and thermally modified pine were incubated in eight climatic chambers at specified wetting periods (2 or 4 h per day), relative humidity (58–86%) and temperature conditions (10–27°C). Surface mould growth was assessed weekly for 13 weeks, and the results were evaluated statistically using Generalized Estimating Equations logistic regression models. All tested climatic factors had significant effects on the mould growth, and there were significant differences between the materials. The ranking of the materials varied with temperature and over time. Aspen, pine sapwood and oak were overall most susceptible to mould growth, and thermally modified pine least susceptible. There were significant differences between sapwood and heartwood for pine and spruce. The effect of density was tested on the spruce heartwood material, but was not found to be significant. The results can be used to further develop prediction models for mould growth on wooden claddings.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Ellen Johanne SvalheimSammendrag
Det er ikke registrert sammendrag