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.
2000
Forfattere
S. Rekolainen V. Gouy R. Francaviglia Ole Martin Eklo I. BärlundSammendrag
The GLEAMS modell predicts runoff, percolation and soil and chemical losses at the edge of a field and from the root zone. The objective of this study was to test the performance of the GLEAMS model against three observed data sets from different parts of Europe. Three users tested the model independently, i.e. parametrized the model without discussion with the other users. Both uncalibrated and calibrated results are presented. Furthermore, the pesticide sub-model was parametrized according to proposals of the supplier of the measurement data. The test was focused on soil moisture, tractor (bromide) and pesticide movements in soil columns. The results show that GLEAMS soil moisture predictions appear to react too rapidly to wet and dry periods, resulting in a rapid change of soil moisture between field capacity and wilting point. Incomplete simulation of soil water dynamics seems to be the main reason for underestimation of tracer movement in soil. In addition, mismatches in soil pesticide concentrations might be caused by incorrect prediction of degradation processes. The results of the independent users different considerably from each other, both in uncalibrated and in calibrated results, due to different interpretation of the measured data.
Forfattere
Ole Martin EkloSammendrag
Testing of pesticide-leaching models is important in view of their increasing use in pesticide registration procedures in the European Union. This paper presents the methodology and major conclusions of a test of pesticide-leaching models. Twelve models simulating the vertical one-dimensional movement of water, solute, heat, and, in particular, pesticides, through the soil profile were used by 36 different modellers. The adopted modelling codes differ in terms of modelling concepts and modelling hypothesis. Modellers were affiliated to industry and to the scientific community as well. Four quality datasets were identified to perform the analysis. The dataset includesdfield and lysimeter data, collected in the Netherlands, Germany, Italy and the UK. As well, non-structured as structured soils were available in the dataset. To elucidate the ability to model correctly water transport, solute transport, heat transport and pesticide transport in soils, a stepwise evaluation approach was followed. Splitting up the experimental dataset enabled ut to quantify the calibration capability and the prediction capability to the models. The simulations were performed by different model users enabling us also to characterise output variability in terms of user dependent interpretation of the model input and parameters. Recommendations are formulated for improving the quality of modelling dataset, and the process description of water, solute, and heat transport in a pesticide-leaching model, plus the process description of pesticide fate. Application of the principles of good modelling practice (GMP) is briefly described
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Arild SlettenSammendrag
Det er ikke registrert sammendrag
Forfattere
P. Risøen May Bente Brurberg V. Eijsink I. NesSammendrag
PUBMED eller ISI
Forfattere
Helge BonesmoSammendrag
The relationship between regrowth rates and the content of water-soluble carbohydrates in stubble (WSC) and percentage non-elongated tillers (PNT) was studied in timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis Huds.) cut at different phenological stages. Single plants were grown in pots and cut outdoors and then regrown under controlled climatic conditions. The data for the dry matter production during the following three weeks were fitted to an expolinear growth equation to determine an initial maximum relative regrowth rate (Rm) and a daily maximum regrowth rate (Cm). Cm appeared to be positively correlated to PNT in both species, whereas Rm was increased with increasing WSC. For regrowth after later cuts of meadow fescue there was a positive contribution to Rm by PNT.
Forfattere
Lars Nesheim J. BrønstadSammendrag
A field experiment was carried out on thirty locations to examine whether commercial hybrids of Festuca and Lolium (festulolium) do have a better winter hardiness than varieties of perennial ryegrass under Norwegian climatic conditions. In the first year the ground cover in spring was much lower for the festulolium `Paulita" than for the standard timothy/meadow fescue mixture, particularly for sites in Eastern Norway. There were no significant differences in total DM yield in the first year between the standard mixture and the varieties of festulolium in Eastern and Western Norway, whereas `Paulita" gave about 10% higher yield than the control in Central Norway. In the third year both the ground cover and the DM yields were significantly lower for the festulolium and the ryegrasses than for meadow fescue and the mixture of timothy and meadow fescue. Particularly at the first cut the content of water-soluble carbohydrates were much higher in festulolium and ryegrasses than in timothy and meadow fescue. For neutral detergent fibre (NDF) the opposite picture was found.
Sammendrag
Preharvest cuticular fractures in sweet cherry fruits have been suggested to facilitate pathogen invasion, and a method to classify amount of cuticular fracturing into five categories (1 = no visible fractures, 5 = severe fracturing) has previously been proposed (18). Sweet cherry fruits of the four cultivars Early Burlat, Lapins, Van, and Vista were sorted into these five categories of cuticular fracturing and inoculated with conidial suspensions of either Botrytis cinerea or Monilinia laxa. After incubating the fruits at 20°C and 100% RH for 4 - 7 days, they were assessed for visible fungal growth. Due to quiescent infections of M. laxa, fruits treated with B. cinerea developed more brown rot than grey mold. However, a significant linear relation (p < 0.05) between the amount of cuticular fracturing and fungal infections was obtained in 5 of 7 trials with B. cinerea and in 2 of 4 trials with M. laxa, indicating that fungal infections in sweet cherry fruits may be facilitated by cuticular fractures. Independent of cultivar and year, a significant linear relation was found between the category of cuticular fracturing and percentage of infected fruits after inoculation with both B. cinerea and M. laxa, and in control fruits (p = 0.0001, p = 0.0183, and p = 0.0182, respectively). This is the first report quantifying an increase in fungal infection with increasing amount of cuticular fracturing. The mean difference in fruit rot (%) ± std.dev. between fruits in fracturing categories 1 and 5, expressed as the linear contrast of amount of fruit rot in category 5 minus amount of fruit rot in category 1, was 37.2 ± 7.4 (p = 0.0001), 35.4 ± 11.0 (p = 0.0022), 17.0 ± 6.7 (p = 0.0135), and 29.8 ± 4.7 (p = 0.0001), after treatments with B. cinerea, M. laxa, water control, and for all data pooled, respectively
Forfattere
D. Gaudet A Laroche Åshild Ergon J. MullinSammendrag
Exposure of winter wheat to pre-hardening (20°C) and hardening (2°C) growth temperatures for different intervals under controlled environment conditions affected the nature and quantity of simple and complex carbohydrates in six cultivars differing in resistance to snow mould. The highest levels of total simple sugars were observed following exposure of plants to hardening temperatures for one week followed by a stabilisation or decline following 3 or 6 weeks exposure to 2°C. Fructan levels increased rapidly following 3 and 6 weeks exposure to 2°C. In younger plants grown for 2 weeks at 20°C and hardened for 6 weeks, 10-37% (ave. 20%) of crown dry weights existed as fructans compared with 24-47% (ave. 39%) in crowns of older plants grown for 6 weeks at 20°C and similarly hardened. Fructans comprised 75-82% of all soluble carbohydrates regardless of plant age prior to hardening. The average degree of polymerization increased from DP3-4 following one week hardening to DP9-11 following 6 weeks hardening and was significantly higher in hardened older plants than in hardened young plants. These results are discussed in relation to the form of snow mould resistance that increases with plant age in winter cereals.
Forfattere
D. Gaudet A. Laroche M. Frick J. Davoren B. Puchalski Åshild ErgonSammendrag
The pattern of expression of the pathogenesis-related (PR) proteins PR-1, chitinase, b-1,3-glucanase, and peroxidase, and phenylalanine ammonia lyase (PAL) transcripts was studied in five winter wheat cultivars differing in resistance to snow mould, under controlled conditions following growth at 20°C, during hardening at 2°C and dehardening at 20°C. The expression of these transcripts was also studied in two cultivars of winter wheat under natural conditions during autumn, winter, and early spring of 1997-98 at a field site in Lethbridge. The relative abundance of transcripts was similar in both the field and controlled environment studies: chitinase was the most abundant transcript followed by PAL, b-1,3-glucanase, PR-1 and peroxidase. Under field conditions, all PR-protein transcripts exhibited the same basic pattern of expression during the autumn, winter and spring sampling dates; transcripts were expressed during the late autumn, reached high levels by mid-winter, then dcreased before reaching maximum leves during the spring. Conversely, PAL expression was low or absent in autumn, reached the highest levels by mid-winter, and then gradually decreased during the spring. Under controlled environment conditions, transcripts encoding for PAL and the PR-proteins, except chitinase, were constitutively expressed to varying extents in the unhardened treatments. The general pattern of expression fell into two groups: (1) transcripts of chitinase, b-1,3-glucanase, and PAL, were weakly expressed in the unhardened treatments, strongly up-regulated following exposure to hardening conditions, and disappeared or remained stable following dehardening; and, (2) PR-1 and peroxidase transcripts were down-regulated upon initial exposure to hardening, increased slightly following prolonged exposure to hardening conditions, and remained stable during dehardening. Under controlled conditions, the pattern of expression of any of the PR-proteins did not appear to be associated with known genotypic levels of snow mould resistance among cultivars but, under field conditions, expression levels were generally higher for all PR-proteins in the snow mould resistant cultivar, CI14106 than in the moderately susceptible cultivar, Norstar. These results demonstrate that different PR-protein and PAL transcripts in winter wheat are expressed in the field throughout the winter and are differentially induced in response to exposure of plants to low, hardening temperatures under both field and controlled environment conditions.