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.
2010
Sammendrag
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Forfattere
Eirik NordhagenSammendrag
Det er ikke registrert sammendrag
Forfattere
Eivind Vangdal Sigrid Flatland Ingvild Kristine MehlSammendrag
Det er ikke registrert sammendrag
Forfattere
Eivind Vangdal Sigrid Flatland Ingvild MehlSammendrag
Experiments with foliar fertilization in plums have been performed in Western Norway. In one experiment possible effects of extra magnesium, potassium and the combination of both magnesium and potassium were compared to control trees given a standard foliar fertilization programme. In the other experiment the standard foliar fertilization programme was compared to control trees given soil fertilization only. Yield and fruit size as well as major fruit quality factors were registered. Leaves and fruit were analysed for major nutrients. No strong effects of foliar application with magnesium and potassium on fruit quality were observed. The treatments did not affect the content of major nutrients in leaves and fruit to such an extent that significant effects on fruit quality would be expected. The foliar fertilization programme tended to delayed maturation of the fruit as the fruit were greener and with less blush colour, firmer and had lower content of soluble solids and higher content of titratable acidity. The changes in separate quality factors were, however, not statistically significant. The foliar fertilized trees tended to have higher content of nitrogen in the leaves and lower content of the other major nutrients.
Sammendrag
The effect of potential resistance inducing chemicals on disease development of Fusarium head blight was studied in winter wheat (Triticum aestivum L.). As a pre-screening test, the effect of different treatments on development of Microdochium majus (syn. Microdochium nivale var. majus) was studied in detached leaves. Based on these tests, DL-3-aminobutyric acid, Bion (benzo-(1,2,3) thiadiazole-7-carbothioic acid S-methyl ester), and a foliar fertilizer containing potassium phosphite were selected for further studies. Greenhouse-grown winter wheat was sprayed with aqueous solutions of the potential resistance inducers 7 days prior to Fusarium culmorum point inoculation of the heads. Disease development was registered as number of bleached spikelets per inoculated spike. Spraying plants with the foliar fertilizer reduced the disease severity of F. culmorum by up to 40%. A reduced disease development of M. majus was also observed in detached leaves pre-treated with the foliar fertilizer. When the foliar fertilizer was added to the growth medium, a reduced in vitro growth of M. majus and F. culmorum was observed, indicating that the effect on disease development is at least partly due to a fungistatic effect. No significant reduction in disease development was observed in wheat pre-treated with DL-3-aminobutyric acid or Bion, although these compounds tended to reduce disease development, especially when applied in combination with other potential resistance inducers. We conclude that spraying winter wheat with a solution containing potassium phosphite can reduce development of M. majus and F. culmorum.
Sammendrag
The leaf blotch complex is one of the most important yield limiting disease on wheat in Norway. It is caused by three pathogens, Septoria tritici ( Mycosphaerella graminicola), Stagonospora nodorum ( Phaeosphaeria nodorum), and Drechslera tritici-repentis (Pyrenophora tritici-repentis). The symptoms of each of the pathogens are similar and easily confused with leaf senescence, making it difficult to assess the true disease severity and thus hampering breeding for leaf blotch resistance. To reduce unnecessary pesticide use and the risk of pesticide resistance developing in the fungal populations, timing of disease control measures are based on forecasting models. The degree of a leaf blotch epidemic is determined by initial inoculums, precipitation, temperature, time, availability of susceptible hosts and the degree of susceptibility. During the last 20 years, the start of the growing season as marked by a soil temperature of 5C, has advanced by 1-1.5 days per year (Rafoss, 2009), indicating an increase in the length of growing seasons. The trend for warmer and wetter growing seasons is predicted to continue in the future. It is of high relevance to the wheat industry to understand the impact of these changes on leaf blotch diseases in the field to optimize disease forecasting and management. We have collected data on leaf blotch severity in the field and weather conditions at different wheat growing areas in Norway over the last 10 years. Based on this data, we do not see a general increase in disease severity over the last decade. However, the data shows that there are local shifts in maximum disease severity; areas that support high disease severity and areas that support very little. Given the amount of initial inoculum and availability of susceptible hosts are comparable between the different wheat growing areas, the local climate per site becomes the determining factor for the epidemic. We studied the effect of relatively small, local differences in precipitation, temperature, and start of growing season on leaf blotch development in the field. The analysis of local shifts in climatic conditions and their relation to disease development allows us to estimate the effect of the changing climate on leaf blotch disease in the future.
Forfattere
Arnstein Staverløkk May-Guri Saethre Trond HofsvangSammendrag
The history of Harmonia axyridis and a summary of surveillance and research in Norway till June 2009 are given. H. axyridis was assessed as a potential bio-control agent for use in Norwegian greenhouses in 2001. The risk of establishment outdoors was assessed too high and no permission was given. The first record in Norway was in 2006 when one adult was found on Thuja sp. imported from the Netherlands. In late 2007 and throughout 2008 adults were found indoors/outdoors at several locations in the Oslo-area. Establishment outdoors became evident. Observations in Aust-Agder, Vestfold and Trondheim revealed further spread/introduction to new areas. The bioclimatic potential of H. axyridis was assessed in 2007 by the aid of CLIMEX using national agrometeorological data, showing that suboptimal microclimates for the species can be found in the coastal areas of the south. In late 2008 a web-site was launched aiming to engage the public to submit observations on-line and has contributed to monitor development of the species across the country. Competition experiments with H. axyridis and Coccinella septempunctata in 2008/2009 showed that only H. axyridis eggs and larvae survived when the two species were mixed.
Sammendrag
In European forests, standing stocks are currently higher than ever during the last decades, in part due to reduced logging or the abandonment of agricultural land. However, data from intensive monitoring plots reveal an increased growth even without direct human intervention.We used a set of 363 plots from 16 European countries to investigate the influence of environmental factors on forest growth: nitrogen, sulphur and acid deposition, temperature, precipitation and drought, for Norway spruce, Scots pine, common beech and European as well as sessile oak.We used existing information on site productivity, stand age and stand density to estimate expected growth. Relative tree growth, i.e., the ratio between actual growth within a five-year period and expected growth, was then related to environmental factors in a stepwise multiple regression.The results consistently indicate a fertilizing effect from nitrogen deposition, with roughly one percent increase in site productivity per kg of nitrogen deposition per ha and year, or 20 kg C fixation per kg N deposition. This was most pronounced for plots having soil C/N ratios above 25. We also found a positive albeit less clear relationship between relative growth and summer temperatures.From the study, we cannot conclude on any detrimental effects on growth from sulphur and acid deposition or from drought periods. A very recent study from the U.S., comprising 4800 plots and 24 tree species, confirms our results. However, we also show that the magnitude of N deposition effects on global forest C balance is currently a highly controversial matter, and comment on this debate. http://www.cef-cfr.ca/uploads/Colloque/Programme10_5.pdf
Forfattere
Adam ParuchSammendrag
Det er ikke registrert sammendrag
Forfattere
Lampros LamprinakisSammendrag
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