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.
2006
Forfattere
Birgitte Henriksen Lars ReitanSammendrag
Dyrking av blandinger av sorter med ulik grad av sjukdomsresistens mot f.eks. mjøldogg og rust, er i mange undersøkelser vist å gi redusert angrep av disse sjukdommene. Det er tidligere ikke studert hvorhvidt sortsblandinger kan påvirke forekomst av Fusarium i aks og korn. Høsta korn fra to sortblandingsforsøk i 2005 med tre byggsorter dyrket sammen i ulike to-sortskombinasjoner og i renbestand, ble undersøkt for angrep av Fusarium i høsta korn. Det ene feltet hadde svært høyt angrep av Fusarium, og ingen forskjeller kunne observeres mellom sorter eller mellom ulike sortsblandingskombinasjoner. I det andre feltet varierte angrepet mellom sorter og mellom sorter i renbestand og sortsblandinger. Infeksjon av Fusarium i en blanding av to sorter var redusert ned mot nivået i sorten som hadde lavest Fusariuminfeksjon i renbestand. Resultatene er foreløpige og undersøkelsen vil bli gjentatt med korn fra samme type forsøk i 2006.
Sammendrag
The semi-natural salt marshes in Norway have probably been used as pastures for cattle, horses and sheep, as long as there have been domestic animals in Norway. Due to regular flooding, the salt marshes are nutrient rich and high production is maintained without fertilizing. Today, the biodiversity of the salt marshes is threatened due to land drainage, cultivation, development, and pollution, or due to cessation of grazing and overgrowth. The results of this study clearly show that the semi-natural vegetation types found in 1974 and in 1985, and the wading bird population found in 1975/1976, are drastically reduced due to cessation of grazing. To re-establish and maintain some of the salt marshes and the biodiversity, restoration and management is necessary.
Sammendrag
In the Nordic countries several composting plants for source separated organic household waste (SSOW) have experiences problems with establishment of high-rate respiration processes. The problems with start-up of the high-rate composting phase can be related to sensitivity of the thermophilic microflora to low pH in the composting material. Low pH is caused by high content of organic acids produced by fermenting microorganisms in the waste. In our studies we investigated the effect of different ratio of SSOW mixed with bulking agent in the development of short organic acid content and the shift from a fermentative to aerobic bacteria population during composting.
Forfattere
Lars Nesheim Gustav FystroSammendrag
The resources of rock phosphates are limited. Common use as P fertiliser has to be considered, both in environmental and economical perspectives. Applied superphosphate in many former plant nutrient investigations ruled out the possibility of consistent discussions of the separate S and P effects. The objective of the presented field experiments was to test how plant growth in grassland relates to proposed critical values of herbage P to N relationships. Three field trials were established on soils low in P. Five levels of P fertilisation (0, 5, 10, 20 and 50 kg P ha-1 yr-1) and two levels of N (normal and 50 % of normal) were applied. The trials were harvested in two subsequent years. Plant P uptake on unfertilised plots was higher then expected, and uptake of applied P was lower. Thus, the relation between relative dry matter yield and P/N in plants was not as detailed examined as planned, however, the yield decrease following low P/N was in accordance to our hypothesis. When 20 kg P ha-1 was applied only 14 % was found in the harvested material.
Sammendrag
Total anti-oxidant capacity (TAC) and the contents of mono- and disaccharides, and organic acids were determined in strawberry fruit from ten genotypes sampled from eight experimental sites in Norway in 2002 and 2003.The difference between genotypes was significant for all recorded traits, and it appeared possible to select for all traits in breeding programmes. On average, the Norwegian bred cultivar `Carmen" had a TAC of 30.07 mmol kg"1 fresh weight (FW), compared to 23.16 mmol kg"1 FW in the standard cultivar `Korona". TAC was negatively correlated with fruit size, rainfall and leaf surface humidity, but was positively correlated with the minimum temperature on the day prior to sampling. Mono- and di-saccharide contents were negatively correlated with both minimum and maximum temperatures, and with wind velocity. It was confirmed that the sugars:organic acids ratio was inversely related to the maximum temperature on the day before harvest, which supports anecdotal claims that strawberries grown in northern areas have, on average, better flavour.
Sammendrag
A commercial extract of neem (NeemAzal-T) and a simple extract of pulverised seeds extracted in warm water were tested against the cabbage pest Mamestra brassicae L. Oviposition was reduced to half the number of eggs per plant by the neem treatment. The number of eggs that hatched was not affected by the neem treatment, but development of these larvae was strongly inhibited and all larvae in the neem treatment died within two weeks without reaching 2nd instar. The concentration of the active ingredient azadirachtin-A (the azadirachtin component in NeemAzal-T) needed to protect plants from damage by 2nd instar larvae was 8 "g ml"1. The lethal doses for 2nd instar larvae were 6.2 and 17.2 "g ml"1 for LC50 and LC95, respectively. NeemAzal-T protected plants from damage for at least three weeks if applied before oviposition, or at least two weeks if applied against 2nd instar larvae. In these studies, neem inhibited oviposition, larval development and feeding, and greatly increased mortality.
Sammendrag
Zero-valent iron improves the transformation of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites in aged and highly contaminated lake sediment under biotic conditions. The addition of Feº has a strong effect on transformation rates at 22 ºC and 9 ºC, the most enhanced degradation being obtained for DDT and DDOH [2,2-bis(pchlorophenyl) ethanol]. At 22 ºC and 10 weeks´incubation, the DDT concentration is reduced from 2.75 lmol g-1 (974 mg kg-1) to 0.98 lmol g-1 (346 mg kg-1) and 1.98 lmol g-1 (702 mg kg-1) in samples with and without the addition of iron, respectively. After 40 weeks` incubation these concentrations have further decreased to 0.19 lmol g-1 (66 mg kg -1) and 0.74 lmol g-1 (264 mg kg-1).There is no significant transformation of any of the compounds at 9 ºC without the addition of Feº. In the presence of iron, however, DDT is reduced to 1.25 lmol g-1 (442 mg kg-1) within 40 weeks´ incubation. This study demonstrates the ability of adapted microorganisms to transform DDT under elevated temperatures in original, aged sediments, and also the stimulating effect of zero-valent iron, which is significant even at low temperatures.
Forfattere
Helge Bonesmo Stein Rune Karlsen Anne Kjersti Bakken Kjell-Arild HøgdaSammendrag
Seasonal growth and minimum and maximum N content of timothy swards were calculated on the basis of soil and weather data for five sites and five years in Norway. The five sites covered a wide range of the climatic variation among regions with agricultural grass production. For each of the sites and years the daily estimated grass growth was related to the Normalized Difference Vegetation Index (NDVI) obtained from the MODIS satellite data, and on pixel-by-pixel basis threshold values of the NDVI for grass growth cessation was assessed. On the basis of the threshold values a colour map of the whole country was made, where different colours symbolized altogether four time intervals for suggested/simulated growth cessation of local timothy swards. Finally, minimum and maximum N uptake of timothy swards in the period close to growth cessation was calculated as a basis for the recommendation of local final dates of surface application of cattle slurry.
Forfattere
Anne Kristine Søvik Nina SyversenSammendrag
A lysimeter experiment with drained soil columns has been established in order to study the retention efficiency of particles and nutrients from artificial agricultural runoff in soil from a vegetative buffer zone. The effect of vegetation, grass versus trees and alder versus aspen, high and low runoff as well as different seasons has been examined. It was found that the retention of particles, total P and phosphate was significantly higher in the columns with trees compared to the columns with grass. In general this was the case for organic carbon and the nitrogen compounds as well. Columns with aspen and alder had equal retention efficiency for particles, organic matter and total phosphorus. Again this was in general valid for total nitrogen and nitrate as well. The retention efficiency for the measured parameters followed in general the pattern: particles/organic matter > phosphorus > nitrogen. The retention efficiency of the nutrients was generally better during the summer and early autumn compared to late autumn, for particles and organic carbon less difference between the seasons was observed.
Sammendrag
Effects of composting on survival and reproduction of the potato cyst nematode (PCN) Globodera rostochiensis were investigated in 150-liter pilot scale reactors. Small bags containing cysts of PCN were incubated in organic waste and composted for 8, 15 or 29 days. Temperatures in the areas close to the cyst bags were monitored. Survival, measured by hatching, was reduced by 99.9% already after 8 days of composting and at 29 days no hatching was recorded. A few eggs, however, still hatched after being composted for 15 days and exposed to temperatures higher than 60°C for several days. Maximal temperatures and thermal exposure time as such could not explain the hatching pattern of PCN, so other factors are likely to be involved in causing lethality. PCN failed to reproduce after 8 days of composting with temperatures reaching a minimum of 50°C during the period. Hence, eight days of composting where all material have reached a temperature of minimum 50°C during the period, could be regarded as a satisfactory method for sanitation of PCN.