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.
2011
Forfattere
Anne Linn Hykkerud Steindal Jørgen Mølmann Tor J. Johansen Gunnar BengtssonSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor J. JohansenSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor J. JohansenSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor J. JohansenSammendrag
Production of healthy, vigorous potato plants and a high yield of good quality under varied environmental conditions require quality seed tubers. Quality may be divided in two important factors, tuber health and physiological quality. Physiological quality (number and vigour of sprouts and stems, growth and yield potential) is determined by the size of the seed tuber, the physiological status of the seed and interactions between these two factors. The physiological status of the seed is usually called physiological age. This may be defined as “the stage of development of a tuber, which is modified progressively by increasing chronological age, depending of growth history and storage conditions” (Struik and Wiersema 1999, Seed potato technology). The sequence of stages of development are dormancy, apical sprouting, normal sprouting with a few or multiple branched sprouts, senility and finally incubation with direct formation of daughter tubers on the seed tuber. Each stage has a strong influence on vigour and yield potential of the seed. Temperature is the most important environmental factor that affects physiological age in seed potatoes, either during growth of the mother plant, or during storage. Unfortunately, physiological age is hard to measure directly, and indirect methods, based on sprout development, sprout characteristics and sprouting capacity are normally used. In Norway, several studies of the impact of geographic origin, growth temperatures, day-lengths, and pre-storing temperatures on vigour and yield potential have been performed the last10 years. One of the aims has been to study the “northern vigour claims”, which implies superiority of seed produced in northern latitudes over seed produced in southern latitudes. In summary the results showed: Low temperature (9 ºC) gave a small but positive effect on progeny growth vigour and yields compared to a higher temperature (15 ºC) in cv. ‘Troll’. Day-length (12 or 24 hrs) did not affect the results significantly. In a study with average temperatures of 9, 15 and 18 ºC, 12 and 24 hrs day-lengths, the physiologically oldest tubers originated from the lowest growth temperatures. In a three-year field study at distant sites in Norway (lat. 59-70) the results showed no superiority of seed from any latitude, regarding vigour and yields. In a controlled climate study at 9, 15 and 21 °C, results showed that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures (4 °C). The scientific fundament of “northern vigour” is still not clear, but as a statement it may call attention to the generally good quality of northern seed.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Tor J. JohansenSammendrag
Dormancy in a potato tuber prevents sprout growth even under optimal sprouting conditions and is the first stage in the physiological ageing process. The intensity and duration of this phase differs between genotypes (cultivars) and may also be affected by environmental conditions both during tuber bulking and early storage. The current study aimed at finding how simulated high latitude growth conditions influence dormancy and the physiological age of tubers to be used as seed potatoes. In a controlled climate at natural light conditions, tubers grown at a low temperature (9°C) had 2-3 weeks shorter dormancy than tubers grown at higher temperatures (15 and 21°C). In tubers grown at artificial light conditions, day-lengths (12, 18 or 24 h) did not affect dormancy significantly. A post-harvest treatment with a low temperature (one month at 4°C and subsequently 18°C) reduced dormancy by 2-3 weeks in tubers from the highest growth temperatures (15 and 21°C) in comparison with constant 18°C post-harvest. After the lowest growth temperature (9°C) the duration of dormancy was not affected by post-harvest temperature treatments. Physiological age was determined by sprouting characteristics after winter storage. At this stage the sprouting capacity was highest in tubers originating from the lowest and the highest growth temperatures. Further, the number of sprouts per tuber was higher in tubers grown at 9°C than at 15 or 21°C. These results were not correlated with duration of dormancy after the various treatments, suggesting that temperatures may affect dormancy and physiological ageing independently. The present results show that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures at higher growth temperatures.
Sammendrag
The main goal of this study was to develop an alternative bedding material for cattle and sheep based on locally produced woodchips from birch trees and Sphagnum peat in Northern Norway. Four litter mixtures; 2.5 and 5.0 cm woodchips, with and without 20 % peat of total volume were studied in A) Four pens sized 20.4 m2 with two cattle each, ie one pen per treatment; B) Eight pens sized 21.2 m2 with seven ewes each, ie two pens per treatment, and two similar sheep pens with deep straw (barley) as controls. The number of lying animals was counted in 10 minutes’ intervals from 6 pm to 6 am for two consecutive days and the mean number of animals lying simultaneously per pen and hour, was calculated. The cleanliness of the animals was assessed within three separate body sections (legs, side, rear) using a scale from 0-2 points for each body part (0 p=clean, 6 p=dirty). The proportion of animals lying simultaneously per pen and hour and individual cleanliness scores were analysed by GLM. No differences in lying behaviour and cleanliness between the four woodchips mixtures were found, neither for sheep nor cattle. However, straw bedding resulted in the least dirty ewes (P
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Bente Kirkhus Britt I.F. Henriksen Aina Lundon G.I. Borge J-E Haugen G. VogtSammendrag
Camelina is an underexploited oilseed crop that may be well suitable for cropping innorthern areas. The oil is particularly high in the omega-3 fatty acid alpha-linolenic acid (C18:3n-3). The aim of the present study was to evaluate the potential for secure production of high quality edible oil from organically grown camelina (Camelina sativa L. Crantz), focusing on the effects ofenvironmental parameters on oil content, fatty acid composition and contents of phytosterols and tocopherols. Field experiments with pre-crop barley were conducted in the growing seasons 2007, 2008 and 2009. Trials were fully randomized with two levels of Nitrogen (N) fertilization, 0 and 120 kg total Nha-1, and two levels of Sulphur (S) fertilization, 0 and 20 kg total S ha-1. Additional experiments were performed in 2009 in order to evaluate the effects of replacing pre-crop barley with pre-crop pea. Crude oils were obtained by usinga pilot press and the fatty acid composition and contents of phytosterols and tocopherols were analyzed by GC-MS and LC-MS. The results showed significantseasonal variations in the contents of fatty acids, tocopherols andphytosterols. Furthermore, significant effects of N-fertilization were observed, with increased contents of C18:3n-3, erucic acid (C22:1) and γ-tocopherol at the highest level of N-fertilization. Pea compared to barley as pre-crop also increased the content of C18:3n-3. There were no effects of S-fertilization. Principal component analysis revealed positive correlations between the contents of C18:3, C22:1, γ-tocopherol and phytosterols, in particular brassicasterol. In conclusion, camelina seems to be well suitable for organic cropping. The oil quality was influenced by season and N-fertilization, still, the variation in nutrient content was small.
Forfattere
Ingvar Kvande Reidun PommerescheSammendrag
Små opplegg knyttet til forskning rettet mot elever i 10 klasser. Vi forklarte og viste hvordan husdyrgjøsel kan brukes til å lage gass, at det er bakterier som er viktige. vi såg også på ulike rotknoller på belgvekster hvor det lever tusenvis av bakterier som kan gjøre nitrogengass i lufta om til nitrogenholdige stoffer som planten kan bruke. Biologi trengs for at det skal skje kjemi.