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.
2020
Sammendrag
Phosphorus is an essential plant nutrient, but primary resources are limited and overfertilization may cause eutrophication of freshwater. Our objectives were to examine temperature effects on (a) optimal P rate for turfgrass establishment, and (b) increasing rates of foliar vs. granular P for early spring growth of established greens. Two trials, both on USGA root zones and replicated in April−May over 2 yr, were conducted in daylight phytotrons at 7, 12 and 17 °C. Experiment 1 compared 5 P rates from 0 to 0.48 g P m−2 wk−1 for creeping bentgrass establishment on a sand containing 13 mg P kg−1 (Mehlich‐3). Results showed no temperature effect on the optimal P rate. Bentgrass coverage and clipping yield increased up to 0.12 and 0.24 g P m−2 wk−1, corresponding to 6 and 12% of the N input, respectively. The concentration of P in clippings was higher at 7 than at 17 °C indicating that temperature was more limiting to shoot growth than to P uptake. A higher root/top ratio showed that plants invested more in roots under P deficiency. Experiment 2 was conducted using intact cores from a 4‐yr‐old creeping bentgrass (Agrostis stolonifera L.) green with a Mehlich‐3 P level of 34 mg P kg−1. Results showed increased clipping yields up to 0.18 g P m−2 wk−1 and higher P uptake with granular than with foliar application, but there was no effect on turfgrass color and no interaction with temperature. Low temperatures did not justify higher P applications.
Forfattere
Paul Eric AspholmSammendrag
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Forfattere
Joel Lönnqvist Hans Martin Hanslin Birgitte Gisvold Johannessen Tone Merete Muthanna Maria Viklander Godecke BleckenSammendrag
Standard succulent vegetation mixes developed mostly in temperate climates are being increasingly used on green roofs in different climate zones with uncertain outcome regarding vegetation survival and cover. We investigated vegetation on green roofs at nine temperate, cold, and/or wet locations in Norway and Sweden covering wide ranges of latitude, mean annual temperature, annual precipitation, frequencies of freeze-thaw cycles, and longest annual dry period. The vegetation on the roofs were surveyed in two consecutive years, and weather data were compiled from meteorological databases. At all sites we detected a significant decline in species compared to originally intended (planted/sown) species. Both the survival rate and cover of the intended vegetation were positively related to the mean annual temperature. Contrary to a hypothesis, we found that intended vegetation cover was negatively rather than positively related to mean annual precipitation. Conversely, the unintended (spontaneous) vegetation was favoured by high mean annual precipitation and low mean annual temperature, possibly by enabling it to colonize bare patches and outcompete the intended vegetation. When there is high mortality and variation in cover of the intended vegetation, predicting the strength of ecosystem services the vegetation provides on green roofs is difficult. The results highlight the needs for further investigation on species traits and the local factors driving extinction and colonizations in order to improve survivability and ensure a dense vegetation throughout the successional stages of a green roof.
Forfattere
Pia Heltoft ThomsenSammendrag
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Sammendrag
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Sammendrag
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Forfattere
Tatsiana Espevig Karin Normann Marina Usoltseva Kate Entwistle Jo Anne Crouch Trygve S. AamlidSammendrag
http://www.sterf.org/Media/Get/3321/artikel-myntflekk-in-vitro-norsk
Sammendrag
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Sammendrag
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Forfattere
Vebjørn Veiberg Erlend Birkeland Nilsen Christer Moe Rolandsen Morten Heim Roy Andersen Frode Holmstrøm Erling Meisingset Erling Johan SolbergSammendrag
Individual age is an important element in models of population demographics, but the limitations of the methods used for age determination are not always clear. We used known-age data from moose (Alces alces), red deer (Cervus elaphus), semi-domestic reindeer (Rangifer tarandus tarandus) and Svalbard reindeer (Rangifer tarandus platyrhynchus) to evaluate the accuracy and repeatability of age estimated by cementum annuli analysis of longitudinally sectioned permanent incisors. Four observers with varying experience performed blind duplicate age estimation of 37 specimens from each cervid. The relationship between known age and estimated age was linear, except for Svalbard reindeer where a quadratic model gave a slightly better fit. After correcting for observer ID and animal ID, there was a slightly declining probability to assess the correct age with increasing age for moose, red deer and Svalbard reindeer. Across cervids and observers, estimated age equalled known age in 69% of all readings, while 95% age ± 1 year. Predicted probability of correct age assessment for experienced observers was 93% for red deer, 89% for Svalbard reindeer, 84% for moose and 73% for semi-domestic reindeer. Regardless of observer experience and cervid, there was a high agreement between repeated assessments of a given animal’s tooth sections. The accuracy varied between cervids but was generally higher for observers with former ageing experience with a given cervid. We conclude that the accuracy of estimated age using longitudinally sectioned incisors is generally high, and even more so if performed by observers with former ageing experience of a given species. To ensure consistency over time, a reference material from known-age individuals for each species analysed should be available for calibration and training of observers. Age determination . Cementumannuli analysis (CAA) . Moose . Red deer . Reindeer . Incremental layer