Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2018
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Academic – Robotic in-row weed control in vegetables
Trygve Utstumo, Frode Urdal, Anders Brevik, ...
Authors
Trygve Utstumo Frode Urdal Anders Brevik Jarle Dørum Jan Netland Øyvind Overskeid Therese With Berge Jan Tommy GravdahlAbstract
Vegetables and other row-crops represent a large share of the agricultural production. There is a large variation in crop species, and a limited availability in specialized herbicides. The robot presented here utilizes systematic growing techniques to navigate and operate in the field. By the use of machine vision it separates seeded vegetable crops from weed. Each weed within the row is treated with individual herbicide droplets, without affecting the crop. This results in a significant reduction in herbicide use, and allows for the use of herbicides that would otherwise harm the crop. The robot is tailored to this purpose with cost, maintainability, efficient operation and robustness in mind. The three-wheeled design is unconventional, and the design maintains maneuverability and stability with the benefit of reduced weight, complexity and cost. Indoor pot trials with four weed species demonstrated that the Drop-on-Demand system (DoD) could control the weeds with as little as 7.6 μg glyphosate or 0.15 μg iodosulfuron per plant. The results also highlight the importance of liquid characteristics for droplet stability and leaf retention properties. The common herbicide glyphosate had no effect unless mixed with suitable additives. A field trial with the robot was performed in a carrot field, and all the weeds were effectively controlled with the DoD system applying 5.3 μg of glyphosate per droplet. The robot and DoD system represent a paradigm shift to the environmental impact and health risks of weed control, while providing a valuable tool to the producers.
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The potential impact of silver nanoparticles (Ag NPs) on aquatic organisms is to a large extent determined by theirbioavailability through different routes of exposure. In the present study juvenile Atlantic salmon (Salmo salar) were exposed todifferent sources of radiolabeled Ag (radiolabeled110mAg NPs and110mAgNO3). After 48 h of waterborne exposure to 3mg/Lcitrate stabilized110mAg NPs or110mAgNO3, or a dietary exposure to 0.6mg Ag/kg fish (given as citrate stabilized or uncoated110mAg NPs, or110mAgNO3), Ag had been taken up in fish regardless of route of exposure or source of Ag (Ag NPs or AgNO3).Waterborne exposure led to high Ag concentrations on the gills, and dietary exposure led to high concentrations in thegastrointestinal tract. Silver distribution to the target organs was similar for both dietary and waterborne exposure, with the liveras the main target organ. The accumulation level of Ag was 2 to 3 times higher for AgNO3than for Ag NPs when exposure wasthrough water, whereas no significant differences were seen after dietary exposure. The transfer (Bq/g liver/g food or water)from exposure through water was 4 orders of magnitude higher than from feed using the smallest, citrate-stabilized Ag NPs(4 nm). The smallest NPs had a 5 times higher bioavailability in food compared with the larger and uncoated Ag NPs (20 nm).Despite the relatively low transfer of Ag from diet to fish, the short lifetime of Ag NPs in water and their transfer to sediment,feed, or sediment-dwelling food sources such as larvae and worms could make diet a significant long-term exposure route.
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Runoff prediction in ungauged catchments has been a challenging topic over recent decades. Much research have been conducted including the intensive studies of the PUB (Prediction in Ungauged Basins) Decade of the International Association for Hydrological Science. Great progress has been made in the field of regionalization study of hydrological models; however, there is no clear conclusion yet about the applicability of various methods in different regions and for different models. This study made a comprehensive assessment of the strengths and limitations of existing regionalization methods in predicting ungauged stream flows in the high latitudes, large climate and geographically diverse, seasonally snow-covered mountainous catchments of Norway. The regionalization methods were evaluated using the water balance model – WASMOD (Water And Snow balance MODeling system) on 118 independent catchments in Norway, and the results show that: (1) distance-based similarity approaches (spatial proximity, physical similarity) performed better than regression-based approaches; (2) one of the combination approaches (combining spatial proximity and physical similarity methods) could slightly improve the simulation; and (3) classifying the catchments into homogeneous groups did not improve the simulations in ungauged catchments in our study region. This study contributes to the theoretical understanding and development of regionalization methods.
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Authors
Trygve S. Aamlid Gudni Thorvaldsson Anne Mette Dahl Jensen Pia Heltoft Tatsiana Espevig Trond Olav Pettersen Jan TangsveenAbstract
No abstract has been registered
Authors
Anne Linn Hykkerud Eivind Uleberg Espen Hansen Marieke Vervoort Jørgen A.B. Mølmann Inger MartinussenAbstract
Cloudberry (Rubus chamaemorus L.) is a wild perennial shrub growing on peatland with a circumpolar distribution. The combined berries have a high polyphenol content comprised primarily of ellagitannins. A few commercial cultivars are available, and pre-breeding trials on clonal material from different geographical origins are in progress. The objective of this study was to investigate how the content of polyphenols of four different cloudberry cultivars were affected by harvesting time and climatic variations during a 3-year-period. Plants were grown outside in plots and berries were harvested when mature. Berries were analyzed for total polyphenols and total anthocyanins by spectrophotometer. Total ellagic acid was identified and quantified using HPLC-MS after hydrolysis of the extracts. Results showed that all measured parameters; total anthocyanins, total polyphenols and ellagic acid are strongly influenced by the genetic background. Although low anthocyanin contents were present in all genotypes, they were highly affected by climatic conditions, being highest at low temperatures. However, the content of ellagic acid was less affected by environmental conditions and showed little response to changing temperatures. In conclusion, ellagitannin content was the most dominating polyphenol group observed in this study and was affected by genetics and is therefore a good breeding criterion for increased health benefit of cloudberry.