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
Authors
Björn Ringselle Erik Bertholtz Ewa Magnuski Lars Olav Brandsæter Kjell Mangerud Göran BergkvistAbstract
Tillage controls perennial weeds, such as Elymus repens, partly because it fragments their underground storage organs. However, tillage is difficult to combine with a growing crop, which limits its application. The aim of this study was to evaluate how soil vertical cutting with minimum soil disturbance and mowing affect the growth and competitive ability of E. repens in a grass–clover crop. A tractor-drawn prototype with vertical disks was used to fragment E. repens rhizomes with minimal soil and crop disturbance. In experiments performed in 2014 and 2015 at a field site close to Uppsala, Sweden, the rhizomes were fragmented before crop sowing (ERF), during crop growth (LRF), or both (ERFCLRF). Fragmentation was combined with repeated mowing (yes/no) and four companion crop treatments (none, Italian ryegrass, white clover, and grass/clover mixture). The results showed that in the grass–clover crop, rhizome fragmentation reduced E. repens rhizome biomass production and increased Italian ryegrass shoot biomass. ERF and LRF both reduced E. repens rhizome biomass by about 38% compared with the control, while ERFCLRF reduced it by 63%. Italian ryegrass shoot biomass was increased by 78% by ERF, 170% by LRF and 200% by ERFCLRF. Repeated mowing throughout the experiment reduced E. repens rhizome biomass by about 75%. Combining repeated mowing with rhizome fragmentation did not significantly increase the control effect compared to mowing alone. We concluded that rhizome fragmentation using vertical disks can be used both before sowing and during crop growth to enhance the controlling effect of grass–clover crops on E. repens.
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No abstract has been registered
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Rhodiola rosea is a well-known herbal medicinal plant, valued for highly active secondary metabolites. It is growing wild in most parts of Norway and mountainous areas in a number of countries. Some of the most important metabolites are believed to be salidroside, cinnamyl alcohol, glycosides (rosine, rosavine, rosarine), flavonoids (rhodionin, rhodiosin,rhodiolin) and terpenes (Galambosi 1999). In Norway, germplasm collections of R. rosea are maintained by NIBIO; at Apelsvoll in southern Norway, consisting of 97 different clones. The ranges in content of secondary metabolites in the collection are for rosavin 2.90-85.95 mg g-1, salidroside 0.03-12.85 mg g-1, rosin 0.08-4.75 mg g-1, tyrosol 0.04-2.15 mg g-1 and cinnamyl alcohol 0.02-1.18 mg g-1. Clones selected from the collection has throughout been studied for different aspects affecting plant growth and production of secondary metabolites. We have looked into cultivation requirements of the plant like water requirement, effects of nutrient levels (N and K) and soil types. Postharvest treatment from washing, cutting,drying and differences in the plant parts. Finally we will in this presentation also present results on requirements for dormancy release and the clonal differences and also how use of primers may affect production of secondary metabolites.
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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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No abstract has been registered
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No abstract has been registered
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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.