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.
2017
Authors
Wendy Marie WaalenAbstract
No abstract has been registered
Abstract
Different sowing methods and sowing rates were evaluated in organic seed production of timothy (two trials), meadow fescue (two trials) and red clover (one trial) in Southeast Norway, during 2010–2013. The plan included: (1) broadcast sowing of grass/clover, cover crop sown at 12 cm row distance; (2) sowing of cover and seed crop in crossed rows, both at 12 cm row distance; and (3) sowing of cover crop and seed crop in every other row. The three sowing rates were 5, 10 and 15 kg ha−1 in timothy and meadow fescue and 3, 6 and 9 kg ha−1 in red clover. On average for sowing rates and all trials with timothy, meadow fescue and red clover, first year’s seed yields were 5–6%, 20–25% and 19–25% higher on plots sown with cover crop and seed crop in every other row than on plots where seed crop had been broadcast or sown perpendicularly to the cover crop. The different sowing methods had no effect on weed coverage or weed contamination in the cleaned seed. Increasing sowing rate usually had a negative influence on seed yield, while weed coverage/contamination was not significantly affected. It is concluded that organic seed crops should be established with cover crop and seed crop in every other row at a low sowing rate. However, in an organic production system, even this favorable method will not always be sufficient to meet the requirement for seed crop purity.
Authors
Lars T. HavstadAbstract
No abstract has been registered
Authors
Unni AbrahamsenAbstract
No abstract has been registered
Abstract
Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this model, four winter wheat cultivars were sown in a field experiment in Uppsala, Sweden in 2013 and 2014. The LT50 was determined by tests of frost tolerance in November, and the cultivars’ LT50c was estimated. Further, recorded winter survival from 20 winter wheat field variety trials in Sweden and Norway was collected from two winter seasons with substantial winter damages. FROSTOL simulations were run for selected cultivars at each location. According to percentage of winter damage, the cultivar survival was classified as “survived,” “intermediate” or “killed.” Mean correspondence between recorded and simulated class of winter survival was 75% and 37% for the locations in Sweden and Norway, respectively. Stress factors that were not accounted for in FROSTOL might explain the poorer accuracy at the Norwegian locations. The accuracy was poorest for cultivars with intermediate LT50c levels. When low temperature was the main cause of damage, as at the Swedish locations, the model accuracy was satisfying.
Abstract
Ice encasement (IE) is the most economically important winter stress in Scandinavia; however, little is known about the IE tolerance of different turfgrass species and subspecies except that creeping bentgrass (Agrostis stolonifera L.) is more tolerant than annual bluegrass (Poa annua L.). The objective of this study was to assess the impact of IE and two protective covers (plastic and plastic over a 10-mm woven mat) on the winter survival of six cool-season turfgrasses commonly used on golf greens. The experiment was conducted on a sand-based green at Apelsvoll, Norway (60°42′ N, 10°51′ E) during the winters of 2011–2012 and 2012–2013. Turfgrass samples (8 cm in diameter, 10 cm deep) were removed from the plots at the time of cover installation and throughout the winter. The samples were potted and percent live turfgrass cover assessed after 21 d of regrowth in a growth chamber. Percent turfgrass cover, percent disease, and turfgrass quality were also registered in the field plots in spring. Results indicated that velvet bentgrass (Agrostis canina L.) had superior tolerance to IE, surviving for 98 and 119 d of IE during the winters of 2011–2012 and 2012–2013, respectively. The order of IE tolerance in 2012–2013 was: velvet bentgrass > creeping bentgrass > Chewing’s fescue (Festuca. rubra L. ssp. commutata), slender creeping red fescue (F. rubra L. ssp. litoralis) ≥ colonial bentgrass (A. capillaris) > annual bluegrass. Colonial bentgrass responded negatively to both protective covers in 2012 due to the development of Microdocium nivale. None of the species benefited from the plastic cover alone, compared with natural snow conditions. Annual bluegrass was the only species that benefited from plastic over a woven mat.
Abstract
Ice encasement (IE) is the most economically important winter stress in Scandinavia; however, little is known about the IE tolerance of different turfgrass species and subspecies except that creeping bentgrass (Agrostis stolonifera L.) is more tolerant than annual bluegrass (Poa annua L.). The objective of this study was to assess the impact of IE and two protective covers (plastic and plastic over a 10-mm woven mat) on the winter survival of six cool-season turfgrasses commonly used on golf greens. The experiment was conducted on a sand-based green at Apelsvoll, Norway (60°42′ N, 10°51′ E) during the winters of 2011–2012 and 2012–2013. Turfgrass samples (8 cm in diameter, 10 cm deep) were removed from the plots at the time of cover installation and throughout the winter. The samples were potted and percent live turfgrass cover assessed after 21 d of regrowth in a growth chamber. Percent turfgrass cover, percent disease, and turfgrass quality were also registered in the field plots in spring. Results indicated that velvet bentgrass (Agrostis canina L.) had superior tolerance to IE, surviving for 98 and 119 d of IE during the winters of 2011–2012 and 2012–2013, respectively. The order of IE tolerance in 2012–2013 was: velvet bentgrass > creeping bentgrass > Chewing’s fescue (Festuca. rubra L. ssp. commutata), slender creeping red fescue (F. rubra L. ssp. litoralis) ≥ colonial bentgrass (A. capillaris) > annual bluegrass. Colonial bentgrass responded negatively to both protective covers in 2012 due to the development of Microdocium nivale. None of the species benefited from the plastic cover alone, compared with natural snow conditions. Annual bluegrass was the only species that benefited from plastic over a woven mat.
Abstract
No abstract has been registered
Abstract
There has long been a claim that winter injuries of grass are a significant economic burden for golf courses in the Nordic countries. To confirm this claim, in 2015 the Norwegian Institute of Bioeconomy Research and the Norwegian Golf Federation, with support of the Scandinavian Turfgrass and Environment Research Foundation, conducted a net-based survey about winter injury in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden). This comprehensive survey showed that total costs of repair of winter-injured greens and fairways together with lost revenue on golf courses in the Nordic countries can be at least €14 million. In a year with significant winter injuries, the average cost to repair the turf was between €3000 and €12,000 on 88% of the courses. The revenue loss after a winter with considerable injuries was less than €6000 at 50% of the courses, and 25% of the courses reported a loss between €6000 and €12,000 for these years. The causes of winter injuries varied depending on geography and grass species used on the greens. Biotic factors played a major role in the southern part of Scandinavia, and ice and water injuries were most devastating north of 60°N. This paper summarizes some of the answers from the respondents, including information about the dominating grass species on Nordic golf greens.
Abstract
During August 2013, white-grayish lesions, typical of Sclerotinia stem rot, had developed around leaf axils on the stems of turnip rape ‘Pepita’ in a field at the NIBIO research station Apelsvoll in Oppland County, Norway. Sclerotia were collected from inside infected turnip rape stubble and from harvested seeds, surface sterilized, bisected, and placed onto potato dextrose agar (PDA). Following 1 to 2 days incubation at 20°C, fast-growing white mycelium characteristic of Sclerotinia was observed, and within 5 to 7 days, new sclerotia had started to develop. Sclerotia size and growing pattern although variable was characteristic of S. sclerotiorum. DNA extraction, PCR amplification, and sequencing of the ITS regions of the rDNA was then carried out for 20 isolates. BLASTn analysis of 475 bp amplicons showed that 15 isolates were S. sclerotiorum, while five were identified as S. subarctica (previously called Sclerotinia sp 1; Holst-Jensen et al. 1998; Winton et al. 2006, 2007), with 100% identity to a U.K. S. subarctica isolate (Clarkson et al. 2010). A representative ITS region sequence was deposited in GenBank (accession no. KX929095). The identity of the S. subarctica isolates was further confirmed by the lack of a 304-bp intron in the LSU rDNA compared with S. sclerotiorum (Holst-Jensen et al. 1998), which was visualized by PCR amplification and gel electrophoresis. Sclerotia of two S. subarctica isolates were placed on PDA and incubated for 7 days. Agar plugs of actively growing mycelium were used for the pathogenicity testing of spring oilseed rape plants (‘Mosaik’) in the greenhouse. Plants were inoculated at growth stage BBCH 57/59 (preflowering) and BBCH 64 (40% of flowers open) by attaching two PDA plugs of actively growing mycelium per main stems with small needles, using four plants per treatment. Noninoculated PDA agar plugs were attached to the control plants. The experiment was repeated three times. Symptoms typical of stem rot appeared after 1 to 2 weeks of incubation at 16 to 20°C, 100% relative humidity. Stems started to develop white lesions with fluffy mycelium around the inoculation sites. Control plants did not show the characteristic symptoms for Sclerotinia infection. After senescence of the plants, sclerotia were collected from inside the stems and cultured on PDA. White mycelium started to grow after 1 to 2 days and new sclerotia were formed within 7 days, similar to the ones used for producing the initial isolate. Brassica oil seed crops are cultivated as important break crops in the cereal-based production system in Norway and can be severely affected by Sclerotinia stem rot. The disease is observed in all regions where Brassica oil seed crops are grown, and in severe cases, a reduction in oilseed yield of 25% has been recorded in untreated control treatments of fungicide trials. Although S. subarctica has been previously reported on wild hosts (Holst-Jensen et al. 1998), this is the first report of the pathogen on a crop plant in Norway. In the United Kingdom, Clarkson et al. (2010) demonstrated pathogenicity of S. subarctica isolated from Ranunculus acris on oilseed rape. As symptoms for S. subarctica and S. sclerotiorum are indistinguishable, S. subarctica might be present undetected in many farmer fields.