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Browsing by Author "Korhonen, Panu"

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  • Korhonen, Panu (2014)
    Finland is the northernmost cultivation area in the world and the selection of forage grass species is mostly limited by long winters and short growing seasons. Forage grasses are usually grown as mixtures of species and produced intensively for silage. The grass species most commonly used in mixtures are timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis L.) which are both winter hardy species. As the climate changes in the future, more southern and more productive species like perennial ryegrass (Lolium perenne L.) and festulolium (Festuca sp. x Lolium sp.) may become more usable. The duration of snow cover has been predicted to shorten to 46 days in southern Finland by year 2050 (compared with 98 days at present). The autumns, when plants develop their tolerance against winter stresses, are also predicted to become warmer in the future. Changes in winter weather may also increase the frequency of problems such as plant exposure to freezing temperatures, associated with decreased snow cover and ice encasement due to fluctuating winter temperatures. This study presents the results of experiments carried out in Helsinki (Finland) between years 2009–2013. The experiments were done to assess the freezing tolerances and vernalisation of forage grasses and cereals hardened under field conditions. The vernalisation of plants was detected in all species as a decrease in days to heading during the vernalisation period. Perennial ryegrass and meadow fescue started flowering after the vernalisation was fulfilled during December-January. Winter cereals had already vernalised already in November. Hardening periods started at their earliest in the beginning of October. However, a deeper freezing tolerance developed during December in 2009–2010 and 2011–2012. During the winters of 2009–2010 and 2011–2012 hardening periods were long and hardening-induced temperature sums were the highest. During these winters the freezing tolerances were better in all species than during the other two winters.