Introduction

Introduction Climatic conditions, characterized by moderate to low summer temperature and very variable winter conditions, limit the potential of crop production in the West Nordic countries. Under these climatic conditions, husbandry based on grass and clover forage is of greatest importance. As the plants have to survive harsh winter conditions the grass and clover species used must have great tolerance to frost, ice cover and temperature fluctuation (Gudleifsson et al. 1986; Bélanger et al. 2006; Höglind et al. 2010) as well as diseases (Larsen 1994). Furthermore, the grasses have to tolerate intensive grassland management (Hermannsson & Helgadóttir 1991). It is therefore important to consider both climate and management when evaluating forage species and varieties for use in these countries. There is a general consensus among scientists that the temperature on earth is increasing because of the green house effects (IPPC 2013). Small temperature changes can strongly affect agricultural production and may affect the choice of species and varieties. If climate conditions within the West Nordic area change as a result of global warming it is important to have information about which species and varieties can grow well under varied climatic conditions and which have limitations. The main goal of this project was to evaluate important forage species and varieties used in the West Nordic countries for future use and to find which varieties have a wide adaptation and can be used in a wide range of climatic conditions. Furthermore, we wanted to elucidate which are limited to specific conditions. For testing persistence and agronomic values of selected varieties (cultivars) of forage species, a series of uniform experiments under a range of different climatic conditions was performed. Twenty four varieties of grass and clover species were sown at seven locations in the West Nordic countries and at one location in Sweden in 2009 and 2010. In addition one treatment with a mixture of four species was included.

Fig. 1. Harvest at Korpa 2011 (GÞ).