Agroscope, Institute for Plant Production Sciences IPS, 1260 Nyon, Switzerland

Does the grass composition of highland pastures differ from those of lowland leys?

In this paper, we compare the botanical and chemical compositions of grazed grassland located at various altitudes between 600 and 2100 m a.s.l., as part of a study on the relationships between the characteristics of grass and those of Swiss hard cheese. The lowland leys are composed only of grasses and legumes and their botanical diversity is distinctly smaller than that of the highland permanent pastures. When the altitude raises, we noticed in the latter a decrease in the proportion of grasses and an increase in numerous dicotyledonous species, especially Compositae, Rosaceae and Plantaginaceae. Some differences in the chemical composition of grass have been observed between lowland grassland and highland pastures. In the subalpine area (above 1600 m), the herbages contain much more soluble phenolic compounds and reveal a greater biological activity of the secondary metabolites. However, the digestibility of the organic matter is little influenced by the altitude.

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