Abstract
Because of recurrent drought events in the last een years, grassland irrigation has gained relevance in the mountainous areas of the southern slopes of the Alps. Besides the beneecial eeects on forage yield, the eeect of the irrigation on the botanical composition of grassland represents a relevant issue for grassland management, but experimental evidence about this topic is limited. A data set describing the botanical composition of permanent meadows at the rst cut at 220 environments in South Tyrol (NE Italy), encompassing a broad range of environmental conditions and management intensities, was used to explore the eeect of irrigation on the most common grassland species by means of mixed models taking into account the design eeects, N input and the occurrence of irrigation. For about one-third of the species a signiicant (Dactylis glomerata, Lolium perenne) or marginally signiicant (Poa trivialis, Rumex acetosa) eeect of irrigation on their yield proportion could be ascertained. Speciically designed research is required to provide more precise information about this topic.