Influence of harvest season, cutting frequency and nitrogen fertilization of mountain meadows on yield, floristic composition and protein content of herbage

The aim of the present study was to investigate the influence of cutting frequency, harvest season and nitrogen fertilization on yield and floristic composition of the herbage harvested from a mountain meadow. The meadow was divided into 22 plots, each receiving a different N P K fertilization treatment. The study lasted seven years, and during the first three years (1985-1987) each plot was harvested twice per year (June and September) according to a traditional harvest system, whereas in the years 1989-1991 each plot was harvested three times per year (spring, summer and autumn) following a more intensive harvest system. Nitrogen fertilizer favoured the development of the grasses in spring, thus reducing the proportion of legumes in the two cut harvest system, whereas grasses reached an advanced stage of maturity before the first cut in late June. However, the three cut harvest system entailed an earlier first cut in spring. As a result, the production of legume biomass was significantly increased both in the first cut and in the subsequent regrowths. No significant response in total herbage production to the N fertilizer was observed in the more intensive harvest system. Therefore, the three cut harvest system without nitrogen fertilization seemed to be the most suitable practice for the management of these botanically-complex mountain meadows. These results may contribute to design fertilization and management practices of mountain hay meadows to optimize their productivity and sustainability