Plant phenology, growth and nutritive quality of Briza maxima: Responses induced by enhanced ozone atmospheric levels and nitrogen enrichment

► Forage quality (foliar protein and fiber content) and phenology are more O3-sensitive than growth parameters in the Mediterranean annual grass Briza maxima. ► The effects of N supplementation depended on meteorological conditions and plant physiological activity. ► Increase in nitrogen supplementation counterbalanced the O3-induced increase in senescence biomass. ► Nutritive quality and phenology should be considered in new definitions of the O3 limits for the protection of natural herbaceous vegetation.