Assessment of the Impact of Magnesium and Nitrogen Fertilization on Two Species of Grasses Used as Horse Feed

The aim of this study was to determine the effect of nitrogen (three doses of N) and magnesium (two doses of Mg) fertilization on the yield and quality of fodder obtained from two old and extensive grass species Festulolium braunii cv. ‘Felopa’ and Lolium multiflorum cv. ‘Tur’ in field cultivation under dry conditions. F. braunii was better adapted to cultivation on light, dry soils than L. multiflorum; in such conditions, it produces higher yields of dry matter and protein, characterized by a higher concentration of nutrients. F. braunii fertilized with doses of 120 and 180 kg N∙ha−1 yielded higher than that fertilized with a dose of 60 kg N∙ha−1, and L. multiflorum produced similar yields after applying doses of 60, 120 and 180 kg N∙ha−1. For tested grass pasture, a single N application after the start of vegetation in two forms (fast- and slow-acting) appears to be adequate. Resignation from splitting the nitrogen dose due to variable rainfall distribution that can occur after the first cut during the dry summer is beneficial due to a reduction in the losses of nutrients and environmental burdens.