In the years 1996–1999 the effect of nitrogen fertilisation (6 rates, applied in 3 terms) and different share of spring barley and oats in mixtures on the chemical composition and the fodder value of grain were studied. The field trials were conducted at the Swadzim Experimental Station belonging to Agriculture University of Poznan. Nitrogen fertilization, effected mainly crude protein and N-free extract contents in grain. The higher nitrogen rate the higher content of
crud protein in grain was found. The share of species in sowing effected all nutrient components except crude ash. Barley, in comparison to oats, contained more crude protein and N-free extract. Mixtures were on the level between both components in pure stand. The more share of oats in mixtures, the more content of crude fat and crud ash was observed. The oats grain contained almost twice as much crude ash as barley. Nitrogen fertilization increased the amount of protein and its yield. It was found that rates of nitrogen increased the yields of metabolic energy. Oats grain was characterized by a smaller amount of energy than barley. Energetic value of mixtures was less, the more share of oats in mixtures.