Over 1984-1994 field experiments which aimed at defining the effect of nitrogen fertilisation on the yield of grain and protein in winter barley were carried out at the Research Station of the University of Technology and Agriculture in Bydgoszcz, located at Mochełek in the vicinity of Bydgoszcz. The experiment factor consisted of 4 levels of nitrogen fertilisation: 0, 60, 120 and 180 kg N.ha^-1. Increasing nitrogen fertilisation resulted in, for an average of 10 years, significant increases in grain and total protein yields as well as in the total nitrogen content in grain up to 120 kg N.ha^-1. The application of 180 kg N.ha^-1 decreased the grain yield, caused a breakdown in an increase dynamics for total protein yield and substantially increased the total nitrogen content in grain. The results obtained show that weather conditions in subsequent research years modified considerably the effect of nitrogen fertilisation on the winter barley characteristics studied.

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