Field experiments were conducted in 2005-2007 at the Brody Experimental Station (52°26’ N; 16°17’ E) of the University of Life Sciences in Poznań with the following factors: 1) cultivars with different FAO number: 210, 240 and 260; 2) fertilization with K, Mg and Na: 0 (control), 150 kg K·ha^-1, 150 kg K + 16.3 kg Mg·ha^-1, 150 kg K + 16.3 kg Mg + 13.5 kg Na·ha^-1; 3) Zn application: 0 (control), 1.5 kg Zn·ha^-1 after sowing and 1.5 kg Zn·ha^-1 at the 3-4 leaf stage. It was found that the grain yield depended more on the course of weather conditions than did plant residues yield. Maize response to potassium fertilization depended on the vegetation season. In the year favorable for the establishment of a high maize yield, simultaneous K and Mg fertilization at rates 150 and 16.3 kg·ha^-1 induced a significant grain yield increase. The influence of zinc fertilization on grain yield depended both on the vegetative period and cultivar. Early maturing cultivars responded positively to Zn and the optimal date for Zn foliar application was the 3-4 leaf stage. Maize response to sodium supplementation was not detected.

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