In these studies, sugar maize requirements were estimated with respect to the level and method of nitrogen application and the application method of ammonium phosphate depending on the sowing date. The research was conducted near Poznań (52^o26’ N; 16^o45’ E) in years 2004-2007. It was shown that the most favourable sowing date for the yield size of cobs with covering leaves was the end of the third decade of April. Sowing delay until the third decade of May caused a significant decrease in sugar maize yield. Starter application of ammonium phosphate increased the yield of cobs with covering leaves and the number of cobs per area unit in relation to traditional spread fertilisation, although the effect of this factor depended on the weather course in the years of the research. The above fertilisation method gave positive effects particularly on the objects on which the entire nitrogen was used before maize sowing. Dose of 80 kg N·ha^-1 increased cob yield in relation to a dose smaller by a half, on condition that the entire nitrogen was used before sowing and maize was sown at the end of April. Delay in sowing time by about a month gave the opposite effect.

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