The aim of the paper was to evaluate the efficiency of nitrogen from ammonium saltpeter as related to the formulation of phosphorus fertilizer under maize grain cropping. Maize was grown in monoculture throughout the consecutive years 2003- -2007. A two factorial field experiment was established at a farm located in Nowa Wieś Królewska (52^o26’ N; 17^o57’ E) on a slightly acidic soil, moderately rich in phosphorus. Experimental factors were as follows: (i) chemical formulation of the fertilizer, (partially acidulated phosphate rock – PAPR, simple superphosphate – SSP and triple superphosphate – TSP), (ii) nitrogen rate: 80 and 140 kg N·ha^-1; a phosphorus unfertilized treatment was also considered. The type of phosphorus fertilizer did not differentiate nitrogen uptake, but the lack of phosphorus at the applied rate has induced a decrease in nitrogen accumulation in the aboveground biomass, on average by 8%. Phosphorus fertilization at the rate 26.4 kg P·ha^-1 was the main determinant of nitrogen uptake by the kernels. Nitrogen recovery (R) from the fertilizers as well as its agronomical (AE) and physiological (PE) efficiency were significantly lower in treatments where phosphorus was not applied. Furthermore, it was found a positive effect of sulphur from simple superphosphate on the AE after the application of 80 kg N·ha^-1. The R values did not depend on the chemical formulation of phosphorus in the fertilizer and amounted on average to 74 and 59% for the rates 80 and 140 kg N·ha^-1, respectively, whereas for the treatment without P, these values varied within the range 46-54%.

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