Soil cultivation (the factor A) and nitrogen fertilization (the factor B) effects on yields of winter wheat and maize and weeds-cover was tested in the long-term experiment conducted on Keszthely Eutric cambisol (Ramann type brown forest soil) in 2005-2008 period. The bi-factorial trial was arranged in split plot design with four replications (basic plots 435 m 2 and 87 m 2, for A and B, respectively). Conventional tillage (ploughing=PL), no-till drill (NT) and disking (D) were the treatment of soil cultivation, while five rates of nitrogen (kg N ha -1: 0; 120; 180; 240; 300) were applied on blanket application of phosphorus and potassium (kg ha -1: 100 P 2O 5+100 K 2O). There was no weed control until our investigation. The weed surveys were made with Balazs-Ujvarosi coenological method. The fewer yields were obtained in the wheat-maize no-tillage system compared to the others. It was proved at high and low level alike (good and unfavourable years). In the average of years the decreasing of yield was 10-15% compared to the traditional cultivation. In survey the weed cover (%) at wheat in springtime it can be said that the weed cover increased parallel with the amount of N fertilizer and above 200 kg/ha N doses declined. The dynamic of relation of weeds v.s. N fertilizer it is similar to the square equation of yield curve. In case of maize there were not significant differences between the N treatments (25-30%) regarding the weed cover. The results draw ones attention to that facts that with the propagation of the reduced soil cultivation systems it is necessary to modify and harmonize the practice of weed control and fertilization.
