Polish agricultural management is dominated by the ploughing system, which is characterized by a high labor- and energy consumption. Economical and ecological aspects make farmers search for alternative tillage systems. They consist in replacing ploughing with cultivating measures which do not overturn the soil or in total omission of tillage (direct sowing). The aim of the study was determination of the effect of tillage systems and level of mineral fertilization on the grain yield as well as on chosen structural components of the yield and winter wheat stand. Field experiments were carried out in the years 2003-2006 on lessive soil formed from loess. The experiment included various tillage systems: A – conventional tillage (control): skimming 8-10 cm + double harrowing, presow ploughing (18-20 cm) + harrowing; B – reduced tillage: single pre-sow ploughing (to 15 cm) + harrowing; C – reduced tillage: disking + harrowing, cultivating + harrowing. The second experimental factor were levels of mineral fertilization: a – 135.5 kg NPK per 1ha (N – 60; P – 17.4; K – 58.1), b – 203.4 kg NPK per 1 ha (N – 90; P – 26.2; K – 87.2). Winter wheat was cultivated in a four-field crop rotation: potato – spring wheat – field peawinter wheat. Research presented in this paper concerns the second cycle of crop rotation. Reduced tillage significantly decreased the grain yield in winter wheat, compared to the conventional ploughing system. Replacing ploughing with cultivating and harrowing affected a significant decrease in the plant height and spike density per 1 m² of winter wheat. Higher level of mineral fertilization increased the grain yield on average by 0.3 Mg·ha^-1. The study did not indicate any significant effect of tillage system and levels of mineral fertilization. In the second cycle of crop rotation, an increase in the grain yield was observed on all experimental plots, as well as in most structural components of the stand and winter wheat yield, compared to the one obtained in the first rotation.

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