A two-factorial field experiment was set up with the split-block method in four replications. Potato was planted in a four-field rotation: potato – spring wheat – seed pea – winter wheat. The influence of three methods of soil tillage and two levels of mineral fertilization of potato canopy were studied. Methods of tillage: A – skimming (10-12 cm) + harrowing (2 times) + manure + fall ploughing (25-30 cm), B – cultivating (10-12 cm) + manure + fall ploughing (25-30 cm), C – disking (10-12 cm) + manure + fall ploughing (25-30 cm). Fertilization levels: a – 144.3 kg NPK ha-1, b – 216.5 kg NPK ha-1. Yield of particular fractions of tubers was estimated on the basis of 10 potato plants per plot. Potato tubers were divided into 5 fractions: below 3 cm, from 3 to 4 cm, 4 to 5 cm, 5 to 6 cm, and above 6 cm in diameter. In the individual fraction the number and weight of potato tubers as well as percentage share in a sample were determined. Determination of starch content was done by means of Reimann weight. The obtained results were statistically analysed by means of variance analysis, and the mean values were estimated by Tukey test (p = 0.05). The reduced tillage in post harvest cultivation had no significant influence on the total and commercial tuber yield nor on the percentage content and yield of starch. However, the total tuber yield was modified by the level of fertilization. Significantly higher tuber yield (by 6.5%), commercial yield (by 6.0%) and starch yield (by 7.8%) were due to intensive fertilization (b).