The aim of the study was to assess the effect of water extracts from crop residues and self-seedings of winter rape and soil extracts after its harvesting on the germination energy and capacity, as well as initial growth of winter rape under laboratory conditions. In first part of research the influence of different extracts (from: a – stems, b – siliques and c – young plants of winter rape) at three concentrations: (0.25; 0.5 and 1%) was examined. Control (0%) was watered with distilled water. In second part of research the effect of soil extracts from fields under crop with different proportions of winter rape in crop rotation (0, 33, 66 and 100%) was examined. The seeds watered with self seeding winter rape extracts in comparison with siliques and stems extracts were characterized by a significantly worse germination energy and capacity. In addition the seedlings had the significantly smaller height and the shorter seedling roots. Independently of the kind of extract, significantly worse results of seed germination and initial growth of winter rape seedlings were observed along with an increase in winter rape extract concentrations. It was found that the soil extracts after 3-year winter rape monoculture significantly reduced germination energy and length of seedling roots and also caused tendencies for smaller germination capacity and seedling height in comparison with those watered with extract from soil where rape was not grown for last 3 years and with distilled water.

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