EN
A field experiment was carried out in Koniczynka near Toruń in 2000–2008. During eight years of investigation a weed population was observed and analyzed in three tillage systems of sugar beet crop mustard mulch, rye mulch, phacelie mulch and plough mustard. The weed number in white mustard, winter rye, and tensy phacelia mulches decreased in comparison to mustard crop ploughed in the autumn. The highest reduction of weed infestation were found on winter rye mulch (16.1%) in comparison to plough mustard. Differences in weed infestation intensity of Chenopodium album, Amaranthus retroflexus, Matricaria inodora, Stellaria media, Polygonum convolvulus and Veronica agrestis population in crop rotation depended on allelopathic properties of investigated mulch.