The aim of this study was to evaluate weed infestation (the number, biomass and species composition) of husked and naked oats canopy depending on the soil tillage system (conventional, simplified with a catch crop, simplified, direct sowing) and the method of plant cultivation (mechanical and chemical) The study was carried out in 2000-2002, in Alfisols, formed from loess. The subject of the investigation was husked oats (cultivar Borowiak) and naked oats (cultivar Akt III). The largest number of weeds occurred in the canopy of husked (123 pcs·m^-2) and naked (102 pcs·m^-2) oats cultivar after the use of direct sowing, and in the cultivar Akt III also after simplified tillage (68.7 pcs·m^-2). The largest dry matter of weeds was determined after the application of direct sowing (Borowiak – 104.8; Akt III – 100.5 g·m^-2) and simplified tillage (Borowiak – 72.5; Akt III – 64.1 g·m^-2). The smallest number and weight of weeds in canopies of both oats cultivars was found after conventional soil cultivation and after simplified tillage with the use of catch crop. Introducing chemical weed control affected a reduction in number and dry matter of weeds in the range from 16 to 22%, both in the canopy of cultivar Borowiak and Akt III. This was particularly effective in treatments where direct sowing and simplified tillage was used. Among weeds short-lived species predominated, but more of them occurred in the canopy of cultivar Akt III than in the canopy of the cultivar Borowiak. Tillage system and the method for weed control had a similar effect on the weed control in canopies of naked and husked oats cultivars.

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