EN
The objective of the studies was to assess a residual effect of varying organic fertilizers (manure and stubble crop with ploughing down by-products every year) and varying nitrogen doses (0, 45, 90, 135, 180 kg N/ha) on weed infestation of winter barley. Using organic fertilizers in fore-forecrop slightly decreased dry matter of weeds in comparision with dry biomass of weeds on plots without organic fertilization. Intensification of nitrogen fertilization generally reduced dry matter of weeds in winter barley. Manure and stubble crop with by-products as well as intensification of nitrogen fertilization slightly decreased the number of weeds in barley stand from tillering to maturing of winter barley.