EN
This work presents the results of investigations conducted in 2005–2007 which aim was to compare the residual effect of undersown crops, straw and undersown crops with straw on the level of weed infestation in winter triticale. The following combination of organic fertilization: control object (without organic fertilization), red clover, Italian ryegrass, straw, red clover + straw, Italian ryegrass + straw. The results revealed that undersown crops plowed down as a forecrop of winter triticale and undersown crops with straw significantly reduced the biomass and number of weeds in comparison with weed infestation recoded in winter triticale cultivated in control object. The lowest weed infestation was observed in winter triticale cultivated in the second year after applying Italian ryegrass with straw.