EN
Numerous symptoms of allelopathic activities among the plants in agrophytocenoses taken from foreign and domestic literature as well as own studies are presented. Theoretical and practical aspects of allelopathy in field plant cultivation are shown. Main sources of allelopathic compounds in agrophytocenoses such as post-harvest residues, green manures, self-sowings, weeds, mulch, and straw are suggested. The results from last 10-15 years were used to review the more important allelopathic compounds. Examples of studies indicating existence of other unidentified biologically active substances are given. The need for further investigations is indicated.