The interception of atmospheric precipitation in plants is the first hydrological process which differentiates precipitation at the ground surface. That is why the problem of measuring the interception of precipitation has attracted the attention of many scientists. This paper includes a characterization of the measuring instruments and the methods of investigation used in previous studies. It also shows the authors’ conception of measuring this phenomenon with the help of a gutter rain gauge. Interception passed with this instrument proved its satisfactory usefulness for measuring the interception of precipitation in stands of cultivated plants.
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.