Features of the phytocenotic interaction of cultural and segetal species of plants in organic agrocoenoses

To establish the regularity of the formation of groups of segetal vegetation in crops of corn and leguminous crops depending on the method of main tillage and the technique of growing these crops, as well as the main indicators and parameters of the phytotoxic interaction of cultivated plants and weeds. Methods. The research was carried out during 2021 – 2023 in a stationary field experiment on a gray forest coarse dusty light loamy soil with a humus content in a layer of 0–30 cm. Narrow-leaved lupine–buckwheat against the background of two methods of main cultivation (shelf 20–22 cm, shelf-less to a depth of 10–12 cm), with sowing of crops in their pure form and binary sowing with a bean component. Results. The greatest increase in the vegetative mass of the crop was obtained in the oat agrocenoses, as well as in its simultaneous cultivation with vetch – 797 and 826 g/m2. The increase of this indicator, compared with single-species sowing of oats, indicates an increase in the competitiveness of binary crops concerning segetal species. The highest anti-weed effect was established against the background of plowing at 20–22 cm in monospecies sowings of winter rye and a binary mixture of winter rye and winter vetch, where the amount of weed coenosis was 18 and 13 pcs/m2, respectively. An important factor in our research was the method of sowing for the crops under study, for example, with binary sowing of rye, the index of competitive pressure was the highest and amounted to 4.33% for shelf cultivation at 20–22 cm and 6.28% for disking at 10– 2 cm, which is compared to other versions of mixtures of the studied cultures, which is due to the higher competitiveness of this culture. That is, the leguminous component is an additional measure to increase the phytocenotic activity of the main crop against weeds. Conclusions. Research has established that the level of weediness in crops depends on the biological characteristics of crop rotation and the conditions under which they are grown, this allows us to recommend the use of the characteristics of winter rye to have a coenotic effect on weeds using the method of main soil cultivation as plowing for 20–22 cm, which reduces their harmfulness in these crops by 85.4% in a pure crop and 90.1% in a mixture with winter vetch.