CHARACTERISTICS OF WEED SPECIES COMPOSITION IN POTATO PLANTINGS UNDER CHANGING ANTHROPOGENIC IMPACT

The south of the Non-Chernozem Zone of the Russian Federation is a zone of traditional potato growing. One of the reasons for the decrease of its productivity is fairly high weed contamination of the crop. The research goal was to determine the characteristics of the species composition of weed cenosis of potato plantings at different levels of anthropogenic impact as the basis for developing an efficient system for protecting potatoes against weeds. To analyze the dynamics of weeds in potato plantings, geobotanical data from 1929-1932, 1936-1938 and 1981-1983 were used. Our own surveys were carried out from 2014 through 2022 in field expeditions. Weed counting determined the weed number and species diversity. The similarity and rank correlation of weed flora at different stages of research were calculated using nonparametric statistics. During the period of extensive farming, 66 weed species were identified in potato plantings. In the second half of the 1930s, 54 species were identified; and during the period of intensification of agriculture, the number of weeds decreased to 32 species. Currently, 79 species have been identified. At all studied periods, the core of the segetal flora consisted of representatives of the families Poaceae (10-42%), Amaranthaceae (6-15%) and Asteraceae (10-38%). Under the conditions of extensive farming, creeping-rooted species prevailed in the crops in terms of the number of plants per unit area (50 pcs m2). In potato agrocenoses, there is a tendency to increase the number of adventitious plants. This, in turn, requires regular monitoring and control of their numbers in order to prevent the naturalization of the most harmful ones. Thus, the level of anthropogenic load is the main factor in the change of the taxonomic composition of weeds in potato agrophytocenoses. The results obtained may be used to develop strategies for weed control at the modern stage of agriculture.