DYNAMICS OF THE SEGETAL FLORA OF THE SOUTH OF THE NON-CHERNOZEM ZONE OF THE RUSSIAN FEDERATION WITH A CHANGE IN THE LEVEL OF ANTHROPOGENIC IMPACT

The article presents a comparative analysis of the taxonomic structure of the segetal flora of the south of the Non-Chernozem zone of the Russian Federation over a 90-year period of time. The segetal flora is represented by weeds of agrophytocenoses of the main cereals, leguminous and row crops, perennial and annual grasses. The maximum species richness of the segetal flora was established for the period of the minimum anthropogenic load of the 1930s - 166 species. The minimum number of species was noted for the segetal flora of the 1980s, a period characterized by maximum anthropogenic loading. The core of weed species in all periods were representatives of the Asteraceae, Poaceae, Brassicaceae, Fabaceae, Lamiaceae, Caryophyllaceae, Scrophulariaceae families. When comparing the species composition of agrophytocenoses of individual crops, it was found that the increase in anthropogenic load contributes to an increase in the coefficient of similarity between them. The coefficient of similarity in all periods of research was quite high between cultures similar in biology and cultivation technology. A pool of segetal species was identified that maintained a high population density during all periods of research. They are treated as perennial (Elytrigia repens (L.) Nevski Convolvulus arvensis L., Cirsium setosum (Willd.) Besser., Equisetum arvense L) so are juvenile (Chenopodium album L., Amaranthus retroflexus L.) weed species. At the present stage of the phlorogenesis of segetal vegetation, there is an increase in the proportion of adventitious species of its components. Stable populations for the region were noted in such adventitious species as Galinsoga parviflores Cav., Erigeron annuus L., Heracleum sosnowskyi Manden.