IMPACT OF THE DEGREE OF ANTHROPOGENIC DISTURBANCE OF NATURAL STEPPE PHYTOCENOSES ON THEIR PRODUCTIVITY AND ACCUMULATION OF MORTMASS

Abstract

Introduction. The influence of anthropopressing on the formation of the aboveground and underground biomass and the combination of these factors on the accumulation of litter in steppe phytocenoses were studied. A comparative analysis of natural plant communities with the ones located in the area with the absolute reservation regime was carried out. Quantitative relations between the aboveground biomass and litter depending on the species composition of phytocenoses, edaphic conditions and anthropogenic pressure were found.The aim of this article is to analyze the productivity and accumulation of mortmass in steppe phytocenoses depending on anthropogenic pressure in order to establish the specifics of their functioning in the conditions of Southern Kryvyi Rih Area.Methods. The method of 1 m2 mowing squares in 20-fold repetition with definition of absolutely dry weight was used to study the aerial part of grass stand phytomass and mortmass. The distribution of the underground organs of the grass stand in the soil pedons was determined by washing the soil monoliths in I.Kh. Uzbek modification. The weight and volume of the roots were determined. According to the preliminary data, we calculated the surface area and total root length. The data obtained were processed by the method of variation statistics.Results and conclusions. As a result of the conducted studies, it was ascertained that the productivity of steppe phytocenoses and the accumulation of litter in them depends on the dominant species in their composition, the conservation regime, the position in the relief and pasture digression. The dominant of these communities prevails in all monitoring sites in the studied phytocenoses in the phytomass, with the species with different biomass indicators being subdominant. The highest indices of the aboveground, underground phytomass and mortmass are characteristic of the plant communities of the protected area, which should be considered as the effect of reserve-pathogenic mesophytization. Productivity and mortmass indicators for steppe communities on the slopes depend on the biological characteristics of the dominant in the phytocenosis, the position in the relief, the degree of rockiness of the substrate and the anthropogenic load. The most root-saturated soil horizons in all studied phytocenoses are the ones at depth of 0–10 cm, where the main root mass of herbaceous plants is located. Also, this soil layer is characterized by high values of volume, surface area and length of roots. Keywords: steppe; plant communities; productivity; mortmass; reserve regime; anthropopressing; South Kryvyi Rih area.