Уміст і склад легкорозчинних солей в алювіальних ґрунтах заплави р. Гнилиця

Abstract

Досліджено вміст і склад легкорозчинних солей в алювіальних ґрунтах заплави малої річки Гнилиця басейну р. Сіверський Донець. Установлено, що досліджувані алювіальні ґрунти сильно і дуже сильно засолені. За аніонним складом тип засолення переважно – гідрокарбонатно-сульфатний та сульфатний. За катіонним складом тип засолення – натрієвий

Исследовано содержание и состав легкорастворимых солей в аллювиальных почвах поймы малой реки Гнилица бассейна реки Сиверский Донец. Установлено, что исследованные аллювиальные почвы сильно и очень сильно засолены. По анионному составу тип засоления, преимущественно, – гидрокарбонатно-сульфатный и сульфатный. По катионному составу тип засоления – натриевый.

Two leading processes take part in the formation of floodplain soils: meadow and alluvial. The result of their combined effect is the formation of alluvial soils. They form relatively quickly, reaching significant development over several decades. Therefore, these soils are one of the most valuable components of the land fund of Ukraine. One of the most influential factors of differentiation is halogenesis. It is manifested in the type and quality of soil salinization and depends on zonal climatic, geomorphological and geological conditions of the floodplain. The quantitative composition of salts depends on the presence of floods, hydrothermal conditions of the year, the relief of the floodplain, vegetation, and other factors, as described in the literature. The accumulation of salts in the soils of floodplains of small rivers obeys general laws that are adjusted by local conditions. A significant place is occupied by regulated flow, the absence of floods and intense anthropogenic pressure among them. The complexity and specificity of the formation of alluvial soils of floodplains of small rivers impede their study. In this connection, the study of this issue is relevant and necessary. The soil field of floodplains of small rivers plays an important role in maintaining the stability of higher order river basin landscapes. The field phase of the research was carried out within the floodplain of the Gnilitsa river basin of the Seversky Donets river in the territory of the Zmievsky district of the Kharkov region. The Fluvisols Umbric Salic formed within the riverine part of the floodplain. The Gleysols Histic Salic was formed within the central floodplain. A Gleysols Endosalic was formed in near-terrace decline. Sampling was carried out in mid-July by standard methods. Standardized methods were used to analyze the salt composition of the aqueous extract. The alluvial soils of the floodplain of the Gnilitsa River had the same salt composition of the water extract a regardless of the part of the floodplain and depth. The Fluvisols Umbric Salic soil of the riverine part of the floodplain changes the type of salinization with depth. It is hydrocarbonate-sulfate according to the anionic composition for the upper horizon. In the deeper horizon - sulfate, then - again hydrocarbonate-sulfate. It is shifted towards a purely bicarbonate type of salinization in the parent rock horizon. The salinity type throughout the profile is sodium according to the cationic composition. The degree of salinization of this soil is very highly saline. The Gleysols Histic Salic soil of the central floodplain has a sulfate type of salinization according to the anionic composition over almost the entire profile. An exception is the horizon with a depth of 27-42 cm, where the type of salinization is hydrocarbonate-sulfate. It has a sodium type of salinization according to the cationic composition. This soil is highly saline. The Gleysols Endosalic soil of the pre-terrace decrease in the anionic composition of the water extract has a sulfate type of salinization, and in the cationic composition it is sodium. This soil is classified as highly saline by gradation of salinity by the amount of salts in the upper horizon. A differentiation of alluvial soils is observed depending on the part of the floodplain and depth according to the sum of readily soluble salts. The largest amount of salts was found in the soil of the near-terrasse decrease, and the smallest – in the soil of the riverine part of the floodplain. This indicator decreased with depth in the soils of the near-terrace part of floodplain and in the near-river bank, and in the soil of the central floodplain it increased.