Морфолого-генетична та агрономічна характеристики контрастних за засоленням ґрунтів солонцевого комплексу Приорілля

Abstract

The article presents the results of field and laboratory studies on the determination of the morphological, genetic and agronomic characteristics of the soils of the Solon complex of Prioril, contrasting in terms of salinity - the establishment of the peculiarities of the morphological structure of the profiles, the granulometric composition, and the parameters of the main agrochemical, salt and physicochemical parameters of the salt marsh of the meadow-black earth shallow salt marsh and black earth-meadow soil - as typical components of the salt complex of the Oril river valley. Standardized field survey and laboratory-analytical methods were used. It has been established that manifestations of halogenation increase with depth in the Luchno-chernozem salt marsh. Alkalinity in the humus-iluvial horizon increases to a strong degree, in deeper horizons - to a very strong one; the degree of salinity increases to medium, strong, and finally to very strong in the bedrock. According to the depth of the upper horizon of salt accumulation, this soil is classified as saline. The content of absorbed sodium in the humus-iluvial and illuvial horizons corresponds to the "saline" gradation. The chernozem-meadow soil is non-saline according to the content of toxic salts in the entire profile, there are no signs of physical and physico-chemical salinity. The content of the silt fraction in the salt marsh profile increases with depth and reaches its maximum value in the illuvial horizon, which is typical for salt marshes and is explained by the redistribution of soil colloids in the profile, the granulometric composition of the salt marsh in the humus-eluvial and illuvial horizons is light clay, in the humus-illuvial - medium clay. The profile of the chernozem-meadow soil is also heterogeneous in granulometric composition, which is heavier from medium loam in the humus horizon to heavy loam in the transitional horizons. The reason for this may be ancient alluvial processes that formed the soil-forming rock of the single-forest terrace. The content of humus in the salt pan in humus-eluvial and humus-iluvial horizons is average, the content of mineral (nitrate and ammonia) nitrogen is very low. The content of mobile potassium turned out to be elevated, and the content of mobile phosphorus was very high. In the chernozem-meadow soil, the content of humus in the humus arable horizon is high, in the first transitional one, it is average. The content of mineral nitrogen is low. The content of mobile phosphorus exceeds the upper limit of the high level by 3.5 times, and mobile potassium by 3.1 times, which is typical for the soils of closed depressions and is a consequence of long-term accumulation of surface runoff waters. Conclusions. The salt marsh complex of Priorillya with the number of salt marshes in the soil cover of about 50% is typical for the southern part of the Middle Forest Steppe in terms of the structure of soil profiles and soil halogenation. A characteristic feature of the studied salt marsh complex is the significant contrast of its components in terms of halogenation manifestations: at a short distance there are salt marsh highly saline salt marsh and leached chernozem-meadow soil without physical and physico-chemical signs of salinity.