Soil natural radioactivity of northern variant ravine biogeocenoses of Ukrainian steppe zone

Abstract

Ravine biogeocenoses in the steppe zone of Ukraine are a unique natural phenomenon. Under these natural forests for many millennia formed a specific kind of soil – forest chernozems, which differ in a number of ways from the zonal chernozems. Today in the scientific literature you can find information about such properties of these soils as organic matter, structural and aggregate composition, lessivage, micromorphological features. However, the natural radioactivity of forest chernozems remains virtually unexplored. Our work is devoted to the establishment of the peculiarities of the natural radioactivity of the soils of ravine biogeocenoses. The soils of the Hlyboky ravine, which according to the classification of O.L. Belgard belongs to the northern version of the ravines of the steppe zone of Ukraine. As a result of the performed researches it is established that the surface horizons of chernozems of forest southern and northern exposures of the ravine differ in reduced values of ashing coefficient, which indicates an increased content of organic matter in them compared to other horizons of the studied soils. Eluvial horizons are characterized by reduced values of natural radioactivity compared to illuvial, which indicates increased sorption by small particle size fractions of radioactive elements compared to larger fractions. The maximum values of natural radioactivity were found in the lower genetic horizons of the studied soils. This indicates that the source of radioactive elements is the parent rock from which the soil was formed. Organic substances and their ability to bind radioactive elements are characterized by a smaller contribution to the natural radioactivity of soils compared to small particle size fractions and parent rock. The distribution of natural radioactivity values by soil profile is determined by the peculiarities of soil genesis of each individual soil type and to some extent can reflect them.