STATE OF RENDZINAS (RENDZIC LEPTOSOLS) OF THE PODILSKI TOVTRY

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Problem Statement and Purpose. The role of soils in the global processes of functioning of natural systems is largely determined by the peculiarities of the formation of different groups of organic matter, which plays the role of a limiting factor, the bioproductivity of ecosystems. Water-physical and morphological properties of soils, their erosion resistance, etc. depend on its composition and dynamics of renewal. The territory of Podilsky Tovtry is characterized by unique soil formation conditions, where specific spatial change of soil-forming factors determines the formation of different morphological structure, properties, dominant soil-forming processes, stages and directions of ontogeny of rendzin and pararendzin. The aim of the study is to establish the peculiarities of the formation of organic matter rendzin Podilsky Tovtry, based on the characteristics of their humic condition. Data & Methods. During 2015–2021 y. we laid down 5 modal sections. The system of soil sections represents rendzinas in different lands: arable lands, fallows and virgin areas under forest and meadow phytocenoses. Soil samples were taken in layers (every 10 cm). Laboratory and analytical studies were performed by conventional methods to simplify comparisons of data and their correlations with previous studies of other scientists, in particular the total humus was determined by Tyurin's modified by Nikitin (DSTU ISO 14235: 2005), structure density – by the method of cutting rings. Results. Among the rendzinas of the Podilsky Tovtry in terms of humus content, three groups are clearly distinguished: rendzins formed on the tops of tovtry on the eluvium of lithotamnium and serpulo-mohovatnyh limestones and are in a virgin state under meadow-steppe vegetation. The average humus content in the upper Hca horizon here reaches 12–15% (in some samples about 17%) and decreases sharply down the profile, reaching the minimum values in the lower transition horizon Phca 2.8–3.5%. This is due to the significant influence of calcium carbonates, and the accumulation of "rough" humus of the moder type; rendzina, formed on the same species (but strongly weathered), which are in later stages of development under forest vegetation, as well as rendzina, which have undergone degradation due to long-term agricultural use. The average humus content in the upper Hca horizon here reaches3.9–4.5% and gradually decreases down the profile, reaching the minimum values in the lower transition horizon Phca 1.12–2.25%; brown rendzins and pararendzins of the Tovtr slopes, formed on the forested eluvium-deluvium of lithotamnium and serpulo-mohovatnyh limestones and carbonate polygenetic loams. The average humus content in the upper Hca horizon here is in the range of 2.7–3.0% and graduallydecreases down the profile, reaching the minimum values in the lower transition horizon Phca 0.3–1.2%.