The characteristics of important water-physical properties and water-balance monitoring results for Calcic Chernozems located in the zone of true steppe were provided. The differences between soil-hydrological constants in carbonated loess-like loam and organogenic horizons were established. The results of water-balance monitoring showed that the moisture has uneven distribution along the soil profile, and most of the active moisture (more than 90%) was accumulated within the range of depths from 0 to 150 cm. During the entire calendar year, the soil is characterized by a lack of moisture available to plants. There are no periods free from water deficit.

A detailed study of the relationships between all components of each biogeocenosis is needed for its in-depth investigation. According to the concept of biogeocenoses developed by V. M. Sukachev, soil is one of the five components of biogeocenosis being its resulting unit. Soil is a bioinert component body of biogeocenosis. Playing the role of a subsystem, it is characterized by self-regulation, stability, direct and feedback mechanisms, self-restoring fertility, a specific biological cycle of substances and energy flow against the background of a specific natural geographical area. When the soil testing, its chemical, physical, water, micromorphological properties should be determined, and, above all, a total humus content and quality. Humus affects all important soil properties. In fertility, its essential role consists in a nutrient source as a factor that has a physiological effect on plants. A role of humus in improving the physical, thermal and water properties of soils is well-known. The total content and group composition of humus are also determined during the diagnosis and classification of soils. For a more detailed description of humus, Grishina and Orlov proposed a system of indicators of soils humus condition. This is a level of humus content and reserves, its profile distribution, type of humus, degree of humification, etc. In this work, we made an attempt to diagnose the soils of ravined biogeocenoses and steppe virgin lands in Dnipropetrovsk region on the basis of a number of the above parameters. To compare, the common steppe virgin chernozem and forest chernozems of the northern and southern variants of the ravines were used. The study was carried out in the fresh linden-ash oakery (the Kapitanovsky Bayrak) and in the fresh maple oakery (the Viyskovoy Bayrak) occured in the middle part of the slopes of the northern exposition. The paper presents data on the study of the ravined forest biogeocenoses influence on the total content and qualitative composition of soil humus in the northern and southern variants of Dnipropetrovsk region in comparison with the steppe virgin soil. It was established that the total humus content and reserves in the layer of 0–20 cm increased and varied from moderate to high under the influence of ravined forest vegetation; the type of humus turns from humate to fulvate-humate, which has a positive effect on plant growth and development, as it makes nutrients more mobile and available to plants. Under the influence of forest vegetation in the ravines, the soil humus condition improved, namely, the total humus content and reserves in the 20 cm layer varied from moderate to high, and the type of humus turned from humate to fulvate-humate. Our data confirmed  O. L. Belgard and A. P. Travleev provisions that forests in the steppe zone effect positively on soil properties, in particular their humus condition, in contrast to the forest zone.

На території степової зони України з допомогою GPS навігатора та нівеліра встановлено координати вершин, конфігурацію меж, висоту, довжину, ширину 400 ярів, балок і байраків. Визначено вміст заліза у шарі 0–50 см. Отримані дані імпортовано у QuantumGis і нанесено на карту розораності земель України. Осередки скупчення досліджуваних об’єктів виявлено у центральній та східній частинах Степу. Аналіз причин показав комплексну дію чинників. За рік спостережень виявлено, що площа кожного яру зросла у середньому на 5 м², висота – на 7 см, довжина – на 24 см, ширина – на 21 см, концентрація Fe знизилась на 20 мг/кг. Основні причини – значні опади та нестійкий трав’яний покрив. Площа балок зросла на 1 м², висота – на 4 см, довжина – на 14 см, ширина – на 9 см, концентрація Fe залишилась без змін. Унаслідок того, що деревні рослини стримують розвиток ерозійних процесів і збагачують ґрунти мікроелементами, у байраків спостерігається зменшення висоти на 1 см та зростання концентрації Fe на 24 мг/кг, значення інших показників не змінились. У середовищі QuantumGis створено електронні карти щільності та поширеності ярів, балок і байраків у степовій зоні України. За їх допомогою визначено залежність між досліджуваними процесами та природними умовами, межові кути повороту, площу яружно-балкової ерозії. Створено проект бази даних щодо вмісту мікроелементів та особливостей їх міграції за байрачним профілем із метою подальшого застосування у процесі розроблення необхідних заходів боротьби з ерозією.

As known, the natural seed renewal process flows under the influence of spontaneous climatic and biotic factors in forest biogeocoenoses. In this process in the conditions of steppe Ukraine the role of forest litter and the rodents’ activities is increasing especially. Investigations were carried out in natural and artificial forest biogeocoenoses of Prisamaria and Kirov forestry, as well as in reclaimed areas of the Western Donbass. Stocks of forest litter and the number of rodents (common vole, house mouse, field mouse etc.) have been studied according to conventional methods. It was found that in contrast to humid conditions in natural forests of steppe Ukraine the litter contributes to friendly seeds germination of main tree species ‒ English oak and Scotch pine. Thus the forest litter has a beneficial effect on such an important in the life of the forest process as the natural seed renewal. Only in rare cases when the litter thickness exceeds 4-5 cm (in the conditions of steppe such type of litter is very rare), there may be obstacles for seeds germination. The optimum number of rodents in natural systems without prejudice to homeostasis of biosystems can range between 50-80 individuals/ha. Significant increases in the number of rodents cause a decrease in natural regeneration. A trophic role of rodents should be considered as a positive factor in the young artificial forest reclaiming plantations.

The relationships between the productivity of herbage as one of the structural elements of forest biogeocenosis with the nature of the formation and chemical composition of the forest litter and the activity of mouse-like rodents in linden and ash flood oak grove of Prysamar’ya were investigated. It was found that leaf-litter affects to the species composition and the degree of development of grass of investigated biogeocenose. It was revealed that the trophic removal of herbage phytomass by mouse-like rodents in the initial period of vegetation promotes its products. As a result, the above-ground herbage on rodent habitats increases by 1.2 times. The alienation of above-ground herbal phitomass in natural conditions under the influence of mouse-like rodents in the middle of the vegetation season increases in areas devoid of rodents’ influence by 1.05 times. It was found that in the final vegetation season, the above-ground herbage at the rodents’ exposure sites decreases by 1.3 times. It was investigated that the above-ground herbage for the whole vegetation season in the natural conditions of the flood oak grove was 115.4 g/m2, and in experimental areas, devoid of rodents’ exposure was 124.0 g/m2. Thus in the study biogeocenosis the value of herbage productivity was under the influence of mouse-like rodents and it reduced to 1.07 times during the whole growing period. In turn, the grass contributes to the increase in stocks of leaf-litter, ash elements including trace elements in forest litter. The quantitative proportion of herbaceous plants in leaf-litter and the chemical composition of grass in two synusias (wild chervil and starwort) were studied. It was revealed that the air-dry weight of the above-ground parts of herbage in synusia of wild chervil was higher than in synusia of starwort. It was determined that the accumulation degree of individual trace elements varies in different species of herbaceous plants. The maximum content of Mn, Pb and Cu more at wild chervil and Ti, Mo, V, Ni and Cr maximum contents were marked at starwort.