Technique for preparation thin sections of structural soil aggregates of certain size fractions

Morphological properties of poil aggregate aer developed in the process of pedogenesis and reflect the complex of structure formation processes. The peds' size, shape, and internal structure are peculiar to each corresponding soil type and genetic horizon. The technique proposed allows preparing thin sections on every sizes of structural units and, in contrast to known methods, it provides not only a ped immobilization in the mass of fixing material, but also pore space saturation with natural resin. It is also possible to prepare the sections with marking of large aggregates orientation in space; it requires application of gypsum marks on the aggregate surface in the process of their sampling from the soil profile. The technique modified consists of following stages: selection of aggregates with required fractions; preparation of sections with separate aggregates larger than 5 mm; preparation of sections with aggregations smaller than 5 mm. In preparation of aggregates larger than 5 mm, a technique similar to that of preparing large soil block samples is used because it makes possible to process each soil aggregate separately. Another approach is required for processing of structural units up to 5 mm in size because it is impossible to prepare a section of individual issue with this size. The problem is solved when the units are saturated and processed not separately, but as a whole block sample which include a mass with peds of separate fraction. For this purpose, it is required to prepare cups comprised of walls from thick paper and a gypsum bottom. For preparation the caps use a gypsum in the form of fine white powder rapidly solidified in addition of water in a certain proportion and forms a firm bottom of the paper сup. Cut out a square of 4×4 cm in size and a strip from thick paper and glue them together to gain a tube of 5 cm in height and 1.5–2 cm in diameter (i.e. 10×5 cm). Apply on the paper squares a prepared gypsum mass sufficient to retention of the paper tube until gypsum hardening. Fill a fraction of aggregates into the prepared cup in one-third of its height and cover it with prepared fixing substance with solvent. Saturation is carried out in accordance with the standard technique of section preparing using natural resins (Gagarina, 2004). After complete saturation, paper cups with a mass of aggregates in them turn into monoliths that should be processed in the same way as large soil samples. As a result of all operations, significant number of structural soil aggregates with same sizes may be found within the section plane.

Electrophysical characteristics and dielectric constant of soils of northern natural forests of Ukrainian steppe zone

Currently in soil science the search for new methods and technologies for soil research is relevant, which in a short time allows to receive a large amount of information about its condition with the lowest financial cost. Methods for determining electrophysical parameters and dielectric constant of soils are conforming to these requirements. As a result of the investigations, it was found that the upper horizons of the soils of Glubokiy ravine, located in the Ukrainian steppe zone (Novomoskovsk district, Dnipropetrovsk region, Ukraine), differ to lower values of electrical resistance and dielectric constant compared to the lower horizons. The upper horizons are characterized by increased values of electrical conductivity, mineralization and salinity compared with the lower horizons. Sudden changes in the values of all investigated parameters at the boundary of the eluvial and illuvial horizons were found in Luvic phaeozem of northern exposition of ravine and in Luvic gleyic phaeozem of thalweg. In the Luvic phaeozem of the forest northern exposure of the ravine and in the Luvic gleyic phaeozem of the leveled area of the ravine, sharp changes were found in the values of all the investigated parameters at the boundary of the eluvial and illuvial horizons. In the eluvial horizons of Luvic phaeozem, which bordering on the illuvial horizons, a sharp increase in the dielectric constant is observed. The upper horizons of Calcic chernozem of the northern ravine exposition are characterized by increased values of electrical resistance, electrical conductivity and dielectric constant, as well as lower values of mineralization and salinity compared to the upper horizons of Calcic chernozem of the southern ravine exposition. The upper horizons of the Luvic phaeozem of the forest north exposition of the ravine are characterized by higher values of electrical resistance and dielectric constant compared to the upper horizons of the Luvic phaeozem of the forest south exposition of the ravine. In terms of electrical conductivity, mineralization and salinity, Luvic phaeozems practically don’t differ. The upper horizons of Luvic phaeozems are characterized by lower values of electrical resistance and dielectric constant, as well as higher values of electrical conductivity, mineralization and salinity compared to Calcic chernozems. The results obtained indicate that the highest content of organic matter and water-soluble compounds, as well as the best structurally-aggregate composition, and also the best structural-aggregate composition is characteristic of forest chernozem. This is due to the one that formed on the southern exposition of the ravine and which is characterized by the lowest values of dielectric constant and electrical resistance, as well as the highest values of electrical conductivity, mineralization and salinity.

Hydrological constants and water regime of a Calcic Chernozems in the zone of true steppe of Ukraine

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.

Physico-chemical determinant parameters in the color of vertisolization and tirsification processes

A statistical analysis is carried out on the influence that certain physico-chemical parameters exert on tirsification and vertisolization pedological processes that occur under certain geomorphological conditions in Andalusia region (Spain). Both processes occur on a parent material with high contents in smectitic clays, massive and uniform and contrasting climatic conditions where periods of humidity and those of drought alternate. Chromic Vertisol (tirsificated) versus Calcium Vertisol (vertisolizated) (FAO, 2015) shows a greater interrelation between parameters given its greater weathering. Organic carbon controls a large part of its physical-chemical processes where the lateral washing of salts and carbonates together with manganese, always in a lower concentration than iron, play a definitive role in the blackening of its horizons. The chemical fertility is always low and the geomorphological conditions seems to account for its agricultural capacity.

Soil thermal properties of forest biogeocenoses in steppe zone as a diagnostic indicator of their soil genesis

Soil is a specific natural body, which is characterized by a number of features due to which it differs from living organisms and rocks. One of these features is its thermal properties. The most important thermal properties of the soil are thermal conductivity, thermal capacity and thermal diffusivity, which reflect the specific features of the set of properties inherent in different soils. As a result of the studies, the existence of a direct relationship between the values of thermal conductivity and thermal diffusivity of Calcic Chernozem and the content of the silt fraction in them, as well as between the thermal capacity and the content of organic matter in them. The established relations do not appear clearly in Luvic Chernozem and Chernic Phaeozem. The maximum thermal properties for Luvic Chernozem and Chernic Phaeozem were found in the eluvial horizon, which in the lower part borders on the illuvial horizon. The eluvial horizons of Luvic Chernozem and Chernic Phaeozem are characterized by lower thermal properties compared with the illuvial horizons. The thermal properties of soils can be used to clarify the distribution characteristics of the silt fraction and organic matter along the profile, as well as determination of the intensity of eluvial-illuvial processes. The establishment of these soil features is an important characteristic of their soil genesis, which is especially important for chernozem soils under forest vegetation.

Soil salinization processes in small-lake Ballestera wetland ecosystem (La Lantejuela, Seville, Spain)

Salinization processes in soils with thermo-mediterranean-semiarid conditions within a confined environment (basin closed) are studied in Natural Reserve Ballestera small-lake ecosystems (Seville, Spain). Methodologically it is carried out a geopedological catena integrated by five drilling-profiles with depths between 0.20 and 1.50 m. A total of 21 pedo-sedimentary samples have been characterized through pH, electric conductivity, carbonates contents, magnetic susceptibility and texture determinations. The results show the presence of two different phases in the geopedological evolution of the ecosystem: one of them is previous to the geomorphological constitution of the existing wetland, characterized by carbonates and salts lateral lixiviation processes (vertisolization-tirsification processes determinant of a special black color in the soil), and the second one, later and current, distinguishing processes of salt accumulation (saline brines) and surface crust formations (saltcrete) of halite and gypsum with high value of electric conductivity (salinization and hydromorphic processes).

Landscapes of loessial islands in high Novgorod-Siversky Polissia

The territory of Novgorod-Siversky Polissia is characterized by natural conditions as a province of mixed forests, where soddy-podzolic soils of low fertility have formed on loamy sandy and sandy deposits. However, on the high plateau the Desna River valley right bank, there are Novgorod-Siversky and Ponornitsky loessial islands with fertile dark-colored soils (Opillia). They were formed in rather damp and cool conditions, which is natural for the forest zone. However, their landscapes by the property of the components have a forest-steppe nature. On the plateau, in the Novgorod-Siversky Opillia, eolian loessial is located, which led to the formation of dark gray podzolized soils and chernozems leached and podzolized mainly with a humus-degraded arable layer. On sufficiently large areas near localities Pontornytsya, Pokoshychi and Desnianske there was happened loessivation and silt-loam sandy. Fertile gray forest soils were formed here – a kind of Opillia region. During the large-scale survey and mapping of Ukraine's soils in 1957–1961, dark-colored soils of loessial islands were defined predominantly as dark gray podzolized. However, our recent studies have proved the widespread distribution of leached chernozems and podzolized opіlsky chernozems. On strongly eroded slopes of the right-bank native shores, we have remnants of the suboak forest, which indicate the forest-steppe nature of the landscapes. In virgin areas, unlike sandy areas, a thick bean-grass-mixed grass cover, including indicators of forest-steppe. The Opillia area with chernozems and other dark-colored soils is a major agrarian resource of the region. But gray forest soils also belong to the most valuable land in Polissia. On gray forest soils, cereal crops are grown by 4–5 centners per hectare higher than those on typical of the Polissia sod-podzolic soils. Loessial islands are common in southern part of Novgorod-Siversky Polissia, in particular, on the Desna River valley right bank. Landscapes are diverse in properties of components – the nature of loessial species, geological foundations, features of soil cover and relief. They are united by forest-steppe features of soil cover, the presence in the central part of Opilia – fertile dark-colored soils, including chernozems with signs of relic steppe phase in their development, meadow-steppe composition of herbaceous cover on virgin areas and the presence of remnants of the suboak forest. These are large fragments of the Forest-Steppe in Polissia, which have a high natural resource.

Geopedological processes in Doñana National Park (Spain)

On the dunes of Doñana National Park (Spain) and in areas coinciding with a Juniperus turbinata evolved savin forest, the presence of Arenosoles with dark colours, presence of clays and levels enriched in iron and manganese at about 60 cm depth are detected. Its physicochemical and mineralogical characterization has been carried out following the usual methodology of our laboratory. These soils (profile SOJ-2) show a higher level of magnetic susceptibility, vermiculite biogenic clays and mild luvic and chromic properties in an B incipient horizon formation. All this denotes a greater pedogenesis that usually affects to the aeolian littoral sheet that characterizes to this important natural reserve. The phytostability that Juniperus turbinata offers would be the responsible for this pedogenesis, and the evolution experienced by the physicochemical parameters with the depth show an intense lateral washing of sand (sand washing). The different patterns of distribution of the medium sands along the profile could be used for the differentiation between different environmental conditions.

Ecosystem approach to the assessment of land reclamation on the example of Zaporizhzhskiy manganese ore quarry

Mining industry is the one of the powerful factors leading to the degradation of native ecosystems. Disturbed ecosystems developed instead the native may be remediated using certain reclamation techniques. The purpose of this work was assessment of the remediation quality within Ordzhonikidze Ore Mining and Processing Integrated Plant on the possibility of their economic use and suitability for the existence of soil biota, as well as providing recommendations for further rational economic use. Technical remediation of the surveyed area included such stages as removal of topsoil with gross method, followed by its storage in piles; reformation and levelling of overburden above-ore dump disposed in the exhaust space of career by gross way; keeping of levelled rocks up to 3 years with the purpose of their subsidence; surface repair after subsidence; application of humic layer; ploughing of reclaimed lands. Assessment of soil quality was carried out by comparing a quality score of reclaimed soils with a quality score of zonal soil. Data collection and processing were carried out on values of humus layer thickness; humus content in filling top layer; content of physical clay in topsoil and subsoil; granulometric composition of one-meter thick fill layer; topsoil and subsoil salinity; composition and properties of underlying rocks. As a result of mining operations, topsoil of remediated soil is depleted in chemical elements necessary for plant growth; as a result, the soil becomes more calcareous, and contains humus 1,5–2 times less than that in topsoil of undisturbed soil. Topsoil thickness is on average 58 cm. Humus content in the filled layer on average is 2.2%. Mechanical composition of the arable layer is middle loamy. The soil is compacted below the plow pan. Mechanical composition of the underlying rock is fine-textured. Salinization with water-soluble salts above the toxicity threshold in the arable layer of the studied soils was not found. Before agricultural use of reclaimed lands, it is essential to repair it with the techniques of biological reclamation. This is achieved through cultivation of salt-resistant perennial grasses for 3–5 years.

Indicators for pedogeochemical barriers of heavy metals’ migration

The aims of this study were to substantiate indicators for pedogeochemical barriers of heavy metals’s migration. The concept of pedogeochemical barriers of heavy metals’migration. Pedogeochemical migration barrier is part of the soil horizon or soil profile, where, as a result of special pedosubstantsiya availability and certain pedogeochemical reactions percolation, there is a significant accumulation of some chemical elements. These barriers act as a «substation-reactionary phenomenon». Pedogeochemical migration barrier grouped into five types: mechanical A, physical (sorption) B, physicochemical (ion exchange) C, chemical D and biological E. Indicators of geochemical migration barriers. To assess the geochemical barriers to migration, A. I. Perelman suggested using barrier contrast indicators and the barrier gradient. Wherein, the barrier contrast is calculated as the ratio of the chemical element concentration on the barrier to its quantity up to the barrier. Barrier gradient is the ratio of soil differences before and after the barrier to its length. Indicators of pedogeochemical migration barriers. In soil science, as the analogue of the barrier contrast are: the contrast ratio, the coefficient of intra-profile differentiation, alluvial-accumulative coefficients. As an analogue of the gradient barriers, there are indices of absolute and relative gradients of pedogeochemical migration barriers. Indicators of Pedogeochemical migration barriers manifest that in the chernozems of ordinary and southern at Kryvyi Rih areas, the accumulation of heavy metals in the humus transition and humus accumulation horizons has been revealed. Wherein, the more intensive action of soil migration barriers is naturally revealed in chernozems of ordinary, in comparison with chernozems southern.