Physical Clay Research Articles

The elemental composition of soils of saline agrolandscapes of the Prichanovskaya depression and their sanitary and hygienic assessment

The elemental composition of the soil was studied in the mesorelief of the former water area of the Yudinsky stretch of Lake Chany. The study was carried out in two soil sections that are in geochemical conjugation: meadow-chernozem weakly-solodic loamy sand soil in the eluvial landscape position and meadow-marsh saline heavy-loamy soil in the accumulative landscape. Soils differ significantly in both redox and acid-base conditions: the distribution of humus in the soil profile, pH values, the content of physical clay, cation exchange capacity. Distribution of the predominant number of macroand microelements (with the exception of silicon) in the saline agrolandscape of the Prichanovskaya depression is characterized by their accumulation in the meadowmarsh saline heavy loam soil as a result of water migration and subsequent fixation in the form of slow-moving compounds. The content of elements in the accumulative position is on average 2-3 times higher than in the eluvial one. Macroelements iron and aluminum migrate down the relief in the form of sesquioxides in the composition of the clay fraction. The accumulation of calcium and magnesium is associated with the carbonatization of the soil profile. Trace elements zinc, copper, cadmium, lead are deposited on the alkaline barrier in the profile of meadow chernozem soil at a depth of 95 cm and below, in a meadow-marsh saline soil from the surface, molybdenum is concentrated in the upper horizons of the soil profile on the evaporation barrier, manganese on humus and gley meadow-bog soil, nickel and cobalt on humus and clay, chrome in salt accumulations. An imbalance of copper and molybdenum, iron and manganese, calcium and strontium is observed in the soils of both the eluvial and accumulative positions, which indicates a deficiency of molybdenum and manganese and an excess of strontium in the landscape soils in general. There is an excess of permissible sanitary and hygienic standards for the content of strontium and barium in the accumulative positions in the entire thickness of the soil profile of meadow-marsh saline heavy-loamy soil. The content of arsenic and, especially, boron exceeds the MPC values in the landscape as a whole.

The influence of soil texture on the course of volume changes of soil

Volume changes of soil associated with soil moisture changes are caused by the presence of clay minerals from illite and montmorillonite groups. Clay minerals are found in the so-called clay soil component which can be quantified by laboratory analysis of the soil particle-size distribution. Consequently, the potential for volume changes in soil can be assessed from soil texture. In our study, 172 soil samples with different textures were used to measure dependencies between volume changes in soil and changes in soil moisture under laboratory conditions. The samples were collected from 11 sites in the Eastern Slovak Lowland. On the basis of the measurements, 10 mathematical models were created to compute the correlation between volume changes of soil and soil moisture content and texture. The highest accuracy was obtained with the model which assumes the content of particles < 0.002 mm. When comparing the clay particles < 0.001 mm (colloidal clay) with the particles < 0.002 mm (colloidal + physical clay) it was also found that the particles < 0.002 mm have a larger impact on the volume changes of soil than the particles < 0.001. The inclusion of particles > 0.002 mm (silt + sand) into the models resulted in either no or only negligible refinement of the soil volume change calculations.

Characterization and Classification of Soils of the Terra da Esperança Settlement Project in Chapada do Apodi, Brazil

Soil characterization and pedological classification are essential to define its main potentials and restrictions. The objective of this work was to classify the morphological, physical, chemical, and pedological attributes of soils of the Terra da Esperança Settlement Project (TESP) in Chapada do Apodi, Brazil, and find the most sensitive attributes for distinguishing them using multivariate analysis. The research was carried out in the TESP, in the municipality of Governor Dix-Sept Rosado, state of Rio Grande do Norte, Brazil. Ten sites were chosen to open representative soil profiles: Native Forest Area 1 (NFA1), 2 (NFA2), and 3 (NFA3), Collective Area with Native Forest (CNF), Agroecological Area (AEA), Cashew crop Area (CCA) Collective Area with Pasture 1 (CAP1), and 2 (CAP2), Permanent Preservation Area (PPA), and Cajaraneira (Spondia sp.) Orchard Area (COA). Disturbed and undisturbed soil samples were collected and subjected to physical and chemical analysis for soil classification. The soils classes found were: Cambissolo Haplico Carbonatico vertissolico (NFA1), Cambissolo Haplico Carbonatico tipico (CNF, and AEA), Cambissolo Haplico Ta Eutrofico tipico (CAP2, NFA2, and COA), Cambissolo Haplico Ta Eutrofico vertissolico (NFA3), Argissolo Vermelho Distrofico latossolico (CCA), Chernossolo Rendzico Ortico saprolitico (CAP1), and Neossolo Fluvico Ta Eutrofico tipico (PPA). The material of origin of the soils contributed to the presence of a calcic horizon in the profiles NFA1, CNF, AEA, CCA (Cambissolos), and CAP1 (Chernossolos). The textural class of the soils varied from sand to clay. The Argissolo (CCA) presented acid character, high aluminum saturation, low base saturation, dystrophic character, and low cation exchange capacity, forming horizons with chemical limitations, due to its latossolico character. The most sensitive attributes for distinguishing the soil classes were related to the source material, which directly influenced the soil physical (silt and clay) and chemical (acidity, salinity, nutrient availability, and clay activity) attributes.

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.

Исследование водно-физических свойств орошаемых лугово-серых почв на опытном участке в условиях Азербайджана

Water-physical properties of the soil are not constant, they often are changed under the influence of natural conditions and agrotechnical measures. Studies show that water-physical properties directly affect the life and growth of plants. In this regard, the main tasks are to study the changes in water and physical properties of the soil under various crops in irrigated areas and to develop the systems of agromeliorative measures. As a result of researches the water-physical properties of irrigated meadow-gray soils of the experimental site at the Salyan plain were studied: physical clay – 48.2...56.79%, density of solid phase – 2.62...2.73 g/cm3, density of dry soil – 1.22...1.46 g/cm3, total moisture capacity – 31.86...43.80%, soil porosity – 46.52...53.44 %, CaCO3 –11.11...14.96%, pH – 8.2...8.6, SO4 in gypsum – 0.077...0.899%, the ratio of absorbed bases – 12.27...15.96 milligram equivalents. Researched soils have a weak and medium degree of water permeability (Kt = 5.51...8.83 cm/h the Kostyakov equation). The traditional and modern methods of irrigation (furrowing, sprinkling, drip, etc.), application of fertilizers (organic, mineral and micro fertilizers, local fertilizers, silt deposits of river waters, etc.) are recommend as agrotechnical measures in accordance with preliminary study of ratio of salts in soil.

Пространственная неоднородность свойств почв в зоне распространения островной мерзлоты (Приполярный Урал)

Пространственная неоднородность свойств почв в зоне распространения островной мерзлоты (Приполярный Урал)

Physical and Chemical Features of Slope Lands on the Southeast Part of the More Caucasus on the Example Gobustan, Shamah and Ismaillinsky Districts

The present article describes physical, chemical, and physicochemical properties of the steppificated mountain brown soils under perennial plantings by using modern irrigation technology with the aim of increasing the productivity of soils in freshwater. Corresponding norms were determined in watering of orchards on the steppificated mountain brown soils of the southeastern slope of the Greater Caucasus. Chemical characteristics of the soil taken from the experimental zones vary among gyroscopic humidity in upper layer 6,18-6,23 %, humus 4,03-4,30%, total nitrogen 0,252- 0,238%, total phosphorus 12,22-13,33 mg/kg; CO2 5,58%; CaCO3 in relation to CO2-12,70%; Ca in 100gr soil – 30,5 mg/kg; Ca-84,72-87,14%; Mg-12,86-15,28%. According to morphological characteristics of sections taken from steppificated mountain brown soils, mechanical content of this soil is heavy clay. Amount of physical clay in the upper layers of this soil vary between 67,20-69,20%, amount of clay between 34,40-39-20%, in the lower layer between 65,20-77,20%; 29,60-32,80%. Structural content of this soil, amount of structural parts higher than 1mm in the upper layer of the soil varies between 61,72-62,33% and in the lower layer between 68,05- 68,80%.

Qualitative assessment of souls in technogenic landscapes of Gorlovskiy anthracitous deposit

The paper highlights the results of Morphological studies of soils formed on the outer 30year dumps of overburden and host rocks of the Gorlovskiy deposit and leached chernozem soil. The authors found out that soil covering contains initial, organic accumulative and sod types of embryosimes. Comparative morphological characteristics of soils indicates differences between chernozems and technogenic landscape soils. The results show that soil formation increases concentration of pedogenic organic matter in the soils which is almost equal to that in the black soil. The paper represents qualitative assessment of the soils. The authors calculate the index of specific features which reveals significant differences in the contribution to total variation of different soil properties. The article shows that embryosimes formed on loose sediments are the most fertile. It is established that the level of quality value in rocky soils is determined by concentration of physical clay; in the soils formed on loose rocks it is explained by humus concentration.. The ecosystem is not in a meta-stable climax state; it is developing dynamically, being at the stage of forming sod embryosimes. Therefore, the soil and environmental condition of tailings is satisfactory, as the embryosimes have not been formed after 31 years later the initial phase of technogenesis started. Humus accumulating embryosimes are expected to be formed in the soil covering as well as dry steppe souls on technogenic eluvium and neogenic clays.

Зміна гранулометричного складу осушених ґрунтів Малого Полісся в контексті розвитку деградаційних процесів

Sod-podzolic (Albenuvisoils Gleyic), meadow (Gleyic Chernic Phaeozems) and sod (Arenosols) soils are typical for Male Polissia. In the natural state, these soils are waterlogged, characterized by unsatisfactory physical properties, unsuitable for agricultural use. After the drainage reclamation, the soils are intensively used as arable land, pastures, and hayfields. The drainage has led to a significant decrease in groundwater levels, increased the washing water regime, intensified the processes of lessivage, which affected the physical properties of soils, in particular, granulometric composition. In the reclaimed areas, aridification and deflationary processes intensified. In deflated sod-podzolic soils, the relief of granulometric composition has been reducing due to decrease in the content of sludge and fine dust in the arable horizons. Granulometric composition of soils undergoes more significant transformations as a result of the intensification of flushing water regime after drainage. The content of physical clay in the arable horizon of sod-podzolic fixed- sandy soils decreased by 1.63 %, and of the sandy loam soils – by 5.30–6.20 %. In the humus-accumulating arable horizon of meadow soils, the physical clay content decreased by 2.40–1.60 %, that of sod soils – by 1.27–6.39 %. Washing off with drainage waters of small granulometric fractions results in an increase in the content of sand fractions and facilitates the granulometric composition of soils, changes in soil gradation at the level of variety. Decrease in the content of physical clay causes deterioration of physical, physical-and-chemical, agronomic properties of soils, and therefore causes the development of degradation processes: non-structural, deflation, dehumification, degradation of water and air and nutrient regimes, aridification. This gave rise to the idea of referring to the granulometric composition facilitation of drained soils as “granulometric degradation” and classifying it as physical degradation of soils. Key words: Male Polissia, drainage reclamation, soils, granulometric composition, physical clay, granulometric degradation.

Эколого-агрохимическая характеристика содержания микроэлементов в системе почва-растение в агроценозах Омского Прииртышья

The data on the content of microelements Mn, Cu, Zn, Co, Mo, B in soils of different zones of Omsk Irtysh region and plants grown on them are presented. The content of acid-soluble forms of Mn, Cu, Zn, Co, determined in 5M HNO3, in chernozem and solonets soils of the forest-steppe and steppe approaches the background total content in the chernozems of the south of Western Siberia. It depends on the content of sludge fractions, physical clay, the value of the cation exchange capacity. On the soils of the southern taiga, plants are deficient in mobile B, Mo, Co, Cu. In the chernozem and solonets soils of the forest-steppe and steppe zones, the mobility of the Cu, Zn, Co compounds is low (0.5-1.2% of acid-soluble forms), Mn (1.8-3.3%), B and Mo (5-13% ) is higher. The content in mobile zinc soils is estimated as low, Mn, Cu, Co as low and medium, Mo - medium and high, B - high. The level of trace elements in natural and cultivated plants is higher than in the southern taiga, however, a low content of Cu, Co, and sometimes Zn is often observed. In solonetzes and saline soils, excessive concentrations of mobile B are contained, which contributes to an increase in the entry of the element into food chains.

Copper Adsorption by Chernozem Soils and Parent Rocks in Southern Russia

Laboratory data in Cu2+ adsorption by chernozems and parent rocks in Rostov region show that adsorption isotherms can be approximated by the Langmuir equation, whose parameters (Kl and C∞) were calculated for all of the samples. The values of C∞ show a strong negative correlation with the values of cationexchange capacity (CEC) (r =–0.88 at Р = 0.95), and Kl is correlated with the content of physical clay (particles <0.01 mm) (r = 0.78) and with clay (particles <0.001 mm) content in ordinary chernozem and southern chernozems of various particle size distribution (r = 0.80). Even stronger correlations were detected between these parameters in southern chernozems (r = 0.89 for the physical clay (PC) and r = 0.91 for the silt). However, none of the samples displays a significant correlation of C∞ and Kl with the contents of physical clay and silt. This led us to conclude that the composition of the samples, for example, their organic matter, can affect Cu2+ adsorption by the soils and parent rocks. Acidification mechanisms of the equilibrium solutions during the Cu2+ adsorption by soils are discussed, as also are the reasons for the absence of balance between Cu2+ adsorbed by soils and exchangeable cations transferred into solution. Analysis of the fine structures of the XANES and EXAFS spectra suggests that Cu2+ can form coordinated chelate complex compounds with humic acids (HA) of soils and can substitute Al3+ at octahedral sites when interacting with clay minerals in soils.

Postpyrogenic Polycyclic Soils in the Forests of Yakutia and Transbaikal region

Periodical forest fires are typical natural events under the environmental and climatic conditions of central and southern Yakutia and Transbaikal region of Russia. Strong surface fires activate exogenous geomorphological processes. As a result, soils with polycyclic profiles are developed in the trans-accumulative landscape positions. These soils are specified by the presence of two–three buried humus horizons with abundant charcoal under the modern humus horizon. This indicates that these soils have been subjected to two–three cycles of zonal pedogenesis during their development. The buried pyrogenic humus horizons accumulate are enriched in humus; nitrogen; total and oxalate-extractable iron; exchangeable bases (Са+2 and Mg+2); and the fractions of coarse silt, physical clay (<0.01 mm), and clay (<0.001 mm) particles in comparison with the neighboring mineral horizons of the soil profile. The humus of buried pyrogenic horizons is characterized by the increased content of humic acids, particularly, those bound with mobile sesquioxides (HA-1) and calcium (HA-2) and by certain changes in the type of humus.

Modelling Thermal Diffusivity of Differently Textured Soils

A series of models has been proposed for estimating thermal diffusivity of soils at different water contents. Models have been trained on 49 soil samples with the texture range from sands to silty clays. The bulk density of the studied soils varied from 0.86 to 1.82 g/cm3; the organic carbon was between 0.05 and 6.49%; the physical clay ranged from 1 to 76%. The thermal diffusivity of undisturbed soil cores measured by the unsteady-state method varied from 0.78×10–7 m2/s for silty clay at the water content of 0.142 cm3/cm3 to 10.09 × 10–7 m2/s for sand at the water content of 0.138 cm3/cm3. Each experimental curve was described by the four-parameter function proposed earlier. Pedotransfer functions were then developed to estimate the parameters of the thermal diffusivity vs. water content function from data on soil texture, bulk density, and organic carbon. Models were tested on 32 samples not included in the training set. The root mean square errors of the best-performing models were 17–38%. The models using texture data performed better than the model using only data on soil bulk density and organic carbon.

Diagnostics of Compaction of Arable Soils in the Transvolga Region in Saratov Oblast

The evidence and factors of the formation of compact horizons in haplic chernozems are discussed. They include a complicated combination of agronomical consolidation, modern solonetzization, and residual alkalinity. It is shown that the combination of physicomechanical and chemical properties (high content of physical clay and clay fraction, low portion of aggregate openness and high interaggregate porosity, the presence of exchangeable sodium in the soil adsorbing complex, alkaline reaction (pH 8.3), mobility of the clay-humus fraction, etc.) favor the formation of overcompacted plow and subplow horizons and their dynamic stability independently of regular mechanical cultivation.

PHYSICAL AND CHEMICAL PROPERTIES OF SOIL IN FRUIT GROWING AREA TOPOLA (SERBIA)

The aim of the investigation was to assess the level of soil fertility and repair measures in order to enhance the productivity of fruit production in a traditional fruit growing area. (Municipality of Topola, Serbia). The following tests were performed: mechanical composition, physical and chemical properties of soil, total adsorbed base cation, capacity of adsorbed base cation, degree of base saturation, different types of soil acidity, contents of carbon, humus, total nitrogen, easily accessible forms of P2O5 and K2O. Results obtained have shown that soils from all studied sites are of “heavy” mechanical texture with 75,40-84,90% of physical clay. High capacity of cation adsorption, low to medium hydrolytic acidity and high to almost complete saturation of adsorbed bases, has been measured. In compliance with previous analyses, it has been assessed that soils are neutral and of low acid chemical reaction, with low carbon and medium humus content and total nitrogen. Easily accessible content of P2O5 and K2O varies depending on the food quantity on individual parcels with low to medium accessibility to parcels with no fruit plantations. Based on the parameters analysed, the tested soils demand repair of mechanical properties, which will facilitate greater nutrient uptake.

Властивості алювіальних наносів річок Верхньодністровської алювіальної рівнини

Alluvial soil formation is a dynamic process, the main prerequisite of which is the regular, periodic flooding of the river floodplain with flood waters, which are enriched with multidispersed organic and mineral particles. During the last century, about 80 % of territory of the Upper-Dniester alluvial plain was transformed by means of hydrotechnical construction: waterproof dams and drainage channels have broken the wide river floodplains into isolated fragments, making impossible the free flow of flood waters, enriched with silt. The results of the study of stratification patterns of the river silt in the riverbed floodplain, depending on the flow velocity, granulometric composition, physical and chemical properties, given its role in the floodplain soil formation are given. The granulometric composition of the Dniester River silt changes downstream from the sandy to the heavy-loamy; In the floodplains of the Stryj and Svicha rivers medium- and heavy-loamy deposits are postponed, respectively. In the upper part of the Upper- Dniester alluvial plain (Chaikovichi 1, 2) accumulates a silt with predominance of the medium and fine sand fraction, which forms a good filtration ability of soils, whereas downstream the physical clay content increases (up to 47.2 %), which makes the river silt an important source of mineral nutrition of plants. The domination (over 40 %)in silt granulometric composition the rough dust fraction (Ustia 1, Zalisky 1) contributes to the improvement of the water-physical properties of alluvial soils and provides optimal conditions for the biota functioning. For the investigated river alluviums an alkaline reaction of the extract (pH (H2O) = 7,44–8,03) and low content of humus (0,54–3,80 %) are characteristic. The amount of nitrogen in the silt varies within 1,47–18,20 mg/100 g of soil. The river alluviums of the Upper-Dniester alluvial plain are an active factor in floodplain soil formation, since it optimizes the water-physical and physical-chemical properties of alluvial soils. But the influence area of silt on the soilsis sharply reduced and is limited only to the space in front of the dams. In the soils outside the dam, to which no fresh alluvial material comes, the hydrological regime is rebuilt and properties change substantially, up to the loss of their typological alluvial features. Key words: river alluviums, silt, floodplain, the Upper-Dniester alluvial plain, alluvial soils, hydrotechnical fragmentation.

AGROPHYSICАL STATE OF SODDY SOILS OF THE TRANSCARPATHIAN LOWLAND

Problem Statement and Purpose. Soddy soils are the basis of agricultural land of the Transcarpathian lowland. They have been long and extensively used mainly for arable land, are intensive anthropogenic pressure leading to physical degradation. However, there is not much data on soddy soils of the Transcarpathian lowland in the scientific literature. Therefore, the studies of agrophysical state of arable soddy soil, degradation processes development, methods for the optimization of the physical properties are quite important.The purpose of the research is to characterize the current agrophysical state of arable soils of the Transcarpathian lowland. The object of research – arable soddy soil of the Transcarpathian lowland. Subject of research – morphological characteristics, granulometric, microaggregate, structural-aggregate composition of soil, physical degradation processes.Data &amp; Methods. In writing the article, we used materials of own field and laboratory studies. Commonly used methods of soil study have been applied (comparative geographical, comparative profile, analytical methods). Evaluation of soil agrophysical state was performed by calculating the relevant factors and indices. Physical degradation of soils was estimated by the methods adopted in Ukraine.Results. Soddy soils (Albeluvisols Gleyic (ABgl) are typical in the Transcarpathian lowland. Arable soil horizon is gray, light gray with a distinct brown shade (10YR6/2-10YR6/3 based on the Munsell color system). It is very dense, coated with crust and is broken down by wide cracks up to 15 mm in size, it is solid with the lumpy structure.The content of physical clay (particles smaller than 0.01 mm in diameter) in the arable horizon Неgl of highly loamy soddy soils is 49.08%, mildly loamy – 57.72%, medium loamy – 65.24-67.24%. High concentrations of dust in the soil, in particular of medium dust (particle size – 0.01-0.005 mm) results in connectivity in the dry state, viscosity and stickiness in humid state, low permeability. These phenomena are accompanied by deterioration in the structures, creation of blocks, formation of a crust on the surface, cracking.Among microaggregates, the arable horizon is dominated by the 0.25-0.05 mm and 0.05-0.01 mm fractions, the content of which is 18.76-26.36% and 34.00-63.00%. The content of sludge in the horizon Неglор. varies within 1.60-3.84%. Soddy soils are characterized by high potential ability to structure formation.Content of air-dry agronomically valuable 0.25-10.0 mm aggregates in the arable soil horizon is 16.34-29.63%. According to the accepted estimates, the structural and physical state of the soil is characterized as unsatisfactory. The degree of degradation of structural-aggregate composition of the soddy arable soil is characterized as too high (crisis).By the density of the arable layer structure (1.34-1.57 g / cm3) and the total porosity (47.7-39.5%), the soils have suffered medium, high and very high (crisis) physical degradation.Physical degradation of soddy soil is purely of anthropogenic origin. Optimization of the agrophysical state of the soddy soil of the Transcarpathian lowland is based on decrease in the the specific pressure on the soil and minimization of the use of heavy machinery, use of organic fertilizers, green manure crops sowing, crop, soils liming.

Indicative capacity of NDVI in predictive mapping of the properties of plow horizons of soils on slopes in the south of Western Siberia

The informativeness of NDVI for predictive mapping of the physical and chemical properties of plow horizons of soils on different slope positions within the first (280–310 m a.s.l.) and second (240–280 m a.s.l.) altitudinal steps has been examined. This index is uninformative for mapping soil properties in small hollows, whose factual width is less than the Landsat image resolution (30 m). In regression models, NDVI index explains 52% of variance in the content of humus; 35 and 24% of variance in the contents of total and nitrate nitrogen; 19 and 29% of variance in the contents of total and available phosphorus; 25 and 50% of variance in the contents of exchangeable calcium and manganese; and 30 and 29% of variance in the contents of fine silt and soil water, respectively. On the basis of the models obtained, prognostic maps of the soil properties have been developed. Spatial distribution patterns of NDVI calculated from Landsat 8 images (30-m resolution) serve as the cartographic base and the main indicator of the soil properties. The NDVI values and the contents of humus, physical clay (<0.01 mm) and fine silt particles, total and nitrate nitrogen, total phosphorus, and exchangeable calcium and manganese in the soils of the first altitudinal step are higher than those in the soils of the second altitudinal step. An opposite tendency has been found for the available phosphorus content: in the soils of the second altitudinal step and the hollow, its content is higher than that in the soils of the first altitudinal step by 1.8 and 2.4 times, respectively. Differences in the pH of soil water suspensions, easily available phosphorus, and clay in the soils of the compared topographic positions (first and second altitudinal steps and the hollow) are statistically unreliable.

Influence of transport infrastructure on water permeability of soils of Western Siberia

Correctly designed transport infrastructure should support the current economic relations. It should provide a reserve for development of economy of the region in the future. In Western Siberia, new highways are actively being built and major repairs of the operating roads are being conducted. Local materials are often used in the roadbed construction. In the Tyumen region, it is usually sandy silt and clayey sand. The soil has unfavourable physico-mechanical properties. The soil is prone to water and wind erosion. This type of ground gets on the adjacent to the road territory. Studies on the influence of highways on soil permeability were carried out on the basis of the federal highway Tyumen-Omsk. Three types of soils, which are actively used in the agricultural sector, were considered. It is found that the content of particles with the size less than 0.01 mm reaches 32% in the soil used in road construction. It is noted that a part of these particles accumulates on the adjacent to the road territory since it is being washed out from roadbed. The content of physical clay (<0.01 mm) in soils increases by 34-62% relative to the initial values. The width of active accumulation of silt particles reaches 15-20 m along the roads. The soils at the distance up to 10 m from the highway are almost impermeable to water. Absence of a natural hydrological drain, results in the territory bogging. An inverse close correlation was established between the content of physical clay (<0.01 mm) and water permeability (r = 0.90).

Effect of rainfall intensity and slope steepness on the development of soil erosion in the Southern Cis-Ural region (A model experiment)

The effect of rainfall intensity on the erosion of residual calcareous agrogray soils and clay-illuvial agrochernozems in the Southern Cis-Ural region on slopes of different inclination and vegetation type has been studied by simulating with a small-size sprinkler. It has been shown that soil loss linearly depends on rainfall intensity (2, 4, and 6 mm/min) and slope inclination (3° and 7°). When the rainfall intensity and duration, and the slope inclination increase, soil loss by erosion from agrogray soils increases higher than from agrochernozems. On the plowland with a slope of 3°, runoff begins 12, 10, and 5 min, on the average, after the beginning of rains at these intensities. When the slope increases to 7°, runoff begins earlier by 7, 6, and 4 min, respectively. After the beginning of runoff and with its increase by 1 mm, the soil loss from slopes of 3° and 7° reaches 4.2 and 25.7 t/ha on agrogray soils and 1.4 and 4.7 t/ha on agrochernozems, respectively. Fallow soils have higher erosion resistance, and the soil loss little depends on the slope gradient: it gradually increases to 0.3–1.0 t/ha per 1 mm of runoff with increasing rainfall intensity and duration. The content of physical clay in eroded material is higher than in the original soils. Fine fractions prevail in this material, which increases their humus content. The increase in rainfall intensity and duration to 4 and 6 mm/min results in the entrapment of coarse silt and sand by runoff.