Humus Horizon Research Articles

Magnetic prospecting and rock magnetic study of soils and archaeological objects on the Late Roman time sites near Komariv in Middle Transnistria

The paper presents the outcome of the magnetic survey at the settlement and cemetery of the production center of the 3rd—5th centuries, Komariv (Khotyn district, Chernivtsi region), which is located on the right bank of the Dniester. The settlement has about seventy anomalies that may have an archaeological origin. The archaeological study of individual anomalies has confirmed, as expected, the reliability of geophysical interpretation of thermal structures (kilns, furnaces) and living and production dugouts deepened into the loess parent rock. Magnetic imaging at the cemetery showed about eight tens of local anomalies with an intensity of 1.5—4.5 nT. Excavations of some anomalies revealed the Early Iron Age dugout and two Late Roman graves. However, the other two excavated graves did not cause disturbance of magnetic field. Laboratory measurements of magnetic susceptibility, natural remanent magnetization and other concentration-dependent and grain-size-dependent parameters of the ferromagnetic phase, as well as magnetic mineralogy examination have shown that grave pits, which appeared on a magnetic map, are refilled almost exclusively with humus soil material. Magnetic modeling proved graves can create measured anomalies if their magnetization is equal to the magnetization of the humus horizon of the soil. Thus, these grave pits were left open and gradually refilled with moist soil material. In particular, conditions have been created for the formation of detrital remanence. When restoring the spatial structure of Komariv sites based on magnetic prospecting results, it is necessary to take into account probable multilayered structure of monuments, geomorphological features of the area, which can be misinterpreted as archeological objects, and the fact that important examples of ancient architecture constructed of non-magnetic materials and grave pits refilled immediately after digging will be absent on magnetic maps.

Microaggregate Composition as a Factor of Variability in the Physical Properties of Gray Forest Soils in Western Siberia

The aim of the study was to study the variability of the microaggregate composition of the soil profile of virgin gray forest soils in the western part of the West Siberian Lowland. 330 soil sections were studied, covering all subtypes of gray forest soils. Empirical data were processed using mathematical methods of variation statistics. The results of the research showed that the humus horizon of light gray forest soils is characterized by good water resistance of microaggregates - the dispersity factor on average for the sample is 14.6%, the variation is small (Cv = 19%). Gray forest soils in the humus horizon have, on average, a dispersity factor of 12.2%. This subtype, in comparison with light gray soils, has a higher variability of the dispersity factor (Cv = 24%), which is due to the variety of combinations of soil formation factors, mainly relief and vegetation. The dispersity factor of the humus horizon of dark gray forest soils averages 7.9% for the sample, which is typical for medium structured soils; the variation is estimated as small (Cv = 18%). The microaggregate composition of gray forest soils is characterized as satisfactory throughout the entire soil profile, which makes it possible to improve structure formation during agricultural development and maintain the optimal structural-aggregate composition for a long time. The results obtained can be used in the development of an adaptive-landscape system of agriculture.

The influence of agroforestry on Chernozems: a case study of the Central Russian Upland

Agroforestry is an essential tool for improving soil fertility and sustainable land use. We aimed to reveal the role of the old-growth shelterbelt in changing the basic Chernozem properties under the shelterbelt and at 10, 30, and 60 m distance from its edges (the south of the Central Russian Upland, Belgorod region). Our database includes organic carbon content, storage, and group composition, total nitrogen, exchangeable magnesium and calcium, the soil - water extract composition, and pH from different soil layers up to 3m. We detected the increase in humus horizon thickness, soil organic carbon content and storage, total nitrogen, exchangeable magnesium, acidification, and lowering the effervescence line in shelterbelt soil in comparison to arable ones. Agroforestry leads to the soil transformation - the shelterbelt soils differ from arable at subtype taxonomic level, and the influence of shelterbelts on adjacent arable soils can be traced up to 60 meters distant.

Экологическая оценка качественных характеристик газонных травостоев на урбанизированных дерново-подзолистых почвах в условиях экологического стационара РГАУ-МСХА им. К.А. Тимирязева

The article presents the results of research on the analysis of the influence of complex mineral fertilizers of different composition and structure-forming material perlite on the quality indicators of seeded lawns grown on urbanized sod-podzolic soils under the conditions of the Ecological Station of the Russian State Agrarian University named after K.A. Timiryazev. The influence of complex mineral fertilizers of different composition and perlite on the resistance of the sown lawns to unfavorable agro-ecological conditions has been analyzed. Materials and methods. The fine-grained field experiment was carried out on the territory of the ecological stationary of the K.A. Timiryazev Russian Academy of Agriculture in Moscow during 2019-2020 together with the strategic partner: the company LLC "EuroChem Trading RUS" on the urbanized agrodeposol soil of medium loamy granulometric composition with buried humus horizon. The multifactorial study was carried out on seeded lawn grasses grown with the use of various types of complex fertilizers, as well as structure-forming component - perlite. Keywords: LAWNS, URBAN SOILS, MINERAL FERTILIZERS, LANDSCAPING, GRASS BIOMASS, PERLITE

Морфологические, диагностические признаки и агрофизические свойства орошаемых лугово-сероземных почв в аридных земельно-климатических условиях (Азербайджан)

The article presents morphological, diagnostic features and agrophysical properties of meadow-sierozem soils irrigated in arid soil-climatic conditions of Azerbaijan. The research was carried out on lands in the territory of the village of Malbinasi, Yevlakh district, in the Arzu farm. The thickness of the humus horizon of irrigated meadow-sierozem soils of the object of study is 55-65 cm. Hardening is most often observed in the deep layers. Due to siltation, a cloddy-granular structure was formed in the subsurface horizon. With increasing depth, a sharp increase in soil density is observed.

Recognition of the Bare Soil Using Deep Machine Learning Methods to Create Maps of Arable Soil Degradation Based on the Analysis of Multi-Temporal Remote Sensing Data

The detection of degraded soil distribution areas is an urgent task. It is difficult and very time consuming to solve this problem using ground methods. The modeling of degradation processes based on digital elevation models makes it possible to construct maps of potential degradation, which may differ from the actual spatial distribution of degradation. The use of remote sensing data (RSD) for soil degradation detection is very widespread. Most often, vegetation indices (indicative botany) have been used for this purpose. In this paper, we propose a method for constructing soil maps based on a multi-temporal analysis of the bare soil surface (BSS). It is an alternative method to the use of vegetation indices. The detection of the bare soil surface was carried out using the spectral neighborhood of the soil line (SNSL) technology. For the automatic recognition of BSS on each RSD image, computer vision based on deep machine learning (neural networks) was used. A dataset of 244 BSS distribution masks on 244 Landsat 4, 5, 7, and 8 scenes over 37 years was developed. Half of the dataset was used as a training sample (Landsat path/row 173/028). The other half was used as a test sample (Landsat path/row 174/027). Binary masks were sufficient for recognition. For each RSD pixel, value “1” was set when determining the BSS. In the absence of BSS, value “0” was set. The accuracy of the machine prediction of the presence of BSS was 75%. The detection of degradation was based on the average long-term spectral characteristics of the RED and NIR bands. The coefficient Cmean, which is the distance of the point with the average long-term values of RED and NIR from the origin of the spectral plane RED/NIR, was calculated as an integral characteristic of the mean long-term values. Higher long-term average values of spectral brightness served as indicators of the spread of soil degradation. To test the method of constructing soil degradation maps based on deep machine learning, an acceptance sample of 133 Landsat scenes of path/row 173/026 was used. On the territory of the acceptance sample, ground verifications of the maps of the coefficient Cmean were carried out. Ground verification showed that the values of this coefficient make it possible to estimate the content of organic matter in the plow horizon (R2 = 0.841) and the thickness of the humus horizon (R2 = 0.8599). In total, 80 soil pits were analyzed on an area of 649 ha on eight agricultural fields. Type I error (false positive) of degradation detection was 17.5%, and type II error (false negative) was 2.5%. During the determination of the presence of degradation by ground methods, 90% of the ground data coincided with the detection of degradation from RSD. Thus, the quality of machine learning for BSS recognition is sufficient for the construction of soil degradation maps. The SNSL technology allows us to create maps of soil degradation based on the long-term average spectral characteristics of the BSS.

Assessment of risk to health of the population from soil pollution by heavy metals: theoretical- methodological and ecological aspects


 
 
 
 Existing methodological approaches to assessing the risk to public health from the effects of heavy metal pollution are highlighted. This article considers the influence of emissions from motor transport and industrial enterprises on the level of soil contamination by movable forms of heavy metals in different functional zones of the Odessa city. The degree of technogenic and chemical pollution of urban soils is determined by ecological indicators: concentration coefficient (Kc), hazard coefficient (Kn) and total pollution indicator (Zc). It is established that the indicators of the content of heavy metals in the humus horizons of the soils of Odessa city have a high variability and depend on the degree of industrial and transport impact. It was found that only the soils of the Botanical Garden have an optimal content of heavy metals. It is established that the soils are the most polluted by emissions from road transport in terms of lead (18 TVL), zinc (23 TVL) and cadmium (15 TVL). Accumulation of heavy metals was found in all studied soils of the city. The ecological condition of soils varies from optimal (park zone) to unsatisfactory condition (zone of joint influence of motor transport and industrial enterprises). In terms of total pollution, soils within the impact of road transport and industrial enterprises have a very high (extremely dangerous) level of pollution. The highest values of the total indicator of soil pollution were determined within the impact of road transport (Zc = 758.72) and the combined impact of industrial enterprises and road transport (Zc = 921.6). For the first time, a method was used to assess the risk to the health of the population of the Odessa city from the effects of soil contamination with heavy metals according to the probit regression model. It was determined that the study area of the city mainly has a high and dangerous risk to public health. The conducted researches allowed us to reveal the level of toxicity of the city soils and the level of danger to the health of the population, which will contribute to the implementation of appropriate measures to reduce pollution of the urban environment. The methodology for assessing the health risk from urban soil pollution by heavy metals is a promising approach to quality control of the system «environment – human health» and requires further research.
 
 
 

Post-Fire Habitat Heterogeneity Leads to Black Spruce–Kalmia L. Shrub Savannah Alternate State

Many nutrient-poor coarse-textured Kalmia L.–black spruce forest sites in eastern Canada turn to ericaceous heath dominated by Kalmia angustifolia L. after clearcutting and fire. While the mechanisms of post-fire forest and heath formation have been well documented, the origin of shrub savanna vegetation has received limited attention. This study demonstrates the significance of post-fire island regeneration of black spruce in Kalmia heath to the origin of shrub savannah alternate state. The study was conducted in Three Brooks, 10 km west of Grand Falls-Windsor, Newfoundland (48°51′ N; 55°37′ E). Black spruce forest in the site was clearcut, then a wildfire burned the area, and the site was subsequently planted with black spruce. Plant species cover, black spruce growth (stem density, stem height, basal diameter, and yearly volume increment), and foliar nutrients of planted spruce and soil properties (pH, humus and Ae horizon depth, and nutrients) in tree islands were compared with adjacent Kalmia heath. Black spruce islands had significantly lower cover of Kalmia and higher stem density of black spruce compared to Kalmia heath (7100 stems/ha in islands vs. 1920 stems/ha in heath). Height, basal diameter, and yearly volume increment of black spruce were more than three times higher in spruce islands than in Kalmia heath. Foliar nutrients of black spruce growing in Kalmia heath had significantly lower N and Mg (33 and 38%, respectively) but had significantly higher Mn and Zn (46 and 33%, respectively) than in black spruce islands. Black spruce growth inhibition in Kalmia heath is attributed to soil nutrient imbalance due to Kalmia evidenced by reduced concentrations of N and Mg and increased concentrations of Al, Fe, and other inorganic ions in the foliage. These results suggest that post-fire black spruce islands in severely burned patches provide “safe sites” for spruce regeneration, whereas Kalmia heath developing in non-severe burn area inhibits spruce regeneration and creates shrub savannah community as an alternate vegetation state.

Loess soil distribution and properties in Mongolia

Loess and loess-like soil formations are distributed in 3 regions across Mongolia. The lower part of the Orkhon and Selenge river basin in North Mongolia is the main loess area and another two are located in east Mongolia, in the Onon and Ulz river basins and the Khalka Gol river area. Loess-like soil covers a total of 109,000 sq.km or 6.95 per cent of the territory of the country. Loess soil properties have been studied on the basis of 8 sections and 83 samples. Fine sand fraction is predominant in the loess granulometric composition and its mean value is 51.3 per cent, and silt content mean value is about 34.9 per cent. A typical loess is a non-stony silt or fine sand, but there are also gravel loess. The average stone gravel content in the loess sediments is 8.1 per cent, sandy loess doesn’t contain any stone, but coarse fragment is high (20.5 per cent) in gravel loess. There is higher sand content (57.0 per cent) in gravel loess as compared to sandy loess (47.4 per cent). Mongolian loess soil average calcium carbonate content is 2.9 per cent, and Organic Matter (0.93 per cent) is higher than Chinese loess (0.41 per cent). Using 14C isotope data analysis and sediment properties we have tried to define the loess stratigraphy. Lower base section of fine sand silty loess sediments or about 1-3 meter thick layers were mostly formed during the mid-Holocene (7.5-3.0 ka) period. Upper parts of silty loess or 1.0-0.7 meter top layers were accumulated in the late Holocene (3ka BP to present) period. Kastanozem topsoil humus horizon (15-30 cm) formation starts at 1.5-1.0 ka BP. Mid-Holocene period probably witnessed the most active loess accumulation with a warm and dry windy condition prevailing. Sandy loess with a thickness of 1-2 meters predominate in Mongolia, and in some places loess thickness reaches up to 20-30 meters.

Humus horizon development during natural forest succession process in the Polish Carpathians

As a result of socio-economic changes and land abandonment, the main ecological driver of the Carpathian landscape is the progression of the natural forest succession process. Thus, aspects of this process have become worthy of attention, especially in the context of carbon sequestration and the management of protected areas. Soil processes, especially within the topsoil, are some of the most susceptible to change, due to the accumulation of organic matter during such land-use transformations. The purposes of this study were to investigate the differences in topsoil development using the A Horizon Development Index (ADI) and to study the composition of humic substances and advanced organic matter humification in different land-use areas in selected Carpathian national parks, i.e. Bieszczady, Magura and Pieniny National Parks in southern Poland. Additionally, a goal of this study was to compare the ADI and the spectroscopic coefficients of humic substances as indicators of the degree of humus horizon shaping as well as advanced organic matter humification. In total, ten transects were selected, each consisting of three different land-use areas: semi-natural meadow, successional forest and old-growth forest. Soil colour was determined in fresh and air-dried samples using the Munsell colour chart. In air-dried soil samples pH, soil texture, total organic carbon and total nitrogen were measured. Humic substances were extracted and further characterized by UV-VIS spectroscopy. The ADI confirmed the influence of natural forest succession on soil colour darkening and the development of the uppermost soil layer. Spectroscopic analyses of humic substances showed two different patterns depending on soil depth. In the 0–10 cm layer, natural forest succession reduced the rate of the humification process and decreased the degree of maturity of fulvic acids; in the 10–20 cm layer, it led to an increase in the rate of the humification process and a decrease in the content of humic and fulvic acids at the beginning of the transformation. The comparison of two different indicators of soil development — the ADI and the spectroscopic coefficients of humic substances (Q4/6, Q2/4, Q2/3, Δ log K) — indicated that these indexes are based on different features of soil and cannot be used interchangeably.

Organic Matter in Riverbank Sediments and Fluvisols from the Flood Zones of Lower Vistula River

The research objective of this study was to determine whether and to what extent the form of use of Fluvisols (arable soil and grassland) of a Lower Vistula floodplain valley (Fordonska Valley, Poland) determined their relative organic matter properties, as compared with nearby riverbank sediments. Riverbank sediments were sampled from a depth of 0–20 cm, and soil samples from 0 to30 cm, all in three replicates. Basic physico-chemical soil properties were determined: texture, pH, and the contents of total organic carbon (TOC), total nitrogen (TN), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Humic acids (HAs) were extracted by the Schnitzer method and analysed to assess their spectrometric parameters in the UV–VIS range and hydrophilic and hydrophobic properties. Riverbank sediment samples contained significantly lower TOC and TN contents than Fluvisols, regardless of land-use type. The TOC, TN, DOC and DON contents and properties of humic acids in the Fluvisol surface layer depended on land-use type, because the arable soils had significantly lower TOC, TN, DOC and DON contents than the grasslands, despite having a similar grain size (texture). Based on the A2/4, A2/6, A4/6 ratios, it was found that HA molecules isolated from the humus horizon of arable soils had a higher degree of maturity than HAs isolated from grassland soil samples. The spectrometric properties of humic acids isolated from riverbank sediments showed a higher degree of maturity than those from Fluvisols. This research showed that the properties of humic acids in Fluvisols are determined by the quantity and quality of organic matter transported in suspended matter that accumulates annually in flood valleys during flood events. The current land-use type of Fluvisols significantly influenced the properties of organic matter, and thus of humic acids. Therefore, these properties can be used to evaluate the transformation of organic matter that occurs in Fluvisols depending on the type of use.

The Effect of Kerosene Pollution on the Cellulolytic Activity of Albic Retisols and Arenosols (Aridic): A Laboratory Experiment.

The results of a laboratory experiment modeling the effect of kerosene contamination on the cellulolytic activity of microbiocenosis of the Albic Retisol (Kaluga oblast, Russia) and Arenosol (Kyzylorda oblast, Republic of Kazakhstan) humus horizons are described. Cellulolytic activity is assessed according to the rate of weight loss in linen cloth fragments during the incubation for 0–3, 3–7, and 7–13 months. The intensity of cellulolytic activity in the unpolluted Albic Retisol is higher as compared with the Arenosol, which is determined by low acidity and an elevated content of organic matter and nutrients. The soil pollution with kerosene to 10 g/kg causes a reversible change in cellulolytic activity of both Albic Retisol and Arenosol (Aridic). A high load of kerosene (≥25 g/kg) inhibits cellulolytic activity in both soils over 13 months of observation.Supplementary InformationThe online version contains supplementary material available at 10.1134/S1064229322020119.Fig. S1. Cellulolytic activity of soils in a laboratory experiment: (a) initial state of linen tissue (test object) and (b) linen tissue after three months of incubation. Table S1. Properties of soil humus horizons.Table S2. Initial water content in the studied soil samples with due account for the added kerosene.Table S3. Cellulolytic activity in soils grouped according to kerosene load (rate of mass loss, mg/g soil per day.Table S4. Significance of differences between cellulolytic activities of contaminated soil samples relative control samples according to the Mann–Whitney U-test. Table S5. Kerosene content in the studied soil samples at the end of the experiment, % of the initial content.

Soils with the Second Humus Horizon, Paleochernozems, and the History of Pedogenesis at the Border between Forest and Steppe Areas

Soils with the Second Humus Horizon, Paleochernozems, and the History of Pedogenesis at the Border between Forest and Steppe Areas

Ecological Assessment of Disturbances in the Landscape Structure of Alluvial Soils of Floodplains Under Technogenesis Influences

The article considers the problem of disturbances in the landscape structure when extracting constructional sand causes the formation of a technogenic relief. The objective of this study was to determine the change in the main fertility indicators for alluvial turf and meadow soils disturbed by open-pit mining and building communications. The study included tasks stated below. The research tasks included identifying the quantitative changes in the composition and properties of alluvial soils disturbed by construction sand extraction. Determination of the change in the organic matter content of the upper layer in the artificial soil-like formations (technozems) in comparison with undisturbed soils. Specifying the nature of changes in the texture of the humus horizon of donor soils and technozems bulk layers. Determination of the change in the pH of the aqueous extract, and the content of the accessible forms of K2O and P2O5 in the soils disturbed by mining. The objects of the study were: plots of agricultural land with soil samples of alluvial turf and alluvial meadow soils, sampled at a depth of 0-20 cm. In the floodplain zone, the research was conducted on soils with a disturbance within the upper 50 cm thickness on alluvial turf soil. Technozem, an artificial soil-like structure consisting of one bulk layer of technogenic soil, was studied in the central floodplain. The studies found that open-pit mining has an impact on the composition and properties of alluvial soils. Disturbances in the landscape structure at open-pit mining cause significant destruction of a fertile layer as the soil texture changes. There is also a loss of organic matter in the disturbed soils depending on the degree of manifestation of anthropogenesis.

Wind resistance of southern carbonate and ordinary сhernozems in agroforest landscapes of the steppe zone of Russia

Relevance. The rate of destruction of chernozems in the steppe zone as a result of deflation is very high. There is a threat of their loss of the humus horizon. To optimize the complex of protective measures, it is necessary to establish the regularities of the formation of wind resistance of these soils.Methods. The seasonal dynamics of the structure of the upper layer (0–5 cm) of chernozems of the steppe zone of the Lower Volga region and the Central Pre-Caucasus in the network of forest belts is studied. The aggregate composition was determined by fractionation of an air dry sample. The wind resistance of the soil was assessed by the total content of particles with a diameter of less than 1 mm.Results. It has been established that the open surface of southern carbonate chernozems is deflationary dangerous at any time of the year. Two spraying peaks were revealed — in early spring and before harvesting grain crops. In the first period, the content of particles with a diameter of less than 1 mm was 33–47%, in the second — 60–61%. Shelter forest belts reduced soil spraying in the zone of effective influence. A change in the internal structure of the deflationally dangerous fraction was detected during the year. The disintegration of large aggregates and an increase in the volume of smaller ones were observed. By the harvesting period, the number of particles with a diameter of 0.5–1.0 mm decreased by 1.7–2.6 times compared to the spring. Number of aggregates with a diameter of 0.1–0.5 mm, most strongly blown by the wind, increased by 1.3–1.8 times. The total dispersion of ordinary chernozem is almost two times lower than that of southern chernozem. However, the amount of particles with a diameter of 0.1–0.5 mm in the deflationary dangerous fraction of southern carbonate chernozem in the spring period is 37%, during the harvesting period — 50–56%. And in ordinary chernozem, already since the spring, there are more than 55% of such particles, in the future their number increases to 60%. As a result, by the harvesting period, the danger of a fraction with a diameter of less than 1 mm becomes the same for both subtypes of chernozems. This requires adjusting the complex of protective measures.

Фосфор коричневих ґрунтів гірських пасовищ Узбекистану

The aim of this work is to assess the content and distribution of phosphorus in the profile of brown soils (Cambisols, Kastanozems, Leptosols) of the mountain pastures of the Republic of Uzbekistan. Soil incisions laid 7 agricultural areas of the country. Field research, sampling and analytical work were performed in 2019–2021. The list of indicators under study includes the degree of soil erodation, the general content of humus, the content of the clay fraction, the general content of phosphorus and the content of the movable phosphorus in the selected clay fraction and in the soil. A detailed division of phosphorus into reserves and their calculation according to the methodology of calculations of reserves of nutrition elements according to N.I. Gorbunov (1978). The studied mountain brown soils are characterized by a loamy granulometric composition, nutty-cloddy structure, a slightly acidic or slightly alkaline reaction. The total humus content in the upper horizon varies from 1.0 to 6.8 %. The proportion of the clay fraction is from 2.9 to 18.3 %. The content of phosphorus in the clay fractions is 2–3 times higher than in the soil as a whole and the maximum is 0.558 %. The phosphorus reserves was allocated – close, immediate and potential. Fluctuations in the content of phosphorus reserves in the humus horizon were revealed: immediate from 6 to 26 %, near - from 7 to 19 %, potential, dominant in the total content of 68 to 80%. In the humus horizon, an insoluble form of phosphorus occurs, which increases the resistance of soils to water erosion due to the formation of water resistance structures. Uneven distribution of phosphorus and its reserves in brown soils on the mountain pastures of Uzbekistan, both in the soil profile and the regions of the country, is stated, which is affected by the relief, exposure of slopes, the features of soil -forming rocks, atmospheric precipitation, hydrothermal conditions, and the period of biological activity of soils. The losses of the near and direct reserves of the humus lead to a decrease in the total content of the phosphorus as a whole.

Agrogenic transformation of texture-differentiated soil profiles in micro-depressions

The aim of the study. Due to the introduction of texture-differentiated soils of micro-depressions in the agricultural use, the aim of the study was to assess the degree of the soil profile transformation resultant from the different duration of agrogenic exposure. Location and time of the study. The study was carried out in July 2019 and 2021 in the flat-micro-depression agricultural landscape in the Kozhevnikovsky district of the Tomsk region, approximately 6 km east of the Bazoy village. Methodology. To study agrogenic transformation of the profile of texture-differentiated soils, soil pits were dug in the 1) undisturbed depression under forest, 2) in the micro-depression where the forest was cleared less than three years prior to the study, and 3) in the depression cleared of forest and used as an arable land for more than five, but less than ten years at the time of the study. For comparison, a pit was also dug in the adjacent area of agricultural landscape (non-depressed). Main results. In the flat-micro-depression agricultural landscape, the most common soil is Luvic Greyzemic Chernozem (Loamic, Aric). The soil in the micro-depression under the forest is represented by Albic Abruptic Luvisol (Loamic, Cutanic, Humic). The soil in the micro-depression with recently cleared forest is attributed to Abruptic Luvisol (Loamic, Aric). The soil in the micro-depression used as arable land for more than five years is classified as Haplic Luvisol (Loamic, Aric, Humic). Conclusion. When relating the horizontation of the texture-differentiated soils in micro-depressions with agrogenic influence duration, it is notable that the dark humus and eluvial horizons first become blended, and then transform into agro-dark humus horizon. At the same time, the taxonomic attribution first changes at the subtype level, and then at the type level, thus increasing the classification diversity of soils on the studied territory.

Morphological Feature and Physicochemical Characteristics of Soils under <i>Festuca</i> spp. Dominant Steppe at High Mountain and Mountain of Khuvsgul, Mongolia

The morphology, physicochemical, humic substances and micromorphological characteristics of four soil profiles of the steppe dominant by Festuca lenensis (F. lenensis) at the high mountain and mountain of Khuvsgul, Mongolia were studied. Soils were classified as Regosols and Leptosols at high mountain steppe, Leptosols and Cambisols at mountain steppe. On a high mountain, the plant root distribution, OC, N and moisture contents were high due to its high precipitation and low temperature. The soils show immature characteristics with low available nutrients, weakly developed crumb structure, many semi- and undecomposed plant residues, and few little organic pigments with few excrements. The humic acids with immature to degraded characteristics indicate that the climatic condition of high mountains inhibits the soil decomposition process. Due to extremely different landform positions, there a sharp difference was observed between studied soils on high mountain steppe. On the summit with a flat position, the soil of TSO1 showed finer soil texture with higher CEC, exchangeable Mg2+ and humification degree of SOM compared with the soil of TSO2, which located on the steep slope. This confirms that the abrupt changes in landform on high mountain strongly affect the properties of topsoil. On the mountain steppe, the soil contains higher exchangeable Na+, exchangeable K+ and water soluble at topsoil; however, the plant root distribution, OC, N and moisture contents were lower than that of high mountain soil. Because of warmer air and soil temperature in comparison with that of high elevation, active turnover in humic horizon and chemical weathering process lead to higher available nutrients in mountain steppe. The degraded to well humified characteristics of humic acid, moderately developed crumb structure, a higher component of little organic pigment and many intact excrements indicate that the soil decomposition process and biological activity were higher than that of the high mountain steppe. Our finding suggests that the climatic condition dependent on altitude and landform position at the high mountain and mountain of Khuvsgul had a large impact and played a key role in the soil properties and characteristics of steppe dominant by F. lenensis.

Degradation of the structure of meadow-chernozem soils in different eco-industrial conditions

The features of the structure of semi-hydromorphic meadow-chernozem soils in the Central Chernozem region (Belgorod oblast) and in the Krasnodar territory are studied. Both regions are characterized by the dominance of chernozem soils, but with different specialization of grain farming. It was identified that the patterns of changes of the waterproofness of the structure vary considerably in the study soils. Ambiguous results of assessing the quality of the arable soils using classifications by different authors were obtained. It is shown that the determination of the degradation degree of arable soils by the absolute values of the structure parameters is incorrect. The structure of arable and fallow soils for each region was compared. The content of agronomically valuable fractions in the arable horizons of cultivated soils and humus horizons of fallow lands shows that there is no degradation of the structure in rice soils, and in meadow-chernozem there is weak degradation in the «plow sole».

Современное использование земель бассейна реки Оса (Верхнее Приангарье)

The territory of the Osa river basin was studied, where under the steppe and forest-steppe vegetation types of soils are common that are not typical for the taiga zone: real chernozems with a relatively thick humus layer, sometimes reaching 45-50 cm, dark humus soils and other types of fertile soils. It has been established that hydrometamorphosed chernozems with a thickness of the humus horizon of more than 1 m are widespread in low relief areas, under conditions of increased moisture. a series of expeditions was carried out to study the soils of natural, arable and fallow lands, as well as pastures. The content of humus and the granulometric composition of soils were determined (types of natural soils: gray typical, hydrometamorphosed chernozem, thin chernozem, typical dark humus; types of agrogenic analogues of natural soils: typical agroabrazem, dark agrozem, typical agrogrey, agroserohumus typical, agrodark humus typical, hydrometamorphosed agrochernozem, typical agrochernozem; more than 30 samples). The influence of these indicators on soil fertility is considered. The change in the nature of land use in the period from 1983 to 2013 has been studied, and possible reasons for these changes. A map of modern land use in 2021 was made. A comparison was made of the nature of modern land use with their use in 1983, 1997, 2005, 2013.