Soil cover patterns in the Dzhida Depression and their representation on the soil map of 1: 500000 scale

A map of the soil cover patterns in the Dzhida Depression (Baikal region) has been compiled on a scale of 1: 500 000. The grouping of the soil cover patterns into larger categories makes it possible to retain the information contained on large-scale soil maps upon their generalization to the small-scale soil map. The latter displays the regularities of soil distribution at the levels of soil types and subtypes. The areas of the major soil groups have been calculated. It is shown that podburs predominate in the northern taiga ecosystems (72%), whereas acid soddy taiga soils (71%) and podburs (22%) predominate in the middle taiga zone. Minor areas in these zones are occupied by podzolic soils (9%) and permafrost-affected taiga gley soils (14%).     

The soil cover pattern in Western Transbaikal region as displayed on a 1: 500 000 scale map

Specific features of the soil cover in the Western Transbaikal region are discussed. The soil cover has been studied during soil survey works on scales of 1: 25000 and 1: 100000 in the Kizhinga district. On this basis, a generalized map of the soil cover patterns has been compiled on a scale of 1: 500 000. Data of the large-and medium-scale soil mapping are not lost upon the generalization procedure due to the reflection of soil combinations on the small-scale map, which makes the latter very informative.     

Soil cover patterns in the Tugnuisk Depression of the Transbaikal region

A map of soil cover patterns in the Tugnuisk Depression of the Transbaikal region has been compiled on a scale of 1:500 000. This map contains information on the distribution of soil complexes and soil combinations and on the genetic and geometric characteristics of soil areas. It is derived from the original large-scale soil maps. The theory of soil cover patterns was used as the basis for cartographic generalization. This made it possible to preserve information on soil types and subtypes identified on the original maps and to show the real distribution pattern for all the components of the soil cover.     

Mycelial fungi in saline soils of the western Transbaikal region

Mycelial fungi in a solonchakous chestnut soil, a sulfate solonchak, and a soda solonchak were studied in the western Lake Baikal basin. The humus content, the degree of salinization, and the composition of salts affected the structure of the micromycete communities. In the chestnut soil, more than half of the species identified were found. The species diversity was higher in the nonsaline and humus horizons. The eolian deposit on the soda solonchak was characterized by the presence of six species of fungi that did not occur in other soil horizons. Their occurrence in the fresh deposit seems to be related to the eolian transfer of fungi with the fine earth from the adjacent areas with the nonsaline soils. The soda solonchak fungi are dominated by the haloalkalitolerant and alkalophilic micromycetes, among which the representatives of the Acremonium (A. antarcticum and A. rutilum) and Verticillum genera and Mycelia sterilia were identified. There was also an alkalophilic ascomycete, which is an indicator of soda salinization??Heleococcum alkalinum. On the whole, the soda solonchak had the lowest number of fungal germs and the lowest species diversity of mycelial fungi among the soils compared.     

Soil cover pattern on the northern macroslope of the Tsagan-Daban Ridge in the Transbaikal region

Regularities of soil distribution in the basin of the Vorovka River on the northern macroslope of the Tsagan-Daban Ridge are discussed, and the grouping of soil cover patterns in this area is suggested. Dissected middle-mountain areas covered by taiga forests are characterized by a combination of predominate soddy podburs with small homogeneous areas of podburs and lithozems. Within the piedmont part of the basin, components of soil combinations are different. The major areas are occupied by sandy soils under dry grassy pine forests; poorly developed soils are formed on recent alluvial and colluvial deposits in the depressions and hollows.     

Mesofauna in soils of the ivolga depression (Western Transbaikal region)

Mesofauna of chestnut, meadow-chestnut, meadow alluvial, clayey mucky-gley swampy alluvial soils, and hydromorphic solonchaks has been studied within the Ivolga depression. Variations in the population density of soil invertebrates (from 29.9 to 284.3 specimens per m²) are controlled by the particular soil ecological conditions. Dominant mesofauna species are morphologically and physiologically adapted for living near the soil surface. About 85–90% of them are allocated to the uppermost 10-cm-thick soil layer. The hydrothermic regime (r = 0.94) and the low bioproductivity of phytocenoses (r = 0.74) are the major factors limiting the mesofauna functioning in soils of the Ivolga depression. The biocenotic similarity of the invertebrate complexes in the chestnut, meadow-chestnut, and solonchak soils and in the alluvial swampy and meadow soils is revealed. The highest diversity of the ecological groups of soil mesofauna is seen in the clayey mucky-gley swampy alluvial soils.     

Digitized version of the state soil map on a scale of 1 : 1 M: Problems and solutions

Problems of the creation of a high-quality digitized version of the State Soil Map (SSM) on a scale of 1 : 1 M for the European part of Russia are discussed. Sheets of the SSM have been compiled for the entire territory of Russia. For the European part of Russia, they have been digitized, and a corresponding geographic information system has been created. At present, the attribute database to the map is being developed. In the course of the digitization of separate sheets of the map and the creation of a general legend, certain drawbacks of the map have been revealed. They are related to the insufficient completeness of information on the genesis of soil-forming rocks shown on different sheets; to the inconsistency in the names of some soils; and to the use of the same conventional signs for describing the soil texture in the upper horizons and in the parent material, which is incorrect in the case of texture-differentiated soils. The reasons for these drawbacks of the original map are explained. It is stressed that the SSM is a highly informative map that has played a crucial role in the development of pedology and soil cartography in Russia. A digitized version of this map makes it possible to introduce certain corrections to the original map sheets. The essence of the first stage of the work on the correction of the SSM in the digitized version and the methods applied for this purpose are characterized. Problems related to the creation of the database for the digitized version of this map are also discussed.     

Humus and humic acids in chernozems of the southeastern Transbaikal region (Chita Oblast)

Humic acids (HAs) in the noncalcareous chernozems developed from the colluvium of argillites and chlorite schist are characterized by a predominance of the first, relatively mobile fraction (HA-1) and a lower content of the second (HA-2) fraction. Modern nondestructive physicochemical methods for studying the chemical structure of HA macromolecules have shown that the Has in the virgin soils have approximately equal portions of aromatic and aliphatic groups. In the plowed soils, the portion of aromatic carbon increases under the impact of the intensive agricultural use of these soils and their susceptibility to wind erosion.     

Experience in digital mapping of soil cover patterns

Methodological problems of large-scale soil mapping with the use of digital mapping technologies are discussed. Two variants of obtaining the maps of soil combinations for a test polygon (30 km²) in the area of soddy-podzolic soils with 996 studied soil pits are described. In the first variant, the initial state of soils at studied points was characterized by the taxonomic name of the soil (at the level of soil subtypes); the probability of occurrence of different subtypes within operation cells of the digital map was estimated, and the most probable soil subtypes were assigned to them. This approach was tested for the first time. In the second variant, the initial state of soils at studied points was described with the help of the grades of ecologically meaningful features of soil morphology; the degree of soil gleying and the degree of soil erosion or aggradation were indicated. The integral digital map represented the areas of different agroecological groups of soil combinations. The maps obtained with the help of these two approaches show a satisfactory agreement with the maps of soil cover patterns compiled by traditional methods earlier.     

Soil cover patterns in the southern part of the Sikhote Alin Range (using the example of the Ussuri Nature Reserve)

The soil cover of the Ussuri Nature Reserve in the southern part of the Sikhote Alin Range is described. The geographic regularities of the soil distribution within the territory of the reserve are analyzed, and the major types of soil cover patterns at different levels of their organization are characterized.     

Estimation of the areas of salt-affected soils in the European part of Russia on the basis of a digital map of soil salinization on a scale of 1 : 2.5 M

A digital version of the map of salt-affected soils on a scale of 1 : 2.5 M has been used to calculate the areas of these soils in the four federal okrugs (the Southern, Central, Volga, and Northwestern) of European Russia. The total area of soils with soluble salts in the upper meter reaches 23.3 million ha. More than half of them are solonchakous soils (with soluble salts in the layer deeper than 30 cm), and about 25% are saline from the surface. Soils of sulfate and chloride-sulfate salinization predominate (>50% of the area of salt-affected soils). Alkaline soda-saline soils and soils with the participation of soda comprise about 6%. We consider this value to be underestimated and requiring refinement, because soils of solonetzic complexes with neutral salts in the upper horizons may also contain soda in the solonetzic and subsolonetzic horizons, which was not always taken into consideration upon assessing the chemical composition of the salts. Solonetzes proper and solonetzic soils predominate among the salt-affected soils in the European part of Russia. The area of solonetzes is up to 9.4 million ha. The area of solonetzic soils (including solonetzic soils with salts in the layers of 0–100 and/or 100–200 cm) is 15.5 million ha. The highest percentage (32.2%) of salt-affected soils is in the Southern federal okrug.     

Mercury in humus horizons of soils in the Transbaikal region

The total mercury content has been determined in gray forest soils, chernozems, chestnut soils, and in different parent materials in the Transbaikal region. The mercury content is below the clarke value in the intrusive, effusive, and alluvial soil-forming rocks (0.004–0.024 mg/kg). In the humus horizons of the soils, it reaches 0.011–0.026 mg/kg, which is higher than the clarke value for the pedosphere. The mean background content of mercury in the soils of the Transbaikal region is 0.018 mg/kg. No significant positive correlation between the mercury content and the humus content of the soils has been revealed.     

The soil cover of the Selenga delta area in the Baikal region

The main regularities of soil development in the Selenga delta area of the Baikal region have been studied. The terraces of Lake Baikal and the Selenga River are occupied by soddy forest and gray forest soils. Intrazonal saturated and calcareous alluvial soils are formed on the Selenga floodplain and delta. Soddy soils of pine forests occur on natural levees along the streams; hollows and depressions are occupied by swampy soils.     

Boron in soils and plants of the West Transbaikal region

Some particularities of the distribution of boron in the main types of soils were studied. A close dependency between the boron content in the soils and its concentration in the soil-forming rocks (r = 0.85) was established, as well as the absence of a correlation between the content of boron and that of humus. It was found that boron is an element with an average intensity of accumulation in plants: the coefficient of its biological absorption from the soil of the steppe, meadow, and agrocenoses varied from 1.2 to 3.2. A correlation between the bulk content of boron in the soils and its accumulation in plants was absent (r = −0.07–0.11). The vegetation of a significant part of the steppe, dry-steppe, and forest-steppe landscapes had a boron deficiency (30–75%).     

Analysis of structure and composition of soil cover in the Salym-Irtysh interfluve based on updated medium-scale soil map

Specific features of the structure and composition of the soil cover in the Salym-Irtysh interfluve, Western Siberian Lowland, are studied with consideration of the capabilities of digital mapping. The properties of predominating and accompanying soils, which determine the modern status of boreal landscapes, are evaluated. Aspects of genesis and the Quaternary history of the investigated region are analyzed by a comparative approach. Possible trends of soil-plant cover transformation under climate changes are discussed.     

Impacts of rainstorms on soil erosion and organic matter for different cover crop systems in the western coast agricultural region of Syria

More and more cultivated coastal territories of Syria are being affected by increasing land degradation processes, specifically, by soil erosion due to non‐sustainable soil management. The use of cover crops can be considered an ideal solution to reduce the negative impacts of extreme rainfall events on soil erosion. However, there is no enough information about the main cultivated areas of Syria due to the current conflicts and the very few types of research conducted there. Therefore, the main aim of this research was to assess soil erosion (soil loss and sediment concentration) and hydrological response (run‐off and infiltration) considering the impact of different types of cropping systems on soil organic matter. To achieve this goal, using erosion plots, five grouped natural rainfall events and soil samples were collected, and infiltration measurements were performed between November 2012 and April 2013 (rainy season) on three different cropping systems (wheat, vetch, bean and control) with different sloping gradients (8% and 20%) in Tartous governorate (W Syria). Our results showed a cumulative rainfall amount from 68.8 to 201 mm during the study period. The highest sediment yield was generated in the control and wheat plots, registering 0.468 and 0.368 kg m^?2, respectively, with an inclination of 8%. For an inclination of 20%, the control and wheat plots registered 1.145 and 0.967 kg m^?2, respectively. In comparison with the control plots, there was a decrease in the total eroded organic matter, which ranged from 0.0579 (control) to 0.0289 (bean) kg m^?2 year^?1 in the plots with 20% inclination, and from 0.0233 (control) to 0.0069 (bean) kg m^?2 year^?1 with 8% inclination. To sum up, bean and vetch play an effective role to mitigate soil erosion, delay run‐off and reduce sediment yield. The output of this research provides first insights into the impact of different land uses on soil loss. Also, it could help rural inhabitants and farmers to correctly manage their soils against soil erosion processes.     

贵州西部山区土壤侵蚀研究

本文通过对影响贵州西部山区土壤侵蚀的自然因素和人为因素的分析研究,认为:该区已成为贵州省内土壤侵蚀最严重的地区之一,它将对乌江、红水河及长江、珠江流域的综合开发带来严重的危害。同时给本区国民经济的发展和人民生命财产的安全带来严重威胁。为此,作者在科学地论述了该区几种主要侵蚀类型、成因、危害等的基础上,指出加强防治这一地区的土壤侵蚀已成为刻不容缓的紧迫任务。     

Soil cover patterns and land resources in the south of the Selenga mountainous region

Soil cover patterns within the Kyakhta area of pine stands and the Kudarinsk area of dry steppes in the south of the Selenga mountainous region are characterized. The groups of soil combinations are shown on the map developed on a scale of 1: 500000. The areas of particular soils composing the combinations have been calculated. Thus, this small-scale soil map generally preserves information reflected on large- and medium-scale soil maps.     

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.     

On the components of soil humic acids (part 9)

The carbohydrates in soil organic matter seem to be derived from undecomposed or partially decomposed plant and microbial residues, In soil, these carbohydrates exist chiefly in such from as polysaccharide hemicellulose, and their polyuronide has been the chief object of investigation^1)-3). In various soil, the polyuronide is found in a large quantity in fulvic fraction of soil organic matter and has been considered as important in connection with the physical structure of soil^4),5). According to Lynch ⁵⁾, the carbohydrate content of humic acid is markedly smaller than that of fulvic acid. His work also indicates that a' considerable change is noted in the content and composition of the carbohydrate in humic acid because of the addition of some organic substances to the soils, or of the cultivation of virgin soils. Further, some investigators⁷⁾ believe that uronic acid is introduced into the aromatic structure of the humic acid by changing into pentose and furan. Accordingly, it seems that the role of carbohydrate in the formation of soil humic acid should not be overlooked.