Urban soil classification and properties. Some environmental problems of a large city (pollution of urban soils)

Keywords

URBAN SOILS / CLASSIFICATION / MEGAPOLIS / INTRODUCED HORIZON/ SOILS / CLASSIFICATION / PRINCIPLES / CHANGE

annotation scientific article on Earth sciences and related ecological sciences, author of scientific work - Aparin B.F., Sukhacheva E.Yu.

On the example of St. Petersburg, the genetic diversity of natural, anthropogenically transformed and anthropogenic soils of the metropolis was revealed. Changes in the composition of the soil cover under the influence of anthropogenic activity have been determined, and regularities in the formation of the soil cover on the territory of St. Petersburg over several centuries, starting from the 18th century, have been revealed. Variants of changes in the initial structure of the natural soil profile, which always accompany the process of urbanization, and features of the process of soil formation in urban conditions are considered. From the variety of surface bodies occurring in the urbanized area, objects were identified that correspond to the definition of soils - objects of the Classification and Diagnostics of Soils in Russia (KiDPR) and the International Reference Database (WRB). The principles of classification of soils in urban areas are determined. The characteristic of soils constructed by man, the basis of which is introduced ( introduced horizon) and its distinctive morphological features are determined. Concept introduced introduced horizon, consisting of human-modified material from humus or organogenic horizons of natural or anthropogenically transformed soils and having a sharp lower boundary with the underlying rock. The classification position of various soils of the metropolis in the system of KIDPR and WRB was determined. It is proposed to introduce a new section “Introduced Soils” in the trunk of synlithogenic soils in the system of KIDPR along with stratozems, volcanic, underdeveloped and alluvial ones. In the “Introduced soils” section, 6 types are distinguished according to the nature of the humus or organogenic horizon and the characteristics of the underlying rock. In the WRB system it is possible to introduce a new reference group in which soils with introduced horizon underlain by any mineral substrate of natural or anthropogenic origin.

Classification of urban soils in Russian soil classification system and international classification of soils

Based on the example of St-Petersburg a genetic diversity of natural, human-transformed and anthropogenic soils has been thoroughly studied at the urbanized territory of this city. Under consideration are changes in components of the soil cover caused by the human activities along with regularities in the soil cover formation that has being developed for several centuries from the beginning of the 18 th century. It is also shown how changed the initial profile of natural soils accompanying the urbanization process with special emphasis on peculiar features of the soil formation at the urbanized territory. Among a great variety of surface bodies at this territory the soils were found out, the definition of which is given in Russian soil classification system and WRB. The principles for classifying the urban soils are considered. The distinct morphological features of an introduced horizon are determined to give the comprehensive characteristics of human-transformed soils . Under discussion is the concept of “introduced horizon” composing of the human-modified material from the humus or organogenic horizons of natural soils and having the lower sharply expressed boundary with the bedrock. In Russian soil classification system it would be advisable to use a new order of “introduced soils” within the trunk of synlithogenic soils along with stratozems, volcanic, weakly developed and alluvial soils . In WRB it would be also possible to identify a new reference group of soils including the soils with the introduced horizon and underlying by any mineral substratum of natural or anthropogenic origin.

The text of the scientific work on the topic "Classification of urban soils in the system of Russian and international soil classification"

CLASSIFICATION OF URBAN SOILS IN THE SYSTEM OF RUSSIAN AND INTERNATIONAL SOIL CLASSIFICATION

B. F. Aparina, b and E. Yu. Sukhachevaa, b

1 St. Petersburg State University, Universitetskaya emb., 7-9, St. Petersburg, 199178, Russia V.V. Dokuchaeva, 199034, Russia, St. Petersburg, Birzhevoy proezd, 6 e-mail: [email protected]

On the example of St. Petersburg, the genetic diversity of natural, anthropogenically transformed and anthropogenic soils of the metropolis was revealed. Changes in the composition of the soil cover under the influence of anthropogenic activity have been determined, and regularities in the formation of the soil cover on the territory of St. Petersburg over several centuries, starting from the 18th century, have been revealed. Variants of changes in the initial structure of the natural soil profile, which always accompany the process of urbanization, and features of the process of soil formation in urban conditions are considered. From the variety of surface bodies encountered in the urbanized area, objects were identified that correspond to the definition of soils - objects of the "Classification and Diagnostics of Soils of Russia" (KiDPR) and the International Reference Database (WRB). The principles of classification of soils in urban areas are determined. The characteristic of human-designed soils, the basis of which is the introduced (introduced horizon), is given, and its distinctive morphological features are determined. The concept of an introduced horizon is introduced, consisting of man-modified material of humus or organogenic horizons of natural or anthropogenically transformed soils and having a sharp lower boundary with the underlying rock. The classification position of various soils of the metropolis in the system of KIDPR and WRB was determined. It is proposed to introduce a new section "Introduced Soils" in the trunk of synlithogenic soils along with stratozems, volcanic, underdeveloped, and alluvial, in the system of KIDPR. In the "Introduced soils" section, 6 types are distinguished according to the nature of the humus or organogenic horizon.

and according to the characteristics of the underlying rock. In the WRB system, it is possible to introduce a new reference group, which will combine soils with an introduced horizon underlain by any mineral substrate of natural or anthropogenic origin.

Key words: urban soils, classification, metropolis, introduced horizon.

The interest of scientists in the study of urban soils is steadily increasing following the increase in the areas of urbanized territories. Currently, more than 3/5 of the world's population lives in urban areas. The most urbanized states (except city states) are Kuwait (98.3%), Bahrain (96.2%), Qatar (95.3%), Malta (95%). In Northern and Western Europe, the urban population accounts for more than 80%. In Russia, built-up areas occupy 4.3 million hectares, and the number of inhabitants in cities is about 70%. The unlimited expansion of cities to the surrounding lands inevitably leads to a change in the global ecological potential of soils. The areas with an actively functioning surface occupied by natural and arable land are shrinking. Predicting the consequences of urbanization on global changes in the ecological functions of the soil cover is an urgent task facing soil scientists, which, in turn, cannot be solved without determining the place of urban soils in modern classification systems.

There is currently no generally accepted classification of urban soils either in Russia or in the world. One of the reasons for this is the lack of unified approaches to the nomenclature and taxonomy of urban soils. In the classification of soils officially adopted in Russia, which was published in 1977 (Classification and Diagnostics..., 1977) and is still in use today, soils in urban areas are not considered. In the "Classification and Diagnostics of Soils in Russia" (KiDPR) (2004), significant attention has already been paid to anthropogenically transformed soils.

A wide interest in the study of urban soils has arisen in recent decades (Stroganova and Agarkova, 1992; Burghardt, 1994; Soil, city, ecology, 1997; Bakina et al., 1999; Nadporozhskaya et al., 2000; Gerasimova et al., 2002; Rusakov, Ivanova, 2002; , Leh-

mann, Stahr, 2007, Rossiter, 2007; Matinyan et al., 2008; Aparin and Sukhacheva, 2010, 2013, 2014; Lebedeva, Gerasimova, 2011; Prokofieva et al., 2011, 2014; Shestakovi et al., 2014; Naeth at al., 2012). Original approaches and schemes for the nomenclature and taxonomy of urban soils were proposed for Moscow (Stroganova and Agarkova, 1992; Lebedeva and Gerasimova, 2011; Prokofieva et al., 2011), St. Petersburg (Aparin and Sukhacheva, 2013, 2014), Perm (Shestakov, 2014). In the field of urban soil classification, the works of German researchers are known (First International Conference, 2000; Lehmann and Stahr, 2007; Naeth at al., 2012), proposals of international working groups (SUITMA, INCOMMANTH, WRB) (Burghardt, 1994). An active search is underway for the classification position of urban soils in the system of KiDPR (2004) and WRB (2014) .

Obviously, when solving the problem of determining the classification position of urban soils, it is necessary to take into account that the soil cover in cities is fundamentally different from that in natural landscapes. Human impact on soils in an urbanized area manifests itself from a slight change in their properties to a radical transformation of the soil profile and the "creation" of new soil forms.

The soil cover of any city is heterogeneous and is characterized by significant spatial and temporal heterogeneity. This is due not only to the variety of natural conditions, but also to the varying degree and scale of human impact on the soil cover at various stages of the construction and expansion of the city, as well as in its different parts - in the center, on the outskirts, in forest parks, industrial areas and "sleeping" areas. districts (Aparin, Sukhacheva, 2013). In cities, human activity, as one of the factors of soil formation, manifests itself in indirect and direct impact on soils and soil processes. Indirect impact consists in modification of soil formation factors (precipitation, temperature, evaporation, vegetation, composition of parent rocks). The direct impact on soils is acidification, flooding, disturbance of the soil profile, as well as the formation or, in a way, the construction of a soil profile similar to the natural one.

On the territory of any city, elements of the soil cover of natural landscapes, agro-

landscapes and areas of dense urban development and industrial zones. In the natural ecosystems preserved within the city limits, differences of soils with a slightly disturbed structure dominate, in agrolandscapes, agrogenically transformed soils prevail, in areas with dense urban development, various surface formations are widespread: asphalt pavements, anthropogenically transformed soils, man-made soil-like bodies, mineral soils. Thus, the range of surface formations in the territory of any city is wide: from natural soils characteristic of a given geographical area to varying degrees of transformed soils and non-soil formations.

For example, when creating a soil map of St. Petersburg (scale 1: 50000), 18 types and subtypes of natural soils, 13 anthropogenically transformed, 4 anthropogenic soils were identified within the administrative boundaries of the metropolis (Aparin, Sukhacheva, 2014). Natural soils are presented at different stages of development (from the initial - petrozems and psammozems to climax). The soils of St. Petersburg have characteristic features associated both with the physical and geographical position of the city in the basins of the river. Neva and the Baltic Sea, and with the history of the formation of the ecological space of the city since the time of human settlement here (Aparin, Sukhacheva, 2013).

The soils of St. Petersburg have in their profile signs of a long centuries-old transformation under the influence of man, in which certain patterns are visible. Although man appeared on the territory of the Neva River as early as the Neolithic, his influence on soils was then minimal and had a point discrete character (table). Minor changes in the morphological appearance of soils, probably, were only in the territories of temporary camps of fishermen and hunters. In terms of the depth and nature of the impact on the soil profile, they did not differ from disturbances of natural origin that occurred, for example, during windblows.

Starting from the VIII-XI centuries. The Neva becomes the most important section of international waterways between the peoples of Eastern and Northern Europe, which significantly increased the load on the soil cover of the territory. In swampy and covered

the most drained lands near the rivers were first developed by the forests of the lands, where settlements subsequently developed over the centuries, the construction of which was

Changes in the composition of the soil cover under the influence of man in the territory of St. Petersburg_

Period New components in 1111 Nature of changes in 1111

Neolithic- Surface- Spot

13th century turbocharged

XIII- Surface-Fragmentary

18th century

stratified soils

abraded

agro natural

18th century Surface- Areal

turbocharged Expansion on natural

Abraded land

agro natural

Introduced

Stratozems

Oxidized gley

Agrozems

19th century Surface- Areal

turbocharged Expansion on natural

Stratified soils and agricultural

Abraded land

agro natural

Introduced

Stratozems

Oxidized gley

Agrozems

20th century Surface- Areal

turbocharged Stratification Expansion on natural

roved soils and agricultural

Abraded land

agro natural

Introduced

Stratozems

Oxidized gley

Agrozems

the reason for the appearance on the territory of the future metropolis of the first areas of stratified, abraded soils and, probably, stratozems. By 1500, there were already 410 villages on the territory of present-day St. Petersburg and the surrounding areas. Almost every village had small areas of cultivated soils: agro-soddy-podzols, agro-gray-humus, agro-soddy-podzolic. The process of land development was actively going on in the subsequent period. By the time the city was founded, the soil cover of the territory had already been significantly transformed by man - in addition to the developed soils with an agrohorizon, a relatively large area was occupied by disturbed soils to varying degrees.

The most radical changes in the soil cover of the city took place here in a relatively short period of time (300 years). The point and fragmentary nature of disturbances in the soil cover since 1703 becomes areal. The position of the historical center of St. Petersburg in the delta of the river. The Neva and constant floods made it necessary to raise the surface (the thickness of the cultural layer reaches 4 m or more in some parts of the city). Drainage works are being carried out, pavements are being created, alleys are being planted. Areas of disturbed soils on the territory of St. Petersburg under construction are growing rapidly and begin to exceed the size of areas of natural soils. Soil was added to raise the surface level, and humus material was applied to the lawns. The first areas of soils with a purposefully created humus layer appear.

In the central part of the modern city, all natural soils are destroyed or buried under the cultural layer. Instead, anthropogenic soils newly created by man, or less often stratozems, absolutely dominate (Fig. 1). They, as a rule, are formed on an anthropogenic layered substrate, which is currently the underlying, less often soil-forming rock. Its formation ended about 100-150 years ago. Thus, we know exactly the maximum time for the formation of the modern urban soil profile in the historical center of St. Petersburg.

Rice. 1. Scheme of the transformation of the natural soil profile in an urbanized area.

There are certain patterns in the formation of the soil cover of the city, which are reflected in its modern appearance.

Since its founding, the city has been constantly building up, first of all, already developed lands with agrozems or agro-natural soils. Therefore, buried arable horizons are often mentioned in studies of buried soils in St. Petersburg (Rusakov and Ivanova, 2002; Matinyan, 2008). The expansion of the city to arable land was constantly accompanied by the development of more and more new lands adjacent to the city limits, the cultivation of soils and their use for the production of agricultural products for the townspeople. This process has continued uninterruptedly for more than three centuries. The master plan for the development of St. Petersburg until 2025 provides for the expansion of the territory also at the expense of agricultural land. On the outskirts of St. Petersburg in the sleeping areas that were built in the 60-70s, many soils also bear traces of former development.

When determining the place of urban soils in modern classification systems, it is necessary to establish which of the urban surface formations (natural soils, anthropogenically transformed soils, soil-like bodies created by man, asphalt and other artificial formations) are objects of a particular classification system, (t .e corresponds to the definition of the object of classification).

Territories with artificial pavements, including asphalt ones, are not objects of the KiDPR, since these bodies do not meet the definition of a classification object. According to the KDPR, "the object of the basic profile-genetic classification is the soil - a natural or natural-anthropogenic solid-phase body exposed on the land surface, formed by the long-term interaction of processes leading to the differentiation of the original mineral and organic material into horizons" (Classification ..., 2004, a nine). At the same time, these surface formations can be considered in the WRB system, since the definition of objects in this classification system is broader.

The soils of parks, cemeteries, and some public gardens are, as a rule, anthropogenically transformed soils. They are fully consistent with the definition of objects of both classifications, and in the main have already been considered in both the KIDP and the WRB.

In the KDPR, soils whose profile reflects the results of anthropogenic impact are distinguished at various taxonomic levels, from divisions to subtypes. In the WRB system, two reference groups of soils are identified, the morphological appearance and properties of which have been significantly altered by humans: Anthrosols and Technosols, as well as a number of qualifiers. However, not all surface formations of cities, which can be related to soils, find their place in the WRB and KIDPR.

Principles of classification of soils in urban areas. The experience of studying and mapping the soils of St. Petersburg has shown that the classification of soils in urban areas can be integrated into the general structure of the KIDPR and WRB based on the following principles:

The unity of approaches to the classification of all solid-phase bodies exposed to the surface, which form the soil cover of the metropolis;

Recognition that the objects of soil classification of urbanized territories are both natural and anthropogenically transformed soils, as well as formations "designed" by man, which have introduced material of the humus (or organogenic) horizon on the surface;

Consideration of signs reflecting the degree and depth of anthropogenic transformation of the soil profile; human activity as a factor in soil formation leads either to the destruction of soils, or to their burial, mixing or movement of the material of soil horizons;

Taking into account not only the sequence of horizons (layers), but also the presence or absence of a genetic relationship between them (a sharp transition from one soil layer to the next in the absence of conjugated features between adjacent layers - removal and accumulation of matter);

Recognition that under the conditions of urban ecosystems, the profile-forming process occurring under the influence of natural factors is often accompanied by constant or periodic

step of material on the soil surface; this causes the upward growth of the soil profile and the formation of a layered stratum of different thickness and composition;

Recognition that for diagnosing horizons in anthropogenic soils and determining the classification position of these soils at the level of type in the KIDPR and qualifiers in the WRB, as well as for natural and anthropogenically transformed soils, traits inherited from natural soils are priority.

Search for the location of urban soils in KIDPR and WRB. To determine the classification position of various soils of a megalopolis in the system of KDPR and WRB, we consider possible variants of changes in the initial structure of the natural soil profile, which always accompany the process of urbanization (Fig. 2). There are only four types of changes in the soil profile under the direct influence of human activity: mixing of soil horizons, cutting off part of the profile, burying the soil, and "designing" a new profile.

During construction, soils are buried most often, and all the typographic horizons of the original soils are preserved. When a natural soil profile is buried with a layer of natural or artificial material of small thickness (up to 40 cm), bodies are formed that are classified in the KDPR at the subtype level as humus-, arti-, urbi-, and toxic-stratified soils (Figs. 2a, 2b). The WRB system uses the Novic qualifier for such soils (Figure 3.1). Soils, most of whose profile is represented by a humus stratified layer of introduced material, are united in the KDPR into the division of stratozems (Fig. 2e). In WRB, these are different antrosols (Fig. 3.2, 3.3). If the stratified stratum contains more than 20% of artefacts and more than 35% of the volume is construction waste, then the WRB qualifier for such soils is used for such soils.

Soil bodies that have retained their natural structure and are under asphalt ("sealed" soils) (Fig. 2c) are classified in the WRB as Bkgashs (Fig. 3.4). In the KDPR system, from our point of view, they should be considered only as buried soils of the corresponding genetic types, since they

soil name according to "Classification and diagnostics of Russian soils" 2004 soil name according to urban soil classification

Rice. 2. Types of changes in the soil profile under the direct impact of human activity in the system of the CIDPR.

Rice. 3. Types of changes in the soil profile under the direct impact of human activity in the WRB system.

are isolated (lose most of their connections) and do not perform most of the functions as natural biogeomembrane. Isolated from the environment, such soils cannot adsorb the metabolic products of a megacity, transform and transport pollutants, and do not perform a sanitary, water, gas, and thermoregulatory function.

Studies of soils in St. Petersburg have shown that buried natural soils are deep below the surface and are covered not only by asphalt, but also by anthropogenic layers of various thicknesses.

When reducing tree vegetation or leveling the surface, only the upper part of the natural soil profile can be disturbed. Such soils are classified as turbated at the subtype level in the natural soil types (Fig. 2f). With long-term mixing of the upper horizons associated with agricultural tillage, agro-natural soils and agrozems are formed in KiDPR (Fig. 2f) and Litigsgdgd in WRB (Fig. 3.7, 3.8).

As a result of cutting one or two surface horizons, abraded soils are formed (Fig. 2g). At a deeper cut, when a median horizon, to some extent preserved, emerges on the day surface, the soil belongs to the abrazem division (KiDPR) (Fig. 2h). Often, during construction, the soil is completely destroyed, and rock appears on the surface; in this case, abralites are distinguished, which are no longer soil, but an technogenic surface formation, which is considered beyond the classification system of the KDPR (Fig. 2i)

A layer of artificial material or rock deposited on the surface (Fig. 2d) can also be considered only as a technogenic surface formation (Lebedeva, Gerasimova, 2011) or Technosols in WRB (Fig. 3.6) (Sukhacheva, Aparin, 2014).

Thus, in the WRB system, variants 1-3 and 7-9 (Fig. 3) are considered as soils of different reference groups with qualifiers Novic, Urbic, Ekranic, Antric. Options 4-6 - Technosols. Option 10 - breed. Only soils with an introduced humus horizon lying on a mineral rock remain (Fig. 3.13).

Within the framework of the KDPR, all the options considered, except for one, either have their place in the system, or are not objects of this soil classification. The remaining option is an anthropogenic soil “constructed” by man (Fig. 2j), in which the introduced humus or peat horizon of natural soils overlaps the natural or artificially created mineral strata. Man, being one of the factors of soil formation (by no means obligatory), cannot himself create soil in the classical (scientific) sense of it. Based on the target function - to provide conditions for the growth and development of plants - a person creates a physical model of the root layer, and not the soil profile as such.

In agricultural landscapes, a person purposefully changes the chemical composition, properties and regime of the soil in order to most effectively use its most important function - fertility. At the same time, the genetic profile of the soil, as a rule, changes insignificantly. In urbanized areas, in order to achieve the same goal, a person is forced to con-

to stream soil-like formations with a fertile root-inhabited layer, introducing organic-mineral or organogenic soil material from the outside - a product of long-term natural soil formation, which was formed under a different ratio of factors. As a rule, this material is taken from various soils of the adjacent territories and applied either to the preserved horizons of the former soils, or to the natural rock that appeared on the surface as a result of the destruction of the soil profile or moved during construction, or to an artificially created mineral stratum. Thus, the most biologically active part of the soil is transferred from its natural range to the urbanized area. Although soil formation, as a special form of matter movement immanent in nature, begins immediately after the stabilization of the day surface on all mineral and organo-mineral substrates, it takes hundreds of years to form a system of genetic horizons in the surface layer.

In a new alien (urbanized) environment, a new human-designed soil profile, most of the morphological features that make it possible to identify the type of displaced horizons are preserved. At the same time, some properties purposefully or accidentally modified by humans may differ significantly from the initial properties of these horizons in natural soils. The term “introduced”, accepted in biology, can be applied to the displaced soil material, and the purposeful introduction of the material of the humus (peat, peat-mineral) horizon into an urbanized environment is a kind of technogenic introduction, similar to the introduction of plants. As a result, soils with an introduced horizon are formed, which have characteristic morphological features, which, on the one hand, are inherited from the parent soil, and, on the other hand, are associated with anthropogenic impact.

The introduced humus or organogenic horizon with a thickness consists of the material introduced and modified by man of the humus or organogenic horizons of natural or anthropogenically transformed soils and has

a sharp lower boundary with the underlying mineral substrate - the underlying rock, which usually differs from natural ones both in composition and in structure. The horizon is often heterogeneous in composition, composition, and density.

A distinctive feature of the underlying rocks is, as a rule, their heterogeneous composition and structure. They contain a significant number of inclusions - artifacts of various composition, size and volume and are characterized by the presence of geochemical barriers, sharp gradients in water permeability, thermal conductivity, and water-holding capacity.

It is especially important that in the profile of such soils, the humus or organogenic horizon always lies on the rock that is underlying for it, and not the parent (soil-forming). Most of the "new" soils do not have the typomorphic features characteristic of natural soils. The system of mineral-energy metabolism in the profile of such soils is not balanced, and the absence or weak manifestation of the genetic relationship between the layers indicates the initial stage of the formation of the soil profile.

Proposals for the introduction of new taxa in the KIDP. A feature of the process of soil formation in urban conditions is the rejuvenation of the soil profile as a result of constant or periodic anthropogenic input of humus material to the soil surface. When evaluating the age of soils in urban areas, it should be taken into account that the age of the introduced humus horizons, as well as the underlying mineral stratum, can be very large, up to several thousand years, while the age of the soil profile itself may not reach even a year. In a metropolis, the soil-forming process, on the one hand, has no fundamental differences from the natural one, and on the other hand, its speed in the city is much higher.

The basis for the classification of soils with an introduced horizon, as well as natural soils, is the morphological and genetic analysis of the profile: structure, composition, and properties. For the conditions of St. Petersburg, a profile depth of up to 100 cm is taken into account, i.e. to the lower boundary of a clear manifestation of soil formation processes in the natural soils of the region, differentiating the profile into genetic horizons.

When developing a classification of soils in megacities, it is necessary to put the thickness of the humus or organogenic horizon at a high taxonomic level, with which most of the functions performed are associated. The degree of genetic connection between the layers, their correspondence to the profile-forming processes characteristic of the soils of this natural zone, the origin and composition of the surface horizon should also be taken into account.

Taking into account the specific structure of anthropogenic soils and the peculiarities of soil formation in urban conditions, it is proposed to introduce a department in the trunk of synlithogenic soils along with stratozems, volcanic, underdeveloped and alluvial soils in the KDPR system: Introduced soils.

The division includes soils in which an introduced humus or organogenic horizon (I) less than 40 cm thick rests on a mineral substrate (D) formed in situ or introduced from outside.

If an introduced horizon less than 40 cm thick rests on undisturbed soil or any median horizon, the soil is classified within the framework of the CIP as a humus-stratified subtype within the relevant type; when the thickness of the introduced horizon is more than 40 cm, the soil is diagnosed as a stratozem.

In the section Introduced soils, 6 types of soils were distinguished according to the nature of the humus or organogenic horizon and the characteristics of the mineral substrate. In all types, it is possible to distinguish subtypes by the presence of signs in the underlying substrate, indicating the mechanisms of its formation.

Typical soils (in situ) I-D: the underlying mineral sequence shows no signs of mechanical movement. Typical introduced soils are formed when an introduced horizon is piled on a parent rock that has been preserved from destroyed soil.

I-RDur urbostratified soils are distinguished by well-pronounced layering, often with a large proportion of industrial inclusions (bricks, construction and household waste, expanded clay, gravel, artifacts, etc.). The thickness of the underlying urbostratified mineral strata can reach several meters, and the subtypes

Such soils are typical for areas where construction work has been repeatedly carried out.

Urb-filled soils LJB: the underlying mineral stratum is heterogeneous in composition and composition, often contains artifacts; fuzzy layering indicates stratification of the material. Similar subtypes are formed at the construction or repair site of various underground utilities. The underlying mineral stratum in most cases has a thickness of no more than 2 m and is underlain by a rock that has a natural composition.

Urbolayered-humus soils I-RDur[h]: are distinguished by well-pronounced layering, often with the inclusion of buried introduced humus layers. In St. Petersburg, gray-humus urbolayer-humus subtypes were found in public gardens and parks in the central part of the city.

The areas of these soils are pointwise located among asphalt pavements and occupy from 5 to 20% of the area. The soils are formed on anthropogenic layered deposits - the "cultural" layer, reaching 4 m or more in some parts of the city. The reason for the uniformity of the component composition of the soils of the "old city" is their similar origin. The introduced humus horizon in small squares and lawns inside St. Petersburg courtyards gradually over more than three centuries periodically (with each new repair or construction of buildings) was covered with a layer of construction debris. Then a new humus layer was formed or artificially applied. Thus, the vast majority of soils in the quarters of the "old city" are introduced gray-humus urbislayer-humus soils. Soils formed on a layered cultural stratum without humus interlayers are much less common.

Water-accumulative soils (reclaimed soils) I-Daq: the underlying mineral stratum is homogeneous in composition and has a thin layering. In the coastal areas of St. Petersburg, alluvial deposits predominate among soil-forming rocks. As a rule, they are layered and resemble alluvial deposits.

In addition to the listed subtypes specific for the types of introduced soils, it is possible to distinguish subtypes according to

native features, for example, gleying, carbonate, ferruginous, which is reflected by complex subtypes.

In the WRB system, based on the above principles, it is possible to introduce a new reference group, which will combine soils with an introduced horizon underlain by any mineral substrate.

The inclusion of natural, anthropogenically transformed soils and anthropogenic soils in a unified classification scheme makes it possible to consider the diversity of soils and their changes in the soil cover of any city both in space and in time from a unified standpoint.

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CLASSIFICATION OF URBAN SOILS IN RUSSIAN SOIL CLASSIFICATION SYSTEM AND INTERNATIONAL CLASSIFICATION OF SOILS

B. F. Aparin1" 2, Ye. Yu. Sukhacheva1" 2

1Saint Petersburg State University, Universitetskaya nab. 7-9 St. Petersburg, 199034 Russia 2Dokuehaev Central Soil Science Museum, Birzhevoi proezd, 6, St. Petersburg, 199034 Russia [email protected]

Based on the example of St-Petersburg a genetic diversity of natural, human-transformed and anthropogenic soils has been thoroughly studied at the urbanized territory of this city. Under consideration are changes in components of the soil cover caused by the human activities along with regularities in the soil cover formation that has being developed for several centuries from the beginning of the 18th century. It is also shown how changed the initial profile of natural soils accompanying the urbanization process with special emphasis on peculiar features of the soil formation at the urbanized territory. Among a great variety of surface bodies at this territory the soils were found out, the definition of which is given in Russian soil classification system and WRB. The principles for classifying the urban soils are considered. The distinct morphological features of an introduced horizon are determined to give the comprehensive characteristics of human-transformed soils. Under discussion is the concept of "introduced horizon" composing of the human-modified material from the humus or organogenic horizons of natural soils and having the lower sharply expressed boundary with the bedrock. In Russian soil classification system it would be advisable to use a new order of "introduced soils" within the trunk of synlithogenic soils along with stratozems, volcanic, weakly developed and alluvial soils. In WRB it would be also possible to identify a new reference group of soils including the soils with the introduced horizon and underlying by any mineral substratum of natural or anthropogenic origin.

Keywords: classification, soils, principles, change.

The development of urban ecosystems, unlike natural ones, is determined not so much by natural processes as by human activity. Therefore, in the city there is a significant transformation of all factors of soil formation (climate, relief, soil-forming rocks, vegetation). The natural soil cover in most of the modern cities has been destroyed.

The differences between the main components of urban ecosystems and their natural counterparts are well studied. Let us present some results of urban ecologists' research in order to imagine the specifics of the urban environment. Most of the data refers to large cities such as Moscow.

Climate specifics. The man who built the great cities had an active influence on the landscape and thus on the original climate. Some researchers insist on the need to identify such a variety of climate as urban.

Differences in the climate of the city and its environs are sometimes equivalent to a latitudinal shift of 200-300 km to the south. Islands of heat and dust are created in the atmosphere, which significantly affect air temperature and precipitation. The city center is on average warmer than its outskirts and suburbs. The daily temperature variation in the city is not as pronounced as in the surrounding area. Thus, the air temperature in Paris is higher than in the surrounding area, on average per year by 2 ° C, in New York (at times) by 10-15 ° C. An increase in building density and asphalting from 20 to 50% increases the difference in maximum summer temperatures in the center and around the city from 5 to 14°C. The center of heat over the city is also observed in daily temperature minima.

Due to the "sealing" of the surface, most of the precipitation bypasses the soil body, and the intense heating of asphalt surfaces and urban structures contributes to overheating of the soil.

Increased convection in the atmosphere of the city, as well as technogenic dustiness, lead to an increase in the number of thunderstorms over the city, an increase in the intensity of showers and the total amount of precipitation. Winter precipitation can reach 150%, summer - 115% of the norm. Annual precipitation totals are increased in Moscow by 25%, which is commensurate with the effect of intentional influence on cloudiness. The surface runoff of the urbanized area is twice as high. All these circumstances make industrial cities hotbeds of planar and gully erosion even where it has never been seen before.

Rice. 10.3.

In cities, there is sometimes a lack of snow cover or a sharp change in the timing of its formation. In cities, the snow cover changes significantly in comparison with the natural one. In different places of the city, the snow is removed, trampled down, poured in excess of the norm by the person himself or by the winds. This creates areas (microlandscapes) with a specific microclimate, often unparalleled in the enclosing soil-geographical zone. In areas exposed to snow, conditions of an arid cold desert arise, which in their natural state correspond to skeletal, primitive, deflated soils and sparse vegetation in "scale" and "cushion" forms. In areas with excess snow, especially in shaded areas, a microclimate and seasonal regime (phenophases) are created that are close to forest and forest-meadow landscapes, causing soil-forming processes characteristic of them.

Depending on the lithological and topographic conditions, the processes of permafrost heaving of the soil and soil and solifluction slumping can be intensified.

Greater warming and humidification of the air and soils of the urban area compared to the surrounding area improves the living conditions of terrestrial vegetation and soil fauna and increases the growing season, although in some cases the opposite occurs in the city (Fig. 10.3).

All these climate features are present in any large city, but their effect increases with the size of the agglomeration.

Relief. The economic and construction activities of man for many centuries have significantly changed the natural relief. Happening:

surface leveling;
disappearance of the valley-beam network;
creation of a new relief (for example, terracing or cutting off the surface layer);
backfilling of a fine erosion network.

It is known that on the territory of ancient urban settlements there is a noticeable rise in the level of the earth's surface, called "tel". The Tel rises 8-10 m above the surroundings; it was formed as a result of the systematic introduction of various kinds of substrates onto the urban surface of the earth. According to N.S. Kasimov and A.I. Perelman (1995), the relief of the city affects not only the water, but also the air migration of pollutants.

In cities, karst-suffusion subsidence, subsidence of the soil stratum as a result of the increasing flow of underground artesian waters, a decrease in the volume of soil and ground mass caused by the leaching of soluble salts and lime are often observed. Settlements appear in post-construction bulk soils and during planning ground work, as well as on the surface in the form of closed depressions: saucers, depressions, funnels and cracks. As a result of the negative impact of karst-suffosion processes, degradation of the soil and plant complex often occurs.

Soil-forming rocks. Soil-forming rocks in cities can be:

natural substrates occurring in situ;
cultural layer;
bulk soils;
alluvial soils.

Rice. 10.4.

cultural layer is a historically established system of strata formed as a result of human activity. The thickness or thickness of the cultural layer can vary from a few centimeters to tens of meters (in Saratov up to 12 m, in Moscow up to 22 m) and is characterized by variegation even within small areas.

The formation of the cultural layer occurs through the surface accumulation of various kinds of material as a result of human household activities or through the transformation of the upper natural layer during construction and landscaping, with the introduction of foreign materials into the natural soil.

The composition of the cultural layer in modern cities includes a wide variety of impurities - broken bricks, stone, construction debris, various household items, abandoned building foundations, cellars, wells, log and boardwalks, cobblestone and asphalt pavements. Construction debris usually predominates among these deposits. The strata of the cultural layer at different historical times could play the role of soil, acquiring the features of its structure. Thus, the cultural layer is an uneven-aged system of buried urban soils (Fig. 10.4).

Rice. 10.5.

The growth of the territory of cities occurred gradually. At first, the fortress walls served as the border of the city, then the fragmentary development of the suburbs turned into a continuous one, the city line expanded, and the city acquired new suburbs (Fig. 10.5).

Figure 10.6 illustrates the stages of increase in the territory of Moscow. The figure shows that the central regions have been under the pressure of urban genesis for centuries. In the XX century. the rate of expansion of the urban area has increased many times over. Consequently, the territory of ancient large cities, such as Moscow, Novgorod, Kyiv, etc., can be divided into two main zones according to the nature of the substrates: the zone of an ancient settlement with a thick cultural layer and the zone of young building with an underdeveloped cultural layer, fresh and old soils, on which natural soils of varying degrees of disturbance are preserved and thin, underdeveloped urban soils are formed.

Soils. The whole spectrum of loose sedimentary deposits and rocks common in the surrounding area is also found in the city. In cities, there is a deep change in the soil. Thus, the depth of laying the foundations of ground structures extends up to 35 m, the underground up to 60-100 m. This not only leads to soil mixing, but also changes the direction of groundwater flow.

Thus, the formation of urban soils can occur:

on the cultural layer;
on natural soils of different genesis, consisting of organo-mineral soil material and the remains of natural soils (“soil on soil”);
on natural and technogenic bulk or alluvial soils (“soil on soil”).

Rice. 10.6.

1 - Kremlin, 1156; 2 - the border of the White City, 1593; 3 - Kamer-Kollezhsky shaft in 1742; 4 - border of 1917; 5 - border according to the General Plan of 1935; 6 - MKAD, 1960; 7 - modern boundaries of the city. (From the book "Moscow - Paris. Nature and urban planning", 1997)

Vegetation cover. Urban flora does not completely lose its zonal features, and the process of landscape anthropogenization in cities is controlled by zonal climatic conditions. However, in the cities of the forest zone, the vegetation acquires a more southern appearance due to warmer arid conditions.

The urban flora is formed from local native species and introduced, imported, alien species. Features of urban flora (Kavtaradze, Ignatieva, 1986) are:

the richness of the floristic composition, originally due to the ecotone effect;
floristic heterogeneity of the city, due to its ecological, geographical and age heterogeneity. From the outskirts of the city to its center, the number of species of the floristic composition naturally decreases.

D.N. Kavtaradze and M.I. Ignatieva (1986), M.I. Ignatieva (1993) developed a classification of urban plant communities using the term "urban phytocenosis" (UFC). It is based on the origin of UVC and the dominant life form of plants. Table data. 10.2 give an idea of the diversity of UFCs.

Table 10.2

Urban phytocenoses and their complexes (Ignatieva, 1993)

Communities dominated by trees and shrubs	Communities grassy plants	Landscape gardening complexes, i.e. a combination of fragments of woody, shrubby and herbaceous vegetation
A. Natural origin		1. Parks (gardens) 2. Squares 3. Inter-quarter plantings 4. Boulevards 5. Special purpose (planting hospitals, kindergartens, institutes, industrial zones) 6. Street landings
1. Tree massifs of forest parks and parks	1. Meadows of forest parks 2. Swamps of forest parks
B. Artificially spho	reinforced
1. Woodlands and groups of parks 2. Hedges	1. Lawns 2. Flower beds
B. Spontaneous
1. Wastelands

Ecological differences in urban natural complexes are very significant. The properties of natural complexes are most fully observed in urban forests, forest parks and old parks, in which the natural biological cycle is preserved, although it is regulated by man. The remaining types of UFC are usually characterized by artificially formed plant communities, and their ecological functioning is largely determined by the human contribution: removal of fallen leaves, application of organic and mineral fertilizers, etc. The worst growing conditions are characterized by trees in holes, surrounded on all sides by asphalt. Edge burn of leaves, decrease in decorative effect, change in morphological structure are associated with unfavorable air and especially soil conditions.

Toxic substances found in the soil itself affect vegetation to a greater extent than gas emissions from transport and industrial enterprises into the atmosphere. Damage to trees and shrubs may be a response to environmental toxicity. The result is:

accelerated death of the branches of the main part of the crown;
decrease in linear growth of the axis of the trunk and branches;
weakening of shoot formation due to the death of the kidneys;
change in the habitus of young trees, etc.

Thus, damage to trees and shrubs may be a response to environmental toxicity.

With a strong dust content in the air in the city, the ability of green spaces to capture dust and aerosols is of great importance. During the growing season, trees capture 42% of air dust, and during the leafless period - 37%. Lilac and elm have the best dust-proof properties, oak (up to 56 t/ha) and spruce (32 t/ha) absorb dust less.

Plantings have a positive effect on the thermal regime of both adjacent territories and intra-quarter development. Inside the building, the temperature is higher than in the surrounding green spaces, and the difference sometimes reaches 2-3°C.

Planted areas can increase the humidity of the air. The evaporating surface of the leaves of trees and shrubs, the stems of grasses and flowers is 20 times or more greater than the area of soil occupied by this vegetation.

Green spaces also absorb heavy metals from the air, which somewhat reduces their concentration. So, more lead is absorbed by poplar and Norway maple, and sulfur - by small-leaved linden and Norway maple. The crown of coniferous trees adsorbs lead, zinc, cobalt, chromium, copper, titanium, molybdenum.

Land use as a factor of urban pedogenesis. The structure and nature of land use is a shaping factor in the development of soils in the city. One of the important factors of soil formation is the type of functional land use: residential development, industrial zone, forest park, etc.

The urban area is a variety of land types with different functional purposes. Each type, along with general indicators, has its own characteristics peculiar only to it.

In any large city, the following categories of land are distinguished:

lands of urban and rural development - residential part (yard spaces, squares, kindergartens and schools, lawns along highways);
public lands - industrial zones (plants and factories, car fleets, thermal power plants, warehouses, gas stations, stations and aeration fields, highways, airports, railways, etc.);
lands of natural recreational and nature protection zones (urban forests, forest parks, parks, boulevards, squares, natural monuments, etc.);
land for agricultural use (arable land, farms, nurseries, experimental fields);
reserve lands (wastelands, landfills, quarries, inconveniences).

Each of the above categories of urban land consists of:

a) sealed areas (impermeable) under residential buildings, roads, sidewalks, warehouses and production facilities and other buildings and communications. These lands are deprived of natural water and air exchange;
b) open unsealed (permeable) territories, which are soils, soil-like bodies of varying degrees of anthropogenic disturbance. It is the unsealed urban lands that perform the sanitary-hygienic, ecological and biospheric functions that are so important for a full-fledged quality standard of living for the urban population.

In turn, open unsealed territories can be divided into:

a) landscaped areas covered with vegetation, with soils covering them that retain ecological functions (squares, parks, forest parks, lawns, etc.);
b) vacant or weakly cultivated territories, where the vegetation is fragmented and represented mainly by ruderal species or weeds (wastelands, courtyard spaces, etc.). The ecological functions of the soils developed there are transformed, degraded, or severely disturbed. Such territories are found in all categories of land.

Soils bear the imprint of the quality and type of land use. This suggests that the type of land use - formation - Jlj key factor in the evolution of soils in urban and industrial areas. III The urban way of land use affects all factors Yu> soil formation tori. On the other hand, the functional use of the territory directly determines the intensity and nature of the impact on the soil profile.

The specific factors of soil formation in urban soils are:

the structure and nature of economic land use in the city;
special urban microclimate equivalent to a latitudinal shift of 200-300 km;
bulk natural substrates and the cultural layer and the presence of building and household inclusions in them;
changes in vegetation associated with the characteristics of the urban microclimate;
aerosol and intrasoil pollution.

The soil cover of the urban area is represented by natural soils of varying degrees of disturbance and soils of anthropogenic origin (soils or, as they are now commonly called, urbanozems). The bulk of the soil in the city is under a layer of asphalt, under houses and under lawns. Natural soils can be found only in areas of natural forests located within the city.

The system of horizons in urban soils, their thickness, and morphological expression vary greatly in different parts of the urban area. There is a complete disappearance of some horizons (A 1, A 1 A 2 , A 2 B) or a violation of their sequence, the appearance of bleaching and gleying at the contact of layers of different granulometric composition. In the steppe zone, in urban soils there are no horizons A, AB, and often horizon B 1, there are inclusions of debris, brick fragments, etc.

Soils of varying degrees of disturbance, as a rule, are confined to peripheral areas, residential areas. These soils combine the undisturbed lower part of the profile and anthropogenically disturbed upper layers. According to the method of formation, the top layer can be bulk, mixed or mixed-bulk. The disturbance may affect the humus-accumulative horizon, and may reach the illuvial horizons. So, the profile of slightly disturbed soddy-podzolic soil has the following structure: U↓ (0...25 cm) - urbanized layer formed as a result of mixing soil layers, dark gray, with inclusions of bricks, household waste; horizons follow: A 2 B, B 1, B 2 and C.

The profile of soddy-podzolic heavily disturbed soil includes horizons: U 1h (0...15 cm) - urbanized humus layer of dark gray or gray color with inclusions; U 2h ↓ (15...50 cm) - an urbanized layer with dripping humus along the roots, gray or light gray in color, contains an abundance of household or industrial inclusions; gradually passes into horizon B 1 further into horizons B 2 and C.

Most urban soils are characterized by the absence of genetic soil horizons A and B. The soil profile is a combination of anthropogenic layers of different color and thickness with inclusions of household, construction, industrial waste (U 1, U 2 , U 3, etc.). Such soils, or urbanozems, are typical for the central part of cities and territories of new buildings.

The soils of lawns and squares have a peculiar soil profile. It is distinguished by a large thickness of the humus horizon and a humus-peat-compost layer (70...80 cm or more), which develops in the lower illuvial part of the soil profile.

Compared with natural conditions in the city, there is a change in all factors of soil formation, the main of which is human activity.

The thermal regime of soils changes greatly. The temperature of the soil on the surface is on average 1...3 °C (10 °C) higher than that of the surrounding area. To a greater extent, this is observed on highways and in areas with high building density. From the inside, the soils are heated by the city heating network. In this regard, early snow melts, and the growing season of plants increases.

The presence in the city of significant watertight areas with reduced infiltration capacity causes a significant change in the drainage process. This is manifested in a decrease in time, an increase in the volume and intensity of runoff, which leads to an increase in erosion processes, as well as soil washout. As a result of such unfavorable phenomena, there is a decrease in moisture reserves in the root layer.

Leveling of relief forms is observed in cities: falling asleep of ravines, cutting off hills and slopes.

A characteristic feature of urban soils is the absence of litter, and where it is present, its thickness is very small (no more than 2 cm). The granulometric composition of soils and soils is predominantly light loamy, less often sandy loamy and medium loamy. The admixture of skeletal material in anthropogenically disturbed soils reaches 40...50% or more. In the soils there are inclusions of a domestic nature. Due to the high recreational load, a strong compaction of the soil surface is observed. The bulk density is mainly 1.4 ... 1.6 g / cm 3, and in residential areas - up to 1.7 g / cm 3.

A distinctive feature of urban soils is their high pH value. Exchangeable acidity averages 4.7...7.6, which is much higher than in the soils of nearby areas (3.5...4.5).

It should be noted that the formation of the soil cover occurs with the active change of soil-forming rocks, fragmentation of the structure due to partial sealing with artificial coatings, depreciation or degradation up to the complete replacement of soils in some areas.

Urban soils are anthropogenically modified soils that have a surface layer more than 50 cm thick created as a result of human activity, obtained by mixing, pouring or burying material of urban origin, including construction and household waste.

Common features of urban soils are as follows:

parent rock - bulk, alluvial or mixed soils or cultural layer;
inclusion of construction and household waste in the upper horizons;
neutral or alkaline reaction (even in the forest zone);
high pollution with heavy metals (HM) and oil products;
special physical and mechanical properties of soils (reduced moisture capacity, increased bulk density, compaction, stonyness);
upward growth of the profile due to the constant introduction of various materials and intensive eolian spraying.

The specificity of urban soils is the combination of the listed properties. Urban soils are characterized by a specific diagnostic horizon "urbic" (from the word urbanus - city). The "urbic" horizon is a surface organo-mineral bulk, mixed horizon, with urboanthropogenic inclusions (more than 5% of construction and household waste, industrial waste), more than 5 cm thick (Fedorets, Medvedeva, 2009).

As a result of anthropogenic impact, urban soils have significant differences from natural soils, the main of which are the following:

formation of soils on bulk, alluvial, mixed soils and the cultural layer;
the presence of inclusions of construction and household waste in the upper horizons;
change in acid-base balance with a tendency to alkalization;
high pollution with heavy metals, oil products, components of emissions from industrial enterprises;
changes in the physical and mechanical properties of soils (reduced moisture capacity, increased density, stoniness, etc.);
profile growth due to intensive deposition.

Some groups of urban soils can be distinguished: natural undisturbed soils that retain the normal occurrence of natural soil horizons (soils of urban forests and forest parks); natural-anthropogenic surface-transformed, the soil profile of which is changed in a layer less than 50 cm thick; anthropogenic deeply transformed soils formed on the cultural layer or bulk, alluvial and mixed soils with a thickness of more than 50 cm, in which physical and mechanical rearrangement of profiles or chemical transformation due to chemical pollution has occurred; urbotechnozems are artificial soils created by enrichment with a fertile layer, peat-compost mixture of bulk or other fresh soils. In the city of Yoshkar-Ola, in the Zarechnaya part of the city, a whole microdistrict was built on artificial soil - sand, which was washed up from the bottom of the river. Malaya Kokshaga, the thickness of the soil reaches 6 m.

Soils in the city exist under the influence of the same factors of soil formation as natural undisturbed soils, but in cities anthropogenic factors of soil formation prevail over natural factors. The features of soil-forming processes in urban areas are as follows: soil disturbance as a result of the movement of horizons from natural places of occurrence, deformation of the soil structure and the order of the soil horizons; low content of organic matter - the main structure-forming component of the soil; a decrease in the number of populations and activity of soil microorganisms and invertebrates as a result of a deficiency of organic matter.

Significant harm to urban biogeocenoses is caused by the removal and burning of foliage, as a result of which the biogeochemical cycle of soil nutrients is disrupted; soils are constantly becoming poorer, the condition of the vegetation growing on them is deteriorating. In addition, the burning of leaves in the city leads to additional pollution of the city atmosphere, since in this case the same harmful pollutants enter the air, including heavy metals that were sorbed by the leaves.

The main sources of soil pollution are household waste, road and rail transport, emissions from thermal power plants, industrial enterprises, sewage, construction debris.

Urban soils are complex and rapidly developing natural and anthropogenic formations. The ecological state of the soil cover is negatively affected by production facilities through emissions of pollutants into the atmospheric air and due to the accumulation and storage of production waste, as well as vehicle emissions.

The result of long-term exposure to polluted atmospheric air is the content of metals in the surface layer of urban soils, associated with a change in the technological process, the efficiency of dust and gas collection, the influence of metrological and other factors.

As the results of a number of studies have shown (Voskresenskaya, 2009), the content of heavy metals - lead, cadmium, copper and zinc is unevenly distributed over the territory of the city of Yoshkar-Ola (Tables 5-6). Analyzing the research data, it should be noted that the concentration of heavy metals in the city as a whole does not have a clearly defined direction, rather it has a mosaic distribution.

Table 5 - The content of heavy metals in the soil of the city of Yoshkar-Ola
(Voskresenskaya, 2009)

№	Study area, streets	Content of heavy metals, mg/kg
№	Study area, streets	lead	cadmium	copper	zinc
forest park zone
1	PA "Pine Grove"	4.2±0.01	0.9±0.01	2.2±0.01	21.5±0.03
Industrial and residential areas
2	Krasnoarmeyskaya	146.5±8.46	1.6±0.06	45.6±2.63	169.6±9.79
3	Soviet	28.1±1.33	1.2±0.01	22.7±1.08	173.7±8.87
4	Lunacharsky	47.0±2.13	0	20.8±1.09	141.3±7.58
5	machine builders	35.0±0.05	0.5±0.01	104.9±0.96	37.5±0.01
6	Warriors of the Internationalists	22.5±0.02	0.7±0.01	37.5±0.31	96.7±0.02
7	Tap water	27.5±0.01	0.5±0.03	25.0±0.03	13.8±0.01
8	Pushkin	34.2±0.02	2.0±0.01	35.2±0.03	12.7±0.01
9	Panfilova	25.0±0.02	0	86.5±0.05	33.8±0.01
10	Karl Marx	30.7±0.02	0	21.0±0.06	82.2±3.02
11	Leninsky Prospekt	51.7±0.01	0.5±0.01	82.7±0.02	112.5±8.42
12	Kirov	40.0±0.03	0	25.5±0.03	38.2±0.03
13	Dimitrova	29.2±0.03	0.9±0.02	25.5±0.06	33.7±0.01
14	communist	32.4±0.03	0	21.7±0.03	98.0±7.01
15	Ashkinin	36.7±0.03	0	35.2±0.03	94.2±0.51
16	Eshpaya	34.2±0.04	0	38.0±0.06	92.3±3.01
17	YvanaKyrli	93.5±0.04	0	92.5±0.05	232.5±7.02
18	Karl Liebknecht	51.4±0.09	0.4±0.01	38.3±0.12	72.3±1.12
	Average content in the city, without protected areas	48,5	0,5	42,3	96,2
	MPC (gross content)	130,0	2,0	132,0	220,0

Table 6 - Values of the complex soil pollution index, Zc
(Voskresenskaya, 2009)

№	Study area	Zc	Pollution level assessment
1	Krasnoarmeyskaya	24,97	moderately dangerous
2	Soviet	13,62	admissible
3	Lunacharsky	11,51	admissible
4	machine builders	34,94	dangerous
5	Warriors of the Internationalists	24,79	moderately dangerous
6	Tap water	7,03	admissible
7	Pushkin	11,37	admissible
8	Panfilova	28,08	moderately dangerous
9	Karl Marx	8,54	admissible
10	Leninsky Prospekt	31,34	moderately dangerous
11	Kirov	8,41	admissible
12	Dimitrova	8,36	admissible
13	communist	9,52	admissible
14	Ashkinin	13,99	admissible
15	Eshpaya	4,75	admissible
16	Y. Kyrli	22,79	moderately dangerous
17	K. Liebnecht	44,31	dangerous
18	Park of the XXX Anniversary of the Komsomol	4,92	admissible
19	Plant NP "Iskozh"	12,37	admissible
20	JSC "Marbiopharm"	22,47	moderately dangerous
21	CJSC "Myasokombinat"	5,47	admissible
22	OKTB "Crystal"	11,47	admissible
23	JSC "MMZ"	21,13	moderately dangerous

Despite the heterogeneity of urban soils, the results obtained make it possible to identify the degree of anthropogenic influence on the content of metals in the soils of the city of Yoshkar-Ola. The analysis showed that in the soils of the city the content of lead is 11.5, copper is 19.2, and zinc is 4.5 times higher than in the Pine Grove forest park. In general, it should be noted that in the studied soils of the city of Yoshkar-Ola, no significant excesses of the MPC for the gross content of heavy metals were found, however, there is still a rather high level of HM content along highways and in the industrial part of the city.

When studying the contamination of urban soils with radionuclides (Voskresensky, 2008), it was found that a higher content of 40K, 226Ra, 232Th and 90Sr was observed in anthropogenically contaminated areas, this is due to the fact that up to 30% of the territory in the city of Yoshkar-Ola is occupied by soils with the degree of profile disturbance, in the structure of which there are bulk humus layers with a thickness of 18 to 30 cm, as well as buried organo-mineral (sometimes peat) horizons. It is known that the levels of radionuclides in soils are largely determined by their content in soil-forming rocks. In general, the content of radionuclides in the soils of the city of Yoshkar-Ola can be classified as insignificant; a higher level of contamination of urban soils with radioactive elements is associated with anthropogenic activities. In general, soil contamination with the main dose-forming radionuclides does not cause concern, the average value for the city of Yoshkar-Ola is much lower than for Russia (State report ..., 2007, 2008, 2009).

Thus, the soils of Yoshkar-Ola have a low level of pollution, which indicates that, despite the high anthropogenic load, urban soils have retained the ability to self-purify. In addition, soil pollution with salts of heavy metals is not an urgent problem, since there are no chemical, metallurgical, petrochemical and other enterprises in the city that are sources of air and soil pollution.

The soil directly affects the habitat and quality of life of the population. Therefore, the problems of collection, storage, removal and disposal of production and consumption waste, improvement and sanitary maintenance of populated areas continue to be one of the priority areas in ensuring the sanitary and epidemiological well-being of a person.

Recycling. Waste is understood as the remains of raw materials and semi-finished products formed in the process of manufacturing products and which have completely or partially lost the consumer properties of the source material; products of physical and chemical processing of raw materials, as well as the extraction and enrichment of minerals, the production of which is not the purpose of the production process in question and which can be used in production as raw materials for processing, fuel, etc. Waste refers to material objects that may have high potential hazard to the environment and public health.

Waste is divided into household (municipal) and industrial (production waste). In turn, household and industrial waste can be divided into two groups: solid (waste of metals, wood, plastics, dust, garbage, etc.) and liquid (sewage sludge, sludge, etc.). Waste according to the degree of possible harmful impact on the environment is divided into extremely hazardous (Class 1), highly hazardous (Class 2), moderately hazardous (Class 3), low hazardous (Class 4) and practically non-hazardous (Class 5). Waste hazard classes are introduced by Federal Law No. 309-FZ of December 30, 2008.

The amount of accumulated garbage on the planet is growing, while for every city dweller there are from 150 to 600 kg of garbage per year. One citizen of the Russian Federation accounts for 300-400 kg/year of household waste (in Moscow - 300-320 kg).

The main unresolved issues in the field of sanitary cleaning of populated areas are: the presence of unauthorized dumps that lead to contamination of soil, groundwater, atmospheric air and are a food base for mouse-like rodents; increase in the accumulation of waste, change in their structure, including those with a long decomposition period; unsatisfactory organization of collection, storage and disposal of garbage. Such problems are most typical for the city of Yoshkar-Ola. Waste collection sites, built mainly 30-40 years ago for the accumulation of up to 1 m3 of waste per inhabitant, are now used at a rate of 1.25 m3. In fact, taking into account large-sized waste, including a complex combined composition in the form of products that have lost their consumer properties (old furniture, household appliances, household appliances, strollers, packaging, home repair waste, etc.), this rate exceeds 1.45 m3, and in the central part of the city is about 2 m3. The opening of a significant number of new retail trade organizations, public catering, public service facilities, and office space continues to exacerbate the problem (Annual Report..., 2010).

Currently, there are several ways to dispose of waste. According to the technological essence, waste disposal methods can be divided into: 1) biothermal (landfills, plowing fields, storage areas, compost fields and a biothermal composting plant); 2) thermal (burning without use, burning waste as an energy fuel, pyrolysis to produce combustible gas and oil-like oils); 3) chemical (hydrolysis); 4) mechanical (compression of waste into building blocks). But the most widely used biothermal and thermal methods. On the territory of Russia, the waste sorting system at landfills is poorly organized.

An analysis of the fractional composition of municipal solid waste (MSW) entering the municipal solid waste landfill in the city of Yoshkar-Ola showed that food waste accounts for 40-42%, paper - 31-33, wood - 4.6-5.0, polymeric materials - 3.5-5.0, textiles - 3.5-4.5, cullet - 2.0-2.5, stones and ceramics - 1.5-2.0, ferrous and non-ferrous metals - 0.5- 0.6, bones - 0.3-0.5, leather and rubber - 0.5-1.0, coal and slag - 0.8-1.5 and screenings - 11.0-20.0% (table .7).

Table 7 - Composition of municipal solid waste in the Russian Federation and Yoshkar-Ola, %
(Ecology of the city of Yoshkar-Ola, 2007)

Landfills for waste disposal. A landfill for waste disposal is a special engineering structure that excludes negative impact on the environment in the process of waste disposal. The project for the organization and construction of the landfill provides for the creation of impervious multilayer screens that prevent the flow of leachate into the soil and aquifers. Along with this, the collection and treatment of leachate is formed at the landfill. The organization and construction of the landfill is carried out in accordance with the legislation in the field of environmental protection and waste management, sanitary-epidemiological and urban planning legislation, as well as in the presence of a positive conclusion of the state expertise on the construction project.

A modern solid waste landfill is a complex of environmental structures designed for centralized collection, neutralization and disposal of solid waste, preventing the ingress of harmful substances into the environment, pollution of the atmosphere, soil, surface and ground water, the spread of rodents, insects and pathogens.

There are two waste disposal facilities in the City of Yoshkar-Ola urban district: one for the disposal of municipal solid waste, and the second for industrial waste. The landfill for municipal solid waste is intended for storage of solid waste, it provides for constant, albeit very long-term processing of waste with the participation of atmospheric oxygen and microorganisms.

The Yoshkar-Ola industrial waste landfill accepts industrial waste of hazard class 3-4 (sludge containing salts of heavy metals, acids, alkalis, etc.) generated during production at industrial enterprises of the city.

According to the Federal Law of 08.08.2001 No. 128-FZ, activities for the collection, use, neutralization, transportation, and disposal of waste of I-IV hazard class are subject to licensing. Activities for the accumulation of waste of hazard class I - V, as well as activities for the collection, use, neutralization, transportation, and disposal of waste of hazard class V are not subject to licensing (as amended by Federal Law No. 309-FZ of December 30, 2008).

The soils and soil cover of the Far East are characterized by great diversity, which is determined by the bioclimatic heterogeneity of the conditions for their formation from the Arctic desert zone in the north to the forest-steppe zone in the south and from the humid ocean coast in the east to continental spaces in the west.

The history of the study of soils in the Far East goes back more than a hundred years, but the modern understanding of soils, soil-forming processes, and the peculiarities of regional soil formation has been developed over the past 50 years. It is reflected in individual publications and monographs by a number of authors. The knowledge of soils and soil cover of various subregions of the Far East is far from unambiguous. The most studied are the soils of the south of the Far East, which is associated with its more active, although not earlier development.

The peculiarity of the nature of the southern half of the Far East, its soils are described in the work of Yu.A. Liverovsky, B.P. Kolesnikov (1949). In special monographic works G.I. Ivanov (1964, 1966, 1976) most fully elucidated the issues of genesis and classification of soils in Primorye. A certain contribution to the study of soils of coniferous-deciduous and broad-leaved forests of the low mountains of Primorye was made by N.A. Kreida (1970), and soils of mountain dark coniferous forests - N.F. Pshenichnikova (1989). In the last decade, works have appeared that expand the understanding of the specifics of soil formation within mountainous (Pshenichnikov and Pshenichnikova, 2002) and lowland areas (Shlyakhov and Kostenkov, 2000) of continental oceanic ecosystems, as well as floodplain soils of southeastern Primorye (Shelest, 2001).

The characteristics of the soils of the Khabarovsk Territory and the Amur Region are most fully reflected in the work of A. T. Terentiev (1969), and later in the monographs of the KhabKNII staff Yu.S. Prozorova (1974), Yu.I. Ershova (1984), A.F. Makhinova (1989).

The soils of the island ecosystems of Sakhalin and the Kuriles are comprehensively presented in two monographs by A.M. Ivleva (1965, 1977).

The soils of the Kamchatka Peninsula have been studied to a much lesser extent. The work of I. A. Sokolov (1973) is still the only most complete source on the relationship between volcanism and soil formation in the Far East.

The territory of the Magadan region is characterized by the least development and, as a result, its soils are the least studied. EAT. Naumov, B.P. Gradusov (1974) was one of the first to generalize the material on the features of taiga soil formation in the Far North-East of Eurasia. Somewhat later, the staff of the Institute of Biological Problems of the North of the Far Eastern Scientific Center of the USSR Academy of Sciences published the work "Geography and Genesis of Soils of the Magadan Region" edited by V. I. Ignatenko (1980).

To date, questions of the genesis and classification of soils in individual parts of the Far East have been developed with varying degrees of detail. It is expedient to generalize and generalize the available material on the soils of the entire Far East. Such an attempt was made by B.F. Pshenichnikov (1986) as part of the textbook "Soils of the Far East".

This textbook discusses the conditions of formation, the morphological structure of soils, the processes of soil formation, the classification and zoning of soils in the Far East region, which, we hope, will help beginners to form an understanding of soils in the Far East.

First, let us briefly dwell on the theoretical issues of soil classification and soil-geographical zoning.

V. V. Dokuchaev was the first to give a scientific definition of soil as an independent natural-historical body of nature (the same as plants, animals, etc.), formed as a result of the simultaneous interaction of soil formation factors: climate, rocks, vegetation and wildlife, relief and age. A certain combination of soil formation factors leads to the formation of a genetic type of soil, accepted by V. V. Dokuchaev as the main classification unit.

According to the classification of soils in force in Russia (Classification and diagnostics of soils of the USSR, 1977), the main taxonomic unit - the genetic type of soils - combines soils with a single profile structure, formed as a result of the development of the same type of soil formation process under conditions with a similar nature of the water-thermal regime, on parent rocks of similar composition and under homogeneous vegetation.

Several dozen types of soils have been identified on the territory of Russia. Some of them are widespread, for example, chernozems, podzolic, brown forest. The latter are zonal soils in the south of the Far East.

Each genetic soil type is successively subdivided into subtypes, genera, species, varieties, and categories.

A soil subtype is a transitional group of soils between types that differ in the manifestation of the main and accompanying processes of soil formation. For example, with the development of the podzolization process in the soil, along with the burozem formation, a subtype of brown forest podzolized soils is formed; the development of the soddy process, along with the podzolic process, leads to the formation of a subtype of soddy-podzolic soil. The appearance of a subtype can also be due to the significant dynamics of the main feature of the type (for example: light gray, gray, dark gray forest soils) or facies features of natural conditions within the soil zone (for example, southern chernozem).

The genus of soils is distinguished within the subtypes and is represented by a group of soils, the qualitative genetic features of which are determined by the composition of the soil absorbing complex and the chemistry of salinization due to a number of local conditions: the composition of parent rocks, the chemistry of groundwater, and the relict features of the soil-forming substrate.

A soil type is a group of soils within a genus that differs in the degree of development of the main soil-forming process. For example, according to the degree of podzolization (weakly, medium, strongly podzolized), humus content (medium, highly humus).

Soil variety - a group of soils within a genus that differs in the granulometric composition of the upper horizons (for example, clayey, loamy, etc.).

Soil discharges are a group of soils of the same type and the same mechanical composition, but developed on parent rocks of different origin and different petrographic composition (for example, on granites, limestones, alluvium).

In order to determine the type affiliation of the soil, it is first of all necessary to determine the type of soil profile based on the study of its morphological structure. How to do this is described in detail in our methodological manual for the first ecological practice (Urusov et al., 2002). Then it is necessary to compare the morphological parameters with the scheme of the morphological structure of various soils. Having determined the type of soil profile, it is necessary to determine the type of geographic landscape, the geographic range of a given soil, the main and accompanying elementary soil-forming processes, and the type of migration and accumulation of substances in a given soil.

In soil diagnostics, first of all, data on the morphological structure of the profile, soil formation conditions, data on the content and nature of intra-profile differentiation of humus, the composition of absorbed bases, as well as intra-profile differentiation of physical clay and sand, silt and bulk chemical composition are used.

Soil-geographic zoning is the allocation of territories that are homogeneous in terms of the structure of the soil cover, similar in terms of soil formation conditions and their possible use in agricultural production.

In 1962, at Moscow State University (Soil-geographic zoning of the USSR, 1962), a scheme of soil-geographic zoning was developed, which is presented below.

Taxonomic system of soil-geographical zoning:

The soil bioclimatic belt is a set of soil zones and vertical soil structures similar in terms of radiation, thermal conditions and the nature of their influence on the development of vegetation, weathering and soil formation. Thermal conditions are the determining factor in the allocation of the belt.

Soil-bioclimatic region This is the area of soil zones and vertical soil structures within the soil-bioclimatic zone, distinguished by the peculiarity of moisture and continentality, and as a result, by specific features of vegetation development, weathering and soil formation. Diagnostic indicators in the allocation of the area are the conditions of moisture and continentality.

The vertical soil structure is the area of a certain number of vertical soil zones, determined by the position of a mountainous country in the system of soil-bioclimatic regions and the main features of the general orography. In terms of its taxonomic position in the zoning system, the vertical soil structure is identical to the soil zone on the plain. The leading indicators in identifying vertical soil structures are thermal conditions, moisture, and the type of soil formation in the lower zone. Soil province - a part of the soil zone, distinguished by the originality of its moisture and continentality, temperature differences, which determine the specifics of soils, soil formation conditions. Vertical soil zone - the area of a certain zonal mountain soil type.

Soil district - a part of a province or a vertical soil zone with a certain genetic type of relief, within which a certain combination of soils and parent rocks can be traced. The significant differences between the districts are due to the peculiarities of the local climate and vegetation cover. A soil region is an area of soils within a soil region with a relatively uniform topography, composition of the soil and vegetation cover, and a certain microrelief.

The specifics of the geographical position of the Far East of Russia (Fig. 2), which crosses three soil-bioclimatic zones from north to south: polar (cold), boreal (moderately cold), subboreal (moderate), determines a wide variety of soil formation conditions and the allocation of the following soil areas within them , zones and provinces.

1http://www.priroda.ru/regions/info/detail.php?SECTION_ID=&FO_ID=440&ID=6452

2http://xn--80aa2bkafhg.xn--p1ai/article.php?nid=12709

3http://www.kmslib.ru/kraevedenie/geografiya

4http://ecology-of.ru/priroda/climat-goroda-khabarovsk

5 https://abc.vvsu.ru/books/u_ekologija/page0002.asp

6 http://samanka.ru/osobennosti-landshaftnogo-dizajna.html

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