Natural zones and their soils table. What are the soils and natural areas. Features of the main types of soils

The content of the article

THE SOIL- the most surface layer of the earth's land, resulting from changes in rocks under the influence of living and dead organisms (vegetation, animals, microorganisms), solar heat and atmospheric precipitation. The soil is a completely special natural formation with only its inherent structure, composition and properties. The most important property of the soil is its fertility, i.e. the ability to ensure the growth and development of plants. To be fertile, the soil must have a sufficient amount of nutrients and a supply of water necessary to feed the plants, it is by its fertility that the soil, as a natural body, differs from all other natural bodies (for example, barren stone), which are not able to provide the need of plants for the simultaneous and the joint presence of two factors of their existence - water and minerals.

Soil is the most important component of all terrestrial biocenoses and the biosphere of the Earth as a whole; numerous ecological connections of all organisms living on earth and in the earth (including humans) with the lithosphere, hydrosphere and atmosphere go through the soil cover of the Earth.

The role of soil in the human economy is enormous. The study of soils is necessary not only for agricultural purposes, but also for the development of forestry, engineering and construction. Knowledge of soil properties is necessary for solving a number of problems in health care, exploration and extraction of minerals, the organization of green zones in the urban economy, environmental monitoring, etc.

Soil Science: History, Relationship with Other Sciences.

The science of the origin and development of soils, the patterns of their distribution, ways of rational use and increasing fertility is called soil science. This science is a branch of natural science and is closely related to the physical and mathematical, chemical, biological, geological and geographical sciences, based on the fundamental laws and research methods developed by them. At the same time, like any other theoretical science, soil science develops on the basis of direct interaction with practice, which checks and uses the revealed patterns and, in turn, stimulates new searches in the field of theoretical knowledge. By now, large applied sections of soil science have been formed for agriculture and forestry, irrigation, construction, transport, prospecting for minerals, health care and environmental protection.

Since the systematic occupation of agriculture, mankind, first empirically, and then using scientific methods, studied the soil. The most ancient attempts to assess various soils are known in China (3 thousand BC) and Ancient Egypt. In ancient Greece, the idea of ​​soil was formed in the process of the development of ancient natural philosophical natural science. During the period of the Roman Empire, a large number of empirical observations of soil properties were accumulated and some agronomic methods of soil cultivation were developed.

The long period of the Middle Ages was characterized by stagnation in the field of natural science, but at the end of it (with the beginning of the decomposition of the feudal system), interest in the study of soils reappeared in connection with the problem of plant nutrition. A number of works of that time reflected the opinion that plants feed on water, creating chemical compounds from water and air, and the soil serves them only as a mechanical support. However, by the end of the 18th century. this theory was replaced by Albrecht Thayer's humus theory, according to which plants can only feed on soil organic matter and water. Thayer was one of the founders of agronomy and the organizer of the first higher agronomic educational institution.

In the first half of the 19th century. the famous German chemist Justus Liebig developed the mineral theory of plant nutrition, according to which plants assimilate minerals from the soil, and only carbon in the form of carbon dioxide from humus. Y. Liebikh believed that each harvest depletes the supply of minerals in the soil, therefore, in order to eliminate this deficiency of elements, it is necessary to apply factory-prepared mineral fertilizers to the soil. The merit of Liebig was the introduction of the use of mineral fertilizers into the practice of agriculture.

The value of nitrogen for soil was studied by the French scientist J. Yu. Boussingo.

By the middle of the 19th century. accumulated extensive material on the study of soils, but these data were scattered, not listed in the system and not generalized. There was not even a single definition of the term soil for all researchers.

The outstanding Russian scientist Vasily Vasilyevich Dokuchaev (1846-1903) became the founder of soil science as an independent natural history science. Dokuchaev was the first to formulate the scientific definition of soil, calling the soil an independent natural-historical body, which is the product of the combined activity of the parent rock, climate, plant and animal organisms, soil age and partly the terrain. All the factors of soil formation that Dokuchaev spoke about were known before him, they were consistently put forward by different scientists, but always as the only determining condition. Dokuchaev was the first to say that the emergence of soil occurs as a result of the combined action of all factors of soil formation. He established a view of the soil as an independent special natural body, equivalent to the concepts of a plant, animal, mineral, etc., which arises, develops, continuously changes in time and space, and with this he laid a solid foundation for a new science.

Dokuchaev established the principle of the structure of the soil profile, developed the idea of ​​the regularity of the spatial distribution of certain types of soils covering the land surface in the form of horizontal or latitudinal zones, established vertical zoning, or zonality, in the distribution of soils, which is understood as the regular replacement of some soils by others as they rise from the foot to the top of the high mountains. He also belongs to the first scientific classification of soils, which was based on the entire set of the most important characteristics and properties of the soil. Dokuchaev's classification was recognized by world science and the names he proposed "black earth", "podzol", "salt marsh", "solonetz" have become international scientific terms. He developed methods for studying the origin and fertility of soils, as well as methods for mapping them, and even in 1899 compiled the first soil map of the northern hemisphere (this map was called the "Scheme of Soil Zones of the Northern Hemisphere").

In addition to Dokuchaev, a great contribution to the development of soil science in our country was made by P.A. Kostychev, V.R. Williams, N.M. Sibirtsev, G.N. Vysotsky, P.S. Kossovich, K.K. Gedroits, K. D. Glinka, S. S. Neustruev, B. B. Polynov, L. I. Prasolov and others.

Thus, the science of soil as an independent natural formation was formed in Russia. Dokuchaev's ideas had a strong influence on the development of soil science in other countries. Many Russian terms have entered the international scientific lexicon (chernozem, podzol, gley, etc.)

Scientists from other countries have also carried out important studies for understanding the processes of soil formation and studying the soils of different territories. They are E.V. Gilgard (USA); E. Ramann, E. Blank, V. I. Kubiena (Germany); A. de Sigmond (Hungary); J. Milne (Great Britain), J. Aubert, R. Menien, J. Durant, N. Leneuf, G. Hérard, F. Duchaufour (France); J. Prescott, S. Stephens (Australia) and many others.

For the development of theoretical concepts and the successful study of the soil cover of our planet, business contacts between different national schools are necessary. In 1924 the International Society of Soil Scientists was organized. For a long time, from 1961 to 1981, a large and complex work was carried out to draw up the Soil Map of the World, in the compilation of which Russian scientists played a large role.

Soil study methods.

One of them is comparatively geographical, based on the simultaneous study of the soils themselves (their morphological characteristics, physical and chemical properties) and the factors of soil formation in different geographical conditions with their subsequent comparison. Nowadays, in soil research, various chemical analyzes, analyzes of physical properties, mineralogical, thermochemical, microbiological and many other analyzes are used. As a result, a definite connection is established in the change in certain soil properties with a change in soil-forming factors. Knowing the patterns of distribution of soil-forming factors, it is possible to create a soil map for a vast territory. It was in this way that Dokuchaev made the first world soil map in 1899, known as the "Schemes of the soil zones of the Northern Hemisphere."

Another method is the stationary research method. consists in the systematic observation of a soil process, which is usually carried out on typical soils with a certain combination of soil-forming factors. Thus, the method of stationary research clarifies and details the method of comparative geographical research. There are two methods for studying soils.

Soil formation.

The process of soil formation.

All rocks covering the surface of the globe, from the very first moments of their formation, under the influence of various processes, began immediately to collapse. The sum of the transformation processes of rocks on the surface of the Earth is called weathering or hypergenesis. The collection of weathering products is called the weathering crust. The process of transforming the original rocks into the weathering crust is extremely complex and includes numerous processes and phenomena. Depending on the nature and causes of the destruction of rocks, physical, chemical and biological weathering is distinguished, which usually boils down to the physical and chemical effects of organisms on rocks.

Weathering (hypergenesis) processes spread to a certain depth, forming a zone of hypergenesis . The lower boundary of this zone is conventionally drawn along the top of the upper horizon of underground (stratal) waters. The lower (and most) part of the hypergenesis zone is occupied by rocks, to one degree or another altered by weathering processes. Here, the newest and ancient weathering crust is distinguished, formed in more ancient geological periods. The surface layer of the hypergenesis zone is the substrate on which the soil is formed. How does the process of soil formation take place?

In the process of weathering (hypergenesis), the original appearance of rocks, as well as their elemental and mineral composition, changed. Initially massive (i.e. dense and hard) rocks gradually turned into a fractured state. Examples of rocks crushed as a result of weathering are grit, sand, and clay. Becoming fragmented, the rocks acquired a number of new properties and features: they became more permeable to water and air, the total surface of their particles increased in them, increasing chemical weathering, new compounds were formed, including easily soluble in water compounds and, finally, mountainous breeds acquired the ability to retain moisture, which is of great importance for providing plants with water.

However, the weathering processes themselves could not lead to the accumulation of plant food elements in the rock, and therefore could not turn the rock into soil. The easily soluble compounds formed as a result of weathering can only be washed out of rocks under the influence of atmospheric precipitation; and such an important biological element as nitrogen, consumed by plants in large quantities, is completely absent in igneous rocks.

Loose and water-absorbing rocks became a favorable environment for the life of bacteria and various plant organisms. Gradually, the upper layer of the weathering crust was enriched with the products of the vital activity of organisms and their dying off remains. The decomposition of organic substances and the presence of oxygen led to complex chemical processes, as a result of which the elements of ash and nitrogen food accumulated in the rock. Thus, the rocks of the surface layer of the weathering crust (they are also called parent, bedrock or parent rocks) became soil. Thus, the composition of the soil includes a mineral component corresponding to the composition of the bedrock, and an organic component.

Therefore, the beginning of the process of soil formation should be considered the moment when vegetation and microorganisms settled on the products of weathering of rocks. From that moment on, the crushed rock became soil, i.e. a qualitatively new body with a number of qualities and properties, the most essential of which is fertility. In this respect, all existing soils on the globe are a natural-historical body, the formation and development of which is associated with the development of all organic life on the earth's surface. Once it was born, the soil-forming process never stopped.

Factors of soil formation.

The development of the soil-forming process is most directly influenced by the natural conditions in which it proceeds, its features and the direction in which this process will develop depend on one or another combination of them.

The most important of these natural conditions, called factors of soil formation, are the following: parent (soil-forming) rocks, vegetation, fauna and microorganisms, climate, terrain and soil age. To these five main factors of soil formation (which were also named by Dokuchaev) are now added by the action of water (soil and ground) and human activity. The biological factor is always of leading importance, while the remaining factors are only the background against which the development of soils in nature takes place, but they have a great influence on the nature and direction of the soil-forming process.

Parent rocks.

All existing soils on Earth originated from rocks, so it is obvious that they are most directly involved in the process of soil formation. The chemical composition of the rock is of the greatest importance, since the mineral part of any soil contains, basically, those elements that were part of the parent rock. The physical properties of the parent rock are also of great importance, since factors such as the granulometric composition of the rock, its density, porosity, and thermal conductivity directly affect not only the intensity, but also the nature of the ongoing soil-forming processes.

Climate.

The climate plays a huge role in the processes of soil formation, its influence is very diverse. The main meteorological elements that determine the nature and characteristics of climatic conditions are temperature and precipitation. The annual amount of incoming heat and moisture, the peculiarities of their daily and seasonal distribution, determine completely certain processes of soil formation. The climate affects the nature of the weathering of rocks, affects the thermal and water regimes of the soil. The movement of air masses (wind) affects the gas exchange of the soil and captures small particles of soil in the form of dust. But the climate affects the soil not only directly, but also indirectly, since the existence of one or another vegetation, the habitat of certain animals, as well as the intensity of microbiological activity is determined precisely by climatic conditions.

Vegetation, animals and microorganisms.

Vegetation.

The importance of vegetation in soil formation is extremely great and diverse. Penetrating the upper layer of the parent rock with the roots, the plants extract nutrients from its lower horizons and fix them in the synthesized organic matter. After the mineralization of dead plant parts, the ash elements contained in them are deposited in the upper horizon of the parent rock, thereby creating favorable conditions for the nutrition of the next generations of plants. So, as a result of the constant creation and destruction of organic matter in the upper horizons of the soil, the most important property for it is acquired - the accumulation, or concentration of elements of ash and nitrogen food for plants. This phenomenon is called the biological absorption capacity of the soil.

Due to the decomposition of plant residues, humus accumulates in the soil, which is of great importance in soil fertility. Plant residues in the soil are a necessary nutrient substrate and an essential condition for the development of many soil microorganisms.

In the process of decomposition of soil organic matter, acids are released, which, acting on the parent rock, enhance its weathering.

Plants themselves, in the process of their vital activity, secrete various weak acids with their roots, under the influence of which hardly soluble mineral compounds partially pass into a soluble form, and therefore into a form assimilated by plants.

In addition, the vegetation cover significantly changes the microclimatic conditions. For example, in the forest, compared to treeless areas, the summer temperature is lower, the humidity of the air and soil is increased, the wind force and evaporation of water above the soil are reduced, more snow, melt and rainwater accumulates - all this inevitably affects the soil-forming process.

Microorganisms.

Thanks to the activity of microorganisms inhabiting the soil, organic residues are decomposed and the elements contained in them are synthesized into compounds that are absorbed by plants.

Higher plants and microorganisms form certain complexes, under the influence of which various types of soils are formed. Each plant formation corresponds to a certain type of soil. For example, under the vegetation formation of coniferous forests, chernozem will never form, which is formed under the influence of meadow-steppe vegetation formation.

Animal world.

Animal organisms, of which there are a lot in the soil, are of great importance for soil formation. The most important are invertebrates living in the upper soil horizons and in plant debris on the surface. In the course of their life, they significantly accelerate the decomposition of organic matter and often produce very profound changes in the chemical and physical properties of the soil. Burrowing animals such as moles, mice, ground squirrels, marmots, etc. play an important role. Repeatedly digging through the soil, they contribute to the mixing of organic substances with mineral substances, as well as to increase the water and air permeability of the soil, which enhances and accelerates the decomposition of organic residues in the soil ... They also enrich the soil mass with the products of their vital activity.

Vegetation serves as food for various herbivores, therefore, before entering the soil, a significant part of organic residues undergoes significant processing in the digestive organs of animals.

Relief

has an indirect effect on the formation of the soil cover. Its role is mainly reduced to the redistribution of heat and moisture. A significant change in the height of the terrain entails significant changes in temperature conditions (it gets colder with height). This is associated with the phenomenon of vertical zoning in the mountains. Relatively small changes in altitude affect the redistribution of atmospheric precipitation: low areas, hollows and depressions are always moistened to a greater extent than slopes and rises. The exposure of the slope determines the amount of solar energy coming to the surface: the southern slopes receive more light and heat than the northern ones. Thus, the features of the relief change the nature of the impact of climate on the process of soil formation. Obviously, in different microclimatic conditions, the processes of soil formation will proceed in different ways. Of great importance in the formation of the soil cover is the systematic washout and redistribution of fine earth particles by atmospheric precipitation and melt water over the relief elements. The significance of the relief in conditions of abundant precipitation is great: areas devoid of natural runoff of excess moisture are very often subject to waterlogging.

Soil age.

Soil is a natural body that is in constant development, and the kind that all soils existing on Earth have today is only one of the stages in a long and continuous chain of their development, and individual present soil formations, in the past, represented other forms and in the future may undergo significant transformations even without abrupt changes in external conditions.

There are absolute and relative soil ages. The absolute age of soils is called the period of time elapsed from the moment the soil was formed to the present stage of its development. The soil arose when the parent rock came to the surface and began to undergo soil formation processes. For example, in Northern Europe, the process of modern soil formation began to develop after the end of the last ice age.

However, within the limits of different parts of the land, which were simultaneously freed from the water or ice cover, the soil will not always go through the same stage of its development at every given moment. The reason for this may be differences in the composition of the parent rocks, in the relief, vegetation, and other local conditions. The difference in the stages of soil development in one common area, which has the same absolute age, is called the relative soil age.

The development time of a mature soil profile for different conditions is from several hundred to several thousand years. The age of the territory in general and the soil in particular, as well as changes in the conditions of soil formation in the process of their development, have a significant impact on the structure, properties and composition of the soil. Under similar geographic conditions of soil formation, soils with different ages and developmental histories can differ significantly and belong to different classification groups.

The age of soils is therefore one of the most important factors that must be taken into account when studying a particular soil.

Soil and ground waters.

Water is the environment in which numerous chemical and biological processes take place in the soil. Where groundwater is shallow, it has a strong effect on soil formation. Under their influence, the water and air regimes of soils change. Groundwater enriches the soil with chemical compounds that they contain, sometimes causing salinization. Waterlogged soils contain an insufficient amount of oxygen, which causes the suppression of the activity of some groups of microorganisms.

Human economic activity affects some factors of soil formation, for example, on vegetation (deforestation, replacing it with herbaceous phytocenoses, etc.), and directly on the soil by mechanical processing, irrigation, application of mineral and organic fertilizers, etc. As a result, often soil-forming the processes and properties of the soil change. In connection with the intensification of agriculture, the influence of man on soil processes is constantly increasing.

The impact of human society on the soil is one of the aspects of the overall human impact on the environment. Nowadays, the problem of destruction of the soil cover as a result of improper agricultural soil cultivation and human construction activities is especially acute. The second most important problem is soil pollution caused by chemicalization of agriculture and industrial and household emissions into the environment.

All factors do not influence in isolation, but in close interconnection and interaction with each other. Each of them affects not only the soil, but also each other. In addition, the soil itself in the process of development has a certain effect on all factors of soil formation, causing certain changes in each of them. So, due to the inseparable connection between vegetation and soils, any change in vegetation is inevitably accompanied by a change in soils, and, conversely, a change in soils, in particular, their moisture regime, aeration, salt regime, etc. inevitably entails a change in vegetation.

Soil composition.

Soil consists of solid, liquid, gaseous and living parts. Their ratio is not the same not only in different soils, but also in different horizons of the same soil. Naturally, a decrease in the content of organic substances and living organisms from the upper soil horizons to the lower ones and an increase in the intensity of transformation of the components of the parent rock from the lower horizons to the upper ones.

The solid part of the soil is dominated by mineral substances of lithogenic origin. These are fragments and particles of primary minerals of various sizes (quartz, feldspars, hornblendes, mica, etc.), formed in the process of weathering of secondary minerals (hydromica, montmorillonite, kaolinite, etc.) and rocks. The sizes of these fragments and particles are varied - from 0.0001 mm to several tens of cm. This variety of sizes determines the looseness of the soil structure. The bulk of the soil is usually fine earth - particles with a diameter of less than 1 mm.

The mineralogical composition of the solid part of the soil largely determines its fertility. The composition of mineral substances includes: Si, Al, Fe, K, Mg, Ca, C, N, P, S, much less trace elements: Cu, Mo, I, B, F, Pb, etc. The vast majority of elements are in oxidized form. In many soils, mainly in soils of insufficiently moistened territories, there is a significant amount of calcium carbonate CaCO 3 (especially if the soil was formed on a carbonate rock), in soils of arid regions - CaSO 4 and other more readily soluble salts (chlorites); the soils of humid tropical regions are enriched in Fe and Al. However, the implementation of these general laws depends on the composition of the parent rocks, soil age, topography, climate, etc.

The composition of the solid part of the soil also includes organic matter. There are two groups of organic substances in the soil: those that have entered the soil in the form of plant and animal residues and new, specific humic substances arising from the transformation of these residues. There are gradual transitions between these groups of soil organic matter, in accordance with this, the organic compounds contained in the soil are also divided into two groups.

The first group includes compounds contained in large quantities in plant and animal residues, as well as compounds that are products of the vital activity of plants, animals and microorganisms. These are proteins, carbohydrates, organic acids, fats, lignin, resins, etc. These compounds together account for only 10-15% of the total mass of soil organic matter.

The second group of soil organic compounds is represented by a complex complex of humic substances, or humus, which arose as a result of complex biochemical reactions from compounds of the first group. Humic substances make up 85–90% of the organic part of the soil, they are represented by complex high-molecular compounds of an acidic nature. The main groups of humic substances are humic acids and fulvic acids. . In the elemental composition of humic substances, carbon, oxygen, hydrogen, nitrogen and phosphorus play an important role. The humus contains the main elements of plant nutrition, which, under the influence of microorganisms, become available to plants. The humus content in the upper horizon of different soil types varies widely: from 1% in gray-brown desert soils to 12-15% in chernozems. Different types of soils differ in the nature of the change in the amount of humus with depth.

The soil also contains intermediate decomposition products of organic compounds of the first group.

When organic matter decomposes in the soil, the nitrogen contained in them is converted into forms available to plants. Under natural conditions, they are the main source of nitrogen nutrition for plant organisms. Many organic substances are involved in the creation of organo-mineral structural units (lumps). The resulting structure of the soil largely determines its physical properties, as well as water, air and thermal conditions.

The liquid part of the soil or, as it is also called, the soil solution Is water contained in the soil with gases, mineral and organic substances dissolved in it, which got into it when passing through the atmosphere and percolating through the soil mass. The composition of soil moisture is determined by the processes of soil formation, vegetation, general characteristics of the climate, as well as the season, weather, human activities (fertilization, etc.).

Soil solution plays a huge role in soil formation and plant nutrition. The main chemical and biological processes in the soil can only take place in the presence of free water. Soil water is the environment in which the migration of chemical elements occurs in the process of soil formation, the supply of plants with water and dissolved nutrients.

In non-saline soils, the concentration of substances in the soil solution is low (usually does not exceed 0.1%), and in saline soils (salt marshes and solonetzes) it is sharply increased (up to as many as tens of percent). The high content of substances in soil moisture is harmful to plants, because this makes it difficult for them to receive water and nutrients, causing physiological dryness.

The reaction of the soil solution in soils of different types is not the same: acidic reaction (pH 7) - soda salt licks, neutral or slightly alkaline (pH = 7) - ordinary chernozems, meadow and brown soils. Too acidic and too alkaline soil solution negatively affects the growth and development of plants.

The gaseous part, or soil air, fills the pores of the soil that are not occupied by water. The total volume of soil pores (porosity) is from 25 to 60% of the soil volume ( cm... Morphological characteristics of soils). The ratio between soil air and water is determined by the degree of soil moisture.

The composition of soil air, which includes N 2, O 2, CO 2, volatile organic compounds, water vapor, etc., differs significantly from the atmosphere and is determined by the nature of many chemical, biochemical, and biological processes occurring in the soil. The composition of soil air is not constant, depending on external conditions and the season, it can change significantly. For example, the amount of carbon dioxide (CO 2) in the soil air changes significantly in the annual and daily cycles due to the different rates of gas emission by microorganisms and plant roots.

Constant gas exchange takes place between soil and atmospheric air. Root systems of higher plants and aerobic microorganisms vigorously absorb oxygen and release carbon dioxide. Excess CO 2 from the soil is released into the atmosphere, and atmospheric air enriched with oxygen penetrates into the soil. Gas exchange of the soil with the atmosphere can be hindered either by the dense composition of the soil or by its excessive moisture. In this case, the oxygen content in the soil air sharply decreases, and anaerobic microbiological processes begin to develop, leading to the formation of methane, hydrogen sulfide, ammonia and some other gases.

Oxygen in the soil is necessary for the respiration of plant roots, therefore, the normal development of plants is possible only under conditions of sufficient air access to the soil. With insufficient oxygen penetration into the soil, plants are inhibited, slow down their growth, and sometimes even completely die.

Oxygen in the soil is also of great importance for the life of soil microorganisms, most of which are aerobes. In the absence of air access, the activity of aerobic bacteria stops, and in this regard, the formation of nutrients necessary for plants in the soil also stops. In addition, under anaerobic conditions, processes occur that lead to the accumulation of compounds harmful to plants in the soil.

Sometimes, some gases may be present in the soil air, penetrating through the strata of rocks from places of their accumulation; this is the basis for special gas geochemical methods of prospecting for mineral deposits.

The living part of the soil consists of soil microorganisms and soil animals. The active role of living organisms in the formation of soil determines its belonging to bioinert natural bodies - the most important components of the biosphere.

Water and thermal regimes of the soil.

The water regime of the soil is a combination of all the phenomena that determine the intake, movement, consumption and use of soil moisture by plants. Soil water regime – the most important factor in soil formation and soil fertility.

Precipitation is the main source of soil water. A certain amount of water enters the soil as a result of condensation of steam from the air, sometimes nearby groundwater plays a significant role. In areas of irrigated agriculture, irrigation is of great importance.

Water consumption is as follows. Part of the water entering the soil surface flows down as surface runoff. The largest amount of moisture that has entered the soil is absorbed by plants, which then partially evaporate it. Some water is consumed for evaporation , moreover, part of this moisture is retained by the vegetation cover and evaporates from its surface into the atmosphere, and part evaporates directly from the soil surface. Soil water can also be consumed in the form of subsurface runoff - a temporarily existing phenomenon that occurs during periods of seasonal soil moisture. At this time, gravity water begins to move along the most permeable soil horizon, the aquiclude for which is the less permeable horizon. Such seasonally existing waters are called Finally, a significant part of the soil water can reach the surface of the groundwater, the outflow of which occurs through a waterproof bed-water confinement, and leave as part of the groundwater runoff.

Atmospheric precipitation, melt and irrigation water penetrate into the soil due to its permeability (ability to pass water). The more large (non-capillary) intervals in the soil, the higher its water permeability. Of particular importance is water permeability for the absorption of melt water. If in the fall the soil is frozen in a highly moistened state, then usually its permeability to water is extremely insignificant. Under forest vegetation, which protects the soil from severe freezing, or in fields with early snow retention, melt water is well absorbed.

Technological processes during soil cultivation, the supply of water to plants, physicochemical and microbiological processes that determine the transformation of nutrients in the soil and their supply with water to the plant depend on the water content in the soil. Therefore, one of the main tasks of agriculture is to create a water regime in the soil that is favorable for cultivated plants, which is achieved by the accumulation, conservation, rational use of soil moisture, and, if necessary, by irrigation or drainage of land.

The water regime of the soil depends on the properties of the soil itself, climate and weather conditions, the nature of natural plant formations, on cultivated soils - on the characteristics of cultivated plants and their cultivation technique.

The following main types of soil water regime are distinguished: leaching, non-leaching, effusion, stagnant and permafrost (cryogenic).

Pririmyvny In the type of water regime, the entire soil layer is annually soaked to groundwater, while the soil returns to the atmosphere less moisture than it receives (excess moisture seeps into the groundwater). Under the conditions of this regime, the soil-subsoil stratum is, as it were, washed out by gravitational water every year. The flushed type of water regime is typical for humid temperate and tropical climates, where the amount of precipitation is greater than evaporation.

The non-flushing type of water regime is characterized by the absence of continuous soaking of the soil mass. Atmospheric moisture penetrates into the soil to a depth of several decimeters to several meters (usually no more than 4 m), and between the wetted soil layer and the upper boundary of the capillary border of groundwater there is a horizon with constant low moisture (close to wilting moisture), called the dead horizon of desiccation ... This mode differs in that the amount of moisture returned to the atmosphere is approximately equal to its intake with precipitation. This type of water regime is typical for a dry climate, where the amount of precipitation is always significantly less than evaporation (a conventional value characterizing the maximum possible evaporation in a given area with an unlimited supply of water). For example, it is typical for steppes and semi-deserts.

Effusion the type of water regime is observed in a dry climate with a sharp predominance of evaporation over precipitation, in soils that feed not only on precipitation, but also on the moisture of shallow groundwater. With an effusion-type water regime, groundwater reaches the soil surface and evaporates, which often leads to land salinization.

The stagnant type of water regime is formed under the influence of the close occurrence of groundwater in a humid climate, in which the amount of atmospheric precipitation exceeds the amount of evaporation and absorption of water by plants. Due to excessive moisture, a perch is formed, as a result of which waterlogging of the soil occurs. This type of water regime is typical for depressions in the relief.

Permafrost (cryogenic) type of water regime is formed on the territory of continuous permafrost. Its peculiarity is the presence at a shallow depth of a constantly frozen water-resistant horizon. As a result, despite the small amount of precipitation, the soil is oversaturated with water in the warm season.

The thermal regime of the soil is the sum of the phenomena of heat exchange in the system of the surface layer of air - soil - parent rock; its characteristics also include the processes of transfer and accumulation of heat in the soil.

The main source of heat entering the soil is solar radiation. The thermal regime of the soil is determined mainly by the ratio between the absorbed solar radiation and the thermal radiation of the soil. The features of this ratio determine the differences in the regime of different soils. The thermal regime of the soil is formed mainly under the influence of climatic conditions, however, it is also influenced by the thermophysical properties of the soil and its underlying rocks (for example, the intensity of absorption of solar energy depends on the color of the soil, the darker the soil, the greater the amount of solar radiation it absorbs) ... Permafrost has a special effect on the thermal regime of the soil.

The thermal energy of the soil is involved in the phase transitions of soil moisture, being released during ice formation and condensation of soil moisture and wasted during ice melting and evaporation.

The thermal regime of the soil has a secular, long-term, annual and daily cyclicality associated with the cyclicity of the solar radiation energy entering the earth's surface. On average, long-term terms, the annual heat balance of a given soil is equal to zero.

Daily fluctuations in soil temperature cover the soil thickness from 20 cm to 1 m, annual - up to 10-20 m. Soil freezing depends on the climatic characteristics of the site, the freezing point of the soil solution, the thickness of cooling the soil). The depth of soil freezing rarely exceeds 1–2 m.

Vegetation has a significant effect on the thermal regime of the soil. It traps solar radiation, as a result of which the soil temperature in summer can be lower than the air temperature. Forest vegetation has a particularly noticeable effect on the thermal regime of soils.

The thermal regime of the soil largely determines the intensity of mechanical, geochemical and biological processes in the soil. For example, the intensity of the biochemical activity of bacteria increases with an increase in soil temperature to 40–50 ° C; above this temperature, the vital activity of microorganisms is inhibited. At temperatures below 0 ° C, biological phenomena are abruptly inhibited and stopped. The thermal regime of the soil has a direct impact on the growth and development of plants. An important indicator of the provision of plants with soil heat is the sum of active soil temperatures (i.e. temperatures above 10 ° C, at these temperatures active vegetation of plants takes place) at a depth of the arable layer (20 cm).

Morphological characteristics of soils.

Like any natural body, the soil has a sum of external, so-called morphological features, which are the result of the processes of its formation and therefore reflect the origin (genesis) of soils, the history of their development, their physical and chemical properties. The main morphological features of the soil are: soil profile, color and color of soils, soil structure, granulometric (mechanical) composition of soils, composition of soils, new formations and inclusions.

Soil classification.

Each science, as a rule, has a classification of the object of its study, and this classification reflects the level of development of science. Since science is developing all the time, the classification is being improved accordingly.

In the pre-dokuchaev period, they studied not the soil (in the modern view), but only its individual properties and aspects, therefore, the soil was classified according to its individual properties - chemical composition, granulometric composition, etc.

Dokuchaev showed that the soil is a special natural body, which is formed as a result of the interaction of soil formation factors, and established the characteristic features of soil morphology (first of all, the structure of the soil profile) - this gave him the opportunity to develop a soil classification on a completely different basis than was done previously.

Dokuchaev took genetic soil types formed by a certain combination of soil formation factors as the main classification unit. This genetic classification of soils is based on the structure of the soil profile, which reflects the process of soil development and their regimes. The modern soil classification used in our country is a developed and supplemented classification by Dokuchaev.

Dokuchaev identified 10 soil types, and in the updated modern classifications there are more than 100 of them.

According to the modern classification used in Russia, soils with a single profile structure, with a qualitatively similar process of soil formation, which develops under conditions of the same thermal and water regimes, on parent rocks of a similar composition and under the same type of vegetation, are combined into one genetic type. Depending on the moisture content, the soils are combined into rows. Rows of automorphic soils are distinguished (i.e., soils that receive moisture only due to atmospheric precipitation and on which groundwater does not have a significant effect), hydromorphic soils (i.e. soils that are significantly affected by groundwater) and transitional automorphic soils. -hydromorphic soils.

Genetic soil types are subdivided into subtypes, genera, species, varieties, categories, and they are combined into classes, series, formations, generations, families, associations, etc.

The genetic classification of soils developed in Russia for the First International Soil Congress (1927) was adopted by all national schools and contributed to the elucidation of the main laws of soil geography.

Currently, a unified international soil classification has not been developed. A significant number of national soil classifications have been created, some of them (Russia, USA, France) include all the soils of the world.

The second approach to soil classification was developed in 1960 in the United States. The American classification is not based on an assessment of the conditions of formation and the associated genetic characteristics of various soil types, but on the basis of easily detectable morphological characteristics of soils, primarily on the study of certain horizons of the soil profile. These horizons were called diagnostic .

The diagnostic approach to soil taxonomy turned out to be very convenient for compiling detailed large-scale maps of small territories, however, such maps practically could not be compared with survey small-scale maps built on the basis of the principle of geographic and genetic classification.

Meanwhile, by the early 1960s, it became clear that a global soil map was needed to define a strategy for agricultural food production, the legend of which should be based on a classification that eliminated the gap between large and small-scale maps.

Experts from the United Nations Food and Agriculture Organization (FAO), together with the United Nations Educational, Scientific and Cultural Organization (UNESCO), have begun to create an International Soil Map of the World. Work on the map lasted more than 20 years and more than 300 soil scientists from different countries took part in it. The map was created through discussions and agreements between various national scientific schools. As a result, a map legend was developed, which was based on a diagnostic approach to the definition of classification units of all levels, although it also took into account certain elements of the geographic-genetic approach. The publication of all 19 sheets of the map was completed in 1981, since then new data have been obtained, certain concepts and formulations in the map legend have been clarified.

Basic laws of soil geography.

The study of the regularities of the spatial distribution of different types of soils is one of the fundamental problems of earth sciences.

Revealing the regularities of soil geography became possible only on the basis of V.V. Dokuchaev's concept of soil as a result of the interaction of soil formation factors, i.e. from the standpoint of genetic soil science. The following basic patterns were identified:

Horizontal soil zoning. In large flat areas, soil types arising under the influence of soil formation conditions typical for a given climate (i.e., automorphic soil types developing on watersheds, provided that atmospheric precipitation is the main source of moisture), are located in vast stripes - zones elongated along strips with close atmospheric moisture (in areas with insufficient moisture) and with the same annual sum of temperatures (in areas with sufficient and excessive moisture). Dokuchaev called these types of soils zonal.

This creates the main regularity of the spatial distribution of soils in flat areas - horizontal soil zoning. Horizontal soil zoning does not have a planetary distribution; it is typical only for very extensive flat areas, for example, the East European Plain, parts of Africa, the northern half of North America, Western Siberia, and the flat areas of Kazakhstan and Central Asia. As a rule, these horizontal soil zones are located latitudinal (i.e., extended along the parallels), but in some cases the direction of the horizontal zones changes sharply under the influence of the relief. For example, the soil zones of western Australia and the southern half of North America stretch along the meridians.

The discovery of horizontal soil zoning was made by Dokuchaev based on the theory of soil formation factors. This was an important scientific discovery, on the basis of which the doctrine of natural zones was created. .

The following main natural zones replace each other from the poles to the equator: polar zone (or zone of arctic and Antarctic deserts), tundra zone, forest-tundra zone, taiga zone, mixed forest zone, deciduous forest zone, forest-steppe zone, steppe zone, semi-desert zone, zone deserts, a zone of savannas and woodlands, a zone of variable wet (including monsoon) forests and a zone of moist evergreen forests. Each of these natural zones is characterized by completely specific types of automorphic soils. For example, on the East European Plain, latitudinal zones of tundra soils, podzolic soils, gray forest soils, chernozems, chestnut soils, and brown desert-steppe soils are clearly expressed.

Areas of subtypes of zonal soils are also located within zones in parallel stripes, which makes it possible to distinguish soil subzones. So, the zone of chernozems is subdivided into subzones of leached, typical, ordinary and southern chernozems, the zone of chestnut soils - into dark chestnut, chestnut and light chestnut.

However, the manifestation of zoning is characteristic not only of automorphic soils. It was found that certain zones correspond to certain hydromorphic soils (i.e. soils, the formation of which occurs under a significant influence of groundwater). Hydromorphic soils are not azonal, but their zoning is manifested differently than in automorphic soils. Hydromorphic soils develop next to automorphic soils and are geochemically related to them; therefore, the soil zone can be defined as the territory of distribution of a certain type of automorphic soils and hydromorphic soils in geochemical conjugation with them, which occupy a significant area - up to 20-25% of the area of ​​soil zones.

Vertical soil zoning. The second regularity of soil geography is vertical zoning, which manifests itself in the change of soil types from the foot of the mountain system to its peaks. With the height of the terrain it becomes colder, which entails regular changes in climatic conditions, flora and fauna. Soil types change accordingly. In mountains with insufficient moisture, the change in vertical belts is determined by a change in the degree of moisture, as well as the exposure of slopes (the soil cover here acquires an exposure-differentiated character), and in mountains with sufficient and excessive moisture, it is due to a change in temperature conditions.

At first, it was believed that the change of vertical soil zones is completely analogous to the horizontal zonation of soils from the equator to the poles, but later it was found that among mountain soils, along with types common both on plains and in mountains, there are soils formed only in mountainous conditions. landscapes. It was also found that a strict sequence of vertical soil zones (belts) is very rarely observed. Separate vertical soil belts fall out, mix, and sometimes even change places, so it was concluded that the structure of the vertical zones (belts) of a mountainous country is determined by local conditions.

The phenomenon of facies. I.P. Gerasimov and other scientists have found that the manifestation of horizontal zoning is corrected by the conditions of specific regions. Depending on the influence of oceanic basins, continental spaces, large mountain barriers on the path of air masses movement, local (facies) climatic features are formed. This is manifested in the formation of the peculiarities of local soils up to the appearance of special types, as well as in the complication of horizontal soil zoning. Due to the phenomenon of facies, even within the distribution of one soil type of soil, there may be significant differences.

Intrazonal soil subdivisions are called soil provinces . A soil province is understood as a part of a soil zone that is distinguished by the specific features of soil subtypes and types and by the conditions of soil formation. Similar provinces of several zones and subzones are combined into facies.

Mosaicity of the soil cover. In the process of detailed soil-survey and soil-cartographic work, it was found that the idea of ​​the homogeneity of the soil cover, i.e. the existence of soil zones, subzones, and provinces is very conditional and corresponds only to the small-scale level of soil research. In fact, under the influence of meso- and micro-relief, variability of the composition of soil-forming rocks and vegetation, and the depth of groundwater, the soil cover within zones, subzones and provinces is a complex mosaic. This soil mosaic consists of different degrees of genetically related soil areas, which form a certain pattern of the soil cover and create its structure, all the components of which can only be shown on large-scale or detailed soil maps.

Natalia Novoselova

Literature:

Williams V.R. Soil science, 1949
Soils of the USSR... M., Thought, 1979
Glazovskaya M.A., Gennadiev A.N. , M., Moscow State University, 1995
Maksakovsky V.P. Geographic picture of the world... Part I. General characteristics of the world. Yaroslavl, Verkhne-Volzhsky book publishing house, 1995
Workshop on General Soil Science... Moscow State University Publishing House, Moscow, 1995
Dobrovolsky V.V. Soil geography with the basics of soil science... M., Vlados, 2001
Zavarzin G.A. Lectures on natural history microbiology... M., Science, 2003
Eastern European forests. Holocene history and modern times... Book 1. Moscow, Nauka, 2004



Soils are classified by type. The first scientist to classify soils was. The following types of soils are found on the territory of the Russian Federation: Podzolic soils, gley soils, arctic soils, permafrost taiga, gray and brown forest soils, and chestnut soils.

Tundra gley the soils are on. Formed without much influence on them. These soils are found in areas where they are (in the Northern Hemisphere). Gley soils are often places where deer live and feed in summer and winter. An example of tundra soils in Russia is, and in the world - this is Alaska in the United States. On the territory with such soils, people are engaged in agriculture. This land grows potatoes, vegetables and various herbs. To improve the fertility of tundra gley soils, the following types of work are used: the most saturated with moisture and irrigation of arid regions. Also, the methods of improving the fertility of these soils include the introduction of organic and fertilizers into them.

Arctic soils are obtained by thawing. Such soil is rather thin. The maximum layer of humus (fertile layer) is 1-2 cm. This type of soil has a low acidic environment. This soil is not restored because of the harshness. These soils are distributed on the territory of Russia only in (on a number of islands). Due to the harsh climate and a small layer of humus, nothing grows on such soils.

Podzolic soils common in forests. There is only 1-4% humus in the soil. Podzolic soils are obtained through the process of podzol formation. A reaction with acid takes place. That is why this type of soil is also called sour. Dokuchaev was the first to describe podzolic soils. In Russia, podzolic soils are common in Siberia and on. In the world, there are podzolic soils in, and Canada. Such soils must be properly processed. They need to be fertilized, organic and mineral fertilizers applied to them. Such soils are more useful in logging than in agriculture. After all, trees grow on them better than agricultural crops. Sod-podzolic soils are a subtype of podzolic soils. In composition, they are in many ways similar to podzolic soils. A characteristic feature of these soils is that they can be washed out more slowly with water, in contrast to podzolic soils. Sod-podzolic soils are found mainly in (the territory of Siberia). This soil contains up to 10% of the fertile layer on the surface, and at depth the layer sharply decreases to 0.5%.

Permafrost taiga soils were formed in forests, under eternal conditions. They are found only in a continental climate. The deepest depths of these soils do not exceed 1 meter. This is caused by the proximity to the permafrost surface. The humus content is only 3-10%. As a subspecies, there are mountain permafrost taiga soils. They form in the taiga, which are covered with ice only in winter. These soils exist. They meet on. More often, mountain permafrost-taiga soils are found next to small water bodies. Outside of Russia, there are such soils in and in Alaska.

Gray forest soils are formed on the territory of forests. An indispensable condition for the formation of such soils is the presence of a continental climate. Deciduous forests and grassy vegetation. Places of formation contain an element necessary for such a soil - calcium. Thanks to this element, water does not penetrate deep into the soil and does not erode them. These soils are gray in color. The humus content in gray forest soils is 2-8 percent, that is, the soil fertility is average. Gray forest soils are divided into gray, light gray, and dark gray. These soils prevail in Russia in the territory from to. Fruit and grain crops are grown on the soil.

Brown forest soils distributed in forests: mixed, coniferous and broad-leaved. These soils exist only under conditions. The color of the soil is brown. Usually brown soils look like this: on the surface of the earth there is a layer of fallen leaves, about 5 cm high. Next comes the fertile layer, which is 20, and sometimes 30 cm. Even lower is a clay layer of 15-40 cm. There are several subtypes of brown soils. The subtypes vary with temperatures. Allocate: typical, podzolized, gley (superficial and pseudopodzolic). On the territory of the Russian Federation, soils are common in the Far East and at the foothills. On these soils, unpretentious crops are grown, for example, tea, grapes and tobacco. It grows well on such soils.

Chestnut soils distributed in and. The fertile layer of such soils is 1.5-4.5%. That says the average soil fertility. This soil has a chestnut, light chestnut and dark chestnut color. Accordingly, there are three subtypes of chestnut soil, differing in color. On light chestnut soils, farming is possible only with abundant watering. The main purpose of this land is pasture. The following crops grow well on dark chestnut soils without watering: wheat, barley, oats, sunflower, millet. There are slight differences in the soil and in the chemical composition of the chestnut soil. Its division into clayey, sandy, sandy loam, light loamy, medium loamy and heavy loamy. Each of them has a slightly different chemical composition. The chemical composition of the chestnut soil is varied. The soil contains magnesium, calcium, water-soluble salts. Chestnut soil tends to recover quickly. Its thickness is supported by the annually falling grass and leaves of trees rare in the steppe. You can get good yields on it, provided there is a lot of moisture. After all, the steppes are usually arid. Chestnut soils in Russia are widespread in the Caucasus, on

Natural zones, replacing each other from the poles to the equator, differ in soil types.

Polar zone (zone of arctic deserts). The Arctic land is the islands and narrow sections of the continental coasts of Asia and North America.

The most common type of automorphic soils in the Arctic is arcto-tundra soils. The thickness of the soil profile of these soils is determined by the depth of seasonal thawing of the soil-ground layer, which rarely exceeds 30 cm.In the soils formed under the most favorable conditions, only the vegetative-peaty horizon (A 0) is well expressed and the thin humus horizon (A1) is much worse. ... In arcto-tundra soils, due to excessive atmospheric moisture and a high-lying surface of permafrost, high humidity is constantly maintained during a short season of positive temperatures. Such soils have a weak acidic or neutral reaction (pH from 5.5 to 6.6) and contain 2.5–3% humus. In relatively fast drying areas with a large number of flowering plants, soils are formed with a neutral reaction and an increased humus content (4–6%).

Salt accumulation is characteristic of the landscapes of the arctic deserts. Salt efflorescence is frequent on the soil surface, and in summer, as a result of salt migration, small brackish lakes can form.

Tundra (subarctic) zone. On the territory of Eurasia, this zone occupies a wide strip in the north of the continent, most of it is located beyond the Arctic Circle, however, in the northeast of the continent, tundra landscapes extend much further south, reaching the northeastern part of the coast of the Sea of ​​Okhotsk. In the Western Hemisphere, the tundra zone covers almost all of Alaska and a vast area of ​​northern Canada. Tundra landscapes are also common on the southern coast of Greenland, Iceland, on some islands in the Barents Sea. In some places, tundra landscapes are found in the mountains above the forest border.

Above the surface of permafrost strata, tundra-gley soils are widespread; they are formed under conditions of difficult drainage of soil and groundwater and a lack of oxygen. They, as well as other types of tundra soils, are characterized by the accumulation of weakly decomposed plant residues, due to which a well-defined peaty horizon (At) is located in the upper part of the profile. Below the peaty horizon is a thin (1.5–2 cm) humus horizon ( A 1) brownish brown. Further, there is a gley soil horizon of a specific bluish-gray color, which is formed as a result of recovery processes under conditions of water saturation of the soil layer. The gley horizon extends to the upper surface of the permafrost.

Now, in connection with the active development of the mineral resources of the North, the problem of protecting the nature of the tundra, and, first of all, its soil cover, has arisen. The upper peaty horizon of tundra soils is easily disturbed and takes decades to recover. Traces of vehicles, drilling and construction machines cover the surface of the tundra, contributing to the development of erosion processes. The disturbance of the soil cover causes irreparable damage to the entire unique nature of the tundra. Strict control of economic activity in the tundra is a difficult, but extremely necessary task.

Taiga zone. Taiga forest landscapes form a vast belt in the northern hemisphere, stretching from west to east in Eurasia and North America.

In the absence of permafrost, different types of podzolic soils are formed on well-permeable sandy and sandy loam soil-forming rocks. The profile structure of these soils:

A 0 - forest litter, consisting of needles litter, the remains of trees, shrubs and mosses, which are at different stages of decomposition. The thickness of this horizon is from 2–4 to 6–8 cm. The reaction of the forest litter is strongly acidic (pH = 3.5–4.0). And 2 - eluvial horizon (washout horizon), from which all more or less mobile connections are taken out to the lower horizons. In these soils, this horizon is called podzolic. . Sandy, easily crumbling, due to washing out of a pale gray, almost white color. Despite its small thickness (from 2–4 cm in the north and in the center to 10–15 cm in the south of the taiga zone), this horizon stands out sharply in the soil profile due to its color.

B - a bright brown, coffee or rusty-brown illuvial horizon, in which erosion prevails, i.e. deposition of compounds of those chemical elements and small particles that were washed out from the upper part of the soil layer (mainly from the podzolic horizon). With depth in this horizon, the rusty-brown hue decreases and gradually passes into the parent rock. The thickness is 30–50 cm.

C - parent rock, represented by gray sand, gravel and boulders.

The thickness of the profile of these soils gradually increases from north to south. The soils of the southern taiga have the same structure as the soils of the northern and middle taiga, but the thickness of all horizons is greater.

In Eurasia, podzolic soils are common only in the part of the taiga zone west of the Yenisei. In North America, podzolic soils are common in the southern part of the taiga zone. The territory east of the Yenisei in Eurasia (Central and Eastern Siberia) and the northern part of the taiga zone in North America (northern Canada and Alaska) are characterized by continuous permafrost, as well as features of the vegetation cover. Acid brown taiga soils (podburs) are formed here, sometimes called ferruginous permafrost taiga soils.

From a medico-geographical point of view, the taiga forest zone is not very favorable, since as a result of intensive soil leaching, many chemical elements are lost, including those necessary for the normal development of humans and animals, therefore, conditions for a partial deficiency of a number of chemical elements are created in this zone ( iodine, copper, calcium and etc.)

Mixed forest zone. To the south of the taiga forest zone, there are mixed coniferous-deciduous forests. In North America, these forests are common in the east of the mainland in the Great Lakes region. in Eurasia - on the territory of the East European Plain, where they form a wide zone. Beyond the Urals, they continue far to the east, up to the Amur region, although they do not form a continuous zone.

The mixed forest zone has a rather variegated soil cover. The most typical type of automorphic soils of mixed forests of the East European Plain are sod-podzolic soils – southern variety of podzolic soils. Soils are formed only on loamy soil-forming rocks. Sod-podzolic soils have the same structure of the soil profile as podzolic soils. They differ from podzolic ones in a lesser thickness of the forest litter (2–5 cm), a greater thickness of all horizons, and a more pronounced humus horizon A1, which lies under the forest litter. The appearance of the humus horizon of sod-podzolic soils also differs from the horizon in podzolic soils, in the upper part it contains numerous grass roots, which often form a well-defined sod. Color - gray of various shades, loose constitution. The thickness of the humus horizon is from 5 to 20 cm, the humus content is 2–4%.

In the upper part of the profile, these soils are characterized by an acidic reaction (pH = 4); with depth, the reaction gradually becomes less acidic.

The use of mixed forest soils in agriculture is higher than that of taiga forests. In the southern regions of the European part of Russia 30–45% of the area is plowed up, in the north the share of plowed lands is much less. Agriculture is difficult due to the acidic reaction of these soils, their strong leaching, and in places swampy and boulders. To neutralize excess acidity, the soil is lime. To obtain high yields, large doses of organic and mineral fertilizers are needed.

Deciduous forest zone. In the temperate zone, in warmer conditions (in comparison with taiga and subtaiga mixed forests), broad-leaved forests with rich grass cover are widespread. In North America, the broadleaf forest zone extends in the east of the continent to the south of the mixed forest zone. In Eurasia, these forests do not form a continuous zone, but stretch in discontinuous stripes from Western Europe to the Primorsky Territory of Russia.

Among the soils formed in these landscapes, two types are distinguished:

1. Gray forest soils formed in the inland regions (central regions of Eurasia and North America). In Eurasia, these soils stretch as islands from the western borders of Belarus to Transbaikalia.

The soil-forming rocks are mainly cover loess-like loams.

Profile structure of gray forest soil:

A 0 - forest litter of tree and grass litter, usually of low thickness (3-5 cm);

А 1 - humus horizon of gray or dark gray color, lumpy-powdery structure, containing a large number of grass roots.

А 1 А 2 - humus-eluvial horizon, lighter colored with a lumpy structure.

А 2 В - eluvial-illuvial horizon, grayish-brownish or grayish-brown in color, with a clearly expressed angular-fine-peaked structure.

B - eluvial, dense, brown-brown, with a nutty or prism-nutty well-defined structure. According to the severity of morphological features, it is subdivided into horizons B 1 and B 2.

BC - transitional from illuvial to parent rock differs in less clear structuredness, less dense constitution.

The type of gray forest soils is divided into three subtypes- light gray, gray and dark gray, the names of which are associated with the intensity of the color of the humus horizon.

Gray forest soils are much more fertile than sod-podzolic soils, they are favorable for growing grain, fodder, horticultural and some industrial crops. The main disadvantage is greatly reduced fertility as a result of centuries of their use and significant destruction as a result of erosion.

2. Brown forest soils formed in areas with a mild and humid oceanic climate, in Eurasia - Western Europe, the Carpathians, the Mountainous Crimea, warm and humid regions of the Caucasus and the Primorsky Territory of Russia, In North America - the Atlantic part of the continent.

The profile of brown forest soils is characterized by a poorly differentiated and thin not very dark humus horizon and consists of the following genetic horizons A 0 –A 0 A 1 –A 1 - B t (B t, I, h, f) –BC – C.

A 0 - forest litter of leaf litter, needles and grit residues, with a thickness of 0.5 to 5 cm.

A 0 A 1 - deep-humus humus horizon of dark gray color, loose.

А 1 - humus horizon of dark-brown or gray-brown color, loose-lumpy or lumpy-granular structure, loamy sometimes with inclusions of rubble. The thickness is 10–20 cm.

In t, I, h, f - a metamorphic horizon of brown or brown-brown color, clayey, sometimes compacted, with a lumpy-nutty or granular-nutty structure.

ВС - horizon transitional to the rock.

C - the parent rock is represented by loamy stony-crushed eluvium and eluvial-diluvium of dense rocks and, much less often, fine-earth rocks.

With a large amount of applied fertilizers and rational agricultural technology, these soils give very high yields of various agricultural crops, in particular, the highest yields of grain crops are obtained on these soils. In the southern regions of Germany and France, brown soils are mainly used for vineyards.

Zone of meadow steppes, forest-steppes and meadow-forb steppes. In Eurasia, to the south of the zone of broad-leaved forests, there is a zone of forest-steppe, which is replaced even further south by a zone of steppes. Automorphic soils of landscapes of meadow steppes of the forest-steppe zone and meadow-forb steppes of the steppe zone are called chernozems .

Soil-forming rocks of the territory of chernozems are represented mainly by loess-like deposits (loess is a fine-grained sedimentary rock of light yellow or fawn color).

The most characteristic feature of these soils, which gave rise to their name, is a powerful, well-developed humus horizon of intense black color.

Profile structure of typical chernozems:

A - humus horizon, uniformly dark-colored horizon with granular structure.

AB - humus dark-colored with general russeting downward or non-uniformly colored with alternating dark humous areas and dark brown, gray-brown spots or wedges, granular structure.

B - transitional to the breed, has a predominantly brown uneven color, gradually turning into the color of the parent rock. According to the degree, form of humus content and structure, they can be subdivided into B 1 -B 2.

Accumulation of carbonates is observed in the ВС к horizon and the С к source rock.

Chernozems are famous for their fertility, the areas of their distribution are the main base for the production of many cereals, primarily wheat, as well as a number of valuable industrial crops (sugar beets, sunflowers, corn). The yield on chernozems depends mainly on the water content in the form available to the plant. In our country, the black earth regions were characterized by crop failures caused by droughts.

The second equally important problem of chernozems is soil destruction caused by erosion. On the chernozem soils used for agriculture, special anti-erosion measures are required.

Zone of dry steppes and semi-deserts of the temperate zone. To the south of the steppe zone, there is a semi-desert zone. The southern steppes (they are called dry steppes), bordering on semi-deserts, differ significantly in vegetation cover and soils from the northern steppes. In terms of vegetation and soils, the southern steppes are closer to semi-deserts than to steppes.

In arid and extracontinental conditions of dry steppes and semi-deserts, chestnut and brown desert-steppe soils, respectively, are formed.

In Eurasia chestnut soils occupy a small area in Romania and are more widely represented in the arid central regions of Spain. They stretch in a narrow strip along the coast of the Black and Azov Seas. To the east (in the Lower Volga region, the Western Caspian region), the area of ​​these soils increases. Chestnut soils are very widespread on the territory of Kazakhstan, from where a continuous strip of these soils goes to Mongolia, and then to Eastern China, occupying most of the territory of Mongolia and the central provinces of China. In Central and Eastern Siberia, chestnut soils are found only as islands. The easternmost area of ​​distribution of chestnut soils is the steppes of Southeastern Transbaikalia.

Spreading brown desert-steppe soils more limited - these are mainly semi-desert regions of Kazakhstan.

In North America, chestnut and brown soils are located in the central part of the continent, bordering the black earth zone in the east, and rocky mountains in the west. In the south, the area of ​​distribution of these soils is limited to the Mexican plateau.

Loess-like loams occurring on rocks of different composition, age and origin are the parent rocks.

Profile structure of chestnut and brown soils:

A - humus horizon. In chestnut soils, it is grayish-chestnut in color, saturated with plant roots, a lumpy structure and has a thickness of 15-25 cm. In brown soils, it is brown, with a lumpy fragile structure, about 10-15 cm thick. The humus content in this horizon is from 2 to 5 % in chestnut soils and about 2% in brown soils.

B - brown-brown transitional horizon, compacted, below there are carbonate new formations. The thickness is 20–30 cm.

С - parent rock, represented by loess-like loam of yellowish-brown color in chestnut soils and brownish-fawn in brown soils. In the upper part, there are carbonate new formations. Below 50 cm in brown soils and 1 m in chestnut soils, gypsum neoplasms are found.

Among chestnut soils, there are three subtypes, replacing each other from north to south:

Dark chestnut, having a humus horizon thickness of about 25 cm or more, chestnut with a humus horizon thickness of about 20 cm and light chestnut, with a thickness of the humus horizon of about 15 cm.

A characteristic feature of the soil cover of dry steppes is its extreme variegation, this is due to the redistribution of heat and, especially, moisture, and with it water-soluble compounds, according to the forms of meso- and micro-relief. Lack of moisture is the reason for a very sensitive reaction of vegetation and soil formation even to a slight change in moisture. Zonal automorphic soils (i.e. chestnut and brown desert-steppe soils) occupy only 70% of the territory, the rest falls on saline hydromorphic soils (salt licks, salt marshes, etc.).

Desert zone. In Eurasia, a desert zone stretches south of the semi-desert zone. It is located in the inland part of the continent - on the vast plains of Kazakhstan, Central and Central Asia. Zonal automorphic desert soils are gray-brown desert soils.

Loess-like and ancient alluvial deposits, processed by the wind, prevail among the parent rocks.

Gray-brown soils are formed on elevated flat areas of the relief. A characteristic feature of these soils is the accumulation of carbonates in the upper part of the soil profile, which looks like a surface porous crust.

Profile structure of gray-brown soils:

And to - carbonate horizon, it is a surface crust with characteristic rounded pores, cracked into polygonal elements. The thickness is 3–6 cm.

A - a weakly expressed humus horizon of gray-brown color, in the upper part it is weakly fastened by roots, loose downward, easily fluttering by the wind. The thickness is 10–15 cm.

B - transitional, compacted brown horizon, prism-like-blocky structure, containing rare and poorly expressed carbonate formations. Thickness is from 10 to 15 cm.

C - parent rock - loose loess-like loam overflowing with small crystals of gypsum. At a depth of 1.5 m and below, a kind of gypsum horizon often occurs, represented by clusters of vertically arranged needle-like gypsum crystals. The thickness of the gypsum horizon is from 10 cm to 2 m.

The characteristic hydromorphic soils of deserts are salt marshes , those. soils containing 1% or more water-soluble salts in the upper horizon. Most of the salt marshes are distributed in the desert zone, where they occupy about 10% of the area. In addition to the desert zone, salt marshes are quite widespread in the zone of semi-deserts and steppes, they are formed when the groundwater is close to the ground and the effusion water regime. The salt-containing groundwater reaches the soil surface and evaporates; as a result, salts are deposited in the upper soil horizon and salinization occurs.

Soil salinization can occur in any zone under sufficiently arid conditions and the proximity of groundwater, as evidenced by the salt marshes in the arid regions of the taiga, tundra and arctic zones.

Rice. 9.1. Fanning cones (proluvial plumes) in the deserts of Turkmenistan.

Subtropical zone. In this climatic zone, the following main groups of soils are distinguished: soils of moist forests, dry forests and shrubs, dry subtropical steppes and low-grass semi-savannas, as well as subtropical deserts.

1. Red soils and yellow soils landscapes of humid subtropical forests

These soils are widespread in subtropical East Asia (China and Japan) and in the southeastern United States (Florida and neighboring southern states). They are also found in the Caucasus - on the coast of the Black (Adjara) and Caspian (Lankaran) seas.

The characteristic type of soils in humid subtropics is red earth, named for their color, due to the composition of the parent rocks. The main parent rock on which red soils develop is a layer of redeposited weathering products of a specific brick-red or orange color. This color is due to the presence of strongly bound Fe (III) hydroxides on the surface of clay particles. The red earths inherited from the parent rocks not only color, but also many other properties.

Soil profile structure:

A 0 - poorly decomposed forest litter, consisting of leaf litter and thin branches. The thickness is 1–2 cm.

А 1 - a gray-brown humus horizon with a reddish tint, with a large number of roots, a lumpy structure and a thickness of 10–15 cm. The humus content in this horizon is up to 8%. Down the profile, the humus content decreases rapidly.

B - transitional horizon of brownish-red color, the red tint intensifies downward. Dense, lumpy structure, along the paths of dead roots, streaks of clay are visible. The thickness is 50-60 cm.

C - parent rock of red color with whitish spots, clay pellets are found, there are small ferromanganese nodules. Films and streaks of clay are noticeable in the upper part.

Krasnozems are characterized by an acidic reaction of the entire soil profile (pH = 4.7–4.9).

Yellow soils are formed on clay shales and clays with poor water permeability, as a result of which gleying processes develop in the surface part of the profile of these soils, which cause the formation of oxide-ferruginous nodules in the soils.

The soils of humid subtropical forests are poor in nitrogen and some ash elements. To increase fertility, organic and mineral fertilizers are needed, primarily phosphates. The development of soils in humid subtropics is complicated by strong erosion that develops after deforestation, therefore, the agricultural use of these soils requires anti-erosion measures.

2. Brown soils landscapes of dry subtropical forests and shrubs

The soils, called brown soils, formed under dry forests and shrubs, are widespread in southern Europe and northwest Africa (Mediterranean region), southern Africa, the Middle East, and several regions of Central Asia. Such soils are found in warm and relatively dry regions of the Caucasus, on the southern coast of Crimea, in the Tien Shan mountains. In North America, soils of this type are common in Mexico; under dry eucalyptus forests, they are known in Australia.

Brown soils formed under dry forests of various species composition. In the Mediterranean, for example, these are forests of evergreen oak, laurel, seaside pine, treelike juniper, as well as dry shrubs such as shibliak and maquis, hawthorn, hold-tree, fluffy oak, etc.

Profile structure of brown soils:

А 1 - humus horizon of brown or dark brown color, lumpy structure, si with a thickness of 20–30 cm. The humus content in this horizon is 2.0–2.4%. Down the profile, its content gradually decreases.

B - a compacted transitional horizon of bright brown color, sometimes with a reddish tint. This horizon often contains new carbonate formations, in relatively humid regions they are located at a depth of 1–1.5 m, in arid regions they may already be in the humus horizon.

C - parent rock.

D - with a small thickness of the parent rock below the transitional horizon, the underlying rock is located (limestone, shale, etc.).

The reaction of soils in the upper part of the profile is close to neutral (pH = 6.3), in the lower part it becomes slightly alkaline.

The soils of subtropical dry forests and shrubs are highly fertile and have been used for a long time for agriculture, including viticulture, olive and fruit trees. Deforestation to expand cultivated land, combined with mountainous terrain, has contributed to soil erosion. So in many Mediterranean countries, the soil cover was destroyed and many areas that once served as granaries of the Roman Empire are now covered with desert steppes (Syria, Algeria, etc.).

3. Dry gray soils subtropics

In the arid landscapes of the semi-deserts of the subtropical belt, gray soils are formed , they are widely represented in the foothills of the ranges of Central Asia. They are distributed in the north of Africa, in the continental part of the south of North and South America.

Forests are predominantly soil-forming rocks.

Profile structure of sierozem:

A - light gray humus horizon, noticeably sodden, unclear lumpy structure, 15–20 cm thick. The amount of humus in this horizon is about 1.5–3%; down the profile, the humus content decreases gradually.

А / В - intermediate horizon between humus and transitional horizons. Loose, than humus, thickness - 10-15 cm.

B - brownish-fawn transitional horizon, poorly compacted, contains carbonate new formations. At a depth of 60–90 cm, gypsum neoplasms begin. It passes to the parent rock gradually. The thickness is about 80 cm.

C - parent rock

The entire profile of gray soils bears traces of intensive activity of earthmoving - worms, insects, lizards.

The serozems of the semi-deserts of the subtropical belt are bordered by the gray-brown soils of the deserts of the temperate zone and are connected with them by gradual transitions. However, typical serozem soils differ from gray-brown soils by the absence of a surface porous crust, a lower carbonate content in the upper part of the profile, a significantly higher humus content, and a lower location of gypsum neoplasms.

In gray soils there is a sufficient amount of chemical elements necessary for plant nutrition, with the exception of nitrogen. The main difficulty in their agricultural use is associated with the lack of water; therefore, irrigation is important for the development of these soils. Thus, rice and cotton are cultivated on irrigated gray soils in Central Asia. Farming without special irrigation is possible mainly in elevated areas of the foothills.

Tropical zone. The tropics here means the territory between the northern and southern tropics, i.e. parallels with latitudes. This territory includes tropical, subequatorial and equatorial climatic zones.

Tropical soils occupy more than 1/4 of the world's land surface. The conditions of soil formation in the tropics and countries of high latitudes are sharply different. The most notable distinctive features of tropical landscapes are climate, flora and fauna, but these differences are not limited to.

Red-colored deposits have a sandy-loamy composition, their thickness varies from several decimeters to 10 m and more. These deposits were formed in rather humid conditions, favorable for the high geochemical activity of iron. These deposits contain iron oxide, which gives the deposits a red color.

Along with red-colored sediments, lacustrine loams with a gray color, light yellow sandy loam alluvial deposits, brown volcanic ash, etc. can act as parent rocks; therefore, soils formed under the same bioclimatic conditions are not always the same color.

1. Soils of landscapes rainforests (constantly humid) tropical forests

Constantly humid rainforests are distributed over a large area in South America, Africa, Madagascar, Southeast Asia, Indonesia, the Philippines, New Guinea and Australia. Soils are formed under these forests, for which different names have been proposed at different times - red-yellow lateritic, ferralite and etc.

The humus horizon of the rain forest soil is gray, very thin (5–7 cm) and contains only a few percent of humus. It is replaced by a transitional horizon A / B (10–20 cm), during which the humus hue completely disappears.

The peculiarity of these biocenoses is that almost the entire mass of chemical elements necessary for plant nutrition is contained in the plants themselves and only because of this is not washed out by abundant atmospheric precipitation. When the rainforest is cleared, atmospheric precipitation very quickly erodes the upper thin fertile soil layer and barren lands remain under the cleared forest.

2. Soils of tropical landscapes seasonal atmospheric humidification

Light tropical forests are characterized by a free arrangement of trees, an abundance of light and, as a result, a lush cover of grasses. High-grass savannas are various combinations of grassy vegetation with islands of forest or individual specimens of trees. The soils forming under these landscapes are called red or ferralitic soils of seasonally humid tropical forests and tall grass savannas

The profile structure of these soils:

Above there is a humus horizon (A), in the upper part it is more or less soddy, 10–15 cm thick, dark gray in color. Below is the transitional horizon (B), during which the gray shade gradually disappears and the red color of the parent rock intensifies. The thickness of this horizon is 30–50 cm. The total humus content in the soil is from 1 to 4%, sometimes more. The reaction of soils is slightly acidic, often almost neutral.

These soils are widely used in tropical agriculture. The main problem with their use is the easy destruction of soils under the influence of erosion.

When the dry period lasts from 7 to 10 months a year and the annual precipitation amount is 400–600 mm, xerophytic biocenoses develop, which are a combination of dry tree and shrub thickets and low grasses. The soils forming under these landscapes are called reddish-brown soils of dry savannas.

The structure of these soils:

Under the humus horizon A, about 10 cm thick, of a slightly gray shade, there is a transitional horizon B, 25–35 cm thick. In the lower part of this horizon, sometimes there are carbonate concretions. This is followed by the parent rock. The humus content in these soils is usually low. The reaction of the soils is slightly alkaline (pH = 7.0–7.5).

These soils are widespread in the central and western regions of Australia, in some areas of tropical Africa. They are of little use for agriculture and are mainly used for pastures.

With an annual precipitation of less than 300 mm, soils are formed arid tropical (semi-desert and desert) landscapes, having common features with gray-brown soils and gray soils. They have a thin and poorly differentiated carbonate profile. Since the parent rocks in many regions are red products of [Neogene] weathering, these soils are reddish in color.

Tropical Islands Zone. A special group is formed by the soils of the oceanic islands of the tropical belt of the World Ocean, among them the most peculiar are the soils of coral islands - atolls.

White coral sands and reef limestones serve as the parent rock on these islands. The vegetation is represented by thickets of shrubs and forests of coconut trees with an intermittent cover of low grasses. Here the most common atoll humus-calcareous sandy soils with a thin humus horizon (5–10 cm), characterized by a humus content of 1–2% and a pH of about 7.5.

Avifauna is often an important factor in soil formation on islands. Colonies of birds deposit huge amounts of droppings, which enrich the soil with organic matter and contribute to the emergence of special woody vegetation, thickets of tall grasses and ferns. A powerful peat-humus horizon with an acid reaction is formed in the soil profile. Such soils are called atoll melano-humus-carbonate.

Rice. 9.2. Coral barrier reef in French Polynesia

Rice. 9.3 Atoll in the area of ​​about. Moorea in the Pacific

Humus-carbonate soils are an important natural resource of numerous island states in the Pacific and Indian Oceans, being the main plantation for the coconut palm.

Mountainous area. Mountain soils occupy more than 20% of the entire land surface. In mountainous countries, the same combination of soil formation factors is repeated in the main features as on the plains, therefore many soils of the type of automorphic soils of plain territories: podzolic, chernozems, etc. are widespread in the mountains. However, the formation of soils in mountainous and soils formed in flat and mountainous areas are clearly different. Allocate mountain-podzolic, mountain chernozems, etc. In addition, in mountainous areas such conditions are formed in which specific mountain soils are formed that have no analogues on the plains (for example, mountain-meadow soils).

Rice. 9.4. Akhyr mountains near the city of Kahramanmaras in the south of central Turkey.

One of the distinctive features of the structure of mountain soils is the low thickness of the genetic horizons and the entire soil profile. The thickness of the profile of a mountain soil can be 10 or more times less than the thickness of the profile of a similar flat soil, while maintaining the structure of the profile of a flat soil and its features.

Zone of arctic deserts. In this zone lie Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, New Siberian Islands. The zone is characterized by a huge amount of ice and snow in all seasons of the year. They are the main element of the landscape.

All year round, the arctic air prevails here, the radiation balance for the year is less than 400 mJ / m 2, the average July temperatures are 4-2 ° С. The relative humidity is very high - 85%. Precipitation falls 400-200 mm, and almost all of them fall in solid form, which contributes to the emergence of ice sheets and glaciers. However, in some places, the supply of moisture in the air is small, and therefore, with an increase in temperature and strong winds, a large lack of moisture is formed and strong evaporation of snow occurs.

The soil-forming process in the Arctic takes place in a thin active layer and is at the initial stage of development. In the valleys of rivers and streams and on sea terraces, two types of soils are formed - typical polar desert soils on polygonal drained plains and polar desert solonchaks in saline coastal areas. They are characterized by a low humus content (up to 1.5%), weakly expressed genetic horizons and a very low thickness. In the arctic deserts, there are almost no swamps, few lakes, salt spots form on the soil surface in dry weather with strong winds.

The vegetation cover is extremely sparse and patchy; it is characterized by a poor species composition and extremely low productivity. Low-organized plants dominate: lichens, mosses, algae. The annual growth of mosses and lichens does not exceed 1–2 mm. Plants are extremely selective in their distribution. More or less closed groupings of plants exist only in places sheltered from cold winds, on fine earth, where the thickness of the active layer is greater.

The main background of the Arctic deserts is formed by crustose lichens. Hypnum mosses are common, sphagnum mosses appear only in the south of the zone in very limited quantities. Higher plants are characterized by saxifrage, polar poppy, crumbs, stellate, Arctic pike, bluegrass and some others. Cereals thrive, forming hemispherical cushions up to 10 cm in diameter on a fertilized substrate near nesting gulls and burrow lemmings. At the spots of snow, an ice buttercup and a polar willow grow, reaching only 3-5 cm in height. Fauna, like flora, is poor in species; there are lemming, arctic fox, reindeer, polar bear, and ptarmigan and snowy owl are ubiquitous among birds. On the rocky shores there are numerous bird colonies - massive nesting sites of seabirds (guillemots, luriks, ivory gulls, fulmars, eiders, etc.). The southern shores of Franz Josef Land, the western shores of Novaya Zemlya are a continuous bird colony.

Soil is the thin top layer of the earth's crust that gives life to plants. This is an independent natural body, which is a cross between living and dead matter. The lithosphere, atmosphere, hydrosphere and biosphere interact in the soil, and the density of the living matter of the planet is maximum.

The most valuable property of the soil is fertility, i.e. the ability to provide plants with the necessary nutrients and moisture.

The soil consists of mineral particles, organic matter mainly of plant origin, soil water, soil air and living organisms inhabiting it. In different regions of the Earth, soil thickness ranges from a few centimeters to 2-3 meters.

Soil formation depends on a combination of soil formation factors that differ over vast areas of the Earth. For example, where it is low, there is little rainfall and vegetation is scarce, the soil layer is thin and contains little humus. But in areas with a sufficient amount of heat and precipitation, with rich herbaceous vegetation, powerful fertile soils are formed.

The Sun heats the spherical surface of the Earth unevenly: the areas above which it stands high receive the most heat. The farther from the equator, the greater the angle the rays reach the earth's surface and, therefore, less thermal energy per unit area. Above the poles, the Sun's rays only glide over the Earth. The climate depends on this: hot at the equator, harsh and cold at the poles. The main features of the distribution of flora and fauna are also related to this. According to the features of heat distribution, seven heat zones are distinguished. In each hemisphere there are zones of eternal frost (around the poles), cold, moderate. The hot belt at the equator is one for both hemispheres. Heat zones are the basis for dividing the earth's surface into geographic zones: areas that are similar in the prevailing types of landscapes - natural-territorial complexes that have a common soil, vegetation and fauna.

But the land surface of the Earth in different places receives not only different amounts of solar energy, but also has many additional dissimilar conditions - for example, remoteness from the oceans, uneven relief (mountain systems or plains) and, finally, unequal height above sea level. Each of these conditions strongly affects the natural features of the Earth.

Plants and animals, fungi and microorganisms belong to living nature, and rocks, air, surface and ground waters - to inanimate nature. All of them are integral parts of natural complexes, in a wide variety presented on Earth. A natural complex located in a limited area is called a landscape. A separate landscape can be called the top of a hill overgrown with spruce forest or a flood meadow in the river valley. Climate, relief, water, soil, plants and animals are the main components of the landscape, they interact with each other in a complex way, forming a single natural system. The upper boundary of the landscape is that part of the troposphere where dust of terrestrial origin spreads, and the lower boundary is the horizon of groundwater.

Landscapes are the building blocks of more complex natural systems, such as natural areas. Each continent has its own characteristic set, and all together the continents and oceans make up the largest and most complex natural system - a geographic shell. The word "system" is translated from Greek as "whole, consisting of parts."

At present, almost all landscapes of the planet are disturbed to one degree or another. Man has created some landscapes anew, for example, quarries for the extraction of minerals, reservoirs, cities. Nowadays, the influence of man on nature is enormous. However, it is necessary to understand that by thoughtlessly interfering with its laws, we cause colossal harm to nature, and therefore to ourselves. After all, the life and health of people are directly related to the state of the environment, therefore, the preservation of nature is the main condition for the very existence of mankind. Only a careful and reasonable attitude to natural resources will allow avoiding a global ecological catastrophe, preserving our planet for future generations.

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