What is formed in the soil. Concept of soil

Soil is a special natural body formed on the surface of the Earth as a result of the interaction of living (organic) and dead (inorganic) nature. The most important property of soil, which distinguishes it from rocks, is fertility. It is caused by the presence of organic matter, humus, or humus, in soils. Due to their fertility, soils are the greatest natural wealth, which must be used very wisely. Soils form very slowly: over 100 years, soil thickness increases by 0.5 - 2 cm.

Soil formation factors

Outstanding Russian scientist - founder of soil science (pedology) V.V. wrote that soil is the “mirror” of nature. , climate, water, microorganisms, plants and animals are involved in the formation of soils. Among these factors, human activity occupies a special place.
Soil structure. The formation of soils involves the formation of humus and the movement of organic matter, and the formation of humus and the movement of organic and mineral compounds within the soil profile.

The upper horizon is humus. It is densely permeated with roots. Here the accumulation of organic matter and the formation of humus occurs. The humus horizon is the darkest. Its color depends on the accumulated humus. The amount of humus decreases from top to bottom, so the horizon is lighter in the lower part. When precipitation falls and snow melts, moisture seeps through the humus horizon, which dissolves and removes some of the organic and mineral compounds from it. In soils formed under conditions of large soil conditions, a leaching horizon forms under the humus horizon.

This is a very clarified horizon, from which a significant part of organic and mineral compounds has been removed.

Sometimes everything that can dissolve is taken out, and only silica remains. This is a podzolic horizon.

Below lies the washout horizon. It receives what the upper part of the soil loses. Beneath it is a slightly altered parent rock, on which the process of soil formation initially began. There is a continuous exchange of matter between the soils through the circulation of the soil solution.

According to the structure of the soil profile, i.e. Based on the degree of expression of individual horizons, their thickness and chemical composition, they determine whether the soil belongs to a certain type.

According to the mechanical composition - the ratio of different sized mineral particles (sand, clay) soils are divided into clayey, loamy and sandy.

The maintenance of water and air regimes favorable for plants is facilitated by soil structure - the ability of soil particles to combine into relatively stable lumps. The shape and size of lumps are not the same in different types of soil. The best is a granular, or finely lumpy, structure with lumps with a diameter of 1 - 10 mm. If there is little humus and clay particles, then such soils are usually structureless (sandy and often sandy loam).

Soil diversity and placement

The type, mechanical composition, structure of the soil, its fertility, etc. depend on the combination of soil formation factors in specific conditions. The distribution of soils on Earth depends primarily on. There is a change in soils, and in the mountains - from the foot to the peaks.

Under the same climate, soil diversity is determined by topography and rocks. Each territory is characterized by its own combinations of soils with certain properties. The main types of soils common in Russia are: tundra-gley, podzolic, gray forest, chestnut.

The content of the article

THE SOIL- the most superficial layer of land on the globe, resulting from changes in rocks under the influence of living and dead organisms (vegetation, animals, microorganisms), solar heat and precipitation. Soil is a completely special natural formation, possessing only its own inherent structure, composition and properties. The most important property of 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 nourish plants; it is precisely by its fertility that the soil, as a natural body, differs from all other natural bodies (for example, barren stone), which are not capable of meeting the needs of plants for 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 Earth’s biosphere as a whole; through the Earth’s soil cover there are numerous ecological connections of all organisms living on and in the earth (including humans) with the lithosphere, hydrosphere and atmosphere.

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 to solve a number of problems in health care, exploration and mining of mineral resources, organization of green areas in urban areas, 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, mathematical, chemical, biological, geological and geographical sciences, and is 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 verifies and uses the identified patterns and, in turn, stimulates new searches in the field of theoretical knowledge. To date, large applied areas of soil science have been formed for agriculture and forestry, irrigation, construction, transport, mineral exploration, healthcare and environmental protection.

Since the systematic practice of agriculture, mankind has first studied the soil empirically and then using scientific methods. The most ancient attempts to evaluate various soils are known in China (3 thousand BC) and Ancient Egypt. In Ancient Greece, the idea of ​​soil developed in the process of the development of ancient natural philosophy. During the period of the Roman Empire, a large number of empirical observations on the properties of the soil were accumulated and some agronomic techniques for its 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 disintegration of the feudal system), interest in the study of soils in connection with the problem of plant nutrition arose again. 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 absorb minerals from the soil, and only carbon in the form of carbon dioxide from humus. Yu. Liebig believed that each harvest depletes the supply of mineral substances in the soil, therefore, in order to eliminate this deficiency of elements, it is necessary to apply factory-prepared mineral fertilizers to the soil. Liebig's merit was the introduction of mineral fertilizers into agricultural practice.

The importance of nitrogen for soil was studied by the French scientist J.Yu. Boussingault.

By the middle of the 19th century. Extensive material on the study of soils has accumulated, but this data was scattered, not systematized and not generalized. There was no uniform definition of the term soil for all researchers.

The founder of soil science as an independent natural-historical science was the outstanding Russian scientist Vasily Vasilyevich Dokuchaev (1846–1903). Dokuchaev was the first to formulate a scientific definition of soil, calling 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 soil formation factors 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 formation of soil occurs as a result of the combined action of all soil-forming factors. He established a view of the soil as an independent special natural body, equivalent to the concepts of plant, animal, mineral, etc., which arises, develops, and 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 individual 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 natural replacement of some soils by others as they rise from the foot to the top of high mountains. He also owned the first scientific classification of soils, which was based on the entire set of the most important soil characteristics and properties. Dokuchaev’s classification was recognized by world science and the names he proposed “chernozem”, “podzol”, “solonchak”, “solonetz” became 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 he compiled the first soil map of the northern hemisphere (this map was called “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.)

Important research to understand the processes of soil formation and study the soils of different territories was carried out by scientists from other countries. This is E.V. Gilgard (USA); E.Ramann, E.Blank, V.I.Kubiena (Germany); A. de Zsigmond (Hungary); J. Milne (Great Britain), J. Aubert, R. Menien, J. Durand, N. Leneff, G. Erard, F. Duchaufour (France); J. Prescott, S. Stephens (Australia) and many others.

To develop theoretical ideas and successfully study the soil cover of our planet, business connections between different national schools are necessary. In 1924 the International Society of Soil Sciences was organized. For a long time, from 1961 to 1981, a large and complex work was carried out to compile the Soil Map of the World, in the compilation of which Russian scientists played a large role.

Methods for studying soils.

One of them is comparative geographical, based on a simultaneous study of the soils themselves (their morphological characteristics, physical and chemical properties) and soil formation factors in different geographical conditions, followed by their comparison. Nowadays, soil research uses various chemical analyses, analyzes of physical properties, mineralogical, thermochemical, microbiological and many other analyses. As a result, a certain connection is established in changes in certain soil properties with changes in soil-forming factors. Knowing the patterns of distribution of soil-forming factors, it is possible to create a soil map for a wide area. It was in this way that Dokuchaev made the first world soil map in 1899, known as “Schemes of soil zones of the Northern Hemisphere.”

Another method is the method of stationary research consists in the systematic observation of any 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 to immediately collapse. The sum of the processes of transformation of rocks on the Earth's surface is called weathering or hypergenesis. The totality of weathering products is called weathering crust. The process of transformation of parent rocks into weathering crust is extremely complex and includes numerous processes and phenomena. Depending on the nature and causes of destruction of rocks, physical, chemical and biological weathering is distinguished, which usually comes down to the physical and chemical effects of organisms on rocks.

Weathering processes (hypergenesis) extend to a certain depth, forming a hypergenesis zone . The lower boundary of this zone is conventionally drawn along the roof of the upper horizon of groundwater (formation) water. The lower (and most) part of the hypergenesis zone is occupied by rocks that have been modified to varying degrees by weathering processes. Here, the newest and ancient weathering crusts, formed in more ancient geological periods, are distinguished. The surface layer of the hypergenesis zone is the substrate on which soil formation occurs. How does the process of soil formation occur?

During the process of weathering (hypergenesis), the original appearance of rocks changed, as did their elemental and mineral composition. Initially massive (ie dense and hard) rocks gradually turned into a fragmented state. Examples of rocks crushed as a result of weathering include gruss, sand, and clay. Becoming fragmented, rocks acquired a number of new properties and features: they became more permeable to water and air, the total surface of their particles increased, increasing chemical weathering, new compounds were formed, including easily soluble in water compounds and, finally, rocks 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. Easily soluble compounds formed as a result of weathering can only be washed out of rocks under the influence of precipitation; and such a biologically important element as nitrogen, consumed by plants in large quantities, is completely absent from igneous rocks.

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

Therefore, the beginning of the soil formation process should be considered the moment when vegetation and microorganisms settled on the weathering products of rocks. From that moment on, the crushed rock became soil, i.e. a qualitatively new body, possessing a number of qualities and properties, the most significant of which is fertility. In this regard, all existing soils on the globe represent 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 originated, the soil-forming process never stopped.

Soil formation factors.

The development of the soil-forming process is most directly influenced by the natural conditions in which it occurs; its characteristics 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 soil-forming factors, 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), the action of water (soil and groundwater) and human activity are now added. The biological factor is always of leading importance, while the remaining factors represent only the background against which soil development occurs in nature, but they have a great influence on the nature and direction of the soil-forming process.

Soil-forming rocks.

All existing soils on Earth originate from rocks, so it is obvious that they are directly involved in the process of soil formation. The chemical composition of the rock is of greatest importance, since the mineral part of any soil contains mainly 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 most directly influence not only the intensity, but also the nature of the ongoing soil-forming processes.

Climate.

Climate plays a huge role in soil formation processes; 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 characteristics of their daily and seasonal distribution, determine completely specific soil formation processes. Climate influences the nature of rock weathering and affects the thermal and water regimes of the soil. The movement of air masses (wind) affects gas exchange in the soil and captures small particles of soil in the form of dust. But climate affects the soil not only directly, but also indirectly, since the existence of this or that 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 large and diverse. By penetrating the upper layer of soil-forming rock with their roots, plants extract nutrients from its lower horizons and fix them in synthesized organic matter. After the mineralization of dead parts of plants, the ash elements contained in them are deposited in the upper horizon of the soil-forming rock, thereby creating favorable conditions for feeding the next generations of plants. Thus, 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 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.

As soil organic matter decomposes, acids are released, which, acting on the parent rock, enhance its weathering.

The plants themselves, in the process of their life activity, secrete various weak acids through their roots, under the influence of which sparingly soluble mineral compounds partially transform into a soluble form, and therefore into a form that is assimilated by plants.

In addition, vegetation cover significantly changes microclimatic conditions. For example, in a forest, compared to treeless areas, summer temperature is lowered, air and soil humidity is increased, wind force and water evaporation over 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 they contain are synthesized into compounds 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 specific soil type. For example, chernozem, which is formed under the influence of meadow-steppe vegetation, will never form under the vegetation formation of coniferous forests.

Animal world.

Animal organisms, of which there are many in the soil, are important for soil formation. The most important are invertebrate animals living in the upper soil horizons and in plant debris on the surface. In the process of their life activity, 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 also play an important role, such as moles, mice, gophers, marmots, etc. By repeatedly breaking up the soil, they contribute to the mixing of organic substances with minerals, as well as increasing the water and air permeability of the soil, which enhances and accelerates the processes of 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 soil cover. Its role is reduced mainly to the redistribution of heat and humidification. A significant change in the altitude of the area entails significant changes in temperature conditions (it becomes colder with altitude). This is related to the phenomenon of vertical zoning in the mountains. Relatively small changes in altitude affect the redistribution of precipitation: low areas, basins and depressions are always more moistened than slopes and elevations. The exposure of the slope determines the amount of solar energy reaching the surface: southern slopes receive more light and heat than northern ones. Thus, relief features change the nature of climate influence on the process of soil formation. Obviously, in different microclimatic conditions, soil formation processes will proceed differently. Of great importance in the formation of soil cover is the systematic washout and redistribution of fine earth particles by precipitation and melt water along relief elements. Relief is of great importance in conditions of heavy precipitation: areas deprived of natural drainage of excess moisture are very often subject to waterlogging.

Soil age.

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

There are absolute and relative ages of soils. The absolute age of soils is the period of time that has passed from the formation of the soil to the current 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 different parts of the land that were simultaneously freed from water or glacial cover, soils will not always go through the same stage of development at each given moment. The reason for this may be differences in the composition of soil-forming rocks, relief, vegetation and other local conditions. The difference in the stages of soil development on the same general territory, which has the same absolute age, is called the relative age of the soils.

The development time of a mature soil profile for different conditions ranges 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 geographical conditions of soil formation, soils that have different ages and development histories can differ significantly and belong to different classification groups.

Soil age is therefore one of the most important factors to consider when studying a particular soil.

Soil and groundwater.

Water is the medium in which numerous chemical and biological processes occur in the soil. Where groundwater is shallow, it has a strong impact on soil formation. Under their influence, the water and air regimes of soils change. Groundwater enriches the soil with the chemical compounds it contains, sometimes causing salinization. Waterlogged soils contain insufficient oxygen, which suppresses the activity of certain groups of microorganisms.

Human economic activity influences some factors of soil formation, for example, vegetation (deforestation, replacing it with herbaceous phytocenoses, etc.), and directly on soils through mechanical cultivation, irrigation, application of mineral and organic fertilizers, etc. As a result, soil-forming soil processes and properties change. Due to the intensification of agriculture, human influence on soil processes is continuously increasing.

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

All factors do not influence in isolation, but in close relationship 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 influence on all soil formation factors, causing certain changes in each of them. Thus, due to the inextricable connection between vegetation and soils, any change in vegetation is inevitably accompanied by a change in soils, and, conversely, a change in soils, especially 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 varies not only in different soils, but also in different horizons of the same soil. There is a natural 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 minerals of lithogenic origin. These are fragments and particles of primary minerals of various sizes (quartz, feldspars, hornblende, mica, etc.), formed during the 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 composition. 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, significantly less trace elements: Cu, Mo, I, B, F, Pb, etc. The vast majority of elements are in the oxidized form. Many soils, mainly in the soils of insufficiently moistened areas, contain a significant amount of calcium carbonate CaCO 3 (especially if the soil was formed on carbonate rock), in the soils of arid areas - CaSO 4 and other more easily soluble salts (chlorites); soils in humid tropical areas are enriched in Fe and Al. However, the implementation of these general patterns depends on the composition of soil-forming rocks, the age of the soils, relief features, climate, etc.

The solid part of the soil also contains organic matter. There are two groups of organic substances in the soil: those that entered the soil in the form of plant and animal residues and new, specific humic substances. substances resulting from the transformation of these residues. There are gradual transitions between these groups of soil organic matter; according to 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 waste products of plants, animals and microorganisms. These are proteins, carbohydrates, organic acids, fats, lignin, resins, etc. These compounds in total constitute 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, resulting from 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 . Carbon, oxygen, hydrogen, nitrogen and phosphorus play an important role in the elemental composition of humic substances. Humus contains the basic 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 products of the decomposition of organic compounds of the first group.

When organic matter decomposes in the soil, the nitrogen it contains 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 organomineral structural units (lumps). The structure of the soil that arises in this way largely determines its physical properties, as well as water, air and thermal regimes.

The liquid part of the soil or, as it is also called, soil solution – this is the water contained in the soil with gases, mineral and organic substances dissolved in it, which entered it when passing through the atmosphere and seeping through the soil layer. The composition of soil moisture is determined by soil formation processes, vegetation, general climate characteristics, as well as the time of year, weather, human activities (fertilizer application, etc.).

Soil solution plays a huge role in soil formation and plant nutrition. Basic chemical and biological processes in the soil can only occur in the presence of free water. Soil water is the medium in which the migration of chemical elements occurs during the process of soil formation, supplying plants with water and dissolved nutrients.

In non-saline soils, the concentration of substances in the soil solution is small (usually does not exceed 0.1%), and in saline soils (salt marshes and solonetzes) it is sharply increased (up to whole and even tens of percent). A 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 different types of soil is not the same: acidic reaction (pH 7) - soda solonetzes, neutral or slightly alkaline (pH = 7) - ordinary chernozems, meadow and brown soils. Too acidic and too alkaline soil solutions have a negative effect on plant growth and development.

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) ranges from 25 to 60% of the soil volume ( cm. Morphological characteristics of soils). The relationship 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 atmospheric air and is determined by the nature of the many chemical, biochemical, and biological processes occurring in the soil. The composition of soil air is not constant; depending on external conditions and the time of year, it can vary significantly. For example, the amount of carbon dioxide (CO 2) in soil air varies significantly in the annual and daily cycles due to different rates of gas release by microorganisms and plant roots.

There is constant gas exchange between soil and atmospheric air. The 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 between the soil and the atmosphere can be hampered 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 normal plant development is possible only under conditions of sufficient air access to the soil. If there is insufficient penetration of oxygen into the soil, plants are inhibited, their growth slows down, and sometimes they die completely.

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 therefore 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 the soil air may contain some gases that penetrate through rock strata from places where they accumulate; special gas geochemical methods for searching for mineral deposits are based on this.

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

The main sources of soil water are precipitation. Some 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 occurs as follows. Part of the water that reaches the soil surface flows off as surface runoff. The largest amount of moisture entering the soil is absorbed by plants, which then partially evaporate it. Some water is consumed by 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 intrasoil runoff, a temporary phenomenon that occurs during periods of seasonal soil moisture. At this time, gravitational water begins to move along the most permeable soil horizon, the aquifer for which is the less permeable horizon. Such seasonally existing waters are called high water. Finally, a significant part of the soil water can reach the surface of the groundwater, the outflow of which occurs through a waterproof bed-aquitard, and leave as part of the groundwater runoff.

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

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 entry with water into 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 accumulating, preserving, rationally using soil moisture, and, in necessary cases, irrigating or draining the 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, and on cultivated soils - on the characteristics of the cultivated plants and their cultivation techniques.

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

Pripromyvny type of water regime, the entire soil layer is annually soaked to groundwater, while the soil returns less moisture to the atmosphere than it receives (excess moisture seeps into groundwater). Under the conditions of this regime, the soil-ground layer is annually washed by gravitational water. The flushing 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 wetting of the soil layer. Atmospheric moisture penetrates into the soil to a depth of several decimeters to several meters (usually no more than 4 m), and between the soaked soil layer and the upper boundary of the capillary fringe of groundwater, a horizon with constant low humidity (close to wilting humidity) appears, called a dead desiccation horizon . This regime differs in that the amount of moisture returned to the atmosphere is approximately equal to its input 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 conditional 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.

Vypotnoy This type of water regime is observed in dry climates with a sharp predominance of evaporation over precipitation, in soils that are fed not only by precipitation, but also by the moisture of shallow groundwater. With the effusion type of water regime, groundwater reaches the soil surface and evaporates, which often leads to soil 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 precipitation exceeds the sum of evaporation and water absorption by plants. Due to excess moisture, perched water forms, resulting in waterlogging of the soil. This type of water regime is typical for depressions in the relief.

The permafrost (cryogenic) type of water regime is formed in the territory of continuous permafrost. Its peculiarity is the presence of a permanently frozen aquifer at shallow depths. As a result, despite the small amount of precipitation, in the warm season the soil is oversaturated with water.

The thermal regime of the soil is the sum of heat exchange phenomena in the system surface layer of air - soil - soil-forming 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 primarily by the ratio between absorbed solar radiation and thermal radiation of the soil. The features of this relationship determine the differences in the regime of different soils. The thermal regime of the soil is formed mainly under the influence of climatic conditions, but it is also influenced by the thermophysical properties of the soil and 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 rocks have a special impact on the thermal regime of the soil.

Thermal energy of the soil is involved in phase transitions of soil moisture, released during ice formation and condensation of soil moisture and consumed during ice melting and evaporation.

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

Daily fluctuations in soil temperature cover soil thickness from 20 cm to 1 m, annual fluctuations up to 10–20 m. Soil freezing depends on the climatic characteristics of a given area, the freezing temperature of the soil solution, the thickness of the snow cover and the time of its fall (since snow cover reduces soil cooling). The depth of soil freezing rarely exceeds 1–2 m.

Vegetation has a significant influence on the thermal regime of the soil. It delays 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 occurring in the soil. For example, the intensity of the biochemical activity of bacteria increases with increasing soil temperature to 40–50° C; Above this temperature, the vital activity of microorganisms is inhibited. At temperatures below 0° C, biological phenomena are sharply inhibited and stop. The thermal regime of the soil has a direct impact on the growth and development of plants. An important indicator of the supply of soil heat to plants is the sum of active soil temperatures (i.e. temperatures above 10 ° C, at these temperatures active plant growth occurs) at the depth of the arable layer (20 cm).

Morphological characteristics of soils.

Like any natural body, soil has a sum of external, so-called morphological characteristics, 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 characteristics of soil are: soil profile, soil color and color, soil structure, granulometric (mechanical) composition of soils, soil composition, 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 the science. Since science is constantly developing, classification is improving accordingly.

In the pre-Dokuchaev period, they did not study the soil (in the modern sense), but only its individual properties and aspects, and therefore they classified the soil according to its individual properties - chemical composition, granulometric composition, etc.

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

Dokuchaev adopted genetic soil types formed by a certain combination of soil-forming factors as the main classification unit. This genetic classification of soils is based on the structure of the soil profile, reflecting the process of soil development and their regimes. The modern classification of soils used in our country is a developed and expanded classification of 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 soil formation process, which develops under conditions of the same thermal and water regimes, on parent rocks of similar composition and under the same type of vegetation, are combined into one genetic type. Depending on soil moisture, they are combined into rows. There are a number of automorphic soils (i.e. soils that receive moisture only from precipitation and on which groundwater does not have a significant impact), hydromorphic soils (i.e. soils that are under significant influence of groundwater) and transitional automorphic soils. -hydromorphic soils.

Genetic types of soils are divided 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 accepted by all national schools and contributed to the clarification of the main patterns of soil geography.

Currently, a unified international classification of soils 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 developed in 1960 in the USA. The American classification is based not on an assessment of the conditions of formation and the associated genetic characteristics of various types of soils, but on taking into account easily detectable morphological characteristics of soils, primarily on the study of certain horizons of the soil profile. These horizons have been called diagnostic .

The diagnostic approach to soil taxonomy turned out to be very convenient for drawing up detailed large-scale maps of small areas, but such maps could practically not be compared with survey small-scale maps constructed on the basis of the principle of geographic-genetic classification.

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

Experts from the Food and Agriculture Organization of the United Nations (FAO), together with the United Nations Educational, Scientific and Cultural Organization (UNESCO), have begun creating 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 discussion and agreement between various national scientific schools. As a result, a map legend was developed, which was based on a diagnostic approach to determining classification units of all levels, although it also took into account individual 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, and certain concepts and wording in the map legend have been clarified.

Basic patterns of soil geography.

Studying the patterns of spatial distribution of different types of soils is one of the fundamental problems of the Earth sciences.

Identification of the patterns 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 main patterns were identified:

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

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

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

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

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

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

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

At first it was believed that the change in vertical soil zones is completely analogous to the horizontal zonation of soils from the equator to the poles, but later it was discovered that among mountain soils, along with types common both in the plains and in the mountains, there are soils that are formed only in mountain conditions landscapes. It was also found that a strict order of arrangement of vertical soil zones (belts) is very rarely observed. Individual 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 faciality. I.P. Gerasimov and other scientists have revealed that the manifestation of horizontal zoning is adjusted by the conditions of specific regions. Depending on the influence of ocean basins, continental spaces, and large mountain barriers on the path of air mass movement, local (facial) climate features are formed. This is manifested in the formation of features of local soils up to the appearance of special types, as well as in the complication of horizontal soil zonation. Due to the phenomenon of facies, even within the distribution of one soil type, soils can have significant differences.

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

Mosaic soil cover. In the process of detailed soil survey and soil-cartographic work, it was discovered 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 microrelief, variability in 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 varying degrees of genetically related soil habitats that form a specific soil pattern and structure, all of whose components 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., Mysl, 1979
Glazovskaya M.A., Gennadiev A.N. , M., Moscow State University, 1995
Maksakovsky V.P. Geographical picture of the world. Part I. General characteristics of the world. Yaroslavl, Upper Volga Book Publishing House, 1995
Workshop on general soil science. Moscow State University Publishing House, Moscow, 1995
Dobrovolsky V.V. Geography of soils with basics of soil science. M., Vlados, 2001
Zavarzin G.A. Lectures on natural history microbiology. M., Nauka, 2003
Eastern European forests. History in the Holocene and modern times. Book 1. Moscow, Science, 2004

Soils

The Russian Federation is characterized by a wide variety of bioclimatic conditions, which determine the diversity of soils on its territory. In addition to differences in the specifics of climate and modern ecosystems, the diversity of Russian soils is determined by the complexity of the geological structure and history of the upper cover of sediments on the earth's surface. As a rule, each type of natural biogeocenosis corresponds to a certain type or group of soil types. Together with climatic parameters, soils determine the nature of land use in agriculture. The geographical distribution of soils is regulated by the laws of soil geography, primarily latitudinal zonality and vertical zonation. Below is a description of the soils in the main natural zones of Russia.

Soils of the Arctic zone. The Arctic zone occupies a relatively small territory in Russia: it is distributed on the islands of the Arctic Ocean, such as Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, the northern part of the New Siberian Islands, as well as on the northern tip of the Taimyr Peninsula (Cape Chelyuskin). In the Arctic zone, soils occupy only ice-free areas where lichens and mosses grow, and in some places clumps of cereals. They thaw for 2–3 months a year to a depth of 20–30 cm. The granulometric composition of these soils is dominated by crushed stone and coarse sand fractions. The content of organic carbon in soils does not exceed 1.0–1.5% in the surface horizon, the reaction of the environment is close to neutral. Soils that form on the ocean coasts are characterized by the accumulation of salts and, in some places, salt efflorescence on the surface.

Soils of tundra and forest-tundra. The tundra zone stretches along the coast of the Arctic Ocean throughout the Russian North. It is characterized by milder climatic conditions than the Arctic zone and relatively continuous soil and vegetation cover, which is absent only on rock outcrops (the so-called rock formations) and on glaciers.

The tundra is divided into three subzones: arctic tundra, typical (lichen-moss) tundra and southern (shrub) tundra.

The Arctic tundra occupies a narrow strip along the ocean coast immediately south of the Arctic zone. Typical landscapes are patchy fissure-polygonal tundras, where patches devoid of soil and vegetation cover can occupy up to 40–80% of the total area. The main areas are occupied by the so-called. arctic-tundra soils. They form under shrub-grass-lichen-moss vegetation on loamy and clayey deposits of different origins and have a thin (3–6 cm) humus-accumulative horizon, under which lies a brown-colored middle horizon with bluish spots. This coloration diagnoses gleying - the process of reduction of iron and manganese under conditions of oxygen deficiency due to prolonged saturation of the soil with moisture. For many soils in this zone, cryoturbation is typical in their profile - signs of soil mixing as a result of its freezing and thawing. The soils are characterized by a relatively high content of organic carbon in the surface horizon (2.0–3.5%) and its deep penetration into the soil thickness, the reaction of the environment is neutral or close to neutral, and a high content of exchangeable bases, among which calcium predominates.

Typical tundra occupies vast areas in the north of the country, especially in the Asian part, and is characterized by more diverse and developed soils than the Arctic tundra. A significant part of the soil cover consists of tundra gley soils (see Gleyzems), which differ from arcto-tundra soils in a deeper profile, thawing up to 40–100 cm, and a more pronounced manifestation of gleying, which indicates long-term waterlogging. The tundra soils of the European part of Russia are characterized by surface gleying, and the soils of Eastern Siberia are characterized by supra-permafrost gleying. Unlike the soils of the Arctic tundra, tundra gley soils of typical tundra are characterized by an acidic reaction in the upper horizon, which changes to slightly acidic with depth. In addition to tundra gley soils, large areas in this zone are occupied by tundra swamp soils and podburs. Tundra swamp soils form on low, poorly drained relief elements. They are characterized by a constant stagnant water regime and slow decomposition of plant residues, which leads to the formation of peat on the soil surface; The thickness of peat deposits in the tundra is, as a rule, insignificant due to the low biological productivity of tundra ecosystems. On gravelly and sandy rocks with good water permeability, podburs are formed - acidic, without signs of gleying of the soil with a rusty-brown horizon under moss and shrub vegetation. A general feature of the tundra soil cover is its diversity and complexity, that is, the frequent alternation of small patches of different soils and bare areas devoid of vegetation, which is associated with harsh climatic conditions. The fertility of tundra soils is low, but the mosses and lichens growing on them serve as food for reindeer.

The southern shrub tundra, which turns into forest-tundra to the south, is characterized by a wide distribution of shrub thickets in river valleys. In the European part of Russia, these thickets consist of polar willow and bushy alder, and in the Far East they are represented mainly by dwarf cedar. The soils of the southern tundra are generally similar to the soils of the typical tundra, but the thickness of the active layer and, accordingly, the thickness of the soil profile here is greater.

The forest-tundra, which receives more heat than more northern zones, is characterized by the introduction of sparse and suppressed tree stands into the treeless space of the tundra. This leads to the formation of gley-podzolic soils under these conditions, which predominate in the soil cover of the northern taiga. In these soils, against the background of gleying, fine clay particles are also transported from the upper soil horizons down the profile. Podburs and dwarf podzols predominate on light-textured rocks.

Soils of the taiga-forest zone. Traditionally, in Russia the taiga zone is divided into northern, middle and southern taiga.

This is true for most of the territory of Russia, except for Western Siberia, where a clear boundary between the northern and middle taiga is not observed both geobotanically and in soil terms. Soil cover varies greatly in the European and Asian parts of the country.

The taiga of the European territory of Russia is characterized by the formation of soils of the podzolic series, in which the removal of silty material from the upper horizons to the middle soil horizons occurs. Due to this process, a bleached horizon of lightweight granulometric composition is formed in the upper part of the profile. The middle horizon (horizon B) is enriched with clay material, which forms films and deposits on soil aggregates and in pores. A clay-enriched (textural) horizon is characterized by yellowish-brown or reddish-brown colors, compactness and a well-defined prismatic structure.

In the northern taiga, with a small amount of solar heat and excess moisture, gleying is observed in the profiles of gley-podzolic soils formed here, associated with stagnation of moisture in the upper horizons. The soil cover also contains peat bog and gleyed soils. Taiga gley soils are represented by quite diverse soils, the common feature of which is either the gleying of the entire profile, or the presence of a pronounced gley horizon lying directly under the peaty forest litter or peat surface horizon. Mineral horizons of gley soils on loamy rocks are usually structureless, waterlogged, with obvious signs of frozen deformations of the soil profile. Illuvial-humus and humus-iron podzols are common on sandy and gravelly rocks. Their peculiarity is the presence of a clearly defined bleached podzolic horizon and an underlying dark or rusty-brown humus-iron horizon. Although podzolic soils and podzols have similarities and therefore were previously included in one type, these two groups of soils differ significantly both in the processes that form them, and in their properties and use.

For vast areas of the middle taiga, podzolic soils are most typical. They form here under spruce, spruce-fir and mixed spruce-birch forests on loamy deposits. Due to the insignificant participation of herbaceous vegetation in the ground cover of middle taiga forests, typical podzolic soils do not have turf and a humus horizon. Directly under the forest floor lies a light, slightly colored so-called. acidic podzolic horizon with leaking humus.

The soil cover of the southern taiga mixed coniferous-deciduous forests is dominated by soddy-podzolic soils, the profile of which contains both humus-accumulative and clarified podzolic horizons (see article Podzolic soils). On loamy rocks they contain 3–5% humus(its content quickly decreases with depth). These soils are characterized by an acidic reaction of the soil solution, with acidity being maximum in the forest litter and in the upper mineral horizons of the soil.

Soddy-podzolic soils constitute the main stock of arable land in non-chernozem regions and, with an appropriate fertilizer system, are successfully used in agriculture for growing a variety of grains, vegetables, fruits and fodder crops.

Podzolic soils are also common in a number of regions of Siberia, but in general these soils are not predominant in the taiga of the Asian part of Russia. In Central and Eastern Siberia, taiga permafrost soils (cryozems) are widespread, the profile of which consists of peaty forest litter, a thin humus or coarse humus horizon, turning into a grayish-brown horizon mixed as a result of freezing and thawing; the lower part of the soil profile is saturated with moisture, in a wet state it is thixotropic, i.e. it liquefies under mechanical influence, and is structureless. The depth of summer thawing does not exceed 1 m. The permafrost-taiga pale soils of the Central Yakut Lowland in the territory of Yakutia are unique. They occupy large areas here under larch forests and are characterized by a poorly differentiated soil profile. Under the upper humus horizon there is a light, yellowish-brown horizon, gradually turning into loess-like carbonate loam. The soil reaction is neutral or slightly acidic in the upper horizons and slightly alkaline in the lower ones. With proper reclamation and fertilization, they are suitable for growing grains, vegetables and herbs.

On sandy rocks rich in mineralogical composition in well-drained conditions, taiga podburs are formed without signs of gleying and podzolization. They are distinguished by the presence of a peaty forest floor, directly under which lies a brown illuvial-iron-humus horizon, which gradually turns into soil-forming rock. There is no brightened podzolic horizon in their profile.

In the Middle Urals, in the foothills of the Altai and Sayan Mountains, in the Far East, under the southern taiga, partly and middle taiga forests, peculiar brown taiga soils are common. The profile of these soils is poorly differentiated into genetic horizons. They are distinguished by a high content of humus (up to 7–15%) and mobile iron compounds in the upper horizon, and an acidic reaction of the soil solution. In landscapes with difficult drainage, which promotes stagnation of surface water and the development of the eluvial-gley process, gleyed brown taiga soils are formed.

The volcanic ocher layered-ash soils of Kamchatka are even more unique. A characteristic feature of their genesis is the periodic interruption of soil formation by the fall of new portions of volcanic ash. As a result, their profile consists of elementary profiles superimposed on each other, in each of which organogenic and middle horizons are distinguished; the latter can be colored with humus in coffee tones or with iron hydroxides in ocher tones. Volcanic soils They are distinguished by a light granulometric composition, high water permeability, and a predominance of weakly crystallized aluminosilicate and ferruginous minerals. The reaction of volcanic ocher soils is acidic, the cation absorption capacity is low. The use of these soils in forestry is effective.

Huge areas in the northern regions of Russia, especially in Western Siberia and the Far East, are occupied by marsh soils. They are excessively wet throughout the year and are therefore characterized by slow decomposition of plant residues, which leads to the formation of a peat layer.

Peat soils are divided according to the thickness of the peat deposit, the botanical composition of the peat, the content of the mineral part (ash part) and the degree of decomposition of organic residues. Bog lowland and high peat soils are fundamentally different. Low-lying peatlands are formed when flooded with mineralized groundwater, they have a high ash content, peat is composed mainly of sedges and wood, the degree of decomposition of organic residues is high, the reaction of the environment is slightly acidic or neutral. Raised peat soils are formed when saturated with low-mineralized rainwater: the ash content of peat is low, it is composed predominantly of weakly decomposed sphagnum mosses, and the reaction of the environment is acidic.

Bog lowland soils can be used in agriculture only after drainage reclamation, bog upland soils are suitable only for forestry. Although the soil types prevailing in the northern and middle taiga zones are practically unsuitable for use in agriculture, their importance is extremely high, since they serve as the basis for the growth and development of forests. Peat-bog soils and peat deposits in these natural zones largely determine the hydrological regime of the northern territories and store huge amounts of carbon and nitrogen stored in the form of organic matter.

On carbonate rocks in Central and Eastern Siberia, soddy-carbonate soils are common (see Rendzins) with a slightly acidic or slightly alkaline reaction, a high humus content (up to 5–12%); They are rich in plant nutrients, but, as a rule, have little thickness and are leached or podzolized to varying degrees. In conditions of a humid, cool climate in the subzones of the northern and middle taiga, humus-carbonate soils are formed on carbonate rocks, which differ from sod-carbonate soils by an even higher humus content (up to 20% or more).

In floodplains and river deltas under water meadows they are common alluvial soils, formed under conditions of periodic flooding and accumulation of river sediments (alluvium). Vast spaces are occupied by alluvial soils along the great rivers of Siberia and the Far East: the Ob, Yenisei, Lena and Amur. They are diverse in regime, structure and properties depending on the composition of alluvium, location in one or another area of ​​the river floodplain, as well as on the geographical location of the floodplain itself. In the forest zone, the soils of river floodplains are characterized by an acidic reaction, a relatively high content of organic matter, gleying in the soil profile of the low floodplain and waterlogging in the near-terrace floodplain.

Broad-leaved and coniferous-deciduous forests in the south of the Far East, as well as the mountain slopes of the Caucasus, Altai and Sikhote-Alin, are characterized by brown soils with weak differentiation of the soil profile and a brown color, which is created due to the accumulation of iron oxides and hydroxides. The reaction ranges from slightly acidic to neutral. The humus content in the upper, usually well-structured horizon is up to 10% or more. The moderately warm and humid climate determines the richness and diversity of soil biota. Under different conditions of relief and composition of soil-forming rocks, signs of podzolization or surface gleying appear in brown soils. On leveled, poorly drained areas, there are podbels, characterized by a sharp differentiation of the soil profile: under the humus horizon there is a white or light gray horizon with a lumpy-platy structure and an abundance of ferro-manganese concretions.

Almost all soils in the taiga-forest zone are characterized by low natural fertility and require the application of organic and mineral fertilizers, including liming to reduce soil acidity. In the northern and middle taiga, the main focus of agriculture is dairy and beef cattle breeding, so the soils are used for growing perennial grasses and pastures. Vegetable growing is developing successfully in some places. In the southern taiga, the use of soils in agriculture is expanding significantly: crops such as rye, oats, barley, and buckwheat are cultivated. The main problems in the development and use of soils in the taiga zone are their acidification in the absence of regular liming, depletion due to insufficient application of fertilizers, flooding due to disruption of groundwater hydrology, as well as water erosion. Drained peat soils are characterized by accelerated peat degradation.

Gray forest soils are traditionally divided according to increased humus content and decreased podzolization into light gray, gray and dark gray forest soils. The entire type of gray forest soils is characterized by a higher humus content compared to soddy-podzolic soils, from 2–3% in light gray soils to 8% or more in dark gray soils, and a nutty structure, for which they were previously called nut soils. Gray, especially dark gray, forest soils are fertile. They grow winter and spring wheat, sugar beets, corn, potatoes, flax, etc. To preserve and increase the fertility of gray forest soils, it is necessary to combat water erosion, grass sowing, and systematically use organic and mineral fertilizers, taking into account significant differences in the bioclimatic conditions of different provinces and areas of the forest-steppe zone.

In the forest-steppe and steppe natural zones, large areas are covered by chernozems, deep, dark-colored humus soils. Chernozems are characterized by a neutral reaction, high absorption capacity, and favorable agrophysical properties, largely due to the water-resistant cloddy-granular structure of the humified part of the profile. They are very diverse and are divided according to the zonal principle into forest-steppe (podzolized, leached, typical) and steppe (ordinary and southern). Typical chernozems are characterized by a dark, almost black color, high, up to 10–12%, humus content, a large thickness of the humus horizon, reaching 80–100 cm or more, a gradual decrease in the amount of humus down the profile and the presence of a horizon with various forms of newly formed calcium carbonates . Podzolized and leached chernozems form large areas to the north of the typical ones and are distinguished by weak eluvial-illuvial differentiation of the profile in terms of clay content and a lower level of occurrence of the carbonate horizon. On the loamy and clayey plains of the steppe zone, ordinary and southern chernozems dominate, having a humus horizon 40–80 cm thick; carbonate new formations are represented by white-eye - weakly cemented carbonate concretions in the form of rounded white spots - eyes with a diameter of 1–2 cm. The humus content is 5–8% in ordinary and 3–6% in southern chernozems. According to provincial characteristics, i.e., according to the forms of carbonate release, reflecting the water regime, chernozems are divided into mycelial-carbonate, cryogenic-mycelial, powdery-carbonate, etc.

In the Ciscaucasia, on the Azov-Kuban plain, ordinary and southern mycelial-carbonate chernozems are common. They are distinguished by a large thickness of the humus horizon (up to 120 cm or more); carbonates appear in the upper part of the humus horizon or from the surface. In the steppe Crimea, southern and mycelial-carbonate chernozems are developed on loess; in the west of the peninsula and at the foot of the northern slopes of the Crimean Mountains, residual carbonate chernozems are widely represented on dense carbonate rocks, and on the Kerch Peninsula, on saline clays, fused chernozems are widespread.

Among the chernozem soils, along lower relief elements and with close groundwater (2–5 m), there are meadow-chernozem and chernozem-meadow soils. Meadow-chernozem soils are even darker than chernozems; they are distinguished by a greater thickness of the humus layer and gleyiness of the lower horizons. In contrast, chernozem-meadow soils are characterized by more intense gleyization, a higher groundwater level and a lower thickness of the humus layer. Meadow-chernozem soils are highly fertile, with the exception of solonchakous and solonetzic soils.

The dry steppe zone is dominated by chestnut soils, which contain less humus than chernozems: from 2 to 5%. In addition, they have a smaller humus horizon thickness (from 15 to 50 cm) and a higher carbonate horizon; gypsum appears at the bottom of the profile. They are often solonetzic and compacted.

Chestnut soils are divided into subtypes based on humus content and a number of other properties: dark chestnut, chestnut and light chestnut, the latter being found mainly in semi-deserts. Dark chestnut and chestnut soils are plowed over a large area and used for growing grain crops.

Among the chestnut soils along the depressions of the relief there are meadow-chestnut soils, which differ from chestnut soils only in greater humus content and better moisture supply. Meadow-chestnut soils most often form complexes with chestnut soils, salt licks and salt marshes.

In the steppe and dry-steppe zones, and to a lesser extent in the forest-steppe, significant areas are occupied by saline soils containing easily soluble salts in the surface horizon or throughout the entire profile; Salinization processes manifest themselves to an even greater extent in semi-deserts.

The processes of salt accumulation in soils are most clearly expressed in solonchaks. These soils contain more than 1–2% of readily soluble salts in the surface horizon. Based on the composition of salts, solonchaks are divided into chloride, sulfate, soda and mixed (chloride-sulfate, sulfate-chloride, etc.), and based on the composition of cations - sodium, magnesium, calcium.

Agricultural use of salt marshes is possible only if radical reclamation is carried out, and the most effective is reclamation leaching, which removes salts from the soil and drains them into the drainage system.

Solonchak soils differ from solonchaks in their lower content of easily soluble salts. They are divided into highly, moderately and slightly saline. Saline soils are adjacent to solonetzes - alkaline soils that do not contain easily soluble salts or contain them not in the upper horizons, but at some depth. The alkaline reaction is due to the high content of exchangeable sodium in soils. Their upper humus-accumulative horizon is replaced by a columnar, very dense, clay-enriched solonetz horizon with an alkaline reaction; below it passes into a subsolonetz nutty horizon with carbonates and gypsum. Solonetzes are widespread mainly in dry semi-desert steppes, as well as in steppe and even forest-steppe zones. Most often they are found as part of the so-called. solonetz complexes, including solonchaks, solonchaks, meadows, chestnut soils or chernozems.

Malts are genetically related to solonetzes and solonetzic soils. They are formed under the influence of stagnant moisture and leaching of salts from the soil profile. Malts are common under birch stakes in the forest-steppe of Western Siberia; They are also found in saucer-shaped depressions in steppes and forest-steppes. A characteristic feature of malt is a sharp differentiation of the soil profile into genetic horizons with the obligatory inclusion of a light horizon with ferromanganese nodules and the presence of a dense brown-brown illuvial horizon underneath it. Light-colored solodized horizons are characterized by a slightly acidic reaction; residual accumulation of silica is also noted.

The soils of the forest-steppe, steppe and dry-steppe zones represent the basis of the country's soil fund for agricultural needs, which is associated with both optimal climatic conditions and high natural soil fertility. The soils are used for winter and spring wheat, corn, sunflowers, soybeans, vegetables and horticultural crops. The development of chernozems is maximum: almost all soils of the chernozem zone, with the exception of settlements, inconveniences and specially protected areas, are plowed and used in agriculture. Chestnut soils are also predominantly plowed; Some chestnut soils are used for grazing. In the steppe and dry steppe zones, both chernozems and chestnut soils in some places require drip irrigation. The development and agricultural use of solonetzes is possible, but requires a whole system of reclamation and agrotechnical measures, including gypsum, special deep plowing followed by grass sowing.

Semi-desert soils. In Russia, semi-deserts occupy a relatively small area, mainly within the Caspian lowland. There, on ancient alluvial sands and loamy loess-like deposits, brown desert-steppe soils(semi-desert) - low in humus, thin, dense and often solonetzic. The amount of humus in them rarely exceeds 1.5–2.0%, the thickness of the humus horizon is no more than 10–15 cm, below there is a dense brownish-brown horizon, which in turn is replaced by an illuvial carbonate horizon; at a depth of 80–100 cm there are accumulations of gypsum, under which easily soluble salts are found. Along the depressions of the relief, under forb-grass vegetation, there are meadow-brown soils that are characterized by higher humus content. The soil cover of the semi-desert zone is characterized by diversity with frequent alternation of soils - light chestnut, brown desert-steppe, solonetzes and solonchaks.

The soil cover of the semi-desert zone is favorable for the development of pasture animal husbandry, and in depressions with meadow-chestnut and meadow-brown soils - melon growing. When irrigating them, careful monitoring of soil conditions is necessary in connection with the possible development of secondary salinization. Overgrazing by livestock leads to rapid degradation of pastures, desertification and over-compaction of the upper soil horizons.

Subtropical soils. Subtropical soils are represented in Russia by yellow soils and brown soils. Yellow soils occupy a narrow strip of land along the Black Sea coast in the Tuapse - Sochi region; they are characterized by an increased content of mobile oxides of iron, aluminum and manganese. Their profile includes a leached yellow horizon with an acidic reaction environment, passing down into an illuvial light yellow horizon with a large number of ferromanganese nodules.

Yellow soils are used for growing tea, citrus fruits, fruits and vegetables, but require organic and mineral fertilizers, as well as protection from water erosion.

Brown soils are common in mountainous Dagestan and in the south of the Crimean Peninsula under dry sparse forests and thickets of bushes with grass cover in a warm and dry subtropical climate. They distinguish between a humus horizon (brownish-gray in color with a lumpy-grained structure, containing 4–6% humus), a transitional brownish-brown lumpy-nutty clay horizon, and a lighter horizon with the release of calcium carbonates in the pores.

Brown soils are used for orchards and vineyards and need protection from water erosion.

Mountain soils. Mountain soils occupy more than 1/3 of the country's total area. These include the soils of the mountainous territories of Crimea, the Caucasus, the Urals, Altai, Eastern Siberia and the Far East. The soil cover of the mountains is characterized by high complexity. Compared to flat mountain soils, they are distinguished by a smaller vertical profile, good drainage, and high gravelly and stony content. The soil cover of mountains is characterized by an abundance of soils disturbed as a result of slope processes, such as landslides, landslides, mudflows, surface and gully erosion. Most mountain soils can be attributed to the corresponding soil types formed on the plains. Some types can be considered as specifically mountainous: for example, mountain-meadow and mountain meadow-steppe soils have no analogues on the plains. Mountain meadow soils are formed in humid climates under well-developed grass cover. They have developed turf and humus horizons (humus content is up to 20%) with a lumpy-grained structure; these soils are characterized by an acidic reaction throughout the profile. Mountain meadow-steppe soils are drier, have less humus, and are neutral.

Mountain forest soils are of great importance in the country's forestry, as well as in environmental protection. When mountain forests are cut down, their soil cover is quickly subject to erosion, which entails drifts and river pollution, floods in adjacent areas, and disruption of the hydrological regime in large areas of river basins. Mountain meadow and mountain meadow-steppe soils are used in pasture farming. They need anti-erosion protection.

Anthropogenically transformed and anthropogenic soils. The natural diversity and condition of soils is significantly impacted by industrial, mainly agricultural, human activities. The structure, properties, regimes of soils change and transform to varying degrees, artificial soils are created, etc. Specialists of the Soil Institute named after. V.V. Dokuchaeva developed a new classification of soils in Russia (2004), taking into account the degree of their anthropogenic transformation. In this classification, those soils that have been significantly altered by humans, but have not lost the characteristics of the original natural soils, are identified as anthropogenically transformed. The name of such soils is formed by adding the component “agro-” to the names of natural soil types; for example, agropodzolic soils, agrochernozems, etc. If natural soils are so altered that they do not retain typical characteristics or are completely artificially created, then they are classified as anthropogenic. This agrozems(soils completely changed in the process of cultivation), stratozems (bulk soils), etc.

Patterns of soil distribution. The distribution of soils on the territory of Russia shows geographic patterns associated with the combined influence of bioclimatic and geological-geomorphological factors of soil formation. These patterns are reflected in the system of soil-geographical zoning of the Russian Federation (Dobrovolsky, Urusevskaya, 2006). In accordance with this system, polar, boreal, subboreal and subtropical soil-bioclimatic zones are distinguished on the territory of the country, and within them - soil-bioclimatic regions and facies, soil zones, subzones and provinces. In the direction from north to south, zones of arctic and tundra soils, podzolic taiga, gray forest, forest-steppe and steppe chernozems, chestnut dry-steppe, brown semi-desert, subtropical brown and yellow soils are distinguished.

On the territory of Russia, according to the degree of continental climate, 4 soil-bioclimatic facies are clearly distinguished: European temperate continental, West Siberian continental, East Siberian extracontinental and Far Eastern monsoon. The territories of these facies are so different in other natural features, such as relief, soil-forming rocks and geological history, that they can be considered not only special bioclimatic facies, but also special soil-geological countries.

The totality of the influence of bioclimatic and geological-geomorphological factors in each of the identified facies, including segments of latitudinal soil zones, determines the characteristics of the soils and soil cover structures common in them.

The European temperate continental facies is characterized by a clearly defined latitudinal zonal structure of the soil cover; The West Siberian continental facies differs from it by a much wider distribution of gleyed, bog, peat and peat-gley soils in the taiga zones, meadow, meadow-chernozem, solonetzic, solodized and saline soils in the forest-steppe and steppe zones. The East Siberian extracontinental facies is characterized by the widespread distribution of permanently frozen soils and associated cryogenic processes in soils. The latitudinal zonation of the soil cover is weakly expressed in it. In mountainous terrain on dense sedimentary and massively crystalline rocks, various gravelly thin tundra and taiga permafrost soils predominate. On the weathering products of traps and on carbonate rocks, non-podzolized soils such as soddy-carbonate, taiga podburs, granuzems with a structure in the form of rounded granules, humified soils and enriched with mobile iron compounds without signs of podzolization are formed. The Far Eastern monsoon soil-bioclimatic facies is characterized by a wide variety of soils formed under conditions of lowland and mountainous soil formation. Due to the meridional elongation of the territory of this facies along the Pacific coast from Chukotka to the south of Primorsky Krai, the latitudinal zonation of soils is clearly expressed, but in the form of relatively small sections of soil-geographic zones of tundra, northern, middle and southern taiga and coniferous-deciduous forests. A common feature of the soils of the Far Eastern monsoon facies, both in the north and in the south, is their high humidity, so tundra-swamp, peat-swamp, sod-gley, brown-taiga gley, podbel, meadow-swamp, meadow-chernozem-like (“chernozem”) are widespread here. Amur prairies") soils.

The Kamchatka Peninsula represents a unique soil province, where soil formation occurs under conditions of active volcanic activity.

Latitudinal bioclimatic zoning is manifested in the geography of soil cover not only in the form of flat soil zones, but also in the different structure of the vertical zonality of mountainous countries, depending on their geographical location. For example, the system of vertical zoning of the Northern Urals is represented by only three altitudinal belts: the lower northern taiga dark coniferous with gley-podzolic soils and taiga podburs, the middle belt of tundra-gley and tundra podburs and the upper alpine belt of primitive mountain soils and rocky placers. In the structure of the vertical zonation of the Middle Urals in the lower zone under the middle taiga spruce and spruce-fir forests, podzolic soils predominate, on average - brown taiga soils; higher up they give way to mountain-meadow soils, and then tundra podburs. The vertical zonation of the Southern Urals is represented by six vertical belts. The lower zone at the southern end of the mountain range is formed by forest-steppe with gray forest soils, among which leached chernozems appear along intermountain depressions and slopes of southern exposure. Above is a belt of broad-leaved forests with gray forest soils, which, as the absolute altitude increases and humidity increases, is replaced by a coniferous-broad-leaved belt with brown earth soils, and then a belt of dark coniferous forests with brown taiga mountain soils; even higher is a belt of mountain meadows with mountain meadow soils. At an altitude of approx. At 1500 m, mountain meadows turn into mountain tundra with tundra podburs and tundra peaty-gley soils (see Fig. 1).

The specificity of the vertical zonation of soils in the mountains depends not only on the latitude of the area, but also on the location of the mountain range in relation to the dominant direction of atmospheric circulation, slope exposure, and other factors. Thus, on the western Black Sea slope of the Greater Caucasus in the Sochi-Tuapse region, the lower mountain belt is represented by a humid-subtropical landscape with yellow earth soils, passing higher into a belt of broad-leaved and coniferous-deciduous forests on brown soils. On the eastern part of the slope of the Greater Caucasus to the Caspian Sea, the lower zone is represented by various dry forests and shrubs of the Mediterranean type on mountain-brown soils, and even higher - mountain-meadow and mountain-steppe soils. Rice. Figure 2 illustrates the influence of exposure on the structure of the vertical zonality of the Tannu-Ola ridge (Tuva Republic).

Along with the geographical patterns of soil distribution, determined primarily by bioclimatic factors, the geological and geomorphological conditions of soil formation are no less significant. They determine the quantitative relationships and spatial arrangement of plain and mountain soils, the isolation of mineralogical and geochemical soil provinces and geological and geomorphological soil districts and regions, the granulometric composition of parent rocks and soils, and the formation of special lithogenic soil types. The latter are formed in cases where soil-forming rocks have a decisive influence on the genesis and properties of soils. These are soddy-carbonate soils (rendzins), found in different bioclimatic zones, and ocher volcanic soils, formed under the direct influence of volcanic ash.

The characteristics of soils in Russia are given in accordance with the legend of the new Soil Map of Russia (2017, scale 1:15,000,000).

Methods for cultivating the soil and preparing it for planting fruit and berry plants depend on the type of soil and underlying soil. The soils of the Non-Black Earth Region are very diverse due to the heterogeneity of soil-forming rocks, diversity of relief and climatic conditions.

Soil structure

The predominant soils are podzolic type, the natural fertility of which is usually low. Each type of soil has a characteristic structure. The elements of the profile structure are soil horizons, indicated by letter symbols.

Here are the main ones:

• A – upper humus (humus) layer, usually dark in color, most favorable for root growth;
• B – transitional from humus to parent rock;
• C – parent soil-forming rock.

You can see the structure of the soil on the walls of the soil section. Soddy-podzolic soils are characterized by a shallow humus horizon (12-18 cm) and the presence of a whitish or brown podzolic layer. It is formed as a result of the leaching of organic matter - it is sterile, structureless, and often contains a large amount of elements harmful to plants. Plant roots do not grow in the podzolic horizon.

Determining the degree of podzolization of the soil is of practical importance: in slightly podzolized soils the podzolic horizon is 2-5 cm, in moderately podzolized soils it is 6-14 cm, in strongly podzolized soils it is 15-30 cm or more.

Lightly podzolized soils can be cultivated in one step by digging with the addition of manure or compost. If there is a large layer of podzol, it is necessary to gradually incorporate the podzol into the topsoil.

The transition horizon (B), predominantly brown in color, may be heterogeneous. Soil quality is influenced by parent rock (C). It can be clay, loam, sandy loam, sand (boulder or non-boulder); two-layer sediment (sandy loam and sand are underlain by clay or loam). Uncultivated soddy-podzolic soil contains little potassium and phosphorus and is highly acidic.

They are widespread in the area soils of varying degrees of swampiness. They are rich in phosphorus and nitrogen, but become suitable for planting only after drainage and subsequent cultivation. Under conditions of waterlogging, a large amount of poorly decomposed plant residues of a characteristic bluish or greenish color accumulate in the upper horizon of these soils. The properties of soils, their water permeability, moisture capacity, air and thermal regimes, and supply of nutrients largely depend on the mechanical composition, i.e. the size of their constituent particles. On this basis soils are divided into clayey, loamy, sandy loam and sandy.

A simple field method can be used to determine the mechanical composition of the soil. To do this, take a little soil and moisten it until it becomes a thick paste. Then they knead and roll out a cord about 3 mm thick on the palm, which is rolled into a ring and a conclusion is made based on its appearance.

Main soil types

Clay soils

Clay soils (consisting of silty and dusty particles) are dense, poorly permeable to water (about 30% of summer precipitation penetrates), contain little air, and beneficial microbiological processes weakly occur in them.

• Clay soils retain up to 20% of water in a state inaccessible to plants, do not warm up well, but they contain more nutrients than light soils.
• They need to be loosened and dug up frequently in spring and autumn.
• To improve the physical and mechanical properties of heavy soils, add a lot of manure, compost or peat. It is effective to add sand (sanding) or slag for digging.

Sandy loam and sandy soils

Sandy loam and sandy soils consist mainly of sand and silt.

• They weakly retain moisture, and along with it, nutrients are washed into the lower layers.
• They warm up quickly, but dry out greatly, so they require additional watering.
• Typically, sandy loam soils are low in potassium and magnesium. To increase fertility and improve the structure of such soils, organic and mineral fertilizers are applied to them fractionally, in smaller doses in spring and autumn; loosened less often than dense soils.
• For cultivation, leguminous grasses are sown, which during the budding period are buried in the soil as green fertilizer.

One of the methods for improving sandy soils is to lay layers of peat and compost mixed with clay in the soil. Such layers are laid along the planting line to a depth of 50-60 cm. In deep sand, wide trenches or holes are dug with a diameter of 1-2 m, a depth of up to 0.8-1 m, but not deeper than the groundwater level in the spring. Clay mixed with sand or peat (3 parts clay and 1 part sand or peat) is placed on the bottom in a layer of 5-10 cm.

Loamy soils

— in terms of mechanical composition and properties, they occupy an intermediate position; they are most favorable for garden crops. Light loamy soils lend themselves well to cultivation.

Differences between peat bogs and mineral soils

The above soils are classified as normal mineral soils. But there are also peat soils that are divided into lowland, upland and transitional.

Lowland peatlands

- located in river valleys, near lakes, in lowlands, where a large amount of nutrients are carried here with the flow of surface and groundwater. They are formed with the participation of abundant vegetation. Therefore, peat is rich in nutrients, well decomposed, slightly acidic or neutral, and often does not require liming.

High peat bogs

- Formed in elevated areas. They are formed mainly due to sphagnum mosses and atmospheric precipitation. The peat of raised bogs is slightly decomposed, brown in color, poor in nutrients, and very acidic. The development of high peat bogs is less effective than lowland peat bogs.

Transitional peatlands

- occupy an intermediate position between lowland and upland. The peat of such bogs is characterized by low ash content and a slightly acidic reaction.

Peat soils are fundamentally different from mineral (ordinary) soils. This difference is explained by the predominance of organic matter in them (50-70% in low-lying peats, 80-90% in high-moor peats), which is many times more than in ordinary soils.

• Peat has increased moisture capacity. Lowland peat can absorb 5-7 times, and high-moor peat 10-15 times more than its dry mass (the soil retains 20-50% of its mass of water).
• Peat soils have low thermal conductivity and are therefore considered “cold”; they thaw and warm up very slowly in the spring, which delays the start of agricultural work by 10-14 days. In autumn, early frosts lead to the cessation of plant growth earlier than on conventional soils.

Peat does not contain microorganisms harmful to plants. It is potentially fertile, however batteries are found in tightly bound compounds that are inaccessible to plants. Of the main nutrients, peat contains nitrogen in significant quantities. As it decomposes, micro- and macroelements accumulate in peat. To accelerate the decomposition of peat and to activate biological processes, small doses of manure and fecal compost are added.

As a rule, when caring for plants propagated on peat bogs, higher doses of potassium and phosphorus are used than on ordinary soils. Of the microfertilizers, the most important is the use of copper, boron and molybdenum fertilizers.

Gardens can also be used exhausted peatlands. Peat quarry soils differ in their underlying rocks. All types of dark-colored peat bogs, underlain by limestone, have a rich humus horizon and a slightly acidic or neutral reaction. They do not need liming.

Peatlands underlain by sandy or sandy loam soil have a podzolic horizon and a slightly acidic or acidic reaction. Exhausted high peat bogs have a weakly pronounced humus layer and are acidic.

Peat bogs with a layer of 40-50 cm are considered the most suitable for cultivating a garden. However, even with a layer of 10-15 cm, you can deepen the soil by mixing it with 2-5 cm of underlying soil.

During development, peatlands are limed, and organic and mineral fertilizers and bacteriological preparations are added to stimulate microbiological processes. By draining excess water, the groundwater level is reduced. It is difficult to grow fruit on peat bogs due to the proximity of groundwater and the increased frost danger of the terrain, but berry bushes grow well, and strawberries grow successfully.

When growing berry crops on peat, you should pay attention to the density of the soil. If it is very loose, then the plants develop poorly. To eliminate this drawback, sand or clay is added to drained peat soils. 4 buckets of sand or 2 buckets of clay are scattered over the surface at the rate of 1 sq.m of low-lying peatland; for high peat bog - 5 buckets of sand or 3 buckets of clay. Then the area is dug up on the bayonet of a shovel.

Soil containing a lot of gravel or substances harmful to plants is not desirable. When sanding or claying on peat bogs, the root layer warms up better, and the duration of the period with optimal temperatures is significantly extended (by 50 days or more).

Interesting on the topic

Soil is an integral part of the kingdom of nature and plays a large role in the existence of all life on our planet. It is in it that the interaction of all the shells of the Earth takes place - water, air, underground.


The most valuable characteristic of this natural formation is fertility, which provides vegetation with moisture and essential nutrients. What is soil? What does it consist of and what is its significance for life on the globe?

What is soil?

The most complete and extensive study of the soil was carried out by the Russian geologist Vasily Dokuchaev, who discovered the most important patterns in its genesis and geographical distribution. According to his theory, soil is a special natural body that is formed due to the influence of several factors - the climatic characteristics of a particular region, the nature and age of the soil, and the vegetation growing on it.

In a more modern understanding, soil is the top layer of the planet, formed through the activity of living organisms and weathering of rocks. In different regions of the globe, the thickness of this layer ranges from a few centimeters to 2–3 meters.


The composition of the soil may vary depending on its depth. If you dig a hole in the ground, you will notice that more fertile black soils are located on top, and below are the so-called parent rocks, from which the top layer is formed.

What is soil made of?

The soil has a heterogeneous structure and includes particles of different rocks with a diameter from 0.001 millimeters to several centimeters. As for the mineralogical composition, it may vary depending on its state - solid or liquid. In solid soil, about 50–60% of the volume is occupied by mineral components, such as feldspars, quartz, zircon, and kaolinite.

Hydroxides of iron, manganese, aluminum, and carbonates play a significant role in soil formation. In addition to minerals, solid soil contains organic substances - humus, plant and animal residues. Liquid soil is a solution in which, in addition to the above components, water is present in large quantities.

How is soil formed?

Conventionally, the process of soil formation can be divided into primary and anthropogenic. In the primary phase of soil formation, the interaction of objects of organic and inorganic nature occurs.


In other words, initially it consists of humus and mineral substances, subsequently its voids are filled with soil air, living organisms settle in it, which, after death, decompose and enrich the existing composition with organic substances.

The anthropogenic process involves human economic activity. People cultivate the soil, plant crops in it, and add fertilizers to get a good harvest.

What types of soils are there?

Depending on the predominance of one or another soil-forming factor, soils can be divided into chernozem, chestnut, forest, podzolic or weakly podzolic, tundra and many others.

Vasily Dokuchaev identified 10 types of topsoil, but today more than a hundred of them are known. To classify soils, there is a whole hierarchy, which includes not only types, but also subtype, genus, species, and category.

Who lives in the soil?

Soil is a fertile habitat for a huge number of living organisms. All creatures that live in the upper layer of the earth are called pedobionts. These include both single-celled organisms, fungi, bacteria or algae, as well as larger representatives of fauna - earthworms, beetles, spiders. Most soil inhabitants feed on the remains of rotten plants or mycelium.


There are also vertebrate animals in the soil, such as moles. It is ideally adapted for living in the dark, so it has excellent hearing and virtually no vision. In addition to moles, among mammals the soil is home to mole rats, mole rats, and mole rats.

Some animals, such as gophers, jerboas and badgers, feed on the surface of the earth, and hibernate in the soil, reproduce and escape from enemies.