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The main types of soils by latitudes. Natural zones of Russia: Brief description of the zones

Clean water, air and solar energy are the fundamental conditions for life on the globe. A wide variety of climatic zones led to the fact that the continents were divided into natural zones: some of them are very similar to each other, others are unique and unrepeatable. Consider what soils are characteristic of the natural zone for a particular climatic zone.

Natural areas of the world

Natural zones are natural complexes that occupy large areas and are characterized by a common type of landscape. Climate has a great influence on their formation, with the peculiarities of the ratio of moisture and heat.

The main characteristic of any natural area is the unique plants and animals that inhabit this area, but, above all, the unique composition of the soil.

The structure of the soil, the features of its origin and the level of fertility underlie the soil classification.

Table "Soils and natural areas"

*natural area*	*Soil types*		*soil properties*	*soil formation conditions*
Arctic deserts	arctic	Very few	barren	Little heat and vegetation
	Tundra-gley		Low power, gel layer	Permafrost, little heat, waterlogging
forest zone A) Taiga of the European part	Podzolic		Flushing, acidic	K>1, plant residues - needles
B) Taiga of Eastern Siberia	taiga-permafrost		Infertile, cold	Eternal Frost
B) mixed forests	Sod-podzolic	More than in podzolic	More fertile	Flushing in the spring, more plant residues
D) Broad-leaved forests	gray forest		More fertile
	Chernozems, chestnut		The most fertile	K = 1, a lot of plant residues, a lot of heat
semi-deserts	Brown, gray-brown	less humus	Soil salinization	Dry climate, sparse vegetation, K<0.5

Features of the main types of soils

Depending on belonging to a certain climatic zone, the following types of soils are distinguished:

Soils of the tundra zone.

This zone is dominated by the tundra-gley type of soil, which was formed under poor rainfall and low temperatures. The soil warms up only on the surface, and at a depth there is only frozen ground.

Constant cold does not allow moisture to fully evaporate, which is why excess moisture accumulates on the surface of the earth. It is not surprising that vegetation in the tundra zone is very poorly developed. It is dominated by mosses, lichens, a few dwarf trees and shrubs.

Rice. 1. The vegetation of the tundra is very scarce.

In this climatic zone you will not find forests, and this is explained by the very word "tundra", which translates as "forestless".

Soils of the taiga-forest zone.

It is characterized by podzolic, gley-podzolic and soddy-podzolic soils - as a rule, acidic, very wet, with a small content of humus. The climate is moderately cold and quite humid, contributing to the spread of swamps and forests.

Humus is the most important component of the soil, organic matter containing all the nutrients necessary for the development of plants.

Rice. 2. Humus is the basis of soil fertility.

Soils of the forest-steppe zone.

They are divided into leached and podzolized chernozems, brown forest and gray forest soils. Due to the significant content of humus, they are moderately fertile, and the relatively warm and humid climate creates favorable conditions for forests interspersed with steppe areas.

Soils of the steppe zone.

Due to the deep layer of humus, this zone is dominated by the most fertile soil - chernozem. The mild climate and the absence of frosty winters make it possible to grow many crops, however, to obtain high yields, it is necessary to provide abundant moisture. The vast majority of the territory of the steppe zone is occupied by plains.

Rice. 3. Chernozem is the most fertile type of soil.

Soils of the dry steppe zone.

The predominant soils are chestnut. There is enough humus in them, but the arid climate with rare and scarce rainfall causes strong evaporation of moisture from the surface of the earth. To maintain a stable yield in such a zone, regular and very plentiful watering is necessary.

Soils of the semi-desert zone.

The zone is represented by brown arid soils with high salinity and erosion. The low content of humus causes low fertility, and this is also facilitated by an extremely arid climate with insufficient rainfall.

Soils of dry subtropics

Soils characteristic of this zone are gray soils, which are determined by a low concentration of humus. The climate is very hot and dry.

Soils of humid subtropics

A characteristic type of soil is krasnozems, in which the deficiency of nitrogen and phosphorus is especially acute. The humus content is negligible.

This climatic zone is characterized by a stable temperature throughout the year, high humidity and an abundance of precipitation.

Soils of river floodplains.

The main characteristic feature of floodplain soils is their frequent flooding by nearby rivers. The concentration of humus in them can be very high, but uneven.

What have we learned?

The emergence of various natural zones became possible due to the climate. As a result, not only the flora and fauna of these territories began to differ, but also the composition of the soil. Its changes are related to which of the natural zones is dominated by humidity and heat.

For the horizons, a letter designation is adopted, which makes it possible to record the structure of the profile. For example, for sod-podzolic soil: A 0 -A 0 A 1 -A 1 -A 1 A 2 -A 2 -A 2 B-BC-C .

The following types of horizons are distinguished:

Organogenic- (litter (A 0, O), peat horizon (T), humus horizon (A h, H), sod (A d), humus horizon (A), etc.) - characterized by biogenic accumulation of organic matter.
Eluvial- (podzolic, glazed, solodized, segregated horizons; denoted by the letter E with indices, or A 2) - characterized by the removal of organic and / or mineral components.
illuvial- (B with indices) - characterized by the accumulation of matter removed from the eluvial horizons.
Metamorphic- (B m) - are formed during the transformation of the mineral part of the soil in place.
Hydrogen storage- (S) - are formed in the zone of maximum accumulation of substances (highly soluble salts, gypsum, carbonates, iron oxides, etc.) brought by groundwater.
Cow- (K) - horizons cemented by various substances (highly soluble salts, gypsum, carbonates, amorphous silica, iron oxides, etc.).
gley- (G) - with prevailing reducing conditions.
Subsoil- parent rock (C) from which the soil was formed, and underlying underlying rock (D) of a different composition.

Soil solids

The soil is highly dispersed and has a large total surface of solid particles: from 3-5 m² / g for sandy soils to 300-400 m² / g for clay soils. Due to the dispersity, the soil has significant porosity: the pore volume can reach from 30% of the total volume in waterlogged mineral soils to 90% in organogenic peat soils. On average, this figure is 40-60%.

The density of the solid phase (ρ s) of mineral soils ranges from 2.4 to 2.8 g / cm³, organogenic: 1.35-1.45 g / cm³. Soil density (ρ b) is lower: 0.8-1.8 g/cm³ and 0.1-0.3 g/cm³, respectively. Porosity (porosity, ε) is related to densities by the formula:

ε = 1 - ρ b /ρ s

The mineral part of the soil

Mineral composition

About 50-60% of the volume and up to 90-97% of the mass of the soil are mineral components. The mineral composition of the soil differs from the composition of the rock on which it was formed: the older the soil, the stronger this difference.

Minerals that are residual material during weathering and soil formation are called primary. In the zone of hypergenesis, most of them are unstable and are destroyed at one rate or another. Olivine, amphiboles, pyroxenes, and nepheline are among the first to be destroyed. More stable are feldspars, which make up up to 10-15% of the mass of the solid phase of the soil. Most often they are represented by relatively large sand particles. Epidote, disthene, garnet, staurolite, zircon, tourmaline are distinguished by high resistance. Their content is usually insignificant, however, it makes it possible to judge the origin of the parent rock and the time of soil formation. The most stable is quartz, which weathers over several million years. Due to this, under conditions of prolonged and intense weathering, accompanied by the removal of mineral destruction products, its relative accumulation occurs.

The soil is characterized by a high content secondary minerals, formed as a result of deep chemical transformation of primary, or synthesized directly in the soil. Particularly important among them is the role of clay minerals - kaolinite, montmorillonite, halloysite, serpentine and a number of others. They have high sorption properties, a large capacity of cation and anion exchange, the ability to swell and retain water, stickiness, etc. These properties largely determine the absorption capacity of soils, its structure and, ultimately, fertility.

The content of minerals-oxides and hydroxides of iron (limonite, hematite), manganese (vernadite, pyrolusite, manganite), aluminum (gibbsite) and others is high, which also strongly affects the properties of the soil - they are involved in the formation of the structure, the soil absorbing complex (especially in heavily weathered tropical soils), take part in redox processes. Carbonates play an important role in soils (calcite, aragonite, see carbonate-calcium balance in soils). In arid regions, readily soluble salts (sodium chloride, sodium carbonate, etc.) often accumulate in the soil, affecting the entire course of the soil-forming process.

Grading

Ferret's triangle

Soils can contain particles with a diameter of less than 0.001 mm, and more than a few centimeters. A smaller particle diameter means a larger specific surface, and this, in turn, means larger values of cation exchange capacity, water-holding capacity, better aggregation, but less porosity. Heavy (clay) soils may have problems with air content, light (sandy) - with water regime.

For a detailed analysis, the entire possible range of sizes is divided into sections called factions. There is no single classification of particles. In Russian soil science, the scale of N. A. Kachinsky is adopted. The characteristic of the granulometric (mechanical) composition of the soil is given on the basis of the content of the fraction of physical clay (particles less than 0.01 mm) and physical sand (more than 0.01 mm), taking into account the type of soil formation.

The determination of the mechanical composition of the soil according to the Ferre triangle is also widely used in the world: on one side, the proportion of silt is deposited ( silt, 0.002-0.05 mm) particles, according to the second - clay ( clay, <0,002 мм), по третьей - песчаных (sand, 0.05-2 mm) and the intersection of the segments is located. Inside the triangle is divided into sections, each of which corresponds to one or another granulometric composition of the soil. The type of soil formation is not taken into account.

Organic part of the soil

The soil contains some organic matter. In organogenic (peat) soils, it can predominate, but in most mineral soils, its amount does not exceed a few percent in the upper horizons.

The composition of the organic matter of the soil includes both plant and animal remains that have not lost the features of the anatomical structure, as well as individual chemical compounds called humus. The latter contains both non-specific substances of a known structure (lipids, carbohydrates, lignin, flavonoids, pigments, wax, resins, etc.), which make up up to 10-15% of the total humus, and specific humic acids formed from them in the soil.

Humic acids do not have a specific formula and represent a whole class of macromolecular compounds. In Soviet and Russian soil science, they are traditionally divided into humic and fulvic acids.

Elemental composition of humic acids (by mass): 46-62% C, 3-6% N, 3-5% H, 32-38% O. Composition of fulvic acids: 36-44% C, 3-4.5% N, 3-5% H, 45-50% O. Both compounds also contain sulfur (from 0.1 to 1.2%), phosphorus (hundredths and tenths of a%). Molecular weights for humic acids are 20-80 kDa (minimum 5 kDa, maximum 650 kDa), for fulvic acids 4-15 kDa. Fulvic acids are more mobile, soluble throughout the entire range (humic acids precipitate in an acidic environment). The carbon ratio of humic and fulvic acids (C HA /C FA) is an important indicator of the humus status of soils.

In the molecule of humic acids, a core is isolated, consisting of aromatic rings, including nitrogen-containing heterocycles. The rings are connected by "bridges" with double bonds, creating extended conjugation chains, causing the dark color of the substance. The core is surrounded by peripheral aliphatic chains, including hydrocarbon and polypeptide types. The chains carry various functional groups (hydroxyl, carbonyl, carboxyl, amino groups, etc.), which is the reason for the high absorption capacity - 180-500 meq / 100 g.

Much less is known about the structure of fulvic acids. They have the same composition of functional groups, but a higher absorption capacity - up to 670 meq/100 g.

The mechanism of formation of humic acids (humification) is not fully understood. According to the condensation hypothesis (M. M. Kononova, A. G. Trusov), these substances are synthesized from low molecular weight organic compounds. According to the hypothesis of L. N. Alexandrova, humic acids are formed by the interaction of high-molecular compounds (proteins, biopolymers), then gradually oxidized and split. According to both hypotheses, enzymes, formed mainly by microorganisms, take part in these processes. There is an assumption about a purely biogenic origin of humic acids. In many properties, they resemble the dark-colored pigments of mushrooms.

soil structure

The structure of the soil affects the penetration of air to the roots of plants, the retention of moisture, and the development of the microbial community. Depending only on the size of the aggregates, the yield can vary by an order of magnitude. The optimal structure for plant development is dominated by aggregates ranging in size from 0.25 to 7-10 mm (agronomically valuable structure). An important property of the structure is its strength, especially water resistance.

The predominant form of aggregates is an important diagnostic feature of the soil. There are round-cubic (granular, lumpy, lumpy, dusty), prism-shaped (columnar, prismatic, prismatic) and slab-like (platy, scaly) structure, as well as a number of transitional forms and gradations in size. The first type is characteristic of the upper humus horizons and causes a large porosity, the second - for illuvial, metamorphic horizons, the third - for eluvial ones.

Neoplasms and inclusions

Main article: Soil neoplasms

Neoplasms- accumulations of substances formed in the soil in the process of its formation.

Neoplasms of iron and manganese are widespread, whose migratory ability depends on the redox potential and is controlled by organisms, especially bacteria. They are represented by concretions, tubes along the root paths, crusts, etc. In some cases, the soil mass is cemented with ferruginous material. In soils, especially in arid and semi-arid regions, calcareous neoplasms are common: plaque, efflorescence, pseudomycelium, concretions, crust formations. Gypsum neoplasms, also characteristic of arid regions, are represented by plaques, druses, gypsum roses, and crusts. There are new formations of easily soluble salts, silica (powder in eluvial-illuvial differentiated soils, opal and chalcedony interlayers and crusts, tubes), clay minerals (cutans - incrustations and crusts formed during the illuvial process), often together with humus.

To inclusions include any objects that are in the soil, but not associated with the processes of soil formation (archaeological finds, bones, shells of mollusks and protozoa, rock fragments, debris). The assignment of coprolites, wormholes, molehills and other biogenic formations to inclusions or neoplasms is ambiguous.

Soil liquid phase

Conditions of water in the soil

Soil is divided into bound and free water. The first soil particles are so firmly held that it cannot move under the influence of gravity, and free water is subject to the law of gravity. Bound water, in turn, is divided into chemically and physically bound.

Chemically bound water is part of some minerals. This water is constitutional, crystallization and hydrated. Chemically bound water can only be removed by heating, and some forms (constitutional water) by calcining minerals. As a result of the release of chemically bound water, the properties of the body change so much that one can speak of a transition into a new mineral.

Physically bound water is retained by the soil by the forces of surface energy. Since the magnitude of the surface energy increases with an increase in the total total surface of the particles, the content of physically bound water depends on the size of the particles that make up the soil. Particles larger than 2 mm in diameter do not contain physically bound water; this ability is possessed only by particles having a diameter less than the specified one. In particles with a diameter of 2 to 0.01 mm, the ability to retain physically bound water is weakly expressed. It increases with the transition to particles smaller than 0.01 mm and is most pronounced in red colloidal and especially colloidal particles. The ability to retain physically bound water depends on more than just particle size. A certain influence is exerted by the shape of the particles and their chemical and mineralogical composition. Humus and peat have an increased ability to retain physically bound water. The particle holds the subsequent layers of water molecules with less and less force. It is loosely bound water. As the particle moves away from the surface, the attraction of water molecules by it gradually weakens. The water goes into a free state.

The first layers of water molecules, i.e. hygroscopic water, soil particles attract with tremendous force, measured in thousands of atmospheres. Being under such a high pressure, the molecules of tightly bound water are very close together, which changes many of the properties of water. It acquires the qualities of a solid body, as it were. The soil retains loosely bound water with less force, its properties are not so sharply different from free water. Nevertheless, the force of attraction is still so great that this water is not subject to the force of gravity of the earth and differs from free water in a number of physical properties.

Capillary duty cycle determines the absorption and retention of moisture brought by atmospheric precipitation in a suspended state. The penetration of moisture through the capillary pores into the depth of the soil is extremely slow. Soil permeability is mainly due to non-capillary off-duty ratio. The diameter of these pores is so large that moisture cannot be held in them in a suspended state and seeps into the soil without hindrance.

When moisture enters the soil surface, the soil is first saturated with water to the state of field moisture capacity, and then filtration through non-capillary wells occurs through the water-saturated layers. Through cracks, shrew passages and other large wells, water can penetrate deep into the soil, ahead of water saturation up to the field capacity.

The higher the non-capillary duty cycle, the higher the water permeability of the soil.

In soils, in addition to vertical filtration, there is horizontal intrasoil movement of moisture. Moisture entering the soil, encountering a layer with reduced water permeability on its way, moves inside the soil above this layer in accordance with the direction of its slope.

Interaction with the solid phase

Main article: Soil absorption complex

The soil can retain substances that have entered it through various mechanisms (mechanical filtration, adsorption of small particles, formation of insoluble compounds, biological absorption), the most important of which is ion exchange between the soil solution and the surface of the soil solid phase. The solid phase is predominantly negatively charged due to the spalling of the crystal lattice of minerals, isomorphic substitutions, the presence of carboxyl and a number of other functional groups in the composition of organic matter, therefore the cation-exchange capacity of the soil is most pronounced. However, the positive charges responsible for the anion exchange are also present in the soil.

The totality of soil components with ion-exchange capacity is called the soil absorption complex (SAC). The ions that make up the PPC are called exchange or absorbed ions. A characteristic of the CEC is the cation exchange capacity (CEC) - the total number of exchangeable cations of the same kind held by the soil in a standard state - as well as the amount of exchangeable cations that characterizes the natural state of the soil and does not always coincide with the CEC.

The ratios between the exchangeable cations of PPC do not coincide with the ratios between the same cations in the soil solution, that is, the ion exchange proceeds selectively. Preferably, cations with a higher charge are absorbed, and if they are equal, with a higher atomic mass, although the properties of the PPC components may somewhat violate this pattern. For example, montmorillonite absorbs more potassium than hydrogen protons, while kaolinite does the opposite.

Exchangeable cations are one of the direct sources of mineral nutrition for plants, the composition of the PPK is reflected in the formation of organomineral compounds, soil structure and its acidity.

Soil acidity

soil air.

Soil air consists of a mixture of various gases:

oxygen, which enters the soil from atmospheric air; its content may vary depending on the properties of the soil itself (its friability, for example), on the number of organisms that use oxygen for respiration and metabolic processes;
carbon dioxide, which is formed as a result of the respiration of soil organisms, that is, as a result of the oxidation of organic substances;
methane and its homologues (propane, butane), which are formed as a result of the decomposition of longer hydrocarbon chains;
hydrogen;
hydrogen sulfide;
nitrogen; more likely to form nitrogen in the form of more complex compounds (for example, urea)

And this is not all the gaseous substances that make up the soil air. Its chemical and quantitative composition depends on the organisms contained in the soil, the content of nutrients in it, the weathering conditions of the soil, etc.

Living organisms in the soil

Soil is a habitat for many organisms. Creatures that live in the soil are called pedobionts. The smallest of these are bacteria, algae, fungi, and single-celled organisms that live in soil water. Up to 10¹⁴ organisms can live in one m³. The soil air is inhabited by invertebrates such as mites, spiders, beetles, springtails and earthworms. They feed on plant remains, mycelium, and other organisms. Vertebrates also live in the soil, one of them is the mole. He is very well adapted to living in completely dark soil, so he is deaf and almost blind.

The heterogeneity of the soil leads to the fact that for organisms of different sizes it acts as a different environment.

Spatial organization

In nature, there are practically no situations where any single soil with properties that are unchanged in space extends for many kilometers. At the same time, differences in soils are due to differences in the factors of soil formation.

The regular spatial distribution of soils in small areas is called the soil cover structure (SCC). The initial unit of SPP is the elementary soil area (EPA) - a soil formation within which there are no soil-geographical boundaries. ESAs alternating in space and to some extent genetically related form soil combinations.

soil formation

Soil-forming factors :

Elements of the natural environment: soil-forming rocks, climate, living and dead organisms, age and terrain,
as well as anthropogenic activities that have a significant impact on soil formation.

Primary soil formation

In Russian soil science, the concept is given that any substrate system that ensures the growth and development of plants "from seed to seed" is soil. This idea is debatable, since it denies the Dokuchaev principle of historicity, which implies a certain maturity of soils and the division of the profile into genetic horizons, but is useful in understanding the general concept of soil development.

The rudimentary state of the soil profile before the appearance of the first signs of horizons can be defined by the term "initial soils". Accordingly, the “initial stage of soil formation” is distinguished - from the soil “according to Veski” until the time when a noticeable differentiation of the profile into horizons appears, and it will be possible to predict the classification status of the soil. The term "young soils" is proposed to assign the stage of "young soil formation" - from the appearance of the first signs of horizons to the time when the genetic (more precisely, morphological-analytical) appearance is sufficiently pronounced for diagnosis and classification from the general positions of soil science.

Genetic characteristics can be given even before the maturity of the profile, with an understandable share of prognostic risk, for example, “initial soddy soils”; "young propodzolic soils", "young carbonate soils". With this approach, nomenclature difficulties are resolved naturally, based on the general principles of soil-ecological forecasting in accordance with the Dokuchaev-Jenney formula (representation of soil as a function of soil formation factors: S = f(cl, o, r, p, t ...)).

Anthropogenic soil formation

In the scientific literature for lands after mining and other disturbances of the soil cover, the generalized name “technogenic landscapes” has been fixed, and the study of soil formation in these landscapes has taken shape in “reclamation soil science”. The term "technozems" was also proposed, essentially representing an attempt to combine the Dokuchaev tradition of "-zems" with man-made landscapes.

It is noted that it is more logical to apply the term "technozem" to those soils that are specially created in the process of mining technology by leveling the surface and pouring specially removed humus horizons or potentially fertile soils (loess). The use of this term for genetic soil science is hardly justified, since the final, climax product of soil formation will not be a new “-earth”, but a zonal soil, for example, soddy-podzolic or soddy-gley.

For technogenically disturbed soils, it was proposed to use the terms "initial soils" (from the "zero moment" to the appearance of horizons) and "young soils" (from the appearance to the formation of diagnostic features of mature soils), indicating the main feature of such soil formations - the time stages of their development. evolution from undifferentiated rocks to zonal soils.

Soil classification

There is no single generally accepted classification of soils. Along with the international one (FAO Soil Classification and WRB, which replaced it in 1998), many countries around the world have national soil classification systems, often based on fundamentally different approaches.

In Russia, by 2004, a special commission of the Soil Institute. V. V. Dokuchaeva, led by L. L. Shishov, prepared a new classification of soils, which is a development of the 1997 classification. However, Russian soil scientists continue to actively use the USSR soil classification of 1977.

Among the distinguishing features of the new classification, we can mention the refusal to use factor-environmental and regime parameters for diagnosis, which are difficult to diagnose and often determined by the researcher purely subjectively, focusing attention on the soil profile and its morphological features. A number of researchers see this as a departure from genetic soil science, which focuses on the origin of soils and the processes of soil formation. The 2004 classification introduces formal criteria for assigning soil to a particular taxon, and uses the concept of a diagnostic horizon, which is accepted in the international and American classifications. Unlike the WRB and the American Soil Taxonomy, in the Russian classification, horizons and characters are not equivalent, but are strictly ranked according to their taxonomic significance. Undoubtedly, an important innovation of the 2004 classification was the inclusion of anthropogenically transformed soils in it.

The American school of soil scientists uses the Soil Taxonomy classification, which is also widespread in other countries. Its characteristic feature is the deep elaboration of formal criteria for assigning soils to a particular taxon. Soil names constructed from Latin and Greek roots are used. The classification scheme traditionally includes soil series - groups of soils that differ only in granulometric composition and have an individual name - the description of which began when the US Soil Bureau mapped the territory at the beginning of the 20th century.

Soil classification - a system for dividing soils by origin and (or) properties.

Soil type is the main classification unit, characterized by the commonality of properties determined by the regimes and processes of soil formation, and by a single system of basic genetic horizons.
- A soil subtype is a classification unit within a type, characterized by qualitative differences in the system of genetic horizons and in the manifestation of overlapping processes that characterize the transition to another type.
  - Soil genus - a classification unit within a subtype, determined by the characteristics of the composition of the soil-absorbing complex, the nature of the salt profile, and the main forms of neoplasms.
    - Soil type - a classification unit within a genus, quantitatively differing in the degree of expression of soil-forming processes that determine the type, subtype and genus of soils.
      - Soil variety is a classification unit that takes into account the division of soils according to the granulometric composition of the entire soil profile.
        Soil category - a classification unit that groups soils according to the nature of soil-forming and underlying rocks.

Distribution patterns

Climate as a factor in the geographical distribution of soils

Climate, one of the most important factors in soil formation and geographic distribution of soils, is largely determined by cosmic causes (the amount of energy received by the earth's surface from the Sun). The manifestation of the most general laws of soil geography is associated with climate. It affects soil formation both directly, by determining the energy level and hydrothermal regime of soils, and indirectly, by influencing other factors of soil formation (vegetation, vital activity of organisms, soil-forming rocks, etc.).

The direct influence of climate on the geography of soils is manifested in different types of hydrothermal conditions of soil formation. The thermal and water regimes of soils affect the nature and intensity of all physical, chemical and biological processes occurring in the soil. They regulate the processes of physical weathering of rocks, the intensity of chemical reactions, the concentration of soil solution, the ratio of the solid and liquid phases, and the solubility of gases. Hydrothermal conditions affect the intensity of the biochemical activity of bacteria, the rate of decomposition of organic residues, the vital activity of organisms and other factors, therefore, in different regions of the country with unequal thermal conditions, the rate of weathering and soil formation, the thickness of the soil profile and weathering products are significantly different.

The climate determines the most general patterns of soil distribution - horizontal zonality and vertical zonality.

The climate is the result of the interaction of climate-forming processes occurring in the atmosphere and the active layer (oceans, cryosphere, land surface and biomass) - the so-called climate system, all components of which continuously interact with each other, exchanging matter and energy. Climate-forming processes can be divided into three complexes: processes of heat exchange, moisture exchange and atmospheric circulation.

The value of soils in nature

Soil as a habitat for living organisms

The soil has fertility - it is the most favorable substrate or habitat for the vast majority of living beings - microorganisms, animals and plants. It is also significant that in terms of their biomass, the soil (the land of the Earth) is almost 700 times greater than the ocean, although the share of land accounts for less than 1/3 of the earth's surface.

Geochemical features

The property of different soils to accumulate various chemical elements and compounds in different ways, some of which are necessary for living beings (biophilic elements and microelements, various physiologically active substances), while others are harmful or toxic (heavy metals, halogens, toxins, etc.) , manifests itself in all plants and animals living on them, including humans. In agronomy, veterinary science and medicine, such a relationship is known in the form of so-called endemic diseases, the causes of which were revealed only after the work of soil scientists.

The soil has a significant impact on the composition and properties of surface and groundwater and the entire hydrosphere of the Earth. Filtering through the soil layers, water extracts from them a special set of chemical elements, characteristic of the soils of the catchment areas. And since the main economic indicators of water (its technological and hygienic value) are determined by the content and ratio of these elements, the disturbance of the soil cover also manifests itself in a change in water quality.

Regulation of the composition of the atmosphere

Soil is the main regulator of the composition of the Earth's atmosphere. This is due to the activity of soil microorganisms, which produce a variety of gases on a huge scale -

Fertilize, apply pesticides, water and loosen, from morning until late at night in the beds, but the harvest is not happy? Do you spend money on zoned modern varieties and hybrids, and as a result, pathetic diseased plants on the site? Maybe it's all about the soil?

Horticulture and horticulture is aimed at obtaining good harvests. Suitable plant varieties, timely application of fertilizers and pesticides, watering - all this affects the final result.

But proper agricultural technology gives the desired result only when taking into account the characteristics of the soil in this area. Let's look at the types and types of soil, their pros and cons.

Soil types are classified according to the content in it:

minerals (main part);
organics and, first of all, humus, which determines its fertility;
microorganisms and other living beings involved in the processing of vegetation residues.

An important quality of the soil is the ability to pass air and moisture, as well as the ability to retain incoming water.

For a plant, such a property of the soil as thermal conductivity (it is also called heat capacity) is extremely important. It is expressed in the period of time during which the soil is able to heat up to a certain temperature and, accordingly, give off heat.

The mineral part of any soil is sedimentary rocks formed as a result of the weathering of rock formations. Water flows over millions of years divide these products into two types:

sand;
clay.

Another mineral-forming species is limestone.

As a result, 7 main types of soils can be distinguished for the flat part of Russia:

Soil characteristics

clayey

Heavy, hard to work with, takes a long time to dry and warms up slowly in the spring. Poorly pass water and moisture to the roots of plants. Beneficial microorganisms develop poorly in such soil, and the process of decomposition of plant residues practically does not occur.

loamy

One of the most common soil types. In terms of quality, they are second only to chernozems. Suitable for growing all horticultural and horticultural crops.

Loams are easy to process, have normal acidity. They heat up quickly, but do not immediately release the stored heat.

A good environment for the development of underground microflora. The processes of decomposition and decay, due to air access, are intense.

Sandy

Easy for any treatment, they pass water, air and liquid fertilizers well to the roots. But these same qualities also have negative consequences: the soil quickly dries up and cools down, fertilizers during rains and irrigations are washed out with water and go deep into the soil.

sandy loam

Possessing all the positive qualities of sandy soils, sandy loams better retain mineral fertilizers, organic matter and moisture.

Lime

The soil is not suitable for gardening. It has little humus, as well as iron and manganese. An alkaline environment requires acidification of lime soil.

Peat

Plots in swampy places need to be cultivated and, above all, to carry out land reclamation work. Acidic soils must be limed annually.

Chernozem

Chernozem is the standard of soil, it does not need to be cultivated. Competent agricultural technology is all that is needed to grow a rich crop.

For a more accurate classification of the soil, its main physical, chemical and organoleptic parameters are considered.

Soil type characteristics	clayey	loamy	sandy	sandy loam	calcareous	peaty	black soil
Structure	Large-blocky	lumpy, textured	fine-grained	Finely lumpy	stony inclusions	loose	Granular-lumpy
Density	high	average	low	average	high	low	average
Breathability	Very low	average	high	average	low	high	high
Hygroscopicity	low	average	low	average	high	high	high
Heat capacity (heating rate)	low	average	high	average	high	low	high
Acidity	subacid	Neutral to acidic	Low, close to neutral	subacid	alkaline	sour	Slightly alkaline to slightly acidic
% humus	Very low	Medium, closer to high	short	average	short	average	tall
Cultivation	The introduction of sand, ash, peat, lime, organic matter.	Maintain the structure by adding manure or humus.	Introduction of peat, humus, clay dust, planting green manure.	Regular application of organics, autumn sowing of green manure	Application of organic, potash and nitrogen fertilizers, ammonium sulfate, sow green manure	The introduction of sand, abundant liming, manure, compost.	In case of depletion, the introduction of organic matter, compost, sowing green manure.
Crops that can grow	trees and shrubs with a developed root system that goes deep into the soil: oak, apple, ash	Almost all zoned varieties grow.	Carrots, onions, strawberries, currants	Most crops grow when using the right agricultural technology and zoned varieties.	Sorrel, lettuce, radish, blackberry.	Currant, gooseberry, chokeberry, garden strawberry	Everything grows.

The main types of soils in Russia

More than a hundred years ago, V.V. Dokuchaev discovered that the formation of the main soil types on the Earth's surface follows the law of latitudinal zonality.

Soil type is its attributes that occur under similar conditions and have the same parameters and conditions of soil formation, which in turn depend on climate over geologically significant periods of time.

The following soil types are distinguished:

The tundra and brown soils of semi-deserts are completely unsuitable for agriculture. Podzolic taiga and chestnut soils of dry steppes are infertile.

For agricultural activity, medium-fertile soddy-podzolic soil, fertile gray forest soil and the most fertile chernozem soil are of primary importance. The content of humus, climatic conditions with the necessary heat and moisture make these soils attractive for working on them.

We are used to seeing beauty in the clouds, in the surrounding nature, and never in the soil. But it is she who creates those unique pictures that remain in memory for a long time. Love, learn and take care of the soil on your site! She will repay you and your children with wonderful harvests, the joy of creation and confidence in the future.

Determination of the mechanical composition of the soil:

The importance of soil in the life of mankind:

The warmth of the sun, clean air and water are the main criteria for life on Earth. Numerous climatic zones led to the division of the territory of all continents and water space into certain natural zones. Some of them, even separated by vast distances, are very similar, others are unique.

Natural areas of the world: what is it?

This definition should be understood as very large natural complexes (in other words, parts of the geographic belt of the Earth), which have similar, uniform climatic conditions. The main characteristic of natural zones is the flora and fauna that inhabits this territory. They are formed as a result of uneven distribution of moisture and heat on the planet.

Table "Natural zones of the world"

natural area	climate zone	Average temperature (winter/summer)
Antarctic and Arctic deserts	Antarctic, arctic	24-70°С /0-32°С
Tundra and forest tundra	Subarctic and Subantarctic	8-40°С/+8+16°С
	Moderate	8-48°C /+8+24°C
mixed forests	Moderate	16-8°С /+16+24°С
broadleaf forests	Moderate	8+8°С /+16+24°С
Steppes and forest-steppes	subtropical and temperate	16+8 °С /+16+24°С
temperate deserts and semi-deserts	Moderate	8-24 °С /+20+24 °С
hardwood forests	Subtropical	8+16 °С/ +20+24 °С
Tropical deserts and semi-deserts	Tropical	8+16 °С/ +20+32 °С
Savannahs and woodlands		20+24°C and above
Variable rainforests	subequatorial, tropical	20+24°C and above
Permanently wet forests	Equatorial	above +24°C

This characteristic of the natural zones of the world is only introductory, because you can talk about each of them for a very long time, all the information will not fit in the framework of one table.

Natural zones of the temperate climate zone

1. Taiga. Surpasses all other natural zones of the world in terms of the area occupied on land (27% of the territory of all forests on the planet). It is characterized by very low winter temperatures. Deciduous trees do not withstand them, so the taiga is dense coniferous forests (mainly pine, spruce, fir, larch). Very large areas of the taiga in Canada and Russia are occupied by permafrost.

2. Mixed forests. Characteristic to a greater extent for the Northern Hemisphere of the Earth. It is a kind of border between the taiga and the broad-leaved forest. They are more resistant to cold and long winters. Tree species: oak, maple, poplar, linden, as well as mountain ash, alder, birch, pine, spruce. As the table "Natural areas of the world" shows, the soils in the zone of mixed forests are gray, not very fertile, but still suitable for growing plants.

3. Broad-leaved forests. They are not adapted to harsh winters and are deciduous. They occupy most of Western Europe, the south of the Far East, the north of China and Japan. Suitable for them is a maritime or temperate continental climate with hot summers and fairly warm winters. As the table "Natural zones of the world" shows, the temperature in them does not fall below -8 ° C even in the cold season. The soil is fertile, rich in humus. The following types of trees are characteristic: ash, chestnut, oak, hornbeam, beech, maple, elm. The forests are very rich in mammals (ungulates, rodents, predators), birds, including commercial ones.

4. Temperate deserts and semi-deserts. Their main distinguishing feature is the almost complete absence of vegetation and sparse wildlife. There are a lot of natural areas of this nature, they are located mainly in the tropics. There are temperate deserts in Eurasia, and they are characterized by sharp temperature changes during the seasons. Animals are represented mainly by reptiles.

Arctic deserts and semi-deserts

They are huge areas of land covered with snow and ice. The map of natural zones of the world clearly shows that they are located on the territory of North America, Antarctica, Greenland and the northern tip of the Eurasian continent. In fact, these are lifeless places, and polar bears, walruses and seals, arctic foxes and lemmings, penguins (in Antarctica) live only along the coast. Where the land is free of ice, lichens and mosses can be seen.

Moist equatorial forests

Their second name is rainforests. They are located mainly in South America, as well as in Africa, Australia and the Greater Sunda Islands. The main condition for their formation is a constant and very high humidity (more than 2000 mm of precipitation per year) and a hot climate (20 ° C and above). They are very rich in vegetation, the forest consists of several tiers and is an impenetrable, dense jungle that has become home to more than 2/3 of all types of creatures that now live on our planet. These rainforests are superior to all other natural areas of the world. Trees remain evergreen, changing foliage gradually and partially. Surprisingly, the soils of moist forests contain little humus.

Natural zones of the equatorial and subtropical climatic zone

1. Variably humid forests, they differ from rainforests in that precipitation falls there only during the rainy season, and during the period of drought that follows it, the trees are forced to shed their leaves. The animal and plant world is also very diverse and rich in species.

2. Savannas and woodlands. They appear where moisture, as a rule, is no longer enough for the growth of variable-humid forests. Their development occurs in the depths of the mainland, where tropical and equatorial air masses dominate, and the rainy season lasts less than six months. They occupy a significant part of the territory of subequatorial Africa, the interior of South America, partly Hindustan and Australia. More detailed information about the location is reflected in the map of natural areas of the world (photo).

hardwood forests

This climate zone is considered the most suitable for human habitation. Hardwood and evergreen forests are located along sea and ocean coasts. Precipitation is not so abundant, but the leaves retain moisture due to a dense leathery shell (oaks, eucalyptus), which prevents them from falling off. In some trees and plants, they are modernized into thorns.

Steppes and forest-steppes

They are characterized by the almost complete absence of woody vegetation, this is due to the meager level of precipitation. But the soils are the most fertile (chernozems), and therefore are actively used by man for agriculture. Steppes occupy large areas in North America and Eurasia. The predominant number of inhabitants are reptiles, rodents and birds. Plants have adapted to the lack of moisture and most often manage to complete their life cycle in a short spring period, when the steppe is covered with a thick carpet of greenery.

Tundra and forest tundra

In this zone, the breath of the Arctic and Antarctic begins to be felt, the climate becomes more severe, and even coniferous trees cannot withstand it. Moisture is in excess, but there is no heat, which leads to swamping of very large areas. There are no trees at all in the tundra, the flora is mainly represented by mosses and lichens. It is believed that this is the most unstable and fragile ecosystem. Due to the active development of gas and oil fields, it is on the verge of an ecological disaster.

All natural areas of the world are very interesting, whether it is a desert that seems completely lifeless at first glance, boundless Arctic ice or thousand-year-old rain forests with boiling life inside.

Soil is a complex biological complex that includes mineral (mechanical) and organic parts, soil air, water, microflora and microfauna. From this complex and a combination of influencing factors, such as climatic conditions, planting dates, variety, timeliness and literacy of agricultural practices, the quality of growing horticultural crops in your backyard depends. Also no less important when laying a garden, lawn or vegetable garden is the type of soil. It is determined by the content of mineral and organic particles.

The type of soil prevailing in your area determines the choice of crops, their placement, and ultimately the yield. Depending on this, a specific complex is developed to maintain fertility through proper processing and the application of the necessary fertilizers.

The main types of soils that owners of household and summer cottages most often encounter include: clay, sandy, sandy loam, loamy, calcareous and swampy. A more precise classification is as follows:

By organic composition- chernozems, gray soils, brown and red soils.

Each soil has both positive and negative properties, which means it differs in recommendations for improvement and selection of crops. In their pure form, they are rare, mostly in combination, but with a predominance of certain characteristics. Let's consider each type in detail.

Sandy soil (sandstones)

Sandstones are light soil types. They are loose, loose, easily pass water. If you pick up a handful of such earth and try to form a lump, then it will crumble.

The advantage of such soils— they quickly warm up, are well aerated, are easily processed. But at the same time, they quickly cool, dry out, weakly retain minerals in the root zone - and this flaw. Nutrients are washed out by water into the deep layers of the soil, which leads to a decrease in the presence of beneficial microflora and suitability for growing crops.

Sandstones

To increase the fertility of sandstones, it is necessary to constantly take care of improving their sealing and binding properties. This can be achieved by introducing peat, compost, humus, clay or drill flour (up to two buckets per 1 m²), using green manure (with incorporation into the soil), and high-quality mulching.

A more non-standard method of improving these soils is the creation of an artificial fertile layer by claying. To do this, in place of the beds, it is necessary to arrange a clay castle (lay clay in a layer of 5 - 6 cm) and pour 30 - 35 cm of sandy or loamy soil on it.

At the initial stage of processing, it is allowed to grow the following crops: carrots, onions, melons, strawberries, currants, fruit trees. Cabbage, peas, potatoes and beets will feel somewhat worse on sandstones. But, if you fertilize them with fast-acting fertilizers, in small doses and often enough, you can achieve good results.

Sandy soil (sandy loam)

Sandy loam is another variant of soils that are light in texture. In terms of their qualities, they are similar to sandstone, but contain a slightly higher percentage of clay inclusions.

The main advantages of sandy loam- they have a better holding capacity for mineral and organic substances, they warm up quickly and hold it for a relatively long time, they pass moisture less and dry out more slowly, they are well aerated and can be easily processed.

sandy soil

With conventional methods and the choice of zoned varieties, anything can grow on sandy loamy soil. This is one of the good options for gardens and orchards. However, methods of increasing and maintaining fertility for these soils are also acceptable. This involves the introduction of organic matter (in normal doses), the sowing of green manure crops, and mulching.

Clay soil (alumina)

Alumina are heavy soils with a predominance of clayey and loess (silty) sedimentary rocks. They are difficult to cultivate, have little air and are colder than sandy soils. The development of plants on them is somewhat delayed. Water can stagnate on the surface of very heavy soils due to the low water absorption coefficient. Therefore, growing crops on it is quite problematic. However, if clay soil is properly cultivated, it can become quite fertile.

How to identify clay soil? After digging, it has a large-lumpy dense structure, when wet, it sticks to the feet, does not absorb water well, and easily sticks together. If a handful of wet alumina is rolled into a long "sausage", then it can be easily bent into a ring, while it will not crumble into pieces or crack.

Clay type of soil

To facilitate the processing and beneficiation of alumina, it is recommended to periodically add substances such as coarse sand, peat, ash and lime. And you can improve the biological quality with the help of manure and compost.

The introduction of sand into clay soil (no more than 40 kg per 1 m 2) makes it possible to reduce the moisture capacity and thus increase its thermal conductivity. After sanding, it becomes suitable for processing. In addition, its ability to warm up and water permeability increases. Ash enriches with nutrients. Peat loosens and increases water-absorbing properties. Lime reduces acidity and improves soil air conditions.

Recommended Trees for Clay Soils: hornbeam, pear, pedunculate oak, willow, maple, alder, poplar. shrubs: barberry, periwinkle, hawthorn, weigela, derain, viburnum, cotoneaster, hazel, magonia, currant, snowberry, spirea, chaenomeles or Japanese quince, mock orange or garden jasmine. From vegetables potatoes, beets, peas and Jerusalem artichoke feel good on clay.

Particular attention on clay soils must be paid to loosening and mulching.

Loamy soil (loams)

Loamy soil is the most suitable type for growing horticultural crops. It is easy to process, contains a large percentage of nutrients, has high air and water permeability, is able not only to retain moisture, but also to evenly distribute it over the thickness of the horizon, and retains heat well.

You can determine the loam by taking a handful of this soil in the palm of your hand and roll it up. As a result, you can easily form a sausage, but when deformed, it collapses.

Due to the combination of available properties, loamy soil does not need to be improved, but it is only necessary to maintain its fertility: mulch, periodically apply organic and mineral fertilizers.

All types of crops can be grown on loams.

calcareous soil

Lime soil belongs to the category of poor soils. Usually it has a light brown color, a large number of stony inclusions, does not give iron and manganese to plants well, and can have a heavy or light composition. At elevated temperatures, it quickly heats up and dries out. In crops grown on such soil, foliage turns yellow and unsatisfactory growth is observed.

calcareous soil

To improve the structure and increase the fertility of calcareous soils, it is necessary to regularly apply organic fertilizers, mulch, sow green manure, and apply potash fertilizers.

Everything is possible to grow on this type of soil, but with frequent loosening of row spacing, timely watering and thoughtful use of mineral and organic fertilizers. Will suffer from weak acidity: potatoes, tomatoes, sorrel, carrots, pumpkin, radish, cucumbers and salads. Therefore, they need to be fed with fertilizers that tend to acidify (ammonium sulfate, urea), and not alkalize the soil, for example.

Marshy soil (peat)

Marshy (peaty) soils are not uncommon in garden plots. Unfortunately, it is difficult to call them good for growing crops. This is due to the minimum content of plant nutrients in them. Such soils quickly absorb water, just as quickly give it away, do not warm up well, often have a high acidity index.

The only advantage of marshy soils is that they retain mineral fertilizers well and are easy to cultivate.

swampy soil

To improve the fertility of swampy soils, it is necessary to enrich the earth with sand or clay flour. You can also apply liming and fertilizer.

To lay a garden on peat soils, it is better to plant trees either in pits, with soil individually laid for cultivation, or in bulk hills, from 0.5 to 1 meter high.

Using as a garden, the peat bog must be carefully cultivated or, as in the variant with sandy soils, a clay layer should be laid and loam mixed with peat, organic fertilizers and lime should be poured on it. For the cultivation of gooseberries, currants, chokeberries and garden strawberries, you can do nothing, just water and weed, since these crops grow on such soils even without cultivation.

Chernozems

Chernozems are soils of high potential fertility. A stable granular-cloddy structure, a high humus content, a high percentage of calcium, good water-absorbing and water-retaining abilities allow us to recommend them as the best option for growing crops. However, like any other soil, they tend to deplete from constant use. Therefore, already 2-3 years after their development, it is recommended to apply organic fertilizers to the beds and sow green manure.

Chernozem

Chernozems can hardly be called light soils, so they are often loosened by adding sand or peat. They can also be acidic, neutral and alkaline, which also needs to be controlled. To determine the black soil, it is necessary to take the guest of the earth and squeeze it in the palm of your hand. The result should be a black bold print.

Serozems

For the formation of serozems, loess-like loams and loess with pebble bedding are necessary. Plain gray soils are formed on clayey and heavy loamy deluvial and alluvial rocks.

The vegetation cover of zones with gray soils is characterized by pronounced zonality. At the lower level, as a rule, there is a semi-desert with bluegrass and sedge. It gradually passes into the next zone with a semi-desert and bluegrass, sedge, poppy and barley representing it. Higher areas of the foothills and low mountains are mainly occupied by wheatgrass, barley and other crops. Willows and poplars grow on river floodplains.

Serozem

The following horizons are distinguished in the profile of serozems:

Humus (thickness from 12 to 17 cm).
Transitional (thickness from 15 to 26 cm).
Carbonate illuvial (60 to 100 cm thick).
Silty-loamy with inclusions at a depth of more than 1.5 m of fine-grained gypsum.

Serozems are characterized by a relatively low content of humic substances - from 1 to 4%. In addition, they are distinguished by an increased level of carbonates. These are alkaline soils with insignificant indicators of absorptive capacity. They contain a certain amount of gypsum and easily soluble salts. One of the properties of gray soils is the biological accumulation of potassium and phosphorus. Soils of this type contain quite a lot of easily hydrolysable nitrogen compounds.

In agriculture, gray soils can be used subject to special irrigation measures. Most often they grow cotton. In addition, beets, rice, wheat, corn and melons can be successfully cultivated in areas with gray soils.

To improve the quality of gray soils, in addition to irrigation, measures are recommended to prevent secondary salinization. It will also require regular application of organic and mineral fertilizers, the formation of a deep arable layer, the use of the alfalfa-cotton crop rotation method and the sowing of green manure.

Brown soils

Brown forest soils are formed on variegated and red-colored gravel-loamy, proluvial, alluvial and alluvial-deluvial rocks of the plains, located in the foothills under deciduous, beech-hornbeam, oak-ash, beech-oak and oak forests. In the eastern part of Russia, they are localized on foothill and intermountain plains and are located on clayey, loamy, alluvial and eluvial-deluvial bases. They often grow mixed, spruce, cedar, fir, maple and oak forests.

Brown soils

The process of formation of brown forest soils is accompanied by the release of soil-forming and weathering products from the thickness of the soil profile. They usually have a mineral, organic and organo-mineral structure. For the formation of soil of this type, the so-called litter (fallen parts of plants), which is a source of ash components, is of particular importance.

The following horizons can be identified:

Forest litter (0.5 to 5 cm thick).
Rough humus humus.
Humus (up to 20 cm thick).
Transitional (thickness from 25 to 50 cm).
Maternal.

The main characteristics and composition of brown forest soils vary significantly from one horizon to another. In general, these are soils saturated with humus, the content of which reaches 16%. A significant part of its components is occupied by fulvic acids. Soils of the presented type are acidic or slightly acidic. They often undergo processes of claying. Sometimes the upper horizons are depleted in silty components.

In agriculture, brown forest soils are traditionally used for growing vegetables, cereals, fruit and industrial crops.

To determine what type of soil prevails on your site, it is best to contact specialists. You will be helped to find out not only the type of soil by the content of minerals, but also the presence of phosphorus, potassium, magnesium and other useful microelements in it.