What is black soil? Chernozem soils What is the mechanical composition of the soil chernozem

Chernozem is the most fertile of all other known soil types. As a rule, Russian chernozem is formed in the steppe and forest-steppe regions of Russia, and its formation itself takes more than a dozen years. For the formation of chernozem, certain natural conditions are necessary, for example, such as a moderately cold and dry climate, an abundance of meadow and steppe vegetation. In the process of decomposition (humification) of a huge amount of plant residues that accumulate annually in the soil, the so-called humus is formed and accumulated in the upper layer of the soil, which, in fact, is humus. Humus is considered the most valuable element in the composition of chernozem. It is due to the high humus content that chernozem has the highest fertility rates among all other types of soils, and a characteristic black or dark brown color with a "greasy" shade. In addition to humus, black soil is rich in many other useful and essential microelements for vegetation, for example, nitrogen, potassium, phosphorus and others.

Chernozem properties

Due to the loamy and granular-lumpy structure of the chernozem soil, which is ideal for the growth and development of vegetation, the most optimal water-air balance is stably maintained in the chernozem soil. The acidity of chernozem is neutral, and the content of various soil microorganisms and calcium in it is simply enormous. The quantitative content of humus in chernozem soil can be up to 15%. All of the above properties in aggregate determine such high fertile properties of chernozem. Depending on the quantitative content of humus and the conditions in which the formation took place, chernozem is classified as: leached, podzolized, ordinary, typical and southern.

Application of chernozem

Chernozem is ideal for almost all types of plantations and, in most cases, does not require additional mixing with other components, for example, with organic and mineral fertilizers. In climates with good humidity, chernozem can be extremely fertile. Chernozem soil is used with great success in the cultivation of crops such as cereals, vegetables, fodder, as well as in the cultivation of orchards and vineyards, in greening works in large cities and megalopolises, in landscape design. Usually, the extraction and delivery of chernozem is carried out in order to form a rich fertile soil layer. It is known that the addition of black soil even to the most impoverished and depleted soil gives an excellent health-improving effect, in which almost all soil characteristics are restored, and above all, water permeability and nutrient content. The greatest effect is achieved when using black soil on light sandy and sandy loam soils. The use of chernozem is possible both separately and together with other soil mixtures. However, it should be noted that a single use of chernozem to enrich and improve a particular soil will not solve the problem of fertility once and for all. Unfortunately, after a few years, the microbiological composition of the soil will again be depleted and impoverished, which, accordingly, will lead to a decrease in the amount of nutrients.

Chernozem pH 6.0 -7.0

As already noted, chernozem is characterized by the highest, in comparison with other types of soils, natural fertility and humus content, as well as the presence of a granular-lumpy soil structure and loamy texture that is optimal for the growth and development of vegetation. It is also important that the chernozem soil contains a huge number of soil microorganisms. In Russia, chernozem soil is most common in the southern regions (Lipetsk, Tula, Ryazan, Voronezh, Belgorod and Kursk regions). As for the Moscow region, there are practically no black earth lands. When buying black soil to improve fertility on a personal plot, do not forget that a one-time introduction of black soil into depleted soil will not solve the problem with fertility forever, since a change in natural conditions for black soil will lead to a change in its microbiological composition, a decrease in the content of nutrients and the destruction of soil aggregates. As a result, after a few years, chernozem will turn into an ordinary clay substrate, cracking when it dries and turning into ordinary mud after rain. Chernozem is quite simple to use, but its use in the conditions of Moscow and the Moscow region should be carried out with the addition of sand or peat, for greater looseness of the soil layer of the earth.

Note

The use of chernozem on heavy loamy and clayey soils is ineffective. The greatest effect can be achieved by using black soil on light sandy soil.

If the trial digging and tree planting test pits show that the soil is not suitable for tree planting, soil improvement and preparation of soil for filling the planting pits should be carried out. Chernozem and humus soils often need the addition of clay and lime: clay will make the soil more cohesive, will help to better retain absorbed moisture, while lime helps plants to better absorb nutrients. In addition, lime helps to improve the structure of the soil by binding its finest particles.

From the school course, many remember well that the highest fertility rate is in the black soil, for which Russia was once famous. However, when trying to give a precise and detailed definition of the concept, difficulties may arise.

At the same time, summer residents simply need to have an idea of ​​what black soil is and what is its main difference from other types of soils and types of soil.

Chernozems are formed in certain soil and climatic conditions and are a living ecosystem. But today there are many companies specializing in the supply of soil to any region of Russia, which expands the possibilities of summer residents and owners of private houses to improve the soil on their land plot.

Characteristics and properties of chernozem

Chernozem is a special type of soil that forms on loesslike loams or loesses under the influence of a temperate continental climate with periodic changes in positive and negative temperatures and moisture levels with the participation of living microorganisms and invertebrates. As can be seen from the definition, chernozem cannot be produced in artificial conditions or obtained by applying various types of fertilizers.

The main characteristic of the soil is the percentage of humus. Chernozem has a record high humus content (organic matter formed in the course of complex biochemical reactions and is the most accessible form for plant nutrition). In the chernozems of our ancestors, its level was 15% or more, but today it is considered to be a maximum of 14%. The fact is that during intensive farming, humus does not have time to recover and the soil is depleted.

Do not assume that black soil is just fertile soil. In fact, its concept is much broader. It cannot be compared with organic fertilizers such as manure or humus, since the concentration of nutrients in them is so high that excessive application of them can adversely affect plant growth. In black soil, all substances are balanced and are in an easily accessible form.

The next distinguishing feature of chernozem is its high calcium content, the need for which in cultivated plants is the highest at all stages of growth.

Chernozem is characterized by a neutral or close to neutral reaction of the soil solution, which makes it universal for growing crops.

Chernozem has a granular-lumpy structure, which is resistant to leaching, crusting, weathering and compaction. Thanks to this structure, optimal water-air exchange with the atmosphere is ensured and favorable conditions for root growth are created. However, according to experts, chernozem is not loose enough and requires the addition of sand or peat.

Subtypes of chernozem

In different climatic zones (Central Chernozem, Volga, Northern Caucasus and Western Siberia), chernozem is formed with some peculiarities. In total, 5 subtypes are distinguished: podzolized (deciduous forests), leached (forest-steppe zone), typical (meadows and forest-steppe), ordinary (steppes) and southern (steppes of the southern regions). The southern chernozem has the highest humus content.

How to recognize black soil?

Chernozem differs significantly from humus and manure. Manure is a waste product of livestock and poultry farming and is a partially digested plant fiber with a high organic content. Manure that has rotted over several years under the influence of microorganisms and invertebrates (worms and insects) turns into humus, containing nutrients in a form more accessible to plants. Both manure and humus contain a very large amount of nitrogen and its compounds.

Peat is very close to chernozem in origin, which is also formed as a result of long-term decomposition of plant residues, but in other climatic conditions.

You can give some tips on how to distinguish black soil from other soils:

• has a rich black color;
• due to the high humus content, leaves a greasy mark on the palm after compression;
• when wet, it resembles clay in consistency and does not dry out for a long time, retaining moisture (unlike peat);
• has a coarse-grained structure.

It is rather difficult to acquire real chernozem with a quality certificate in the Moscow region, since its extraction is limited and there is a high probability of buying just dark soil. At best, you will be lucky to get a mixture of black soil with low-lying peat, which, with the right proportion, can even be a plus.

The use of black soil at their summer cottage

The desire of summer residents to increase the fertility of the soil on their site to obtain high yields of high quality fruits explains their willingness to use all available means. To achieve a high effect and keep it for several years, you need to know how to use black soil in the garden without harming the already established ecosystem.

The main delusion of gardeners is that by completely replacing the soil with chernozem, it is possible to solve the problem of plant nutrition for all time without the subsequent introduction of fertilizers and the use of humus or compost. The nutrients in black soil are actively used by plants for the formation of crops and seeds, therefore, without their replenishment, the humus content drops sharply and the soil is depleted.

Excessive introduction of chernozem for vegetable and flower crops will be a gross mistake, since their thin root system is not able to maintain the required porosity, which will eventually lead to soil compaction. It is recommended to add black soil mixed with garden soil and peat. A good result is obtained by its introduction into greenhouses, hotbeds and flower beds for perennial ornamental plants. For these purposes, it is very convenient to use black soil in bags.

Areas where chernozem was introduced should be dug up only with a pitchfork to prevent soil compaction. Earthworms are a good biological indicator of soil conditions.

Before applying, it is advisable to check the acidity level of chernozem using indicator strips. With a weakly acidic reaction, you will need to add lime, dolomite flour or wood ash, and with a slightly alkaline reaction, acidic mineral fertilizers.

How much does black soil cost?

In organizations specializing in the sale of fertile soil, you can buy black soil with delivery to any settlement in the Moscow region.

At the same time, the average price of 1 m3 of chernozem with delivery is 1300 rubles. when ordering a car for 20 m3. When ordering a dump truck for 10 m3, the price increases to about 1650 rubles. To calculate how much a car of chernozem costs, let's take a volume of 10 m3 as the initial data. The result is a quite acceptable amount of 16,500 rubles. The larger the volume, the lower the price for 1 m3.

However, for summer cottages, there may not be a need for such volumes. In such cases, you can purchase prepackaged black soil in bags of 40 or 50 liters. The cost of one bag ranges from 180 to 300 rubles. Bulk discounts apply for more than 50 bags from most suppliers.

When planning delivery and unloading operations, the weight of chernozem must be taken into account. Depending on the structure and composition, 1 m3 of chernozem weighs from 1 to 1.3 tons.

Chernozems develop in the steppe zone. Chernozems can and do occur on any rocks (on granites in the Ukraine, on basalts in the Transcaucasus), but loesslike rocks contribute most of all to the formation of chernozems.

The nature of the parent rock affects the soil and, along with the topography, for example, gives rise to various soil varieties. However, the direction of soil formation remains the same - evidence that soil formation in this case is regulated by some more general cause. This common cause is the climate and the nature of the vegetation.

The climate in the steppes is dry. This is caused both by the small (400-500 mm) amount of atmospheric precipitation, and by the fact that they fall mainly in summer, when temperatures are high and, therefore, evaporation is high. A number of conclusions can be drawn from this fact:

1. Since there is little moisture, the soil should be slightly washed out. This should lead to a weak dismemberment of the soil profile into horizons, to the richness of the soil with bases (which are almost never removed from it) and to the fact that only readily soluble substances will be carried out from the upper horizons to the lower ones.

2. In the steppes, only herbaceous vegetation develops, but since it dies off annually, a very large amount of organic matter enters the soil annually, both in the form of remnants of terrestrial parts of plants, and in the form of remnants of their dense root system.

3. Mineralization of organic matter should be weak. In summer, the soil dries up, in winter, if the snow cover is not thick enough, it freezes. Consequently, for the winter, biochemical processes are sharply slowed down or stopped. High summer temperatures favor the activity of microorganisms that decompose organic matter, but the lack of moisture inhibits their activity. As a result, organic residues cannot be completely decomposed, incomplete decomposition products accumulate and, therefore, the soil must be rich in humus.

4. The parent rock (loess) contains a lot of salts, especially calcium carbonates. Therefore, the soil solution is rich in electrolytes, and the absorbing complex is saturated with calcium. Under these conditions, colloids should be in a collapsed state. The consequences of this fact are twofold: soil particles are bound into aggregates, forming a solid granular (with a grain diameter not exceeding a few millimeters), which is very favorable for the water and air regime of the soil; The formation of the structure is also assisted by a dense network of roots, which dismember the soil into small lumps. In addition, folded organic colloids saturated with calcium are known to be difficult to destruct (disperse) even in the presence of a large amount of water, i.e., they become hardly mobile, and thus humic substances are protected from the destructive action of water and from removal from the soil, accumulate. In other words, the accumulation of humus in chernozems should be facilitated not only by the slow biochemical decomposition of organic substances, which occurs only in spring, when there is enough moisture in the soil, but also by the properties of the rock itself, which contains many electrolytes, including such an energetic coagulator as calcium ion.

All the features described above are indeed inherent in typical black soil. Two main horizons can be distinguished in it: humus and carbonate. The humus horizon is dark, almost black, as it contains 4-18% humus; it is eluvial-accumulative (because humus accumulates in it, and simple salts and solutions of some organic substances are carried out) and is divided into subhorizons A and B 1. An indicator of the weakness of the eluvial process is that the composition of the soil along the horizons changes relatively little, only in the lower horizons a noticeable accumulation of carbonates is found.

The thickness of the black subhorizon A, which has a well-defined granular structure, is 50 centimeters or more. Horizon B 1 (50-70 cm thick) is almost the same color, but under the influence of HCl solution it boils in its lower part, indicating that carbonates are not completely washed out of it. The gray-fawn B 2 horizon (40-60 cm thick) boils very violently, and the release of calcium carbonates in the form of white specks is very abundant here. All the horizons described contain humic substances, and a change in their color is an indicator of a decrease in the humus content from top to bottom. Loess is the parent material for typical black soil.

Due to the heterogeneity of the natural conditions of the steppe zone, there are many varieties of chernozems. The drier the climate, the less humus in the chernozems; in addition, the thickness of horizon A, the degree of soil overburden, etc. change. 10%) and southern (4-6%). These subtypes, in turn; according to the thickness of the humus horizon, each is subdivided into powerful (more than 80 cm), medium-thick (50-80 cm) and low-power (less than 50 cm).

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VV Dokuchaev called chernozems "the king of soils" in connection with their high fertility. There are various hypotheses and theories about the origin of chernozems. Some researchers were inclined to the marine origin of chernozems, that is, they considered them as sea silt left after the retreat of the Caspian and Black Seas. Other scientists considered black soil a product of redeposition by the glacial sea and icebergs of black Jurassic shale clay. Then, a theory of the swamp origin of chernozem was put forward, according to which the chernozem zone in the past was a very swampy tundra. During the drainage of the territory with the onset of a warm climate, the decomposition of bog and tundra vegetation, bog silt and the settlement of terrestrial vegetation took place, as a result of which chernozems were formed.

More accurate ideas about the origin of chernozem belong to MV Lomonosov, who in his work "On the layers of the earth" (1763) wrote that chernozem is not primordial and not primordial matter, but came from the cognition of animals and plant bodies over time.

The theory of the plant-terrestrial origin of chernozems was expressed by F. Ruprecht in his work "Geobotanical Research on Chernozem" (1866). He considered the emergence of chernozems as a result of the settlement of herbaceous plants and the accumulation of humus during their decomposition, without attaching importance to other soil-forming factors.

PA Kostychev in his work "Soils of the Chernozem Region of Russia" (1886) assigned a special role to the root systems of herbaceous plants in the accumulation of humus.

VR Williams believed that the genesis of chernozems was the result of the development of the sod process under the meadow steppes.

The origin of chernozems on a scientific basis was proved by VV Dokuchaev in his work "Russian Chernozem" (1883). He considered the formation of black earth to be the result of the accumulation of humus in the rock "from the decay of herbaceous steppe, not forest vegetation, under the influence of climate, age of the country, vegetation, terrain and parent rocks." He associated the type of vegetation, the rate of its development, the nature and rate of decomposition of plant residues with the climate.

Subsequently, Chernozems were studied by many researchers (N.M. Sibirtsev, I.V. Tyurin, P.G. Aderikhin, E.A.Afanasyeva, E.A. that chernozems are soils formed under perennial herbaceous vegetation of the forest-steppe and steppe under conditions of a non-flush or periodically flushed water regime. The leading process of soil formation is an intensive sod process, as a result of which a powerful humus-accumulative horizon A develops, nutrients accumulate and the soil is structured.

The herbaceous community consists mainly of grasses and forbs with a powerful reticulate-fibrous root system.

Annual litter is 20 ... 30 t / ha, while most of it (65 ... 75%) falls on the root mass, which is rich in protein nitrogen, bases (calcium, magnesium). Litter is decomposed mainly by spore-forming bacteria and actinomycetes with sufficient oxygen supply, optimal moisture, without intensive leaching in a neutral environment. 600 ... 1400 kg / ha of nitrogen and ash elements are supplied annually with waste. The ash content of litter is 7 ... 8%.

In the spring, with a sufficient amount of moisture, organic matter quickly decomposes, and plant nutrients are released. In summer, the moisture reserve is reduced to wilting moisture. Under such conditions, the mineralization of organic residues is suspended, as a result of which humus is formed and accumulates. Due to the shallow filtration of atmospheric precipitation waters, nutrients are accumulated in the upper horizons. The fixation of humus is promoted by calcium. Winter cooling and freezing of soils also contribute to the accumulation of humus, since humus denaturation occurs at low temperatures. In summer, during the period of desiccation and in winter during freezing, humic substances are fixed and become more complex. Their composition is dominated by humic acids and calcium humates, leading to the formation of a water-resistant granular structure. This is also facilitated by carbonate soil-forming rocks, high ash content of plant residues, and ash saturation with bases. The most favorable conditions for the formation of chernozem are typical for the southern part of the forest-steppe. In the steppes, there is a moisture deficit, the amount of incoming litter decreases, therefore, the intensity of humus formation decreases.

The classification of chernozems was first given by V.V.Dokuchaev, who singled them out as an independent type and subdivided them into watersheds, slopes and terraces. Much attention was paid to the classification of chernozems by N. M. Sibirtsev, S. I. Korzhinsky, L. I. Prasolov, P. G. Aderikhin and others. At present, chernozems are combined into facies: warm South European, moderate East European, cold West and East Siberian, deep freezing East Siberian. The facies of the zone are subdivided into subzones-subtypes: in the forest-steppe - podzolized, leached, typical, and in the steppe - ordinary and southern chernozems. Optimal conditions for the formation of chernozems are in the southern part of the forest-steppe (typical chernozems), where the largest amount of plant mass is concentrated and a favorable hydrothermal regime has been established.

Chernozems are subdivided into types according to the thickness of the humus horizon, according to the humus content and according to the severity of the accompanying process. According to the thickness of the humus horizon (A + AB), chernozems are divided into super-powerful (more than 120 cm), powerful (80 ... 120 cm), medium-thick (40 ... 80 cm), low-power (25 ... 40 cm), very low-power (less than 25 cm). According to the humus content, fat (more than 9%), medium humus (6% ... 9%), low humus (4% ... 6%), low humus (less than 4%) chernozems are distinguished. According to the severity of the accompanying process, chernozem soils can be weakly, medium-strongly solonetzic; weak, medium, highly leached, etc.

The profile of chernozems in generalized form has the following morphological structure: A d - steppe felt up to 5 cm thick, consists of roots and intertwined stems of grasses on virgin soil, absent in arable soils; A - humus-accumulative horizon with a thickness of 40 ... 130 cm and more, dark gray or black, granular or granular-lumpy, with beads on the roots of plants; AB - transitional dark gray humus horizon, granular-lumpy in structure, with noticeable browning downward of the horizon or with dark brown spots; B - horizon of humus streaks 40 ... 80 cm thick, brownish-gray, lumpy, often subdivided by structure and degree of humus into subhorizons B 1, B 2, B 3; these horizons contain calcium carbonates in the form of pseudomycelium, cranes, white-eyed (except for highly leached and podzolized chernozems); ВС К - illuvial-carbonate horizon, transitional to the parent rock, brownish-fawn, lumpy-prismatic; C - pale soil-forming rock with carbonate excretions, and in southern chernozems and with gypsum. Moleholes are found along the entire profile; the transitions between the horizons are gradual.

Podzolized chernozems (Fig., A) are developed under broad-leaved herbaceous forests on loess-like and mantle loams, loesses. The thickness of the humus horizon (A + AB) varies from 30 ... 50 cm (cold Western and Central Siberian facies) to 70 ... 100 cm (warm South European facies). Horizon A is predominantly dark gray, granular, and lumpy when plowed. A grayish tint is observed in the AB horizon (a whitish coating of silica powder SiO 2 on structural units). Horizon B has a nutty or nutty-prismatic structure; on the edges of structural units, brown films, humus smears, and silica powder are noted; more dense, with a gradual transition to the parent rock C. Soils boil from a depth of 130 ... 150 cm. The BC horizon contains carbonates in the form of calcareous tubes, cranes, dutik.

Slightly podzolized chernozems have a silica powder in the lower part of the AB horizon and in the B horizon, and medium-podzolized chernozems - throughout the humus layer and in the B 1, B 2 horizons.

Podzolized chernozems are subdivided into main genera: ordinary, merged, poorly differentiated, carbonate-free.

The reaction of the upper horizons is weakly acidic or close to neutral (pH 5.5 ... 6.5). The absorption capacity is 30 ... 50 mg eq / 100 g of soil; the soil absorbing complex is saturated with bases, and the AB horizon contains exchangeable hydrogen (up to 3%). Horizon A contains 5 ... 12% humate humus. In horizon B, an increase in silt content is observed.

Leached chernozems (Fig., B) are formed under forb-cereal vegetation. Their profile has a well-defined dark gray humus horizon A. It is loose or weakly compacted, has a lumpy-granular structure. This horizon lacks a whitish siliceous powder. Horizon AB with a thickness of 30 ... 50 cm in the East Siberian facies to 80 ... 150 cm in a warm facies, dark gray with a brownish tint. Under it lies a compacted brownish carbonate-free horizon B 20 ... 50 cm thick, with humus streaks, smears and films along the edges of a lumpy-nutty or lumpy-prismatic structure; the transition is gradual. Horizon ВС К - illuvial-carbonate, fawn, compacted, nutty-prismatic, with efflorescence, streaks, mycelium, mealy accumulations, carbonate cranes. C k - pale-pale calcareous parent rock. There are no gypsum or readily soluble salts.

The following types of leached chernozems are distinguished: weakly leached (the boiling line runs no more than 20 cm from the lower boundary AB), moderately leached (at a depth of 20 ... 50 cm from the border of the humus layer), highly leached (below 50 cm from the boundary AB) ... A feature of these soils is the absence of free carbonates in the A and AB horizons.

Typical chernozems (Fig., C) are formed under forb-cereal vegetation on loesses, loess-like and mantle loams. They are characterized by a large thickness of the humus layer - from 50 ... 70 cm (cold facies) to 100 ... 190 cm (warm facies), the presence of carbonates in the form of mycelium, calcareous tubules in the AB horizon. More often carbonates are observed from a depth of 60 ... 70 cm. Horizon A, up to 130 cm thick, is black or grayish-black, granular, and AB is dark gray with a barely noticeable brownish tint, often with darker streaks. Below AB lies a grayish-brown compacted illuvial-carbonate horizon B k with tongues and streaks of humus, lumpy-prismatic structure, with carbonates mainly in the form of mycelium, efflorescence, and cranes. This horizon gradually turns into the BC K horizon - pale brown, transitional to the rock, with a significant amount of carbonate veins and cranes. C k - calcareous, fawn-colored soil-forming rock. Gypsum and readily soluble salts are absent in the entire soil profile. There are many mole holes in the soils.

Ordinary chernozems (Fig., D) are distributed under the steppe forb-fescue-feather grass vegetation. These soils are less powerful than typical chernozems. Their humus horizon ranges from 35 ... 45 cm (cold East Siberian facies) to 80 ... 140 cm (warm facies). The soils have a brownish tint against the general dark gray background and a lumpy structure of the AB horizon. Horizon B (humus infiltrates) often coincides with the carbonate horizon or B k, or BC K. The structure of this horizon is prismatic, the color is brownish-fawn. Carbonates are represented by spots of white-eyed and pseudomycelium, powdery impregnation. Sometimes readily soluble salts and gypsum are released at a depth of 200 ... 300 cm. C k - pale-pale calcareous parent rock. There are many mole holes in the soil profile.

Rice. The structure of the profile of chernozems: a - podzolized; b - leached; c - typical; g - ordinary; d - southern

Southern chernozems (Fig., E) formed under fescue-feather grass steppe vegetation. They have a small humus layer (from 25 ... 30 to 70 ... 80 cm). Horizon A 20 ... 30 cm thick, dark gray with a brown tint, lumpy and granular lumpy structure. Horizon AB (30 ... 40 cm) brownish-dark gray, nutty-lumpy, compacted. Below lies the carbonate horizon В к, brown with humus streaks, compacted, nutty-prismatic, containing mycelium, efflorescence, powdery precipitates of carbonates. VS K is a brownish-fawn illuvial-carbonate horizon, compacted, prismatic, with a large amount of white-eyed. C - pale yellow carbonate rock, gypsum precipitates are found from a depth of 150 ... 200 cm, and readily soluble salts from a depth of 200 ... 300 cm. Moles are observed in the soil profile.

Ciscaucasian chernozems form a peculiar group. From the surface they have a dark gray color with a brownish tint, a powerful humus horizon (120 ... 150 cm and more). These soils boil already in horizon A.

Meadow-chernozemic soils develop under conditions of increased moisture on poorly drained plains, in low relief elements (depressions, valleys, estuaries) under cereal-forb vegetation. Groundwater occurs at a depth of 3 ... 6m. Meadow chernozem soils are semi-hydromorphic analogs of chernozems. They are distinguished by a darker color of the humus horizon, increased humus content, elongation of the humus horizon, and the presence of deep gley.

According to the type of water regime, the severity of hydromorphism, soils are subdivided into subtypes: meadow-chernozem and meadow-chernozem.

Meadow-chernozemic soils are formed as a result of increased temporary surface moisture with deep groundwater (4 ... 7 m). The profile has the following structure: A - humus-accumulative horizon, black or dark gray, granular, loose, with increased thickness in comparison with chernozems, contains a lot of roots, molehills; the transition is gradual; AB - lower humus horizon, dark gray with a brownish tint, granular or lumpy-granular, loose, contains many plant roots, molehills, sometimes carbonate pseudomycelium is observed in the lower part. The total thickness of the A + AB horizons ranges from 50 ... 80 to 100 ... 120 cm; B - heterogeneously colored (brown with a large amount of dark gray, brown-gray humus streaks in the form of tongues to a depth of 100 ... 150 cm) transitional horizon, nutty and prismatic-nutty, may contain carbonates in the form of pseudomycelium, mole, plant roots; C to - the parent rock of yellow-brown and fawn color, there are pseudomycelium, smears of carbonates, rusty-ocher spots are observed from a depth of 2 ... 3 m.

The types of soil are subdivided according to thickness, humus content and related processes as black soil.

Due to the warm and mild climate, the southern European chernozems (Moldavia, southern Ukraine, Ciscaucasia) are characterized by an intense biological cycle, a large breakdown of the profile as a result of the activity of earthworms, and periodic washing of the profile. These soils are distinguished by a large thickness of the humus horizon with a low humus content (less than 8%), the absence of readily soluble salts and gypsum, abundant carbonate content in the form of deposits, cobwebs, veins, etc. in the upper horizons and micellar forms in the lower ones. Micellar forms of carbonates indicate migration and seasonal pulsation in soils. These soils are called "micellar-calcareous" soils.

In the chernozems of the Eastern European group, due to the drier and colder climate, the thickness of the humus horizon is less, and the amount of humus is higher (7 ... 12%); the profile is washed out of readily soluble salts only in the forest-steppe, while in the steppes at a depth below 2 m, gypsum neoplasms are observed.

The chernozems of Western Siberia are characterized by deep drips of humus along cracks formed during freezing of soils, a high humus content (up to 10 ... 14%) with a rapid decrease in its amount with depth, as well as the presence of gypsum in the steppe part.

In Eastern Siberia, the biological circulation of elements is significantly suppressed by low temperatures, therefore, the humus content in them is low (4 ... 9%), the thickness of the humus horizon is insignificant. These soils are often called low-carbonate or non-carbonate soils, since they contain little or no carbonate (powdery).

The granulometric composition of soils depends on the parent rocks and varies from sandy loam to clayey, however, loamy varieties predominate.

Chernozems are characterized by the absence of noticeable changes in the granulometric composition during soil formation. Only in podzolized and leached chernozems is an increase in the amount of fine dust fraction down the profile observed. In all soils, in comparison with the parent rock, the profile is enriched with silt. The silt of the South European chernozems is dominated by the montmorillonite group, hydromica contains less than 25%, and no kaolinite is found. In the Eastern European chernozems, hydromica minerals and hydromica-montmorillonite mixed-layer formations prevail. Minerals of the kaolinite and chlorite types are present in very small quantities. The micromorphology of clay matter is closely related to the depth of occurrence of carbonates in the profile. In soils in which the carbonate horizon follows the humus one, the clay substance is coagulated together with humus and is fixed. Subsidence of the carbonate horizon entails peptization of clay and some movement of it along the profile.

Chernozems are characterized by friability, high moisture content, good water permeability. The structural composition of virgin chernozems is dominated by water-resistant granular aggregates, which is especially pronounced in typical, leached and ordinary chernozems. Podzolized and southern chernozems contain less water-resistant aggregates. When using chernozems in agriculture, there is a decrease in the content of lumpy-granular, granular, dusty fractions, a decrease in water resistance and a decrease in the size of structural units.

Chernozems are characterized by a high humus content in the humus-accumulative horizon A, which gradually decreases with depth, with the exception of the soils of Eastern Siberia (table). The amount of humus in chernozems ranges from 3 ... 5% (reserves are 270 ... 300 t / ha) in the southern to 5 ... 8% (450 ... 600 t / ha) in a typical southern European group, from 4 ... 7% (300 ... 450 t / ha) in the southern up to 8 ... 12% (600 ... 750 t / ha) in typical Eastern European, from 4 ... 6% (200 ... 300 t / ha) in the south up to 10 ... 12% (450 ... 500 t / ha) in typical Western Siberia, from 3.5 ... 5.0% in the south to 5 ... 7% ( 200 ... 300 t / ha) in leached Eastern Siberia. The humus composition of horizons A and AB is dominated by black humic acids associated with calcium. The amount of humic acids associated with R2O3 and clay fraction is insignificant. Ratio Stk: Sfk = 1.5 ... 2.6. In chernozems, in comparison with other soils, fulvic acids are the lightest, with the lowest optical density and an insignificant content of the aggressive fraction.

The reaction of soils is weakly acidic or close to neutral in the humus horizons of leached and podzolized chernozems, or neutral and slightly alkaline in chernozems of other subtypes. In the lower horizons, the reaction of soils is predominantly slightly alkaline, less often alkaline.

Zone	Chernozem	Humus content,%	Humus stock, t / ha
Southern part of Europe	Yuzhny	3...5	270..	.300
	Typical	3...8	450..	.600
Eastern part of Europe	Yuzhny	4...7	300..	.450
	Typical	8...12	600..	.750
Western Siberia	Yuzhny	4...6	200..	.300
	Typical	10...12	450..	.500
Eastern Siberia	Yuzhny	3,5...5	200..	.250
	Leached	5...7	200..	.300

Chernozems have a high absorption capacity (50 ... 70 mg equiv / 100 g of soil for loamy varieties), a significant saturation of the absorbing complex with bases, and a high buffering capacity. The composition of exchangeable cations is dominated by calcium, then magnesium (15-20% of the total). In podzolized and leached chernozems, hydrogen is present in the absorbing complex. In ordinary and southern chernozems, in addition to calcium, sodium is present in the composition of absorbed cations, and the magnesium content increases.

The soils are characterized by a significant gross nutrient content. For example, in typical heavy loamy chernozems, the amount of nitrogen reaches 0.4 ... 0.5% (10 ... 15 t / ha), phosphorus - 0.15 ... 0.35%. The content of mobile forms of nutrients depends on the climate, agricultural techniques and cultivated crops. Most of them are found in the arable layer of cultivated chernozems.

Chernozem is one of the most fertile soils. This is a kind of separate ecosystem, widely used in all regions of our country. That is why it will not be superfluous for gardeners to know what black soil is, what characteristics it has and how it differs from other types of soil.

Chernozem is created only by nature. It is impossible to make artificial black soil using various fertilizers. It is formed in natural areas dominated by a temperate continental climate. The place of formation of chernozem is loess-like loam or clay, loess. The necessary conditions for its formation: periodic changes in humidity and temperatures, the suitability of the soil for the life of microorganisms and invertebrates, abundant and perennial herbal vegetation. But nowadays, you can buy black soil in the Moscow region with the supply of soil to any region of Russia, which expands the possibilities of summer residents to improve the soil in their personal plot.

Characteristics of chernozem

The main characteristics of this soil are:

• lumpy structure (the soil "breathes" and passes moisture well);
• high humus content (the soil does not have time to quickly deplete);
• a high percentage of calcium content (absolutely all plants need it);
• balance and easy accessibility of trace elements useful for plants (iron, nitrogen compounds, phosphorus, sulfur);
• neutral or near-neutral acid-base reaction (suitable for more plants);
• as a consequence of all of the above, the high fertility of these soils.

There are five main varieties of this soil:

• ordinary chernozem (they have a more lumpy structure, good moisture capacity);
• southern (with the highest humus content);
• typical (has the most striking basic characteristics of such soils, the most balanced chernozem);
• podzolized (has a slightly acidic reaction and a small supply of humus);
• leached (contain a lot of calcium and magnesium).

Distinctive features of chernozem

What are the differences between manure, humus and peat from black soil? Manure is a waste product of animals and birds. Humus is formed from manure due to its overheating and treatment with worms, insects and microorganisms for a long time. Chernozem is initially a fertile layer of soil, and humus and manure can be called fertilizers to increase its fertility.

Peat, like black soil, is formed due to the decomposition of plant residues. But this decomposition occurs in marshy areas, and its main plant component is moss. For these reasons, chernozem can retain moisture, but peat cannot.

Real, undiluted chernozem has a rich black color and a coarse-grained or lumpy structure. If you wet it, then in terms of properties it will resemble clay: the same consistency and a long drying process.

A distinctive feature of this soil is a greasy mark on the hand, after the compression of a lump of black soil. This is due to the high percentage of humus content in it.

People who have a summer cottage or their own vegetable garden know that they cannot find soil better than black soil. It contains a lot of humus and nutrients. However, many people forget that everything loses its properties over time. And even black soil sooner or later will have to be "fed" with fertilizers.

Fertilizing vegetable and flower crops with chernozem is not recommended. They have a too weak root system, so the soil may soon be compacted, which means that the air and water permeability indicators of chernozem will drop sharply.

Most often, summer residents use a mixture of black soil, peat and simple garden soil. Ornamental perennial plants get along well in the soil with chernozem introduced into it, and it is also often used when planting plants in greenhouses and greenhouses.

Chernozem is dug up only with a pitchfork to maintain its density. To restore the acid-base balance, lime or wood ash is added to the weakly acidic black, and fertilizers with high acidity are added to the weakly alkaline.