Form of description of the soil section. Soil sections, their types and purposes

Morphological features of soils are the main diagnostic indicators for the soil scientist, according to which he relates the soil to a specific classification unit. “The external properties of the soil are so characteristic that in the vast majority of cases it is possible to recognize or determine the soil from them,” wrote N. M. Sibirtsev at the end of the last century.
The foundations of the study of soil morphology were developed by the largest Russian soil scientist S. A. Zakharov. At present, the doctrine of soil morphology is most fully and up-to-date described in the textbook of B. G. Rozanov.
Description of the section begins with the separation of the soil profile into genetic horizons and their designation with the corresponding indices. To better identify the boundaries of the genetic horizons, their transitions and the characteristic features of the morphological structure, half of the section wall is prepared with a knife. On the rough wall of the section, tonality of coloring, soil structure, and the nature of neoplasms are more clearly distinguished. When describing the section, it is necessary to carefully examine all three walls of the section and compare them according to the typicality of the severity of morphological characters. Quite often, the “side” walls of the section and the “front” wall significantly differ from each other both in the thickness of the genetic horizons and in the nature of their transitions. With a similar heterogeneity in the structure of the soil profile, it is most often found in the zone of podzolic soils and especially in forested areas. In this case, for the description you need to take the wall that has the least disturbed structure of the soil profile.
The concept of soil profile was introduced into the science of soil and the practice of field soil research by the founder of genetic soil science V.V. Dokuchaev.
The formation of the soil profile proceeds simultaneously with the development of the soil formation process and under its influence. The system of soil horizons that forms the soil profile is always genetically subordinated in its development and formation. K. D. Glinka, S. A. Zakharov, A. A. Rode, I. P. Gerasimov, M. A. Glazovskaya and others pointed to this most important aspect of the genetic relationship between individual horizons. B gave a deep interpretation of the genetic analysis of the soil profile. B. Polynov.
In the “Soil Science Course” S. A. Zakharov wrote: “The structure of the soil represents the result of its genesis, its gradual development from the parent rock, which differentiates into horizons in the process of soil formation ...”. And further: “Soil horizons are in a genetic relationship with each other, so they can be called genetic horizons. Soil formation is expressed in the differentiation of soil mass into genetic horizons. ”

Description of the soil sample by morphological characteristics

General scheme for soil description

To facilitate the descriptions, a standard soil section description form is used, which is shown on the next page.
Before starting the description, fill out the heading of the form: date, administrative and local position of the section, its position in relief (flat place, hillside or ravine, etc.)type of surrounding vegetation (name of the plant community under which the soil is studied).
It is advisable to describe the vegetation in more detail, especially the part that determines the appearance of the community (in the forest, for example, tree-shrub).

If ground water is uncovered by a soil section, then measure its depth (ground water level). If there is no water, this column is left free or a value is known here that is known by the presence of wells, wells, springs in the immediate vicinity of the section.

The column “Soil name” is left free and filled at the very end only if the national classification system is well known to the teacher and he is able to determine the type of soil studied (the procedure for determining the soil is not included in the mandatory part of the task and can be performed as desired).

Next, we proceed to the description of the morphological features of the soil uncovered by the cut.
TO main morphological features of the soilto be described in the field include: soil structure (identification of genetic horizons), thickness of soil and its individual horizons, color, moisture, mechanical composition, structure, addition, neoplasms and inclusion.

Start with a close look at the freshly cleaned wall and identify genetic horizons. (see below for their typology). On the same wall, on one third of its width, for greater clarity, the borders of the horizons are slightly drawn with a knife.

To facilitate the determination of the structure of the soil and neoplasms, as well as to determine the density of various horizons on the second third of the front wall, it is "prepared". To do this, they “pick” the soil with a wide knife, starting from the upper horizons downward with a width of about 10 cm.

A third of the front wall is left untouched, i.e. freshly peeled.

Before beginning the descriptions (it’s possible at the end), for the purpose of finalizing the final results, it is advisable to make color photographs of the section: general view and view of the front wall in full vertical length (if the incision is deep - take several consecutive shots from top to bottom).
Then they begin to fill out a table of the form, in which they place information about the described soil horizons.

In the left column of the table, a diagram of the soil profile is plotted, i.e. plot boundaries. It is not necessary to do this on a scale, as some horizons may be very thin and will not be visible in the diagram, and some, on the contrary, will be very wide and will not fit in the figure.
In the middle column of the table, opposite each of the indicated horizons, their indices and thicknesses are given, and in the rightmost, widest column, verbal descriptions of morphological characters.

Verbal descriptions lead for each horizon in a line through a semicolon in a certain order: the color of the horizon; humidity; mechanical composition; structure; addition; neoplasms; inclusion.
The verbal description of the horizon is completed by indicating the nature of the transition and the shape of the border to the underlying horizon.

Upon completion of the soil description (when all handwritten work is completed) soil smears are taken from each horizon and applied to the soil profile diagram in a place corresponding to the given horizon in the diagram.
This is done as follows.
Take a small amount of soil from the horizon on the palm of your hand, add a little water to it and rub it thoroughly to the viscosity of the batter. After that, they “stain” the finger and apply it to the circuit, slightly rubbing it in a circular motion. After this, a rounded imprint should remain on the diagram, the density of which decreases from the center to the edges.

After the description is completed, samples are taken from the section for a detailed study in the laboratory, or a soil monolith for collection (if necessary).

Soil structure (functional zones and genetic horizons)

On the front wall of the soil section illuminated by the sun, one can easily distinguish soil horizons that alternate in the vertical direction and differ in color, structure, mechanical composition, humidity, and other features.
The general view of the soil with all soil horizons is called soil structure.
Correct identification and description of genetic horizons is possible only if the researcher understands the essence of soil formation processes in various parts of the studied soil profile. To facilitate understanding of the structure of soils, we give a brief description of the functional features of the different horizons that form the soil.

The soil profile can be divided into four functional zones:

accumulative zone (accumulation zone, horizon A),
eluvial zone (washout zone, horizon A2),
illusory zone (“wash-in” zone, horizon B)
area not affected by soil formation (horizons C and D).

In the first zone, the processes of accumulation of organic residues occur, their conversion into humus and the accumulation of humus.
In the second zone, the destruction of organic and mineral substances and their leaching into the underlying soil layers occurs.
In the third zone, a regular (in layers) accumulation of substances washed out from the second zone occurs.

The fourth zone is the mineral base of the soil that has not been transformed by the soil-forming process.
Thus, the characteristics of the soil profile layers are determined, on the one hand, by the process of accumulation, transformation and top-down movement of organic substances, and on the other hand, by the initial composition of the mineral part of the soils and the processes associated with its transformations.

There are many systems for distinguishing soil horizons and their letter designations, but the common thing is that all of them designate the processes occurring in each of the soil layers. To facilitate the perception of the horizon designation system adopted in Russia, we will consider them in accordance with the four functional zones of the soil identified above.

Two layers are distinguished in the first functional zone of the soil: the upper is the organogenic layer (horizons A0, Hell, T, P)consisting of organic residues of plants and animals, and lower (horizons A or A1) - consisting of organic and mineral substances, and the organic substance is represented by humus.
The upper, organogenic layer of soil, depending on the conditions of soil formation, can be represented: in dry conditions by horizons A0 or Hell, and in wet conditions - by peat T or humus P.

Horizon A0 is the uppermost part of the soil profile, which represents plant litter at various stages of decomposition, from fresh to completely decomposed. In the forest - it's forest litter (formed by fallen leaves, needles, branches, etc.), in meadows and steppes - steppe felt or turf (Hell) - fallen stems and leaves, as well as living and dead nodes of tillering of herbaceous plants.

Horizon T is peaty, formed in very humid conditions (in swamps) and represents peat layers of different thicknesses, in which parts of the plants that formed it are distinguishable.
Horizon P is humus, forms in less humid conditions and represents highly decomposed organic residues in which parts of plants are indistinguishable (the degree of decomposition is more than 50%, and the organic matter content in this horizon is 30-70%).

The lower layer of the first functional zone of the soil profile is represented either by horizon A - or by humus-accumulative (if the process of accumulation of humus in the soil prevails over the processes of its destruction and leaching)or horizon A1 - or humus-eluvial (if, along with the accumulation of humus, the process of its destruction and leaching is also expressed).
Horizons A and A1 are the darkest colored in the soil profile; their color varies from black, brown, brown to light gray, due to the composition and amount of humus. The thickness of these horizons varies from a few centimeters (In most cases) up to 1.5 m and more (in some soil types).

The second functional zone of the soil is horizon A2 - eluvial (leaching horizon). This is the horizon from which, in the process of soil formation, a number of substances are carried into the underlying horizons or outside the soil profile. As a result, this horizon is depleted in clay minerals, one and a half oxides, and is relatively enriched in silica.
This is a highly clarified, structureless or layered loose horizon. In different types of soils, the eluvial horizon has a different name. (podzolic - in podzolic and sod-podzolic soils, salted - in malt).

In the third functional zone of the soil profile, as already mentioned, a layer-by-layer accumulation of substances washed out from the second zone occurs. The horizons included in this part of the soil are denoted by the index B and are called illuvial. Substances that are washed out from soil horizons located above, and sometimes brought by a lateral current of soil and groundwater from elevated relief elements, are partially deposited in them.

Horizon B is a brown, ocher-brown, reddish-brown, compacted and heavier, well-structured horizon, characterized by the accumulation of clay, iron oxides, aluminum and other colloidal substances by washing them from overlying layers.
In soils where there is no significant movement of substances in the soil stratum, horizon B is a transition layer to the parent rock and is characterized by a gradual weakening of the processes of humus accumulation and decomposition of primary materials.
Horizon B can be subdivided into B1 — the subhorizon with a predominance of humus coloring, B2 — the subhorizon of weaker and more uneven humus coloration, and B3 — the subhorizon of the end of the humus streaks.

Depending on the soil formation products migrating along the profile, the illuvial horizon can be enriched with various compounds - humus (Вh), sludge (Вi), carbonates (Вк), iron compounds (Вfe) or have signs of gleying (Bg).

Horizon VK is the horizon of maximum accumulation of carbonates, usually located in the middle or lower part of the profile and is characterized by visible secondary emissions of carbonates in the form of deposits, veins, pseudomycelia, white eyes, rare nodules.

In some soils, the G – gley horizon occupies a special place in the third functional soil zone. It is formed in soils with constant excess moisture. (in the so-called hydromorphic soils)for example in swamps. Due to the lack of oxygen, reduction processes occur in the soil, which leads to the formation of ferrous compounds of iron and manganese, mobile forms of aluminum (glue process).
The characteristic features of the glue horizon are bluish, grayish-blue or dirty-green color, fusion, viscosity.
The gray color of the glue horizon is usually accompanied by buffy spots formed as a result of alternating manifestations of aerobic and anaerobic processes in the soil, as well as black and dark brown spots from ferromanganese compounds.

If the signs of the glue process are manifested in other horizons, then the letter g is added to their designation, for example, A2g, Bg, etc.
The fourth functional zone of the soil profile can be represented by one or several horizons, depending on the uniformity of the properties of the mineral base of the soil at different depths.

Most often, two horizons (from top to bottom) of the mother ( FROM ) and bedrock (D).
Horizon C is a rock unaffected or slightly affected by soil-forming processes.
Horizon D is highlighted when soil horizons formed on the same rock, and a rock with other properties is located below it.

The thickness of the soil and its individual horizons

The power of the soil is its vertical extent, i.e. the thickness from its surface inland to the part of the parent rock that has not been changed by soil-forming processes.

Determining the thickness of the soil begins when digging a soil section (the conditions of this training task suggest digging a section to the depth of the mother rock and even a little deeper).
To accurately measure the thickness of the soil and its individual horizons, a centimeter tape is attached with a pin (nail) to the upper edge of the cleaned front wall (tape measure with millimeter divisions)so that the zero division exactly matches the surface of the soil.

In the left column of the soil description form, the boundaries of genetic horizons are schematically plotted with a pencil.
The index, depth, and thickness of each horizon are entered in the middle column. So, noting a particular horizon, the numerator indicates its upper and lower boundaries, and the denominator indicates its power, for example:
A0 0-20 / 20, A1 20-25 / 5, etc. With such a record, not only the depth of the horizon is visible, but also its power.

Soil coloring

Coloring is the most significant indicator of soil belonging to a particular type and is very important in their classification. The color of the soils reflects their zonal features: each soil-climatic zone has characteristic color shades of the soils. So, the soils of the taiga-forest zone have light, gray and whitish tones, the soils of the forest-steppe zone are gray and dark gray, the meadow-steppe (chernozem) are dark gray and black, the soils of dry and desert steppes are chestnut and brown tones, etc. .d.
The following three groups of compounds are most important for soil coloring:

humus (black, dark gray, gray colors);
iron compounds (red, orange, yellow - oxide iron, bluish and bluish colors - ferrous iron);
silicic acid carbonic lime and kaolin (white and whitish shades).

Soils are rarely painted in any one pure color. Soil coloring is usually quite complex and consists of several colors.
To determine the color of one individual soil horizon, you must:
- set the prevailing color;
- determine the saturation of this color (dark, light colored);
- note the shades of the primary color. For example - brownish light gray, brownish brown, light grayish-fawn, etc.

When describing the color of a horizon, it is necessary to indicate the degree of uniformity of color. For example, brownish-bluish, heterogeneous, against a bluish background, brown and rusty spots and greases.
Description of the color helps to more fully characterize the soil and evaluate it genetically.

To unify the color gamut and determine the chemical properties of soils in Russia, a color scheme has been developed ("color triangle"), reflecting the basic and transitional colors of soils, depending on the presence of the three above-mentioned groups of chemical compounds. Using this scheme allows not only to correctly determine the color, but also to make an approximate idea of \u200b\u200bthe chemical composition of the soil.

When determining the color of soil in the field, it is necessary to take into account soil moisture and the degree of illumination of the soil section.
Wet soil has a darker color than dry, so it is advisable to check the color of the soil in samples brought to an air-dry state (air dried but not in the sun).

Much also depends on the illumination of the soil by the sun.
Lighting when evaluating color should be uniform, as in the shade the soil looks darker. It is better to determine the color of the soil with high sun exposure than early in the morning or evening. (To evaluate the color of the horizons, you can also use soil smears on the soil profile diagram after they have dried).

To achieve uniformity in determining the color of soils in your area, you can compose a color scale from samples of local soils and use it as a standard in describing soil sections.

Humidity

Humidity is not a persistent sign of any soil or soil horizon, but rather is an indicator of the physical condition of the soil at the moment. However, moisture significantly affects the severity of other morphological features of the soil (color, addition, structure) and its assessment, therefore, is an integral part of the description of the soil.

Humidity is determined as follows: a small soil sample is taken from the described horizon, it is squeezed in the hand, and the soil moisture is judged by the result.
According to the degree of humidity, the soil is divided into wet - water flows out during compression; wet - wets the hand (a wet mark remains), but does not drain between the fingers, wet - moisture is clearly felt, moisturizes the filter paper; fresh (moist) - cools the hand, the soil is smeared; dry - not smeared, it feels warm to the touch, dusts.

Mechanical composition

The mechanical composition of the soil is the relative content of mechanical elements of various sizes in it. The mechanical elements of the soil are individual grains of minerals and rock fragments (primary and secondary).
Mechanical elements larger than 1 mm are called soil skeleton, elements ranging in size from 1 to 0.01 mm are called physical sandand smaller than 0.01 mm - physical clay.
Among skeletal formations, depending on size and shape, there are: cartilage, rubble, stones, gravel, pebbles, boulders.
Sand is divided into: large - 3 ... 1 mm, medium - 1 ... 0.5 mm, small - 0.5 ... 0.25 mm, dusty - 0.25 ... 0.05 mm, thin - 0.05 ... 0.01 mm).

Particles less than 0.01 mm are divided into: dust (medium - 0.01 ... 0.005 mm, thin - 0.005 ... 0.001 mm) and sludge (smaller than 0.001 mm).

The type of soil is determined mainly by the ratio of physical sand to physical clay in the soil. On this basis, four main varieties are distinguished: clayey, loamy, sand and sand.

In the field, the determination of the mechanical composition of the soil is as follows. A pinch of soil from the studied horizon is thoroughly rubbed with fingers on the palm.

Sandy loam soils are ground easily, while a small amount of soft, dusty-clay material is found. Sandy soils are completely devoid of clay particles. Clay soils are difficult to grind and, after grinding, a significant amount of dusty-clay particles appears.

The determination of the mechanical composition by touch is supplemented by rolling out moistened soil.
A small amount of soil material is moistened with water to the consistency of a thick viscous mass. This mass is rolled up in the palm of your hand into a ball with a diameter of 1 ... 2 cm. The ball is rolled into a cord with a diameter of 3 mm, which is then bent into a ring with an outer diameter of 3 cm.

If the soil is clay, the cord does not break or crack when bent into a ring.
A cord from loamy soil breaks when bent into a ring. In this case, three varieties are distinguished: heavy loam - a ring with cracks, medium - the ring breaks up when folding, light loam - the cord breaks up when rolling.
From sandy loam soil you can get only fragile, easily crumbling ball, the cord from which immediately breaks up into fragments. You cannot make a cord from sandy soil.

Structure

Under the structure of the soil understand its ability to disintegrate into individual lumps of various sizes and shapes. The structure of the soil is determined by the nature of the individual lumps into which it randomly breaks up when lightly kneading in the hands or when the soil mass is thrown out of the pit.

First of all, the soil may be structureless and structural. In a structureless state, the individual mechanical elements composing the soil are not interconnected, but exist separately or lie in a continuous cemented mass.

Structural soil is divided into separate forms or sizes. There are three main types of structure:

cuboid - structural units are uniformly developed along three axes;
prismatic - individuals are developed mainly along the vertical axis;
slab-shaped - individuals are developed mainly along two horizontal axes and are shortened in the vertical direction.

The structure is determined during the preparation of the front wall, when a small piece of soil is picked out with a knife from the studied horizon and thrown several times in the palm of your hand, a sheet of paper or a shovel until it breaks up into structural units.
Each type of soil and each genetic horizon is characterized by certain types of soil structures.
For humus horizons, for example, a granular, lumpy, lumpy-granular, powdery, powdery-lumpy structure is characteristic; for eluvial horizons - tiled, foliate, scaly, lamellar; for the illuvial - columnar, prismatic, walnut.

Addition

Under the addition of soil understand its density and porosity. They depend on the mechanical composition, structure, as well as the activity of soil fauna and the development of plant root systems.

According to the degree of density of the soil are divided into:

Merged (very dense) - when the soil does not lend itself to the action of a shovel (enters the soil no more than 1 cm); the knife is not included in it, you can only drive it. This addition is inherent in the illuvial horizons of solonetzes and cemented mineralized horizons of podzolic soils.
Dense - the soil is difficult to shovel, considerable effort is required to push the knife into the soil (included in 4 ... 5 cm), the soil is hardly broken by hands. Typical of the illuvial horizons of loamy and clay soils.
Loose - a shovel easily enters the soil, which, when thrown away, breaks up into individual lumps. This addition is observed in well-structured humus horizons.
Loose - particles of soil are not connected with each other, and the mass of soil has flowability. This addition is characteristic of sandy and sandy loamy soils.

Soil porosity is characterized by the degree of soil fracture and cavity size.

According to the sign of fracture, the following types of soil compaction are distinguished. (in dry condition):

fissured- with a cavity width of less than 3 mm;
fissured-cotton - 3 ... 10 mm;
slit-like - cavities with a width of more than 10 mm.

Based on the size of the cavities, the following types of addition are distinguished:

fine pore - the soil is penetrated by pores with a diameter of less than 1 mm;
porous - 1 ... 3 mm (Loess is an example of this addition);
spongy - voids ranging in size from 3 to 5 mm;
nasal (holey) - in the soil there are voids with a diameter of 5 to 10 mm, due to the activity of numerous invertebrate animals (gray soil);
cellular - voids exceed 10 mm (subtropical and tropical soils);
tubular - voids in the form of channels dug by large excavations (mainly vertebrates).

Neoplasms

Neoplasms are well-formed accumulations of various substances that have arisen or accumulated in the process of soil formation. Neoplasms indicate the nature of development and the direction of the soil formation process.
Neoplasms may be chemical or biological origin.

Chemical neoplasms in the soil arise due to chemical processes that lead to the emergence of various kinds of compounds. They can precipitate either at the place of formation or, moving with the soil solution in horizontal and vertical directions, at some (sometimes significant) remoteness from the place of its initial occurrence.
Precipitating due to coagulation, crystallization, or under the influence of other causes and accumulating upon repeated repetition of these phenomena, these compounds form into chemical neoplasms.

In the soil pit, chemical neoplasms can be determined by the color, shape, and compaction of the material.
Neoplasms in the form of tubes, in the form of brown grains or densely cemented ocher-colored sand are compounds of iron hydroxides.
Spots and small shot-like thickenings (nodules) of black and brown color are manganese compounds.

Mold white or off-white, white eye (white loose rounded lime accumulations with clearly defined edges with a diameter of 1-2 cm)cranes (dense accumulations of lime)dutics (too, but empty inside), nodules (large dense accumulations of lime up to 20 cm in diameter)rattles (too, but empty inside) - compounds of carbonic lime (CaCO3). Its neoplasms are found in soils of almost all zones, but the most typical forms are formed in chernozems.
Layers of marl or meadow lime are formed in lowland peatlands and swampy soils in the floodplains of the rivers as a result of the addition of calcium carbonate to groundwater and its deposition in the thickness of soil horizons.

Fine whitish powder - silicic acid compounds (SiO2). Siliceous powder - the finest whitish coating on the surface of structural units, representing small fractions of quartz and feldspars. In the podzolic horizon of podzolic soils, silicic acid permeates the entire horizon and forms separate streaks, tongues, pockets with which it is embedded in the underlying horizons.

Film or spots of dirty greenish or bluish color - ferrous compounds of iron (FeCO3, Fe3 (PO4) 2). They are formed under conditions of excessive soil moisture during anaerobic processes; therefore, they are found mainly in marshy and swampy soils. Ferrous ferrous compounds are found in the form of bluish or bluish-gray films and spots and bluish crusts on the surface of structural units and along the walls of cracks.

White crusts of different thicknesses, smears, grains and individual crystals indicate the presence of readily soluble salts - chlorides and sulfates (NaCl, CaCl2, MgCl2, Na2SO4). They are found mainly in saline soils and rocks, more often in dry semi-desert and steppe zones.

Biological neoplasms (animal and vegetable origin) have the following forms:

wormholes - winding passages of worms;
caprolites - formations in the form of small glomeruli, which are pieces of land that have passed through the digestive apparatus of worms and saturated with their secretions;
molehills - empty or filled passages of burrowing animals - ground squirrels, groundhogs, moles, etc .;
rootins - rotted large plant roots;
dendrites - patterns of small roots on the surface of structural units.

Inclusions

Inclusions are objects of organic or mineral origin present in the soil, the formation of which is not associated with the soil formation process. Inclusions include:

roots and other parts of plants of varying degrees of decomposition (rhizomes, bulbs, scrubbed crop debris and manure, forest litter, etc.);
shells and bones of animals;
boulders and other rock fragments;
pieces of brick, coal, glass, etc .;
archaeological finds (animal bones, dishes and its shards, the remains of weapons and jewelry, etc.).

Transitional nature and border shape

In concluding the description of the soil horizon, it is necessary to note the nature of its transition to the next (underlying) horizon. Transitions are: sharp - with the width of the border between the horizons within 1 cm, clear - with the width of the border 1-3 cm, noticeable - 3 ... 5 cm and gradual - the border stands out indefinitely within 5 ... 10 cm.
The very shape of the boundaries between the horizons is also to be described.

The following types of borders are distinguished:
flat;
wavy - the ratio of depth to width of streaks less than 0.5;
pocket - ratio from 0.5 to 2;
linguistic- more than 2;
squeezed - more than 5;
blurry - indefinite.
In the case of an irregular shape of the boundaries, the average of several measurements with the limit of power fluctuations is taken to establish the horizon power.

Parameter Name	Value
Topic of the article:	SOIL SECTION
Category (thematic category)	Culture

WHERE TO BEGIN? DEVELOPMENT OF THE LAND UNDER THE GARDEN

VEGETATION - INDICATOR OF SOIL PROPERTIES

Suppose you received an uncultivated or long-cultivated piece of land for your garden. First of all, you need to find out what kind of soil you got, what its properties are and, in accordance with this, develop measures for its development.

First of all, look at what is growing on it. Vegetation is a good indicator of soil properties. In the event that sorrel, sedge, buttercup, hawk, horsetail, cinquefoil, daisies, meadow cornflower, and highland mountaineer have luxuriantly grown on your site, this means that the soil is acidic and waterlogged. On slightly acidic, well-drained soil, you will see other plants: alfalfa, clover, burdock, coltsfoot, nyvyanik, bird highlander. Field mustard, goose paws, tar, thistle, clover, euphorbia, chamomile (umbilicus) indicate humus-poor compacted soil. Another group of plants, on the contrary, loves fertile, cultivated soils and immediately develops a field abandoned by a person - quinoa, thistle, wood louse, litter.

If your site has a lot of nettles, this is a good sign. Nettle roots have beneficial effects on the surrounding soil, contributing to the accumulation of thin dark humus.

After you have studied the surface of your site, you need to see what it has in depth. If you make the so-called soil section, you will get answers to many important questions at once. The soil section will give you rich information about your soil.

Dig a pit 60-70 cm deep so that one wall is strictly vertical and aligned, on the opposite side for convenience you can make one or two steps. On a vertical wall you can trace all layers, or, as soil scientists say, soil horizons that make up your soil, and determine many of their properties. Next, we describe what can be seen in the section of sod-podzolic soil, the most common type of soil in the Non-Chernozem zone of Russia.

Cut front wall

A1 - arable horizon A 2 - podzolic horizon B - illuvial horizon

Fig. 5. Soil section. Profile and front wall of a section on sod-podzolic soil

The uppermost layer, dark-colored and penetrated by roots, is the humus horizon. This is the same layer that will feed the roots of your plants. For this reason, its properties are especially important. First of all, its coloring characterizes the content of humus in it. Typically, the color of the humus horizon ranges from light brown to dark brown; the darker it is, the higher the humus content.

By the physical properties of the humus horizon you will find out which soil you got - light or heavy (in the language of soil scientists - the mechanical or granulometric composition of the soil). This will greatly help you understand what to expect from her. There is a simple test: a lump of moist soil is placed on the palm of your hand and a cord is rolled from it.
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If the cord immediately falls apart, then you have light sandy soil. Try folding the cord into a ring. If it does not crack at the same time, then you have heavy clay soil. If numerous cracks appear on the ring, it means that the soil is loamy with the most favorable ratio of sand and clay particles for agriculture. Both sandy and clay soils, each in its own way, give the gardener a lot of trouble. Sandy soils poorly retain water and nutrients, for the most part these are poorly fertile soils with organic matter. However, they also have a number of positive properties: sandy soils are almost never threatened by waterlogging and stagnation of water, and, in addition, they are warm and quickly warm up. Due to these properties, in spring they are ready for sowing before others. Heavy soils, on the contrary, are called cold, as they warm up very slowly. Οʜᴎ do not pass water well. Unstructured clay soils, when dried, turn into a solid stone, and after rains, water stands on their surface for a long time. But cultivated clay and, especially, loamy soils are rich in organic matter and have high fertility. With the right system of measures, light soils can be made highly fertile.

In the soil section, you can also see if the humus horizon has a lumpy structure and whether there are many moves of earthworms in it. Both are important indicators of fertility. Next, you can measure the thickness of the humus horizon. It is worth saying that for the normal development of plants it is required that its thickness be at least 15 cm. If it is less than 15 cm on your soil, then you will need to take measures to gradually cultivate the underlying layer and involve it in the treatment.

If your soil was once arable land, the humus layer has a clear lower boundary at a depth corresponding to the depth of plowing. If this is virgin soil, then the humus layer gradually passes into the lower-lying podzolized layer, which has a light, white-yellowish color. This is a completely barren layer with a strongly acidic reaction. The thinner it is, the better for you. When digging up a site, it should never be touched and turned to the surface. It can only be gradually cultivated, very slowly increasing the depth of digging.

Under the podzolized layer is a dark brown compacted layer, the so-called illuvial horizon. It usually accumulates mineral and mineral elements washed by rainwater from the upper horizons. And even lower, usually at a depth of more than 1 m, there is a parent rock that is not affected by soil formation, on which this soil originated. Most often it is brown loam or red-brown moraine, a trace of the great glaciation that swept the entire north and middle of the European part of Russia. Morena contains a lot of pebbles and stones of various sizes.

The presence of overmoistening is evidenced by blue-gray-gray spots and interlayers, the color of which is due to the formation and leaching of acidic forms of iron in the conditions of low oxygen access. If such spots are present in the humus horizon, this is a very bad sign indicating a high level of groundwater.

If you got a site on a former swamp, then on the soil section you will mostly see two layers. Upper, humus, very dark, high in humus or peaty, which is a layer of peaty poorly decomposed plant mass. Below is a layer of viscous dark brown or blue – clay, less often sand. This, of course, is not the best option for the garden, and even more so for fruit trees. It can only be saved by creating high embankments or beds of such a height that the root system of cultivated plants does not suffer from overmoistening from below with high-lying groundwater. And of course, it is extremely important to try to lower the groundwater level with the help of drainage ditches, which will remove excess water from the site.

The highest level of natural fertility in the Non-Chernozem zone is in the floodplain soils formed as a result of the gradual deposition of river sediments. It is worth saying that they are characterized by a deep humus horizon (up to 40-50 cm) with a high humus content. The dark brown color of this horizon gradually brightens downward in accordance with a gradual decrease in the content of humus. The humus horizon usually has a good lumpy structure and a neutral reaction.

In the Non-Chernozem zone there are a lot of soils suffering from waterlogging, and gardeners, as a rule, get far from the best areas (well, if not an open swamp). Waterlogging is often caused by the presence of a densified underlying layer. To check if your site will not suffer from waterlogging, it is recommended to do the following test. Dig a hole 15 cm in diameter and 30 cm deep. Pour water into it. When the water has completely leaked into the soil, refill it again. The second time, time should be noted, ĸᴏᴛᴏᴩᴏᴇ it takes for complete leakage of water. If it takes more than 8 hours, it means you have poorly drained soil. In case of heavy rains, water will slowly seep into the depths and the top layer will be waterlogged for a long time.

Another test will help you find out if your plants will suffer from drought, that is, find out what the water holding capacity of your soil is. A small plot of land is watered very much. After 2 days, they dig a hole 15 cm deep. If the soil has dried up to this depth, it means that it does not hold enough water to ensure good plant growth.

CHEMICAL ANALYSIS OF SOIL, ACIDITY

Now that you have learned everything that you can see with your eyes and touch with your hands, think about a chemical analysis of the soil, if you have the opportunity to do so. The soil on your site should not be exactly the same in its different parts. To get the average soil characteristics of the whole plot, make a mixed soil sample and send it for analysis. To do this, in three or four places they take the soil with a shovel, preferably to a depth of 15-20 cm, mix it and select the amount necessary for analysis. A soil sample should only be stored dry.

The most important type of soil analysis is the determination of soil acidity, or pH. The entire soil acidity scale is divided into 14 pH values. It is generally accepted that a neutral soil reaction corresponds to pH 7. At lower values, the soil has an acid reaction, and at higher values, it has an alkaline reaction. The availability of many nutrients for plants depends on the acidity of the soil. With a neutral reaction, the batteries are in the most accessible form.

Soil acidity can be determined by indicator (litmus) paper. A small sample of soil is saturated with rain or distilled water and indicator paper is applied to it. Red color of the paper indicates a strongly acidic reaction, orange - of medium acid, yellow - of slightly acidic, yellowish-green - neutral, bright green (or blue) - alkaline. Acid and alkaline reactions are unfavorable for the activity of microorganisms and, therefore, for the formation of humus from decaying plant residues. Sod-podzolic soils most often have an acidic and slightly acidic reaction. Having determined the pH of your soil, you will know whether to add lime to it to neutralize acidity. In the future, when the soil is well cultivated, a neutral reaction will be maintained in it by itself and the gardener will not have to worry about acidity. But at first, this issue needs to be solved by applying lime fertilizers, among which ground limestone, ground chalk, slaked lime and dolomite flour are the most common. The first three contain calcium carbonate, and dolomite flour contains calcium and magnesium salts. Liming is usually carried out in the fall under the main digging. The amount of calcareous material depends on the mechanical composition of the soil and on the pH value. Since vegetable crops are quite sensitive to acidity and react poorly to both too acidic and too alkaline reactions, it is important not to miss and make a dose of lime that is appropriate for your soil. In our opinion, it is safer to adhere to lower doses, since subsequent application of manure or compost͵, in turn, will help to neutralize excess acidity.

Below we give a table taken from the “Guide for the vegetable grower” (Minsk, 1984).

If you yourself will determine the pH in a water extract using indicator paper, then keep in mind that the strongly acid reaction that you received will correspond to the first two columns of the table. 1 (pH \u003d 4.5 ^ 5.0), medium acid - the third column (pH \u003d 5.1 - ^ - 5.5), slightly acidic - the fourth column (pH \u003d 5.6-nb, 0), which is close to neutral - fifth column (pH \u003d 6.1-H\u003e, 5). If liming is carried out with slaked lime, then the dose is reduced by 1.35 times. On strongly acidic soil, it is recommended to apply a high dose of lime not immediately, but in parts, so that soil organisms can gradually adapt to changing conditions.

Table 1 Estimated lime rates for vegetables based on the mechanical composition and acidity of the soil

Wood ash has an alkaline reaction and should also be used to neutralize the soil. It is recommended to make it every 2-3 years no more than 1.25 kg per 10 m 2.

Further, it would be desirable to make an analysis for the content of organic matter. We said earlier that the critical value is 2% of the weight of the soil; This is extremely important for stable soil fertility. At a lower content, certain measures are necessary: \u200b\u200borganic fertilizer, green fertilizer - more on this below. An analysis of the most important plant nutrients — nitrogen, phosphorus, and potassium — will show you which substances are deficient in your soil. Nitrogen deficiency is compensated by the introduction of organic fertilizers. Quite often there is a deficiency of phosphorus. In this case, the introduction of superphosphate is allowed in the first year͵ which will help to quickly satisfy the plant's need for phosphorus, but at the same time ground phosphorus is also introduced with the expectation of its long-term effect. Estimating the content of nutrients according to the results of chemical analyzes is possible only on soils poor in organic matter. Soils into which organic fertilizers are applied annually do not need to be applied with soluble mineral fertilizers, since they contain a significant part of nutrients in their humus.

SOIL CUT - concept and types. Classification and features of the category "SOIL SECTION" 2017, 2018.

Soil sections are of three types: main (full) sections, control (verification or semi-pits), surface (digging).

the main (full) sections are laid to such a depth as to reveal the upper horizons of the unchanged parent rock. Usually this depth is on average 1-2 meters. Such sections serve for a special detailed study of the morphological properties of soils and sampling for physical and chemical analysis.

Control sections are laid to a shallower depth from 0.75 to 1.5 meters. They serve to study the power of humus horizons. If the description of the half-pit revealed new signs not previously noted, then at this point it is necessary to lay a complete section.

Surface cuts are usually laid in the places of the supposed change of one soil to another. Depth ranges from 0.40 to 0.70 meters.

The section is usually positioned so that its front wall intended for description is facing the sun in order to avoid sun glare interfering with the correct assessment of the soil. Three walls of the cut should be vertical, the fourth with steps. The soil of the cut must be thrown to the sides and not to the front. The upper (humus) horizon is thrown out on one side, and the lower layers on the other side of the section so as not to mix with the upper fertile layer.

General view of the soil section

Immediately after the description and sampling, it is necessary to carefully fill the incision.

7. Morphological description of the soil section

Section No. 1 Ivolginsky Basin in the vicinity of the village of Kalenovo

horizon name	Power cm	description
A 0 forest litter		Does not boil from HCl; there is poorly decomposed needles, branches, leaves; loose; dry; smooth transition;
A1 Humus Accumulative		The border is expressed along the border of the roots; the color is brown; dense; structural aggregates penetrated by the roots are lumpy; does not boil from HCl; Fresh semi-decomposed tree roots are found; a slightly acidic reaction of the medium; the transition border is wavy, expressed by color, by roots;
		The color is brown, dense, the horizon is penetrated by roots, the structure is lumpy, does not boil from НСI
[A] Interment layer		The transition border is wavy; the color is green-gray; the horizon is sealed; small roots are found; lumpy structure; does not boil from HCl; dry; wavy transition;
		Not uniformly colored; the main background is yellow-gray; glimpses of sandy loam composition; does not boil from HCl;
		Coloring not uniform yellow-gray; roots are found; boils violently from HCl; dense; lumpy; fresh;
		The color is yellow; carbonate deposits are present; it boils violently from HCl; dense horizon; fresh;

Section 2 of Ivolginsk village, 150-200 m in the West direction from the Ulan-Ude - Kyakhta Federal Highway, on arable land.

horizon name	Power cm	description
Arable		Dark brown, dense, small roots are found, the structure is not strong, lumpy, fresh, the border of the transition point is dark wavy, expressed in color
In chestnut		Dense, dirty yellow, there are single roots, does not boil from HCl, the transition boundaries are smooth, expressed by boiling
		The color is dirty yellow, heavy composition, dense
		Dry, there are single roots, there are inclusions, lumpy

Classification of soil sections 1 -2 m 75 -125 cm

Field equipment of soil scientist 1. 2. 3. 4. a) b) Shovels (shovel, bayonet, small sapper); HCl soil drill; Crowbar, pickaxe - for work on stony and dense soils Field bag: Knife, chisel - preparation of the soil section wall and sampling; Measuring tape - measuring the thickness of soil horizons. Set so that the 0 mark of the tape coincides with the surface of the soil; c) 10% hydrochloric acid in a dropper - determination of the depth of boiling (the presence of carbonates in the soil); d) Geological hammer (if soils are examined in mountainous areas); e) water; f) Files and whetstones for tool sharpening; g) Packaging materials for soil sampling; h) camera; i) Office supplies; j) Compass, GPS - measuring tape, sample collection bags.

Methods of orientation in the field Glazomer - the ability of a person to evaluate by eye, without the help of instruments, the distance to surrounding objects and the size of objects. At a distance of 1 km, the error is 50%, but at shorter distances it can not exceed 10%. The distances established by eye methods are checked on the map or directly by steps or using GPS, GLONAS global positioning systems.

Measuring distances in steps A wound is usually long in steps of half human height, counting to eye level, i.e., an average of 0, 7 -0, 8 m. To increase the accuracy of measurement, you must know the stride length in meters. For this, a previously known distance is measured twice in steps (at least 250-500 m). Having thus determined the length of your step, multiply by the number of steps and obtain the distance to the object

The accuracy of eye measurement of distances largely depends on the weather, terrain, nature of the surface, size and color of local objects

Choosing the location of the section The full-profile section must be laid in the most characteristic place. When laying the section, it is necessary to take into account: 1. The places of the sections should be coordinated with the relief and state of vegetation; 2. The heterogeneity of the soil cover is affected by the economic use of the territory. At a selected location with a shovel, a rectangle is drawn with sides approximately 150-200 cm long and 70-80 cm wide. One of the walls of the section should be facing the sun. This wall is called the "front." It is intended to study the soil section.

Laying and description of soil sections Side wall Front wall Steps Dimensions approximately 150 -200 × 70 -80 × 200 cm

Preparation of the front wall I II 1. The front wall is aligned with a sapper or bayonet shovel; 2. a part of the front wall is prepared from the surface to the bottom of the cut

Isolation of soil horizons A B C Having examined the general change in morphological characteristics along the soil section, genetic horizons are identified. The structure of the soil profile reflects the main processes occurring in soils and determines the classification position of the soil

Determination of the thickness of soil horizons 0 -37 37 A 10 cm 37 -81 44 81 -130 49 V C 10 cm

Determination of moisture 1. Dry soil - dust; 2. Fresh - does not dust, slightly cools the hand; 3. Wet - compressed by hand into lumps, paper applied to the soil quickly dries; 4. Raw - moisturizes the hand and sticks to it; 5. Wet - water trickles from the walls of the section; Humidity is not a stable sign of a particular soil or individual horizon and depends on: ü meteorological conditions; üphysical properties of soils; ü vegetation;

Determination of soil color. Color is the most accessible morphological feature of soils; in natural conditions, soil color varies greatly depending on moisture and the nature of lighting. You can not describe the soil early in the morning and in the evening with a low position of the sun, as well as in a wet and wet state

Determination of particle size distribution of soils Determination of particle size distribution is an important step in the description of a soil section. Based on the particle size distribution, the lowest taxonomic units of soils — varieties — are established. The most accurate determination of HMS is made by laboratory methods (Kaczynski method with sodium pyrophosphate), sieve method. In the field using methods: 1. dry grinding; 2. wet grinding; 3. rolling (cord method);

Classification of mechanical elements by size (according to N. A. Kachinsky) Stony part of the soil Gravel Sand: coarse medium fine Dust: coarse medium fine Silt: coarse thin Colloids EHF diameter, mm EHL groups *\u003e 3 Skeleton (cartilage) 3 -1 1 - 0, 5 -0, 25 -0, 05 -0, 01 -0, 005 -0, 001 -0, 0005 -0, 0001 0, 01 Physical clay

Determination of granulometric composition by rolling method Granulometric composition Result of rolling into a cord Sand does not roll into a ball Sandy loam forms rudiments Light loam cord forms, but breaks up into pieces Middle loam continuous cord, but when rolled into a ring it breaks into pieces Heavy loam cord is continuous, but when coagulation in a ring on its outer surface cracks are formed. Clays are a continuous cord that coils into a ring without cracks. Type of sample after rolling

Determining the structure of soils. Structure - the ability of the soil to decompose into structural units that vary in size, shape, density, water and mechanical strength. When determining the structure, a classification developed by S. A. Zakharov is used. The structure usually varies greatly in profile. In wet and wet soils, the determination of the structure is difficult; in this case, the structure is determined in dried samples.

Determination of soil composition Addition - external expression of soil density and porosity 1. 2. 3. 4. 5. Loose addition; Loose compaction; Compacted addition; Dense addition; Very tight addition.

Soil porosity 1. fine-porous - the soil is penetrated by pores with a diameter of less than 1 mm; 2. porous - the pore diameter ranges from 1 to 3 mm; 3. spongy - in the soil there are voids from 3 to 5 mm; 4. nostril, or holey - the diameter of the voids varies from 5 to 10 mm; 5. cellular - the diameter exceeds 10 mm; 6. tubular or tubular - voids in the form of channels dug by excavations: mole rats, ground squirrels, moles, etc.