The excavated soil section is prepared for description. To do this, the front wall is cleaned, cutting the soil evenly with a knife or shovel from top to bottom, then the wall is cleaned (prepared) with a knife or chisel to give the soil a natural structure, disturbed during excavation work. A measuring tape is fixed to the front wall at the level of the soil surface. The soil section is assigned a number (name) and its morphological description is made in accordance with the established form.
Immediately after excavating the soil section, its depth is recorded and the source rock is determined. At the same time, along with the mineralogical composition, the origin (genesis) of the parent rock is indicated.
In UUOL UGLTU, in particular, the following source rocks are most often found:
Eluvium is an unsorted, slightly altered material found on the upper parts of slopes and watersheds;
Colluvium is a sorted, alluvial material found in the lower parts of slopes;
Eluvium-deluvium is a poorly sorted, transitional material between eluvium and colluvium. Confined to the middle part of the slopes. Most often these are products of the destruction of granite and gneiss.
The name of the soil is given after studying the profile, usually along the front, taking into account the sides. The front wall is divided into genetic horizons based on color, structure, mechanical composition, humidity, density and other morphological characteristics. The morphological description of the soil profile begins with the upper horizons.
In forest soils, on the surface, as a rule, there is a horizon of dead plant residues - forest floor (Ao). If the thickness of the forest litter horizon exceeds 3-5 cm, then it is divided into a number of subhorizons according to the degree of decomposition of organic matter Ао´, Ао´´, Ао´´´. For each forest litter subhorizon, the thickness, color, composition and degree of decomposition are indicated. In any soil, the Ao horizon serves as a bank of dead organic matter. The complete year-round absence of forest litter indicates soil degradation.
The transformation of dead organic matter and the accumulation of nutrients assimilated by plants occurs in humus-accumulative horizon A1 which lies under the forest floor. The humus-accumulative horizon is characterized by a dense penetration of plant roots. Depending on the humus content, its color varies from light gray to black. The humus-accumulative horizon, as a rule, has a water-resistant, lumpy or granular structure. Other types of structures in this horizon indicate unfavorable soil-forming factors. For example, spittiness indicates dry soil, and blockiness indicates waterlogging. In both cases, the presence of peat indicates a strong degree of inhibition of the humus-accumulative process.
Next, alluvial horizon (A2) has index 2 not because it lies under a horizon with index 1, but because it differs from the overlying humus-accumulative horizon in the soil-forming processes occurring in it, which reduces to the leaching of both organic and inorganic mobile substances. May be absent in some soils. The eluvial horizon is characterized by pale-whitish, gray-whitish, bluish-whitish or whitish colors, as well as platy, scaly, dusty or completely structureless, lighter mechanical composition compared to the underlying horizon.
Mineral subsoil horizon (B) in soils where mobile substances are washed out from overlying horizons (podzolic soils, malt, etc.), it is illuvial. In other soils (turf, brown forest, etc.) this horizon is called transitional. Horizon B is located in the middle part of the profile and differs from the overlying and underlying horizons by its brown color, higher density and heavy mechanical composition, the presence of new formations, and a nutty structure. The B horizon in soil science is one of the most complex and complex concepts. For example, it combines both illuvial processes, i.e. processes of leaching of substances from overlying horizons, as well as metamorphic ones - leading to transformation of the mineralogical composition in place. The B horizon can reach great thickness, so it is often divided into subhorizons B1, B2, B3, etc.
Gley horizon (G)- a mineral horizon formed under conditions of constant excess moisture. This horizon is characterized by dull bluish, bluish, greenish (olive) colors, sometimes with rusty spots. The structure of the gley horizon is blocky, less often granular, dense in composition, often of heavy mechanical composition.
Mother breed (C)- subsoil horizon, i.e. horizon underlying any of the soil horizons described above. This horizon is slightly modified by soil formation processes and has features inherent in the rock from which it was formed.
Horizon D- underlying rock. It is distinguished if its properties differ from the soil-forming horizon C.
Establishing the boundaries of the described genetic horizons is a rather difficult task, since some areas of the soil profile combine characteristics of two horizons. In such areas, transitional or intermediate horizons of type A are distinguished 0 A 1 , A 1 A 2 , A 2 B, BC, etc. If the main horizon exhibits weak signs that are not characteristic of a given horizon, for example, gleying in the A1 horizon or boiling from acid in the B horizon, then when designating the horizon, indices are added to the main letters, in particular “ g" And " To"(A1g and Bk).
After identifying the genetic horizons, they begin a morphological description of each of them.
Schematic drawing of the section should reflect its main morphological features. The drawing is painted with strokes of damp soil.
Power The genetic horizon is determined using a centimeter tape. The soil surface is taken as the starting point of the report. The column indicates the upper and lower limits in cm.
In a collumn " coloring» indicate the fundamental tone, intensity and hue of the horizon. Usually they use complex (double, triple) names such as dark gray, whitish gray, etc., where the last word indicates the predominant (background) color.
By the nature of the transition from one horizon to another distinguished: sharp - the color of one horizon changes to the color of another within no more than 2 cm, clear - 2-5 cm, gradual - 5-10 cm. Sometimes soil horizons go into other types of “tongues”, “drips” or “pockets” .
Mechanical composition of the soil- this is the relative content of particles of different sizes in it: stones, sand, clay, dust. To determine the mechanical composition of the soil in the field, a small amount of soil is moistened and kneaded to a dough-like state. Then roll the sample with your palms into a cord with a diameter of up to 3 mm and try to roll this cord into a ring with a diameter of up to 3 cm. The type of sample is an indicator of the mechanical composition of the soil (Table 1).
Table 1: Determination of the mechanical composition of soil using the wet grinding method
Soil structure- this is the ability of its solid phase to aggregate and naturally disintegrate into lumps of various shapes and sizes. From the point of view of fertility, the most valuable are water-resistant structural aggregates measuring 1-3 mm, i.e. aggregates that do not disintegrate in water, since they are impregnated and glued together with soil colloids.
To determine the structure, take a small sample of soil from each horizon and toss it on the palm of your hand until it breaks down into structural aggregates. Then the type, genus, type of structure is determined (Table 2). Similar to color, when describing the structure, complex names are most often used: lumpy-granular, nutty-prismatic, leafy-lamellar, etc. At the same time, the predominant structure is also reflected in the second word.
Table 2: Classification of structural aggregates in soils
Soil composition- this is the degree of its density and porosity. The following types of addition are distinguished by density: - very tight- the soil does not lend itself to a shovel; when digging a cut, use a crowbar or a pick; - dense- the soil is difficult to shovel, falls from the shovel in clumps and breaks up into large lumps, the knife hardly penetrates the soil 5-6 cm; - dense- the soil crumbles or easily breaks into large lumps, plates, the knife enters the horizon with little effort; - loose- the soil crumbles into small lumps, the knife enters the horizon without effort; - crumbly- the soil is loose, devoid of humus.
An important morphological feature of the soil is neoplasms- accumulations of various substances that are formed and deposited in its thickness as a result of the soil-forming process.
Neoplasms- chemical compounds occur in the form: films- thin highly dispersed surface formations on the edges of structural units, walls of pores and cracks (humus, clay, ferruginous films); raids- loose diffuse films in the form of efflorescences, powders, powdering (easily soluble salts, carbonates, silicon compounds); nodules- voluminous new formations, solid, having a clear boundary with the bulk of the soil; acquisitions- in contrast to nodules, formed by loose material and not having clear boundaries with the soil mass. Differ from the main soil background.
Inclusions- bodies of organic and mineral origin located in the soil, but not associated with soil-forming processes (large rock fragments, pebbles, boulders, animal bones, shells, pieces of coal, brick, glass, etc.). Plant roots are also inclusions, but are described separately and in more detail. When describing, note, in particular, their number, size, and depth of penetration.
Soil moisture- a very variable property depending on weather conditions and is described only on fresh sections. There are 5 degrees of humidity: - dry soil- dusty, moisture is not felt, i.e. the hand does not get cold; - fresh- does not generate dust, is cool on the hand, and when squeezed, forms lumps that are easily sprayed; - wet- moisture is felt to the touch, sticks together when compressed, the lump moistens the filter paper, becomes lighter when it dries; - raw- when squeezed, the hand becomes damp, the soil takes on a dough-like shape, but the resulting drops of water do not seep between the fingers; - wet- when compressed, water oozes between the fingers, and water also oozes from the walls of the cut.
Based on the description of the soil section obtained in this way, we begin to characterize the features of the soil-forming process. In the conditions of the Middle Urals there are podzolic, soddy, bog and brown soil formation.
In the name of the soil, the main soil-forming process is entered in the “type” line. The concept of “subtype” is isolated in the “type” of a group of soils in which individual characteristics characteristic of other types are noticeable.
The concept of “genus” is used to characterize soil characteristics that are associated with the characteristics of parent rocks.
The concept of “species” is used to indicate the degree of development of the main and overlapping soil-forming processes.
The name of soils, to some extent, should reflect their fertility and ability to be cultivated. The last two properties of the soil are closely related to its mechanical composition. Therefore, soil variety refers to the mechanical composition of the upper horizons.
Day 4-5: Receiving a task
for mapping. Analysis.
On the fourth and fifth days of soil science practice, we independently carried out a field survey of soils in the area of one block of the Ural educational and experimental forestry enterprise. Our team was given quarters numbered 13 and 14. In this quarter we laid 10 soil sections in different areas with different forest conditions. Also, 9 excavations were laid, on which soil types were checked in sections in which no soil sections were laid. The results obtained are summarized in tables.
Morphological characteristics of soils are the main diagnostic indicators for a soil scientist, according to which he assigns the soil to a certain classification unit. “The external properties of the soil are so characteristic that in the vast majority of cases, soils can be recognized or determined by them,” wrote N. M. Sibirtsev at the end of the last century.
The fundamentals of the study of soil morphology were developed by the largest Russian soil scientist S. A. Zakharov. Currently, the doctrine of soil morphology is most fully and at the modern level presented in the textbook by B. G. Rozanov.
The description of the section begins with the division of the soil profile into genetic horizons and their designation with the corresponding indices. To better identify the boundaries of genetic horizons, their transitions and characteristic features of the morphological structure, half of the cut wall is prepared using a knife. On the rough wall of the section, the tonality of the color, the structure of the soil, and the nature of the new formations stand out more clearly. When describing the incision, it is necessary to carefully examine all three walls of the incision and compare them according to the typical severity of morphological features. Quite often, the “side” walls of a section and the “front” wall differ significantly from each other both in the thickness of the genetic horizons and in the nature of their transitions. Such heterogeneity in the structure of the soil profile is most often encountered in the zone of podzolic soils and especially in forested areas. In this case, for description it is necessary to take the wall that has the least disturbed structure of the soil profile.
The concept of a soil profile was introduced into soil science and the practice of field soil research by the founder of genetic soil science, V.V. Dokuchaev.
The formation of the soil profile occurs simultaneously with the development of the soil-forming process and under its influence. The system of soil horizons that forms the soil profile is always genetically subordinate in its development and formation. This most important aspect of the genetic connection between individual horizons was pointed out by K. D. Glinka, S. A. Zakharov, A. A. Rode, I. P. Gerasimov, M. A. Glazovskaya and others. A deep interpretation of the genetic analysis of the soil profile was given by B. B. Polynov.
In the “Soil Science Course” S.A. Zakharov wrote: “The structure of the soil is 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 connection with each other, so they can be called genetic horizons. Soil formation is expressed in the differentiation of the soil mass into genetic horizons.”
Study of soil samples
Soil research conducted with students in the vicinity of an educational institution, an environmental center, or in the area where an expedition is taking place is an integral part of a comprehensive study of nature. Ideas about the structure of local soils, their varieties and distribution in their area are a necessary basis for an in-depth study of the remaining components of the landscape - relief, vegetation and wildlife.
Properly organized soil studies will help to understand the origin and history of the development of ecosystems in a particular territory, and even assess the prospects for the development of its vegetation, water regime, and fauna.
In the field, soils are described and determined, i.e. They give them names based on their external, so-called morphological characteristics. It is believed that by morphological (external) characteristics it is possible to determine the soil in the same way as we determine a mineral, plant or animal. Therefore, in field conditions it is especially important to be able to correctly describe the soil, noting all its morphological features.
Based on morphological characteristics, one can approximately judge the direction and degree of expression of the soil-forming process, and also, which is very important, classify soils. However, due to the great complexity of soil classification and, most importantly, significant differences in soil classification systems in different countries, this article does not discuss the topic of soil identification (definition).
The purpose of this teaching aid is to initially familiarize students with the soils of their area by describing it according to morphological characteristics. An important substantive (intellectual) part of this task should not just be a description of the various soil horizons of one’s soil, but an attempt to identify functional parts (zones) in the described soil.
This methodological manual provides a general scheme for dividing soil into functional zones and the typology of soil horizons corresponding to these zones, adopted in Russia.
In cases where the Russian and international systems of soil horizon typology coincide, its name according to the international typology is indicated opposite the Russian name of the horizon.
Based on descriptions made using the unified methodology proposed in this manual, it is possible to identify, classify and compare soils described anywhere in the world.
Methodology for laying a soil section
To describe soils, study their morphological characteristics, establish boundaries between different soils and select samples for analysis in soil science, it is customary to dig special holes called soil sections.
However, any soil study, before starting to dig a section, begins with choosing a place for its establishment.
Choosing a location for a soil cut
To choose the right location, it is first necessary to carefully examine the area and determine the nature of the relief and vegetation.
If the terrain is flat, a hole is dug in its central, most typical part.
On a slope - in its upper, middle and lower parts.
When studying a river valley - in the floodplain, on the terrace(s) and on watersheds.
When conducting a comprehensive environmental survey of an area, it is advisable to lay out one soil profile in each main type of plant community.
For the purposes of this educational task, the soil profile should be laid in one, the most typical plant community of its area.
The section must be laid in the most characteristic place of the surveyed territory.
Sections should not be laid near roads, next to ditches, or on microrelief elements atypical for the given territory. (depressions, bumps, etc.).
Digging a soil incision
In a selected area of the terrain, they dig a soil incision - a hole in which three walls are steep, and the fourth descends in steps.
The size of the hole depends on its expected depth (which in turn depends on the thickness of the soil, see below) and on average is 1x2 meters.
The narrow side of the incision will be the so-called front (facial) wall of the incision, which is intended for description and subsequent sampling (if necessary). At the end of the excavation work, this wall should be facing the sun, so the cut should be placed immediately taking into account the cardinal directions.
At the beginning of work, the turf is carefully cut with a shovel and folded at a distance of 2...3 m from the future pit at one of its sides. The top part of the soil mass is also thrown here. Deep horizons are thrown in the opposite direction. 
Under no circumstances should you pile earth onto the front wall of the cut - this can lead to its contamination, destruction of the upper horizons and changes in their thickness. For the same reason, you should never walk or even step on the soil surface near the front wall of the cut.
At the end of the excavation, the anterior wall (deepest) Parts of the pit must be clear of discarded soil. To do this, at the end of the work, the entire front wall of the pit is cleaned with a shovel blade.
The width of the front wall (and the entire cut as a whole) should be sufficient for one person to work in it and usually ranges from 70 to 100 cm.
In soil science, depending on the purpose of the study, three types of soil sections are dug: main (full), half-pits and trenches.
Full sections dig to the full depth of the soil, including the upper horizons of the parent rock (up to a depth of 1...5 m, depending on the thickness of the soil); half-pits - up to the beginning of the parent rock (75...125 cm), digging - up to 75 cm.
The main sections serve for a complete morphological description of the soils, the semi-pits - for the description of the main morphological characteristics of the soils and to clarify the distribution of soil types exposed by the main sections. Digging is necessary to determine the boundaries of soil groups in places where one soil is supposed to change from another.
For the purposes of this training task, it is recommended to dig a section to the beginning of the parent rock with a depth of 20...30 cm into it. In the forest zone, the depth of such a section can presumably be 1.2...1.7 meters.
When digging a hole, it is advisable to pay attention to how the soil is dug: at what depth it is more difficult, at what depth it is easier, where it is wet and sticks to the shovel, and where it is crumbly and falls off the shovel. All this gives an idea of the physical properties of the soil and will then help in describing each of the horizons.
Work on soil research in the field begins with choosing a location for a soil pit. This is very important, since the correctness of the conclusion about the soil of the entire site depends on the correct choice of location. Before choosing a location for the cut, you need to make one or more digs.
Soil sections should not be located near roads, near the edges of ditches, in microdepressions that are atypical for a given area, etc.
When choosing a location, they are guided mainly by the topography of the site, then by the vegetation and nature of the land (arable land, hayfield, forest, swamp, etc.). Observations and experience have established that the properties and quality of the soil are very closely related to the relief.
Therefore, soil sections, as a rule, should be evenly located on all elements of the relief: on watersheds, at the beginning, in the middle and at the end of a slope, on a plain, in a river valley, etc. In this case, the study will cover a wide variety of soil types, species and varieties in the study area.
It is quite clear that the density of the location of the main soil and control sections, as well as digging areas, largely depends on the relief. The more complex the relief, the more rugged the terrain, the more varied and complex the soil cover and, therefore, the more cuts need to be made per unit area. On the contrary, in conditions of flat terrain, where the soil cover is uniform, the distance between individual cuts can be much greater, and the total number of cuts per unit area is much smaller.
So, in a small study area, which is a smooth plain, it is enough to lay one section, which will characterize the soil of this area. If the flat area is large (an extensive watershed plateau or river terrace), then it is necessary to make several basic cuts and digs. The same will be required to characterize soils on long slopes of watersheds, even if they are of the same steepness, especially in cases where these slopes are dissected by gullies, ravines and gullies.
From the point of view of the difficulty or complexity of conducting soil research, territories are conventionally divided into five categories (N.P. Karpinsky, N.K. Balyabo, V.A. Francesson, A.I. Lyakhov).
- 1) steppe areas with dissected relief and uniform soil cover; on clearly isolated relief elements, soil complexes occupy no more than 10%;
- 2) territories of category I with soil complexes occupying 10-20%.
- 1) steppe, desert-steppe and forest-steppe areas with highly dissected relief, with a variety of rocks and heterogeneous soil cover;
- 2) territories of category I with soil complexes occupying 20-40%;
- 3) territories of category II with soil complexes occupying 10-20%;
- 4) forest areas that have been significantly developed for agriculture, with a clearly dissected topography and the presence of no more than 20% of wetlands.
- 1) forest areas, little developed for agriculture, with 20-45% of wetlands;
- 2) forest areas with highly complex soils;
- 3) steppe and desert-steppe areas with soil complexes occupying 40-60%;
- 4) floodplains, floodplains, river deltas with simple cover, with less than 20% of forested and bushy areas;
- 5) mountain and foothill lightly forested areas.
- 1) forest areas with more than 40% of the area occupied by swamps, or with very high soil complexity;
- 2) mountain and foothill forested areas;
- 3) floodplains, flood plains, river deltas with complex, heterogeneous soil cover (salinization, swampiness, etc.) or with more than 20% of forested areas;
- 4) tundra areas.
The density of soil sections also depends on the scale of the topographic base on which the soil map is compiled. The larger the scale, the more detailed the soil map and the more, therefore, soil sections must be made in a certain area and, conversely, the smaller the scale, the fewer sections have to be made in the study area.
The number of soil sections laid in the study area is determined by the scale of the soil survey and. category of area according to the difficulty of conducting soil research.
To establish the density of soil sections depending on the category of terrain and the scale of survey, you can roughly use the data given in Table. 80.
Each soil section (main, control and digging) is tied by eye on the ground, marked with a symbol on the soil map, numbered with a serial number and recorded in the field journal.
After selecting a location for the soil cut, mark a rectangle on the soil surface with a shovel. The pits should be such that you can freely descend into them and work. The usual sizes of the main cuts are as follows: length 150--200 cm, width 80 cm, depth 150--200 cm. One of the walls of the pit, facing the sun (to better see the color of the soil), is made vertical, and the opposite wall is made with steps every 30-50 cm, to make it convenient to go up and down.
When digging, it is recommended to throw the soil mass onto the long sides of the hole, with the turf or topsoil layer on one side, and all the underlying soil on the other. When the pit is ready, its front wall is refreshed with a shovel, individual genetic soil horizons are established, measured and described.
After describing the soil section and taking samples, the hole must be filled up. When filling up cuts, you should first dump the soil thrown out from the depths, and then cover it again with the top layer lying on the opposite side of the hole. This is done in order not to introduce diversity and spoil the fields, since the lower layers of the soil are usually infertile and require a long period of cultivation.
Soil cuts, depending on their purpose, are divided into main (deep), half-cuts (half-pits) and trenches. The main section is established to identify the soil type and should cover the entire soil thickness, including the top of the parent rock horizon. Its depth is determined by the depth of penetration of the soil-forming process and usually ranges from 150 to 300 cm. The main sections are laid on all new relief elements, when vegetation and parent rocks change. Half-sections serve to establish the subtypes and varieties of soils in the study area and to determine the boundaries of the distribution of various soils. The depth of the half-cuts is 75-100 cm. If, when studying the half-cut, a new type of soil or a change in the parent rock is revealed, the half-cut is deepened to a full cut. Digging to a depth of 25-75 cm is done to establish the boundaries of the distribution of individual types, subtypes and varieties of soils. The average ratio between the main cuts, half-pits and trenches is 1:4:5.
The crucial point is the choice of the location of the incision. The section should be laid under conditions typical for the study area. You cannot lay a cut near roads, ditches, in the corners of crop rotation fields, along the edge of agricultural land (pasture, pasture, meadow), on a hillock or in a depression that is not typical for the entire site. Before laying a cut, carefully study the area to characterize which the cut is laid. If the area under study is a plain, the section is laid in the center of the plain. If a slope is being examined, a full cut is made in the middle part of the slope and half-pits in the upper and lower parts. Often, within one relief element, microrelief is clearly expressed, which can be especially often observed in flat, flat areas, and the microrelief here is represented by a complex of barely noticeable microhighs (hillocks) and microlows (saucer-shaped depressions). In this case, two cuts are laid: one at a micro-high, the second at a micro-low.
Cutting technique. For the cut, mark out a rectangle 120-150 cm long and 60-80 cm wide. The short side of the cut serves as the front side on which the soil is described. This side should be better lit, i.e. should be facing the sun. This cut wall, as well as its two sides, are made completely vertical. On the fourth side, steps are made to descend into the cut. When digging, the soil is thrown out to the left and right of the front wall. The mass of the upper humus horizon is thrown onto one side, and the mass of deeper horizons onto the other. The front side of the cut must not be covered with soil or trampled. After finishing the work, the cut is buried, and the mass of deep horizons is laid down, and the mass of the humus horizon is placed on top.
After excavating a section, its location is plotted as accurately as possible on a topographical basis. The main cuts are indicated by crosses in circles, half-pits - by circles, digging holes - by dots with the obligatory indication of the number. The diary contains sequential numbering of all types of cuts. To link a cut, i.e. To accurately plot its location on a topographical basis, first of all, they navigate the area on a map using a compass. The map is oriented along the compass so that the northern end of the compass needle coincides with the “N” direction of the arrow on the map. Then, taking the compass direction for the cut from any clearly visible landmark (road intersection, corner of the crop rotation field, buildings), determine the distance between them and use a measuring ruler to plot this distance in the appropriate direction. The distance is determined by eye - in steps, having previously set the price of the step (its value in centimeters). You can use the serif method. An arbitrary point is placed on a small sheet of wax and lines are drawn from it through a scale ruler to two landmarks. The wax is then placed on the topographic base so that each of these directions passes through the corresponding landmark sign. The point where the directions intersect is the location point of the cut; it is cut from the wax to the card.
On the map and in the field diary, write the section number and describe it. The serial number of the cut and its location are noted in the diary; accurately indicate the element of relief and microrelief on which the section is located (for example, a plain, a saucer-shaped depression or the middle part of a gentle slope); describe in detail the vegetation (its composition, density, height and condition), as well as the type of agricultural land; describe the parent and underlying rocks, indicating the mechanical composition, the presence of boulders, carbonate crushed stone, and easily soluble salts. The level of soil and groundwater, its quality and the nature of swamping (gleyization) - surface or groundwater - are noted. The degree of soil erosion (washed away) is also noted, and on arable land the nature of its surface (evenness, blockiness, fissuring, presence of crust) and the degree of rockiness are described. If stones (boulders) make up less than 10% of the surface of the arable land, the stoniness is considered weak, if 10-20% is considered medium, and if more than 20% is considered strong.
Draw a profile of the area and indicate the location of the cut with a cross. If the section is laid on a slope, you need to indicate the exposure and steepness of the slope, measuring it in degrees. The slope is considered very gentle with a steepness of less than 1°, gentle - 1-3°, sloping - 3-5°, strongly sloping - 5-10°, steep - 10-20°, very steep - 20-45°, steep - more than 45 °.
The front side of the cut is prepared with a knife or a small spatula in such a way as to obtain its natural fracture. Based on the nature of color, neoplasms, build and other morphological characteristics, genetic horizons are distinguished, and the boundaries between them are drawn with a knife. Then a fabric meter is strengthened along the wall of the cut so that its zero division coincides with the upper level of the soil, and the thickness of each horizon and the depth of the entire profile are measured. In the diary, they sketch the profile with colored pencils, show the depth of penetration and the nature of development of the root system, note new formations, after which boiling and gleying are examined.
The test for carbonates is carried out as follows. Throughout the entire depth, every 10-20 cm, take small pieces of soil with a knife and moisten each with a few drops of a 5% HCl solution, observing the release of CO 2 bubbles. If there is no boiling visible to the eye, you should check for boiling by ear, since with a low carbonate content, the soil only crackles under the influence of acid. Having established the boiling depth of the sample with an accuracy of 10-20 cm, it is clarified by taking samples every 2-3 cm upward from the initially found depth. To determine gleying, samples with red blood salt are made on pieces of soil removed from the cut. Blue discoloration indicates the presence of ferrous forms of iron. The depths of boiling and gleying are noted in the field diary. Then they begin a morphological description of each horizon, noting its color, humidity, mechanical composition, the nature of the distribution of the root system, structure, composition (density, porosity and fracturing), new formations, inclusions, the nature of the transition of one horizon to another. The morphological description must be done very carefully and completely. The profile can be sketched using strokes of moist soil from the corresponding genetic horizons. After the morphological description, the type, subtype and variety of soil are determined and its full name is noted in the diary.