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Programmed Job 2

All soil properties related to the category of physical can be divided into basic and functional. The first group includes specific and volumetric gravity, plasticity, hardness, porosity, cohesion, ripeness and stickiness, and the second group includes air, water and thermal characteristics.

Water properties reflect the ability of the soil to absorb, pass and retain moisture coming in the form of precipitation or irrigation water, as well as transfer it from the deep layers to the surface, to plants. Moisture can have a significant impact on the chemical, physical, air and thermal qualities of the soil. The physical characteristics of the soil, being in close connection with its other properties, are determined by the process of soil formation, which, in turn, varies depending on the basic and functional qualities.

Volumetric and specific gravity

The volumetric weight of the soil is usually called the unit volume of dry soil in its natural composition. To determine this parameter, a soil sample is weighed, which has an undisturbed structure and a certain volume.

Specific gravity is a unit of weight of a solid mass of soil without pores. This is an expression of the ratio of the weight of the solid phase of the soil of a given volume and the weight of water, which has the same volume and a temperature of 40 ° C.

Porosity

Porosity, or duty cycle, is the total pore volume between the components of the solid phase of the soil, which is expressed as the ratio of soil volume to pore volume.

The size of the pores, their compatibility and shape can be varied, since they are formed as a result of random interaction of polydisperse particles. The gaps formed between them usually also differ in surface quality. Their main characteristics - shape and size - can change over time due to biological, mechanical and physical processes occurring in the soil. At the same time, some pores may completely disappear, while others may only form. Often in the soil there is a so-called compacted laying, which leads to the filling of pores with aggregates having the same diameter.

Plastic

Soil plasticity is its ability, when a certain moisture level is created, to change its original shape and maintain a new, given one. It gets this quality due to the formation of hydrated compacted shells that form around its small particles. Oily clay has the maximum plasticity indicators, the structure of which includes the finest scaly particles arranged in layers - one on top of the other.

stickiness

Stickiness is a property of the soil, in which it, being in a wet state, sticks to the surface of objects in contact with it. The indicators of this parameter are mainly determined by the composition of the soil and its level of moisture. Stickiness can manifest itself at a moisture content of 40 to 60% in structureless soils and from 60 to 70% in structural ones.

Under the condition of further moistening, it passes into the category of fluidity, and when the material is dried, this property may be completely lost. Thus, we can say that stickiness is the quality of the soil, which depends on the level of moisture at the appropriate time.

Connectivity

Connectivity is a term that denotes the property of the soil, expressed in the connection of its constituent particles. To measure this value, indicators of the force are used, which contribute to the retention and adhesion of particles to each other. Connectivity depends on the cohesion, adsorption, degree of soil moisture and its cementing ability, which, in turn, is determined by the structure and composition of the soil.

Hardness

Hardness, or density, is the degree of soil resistance to the action of a solid object. Based on this parameter, soils of the following types are distinguished:

- loose (soil particles easily slide off the surface of the influencing object);
- loose (has a slightly lower flowability);
- compacted (the degree of resistance of such soil to the subject of impact can be called satisfactory);
- solid (soil particles stick to the surface of the active object, and the cut walls remain dense);
- very hard (cannot be cut with a shovel or knife).

The structure of soil horizons is heterogeneous. In it, even with the naked eye, you can easily see various cells, cavities, cracks and pores. These soil components vary in size and shape. One of the classifications of soils is based precisely on the shape and size of voids and pores. Thus, the following types of soils are distinguished:

- finely porous (pore diameter does not exceed 1 mm; they are a sign of loess and soils formed from them);
- porous (pore diameter is from 1 to 3 mm; they are considered a sign of loess rocks, gray soils and soddy-podzolic soils);
– spongy (pore diameter reaches 5 mm; found in podzolic horizons);
- perforated, or porous (pore diameter is 5–10 mm; they are a characteristic feature of gray soils; they are formed as a result of the vital activity of digging animals);
- cellular (pore diameter is not more than 10 mm; such soils are located in tropical and subtropical zones);
- tubular (pore diameter exceeds 10 mm; the formation of such soils is due to the vital activity of large digging animals).

In appearance, the cavities that make up the structure of a particular type of soil can be different:

- slit-vertical (voids with a diameter of more than 10 mm; located mainly in the columnar horizons of solonetsous soils);
- fissured (cavities look like cracks ranging in size from 3 to 10 mm; they are found in columnar and prismatic soils);
- finely fractured (cavities less than 3 mm in size, have the form of cracks directed along vertical lines).

Soil crust and plow pan

Speaking about the physical qualities of the soil, one should also mention such phenomena as soil crust and plow pan. The first is often formed after intensive wetting on the surface of areas with clay and loamy soil. Such a crust is a swollen layer of an arable cut of the soil, dotted with vertically located cracks. It contributes to the release of a significant amount of moisture from the arable layer of soil, which leads to a decrease in the germination of sown plants, slowing down their growth and development. In general, soil crust reduces crop yields.

A plow, or arable, sole is an area that is formed at the level of the subsurface horizon on clay and loamy soils. This phenomenon also negatively affects the yields of crops grown in such areas. To eliminate the plow pan, it is recommended to change the depth of digging or plowing, as well as carry out measures for gypsuming alkaline soils or liming - acidic.

Water qualities

Water can be attributed to the group of main factors that have a significant impact on the nature of soil formation. In addition, a sufficient level of humidity is an important condition for their fertility. Water is of particular importance as a component of land reclamation measures.

As you know, the low level of soil moisture causes a low yield of crops grown on them. For cultivated plants, it will be satisfactory only if it is possible to achieve a balance between the content of water and nutrients in the soil, and also to create a favorable temperature and air regime for them.

The level of soil moisture depends not only on the climatic conditions of a particular area. To a large extent, it is also due to such soil quality as water-holding capacity. It is possible to achieve sufficiently high indicators of soil quality using various methods of its cultivation. It is important to saturate it not only with mineral and organic substances, but also with moisture. To do this, it is necessary to improve soil parameters such as moisture, moisture capacity and water permeability.

Humidity

The level of moisture in the soil can vary from waterlogging to complete desiccation. This term should be understood as a certain amount of water that is noted in the thickness of the soil at a given time. The moisture level is expressed as a percentage relative to the dry soil clod.

In the event that the degree of soil moisture is known, it will not be difficult to establish the volume of the moisture reserve. It is known that in one area the soil can have different levels of moisture, which depends on the depth of the soil layer. In addition, this indicator is due to water resistance, capillarity, moisture capacity and other factors that affect moisture content.

The level of soil moisture can be regulated using special agrotechnical methods. When using them, it is imperative to take into account the rate of change in the degree of soil moisture, which varies when moving from one layer to another.

There are also concepts of absolute and relative soil moisture. In the first case, the amount of moisture in the soil in a particular area at a particular point in time is implied. It is expressed as a percentage of the volume or weight of the soil. Relative humidity is an indicator of moisture content, depending on the porosity of the soil.

moisture capacity

Moisture capacity, or moisture retention, is a property of the soil, manifested in the ability to retain and absorb the maximum amount of moisture. This parameter is determined by the level of humidity, soil temperature, its structure, composition and quality of cultivation. At the same time, the moisture capacity and temperature of the soil and the environment are inversely related. The higher the latter, the lower the moisture content. The only exceptions are soils rich in humus.

The indicators of moisture capacity of soils at different levels are different. There are several types of moisture content:

– maximum (adsorption);
- complete;
- capillary;
– minimum field;
- marginal field.

All of them are transformed depending on the nature of the development of the soil layer in natural conditions and the characteristics of the measures taken to cultivate it. It was noticed that a single loosening of the soil can significantly increase its water characteristics.

The improvement of water properties is also facilitated by the enrichment of the soil with organic and mineral fertilizers (peat, manure, compost), which are distinguished by high water-holding qualities. In addition, water-retaining substances characterized by a high degree of porosity are often used for the same purposes. These include expanded clay, perlite and vermiculite.

Heat capacity

In addition to the natural thermal energy emanating from the sun, the soil receives heat, the source of which is substances that enter into a physicochemical, exothermic or biochemical reaction. However, this does not cause changes in the temperature level of the soil.

As you know, in the summer heat there is a significant increase in the temperature of pre-moistened soil. In this case, thermal energy is formed, which received the name "heat of wetting". This phenomenon is especially pronounced in areas with soil containing a large amount of mineral and organic components.

The so-called internal heat of the planet can contribute to a slight increase in temperature. In addition, there is such a thing as latent heat. It is formed due to the processes of condensation, freezing and crystallization of water.

All soils can be conditionally divided into two groups - warm and cold. The value of the temperature parameter depends on a number of factors, the most significant of which are the composition of the soil, the amount of humus contained in it and the level of humidity. Moreover, the higher the last parameter, the lower the heat capacity of sandy soils and the higher those of clay and peat soils, which are considered cold.

Creating an optimal soil temperature is one of the main conditions for the successful cultivation of crops. The temperature regime in the soil can be either positive (in this case, more thermal energy is stored in the soil than is released) or negative (more thermal energy is released than is retained). Currently, methods have been developed for daily, seasonal, annual, and even long-term regulation of soil temperature. Among such methods, not only hydroreclamation methods are known, but also agrotechnical, forestry and agroreclamation methods.

Growing plants in a particular area contributes to the effective regulation of the temperature regime of the soil cover. At the same time, a decrease in the annual heat turnover is observed. The creation of an air-thermal environment favorable for crops is possible, for example, by placing sowing plots near water bodies or on ridges and ridges, where the temperature is usually higher than in the lowlands.

Thermal conductivity

Another important characteristic of soils is their thermal conductivity. This term refers to the ability of the soil to conduct thermal energy.

It has been observed that dry soil has a lower thermal conductivity than moist soil. This phenomenon can be explained by significant thermal contact between the particles of the soil clod separated by a water film.

Fertility

Fertility is the ability of the soil to supply plants with the nutrients necessary for their normal growth and development, as well as water, heat and air. This quality is directly related to the nature of the process of soil formation.

Soil fertility indicators are determined by a number of natural and socio-economic factors. Indeed, the yield depends not only on the conditions of the natural environment, but also on the ongoing reclamation and agrotechnical measures. It is known, for example, that the difference in yields on fertile and infertile soils can be minimized if organic and mineral fertilizers are regularly applied to poor soils. However, it should be noted that the result increases not only due to an increase in the level of soil fertility due to top dressing. The fact is that fertility can be correlated with a complex system consisting of several components. In this case, these are the structure and composition of the soil, its physical, chemical and biological qualities. The degree of fertility is also determined by measures that regulate the content of microelements, nitrogenous and ash substances in the soil, and also allow optimizing air, temperature and water regimes.

Scientists claim that all soils are potentially fertile. The factors influencing the level of latent fertility include the presence of certain nutrients in the soil, their quantity and the water, air, chemical, physical and biological conditions formed in a given period of time. To increase crop yields and fertility levels, it is necessary to take into account and improve the parameters of all the above soil characteristics.

The value of potential soil fertility is formed in the process of soil formation and is an expression of its state at a particular point in time. However, it should be noted that not in all cases the quality of fertility increases simultaneously with the processes of natural and artificial cultivation. To achieve the expected result, when carrying out agrotechnical measures, it is necessary to take into account, analyze and predict the growth dynamics of potential fertility indicators. This will activate the hidden possibilities of the soil during development.

Soil fertility is one of the non-constant values ​​that change along with the transformation of conditions. Its indicators depend on the methods of using the soil horizon, air, water and temperature regimes, the characteristics of cultivated plants, the composition of fertilizers used for enrichment, etc.

Moreover, fertility is a characteristic of the soil, which does not belong to the category of inexhaustible resources. If used incorrectly, the soil is quickly depleted. To prevent this, it is important to carry out special events for its enrichment in a timely manner. In preparing the article, the following literature was used: Khvorostukhina S.A. How to improve soil fertility.

Introduction………………………………………………………..…………………3

1. Soil……………………………………………………………………………4

2. Soil types…………………………………………………………………………5

3. The composition and properties of the soil………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

4. General physical properties of the soil…………………………………………….11

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4.2 Thermal properties of soils……………………………………………………….16

4.3 Physical and mechanical properties…………………………………………….18

4.4 Air properties of soils…………………………………………………..20

5. Humus content………………………………………………………………….....22

6. Soil fertility………………………………………………………………..23

7. Types of soil fertility…………………………………………………..…...25

8. Factors limiting soil fertility………………………………26

9. Reproduction of soil fertility…………………………………………28

Conclusion………………………………………………………..……………..32

List of used literature……………………………………………..34

List of accepted terms………………………..…………………………..35

Introduction

The first scientific definition of soil was given by V.V. Dokuchaev: “The soil should be called the “daytime” or outer horizons of rocks (anything of which), naturally altered by the combined action of water, air and various kinds of organisms, living and dead.” He found that all soils on the earth's surface are formed by "an extremely complex interaction of the local climate, vegetation and animal organisms, the composition and structure of the parent rocks, the terrain, and, finally, the age of the country." These ideas of V.V. Dokuchaev were further developed in the concept of soil as a biomineral (“bio-inert”) dynamic system that is in constant material and energy interaction with the environment and is partially closed through the biological cycle.

The development of the theory of soil fertility is associated with the name of V.R. Williams. He studied in detail the formation and development of soil fertility in the course of natural soil formation, considered the conditions for the manifestation of fertility depending on a number of soil properties, and also formulated the main provisions on the general principles of increasing soil fertility when used in agricultural production.

Purpose: To study the general physical properties of the soil and their role in soil fertility

1.Show the importance of soil for plants and living organisms

2. Highlight the main property of the soil - fertility

3. Raise a caring attitude towards nature in general

4. Get acquainted with the process of soil formation

5.Studying the types of soil fertility

6. To study the role of humus for soil fertility

The soil

Soil is the most superficial layer of land on the globe, resulting from changes in rocks under the influence of living and dead organisms (vegetation, animals, microorganisms), solar heat and precipitation. The soil is a very special natural formation, having only its inherent structure, composition and properties. The most important property of the soil is its fertility, i.e. ability to ensure the growth and development of plants. In order to be fertile, the soil must have a sufficient amount of nutrients and a supply of water necessary for plant nutrition, it is precisely in its fertility that the soil, as a natural body, differs from all other natural bodies (for example, a barren stone), which are not able to meet the needs of plants in the simultaneous and the joint presence of two factors of their existence - water and minerals.

Soil is the most important component of all terrestrial biocenoses and the biosphere of the Earth as a whole; through the soil cover of the Earth there are numerous ecological connections of all organisms living on earth and in the earth (including humans) with the lithosphere, hydrosphere and atmosphere.

The role of the soil in the human economy is enormous. The study of soils is necessary not only for agricultural purposes, but also for the development of forestry, engineering and construction. Knowledge of soil properties is necessary to solve a number of health problems, exploration and mining, organization of green areas in urban areas, environmental monitoring, etc.

Soil types

Podzolic soil It is formed under the canopy of a coniferous forest, on which there is little grassy vegetation. There is a small supply of humus in the soil (0.7 - 1.5%). At the top layer (humus), the thickness is from 2 to 15 cm. Deeper, structureless, podzolic, whitish, infertile layer, whose thickness is from 2 to 30 cm.

Soddy-podzolic soil. It is more fertile.

This soil has a humus layer of 15 - 18 cm, under which there is another layer of infertile. Humus contains 1.5 - 1.8%. It has a dusty and easily destroyed lumpy structure. The solution soil is acidic.

Peat (marsh) soil. Formed on waterlogged soil. Peat soils have two types: upland and lowland, which differ greatly from each other. Raised peatlands are formed in elevated areas that are waterlogged by soft groundwater and atmospheric precipitation. Ledum, cranberry, blueberry, moss grow on it.

floodplain soils. They are located near rivers and are considered the best for vegetable growing. They contain a small amount of humus, but have a powerful humus capability and a strong granular structure. Its disadvantage is that cold air stagnates in lower areas, which is especially harmful in the spring. The floodplain soil has different acidity. According to their composition, the soil is divided into clay, loamy, sandy and sandy loam.

clay soil consists of clay, small particles, the permeability of air and water is very poor. After rains, rapid compaction occurs, by the formation of a crust on the surface.

loamy soil consists of large sand and small clay particles. Such soil is more fertile than clay soil, it retains moisture accumulated in winter and spring well. In years with insufficient rainfall, it suffers less from drought.

sandy soil is made up of larger particles. It leaches out nutrients quickly. Such soil easily passes water. Sandy soil has low fertility, but dries up and warms up quickly in spring. Planting and sowing is carried out at great depths.

sandy soil consists mainly of large particles, the content of clay substances is about 20%. Compared to sandy soil, water retention is slightly better in such soil. A distinctive feature is low fertility. In sandy loamy soil, humus accumulates little and the process of decomposition of organic matter proceeds rapidly.

The composition and properties of the soil

Soil is the surface layer of the earth's crust, which is formed and develops as a result of interactions, living microorganisms, rocks and is an independent ecosystem.

The most important property of the soil is soil fertility, i.e. ability to ensure the growth and development of plants. This property is of exceptional value for human life and other organisms. The soil is an integral part of the biosphere and energy in nature and maintains the gas composition of the atmosphere.

The soil consists of solid, liquid, gaseous and living parts. Their ratio varies not only in different soils, but in different horizons of the same soil. Naturally, the content of organic matter and living organisms decreases from the upper horizons of the soil to the lower ones and the intensity of the transformation of the components of the parent rock increases from the lower horizons to the upper ones. Minerals predominate in the solid part. Primary minerals (quartz, feldspars, hornblende, micas, etc.) form large fractions instead of rock fragments; secondary minerals (hydromica, montmorillonite, kaolinite, etc.) formed during weathering are thinner. The friability of soil composition is determined by the composition of its solid part, which includes particles of different sizes (from soil colloids, measured in hundredths of microns, to fragments with a diameter of several tens of cm). The bulk of the soil is usually fine earth - particles less than 1 mm

Solid particles in natural occurrence are not filled with the entire volume of the soil mass, but only some of it; the other part is made up of pores - gaps of various sizes and shapes between particles and their aggregates. The total pore volume is called soil porosity. For most mineral soils, this value varies from 40 to 60%. In organogenic (peat) soils, it increases to 90%, in waterlogged, gleyed, mineral soils it decreases to 27%. The water composition of the soil (water permeability, water-lifting capacity, moisture capacity) and soil density depend on porosity. The pores contain soil solution and soil air. The ratio of their continuity changes due to the entry into the soil of the atmosphere of precipitation, sometimes irrigation and groundwater, as well as moisture consumption - soil runoff, evaporation (suction by plant roots), etc.

The pore space freed from water is filled with air. These phenomena determine the air and soil regime of the soil. The more the pores are filled with moisture, the more difficult the gas exchange (especially O2 and CO2) between the soil and the atmosphere, the slower the oxidation processes in the soil mass and the faster the recovery processes. Soil microorganisms also live in the pores. The soil density (or bulk density) in the undisturbed composition is determined by the porosity and the average density of the solid phase. The density of mineral soils is from 1 to 1.6 g / cm 3, less often 1.8 g / cm 3, marshy gleyed soils - up to 2 g / cm 3, peat - 0.1-0.2 g / cm 2.

Dispersion is associated with a large total surface of solid particles: 3-5 m 2 /g for sandy soils, 30-150 m 2 /g for sandy soils, up to 300-400 m 2 /g for clay soils. Due to this, soil particles, especially colloidal and silty fractions, have surface energy, which manifests itself in the absorption capacity of the soil and the buffering capacity of the soil.

The mineral composition of the solid part of the soil largely determines its fertility. There are few organic particles (plant residues), and only peat soils are almost entirely composed of them. The composition of mineral substances includes: Si, Al, Fe, K, N, Mg, Ca, P, S; trace elements are significantly less: Сu, Mo, I, B, F, Pb, etc. The vast majority of elements are in oxidized form. Many soils, mainly in the soils of insufficiently moistened territories, contain a significant amount of CaCO3 (especially if the soils were formed on a carbonate rock), in the soils of arid regions - CaSO4 and other more easily soluble salts; soils of humid tropical regions are enriched with Fe and Al. One reaction of these general regularities depends on the composition of parent rocks, the age of the soil, the features of the relief, the climate, and so on. For example, on the main igneous rocks, soils richer in Al, Fe, alkaline earth and alkali metals are formed, and on rocks of acidic composition - Si. In the humid tropics, on the young weathering crust, soils are much poorer in iron and aluminum oxides than on older ones, and are similar in content to the soil of temperate latitudes. On steep slopes, where erosion processes are very active, the composition of the solid part of the soil differs slightly from the composition of parent rocks. Salt soils contain a lot of chlorides and sulfates (rarely nitrates and bicarbonates) of calcium and magnesium, which is associated with the initial salinity of the parent rock, with the entry of these salts from groundwater or as a result of soil formation.

The composition of the solid part of the soil includes organic matter, the main (80 - 90%) part of which is represented by a complex set of humic substances, or humus. Organic matter also consists of compounds of plant, animal and microbial origin, containing cellulose, lignin, proteins, sugars, resins, fats, tannins, etc. and intermediate products of their decomposition. When organic matter decomposes in the soil, the nitrogen contained in them is converted into forms available to plants. Under natural conditions, they are the main source of nitrogen nutrition for plant organisms. Many organic substances are involved in the creation of organo-mineral structural units (lumps). The emerging theoretical structure of the soil largely determines its physical properties, as well as water, air and thermal regimes. Organo-mineral compounds are represented by salts, clay-humus complexes, complex and intra-complex (chelates) compounds of humic acids with a number of elements (including Al and Fe). It is in these forms that the latter move into the soil.

The liquid part, i.e. soil solution - an active component of the soil that carries out the transfer of substances inside it, the removal from the soil and the supply of plants with water and dissolved nutrients. Usually contains ions, molecules, colloids and larger particles, sometimes turning into a suspension.

The gas part or soil air fills the pores not occupied by water. The amount and composition of soil air, which includes N2, O2, CO2, volatile organic compounds, etc., is constant and determined by the nature of many chemical and biochemical processes occurring in the soil. For example, the amount of CO2 in the soil air varies significantly in the annual and daily cycles due to the different intensity of gas release by microorganisms and plant roots. Gas exchange between the soil air and the atmosphere occurs mainly as a result of the diffusion of CO2 from the soil into the atmosphere and O2 in the opposite direction.

The living part of the soil consists of soil microorganisms (bacteria, fungi, actinomycetes, algae, etc.) and representations of many groups of invertebrate animals - protozoa, worms, mollusks, insects and their burrowing vertebrates, etc. The active role of living organisms in the formation of the soil determines its belonging to bioinert natural bodies - the most important components of the biosphere.

Soil chemistry affects human health through water, plants and animals. The lack or excess of certain chemical elements in the soil can be so great that it leads to metabolic disorders, causes or contributes to the development of serious diseases. So, a widespread disease endemic (local) goiter is associated with a lack of iodine in the soil. A small amount of calcium with an excess of strontium causes Urov's disease. A lack of fluoride leads to dental caries. With a high content of fluorine (over 1.2 mg/l), diseases of the skeletal system (fluorosis) often occur.

The soil is a complex natural system where, under the influence of living organisms and other factors, the formation and destruction of complex organic compounds occur. Mineral substances are extracted by plants from the soil, are part of their own organic compounds, then are included in the organic matter of the body, first of herbivorous, then of insectivorous, carnivorous animals. After the death of plants and animals, their organic compounds enter the soil. Under the influence of microorganisms, as a result of complex multi-stage decomposition processes, these compounds are converted into forms available for absorption by plants. They are partly part of organic matter, retained in the soil or removed with filtered and waste water. As a result, there is a regular circulation of chemical elements in the system "soil - plants - (animals - microorganisms) - soil". This cycle of V.R. Williams called small, or biological. Due to the small circulation of substances in the soil, fertility is constantly maintained. In artificial agrocenoses, such a cycle is disrupted, since a person withdraws a significant part of agricultural products, using it for their own needs. Due to the non-participation of this part of the production in the cycle, the soil becomes infertile. To avoid this and increase soil fertility in artificial agrocenoses, a person makes organic and mineral fertilizers. Applying the necessary crop rotations, carefully cultivating and fertilizing the soil, a person increases its fertility so significantly that most modern cultivated soils should be considered artificial, created with the participation of man. Thus, in some cases, human impact on soils leads to an increase in their fertility, in others - to deterioration, degradation and death.

General physical properties of the soil.

Among physical soil properties distinguish its general physical, physico-mechanical, water, air and thermal properties. Physical properties affect the nature of the soil-forming process, soil fertility and plant development.

General physical properties include soil density, solids density and porosity.

Soil density is the mass per unit volume of absolutely dry soil, taken in natural composition, expressed in grams per cubic centimeter. Soil density, g / cm 3, is calculated by the formula

d v = m/V .

Where m- mass of absolutely dry soil, g; V- the volume occupied by the soil sample, cm 3 .

Soil density depends on the granulometric and mineralogical composition, structure, humus content and tillage. After processing, the soil is initially loose, and then gradually compacted, and after a while its density changes little until the next processing. The upper humus and structured horizons have the lowest density. For most crops, the optimal soil density is 1.0 ... 1.2 g / cm 3.

The density of the solid phase of the soil is the mass of dry soil per unit volume of the solid phase of the soil without pores. It is calculated, g / cm 3, according to the formula

d = m/Vs.

Where m- mass of dry soil, g; Vs- volume, cm 3 .

In low-humus soils and in the lower mineral horizons, the density of the solid phase is 2.6...2.8 g/cm 3 . With an increase in the humus content, the density of the solid phase decreases to 2.4...2.5 g/cm 3 , and in peat soils - to 1.4...1.8 g/cm 3 . The density of the solid phase is used to calculate the porosity of the soil.

Moisture absorption, air exchange in the soil, the vital activity of microorganisms and the development of plant root systems depend on the density of the soil.

The porosity (duty cycle) of the soil is the total volume of all pores between the particles of the solid phase of the soil. Porosity (total) is calculated from the density of the soil and the density of the solid phase and is expressed as a percentage of the total soil volume:

P total =(1-dv/d)100

Where d v- soil density, g/cm 3 ; d- density of the solid phase of the soil, g/cm 3 .

Porosity depends on the granulometric composition, structure, content of organic matter. In arable soils, porosity is due to cultivation and cultivation techniques. With any loosening of the soil, porosity increases, and with compaction it decreases. The more structural the soil, the greater the overall porosity.

The sizes of the pores, which together form the total porosity of the soil, vary from the thinnest capillaries to larger gaps that do not have capillary properties. Therefore, along with the general porosity, capillary and non-capillary porosity of the soil is also distinguished. Capillary porosity is characteristic of undisturbed loamy soils, while non-capillary porosity is characteristic of structural and loose soils.

The pores can be filled with water or air. Capillary pores provide the water-holding capacity of the soil, the supply of moisture available to plants depends on them. Non-capillary pores increase water permeability and air exchange. A stable supply of moisture in the soil with simultaneous good air exchange is created when non-capillary porosity is 55 ... 65% of the total porosity. Depending on the total porosity during the growing season for loamy and clayey soils, a qualitative assessment of soil porosity is given. The following is a qualitative assessment of soil porosity according to N. A. Kachinsky.

Soil porosity ensures the movement of water in the soil, water permeability and water-lifting capacity, moisture capacity and air capacity. According to the general porosity, one can judge the degree of compaction of the arable soil layer. Soil fertility largely depends on porosity.

4.1 Water properties of soils. The most important water properties of soils include water permeability, water-lifting capacity, soil moisture capacity.

Water permeability is the ability of soil to absorb and pass water through it. The process of permeability involves the absorption of moisture and its filtration. Absorption occurs when water enters the soil that is not saturated with water, and filtration begins when most of the pores of the soil are filled with water. In the first period of water entering the soil, the water permeability is high, then it gradually decreases and by the time of complete saturation (by the beginning of filtration) it becomes almost constant. Water absorption is due to sorption and capillary forces, filtration - due to gravity.

The degree of use of water resources depends on water permeability. With low water permeability, part of the atmospheric precipitation or irrigation water flows over the surface, which leads not only to unproductive waste of moisture, but can also cause soil erosion. Soils are considered to be well permeable, in which water penetrates to a depth of up to 15 cm during the first hour. In medium permeable soils, water passes from 5 to 15 cm in the first hour, and up to 5 cm in poorly permeable soils. The highest water permeability is characteristic of sandy, also well structured soils. soils, low - for clayey and structureless dense soils. Water permeability also depends on the composition of absorbed cations: sodium reduces water permeability, while calcium, on the contrary, increases it.

Water-lifting capacity - the property of the soil to lift water through the capillaries. Water in soil capillaries forms a concave meniscus, on the surface of which surface tension is created. The thinner the capillary, the more concave the meniscus and, accordingly, the higher the water-lifting capacity. Loamy soils (3...6 m) have the highest capillary rise. In sandy soils, the pores are large, so the height of the capillary rise is 3...5 times less than in loamy soils, and usually does not exceed 0.5...0.7 m. In dense clay soils, this indicator decreases due to the fact that that very fine pores are filled with bound water.

The rate of capillary rise depends on the size of the capillaries and the viscosity of the water, determined by its temperature. In large pores, water rises faster, but reaches a small height. With a decrease in the radius of the capillaries, the speed decreases, and the lift height increases. As the temperature rises, the viscosity of water decreases, so the rate of its capillary rise increases. Salts dissolved in water have a significant effect on the rate of capillary rise. Mineralized groundwater, unlike fresh water, rises to the surface through capillaries at a faster rate. Salinized groundwater during their capillary rise often leads to soil salinization.

Water holding capacity is the ability of soil to hold water. Depending on the water-retaining forces, there are maximum adsorption, capillary, field-limiting and total moisture capacities.

The maximum adsorption capacity (MAV) is the largest amount of moisture inaccessible to plants, which is firmly held by the molecular forces of the soil (adsorption). It depends on the total surface of the particles, as well as on the content of humus: the more clay particles and humus in the soil, the higher the maximum adsorption capacity.

Capillary capacity (KB) - the amount of water that is retained in the soil when the capillary pores above the groundwater level are filled. Capillary moisture capacity depends on the height above the groundwater table. It is greatest near groundwater, and decreases as it rises to the surface.

Maximum field moisture capacity (MPC) - the amount of water that is retained in the field after complete wetting of the soil from the surface and free runoff of excess water. Groundwater in this case does not affect soil moisture. The maximum field capacity depends on the granulometric composition, density and porosity of the soil. It corresponds to the amount of capillary-suspended water. A synonym for the limiting field moisture capacity is the smallest moisture capacity (HB).

Total moisture capacity (PV) is the state of soil moisture when all the pores are filled with water. Full moisture capacity is observed above water-resistant horizons, on which groundwater is located. In conditions of complete saturation of the soil with water, there is no aeration, which makes it difficult for the roots of plants to breathe.

Soil moisture is divided into absolute and relative.

Absolute moisture is the total amount of water in the soil, expressed as a percentage of the mass of the soil.

Relative humidity - the ratio of the absolute moisture content of a given soil to its maximum field capacity.

The availability of soil moisture to cultivated plants is determined by relative and absolute soil moisture.

Plant wilting moisture - soil moisture at which plants show signs of wilting that do not disappear when plants are placed in an atmosphere saturated with water vapor, that is, this is the lower limit of moisture availability for plants. Knowing the absolute humidity and the wilting point of plants, it is possible to calculate the reserve of productive moisture.

Productive (active) moisture - the amount of water in excess of wilting moisture, used by plants to create a crop. So, if the absolute moisture content of a given soil in the arable layer is 43%, and the wilting moisture content is 13%, then the reserve of productive moisture is 30%.

For ease of determination, the amount of productive moisture is expressed in millimeters of water column. In this form, productive moisture is easier to compare with the amount of precipitation. Each millimeter of water on an area of ​​1 ha corresponds to 10 tons of water.

4.2 Thermal properties of soils. The main thermal properties of the soil include heat absorption capacity, heat capacity and thermal conductivity.

Heat absorption capacity - the property of the soil to absorb the radiant energy of the sun. The heat-absorbing capacity index is related to the albedo value.

Albedo is the ratio of the reflected radiation to the total radiation reaching the Earth, expressed as a percentage. The lower the albedo, the more the soil absorbs solar radiation. This indicator depends on the color of the soil, moisture, structure, humus content and granulometric composition. Highly humus soils are dark in color, so they absorb 10 ... 15% more radiant energy than low humus soils. Compared to sandy soils, clay soils are characterized by a high heat absorption capacity. Dry soils reflect radiant energy by 5...11% more than wet soils.

Heat capacity - the ability of the soil to retain heat. Distinguish between specific and volumetric heat capacity of soil.

Specific heat capacity - the amount of heat required to heat 1 g of dry soil by 1 ° C (J / g per 1 ° C).

Volumetric heat capacity - the amount of heat expended to heat 1 cm 3 of dry soil by 1 ° C (J / cm 3 per 1 ° C).

The heat capacity of the soil depends on the mineralogical and granulometric composition, as well as on the content of water and organic matter in it.

For dry soils, a small range of fluctuations in heat capacity is 0.170 ... 0.200. When moistened, the heat capacity of sandy soils increases to 0.700, clayey - 0.824, peaty - up to 0.900. Sandy and sandy loamy soils are less moisture-intensive, therefore they warm up faster and are called "warm". Clay soils contain more water, which requires a lot of heat to heat up, which is why they are called "cold".

Thermal conductivity - the ability of the soil to conduct heat. It is measured by the amount of heat in joules that passes through 1 cm 3 of soil in 1 s. The thermal conductivity of the main parts of the soil varies greatly. So, the thermal conductivity of quartz is 0.00984; granite - 0.03362; water - 0.00557; air - 0.00025 J cm 3 / s.

Since heat in the soil is transferred mainly through solid particles, water and air, as well as when the particles come into contact with each other, the thermal conductivity largely depends on the mineralogical and granulometric composition, humidity, air content and soil density. The larger the mechanical elements, the greater the thermal conductivity. Thus, the thermal conductivity of coarse-grained sand with the same porosity and moisture content is twice as high as that of the coarse-grained fraction. In terms of thermal conductivity, the solid phase of the soil is about 100 times higher than air, therefore loose soil has a lower thermal conductivity coefficient than dense soil.

4.3 Physical and mechanical properties. The most important physical and mechanical properties of the soil include plasticity, stickiness, swelling, shrinkage, cohesion, hardness and resistivity (resistance during processing). The conditions of soil cultivation, the work of sowing and harvesting units depend on these properties.

The plasticity and stickiness of the soil are due to the presence of clay particles and water in it.

Plasticity is the ability of a soil to change its shape under the influence of a force without disturbing the structure and to retain it after the removal of this force. The more clay particles in the soil, the more pronounced its plasticity. The greatest plasticity is characteristic of clay soils. Sandy soils have no plasticity. Plasticity also depends on the composition of the absorbed cations and the content of humus. So, with a significant content of absorbed sodium cations in the soil, its plasticity increases, and when saturated with calcium, it decreases. With an increase in the humus content, the plasticity of the soil decreases.
Stickiness is directly related to plasticity and is also due to the presence of clay particles and water in the soil. Dry soils are not sticky. As we moisten up to about 80% of the lowest moisture capacity, the stickiness increases, and then begins to decrease.

Stickiness is determined by the force required to lift a metal plate from the soil, and is expressed in grams per square centimeter. By stickiness, soils are divided into extremely viscous (> 15 g / cm 2), highly viscous (5 ... 15), medium viscous (2 ... 5) and slightly viscous (<2г/см 2). Наибольшую липкость имеют глинистые почвы, наименьшую - песчаные. Почвы высокогуму-сированные и структурные не имеют липкости даже при увлажнении до 30...35 %. С липкостью связана физическая спелость почвы, то есть состояние влажности, при котором почва хорошо крошится на комки, не прилипая к орудиям обработки. Весной в первую очередь поспевают к обработке песчаные и супесчаные почвы, а при одинаковом гранулометрическом составе - более гумусированные.

Swelling is the increase in soil volume when wet. Clayey soils with a high content of colloids, on the surface of which moisture is sorbed, swell the most. Sandy soils with very low colloid content do not swell at all. Exchangeable sodium cations greatly increase the swelling of soils, so solonetzes are characterized by high swelling. With significant swelling, the soil structure is destroyed.

Shrinkage is the reverse process of swelling. When the soil dries, cracks form, the roots of plants are torn, and moisture loss due to evaporation increases. The greater the swelling of the soil, the greater its shrinkage.

Cohesion is the ability of a soil to resist an external force that tends to pull soil particles apart. Connectivity is expressed in grams per square centimeter. Clay unstructured soils have the highest connectivity in the dry state, and sandy soils have the lowest. When structuring clay and loamy soils, their coherence sharply decreases.

Hardness - the ability of soil to resist compression and wedging. Hardness and cohesion depend on particle size distribution, humus content, composition of exchange cations, structure and degree of moisture. Soils with a high content of humus, saturated with calcium and having a good cloddy-granular structure, do not have high hardness and cohesion. Their processing requires less energy.

Resistivity is the force that is expended on cutting the layer, its turnover and friction on the working surface of the plow. It is characterized by soil resistance in kilograms per 1 cm 2 of the cross section of the soil layer raised by the plow. The resistivity depends on the physical and mechanical properties of the soil and ranges from 0.2...1.2 kg/cm 2 .

To improve the physical and physical-mechanical properties of the soil, a set of measures is used: the application of organic fertilizers, the cultivation of perennial grasses, the sowing of green manure, the choice of terms and methods of tillage, depending on the state of its moisture content. When liming acidic soils and gypsuming alkaline soils, the composition of absorbed cations changes and the physical and mechanical properties improve. This is also facilitated by measures that reduce soil compaction by machines (minimization of tillage, deep loosening, etc.).

4.4 Air properties of soils. Soil is a porous body in which air is almost constantly present in various quantities. It usually consists of a mixture of gases and fills the water-free pores of the soil. The sources of soil air are atmospheric air and gases formed in the soil itself.

Most plants cannot exist without a constant supply of oxygen to the roots and removal of carbon dioxide from the soil - there must be a constant exchange with atmospheric air. The exchange of soil air with atmospheric air is called gas exchange or aeration.

With a lack of oxygen and an excess of carbon dioxide in the soil air, the development of plants is inhibited, the absorption of nutrients and water is reduced, and root growth slows down. Lack of oxygen leads to the death of plants. All this necessitates constant soil aeration. Soil air can be in various states - free, adsorbed by the surface of soil particles and dissolved in the liquid phase of the soil. Free soil air is of great importance in soil aeration. It is usually located in non-capillary and capillary pores, has mobility and can be exchanged with atmospheric air.

The composition of soil air differs from that of the atmosphere in that it contains less oxygen and more carbon dioxide.

In addition to the three main gases (N2, O2, CO2), soil air contains small amounts of CH4, H2, etc.

During the growing season, the composition of soil air is constantly changing as a result of the activity of microorganisms, plant respiration and gas exchange with the atmosphere. In arable, well-aerated soils with favorable physical properties, the CO2 content in the soil air during the growing season does not exceed 1–2%, and the O2 content does not fall below 18%.

The main factors affecting gas exchange are diffusion, changes in soil temperature, barometric pressure, soil moisture, and wind. All these factors act together in natural conditions, but diffusion must be considered the main one. As a result, gases move in accordance with their partial pressure.

The state of gas exchange is determined by the air properties of soils. They include breathability And air capacity.

With the advent of spring, earthworks begin. I come to my grandmother's village and help her plant potatoes and seedlings. In rural areas, all people are engaged in agriculture. This is their lifestyle. Soils are formed in different climates, under different vegetation and therefore have different fertility.. In my area there is black soil, and these are the most fertile lands.

Fertility is the main feature of the soil

Every day we walk the earth. She surrounds us everywhere. The soil feeds us! Have you ever wondered why it is possible to grow vegetation in the soil? And the answer is very simple. Next, I will just talk about this feature of the soil.

Soil is the top layer of the earth's crust. It has its own feature - it is fertility. And all because in the soil there is humus (humus). This is the upper fertile organic layer, which is formed as a result of the death and decay of the plant world and animals. The more humus, the more fertility. It is measured on a 10-point scale - this is called bonitet. Thanks to this property, we have such vital food.

Our soil is unique. It has many basic and additional properties:

• grading- this is the ratio in the composition of the soil of different mineral elements;
• duty cycle- this is the presence of pores (gaps) in the composition of the earth;
• humidity How much water does the earth contain?
• hardness;
  
• stickiness.

But we must know what Fertility is the main property of the soil..

How soil was formed

Soil is formed as a result Odecay and decomposition of organic matter (flora and fauna) and the action of inorganic nature (wind, water and temperature). It began to appear millions of years ago. This is a very complex geological and historical process. The main shells of the Earth and minerals began to form. Scientists say that after the appearance of water and air on Earth, the first unicellular and algae began to live. Volcanoes erupted, and then more complex living organisms appeared.

Living and non-living nature began to contact each other. As a result, such a necessary soil appeared for us..

When planting a particular crop, one should not ignore the main properties of the soil used, since the quality of the crop depends on its fertility. We are used to using a wide variety of fertilizers, but few people think about which components are missing in the composition of the soil. Of course, it will not work to determine this by eye, but it is simply necessary to know about the main characteristics of the substrate - we will analyze them further.

Basic soil properties

The soil is a whole system with its own rhythm of life and development rules, so it is not surprising that its properties can be very different. Let's consider the main ones.

Fertility

Under the fertility of the soil, it is customary to understand the whole set of its properties and the processes occurring inside that contribute to the normal growth and development of plants. A substrate is considered fertile if it contains a huge amount of nutritional components, among which it is especially worth highlighting nitrogen, potassium, magnesium, copper, phosphorus, sulfur and, of course, humus (in good soils it is up to 10%).

Did you know? Soil is the second largest carbon store behind the oceans.

Mechanical composition

The mechanical composition is another very important property that allows you to attribute the soil to a certain variety. By and large, this concept means the texture or granular composition of the substrate, formed from millions of different elementary particles.
This value is expressed as a percentage of the weight of completely dry soil. Features of the mechanical composition are based not only on the initial characteristics of the parent rock, but also on the parameters of the processes of soil formation that constantly occur inside.

Physical properties

The mechanical composition directly affects the physical properties of the soil, such as water permeability (or density), porosity, and moisture capacity. Meanwhile, all of them are also very important factors in choosing a site when planting cultivated plants. We will talk more about these characteristics and their relationship later.

What determines fertility and how to increase it

Of course, for any agrarian or a simple summer resident who grows various plants on his site, the first task will be to increase soil fertility, which should increase the amount of crops grown. Consider the main factors in maintaining the soil and how to achieve the desired result.

Fertility Support Factors

Fertility factors are understood as the totality of the amount of water, air, heat, zonal and nitrogen nutrition of plants that directly affect their growth and development. At the same time, the organization of suitable fertility conditions implies an integrated approach to the possibility of providing plants with the earthly growth factors they need.

• the amount of water in the soil;
• rainfall and irrigation (increased sodium accumulation can be detrimental to the crop being grown);
• the value of total evaporation of moisture, which will confirm the total increase in the volume of liquid throughout the year;
• adequate levels of nutrients.

Did you know? The process of soil formation is very slow. Thus, the formation of only 0.5–2 cm of its fertile layer takes almost a century.

Ways to increase fertility

The most important conditions on which fertility will depend are temperature, nutrient, water-air, biochemical, physico-chemical, salt and redox regimes.
A person can influence the features of some of them by taking the following measures:

1. By organizing a competent crop rotation by planting crops in the same place with a five-year interval. That is, whatever you grow, it is advisable to change the place where the crop grows every five years.
2. Sowing on the site the so-called "healer plants", among which garlic, wormwood, shepherd's purse, nettle stand out.
3. Attracting earthworms. It has long been established that with a large accumulation of them, the soil gives higher yields, which means that their presence is very desirable (California species are distinguished by increased digestibility of various organics).
4. Performing heat treatment to destroy all kinds of pests and weeds. The main disadvantage of this method is the impossibility of using it in large areas (more relevant for greenhouses and hotbeds).
5. By introducing organic matter into the soil, especially manure, ash and compost.
6. Carrying out a mixed planting of crops. Together with a cultivated plant, experts recommend planting a suitable "neighbor" that will scare away pests and prevent the substrate from depleting. For these purposes, you can plant basil, rosemary, chamomile, marigolds, which, among other things, will be very attractive to bees, thereby contributing to the pollination of plants and increasing crop volumes.
7. Organizing periodic rest for each separate section of the territory. With the constant, uninterrupted cultivation of the same crops, any soil gets tired, so during the selected year it is better not to plant anything at all, only weeding, mulching and fertilizing. With the advent of autumn, the site is dug up, trying to move the top layer down.
8. Sowing green manure plants, in which there is an increased content of protein, starch and nitrogen. In this case, oats, rye, mustard, sunflower will become ideal "inhabitants" of your site. Mostly they are sown after harvest, although in some cases they are grown at the same time as the main crops.

The mechanical composition and its effect on the soil

At the beginning of the article, we already mentioned such a soil characteristic as the mechanical composition, and now we invite you to understand in more detail its features and the distribution of soil into types in accordance with this criterion.

What is the mechanical composition

In the structure of the earth there are particles of very different sizes: both stones, the remains of rocks and mineral compounds (often reach 10-12 cm in diameter), and very small elements invisible to the naked eye. Moreover, you will not see some of them even with a conventional microscope, so when studying soil mixtures, you have to use a special electrical apparatus.
The properties of the substrate, its richness and fertility largely depend on the size of these components, and if we perform a mechanical analysis of the substrate, we can attribute it to a specific type: physical clay (particle sizes are approximately 0.01 mm), physical sand ( particles reach sizes from 0.01 to 1 mm), colloidal components (0.0001 mm in size). Let us consider the most typical types of soils identified on the basis of their mechanical composition.

Soil types depending on the composition

Even if you do not have special equipment, and it is impossible to determine the type of soil mixture by eye, the following diagnostic methods (dry and wet) will report on its approximate mechanical composition.

clayey

This substrate contains up to 50% pure clay and is characterized by such definitions as "raw", "viscous", "heavy", "sticky" and "cold". Clay soils allow water to pass through very slowly, retaining it on the surface, which makes it almost impossible to cultivate the site: wet clay sticks to gardening tools.
In a dry state, such soil is very difficult to grind with your fingers, but when you do succeed, you get the feeling that you have a homogeneous powder in your hands. When wet, it begins to smudge heavily, rolls perfectly into a lace and allows you to form a ring out of the soil without any problems.

sandy loam

Unlike the first option, dry sandy loamy soils are easily rubbed with fingers and in this state allow small grains of sand to be seen with the naked eye. If you wet the substrate and try to download it into a string, you get only a small part. In this case, along with clay, the substrate also contains sand, which is noticeably larger (20% to 80%).

Important! If the amount of sand in the soil mixture exceeds the specified value, then the quality of the soil as a whole will decrease.

Sandy

Such soils are formed exclusively by sandy grains, with a small addition of clay or silt particles. This type of substrate is structureless and is not characterized by binding properties.

loamy

When rubbing dry loams in the fingers, a fine powder with palpable grains of sand is obtained. After moistening, it can be rolled into a lace that breaks when trying to form a ring. Light loam will not allow you to form a ring, and the cord will crack when rolling. Heavy loamy substrates make it possible to obtain a ring with cracks. Loamy soils themselves are already rich in mineral compounds, and they are also characterized by a fairly high friability, do not prevent the passage of moisture into the lower layers and provide normal air circulation.

The influence of the composition on the future harvest

Less or more clay and sand in the soil will always affect the quality and quantity of the crop, so when choosing a site for planting seedlings of cultivated crops, it is important to take this nuance into account. On clay or completely sandy soils, most familiar garden plants will be rather uncomfortable, if they can take root there at all. Planting in loamy or sandy loamy soils can bring great results, but they will not be able to compare with chernozems fertilized with organic matter and mineral compositions.

Physical properties of the soil

The main physical properties of the soil, which you need to pay attention to first of all, are density and porosity, and it cannot be said that they do not affect each other in any way. The denser the soil, the less its porosity, which means that there is no need to talk about good water, air permeability or aeration. Let's take a closer look at this issue.

Density (bulk weight)

Soil density is the mass of a unit volume, calculated in grams per cubic centimeter, or an absolutely dry soil mixture in its natural composition. Density determines the relative position of all constituent particles, taking into account the free space between them, and also affects moisture absorption, gas exchange and, as a result, the development of the roots of cultivated crops.

If we consider the density of soil mixtures in their dry state, then the following degrees can be distinguished:

1. Merged or very dense addition, when the soil is practically not amenable to the influence of a shovel (it can enter the ground no more than 1 cm). Basically, this option is typical for confluent chernozem soils and columnar solonetzes.
2. A dense structure, in which the shovel enters the ground no more than 4-5 cm, and the substrate itself breaks with difficulty. It is typical for heavy, clayey and uncultivated soils.
3. Loose build - agricultural tool easily deepens into the ground, and the soil itself is well structured. These are sandy loam soils and upper, well-structured loam horizons.
4. Loose texture is characterized by high flowability of the soil, the individual particles of which are loosely connected to each other. This option is typical for sandy and structureless substrates.

Important! The specific type of density depends not only on the mechanical, but also on its chemical composition and humidity. This property of the soil has considerable practical value in agriculture, for the most part in terms of the possibility of its processing.

Porosity

Porosity is the exact opposite of the above density, and from a scientific point of view, this is the total volume of all free space (pores) between the solid constituents of the soil. It is expressed as a percentage of the total volume of the substrate, and for mineral varieties, the range of these values ​​will be in the range of 25–80%. In soil horizons, the pores do not always have the same shape and diameter, therefore, based on their size, capillary and non-capillary types of soil are distinguished. The first is equal to the volume of all capillary pores in the soil, and the second is equal to the volume of only large pores.
The sum of the two values ​​will be the total porosity. In many ways, this characteristic depends on the density, structure and mechanical composition, which we talked about earlier. In macrostructural substrates, pores will occupy more volume, in microstructural substrates - a smaller part of it. When a structureless substrate dries out, a soil crust forms on the surface of the earth, which adversely affects the growth and development of crops. Of course, it should be removed in a timely manner, and if possible, look for other, more successful places for planting.

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