The general physical properties of soil include relative density, bulk density and porosity.

Relative soil density is the ratio of the mass of its solid phase to the mass of water in the same volume at a temperature of +4° C.

The value of the relative density of soils depends on the density of the mineral particles included in it and their ratio, as well as on the amount of organic matter.

Typically, the density of mineral soil horizons ranges from 2.4 to 2.8, and of organic soil horizons from 1.4 to 1.8 (peat). The density of the upper humified soil horizons is on average 2.5-2.6, the lower - 2.6-2.7.

Bulk density of soil- the mass of a unit volume of absolutely dry soil, taken in its natural composition, expressed in g/cm3.

Bulk density is one of the most important properties that determines the ability of soil to pass and retain moisture, air, resist tillage tools, etc. Bulk density depends on the type of vegetation, mechanical and mineralogical composition of the soil (dispersity), composition, structure and degree of soil cultivation .

The lowest bulk density is usually observed in the upper soil horizons, the highest in illuvial and gley horizons. In well-structured, loose soddy-podzolic soils, the lowest volumetric density is observed in forest litter - 0.15-0.40 g/cm3, in humus horizons it increases to 0.8-1.0, in podzolic ones - up to 1.4- 1.45, illuvial - up to 1.5-1.6 and in the parent rock - up to 1.4-1.6 g/cm3.

The bulk density of soils depends on the type of vegetation. Thus, in humus horizons under closed spruce forests it is 0.9-1.1, under birch forests - 1.0-1.3, under cereals - 1.2-1.4 g/cm3.

The soil is considered loose , if the volumetric density of humus horizons is 0.9-0.95,

normal - 0,95-1,15,

compacted - 1.15-1.25 and

highly compacted - more than 1.25 g/cm3.

Porosity(porosity or porosity) - the total volume of all pores and spaces between particles of the solid phase of the soil.

It is calculated from the density and bulk density of the soil and is expressed as % of soil volume using the formula.

There are several forms of porosity, the most important of which are capillary and non-capillary .

Capillary Porosity is usually measured in a laboratory setting and is equal to the amount of water held by the thin capillary spaces between solid soil particles. Typically, the more clay particles, the greater the capillary porosity. In structured soils, water flows out between the lumps due to the large size of the pores, and in the lumps themselves is retained in capillaries.

The difference between total and capillary porosity is non-capillary porosity.

The highest porosity (80-90%) is observed in forest litter, grass felt, peat, i.e. organic horizons.

In mineral humus-rich horizons it is 55-65%, in the upper humus-free horizons it is 45-55%, in the lower soil horizons it can be below 45%.

The minimum porosity is observed in gley soil horizons and is about 30%.

For the development of root systems of tree species, the best conditions are created when soil porosity is 55-65%; with a porosity of 35-40%, roots penetrate the soil with difficulty, and with the porosity of gley horizons, it practically becomes root-impermeable.

Non-capillary porosity is of great importance. For the horizons most developed by roots, it is usually more than 10%; when it decreases to 3%, the lower soil horizons become inaccessible to roots. Non-capillary porosity allows air to penetrate into the soil-aeration. For normal plant development, it is important that soils have high capillary porosity and aeration porosity of at least 20% of the soil volume.

PHYSICAL AND MECHANICAL PROPERTIES OF SOIL

A number of processes occurring in soils are determined by their physical and mechanical properties, which manifest themselves under the influence of external loads and are divided into deformation, strength and rheological.

Deformation properties characterize the behavior of soils under loads that do not lead to their mechanical destruction. These include compressibility, subsidence, consolidation (compaction) .

Strength properties characterize the behavior of soils under loads that cause their destruction - shift, rupture .

Rheological properties characterize the behavior of soil under pressure over time. These include viscosity, plasticity, thixotropy .

The concept of “physical and mechanical properties” in soil science has a wider range of application than in mechanics, geology, and soil science.

Accordingly, physical and mechanical properties in soil science also include swelling, shrinkage, stickiness , i.e. the properties of highly dispersed systems, manifested without mechanical influences from the outside

The study of the physical and mechanical properties of soils is important not only from the standpoint of understanding the mechanisms of physical processes occurring in them, but is of great practical importance for agriculture. Physico-mechanical properties determine the conditions for soil cultivation, make it possible to obtain quantitative estimates of energy costs for their cultivation and select the optimal timing of field work, during which the soil is deformed to the least extent and cultivation is carried out with the lowest fuel costs

SOIL DEFORMATION PROPERTIES

Soil compressibility under load occurs during their mechanical processing. The need to study this issue is especially acute at the present time, when heavy agricultural machinery is used in the fields and active compaction of surface soil horizons occurs.

The compressibility of soils is determined by their mineralogical and granulometric composition, the nature of porosity and fracturing, soil structure and structural strength, the composition and orientation of clay particles, their size and shape, soil moisture and hydrophilicity of the colloidal fraction

High initial porosity of soils serves as an indicator of the possibility of sufficiently large soil compaction when processing it with heavy equipment

Soil compressibility leads to a decrease in overall porosity, changes in the size and shape of pores, the size and shape of structural units

Compressibility is characterized by the compaction coefficient

Soil compressibility is not a completely reversible deformation. Under repeated loads, the compression curve takes the form of a loop, which is caused by the destruction of structural bonds and the accumulation of residual deformation.

The maximum residual deformation will correspond to the characteristics of the physical and chemical properties of specific soils and makes it possible to predict the minimum porosity under various treatments in real conditions, i.e., their maximum possible compaction.

A special case of the manifestation of soil compressibility is subsidence.

Drawdown is called a decrease in the surface of soils as a result of a decrease in their porosity and the dissolution of the salts they contain during soaking.

This phenomenon is associated with such relief forms as steppe saucers and pods. Subsidence on loess soils is especially significant when they are introduced into irrigated agriculture, which is explained by the high porosity of the rocks, low hydrophilicity, and the removal of easily soluble salts, which are “adhesive” substances for their structure.

Subsidence soils and soils can in some cases create significant irrigation diversity of microrelief on irrigated areas, which causes redistribution of irrigation water on the surface of the field, creates a mosaic of moisture and can lead to the formation of complexity of the soil cover.

All this complicates soil cultivation and agricultural exploitation of irrigated areas, creates a diversity of crops, and reduces the efficiency of irrigation.

STRENGTH PROPERTIES

Shift = Connectivity characterizes the ability of the soil to resist the breaking force tending to separate the mechanical elements, i.e., it determines the property of mutual adhesion of soil particles.

It is expressed in kg/cm2.

Cohesion must be taken into account when assessing important soil performance characteristics such as resistivity, adhesion. This indicator characterizes the strength of the structure, which is also important to know when assessing the reclamation characteristics of soils.

Cohesion depends on the granulometric and mineralogical composition of soils, the amount and composition of adhesive components, exchangeable bases, organic matter content, and moisture content.

Soil structuring, by increasing the strength of individual aggregates, generally reduces soil cohesion, facilitates their cultivation, and optimizes the development of root systems.

The water content of soils has the greatest influence on soil cohesion.

The influence of organic matter on soil cohesion is twofold.

Humus increases the cohesion of sandy soils and reduces it in clayey soils by increasing their aggregation and reducing the contact area.

The most cohesive are clays, low-structured soils saturated with monovalent cations. In light soils, organic matter and some moisture increase cohesion; in loamy soils, on the contrary, they decrease it.

Soil cohesion affects the quality of processing and resistance to the impact of machines and implements.

Soil hardness is closely related to the adhesion strength of soil particles.

Hardness is the property of soil in its natural occurrence to resist compression and wedging. Hardness is measured using hardness testers and expressed in kg/cm2. At the same density, the hardness of non-swelling soils can vary significantly depending on moisture content. Soil hardness is determined by the same characteristics as cohesion (mineralogy, dispersion, presence of electrolytes, composition of exchangeable bases, humus content, moisture).

It is assessed already during the field description. In this case, the following gradations are distinguished: loose, loose, compacted, hard, very hard soil.

Soil hardness varies over a very wide range: from 5 to 60 kg/cm2 and higher. The greatest hardness in the dry state is characterized by drained soils and solonetzes.

Assessing the hardness of genetic horizons as the hardest, we can distinguish solonetzic, confluent, illuvial horizons, plow base, and soil crusts.

The hardness of the soil determines the traction force of agricultural implements. The traction force per unit working area of ​​the processing tool is called specific resistance.

With a decrease in humidity, the hardness of soils sharply increases, their resistivity increases, and the energy costs for cultivation increase. With an increase in humidity, the stickiness of soils increases, the adhesion force of soil particles to the surface of processing tools increases, which also leads to an increase in resistivity.

With increased humidity, soil crumbling and the formation of agronomically valuable aggregates do not occur, and soils become buried. Tilling dry soils disperses the soil, which reduces their erosion resistance and significantly worsens surface properties.

The resistivity of soils under natural conditions ranges from 0.2 to 1.2 kg/cm2.

RHEOLOGICAL PROPERTIES

One of the main rheological properties of soils is their plasticity.

Plasticity is the ability of soils to change their shape (deform) under the influence of external forces (without breaks or cracks) and maintain the resulting shape after the cessation of mechanical action

Plasticity is characterized by the Atteberg number. The upper limit of plasticity is considered to be the humidity at which the soil begins to flow, and the lower limit is the humidity at which the soil stops rolling into a cord without cracks with a diameter of more than 3 mm.

I) upper limit of plasticity, or yield limit, - mass soil moisture at which a standard cone, under the influence of its own mass (76 g), is immersed in the soil sample by 10 mm;

2) the lower limit of plasticity - the boundary between the semi-solid and plastic state of the soil - mass humidity at which the sample can be rolled into a rope with a diameter of 3 mm without the formation of breaks and cracks;

3) plasticity number - the difference between the numerical expression of the upper and lower limits of plasticity. The plasticity number shows the moisture range within which the plastic properties of soils appear.

Sands have a plasticity number - 0,

sandy loam - 0-7,

loams - 7-17,

clay - more than 17.

Plasticity is determined by the granulometric composition and shape of the particles that make up the soil.

The plasticity of clays is twice that of loams and three times that of sandy loams.

Sands are practically non-plastic. The plasticity numbers for them are respectively 35-40, 10-20, 5-10 and 0.

Swelling particles of lamellar and scaly shape have the greatest plasticity.

All other things being equal, soils containing montmorillonite minerals in the clay fraction will always be more plastic than soils with a predominance of kaolinite.

Soil plasticity is widely used in determining the mechanical composition of soils, when rolling cords and balls, and when calculating traction forces for soil cultivation.

Plasticity determines soil consistency- the degree of mobility of soil particles under the influence of mechanical action at different humidity levels.

There are several forms of consistency:

a) solid - the soil has the properties of a solid body and is not plastic;

b) semi-solid - a transition state between a solid and a plastic body;

c) viscoplastic - the soil is plastic, but does not stick to other bodies;

d) sticky-plastic - the soil is plastic and sticks to other bodies;

e) viscous - the soil is able to spread in a thick layer;

f) fluid - the soil can spread in a thin layer.

Under normal conditions, soils are characterized by the first four forms of consistency. However, in some soils with severe waterlogging, fluid states are also observed in certain periods. They define mobility (creep) soil - its ability to flow in a waterlogged state under the influence of its own mass. Soil fluidity is actively manifested in the tundra, as well as on slopes in zones of groundwater wedging out. In this case, specific solifluction forms of relief are created

A special case of turnover - thixotropy, when waterlogged soils become fluid under mechanical influence and again turn into a solid state at rest. A similar phenomenon causes the high vulnerability of tundra landscapes, when even with small mechanical influences, thixotropic masses slide along aquicludes and frozen infertile soils come to the surface

Fluidity (creep) also has a certain influence on the development of erosion processes on slopes

Soil plasticity is associated with their viscosity- internal friction that occurs when the soil “flows”.

Soil viscosity should be studied when studying erosion processes, as well as when calculating production characteristics associated with soil cultivation.

Stickiness- the property of dispersion systems to stick to the surface of various bodies. Soil stickiness is quantitatively characterized by the force in newtons required to lift a metal plate from the soil surface and is expressed in N/cm2 (9.8 Pa).

Stickiness appears only in a wet state, which is due to molecular adhesion forces that arise at the interfaces between mineral particles, a thin layer of water and the surface of the contacting object. Thus, the decisive role in the manifestation of stickiness belongs to weakly bound water, and this property is called adhesion, and the water layer is called the adhesion layer.

The stickiness of soils is closely related to the granulometric composition, structure of soils, and their composition. All this determines the nature and properties of the interface between the soil and the plane of the object.

Dispersion at any level increases the internal surface area, enhances the hydrophilicity of soils, and causes an increase in its stickiness. Thus, the stickiness (in N/cm2) of sands and sandy loams (all other things being equal) is 0.2-0.3, cover loams - 0.6, clays 5-6, mineral particles less than 1 mmk - 10-11.

Destructuring of soils and disruption of their composition also increase stickiness.

The stickiness of soils is largely determined by their moisture content, therefore the main indicators of stickiness are:

a) initial adhesion humidity (W0);

b) humidity of maximum adhesion (Wmax);

c) moisture content of maximum stickiness (L).

The dependence curves of stickiness on moisture have a certain form (Fig.), however, the values ​​of V0, Wmax and L for different soils are different.

Stickiness, causing the connection between individual soil particles, plays a crucial role in the formation of macrostructure.

Stickiness determines such an important production property of soils as their physical ripeness.

Based on stickiness, soils are divided into extremely sticky (>147 Pa), highly viscous (49.0-147 Pa), average (19.6-49.0 Pa), slightly viscous (19.6 Pa).

Soil ripeness- a condition in which it does not stick, crumbles well, has the lowest resistivity and does not generate dust.

There are physical and biological ripeness.

Physical ripeness observed at optimal humidity, which ranges from 40-60% of the total moisture capacity, at which the ability of soil particles to stick to agricultural implements disappears, but the ability to self-aggregate appears.

The lower limit of physical ripeness is different for different soils; therefore, the stickiness of soils determines the optimal timing and conditions for conducting field work on specific soil varieties. The earliest soils of light granulometric composition and humified chernozems reach a state of physical ripeness.

Biological ripeness, according to D.I. Mendeleev, a condition of the soil in which it “fits like dough” due to the presence of carbon dioxide in it or the maximum biological activity of microorganisms (decomposition and processing of organic substances, release of nutrients).

Of great importance for characterizing the stickiness of soils are factors external to them, such as the power and weight of agricultural implements, the speed of their movement on the field, the condition of their surface, and the material from which the cutting parts are made. Taking into account soil and external factors that determine soil adhesion is an important reserve for saving energy resources when planning and carrying out field agricultural work.

Swelling- this is the property of soils and clays to increase their volume when moistened.

Swelling is based on the property of colloids to absorb water and form hydration shells around mineral and organic particles, pushing them apart. The larger the internal surface of the soil mass, the greater the water-holding capacity of soil particles, the more powerful the film they can create around themselves, the greater the swelling of such a system. However, the main role in soil swelling belongs not so much to the dispersion of the mineral base as to its mineralogical composition.

Clays swell more, especially those consisting of montmorillonite and saturated with Na or Li. Swelling is expressed in volume % relative to the initial volume according to the formula.

Shrinkage- reduction in soil volume when it dries out. This phenomenon is the opposite of swelling, depending on the same conditions as swelling. Measured in volume % relative to the original volume using the formula

When shrinking, the soil may become covered with cracks, the formation of structural aggregates, rupture of roots, and increased evaporation are possible. Shrinkage causes a change in the decomposition processes of organic matter and an increase in soil aerobiosis.

Shrinkage is characterized by a decrease in the volume of soils as they dry out and dehydrate.

The ability of soils to swell (shrink) is characterized by the following parameters:

1) degree of swelling (shrinkage) , measured by the change in volume of a soil sample upon wetting (drying) and expressed as a percentage of the original volume

2) moisture swelling - humidity percentage at which swelling stops. The swelling moisture content depends on the initial soil moisture content; the lower it is, the higher the swelling moisture content, the greater the degree of swelling. Consequently, overdrying of soils increases the amplitude of volumetric changes associated with swelling and shrinkage, which causes an increase in swelling pressure;

3) swelling pressure , which appears in the soil when volumetric deformations within the soil profile are impossible or limited. It can be measured using an external load and is equal to the force at which there will be no change in volume when humidified. There is a direct relationship between the degree and pressure of swelling;

4) deformation stresses , which appear in the soil during drying and contribute to the formation of cracks on the surface of the soil and structural units.

Swelling and shrinkage are observed to one degree or another in all soils, but to the greatest extent they are characteristic of drained soils and solonetzes, which determines their extremely unfavorable physical properties. The high swelling of fused smectite soils is a diagnostic feature and creates their specific appearance and structure. High pressures that appear inside the soil when they are moistened and swollen lead to the bulging of the soil mass and the formation of hummocky microrelief - gilgai .

When drying, tensile stresses cause cracking of soils and the formation of massive fused pedestals and blocks, very dense and hard. Deep fissuring promotes mixing of the soil mass (particles from the surface fall into cracks) and leads to the formation of a powerful but undifferentiated profile.

It is important to take into account the physical and mechanical properties of soil for various types of use of soils and soil cover: during mechanical tillage of soil in agriculture, when using soils as a foundation for structures, during road and airfield construction, when using soil as a building material, in hydraulic engineering during construction canals and reservoirs, during hydrotechnical soil reclamation (irrigation and drainage), etc. Favorable physical and mechanical properties help reduce the cost of all types of soil use, while unfavorable ones can significantly increase its cost and in some cases make it impossible.

THERMAL PROPERTIES OF SOIL

Temperature fluctuations are an important component of soil microclimate. Following the annual cycles of air temperature changes, soil temperature has a significant impact on many processes occurring in it.

HEAT RECEIPTS INTO THE SOIL

Thermal energy in the soil has several sources:

1) radiant energy of the sun;

2) atmospheric radiation;

3) internal heat of the globe;

4) the energy of biochemical processes of decomposition of organic residues;

5) radioactive decay.

The contribution of the last two sources is negligible and is usually not taken into account in balance sheet calculations.

The internal heat of the globe is also insignificant. The contribution of this source to the heat flow is large only in areas of active volcanic activity.

Atmospheric radiation becomes significant in the heat balance in areas with unstable atmospheric activity, during periods of invasion of warm or cold air masses.

Thus, the main source of heat in the soil is the radiant energy of the sun.

The actual amount of solar thermal energy entering the soil is significantly correlated with geographic latitude, time of year, state of the atmosphere, slope exposure, i.e., the angle of incidence of sunlight on the surface, the nature of the vegetation cover, as well as the thermal properties of the soil itself

THERMAL CHARACTERISTICS OF SOIL

The set of properties that determine the ability of soils to absorb and move thermal energy within their thickness is called thermal properties.

These include: heat reflectivity of soils, heat capacity, thermal conductivity, heat digestibility.

1. Thermal reflectivity of soils, or the ability of soils to reflect a certain proportion of solar radiation incident on its surface, is characterized by the value albedo(A) - the share of short-wave solar radiation reflected by their surface (Q OTR), expressed as a percentage of the total solar radiation (Qtot):

A=Q OTP /Qtotal 100,

where Qtot and Q OTP are expressed in J/(cm2 min).

Albedo depends on many properties of soils - their color, quantity and qualitative composition of organic matter, granulometric composition, structure, surface condition, humidity.

The range of reflection of radiant energy by the soil surface ranges from 8-10 to 30%.

Natural variation in albedo in landscapes is enhanced by the nature of vegetation and snow cover.

2. Heat-absorbing the ability of soils in the same region determines the division of soils into cold and warm: dark-colored soils are warmer than light-colored ones; structured soils with a rough surface are warmer than structureless soils.

The main and most important property of soils is fertility. Plants are anchored in the soil by their roots, and from it they receive minerals, water and oxygen.

If the climate determines the possibility of cultivating grapes in a particular area, affects the sugar content and acidity of berry juice, and mainly determines the production specialization of viticulture and winemaking, then the soil forms the harvest and its main qualities: it gives the berries and their processed products shades of taste and aroma, often elusive by chemical analysis, but perceptible by organoleptic evaluation.

In all countries of the world where climatic conditions allow grapes to be grown, their plantings are found on soils of different chemical and mechanical composition. It grows on chernozems and soddy-podzolic soils, on gray soils and brown soils, red soils and chestnut soils, on infertile sands and rocky soils that are almost infertile for other agricultural crops.

In this regard, it is sometimes believed that grapes are not picky about soils and any of them is quite suitable for it, except wetlands, saline soils and solonetzes. In fact, the grape plant, for all its plasticity, is demanding on soil conditions.

Loose, non-saline soils with sufficient nutrients and optimal moisture contribute to strong growth, abundant fruiting and longevity of grape plantings.

The presence of harmful salts in the soil or constant waterlogging, on the contrary, reduces the productivity of plantings and often leads to their death.

Science and practice have numerous data confirming the influence of soil on the size and quality of the crop. Thus, according to A. A. Egorov, plantings of the Tavkveri variety produce grapes from which excellent table and dessert wines are prepared, while the same variety grown in the Kara-Chanakh department produces wines of mediocre quality.

According to A.P. Chefranov, the soils of the first two sections are gray-chestnut loamy, formed on loess-like loams, and the third - gray-chestnut crushed stone loam, underlain at a depth of 80-85 cm by boulder-pebble sediments. The Rkatsiteli variety behaves opposite to Tavkveri. The best dessert wines of Kara-Chapakh are made from grapes grown on gray-chestnut gravelly loamy soils.

In the same country, the best table grapes are produced by the vineyards of the Absheron Peninsula, where the soils are sandy, formed on sea sands and shell rocks. It is well known that on the Black Sea coast of Crimea, the Krasnodar Territory, in the valley of the Alazani River (Kakheti), many years of practice have identified soils and areas for a number of varieties where the highest and highest quality yields are obtained.

Without exaggeration, we can say that all grape varieties are sensitive to changing soil conditions, especially rootstock varieties. It does not follow from this, however, that, regardless of the natural zone or region, the most valuable soils exist only for certain varieties and a certain quality of crop.

For example, for black Pinot and Chardonnay varieties, from which first-class champagne wines are made, the best soils are considered to be brown mountain forest and humus-carbonate soils, but this is only true for certain areas that have their own specific natural conditions (Abrau-Durso, Champagne).

In the area of ​​distribution of the same soils, but with slightly different natural conditions (Kakheti), these varieties do not produce high-value champagne wine materials, while other varieties (Rkatsiteli, Khikhvi, Saperavi, Cabernet) provide material for the preparation of first-class table wines.

Very good champagne wines are produced in the Alma-Ata region and Kyrgyzstan from black Pinot and Riesling, growing on dark chestnut soils and chernozems.

If we compare the climate and other natural conditions of these places, then you can see that they differ markedly from each other. It follows that it is necessary to evaluate the qualities of each soil for a grape plant, its varieties and the production purpose of the crop in comparison with other soils within each natural zone and region, and not in comparison with soils in other natural zones. Moreover, soil assessment must be carried out in conjunction with other natural conditions.

Any gardener knows that when growing garden crops, the yield on his plot depends primarily on the soil, its composition and properties. It is known that each natural zone has its own special climatic conditions. Due to such differences in weather conditions, different types of soils are formed, which also have different characteristics.

Basic soil properties

All soils differ in appearance, structure and many other characteristics. They evaluate the composition of the soil and assign it to one type or another. Here are the main criteria for soil quality:

Color is an external property, a description of the soil, according to which it can be classified as chernozem, gray soil, red soil or yellow soil. Of course, the color depends entirely on how moist the soil is and what is included in its composition. For example, a greater amount of humus colors the soil dark or even black. A whitish color indicates the presence of salts - calcium, magnesium, gypsum, silicon and the leaching of minerals. Red and brown tones indicate the presence of iron and manganese in the rock.

This indicator is not as simple as it seems. Humidity depends not only on meteorological conditions.

Simply put, if you saturate different types of soil with moisture, it will look different. They are influenced by underground flows, groundwater levels, and the mechanical composition of the soil mixture.

For example, the predominance of large sand particles does not retain moisture, allowing it to pass into the lower layers. Water also evaporates quickly from this type of soil. The presence of clay particles leads to an increase in its moisture capacity.

Description and characteristics of species

The soils that gardeners, gardeners, and agronomists most often work with are:

• sandy;
• sandy loam;
• loamy;
• clayey;
• peat.

Properly organizing planting means knowing the characteristics of the soil and how to improve its properties through proper cultivation, application of the necessary minerals and fertilizers.

This is a light type of soil consisting mainly of sand grains and a small portion of clay particles. It allows water to pass through well and is extremely free-flowing. If you take a handful of earth in your palm, you won’t be able to form a lump out of it. She's falling apart. Its other qualities are high breathability, thermal conductivity, and easy workability. It is difficult to apply fertilizers to such soil. They do not stay there, they go along with the water into deeper ground layers.

Such lands are poor and not very suitable for growing crops. But growing garden trees, as well as carrots, onions and strawberries on it is quite acceptable. To cultivate sandstone, it is good to introduce peat, humus and clay flour.

Sandy loam type

This soil has the best properties, is similar in composition to sandy, but still contains a higher percentage of clay impurities. By taking a handful in your hand and squeezing it, you can get a lump. But it doesn't hold its shape well. The qualities of such soil are more valuable. It retains moisture and minerals better, is breathable, dries out more slowly, warms up better, and is easier to process. You can grow all crops, not forgetting about methods of increasing soil fertility. Ways to improve such soil: applying potash and organic fertilizers, mulching, green manure and fairly frequent loosening.

Loamy lands

The best type of soil in terms of characteristics is also called loam. Contains the largest percentage of nutrients. It retains moisture well and is endowed with the ability to distribute it throughout the horizon. Easy to handle and retains heat. Such a sample forms a lump well and can be rolled out into a “sausage”, but cannot be bent into a ring. This is a special technique in agronomy for determining the mechanical composition of the soil. Such land does not need to be improved, but only to maintain its fertile properties, for which purpose it is mulched and humus is added when digging in the autumn.

The soil is clay

Or clayey, as it is also called. Clay content up to 80%. It is very heavy and dense, does not absorb water well, and sticks to shoes when wet. The structure is lumpy.

If you take a lump of damp earth, you can easily form a long sausage and roll it into a ring. At the same time, it will not crack or tear.

We can say that it looks like plasticine. Accordingly, its qualities deteriorate: it contains little air, does not warm up well and allows water to pass through. It is not easy to grow garden crops on such land.

Proper cultivation will help such land become fertile. To do this, lime, ash, compost, and manure are regularly added. Careful loosening and mulching will also be beneficial.

Acid balance

Soil acidity plays a huge role in growing crops., the optimal value of which is called acid-base balance. It is one of the most important indicators of the quality of fertile land. Acidity is indicated by the “pH” symbol. When this value is equal to seven units, the acidity is called neutral. If the pH is below seven the earth is acidic. A pH above seven is called alkaline.

With increasing acidity, there is an increase in the content of aluminum and its salts in the soil, as well as manganese and other minerals. This prevents plants from developing normally. Moreover, in such soil, pathogenic bacteria, microorganisms and pests begin to actively multiply. The applied fertilizers do not decompose. All this leads to soil imbalance.

Determining acidity is very easy at home. To do this, use a simple method of litmus indicators. Soils are very often acidified. The most common method is liming. At the same time, lime displaces aluminum and its salts from the top layer of the earth, replacing them with calcium and magnesium. This reduces the toxic effect on the plant.

The amount of lime per square meter depends on the type of soil and its characteristics. The table shows the rates for applying lime to reduce acidity.

The principle is simple: the heavier and clayier the soil, the more lime it needs. It is important to remember that when applying lime, boron fertilizers are applied at the same time. Acidity should be checked periodically if adjustments need to be made.

After all, this indicator affects the fertility of the land, and, accordingly, the yield.

types of soils

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

Basic soil properties

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

Fertility

Soil fertility is usually understood as the entire set of its properties and processes occurring within it 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%).

All these components are closely related to each other, so you should not be surprised if the lack of one component or the disruption of any process provokes a change in all the others. Since time immemorial, people have assessed the quality of soil precisely from the point of view of fertility, on which the abundance of the harvest and the beauty of ornamental plants depend.

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

Mechanical composition

Mechanical composition is another very important property that allows you to classify the soil as a certain variety. By and large, this concept refers to 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. The features of the mechanical composition are based not only on the initial characteristics of the parent rock, but also on the parameters of the soil formation processes 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 further.

What does fertility depend on and how to increase it

Of course, for any agrarian or simple summer resident who grows various plants on his plot, the primary task will be to increase soil fertility, which should increase the amount of crops grown. Let's consider the main factors of soil maintenance and ways to achieve the desired result.

Fertility Maintenance Factors

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

The main such factors include:

• amount of water in the soil;
• rainfall and irrigation (increased sodium accumulation can have a detrimental effect on the crop being grown);
• the value of total moisture evaporation, which will confirm the general increase in liquid volume throughout the year;
• sufficient level of nutrients.

Did you know? The process of soil formation occurs very slowly. Thus, it takes almost a century to form just 0.5–2 cm of its fertile layer.

Ways to increase fertility

The most important conditions on which fertility will depend include temperature, nutritional, water-air, biochemical, physicochemical, salt and redox regimes.
A person can influence the characteristics of some of them by taking the following measures:

1. By organizing competent crop rotation by planting crops in the same place at five-year intervals. That is, no matter what you grow, it is advisable to change the place where the crop grows every five years.
2. Sowing so-called “healing plants” on the site, among which garlic, wormwood, shepherd’s purse, and nettle stand out.
3. Attracting earthworms. It has long been established that with a large accumulation of them, the soil produces higher yield volumes, which means their presence is very desirable (California species are distinguished by increased digestibility of various organic matter).
4. Carrying out heat treatment to destroy all kinds of pests and weeds. The main disadvantage of this method is the impossibility of using it over large areas (more relevant for greenhouses and greenhouses).
5. By introducing organic matter into the soil, especially manure, ash and compost.
6. Carrying out mixed planting of crops. Along with the cultivated plant, experts recommend planting a suitable “neighbor” that will repel pests and prevent depletion of the substrate. For these purposes, you can plant basil, rosemary, chamomile, marigolds, which, among other things, will be very attractive to bees, thereby promoting plant pollination and increasing harvest volumes.
7. Organizing periodic rest for each individual section of the territory. With constant, continuous cultivation of the same crops, any soil gets tired, so during the selected year it is better not to plant anything at all, doing only weeding, mulching and fertilizing. With the arrival of autumn, the site is dug up, trying to move the top layer down.
8. Sowing green manure plants that have a high content of protein, starch and nitrogen. In this case, the ideal “residents” of your plot will be oats, rye, mustard, and sunflower. They are generally sown after harvest, although in some cases they are grown simultaneously with the main crops.

It is much easier to increase the fertility of closed soil than to achieve a similar result in an open area, so it is not surprising that many summer residents set up greenhouses and hotbeds on their territories, providing them with irrigation and ventilation systems, and sometimes even heating.

Mechanical composition and its effect on the soil

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

What is mechanical composition

The structure of the earth contains particles of very different sizes: both stones, remains of rocks and mineral compounds (often reaching 10-12 cm in diameter), and very small elements invisible to the naked eye. Moreover, you cannot see some of them even with a regular 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 sizes 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 (size 0.0001 mm). Let us consider the most typical types of soils, identified on the basis of their mechanical composition.

Soil types depending on composition

Even if you do not have special equipment, and you cannot determine the type of soil mixture by eye, the following diagnostic methods (dry and wet) will tell you about its approximate mechanical composition.

Clayey

This substrate contains up to 50% pure clay and is characterized by such definitions as “damp”, “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 area: wet clay sticks to gardening tools.
In a dry state, it is very difficult to rub such soil with your fingers, but when you succeed, you get the feeling that you have a homogeneous powder in your hands. When wet, it begins to smear heavily, rolls perfectly into a cord and allows you to form a ring from the soil without any problems.

Sandy loam

Unlike the first option, dry sandy loam soils are easily rubbed with your fingers and in this state allow you to see small grains of sand with the naked eye. If you wet the substrate and try to load it into the string, you will only get a small part. In this case, along with clay, the substrate also contains sand, of which there is noticeably more (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 sand grains, with a small addition of clay or dust particles. This type of substrate is structureless and is not characterized by cohesive properties.

Loamy

When you rub dry loam between your fingers, you get a fine powder with palpable grains of sand. Once moistened, it can be rolled into a cord that breaks when attempting to form a ring. Light loams will not allow you to form a ring, and the cord will crack when rolling. Heavy loamy substrates allow you to get a ring with cracks. Loamy soils themselves are already rich in mineral compounds, and they are also characterized by fairly high looseness, do not prevent the passage of moisture into the lower layers and ensure normal air circulation.

If the earth consists of small particles of silt and larger particles of sand, then it is of higher quality. To determine the proportions of these substances, you can conduct a small home study. Take a soil sample from your site, place it in a container of water and stir until it is not too liquid. First make a ball from the resulting solution, and then try to make a rope.
Of course, the final result plays the main role in this matter. That is, if you don’t get either a ball or a rope, then you have sand in front of you, and if you managed to form a ball, then you can assume the presence of sandy loam. Only loam is suitable for forming a rope, and if it folds into a ring, then it is most likely clay. The final and most accurate conclusion about the mechanical composition of the soil mixture can only be made on the basis of the results of laboratory tests during the office period.

The influence of the composition on the future harvest

A lower or higher content of 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 of the usual garden plants will be quite uncomfortable, if they can take root there at all. Planting in loamy or sandy loam soils can bring greater results, but they cannot compare with chernozems fertilized with organic matter and mineral compounds.

Physical properties of soil

The main physical properties of soil that 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 there is no need to talk about good water, air permeability or aeration. Let's look at this issue more carefully.

Density (bulk mass)

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 consequence, the development of the roots of cultivated crops.

As for the level of soil density, it depends on the properties of the minerals that form the solid phase, granulometric components, content and structure of organic components. The optimal value for the density of the arable horizon for most of the vegetable crops grown in our country is considered to be 1.0-1.2 g per cubic meter. cm.

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

1. Fused or very dense composition, 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 drained chernozem soils and columnar solonetzes.
2. A dense structure in which the shovel penetrates the ground no more than 4-5 cm, and the substrate itself is difficult to break. Typical for heavy, clayey and uncultivated soils.
3. Loose structure - agricultural tools easily go deep into the ground, and the soil itself is well structured. These are sandy loam soils and upper, well-structured loam horizons.
4. The crumbly texture is characterized by the high flowability of the soil, the individual particles of which are loosely connected to each other. This option is typical for sandy loam and structureless substrates.

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

Porosity

Porosity is the exact opposite of density above, and from a scientific point of view it is the total volume of all free space (pores) between the solid components 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, pores do not always have the same shape and diameter, therefore, based on their sizes, 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 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 negatively 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.

10 once already
helped

Each of us who is at least a little familiar with biology understands that the success of growing garden crops depends immediately on a combination of many diverse factors. Climatic conditions, planting dates, variety, timeliness and competence of agrotechnical methods - these are not all that have a direct impact on the harvest.

Chernozem, soil rich in humus. © NRCS Soil Health

One of the fundamental factors that often plays a dominant role in the outcome of planting a garden and setting up a vegetable garden is the type of soil. The possibility of growing certain crops, the need for certain fertilizers, and the frequency of watering and weeding will depend on the type of soil on your site. Yes Yes! All this can have significant differences and be beneficial or detrimental if you do not know what kind of soil you are dealing with.

Main types of soils

The main types of soils that Russian gardeners most often encounter include: clayey, sandy, sandy loam, loamy, calcareous and marshy. Each of them has both positive and negative properties, which means they differ in recommendations for improving and selecting crops. In their pure form they are rare, mostly in combination, but with a predominance of certain characteristics. Knowing these properties is 80% of the success of a good harvest.

Clay soil. © nosprayhawaii

It is quite easy to identify clay soil: after digging, it has a coarse, lumpy, dense structure, sticks to your feet when it rains, does not absorb water well, and sticks together easily. If you roll a long sausage from a handful of such soil (wet), it can be easily bent into a ring without it falling apart or cracking.

Due to its high density, such soil is considered heavy. It warms up slowly, is poorly ventilated, and has a low water absorption coefficient. Therefore, growing crops on it is quite problematic. However, if clay soil is properly cultivated, it can become quite fertile.

To lighten and enrich this type of soil, periodic application of sand, peat, ash and lime is recommended. Sand reduces moisture holding capacity. Ash enriches with nutritional elements. Peat loosens and increases water absorption properties. Lime reduces acidity and improves the air regime of the soil.

How much to add is an individual question, directly related to the characteristics of your soil, which can only be accurately determined in laboratory conditions. But, in general: sand - no more than 40 kg per 1 m², lime - about 300-400 g per m², for deep digging once every 4 years (on soils with a slightly acidic reaction), there are no restrictions for peat and ash. If you have a choice of organic matter, then the best option for increasing the fertility of clay soils is horse manure. Sowing green manures such as mustard, rye, and oats will also not be useless.

Plants growing in clay soils have a hard time. Poor heating of the roots, lack of oxygen, stagnation of moisture, and the formation of soil crust do not benefit the crop. But still, trees and shrubs, having a fairly powerful root system, tolerate this type of soil well. Vegetables that grow well on clay are potatoes, beets, peas and Jerusalem artichokes.

For other crops, we can recommend high beds, planting on ridges, using a shallower depth for planting seeds and tubers in the soil, and planting seedlings in an inclined manner (for better heating of the root system). Among agricultural practices, special attention on clay soils should be paid to loosening and mulching.

Sandy soil. © extension

Sandy soil is a light soil type. It will also not be difficult to recognize it: it is loose, free-flowing, and easily allows water to pass through. If you pick up a handful of such earth and try to form a lump, nothing will work.

All the qualities inherent in sandy soils are both their advantage and their disadvantage. Such soils warm up quickly, are well aerated, easy to cultivate, but at the same time they cool quickly, dry out quickly, and poorly retain minerals in the root zone (nutrients are washed away by water into the deeper layers of the soil). As a result, they are poor in the presence of beneficial microflora and are poorly suitable for growing any crops.

To increase the fertility of such soils, it is necessary to constantly take care of improving their compaction and binding properties. Regular application of peat, compost, humus, clay or drill flour (up to two buckets per 1 m²), the use of green manure (with incorporation into the soil), and high-quality mulching after 3-4 years give a decent, sustainable result.

But even if the site is still in the process of cultivation, you can grow carrots, onions, melons, strawberries, currants, and fruit trees on it. Cabbage, peas, potatoes and beets will feel somewhat worse on sandy soils, but if you fertilize them with fast-acting fertilizers, in small doses and often enough, you can achieve good results.

For those who don’t want to bother with cultivation, there is another way to improve these soils - creating an artificial fertile layer by claying. To do this, in place of the beds, it is necessary to build a clay castle (lay out the clay in a layer of 5-6 cm) and pour 30-35 cm of sandy loam or loamy soil taken from the side onto it.

Sandy loam soil. © pictonsandandsoil

Sandy loam soil is another option for soils with a light mechanical composition. In terms of its qualities, it is similar to sandy soils, but contains a slightly higher percentage of clay inclusions, which means it has a better holding capacity for mineral and organic substances, not only warms up quickly, but also retains heat for a long time, allows less moisture to pass through and dries out more slowly, is well aerated and easy to process.

You can determine it by the same method of squeezing a handful of damp soil into a sausage or lump: if it forms but does not hold its shape well, you have sandy loam soil.

Anything can grow on such soils using conventional agricultural techniques and the choice of zoned varieties. This is one of the good options for gardens and vegetable gardens. However, methods for increasing and maintaining fertility for these soils will also not be superfluous. It is recommended to regularly apply organic matter (in normal doses), sow green manure crops, and mulch.

Loamy soil. © gardendrum

Loamy soil is the most suitable type of soil for growing garden crops. It is easy to process, contains a large percentage of nutrients, has high air and water permeability, is capable of not only retaining moisture, but also distributing it evenly throughout the horizon, and retains heat well. If you take a handful of such earth in your palm and roll it, you can easily form a sausage, which, however, cannot be bent into a ring, since it will fall apart when deformed.

Due to the combination of existing properties, loamy soil does not need to be improved, but only to maintain its fertility: mulch, apply manure (3-4 kg per 1 sq.m.) during autumn digging and, as necessary, feed the crops planted on it with mineral fertilizers. Anything can be grown on loamy soils.

Calcareous soil. © midhants

Calcareous soil is classified as poor soil. It usually has a light brown color, a large number of rocky inclusions, is characterized by an alkaline environment, at elevated temperatures it quickly heats up and dries out, does not release iron and manganese to plants well, and can have a heavy or light composition. The foliage of crops grown on such soil turns yellow and unsatisfactory growth is observed.

To improve the structure and increase the fertility of calcareous soils, it is necessary to regularly apply organic fertilizers, not only for basic cultivation, but also in the form of mulch, sow green manure, and apply potash fertilizers.

Anything can be grown on this type of soil, but with frequent loosening of row spacing, timely watering and thoughtful use of mineral and organic fertilizers. The following will suffer from weak acidity: potatoes, tomatoes, sorrel, carrots, pumpkin, radishes, cucumbers and salads, so they need to be fed with fertilizers that tend to acidify rather than alkalize the soil (for example, ammonium sulfate, urea).

Peat medium-decomposed horizon of sod-podzolic soil. © own work

Swampy soil

Swampy or peaty soils are also used for setting up garden plots. However, it is quite difficult to call them good for growing crops: the nutrients they contain are not readily available to plants, they absorb water quickly, but release water just as quickly, do not warm up well, and often have a high acidity level. But such soils retain mineral fertilizers well and are easy to cultivate.

To improve the fertility of swampy soils, it is necessary to saturate the soil with sand (for this it is necessary to carry out deep digging so as to lift the sand from the lower layers) or clay flour, in particularly acidic varieties, use abundant liming, take care of increasing the content of beneficial microorganisms in the soil (apply manure, slurry, compost, do not ignore microbiological additives), do not forget about potassium-phosphorus fertilizers.

If you are planting a garden on peat soils, it is better to plant trees either in holes with individually laid soil for the crop, or in bulk hills with a height of 0.5 to 1 m.

Carefully cultivate the soil under the garden, or, as in the case of sandy soils, lay a clay layer and add loam mixed with peat, organic fertilizers and lime onto it. But if you grow only gooseberries, currants, chokeberries and garden strawberries, then you don’t have to do anything - just water and pull out the weeds, since these crops can grow on such soils even without cultivation.

Chernozem. © carlfbagge

Chernozems

And, of course, speaking about soils, it is difficult not to mention black soils. In our summer cottages they are not found so often, but they deserve special attention.

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

In addition, chernozems can hardly be called light soils; therefore, they are often loosened by adding sand or peat. They can also be acidic, neutral and alkaline, which also requires its own adjustment.

Chernozem. © Axel Hindemith

To understand that you really have black soil in front of you, you need to take the guest of the earth and squeeze it in your palm; a black, greasy imprint should remain on your hand.

Some people confuse black soil with peat - here, too, there is a way to check: squeeze out a wet lump of soil in your hand and put it in the sun - the peat will dry instantly, but the black soil will retain moisture for a long time.