Layers and surface of the soil. Fertile soil layer: composition and characteristics Name top soil layer
Topsoil, densely overgrown herbaceous plants, in soil science is called turf. The well-being of the country depends on the fertility of this horizon. It is not for nothing that Franklin Delano Roosevelt (thirty-second President of the United States) said that a people who destroys the soil ultimately destroys itself.
The process of soil formation: why is fertility different everywhere?
To form soils on globe several stages are typical. First, the destruction of rocks occurred under the influence of temperature changes, wind, and water. Small pieces formed rubble - these are primary minerals (quartz, etc.). It gave organic matter the opportunity to settle.
The first settlers were mosses, lichens, and microorganisms. Their vital activity changed the layer itself, it became already suitable for existence in it higher plants. The next stage already depended on the climate: what more favorable conditions(higher temperature, less moisture, absence of prolonged frosts), the easier and faster the further process went. That is, in the southern regions, soils form faster than in the northern ones. The terrain affects this - the slopes cannot absorb moisture completely, the water runs down and stagnates there: the soils on the slopes and in the lowlands are different.
To summarize, we can say that different areas differ in mechanical composition - from sand to clay, in chemical composition - from turf to podzolic, water regime- from normal-natural to excessive. They are found very rarely in pure form, forming different subtypes under the influence of various natural factors.
What is the top layer of soil called?
(vertical section) has several layers called horizons. The top fertile layer is called humus, the next is transitional, and the last is soil-forming.
The future of the planet depends on the thickness and composition (fertility) of the humus horizon. Unreasonable human influence has a detrimental effect on the condition of the soil - improper use of soil cultivation techniques to obtain ultra-high yields destroys the humus layer, and its erosion occurs. Deforestation and frequent fires are changing the green appearance of the planet. Wind and precipitation complete the destruction.
Living microorganisms work on it. Their living environment is: plant debris (grass, hay, fallen leaves, branches, mushrooms), animal debris (worms, insects, bacteria, microorganisms). Organics and chemical compounds, called humus, make up the humus horizon. Microflora and microfauna working to form and restore fertile soils are called microbiocenosis.
Layers of fertile soil
Mulch is the first layer of fertile soil.
This layer is under our feet - plant and animal remains. Under their layer live beetles, various worms, flies, and fleas. Their number can reach several tons per hectare. All this huge number of small creatures lead a fairly active lifestyle: they move, eat, reproduce, satisfy their natural needs, and ultimately die. Their remains decompose to their original state. The top layer of soil, densely overgrown with herbaceous plants, develops only under favorable conditions.
Vermicompost is the second layer of fertile soil.
It consists of waste products of microflora and microfauna of the first layer, their remains, and plant remains. In some areas its thickness is significant - up to 20 centimeters. Vermicompost serves as a medium through which plants not only receive adequate nutrition, but also maintain (develop) their immunity.
Ridiculous deep plowing (digging) destroys the layer of vermicompost, and the seeds sown after this process produce a frail plant.
Biomineral (third) layer of fertile soil.
The top layer of soil, densely overgrown with herbaceous plants, a layer of mulch protects the soil from drying out on the one hand, and on the other, allows moisture to penetrate deep inside. At the same time, decomposed plant remains are transported deeper along with vermicompost. Biochemical reactions occurring in this layer accumulate biomineral fertilizers for plant growth. The roots of plants, penetrating deeply into the soil (almost to the same depth as the height of the plants), receive complete nutrition from this layer.
The fourth layer of fertile soil is humus.
Microorganisms work in it under conditions of limited access to air and moisture, creating unique hydrocarbon compounds, carbon dioxide, methane and combustible biogases. This process is called biosynthesis, and it is what creates bionitrogen accumulations. This layer, on the one hand, warms the plants, and on the other, the plants, as well as microflora and microfauna, absorb the released carbon dioxide and methane. Thus, soil bionitrogen accumulations are formed.
Subsoil, clay - the fifth layer of fertile soil
It regulates moisture and gas exchange at a depth of more than 20 cm.
Classification of Russian soils according to V.V. Dokuchaev
Vasily Vasilyevich Dokuchaev (1846-1903), geologist and soil scientist, created a classification of Russian soils. Among the soils, according to their composition, he identified the following: clayey, sandy, loamy, peat, calcareous, turf, sandy loam.
Clayey
These are fertile, nutrient-rich, but difficult to cultivate soils. After drying they become very dense. To improve their structure, it is necessary to annually carry out a set of agrotechnical measures: digging, adding deciduous soil, manure, ash and peat.
Sandy
These are loose soils that easily permeate water. They are depleted in potassium and magnesium, require the application of litter, mineral fertilizers (in small doses) and only in this case can you get a top layer of soil overgrown with grass.
Loamy
These soils are very fertile: they are breathable on the one hand, and on the other hand they retain moisture well. But if you dig them up very often, a dense crust forms on top, preventing the flow of moisture.
Peat
These soils are sorely lacking in calcium and potassium and low in phosphorus. But if you add sand, lime and mineral fertilizers, after a while the soil will become monotonous and very fertile.
Limestone
There are quite a lot of such soils in Russia. Their composition is half lime, the rest clay or sand. In this case, the roots of the plants receive little water; it is retained by the crust on the surface.
Turf
The top layer of soil densely covered with herbaceous plants is the definition of turf. Such soils formed in vast open areas from St. Petersburg to Kaliningrad and Kamchatka. Moisture and abundance meadow grass created a special microclimate in the fertile layer, which enriches the planted plants with minerals and organic matter just as well as black soil. These soils have long been used as hayfields and pastures.
Sandy loam
These lands easily absorb moisture without forming a crust. They warm up very quickly. Agrotechnical techniques for them include the application of peat, compost and manure.
Modern classification of soils
Since the 50s of the twentieth century, a new systematization of soils has been established, taking into account diagnostic indicators for accounting for soil formation regimes and modern environmental conditions.
The newest classification was published in 2000. It is called profile-genetic and takes into account the structure of the soil profile and its properties.
The upper layer of the Earth, which gives life to the inhabitants of the planet, is just a thin shell covering many kilometers of internal layers. Little more is known about the hidden structure of the planet than about outer space. The deepest Kola well, drilled into the earth's crust to study its layers, has a depth of 11 thousand meters, but this is only four hundredth of the distance to the center of the globe. Only seismic analysis can get an idea of the processes occurring inside and create a model of the Earth’s structure.
Inner and outer layers of the Earth
The structure of planet Earth is made up of heterogeneous layers of internal and external shells, which differ in composition and role, but are closely related to each other. Inside the globe there are the following concentric zones:
- The core has a radius of 3500 km.
- Mantle - approximately 2900 km.
- The earth's crust is on average 50 km.
The outer layers of the earth make up a gaseous envelope called the atmosphere.
Center of the planet
The central geosphere of the Earth is its core. If you ask the question of which layer of the Earth has been studied practically the least of all, then the answer will be - the core. It is not possible to obtain accurate data on its composition, structure and temperature. All information that is published in scientific works was achieved through geophysical, geochemical methods and mathematical calculations and is presented to the general public with the clause “supposedly”. As the results of seismic wave analysis show, the earth's core consists of two parts: internal and external. The inner core is the most unexplored part of the Earth, since seismic waves do not reach its limits. The outer core is a mass of hot iron and nickel, with a temperature of about 5 thousand degrees, which is constantly in motion and is a conductor of electricity. It is with these properties that the origin of the Earth’s magnetic field is associated. The composition of the inner core, according to scientists, is more diverse and is supplemented by lighter elements - sulfur, silicon, and possibly oxygen.
Mantle
The planet's geosphere, which connects the central and upper layers of the Earth, is called the mantle. It is this layer that makes up about 70% of the mass of the globe. The lower part of the magma is the shell of the core, its outer boundary. Seismic analysis shows here a sharp jump in the density and velocity of longitudinal waves, which indicates a significant change in the composition of the rock. Composition of magma - mixture heavy metals, in which magnesium and iron predominate. Top part layer, or asthenosphere, is a mobile, plastic, soft mass with a high temperature. It is this substance that breaks through the earth's crust and splashes out to the surface during volcanic eruptions.
The thickness of the magma layer in the mantle is from 200 to 250 kilometers, the temperature is about 2000 o C. The mantle is separated from the lower globe of the earth's crust by the Moho layer, or the Mohorovicic boundary, a Serbian scientist who determined a sharp change in the speed of seismic waves in this part of the mantle.
Hard shell
What is the name of the layer of the Earth that is the hardest? This is the lithosphere, the shell that connects the mantle and the earth's crust, it is located above the asthenosphere, and cleanses the surface layer from its hot influence. The main part of the lithosphere is part of the mantle: of the total thickness from 79 to 250 km, the earth's crust accounts for 5-70 km, depending on the location. The lithosphere is heterogeneous; it is divided into lithospheric plates, which are in constant slow motion, sometimes diverging, sometimes approaching each other. Such vibrations of lithospheric plates are called tectonic movement; it is their rapid shocks that cause earthquakes, splits of the earth's crust, and the splashing of magma to the surface. The movement of lithospheric plates leads to the formation of trenches or hills, and solidified magma forms mountain ranges. The plates have no permanent boundaries; they connect and separate. Areas of the Earth's surface above faults tectonic plates- these are places of increased seismic activity, where earthquakes, volcanic eruptions occur more often than in others, and minerals are formed. On given time 13 lithospheric plates have been recorded, the largest of which are: American, African, Antarctic, Pacific, Indo-Australian and Eurasian.
Earth's crust
Compared to other layers, the earth's crust is the thinnest and most fragile layer of the entire earth's surface. The layer in which organisms live, which is most saturated chemicals and trace elements, makes up only 5% of the total mass of the planet. The earth's crust on planet Earth has two varieties: continental or continental and oceanic. The continental crust is harder and consists of three layers: basalt, granite and sedimentary. The ocean floor is made up of basalt (main) and sedimentary layers.
- Basalt rocks- These are igneous fossils, the densest of the layers of the earth's surface.
- granite layer- absent under the oceans, on land it can approach the thickness of several tens of kilometers of granite, crystalline and other similar rocks.
- sedimentary layer formed during the destruction of rocks. In some places it contains deposits of minerals of organic origin: coal, salt, gas, oil, limestone, chalk, potassium salts and others.
Hydrosphere
When characterizing the layers of the Earth's surface, one cannot fail to mention the planet's vital water shell, or hydrosphere. The water balance on the planet is maintained by oceanic waters (the main water mass), The groundwater, glaciers, continental waters of rivers, lakes and other bodies of water. 97% of the entire hydrosphere is made up of salt water in the seas and oceans, and only 3% is fresh water drinking water, of which the bulk is found in glaciers. Scientists assume that the amount of water on the surface will increase over time due to deep spheres. Hydrospheric masses are in constant circulation, pass from one state to another and closely interact with the lithosphere and atmosphere. The hydrosphere has a great influence on all terrestrial processes, development and vital activity of the biosphere. It was the water shell that became the environment for the emergence of life on the planet.
The soil
The thinnest fertile layer of the Earth called soil, or soil, together with the water shell, is of greatest importance for the existence of plants, animals and humans. This ball appeared on the surface as a result of the erosion of rocks, under the influence of organic decomposition processes. By processing the remains of vital activity, millions of microorganisms created a layer of humus - the most favorable for crops of all kinds land plants. One of the important indicators High Quality soil - fertility. The most fertile soils are those with an equal content of sand, clay and humus, or loam. Clayey, rocky and sandy soils are among the least suitable for agriculture.
Troposphere
The air shell of the Earth rotates along with the planet and is inextricably linked with all the processes occurring in the earth's layers. The lower part of the atmosphere penetrates deep into the body of the earth's crust through pores, while the upper part gradually connects with space.
The layers of the Earth's atmosphere are heterogeneous in their composition, density and temperature.
The troposphere extends at a distance of 10 - 18 km from the earth's crust. This part of the atmosphere is heated by the earth's crust and water, so it gets colder with height. The temperature in the troposphere decreases by approximately half a degree every 100 meters, and at the highest points reaches from -55 to -70 degrees. This part of the airspace occupies the most significant share - up to 80%. It is here that the weather is formed, storms and clouds gather, precipitation and winds form.
High layers
- Stratosphere - ozone layer planet that consumes ultraviolet radiation The sun, preventing it from destroying all living things. The air in the stratosphere is thin. Ozone maintains a stable temperature in this part of the atmosphere from - 50 to 55 o C. There is an insignificant amount of moisture in the stratosphere, so clouds and precipitation are not typical for it, in contrast to air currents of significant speed.
- Mesosphere, thermosphere, ionosphere- air layers of the Earth above the stratosphere, in which a decrease in the density and temperature of the atmosphere is observed. The ionospheric layer is where the glow of charged gas particles, called the aurora, occurs.
- Exosphere- sphere of dispersion of gas particles, blurred boundary with space.
Beneath it there is a low-fertile soil layer of 10-50 centimeters. Acid and water are washed out of it, which is why it is called a leaching horizon. Here, their own elements are released due to chemical, biological, physical processes, and clay minerals appear.
Deeper is the parent rock. It also contains useful elements. For example, calcium, silicon, potassium, magnesium, phosphorus and others.
Let's take a closer look at humus, since it plays a very important role in our lives.
Humus: education, concept
Soil is formed through the weathering of rocks and consists of organic and inorganic components. In addition, it contains air and water. This is just a diagram, but in fact, each layer develops separately in accordance with certain conditions. Our earth only seems homogeneous; it is inhabited by worms, insects, and bacteria.
The top layer of soil is its cover. In forests it is represented by organic remains and fallen leaves, on open areas- herbaceous vegetation. The cover protects the earth from drying out, hail, and cold. The remains of insects and animals decompose under it. During this decomposition process, the soil is naturally enriched with mineral elements.
Humus is inhabited by living organisms, permeated with the roots of trees and plants, and saturated with air. Its structure is loose, in the form of lumps. Here the formation and accumulation of nutrients by root systems occurs.
Any person knows that the top layer of soil, or rather humus, is very important for fertility. The substantia nigra contains carbon and nitrogen. This is a kind of kitchen where food for planting (active humus) is prepared. Also in this layer a balance of nutrients, water and air regimes (stable humus) is created.
What affects the fertile soil layer
The top layer of soil is affected by cultivation technology, type, climate, and crop rotation. In the garden, adding organic amendments and rotted compost can significantly increase the stable humus.
Important for gardening. It depends on the mineral composition. Vegetable plants grow well in neutral or slightly acidic soils.
There are also indicators of fertility:
- General acidity.
- Current acidity.
- Cation exchange.
- Requirement for liming.
- Saturation with bases.
- Organic content.
- Macronutrient content.
Fertility is also affected by the “soil density” indicator. High values lead to deterioration air regime, difficult mobilization of nutrients, insufficient root growth. Low density retards the growth of the root system due to voids and leads to increased evaporation of moisture.
Currently, there are fertilizers and additives, as well as various procedures to improve the quality of the fertile layer. But the earth needs to rest. Remember this!
The upper fertile layer of the lithosphere, which has the properties of both living and inanimate nature, is called soil.
Loose and fertile layer of soil
This natural element is formed with the participation of living organisms. The surface layers of rock forges act as the initial substrate from which different types of soils are formed under the influence of plants, animals and microorganisms, as well as climate, topography and humans. Soil formation occurred over thousands of years. At the beginning of the process, bare stones and rocks were colonized by microorganisms. By consuming carbon dioxide, water vapor, nitrogen from atmospheric air and mineral compounds from rocks, microorganisms produced organic acids. Over time, these chemical compounds changed the composition of the rocks, which lost their strength, which led to the loosening of the surface layer. The next stage of soil formation is the settlement of lichens on such rocks. These organisms are not demanding of water and food; they consistently continued to destroy rocks, while at the same time enriching them with organic material. In the process of joint work of microbes and lichens, rocks were transformed into an environment suitable for the development of plants and animal habitats. The final stage of soil formation from the original substrate occurs due to the vital activity of higher plants and animals.
Dead organic material in soil is home to many bacteria and fungi. In the process of their life activity, they destructure organic compounds and mineralize them with the formation of complex stable organic substances, which are soil humus. In the soil, primary minerals decompose with the formation of clay secondary minerals. Thus, the cycle of substances occurs in the soil.
Soil structure
Related materials:
Internal structure of the Earth
Earth's crust
Development of the earth's crust
Movement of the earth's crust
Everything on the COUNTRY LIFE website on the topic Soil fertility
We are used to accepting soil, without which plants and people could not exist as a matter of course.
Fertile soil layer
But it took nature millions of years to create the familiar priming. Initially, the earth was only rock, which over time was eroded and crushed by rain and minerals. The remains of emerging plants were gradually added to it, which were introduced into soil humus (organic matter). Dead wood, dying plants and fallen leaves have been adding to the topsoil (topsoil) for millions of years and improving its composition and structure. Mechanical and chemical composition soil is not the same on the surface of the earth, which is also due to geological reasons.
Soil: composition, properties, structure
The basis of any soil is sand, clay and silt, and soil structure and properties for agriculture determines the proportion in which these three components are presented. Structural soil has better air and water permeability, retains heat, moisture and nutrients.
Sandy soils They pass water well, warm up faster in the spring and freeze in the winter. Thanks to its sandy soil structure almost do not retain moisture and useful substances and are considered poor.
Clay soils may contribute to water stagnation and are slow to respond to change seasons(they take longer to warm up in the spring and do not freeze longer with the onset of cold weather). Structure clay soils allows them, however, to retain fertilizers and nutrients, ensuring high fertility. Often clay soils have a strictly acid-neutral reaction.
Silty soils in their pure form they are quite rare, for example, where there used to be a river bed. According to their own properties of silty soils similar to sandy ones, but contain a fairly high percentage of nutrients.
Loam contains all three elements (sand, clay and silt) in more or less equal proportions. Loam considered the most harmonious, easy to process and fertile soil.
Rocky soils provide excellent drainage, which, however, makes them most vulnerable during dry periods.
Calcareous soils They are characterized by a high content of calcium salts (lime) and have an alkaline reaction. By properties calcareous soils They look like sand and are very poor in nutrients.
Peaty soils consist of plant residues and have an acid reaction. Peat It is capable of being saturated with water, like a sponge, and retains moisture well at the roots of plants, but is poor in useful substances. Meet peaty soils where there used to be swamps. High acidity of peaty soil may contribute to magnesium deficiency and fungal diseases (e.g. clubroot cruciferous).
Soil composition: how to determine
Location on. Moisten the area soil using a watering can. See how quickly the water disappears from the surface soil. In almost a second, water seeps through rocky or sandy soil. Wet peaty soil also readily accepts additional water. On a surface clay soil the water will stay longer.
Now take a handful of soaked soil, squeeze it in your fist, and then see what it looks like. Sandy or rocky soil will fall apart into grains and slip through your fingers. Clay soil will leave a slippery feeling, stick together and remain in the hand in the form of a lump. Silty and loamy soils feel a little soapy and silky, however, they do not stick together as easily as clay soil. Peaty soil When clenched into a fist, it feels like a sponge.
At home. Add a heaping tablespoon soil from the site into a glass of clean water, stir and leave alone for a couple of hours. Now let's look at the result. Loamy soil will leave almost clean water in a glass with layered sediment at the bottom (see photo above). Sandy and rocky soil leave clean water in a glass with sediment of sand or pebbles. Calcareous soil will leave cloudy grayish water in the glass and the residue in the form of whitish grains. Peaty soil will leave somewhat cloudy water with some sediment at the bottom and a thick layer of light, thin fragments floating on the surface. Clay and silt soils will leave muddy water with a thin sediment.
Soil acidity
In respect of acidity (pH level), soils are (weakly) acidic, neutral or (weakly) alkaline. Neutral is the level Soil pH 6.5 – 7.0, most garden plants(including vegetables) prefers it for successful growth and development. Level Soil pH between 4.0 and 6.5 indicates acidic soil, and between 7.0 and 9.0 – by alkaline soil(the scale, in fact, also has extreme values, from 1 to 14, but they are actually not encountered by European gardeners). Knowledge soil acidity necessary for the right choice plants.
Reducing soil acidity achieved by adding lime to the soil. For increasing soil acidity organic conditioners are used, see below. Oxidation alkaline soil- the process is quite expensive, so in areas with alkaline soil Grow acidophilus in tubs and containers filled with acidic soil in bags from the garden center.
How to determine the acidity of the soil (soil) on the site
Method 1. Buy a special simple device for testing soil acidity (pH tester) at the garden center and take measurements. See photo above.
Method 2. Observe which plants grow especially well in your area, garden and vegetable garden. For example, heathers (Eric heather, Scottish heather, blueberry, cranberry and other 'bog' berry crops), rhododendrons, violets, witch hazel, camellia, knotweed (polygonum) and other acidophiles indicate acidic soil. Tar, henbane, anagallis, jasmine, saxifrage, oxalis, nightshade, carnation, as well as thriving lilac, weigela and jasmine indicate increased levels of lime in the soil.
Method 3. Put some soil into a container with vinegar. If foam appears on the surface (you may also hear the typical sound of foam forming), then the soil contains lime in significant quantities.
How to improve the soil. Increasing soil fertility
Improve the structure and properties of the soil on the site can be done using coarse organic materials that should be worked (dig) into the soil or simply spread over the surface of the soil in a 10-centimeter layer as mulch at least twice a year. TO improving soil fertility substances include organic fertilizers, etc. soil conditioners. ABOUTorganic fertilizers and soil conditioners glue structureless particles into small lumps, creating free space between them.
To improve soil structure and fertility, use :
- Well-rotted manure (better horse than cow) with straw. Manure is good for poor soils (rocky, sandy), enriching them and promoting the retention of moisture and nutrients at the roots of plants. Never apply manure fresh!
- Garden compost. Like manure garden compost better suited for enriching and improving the structure of poor soils.
- Mushroom compost. It usually contains rotted horse manure, peat and lime. Mushroom compost is good to use where neutral soils need to be given a slightly alkaline reaction, for example under tomatoes.
- Leaf humus. Excellent for conditioning, mulching and acidifying the soil in which moisture-loving acidophiles (plants for acidic soils).
- Peat. In fact, it does not contain useful substances, decomposes quickly and has an acidic reaction.
- Wood shavings and sawdust. Same as leaf humus. See above.
- Bird feathers. Rich in phosphorus, therefore suitable for application to soil for winter, as well as where root crops (potatoes,
- Shredded tree bark well suited for clay soils, improving their water permeability and making them more structured and lighter. The bark is also often used as mulch due to its beautiful appearance and valuable qualities
Apply soil conditioners at the same time as (or instead of) applying organic fertilizer. It is better to dig up empty areas of soil that are being prepared for planting, adding conditioners and fertilizers a couple of months before planting. Areas of soil occupied by plants are enriched with a layer of mulch made from conditioning organic materials with fertilizers at the very beginning of the season and at the end of the season.
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The soil
The upper fertile layer of the lithosphere, which has the properties of both living and inanimate nature, is called soil. This natural element is formed with the participation of living organisms. The surface layers of rock forges act as the initial substrate from which different types of soils are formed under the influence of plants, animals and microorganisms, as well as climate, topography and humans. Soil formation occurred over thousands of years. At the beginning of the process, bare stones and rocks were colonized by microorganisms. By consuming carbon dioxide, water vapor, nitrogen from atmospheric air and mineral compounds from rocks, microorganisms produced organic acids. Over time, these chemical compounds changed the composition of the rocks, which lost their strength, which led to the loosening of the surface layer. The next stage of soil formation is the settlement of lichens on such rocks. These organisms are not demanding of water and food; they consistently continued to destroy rocks, while at the same time enriching them with organic material. In the process of joint work of microbes and lichens, rocks were transformed into an environment suitable for the development of plants and animal habitats. The final stage of soil formation from the original substrate occurs due to the vital activity of higher plants and animals.
During the life of plants, absorption occurs from the atmosphere. carbon dioxide, and from the soil minerals and water with the subsequent formation of organic matter. After the plants die, the soil is enriched with organic material. The next link in food chain are animals that eat plants or their remains. Animal excrement and their carcasses also end up in the soil layer after death.
Dead organic material in soil is home to many bacteria and fungi.
Soil science - soil science
In the process of their life activity, they destructure organic compounds and mineralize them with the formation of complex stable organic substances, which are soil humus. In the soil, primary minerals decompose with the formation of clay secondary minerals. Thus, the cycle of substances occurs in the soil.
Soil moisture capacity and moisture permeability
Soil is characterized by moisture capacity - the ability to retain water, and moisture permeability - the ability to pass water. So, if there is a lot of sand in the soil, it retains water less well and, accordingly, has low moisture capacity. Soil with a high clay content, on the contrary, has high moisture capacity, as it retains more water. Thus, moisture is retained better in loose soils than in dense ones.
Moisture permeability is ensured by the presence of numerous small pores in the soil - capillaries. Water moves along them up, down and to the sides. The more capillaries in the soil, the higher its moisture permeability, and the faster the process of moisture evaporation occurs. Sandy soils have high moisture permeability, while clayey soils have low moisture permeability. When loosening the soil, the capillaries are destroyed, due to which the evaporation of water slows down and moisture is retained in the soil.
Based on characteristics such as acidity, acidic, neutral and alkaline soils are distinguished. For better growth plants are suitable neutral soils. On agricultural land acidic soils usually lime, and gypsum is added to alkaline ones.
Soil structure
Structure different types soils are different. Based on their mechanical composition, soils are divided into clayey, loamy, sandy, and sandy loam. The structure contains lumps of various shapes and sizes. Most suitable for growing cultivated plants chernozems having a granular or fine-lumpy structure. They contain about 30% humus. The content of a large amount of humus is a sign of soil fertility. In addition to chernozems, there are the following types soils: tundra, sod-podzolic, podzolic, gray soil, chestnut, yellow soil and red soil.
Related materials:
Internal structure of the Earth
Earth's crust
Development of the earth's crust
Movement of the earth's crust
Soil, its composition and structure
Soil is the surface layer of the Earth's lithosphere, which has fertility and is a multifunctional heterogeneous open four-phase (solid, liquid, gaseous phases and living organisms) structural system formed as a result of the weathering of rocks and the vital activity of organisms. Soil consists of soil horizons that make up the soil cover:
A – humus; B – mineral soil; C – unaltered soil material.
Figure 26 – Soil horizons
Chemical properties of soils. Each soil consists of organic, mineral and organomineral complex compounds. The main source of mineral compounds in soils are soil-forming rocks. Mineral substance makes up 80-90% of the total weight of the soil.
Organic compounds in the soil are formed as a result of the vital activity of plants, animals and microorganisms. During the process of soil formation, organic matter accumulates on the soil surface and in its upper horizons. The different ratios of the processes of entry of plant and animal residues into the soil and the processes of their transformation, as well as the different intensity of these processes, lead to the fact that the nature of the horizons for the accumulation of organic matter is very diverse.
Next important characteristic chemical properties soils is the degree of their acidity. It is determined in suspensions obtained by shaking soils with water (actual acidity) or KCl solution (exchangeable acidity), and is expressed in pH units. Based on the degree of acidity, acidic, neutral and alkaline soils are distinguished. Depending on the degree of acidity, the need for soil liming or gypsum and the application rates of lime and gypsum are determined.
One of the most important aspects of soil formation is the formation of soil colloids and the formation of a soil absorption complex capable of retaining cations of calcium, magnesium, sodium, potassium, ammonium, aluminum, iron and hydrogen in an exchangeable and non-exchangeable state.
The total amount of absorbed bases Ca**, Mg**, Na*, K*, NH4 is called the sum of absorbed bases. This value is expressed in milligram equivalents per 100 g of soil (mg-eq per 100 g of soil). The total amount of all exchangeable cations is called absorption capacity or exchange capacity and is also expressed in milligram equivalents per 100 g of soil. The absorption of anions by soils - Cl'1, NO'3, SO'4, PO'4, OH' - has the same characteristics.
The presence of absorbed hydrogen and aluminum cations in the composition determines the hydrolytic acidity of soils, the value of which is also expressed in mEq per 100 g of soil. The ratio of the sum of absorbed bases to the sum of absorbed bases plus hydrolytic acidity, expressed as a percentage, is called the degree of soil saturation with bases or saturation. Based on the degree of soil saturation with bases, the issue of soil need for liming is decided. required quantities lime and the forms of application of mineral fertilizers.
The main components of the mineral part of soils are SiO2 - silicon oxide (silica, silica) and R2O3 - sesquioxides.
Top fertile layer of soil
By changes in their content in soil profiles formed on homogeneous, non-layered rocks, one can judge the presence or absence of differentiation of the soil profile. This can be traced both by changes in the absolute content of oxides in different soil horizons (%SiO2, %R2O3) and by changes in the molecular ratios of SiO2: R2O3.
The natural fertility of soils is assessed by the amount of mobile (available for plant nutrition) compounds of nitrogen, phosphorus, and potassium. The content of these compounds is expressed in milligrams per 100 g of dry soil. Based on data on the content of mobile compounds of nitrogen, phosphorus, and potassium, the application rates of mineral fertilizers - ammonia nitrogen, potassium and phosphorus fertilizers - are determined.
In the southern and southeastern regions of our country, water-soluble salts of mineral acids, such as coal (Na2CO3, CaCO3, MgCO3, NaHCO3), hydrochloric (NaCl, CaCl2, MgCl2), sulfuric (Na2SO4, CaSO4, MgSO4) often accumulate in soils. ) and etc.
According to the degree of solubility in water, simple salts are divided into slightly, moderately and easily soluble. Slightly soluble salts in soils are MgCO3 and CaCO3 - calcium and magnesium carbonates, moderately soluble salt - CaSO4 2H2O - gypsum, the remaining salts are easily soluble. Easily soluble salts in concentrations greater than 0.25% are toxic to plants.
Typically, in the profile of non-saline soils, salts are distributed according to their solubility. Easily soluble salts are carried beyond the soil profile, moderately soluble salt - gypsum appears at a considerable depth (150-200 cm), and slightly soluble salts - carbonates - lie slightly higher along the profile.
The content of carbonates in soils is also a diagnostic feature. In the field, the depth of carbonate deposits invisible to the eye is determined by an elementary chemical reaction. A few drops of diluted mineral acid are applied to a small soil sample. Usually 5-10% hydrochloric acid is used. If carbonates are present in the soil, a reaction occurs between them and the acid with the release of carbon dioxide bubbles, the so-called boiling of the soil occurs. With a low carbonate content, only slight crackling is noted.
What is soil? This is the uppermost solid layer of the earth's crust on which plants live and develop. Soil is the basic condition for plant life - a source of water and essential nutrients.
To successfully engage in gardening, horticulture and floriculture, you need to understand the structure of the soil - after all, it can be successfully cultivated. This means, if necessary, we can change the composition of the soil, adapting it to the life of our plants.
Soil layers
The soil consists of four layers.
Wet soil layer
This is the surface layer of soil, it is only 3-7 centimeters thick. The moistened layer is dark in color. Vigorous biological activity occurs in this layer - after all, most soil organisms live here.
Humus layer of soil
The humus layer is thicker than the moistened layer - approximately 10-30 centimeters. It is humus that is the basis of plant fertility. When the thickness of the humus layer is 30 cm and above, the soil is considered very fertile.
This layer is also inhabited by organisms - they process plant residues into mineral components, which in turn dissolve in groundwater ah, and then they are absorbed by the roots of plants.
Preferential layer
The presoil layer is also called mineral. A huge amount of nutrients is concentrated in this layer, but the biological activity here is not at all great. However, the mineral layer also contains soil organisms that process nutrients into a form suitable for further consumption by plants.
Source rocks
The source rock layer is not biologically active. It is quite fragile - if it is not protected by previous layers, it becomes thinner very quickly, as it is susceptible to leaching and weathering.
Mechanical composition of the soil
And what do the soil layers themselves consist of? They have four components: organic and inorganic solids, water and air.
Solid inorganic particles
Solid inorganic particles in soil include sand, stone and clay. Clay is a key component of soil because it can bind the soil and hold water and dissolved nutrients.
The space between solid soil particles is called pores. The pores perform a capillary role, delivering water to the roots of plants, as well as a drainage role, removing excess liquid, avoiding its stagnation.
Particulate matter
The organic part of the soil is humus (humus) and soil fauna.
Soil bacteria and other organisms absorb plant residues and organic waste, process and decompose them, resulting in the release of simple mineral compounds (primarily nitrogen) necessary for plant nutrition. This process of decomposition of organic matter in the soil by bacteria is called humification.
Humus is the most significant part soil:
Humus is “responsible” for converting any components found in the soil into a form available for plant nutrition.
In its natural state, humus is the soil's immune system. It improves plant health and increases their resistance to pathogens.
Humus creates an optimal loose soil structure in which all processes - oxygen and water exchange - are stabilized.
Soils rich in humus retain heat and warm up faster.
According to the degree of humus content, soils are divided into:
poor humus (less than 1% humus),
moderately humus (1-2%),
medium humus (2-3%),
humus (more than 3%).
Only humus soils are suitable for agricultural needs.
However, it should be clarified that if the soil is not properly cultivated and over-fertilized for many years, the biological activity of the soil fauna is significantly reduced. Then the amount of humus can remain high, but the soil becomes unsuitable for planting and not fertile.
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Soil water
Soil water is not just a pure liquid, it is nutrient solution, which contains organic and inorganic substances characteristic of soil. Water enters the soil through precipitation, from the air, from groundwater, and also through irrigation (if we are talking about soils used by humans).
Plants receive nutrition through soil water.
Different types of soil have different abilities to absorb and retain moisture.
Sandy soils absorb water best, but they also retain it poorly - because the distance between particles (pores) in such soils is greatest.
Clay soils do not absorb water well and do not remove water well - due to their hard structure and minimal distances between solid particles.
The best soils in terms of structure are mixed humus soils, in which the structure is most balanced, so water is well absorbed, retained and carried to the roots of plants.
Soil air
Soil air is also contained between soil solids, along with water. It is needed to ensure the respiration of soil organisms and plant roots. Unlike the above-ground parts of plants, roots absorb oxygen and produce carbon dioxide. For this reason, there is more carbon dioxide in soil air compared to atmospheric air.
To provide plant roots with oxygen, loosen the soil. If there is not enough oxygen in the soil air, the growth of the plant root system slows down, and metabolism is also disrupted - the plant cannot fully absorb water and absorb nutrients. In addition, when there is a lack of oxygen in the soil, instead of the process of humification, the process of rotting occurs.
This explains the fact that even in seemingly well-moistened and nutritious soil, plants begin to feel depressed - they do not have enough oxygen for proper nutrition and health.
Home Gardening How to prepare the soil and area for planting potatoes
How to prepare the soil and area for planting potatoes
Preparation seat for potatoes. To properly prepare the soil for potato beds, you need to know its composition. IN middle lane it can be from heavy clayey to light sandy.
The depth of the fertile layer ranges from 10 to 30 cm. The color of the soil also differs from each other. Moreover, the darker they are, the more fertile.
Under the fertile layer, as a rule, lies a compacted podzol. You should dig and plow the soil only to the depth of the dark layer, trying not to turn the podzol inside out.
Digging or plowing Chernozem, floodplain and loamy soils are best carried out in the fall at full depth, adding 6-8 kg of organic fertilizers per 1 m of fertilizers.
Of the minerals, in the fall they produce phosphorus-potassium (30-45 g of superphosphate and 12-18 g of potassium sulfate). They are easily fixed by soil particles and are poorly washed out.
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Spring plot harrow or loosen the ground with a rake. When the soil is ripe, that is, it dries well and falls into small pieces in the hand, it is dug up or plowed, but to a shallower depth than in the fall (12-15 cm), and nitrogen fertilizer is applied (18 g/m2 ammonium nitrate).
After plowing, the area is leveled rakes or harrows. This concludes the preparation of the soil for planting.
Is it possible not to stretch all this work over two seasons, but to do it in the spring before planting?
In principle it is possible. But then from every hundred square meters you will not get 20-30 kg of potatoes. This is how to prepare a plot for planting potatoes in normal years, when sufficient precipitation falls in autumn and winter and the soil becomes compacted by spring.
If there was little snow and the soil was not compacted, then in the spring there is no need to dig it up, just harrow it and apply nitrogen fertilizers. Then, when the ground at a depth of 10 cm reaches 7-8 degrees, plant.
Unlike heavy ones, light sandy loam and sandy soils are dug up not in the fall, but in the spring, at the same time all fertilizers are applied. On average, 8-10 kg of rotted manure, 30 g of ammonium nitrate, 45 g of granulated superphosphate, 25 g of potassium sulfate are sufficient per 1 m2.
If the area allocated for potatoes suffers from waterlogging, then to remove excess water, drainage channels with a depth of 50-60 cm are made around it. If groundwater is close, channels are also installed in the middle of the area with a depth of approximately 30 cm.
On peaty boggy soils Potatoes can be planted only after they have been cultivated. This is not an easy matter. To drain groundwater, drainage is arranged here using drainage pipes or they dig grooves with a slope at the depth of the water so that its excess falls into the water intake (sump).
In addition, the soil is sanded. Usually, per 1 m2 of area, a bucket of coarse sand is added with mineral fertilizers(15-20 g of ammonium nitrate, 30-40 g of granulated superphosphate and 25-30 g of potassium sulfate) and another bucket of clay and rotted manure or compost.
However It is better to avoid growing potatoes on toffee-marsh soils, since the tubers here are obtained with worse taste and low starch content.
1. Soil is a special natural formation; the most superficial layer of the earth that is fertile. The founder of soil science, the outstanding Russian scientist V.V. Dokuchaev, established that the main types of soils on the globe are distributed zonally. Soil types are distinguished on the basis of their fertility, structure, mechanical composition, etc. The most fertile soil layer is the top layer, since humus is formed in it.
Soil types in Russia. Tundra-gley soils are common in the north. Low-power, low humus content, waterlogged, low oxygen content.
Under coniferous forests in areas of excess moisture, podzolic ones are formed, and under mixed ones - soddy-podzolic soils. Precipitation washes the soil and carries nutrients from the top layer to the bottom. The upper part of the soil takes on the color of ash. Poor in humus and mineral elements. They occupy more than half of the country's territory. Fertility podzolic soils increases to the south. Under deciduous forests, fairly fertile gray forest soils are formed (more plant litter, less intensive leaching).
To the south, in the zone of forest-steppes and steppes, chernozems are formed - the most fertile soils. A lot of humus accumulates from the remains of vegetation, and there is practically no leaching regime. The humus content in chernozem can reach 6-10% or more. The thickness of the humus horizon can reach 60-100 cm. They have a granular structure. Less than 10% of the territory is occupied by chernozem.
In drier climates, chestnut soils are formed. The humus content in them is less, as the vegetation cover becomes more sparse.
In desert areas with poor vegetation, brown semi-desert soils - gray soils - are formed. Contains little humus. Often salted.
The variety of soil types and features of their distribution are reflected on soil maps.
2. Population growth is an increase in its number. It can occur due to natural increase (the excess of the birth rate over the death rate) and due to mechanical increase (relocation or mechanical movement of the population). They are interconnected.
Natural increase varies in different parts of the country. It is connected with the socio-economic situation in the region, with the age structure of the population, with traditions. Thus, the peoples of the North Caucasus and some peoples of the Volga region are traditionally characterized by large families, which increases natural increase population. In the Non-Black Earth Region, natural growth is small, since many elderly and old people live here. Young people are leaving here. To the regions of Siberia, Far East During their development, a large number of young people arrived. This led to an increase in population. At the same time, natural growth also increased, as young people started families and many children were born. The age structure of the population has become characterized by a predominance of youth and children.
Population growth varies between cities and rural areas. In big cities there are many families with 1-2 children or no children at all. In rural areas (if there are young people there) more families with 2-3 children
