To be specific, we will call the surface layer of soil the topmost, less than 5 cm layer of soil plus plant litter on it. We can say that this is a thin layer between heaven and earth, on their border.
The Importance of Topsoil
The surface layer of soil has an extremely large influence on the soil, on its root-inhabited part. If the surface layer is smooth and dense, then it warms up easily spring sun and frozen soil quickly thaws after a frosty winter. Moisture easily rises through capillaries from the depths of the soil to its very surface and evaporates. But it is enough to loosen the surface layer shallowly, about 5 cm, in order to destroy the capillaries at the very surface, and the moisture will be retained in the root layer and will water the plants even in the absence of rain for a long time. Oxygenated and warmed warm air the surface layer will create comfortable conditions for the breathing of plant roots and their development, for the development of soil microorganisms that have “frozen out” during the winter, various soil worms, and insects. However, if this continues for a long time, then the bare, uncovered soil, under the influence of wind, rain, and hot sun, gradually loses its fertility, its structure is destroyed, nutrients are decomposed or washed away.
But in natural conditions The surface layer of soil is naturally protected by plants and covered with plant litter - dead parts of plants and herbs. About the same thing happens in the root layer of the soil - dead roots different plants form "underground litter". Moistened and warmed litter with a lack of oxygen serves as food for various soil microorganisms, which decompose it to more simple connections, which partially, together with water, enter the root layer of the soil. Living plants also feed soil microorganisms with their root secretions.
Half-destroyed organic matter of litter and dead microorganisms, root secretions of living plants are used by the following (in a chain) soil microorganisms - while some (aerobic), in the presence of oxygen, continue to destroy it into even simpler compounds - nutrients absorbed by plants, while others (anaerobic) ), in conditions of lack of oxygen, they also use incoming organic matter for their needs. But how can both types of microorganisms exist simultaneously? To do this, anaerobic microorganisms produce a special glue - “fresh” humus. This humus glue is used by anaerobes to glue soil particles into lumps like grains - aggregates. It is inside these lumps of soil (aggregates) that anaerobes create comfortable conditions for themselves with a lack of oxygen. And oxygen lovers, supplying partially destroyed organic matter, live outside these soil grain aggregates. And the soil, as a result of such symbiosis, becomes granular (structural), i.e. "cultured" and fertile.
If you look at the topmost layer of soil in a meadow, you can see that it is heavily penetrated by superficial plant roots, which are often woven into dense turf. Moreover, the thinnest, absorbing roots tightly entwine the lumps of soil. This means that it is in them that plants receive the most nutrients. And this is where most microorganisms live. After all, living plants themselves are not parasites: they feed the soil microflora with their root secretions. And it is in the root layer that the granular structure of the soil appears. And this is where most humus is formed. From this observation, Academician Williams’ famous grass-field system for restoring soil fertility was born.
Forest litter and meadow turf
The influence of leaf litter in forests and meadow sod on the soil differs significantly. In forests, there is usually no black, humus-rich layer of soil under the forest floor. On the contrary, in steppes and meadows there is almost always a black, humus-rich layer of soil, or even black soil. What is the reason for such a big difference?
There is not too much difference, as it seems at first glance, in the composition of the litter: tree leaves in one case, and the remains of herbaceous, usually cereal plants, in the other. The absence of direct sunlight under the forest canopy and its presence all day in the steppes. Usually acidic leaching soil, especially in northern forests and carbonate, often salted soils in southern steppes with thick chernozem horizons.
C:N ratio (carbon: nitrogen)
If we say the same thing in other words, we get this: the ratio of carbon to nitrogen C:N in leaf litter of the forest floor is much higher than for residues herbaceous plants, therefore, forest litter is decomposed mainly by fungi, which process it into highly soluble fulvic acids, which, unlike humic acids, do not form humus. In addition, the decomposition of any leaves produces a lot of acids. Similar processes occur when acidic, unaerated peat is incorporated into the soil.
Unlike leaves, the C:N ratio for herbaceous plant residues (about 35-65) is much more favorable for many types of soil microorganisms, including soil bacteria that require nitrogen for development. In this case, humic acids are synthesized, forming humus.
Soil, acidity and calcium
The acidity of the soil itself has a very large influence on the predominant microflora: an acidic environment is more favorable for fungi, and a slightly acidic, neutral and slightly alkaline environment is more favorable for fungi. general case more favorable to soil bacteria, although there are also fungi that are resistant to such an environment. Neutral soil has a more diverse soil microflora, among which there are many species beneficial to plants. For most plants, neutral and slightly acidic soil reactions are also most favorable.
In addition to reducing soil acidity, calcium and magnesium form water-resistant compounds with humic acids and contribute to soil structuring. The best soil-forming rocks for the formation and fixation of humus are loams, especially carbonate loess, loess-like loams in black earth steppes.
Water meadows, top layer of settled silt
Since ancient times, the most successful and long-lasting farming has been in the flooded meadows of rivers. A small layer of fine particles of organic matter and clay covered the flooded meadows and the remains of plants on them after the flood. And it was these lands that could be used for centuries to conduct Agriculture without destroying their fertility.
Soil improvement
In addition to organic matter and moisture, the sun's rays intensively penetrate into the top layer of soil, the thermal regime improves, the diversity and number of microorganisms increases, which reduce the number of pathogens. However, some pathogens can survive on infected plant debris on the soil surface. However, when added to the top layer mineral fertilizers NP (nitrogen-phosphorus) or complete fertilizer, humus/compost, or even sprinkling infected plant debris with soil enhances biological activity and soil health from pests(completely suppresses them during the season). In this case, the decomposition and disinfection of infected plant residues occurs much faster than when they are plowed into the soil.
Revitalizing topsoil in spring
The surface layer of soil enriched with oxygen and warmed by the sun will create comfortable conditions for the development of soil microorganisms that have “frozen out” during the winter, among which there are many useful ones that improve the health of the soil and increase its fertility. But in the spring there are very few of them and they develop more slowly than harmful ones. Therefore, it will be useful to accelerate the development of beneficial microorganisms. To do this, you can use mulching with compost, manure humus, water the surface layer of soil with their infusions (warm infusions, warm water), infusions of cultures of beneficial microorganisms (bacillus hay, trichoderma, etc.). In my opinion, one should not refuse preparations of the so-called “EM - effective microorganisms” containing a complex of beneficial microorganisms. These are primarily “Shine”, “Baikal” and the like: Tamir, Vozrozhdenie, etc. Beneficial soil microorganisms will suppress pathogens of plant diseases and quickly start a chain of restoration of ecological balance (organic matter, microorganisms, worms and insects, etc.).
Worms and insects
The top layer of soil, organic residues, protects the soil from the action of wind, rain, and hot sun, which destroy the soil structure. A loose top layer with a large amount of organic matter stimulates the reproduction of soil insects and earthworms. Earthworms, with their moves, help improve the structure of the soil; in addition, they drag plant remains deep into the soil and bring to the surface heaps of earth from their esophagus - caprolites (the so-called vermicompost), containing many nutrients for plants and rich in beneficial soil microflora. The top layer of soil is home to many insects, many of which are useful (for example, predatory ground beetles) or are an important link in the ecological balance, including the most important food link for small animals and birds. Interestingly, some pests in moist soil rich in organic matter do not damage plants, but feed on soil organic matter (so-called “facultative” pests). An example is the wireworm (the larva of the click beetle), which is more aggressive in poor organic matter or dry soil.
Glade
excerpt from V. Grebennikov’s book “My World”
“Changes, of course, are happening, but now that this meadow has become almost exactly the same as it was before people, the changes are taking place slowly and unnoticeably, and only the experienced eye of an ecologist can detect them. Take, for example, the soil. Fat, rich black soil, disintegrating in the hand into weighty, durable, moist grains, like crumbly, but very dark buckwheat, - it continues to form here, unlike neighboring hayfields and especially arable lands, every year, every day and hour, except, of course, in winter. When the grass is not mowed, its dry remains lie right there and, with the assistance of rain and sun, bacteria and insects, ticks and other living creatures, turn into good humus. And in this fertile place, in the steppe corner between the pegs, the layer of fertile humus grows much faster than what happened in the treeless steppes - half a centimeter a year, or even a centimeter! The middle of the Glade - I specifically measure it - has risen by 14 centimeters over the past fifteen years, and all of it now looks elevated, high; this is especially noticeable late autumn or in early spring, when there is no foliage on the trees, and there is no snow in the Glade."
The fact that soil is a multi-layered cake has been known since school. To verify this, you need to conduct a small experiment.
A small hole half a meter deep is dug so that one of its walls is straight and strictly vertical. This is what will show you how many layers the soil on yours consists of. suburban area. And by removing the top layers of soil one by one, you can see with your own eyes what they consist of.
The top layers of soil are usually dark in color. This color comes from humus, which is rich in the top layer. Again, let us turn to the school curriculum and recall that humus is processed by microorganisms:
- Dead parts of plants;
- Remains of dead insects;
- Earthworms;
- Small animals.
It is the top layer that is considered the basis for the life and development of plants. Only the soil is suitable for cultivation, and only on it do plants grow. Although soil is considered one of the layers of the earth, it also consists of several layers. Of course, they are not so large, one might even say, quite small, but it is these layers that make it possible to grow on the ground the plants necessary for humans, which are included in their nutritious diet.
Soil layers
Terrain
There are two main layers of soil: the moistened layer and the humus layer. The first layer is biologically active because it contains the highest content of humus. And in color it is darker than all the others.
The humus layer is much thicker than the humid layer. Sometimes its thickness reaches 30-40 centimeters. If in your suburban area this layer has such dimensions, then you are lucky. This soil is classified as fertile. And rest assured, not only cucumbers and tomatoes will grow well here, but even exotic flowers and trees. It must be said that microorganisms live in this layer, which, like a processing factory, produce mineral substances, where the raw materials are the remains of plants and living organisms.
These minerals are a kind of food for plants, so they are absorbed by the roots. But before this, the process of their dissolution by groundwater occurs. This solution is absorbed by the roots of the plants. These top layers of soil are the most biologically active.
If you remove the top layers of soil, which were discussed above, then such land is generally not suitable for any cultivation.
The next layer, which is less active, is the mineral layer. Its builders call it the subsoil horizon. There is practically no humus here, but the content of minerals in a huge number. True, in this form, minerals are not suitable for plant nutrition, so here, too, processing is necessary, in which microorganisms must participate.
AND last layer– This is a layer of parent rocks. So to speak, this is an empty layer. Most often it is this that is washed out and eroded. These processes occur slowly but constantly.
Soil composition
Division into different soil layers
If we talk about soil as a multilayered mass, then it is necessary to talk about its composition. The basis of the entire mass is solid particles. They can be either organic or inorganic. Soil also contains air and water. The amount of water and air depends on the size of the particles and their density. If the space between the particles is large, then the air and water content is correspondingly greater.
Solid particles of inorganic origin include:
- Clay;
- Sand;
- Stone.
And here, as in everything in this world, it must be in certain proportions. For example, clay. This mineral substance has the ability to bind water and retain it in the soil. If there is not enough clay, then the water will quickly go down and join the groundwater. If the clay is more than normal, then soon a wetland will form on your site, which will have to be drained.
As mentioned above, it is humus or humus that particles of organic origin consist of. It is humus that determines the soil fertility indicator. It is he who will help you reap a wonderful harvest. True, there is one “but” here too. This is the mandatory presence of a sufficient amount of oxygen, which will help speed up the humification process. Otherwise, the usual process of rotting will take place.
True, the quantitative content of humus does not always contribute to soil fertility. Its biological state is also necessary here. Only the sum of two factors determines whether your plot will have a good harvest or not. You cannot add minerals to the soil uncontrollably; only a certain balance can make your garden bear fruit.
Now a little about water. The main purpose of water is to dissolve minerals, which form a kind of solution. It is this solution that is absorbed by the roots of the plants. Therefore one of the most important characteristics soil is to absorb and retain moisture.
But again, it is necessary to note that water, like everything else, must be in the soil in strictly a certain proportion. Therefore, soil drainage is considered one of the main elements that influence its fertility. Poor drainage leads to stagnation and excess water accumulation.
The soil is divided into several groups, which correspond to different structures and, accordingly, water conductivity. Eg, sandy soils They conduct water well, but their coarse-grained structure does not allow them to retain it. What can you say about clay soils. Clay is a poor conductor of water. In addition, as life shows, it is clay soils that often lead to waterlogging.
Water also acts as a kind of thermostat. The process of heating and cooling the soil occurs the slower the more more water contained in it. All avid gardeners know this.
Another factor in soil fertility is the sufficient oxygen content in it, which provides respiration for the root system of plants and microorganisms. If the upper part of the plants releases oxygen, then root system only carbon dioxide. Therefore the content carbon dioxide quite large in the soil.
Humus layer of soil for planting
Lack of oxygen in the soil leads to reduced plant growth, so the supply fresh air into the soil an essential component of fertility. We can summarize that sufficient soil moisture is not yet complete success in growing good harvest. Only the combination of all factors can create conditions that will have a positive impact on the productivity of your site.
If we talk about the top layers of soil as the foundation on which the Vacation home, then many factors will have to be taken into account. After all, different layers have different structures. Let's look at some options.
The most important indicator of soil for building a house is its sufficient strength and low compressibility coefficient. But not all soils have such indicators. Let's give examples.
On peat soils you will have to do a lot of work related to draining and strengthening the upper layers. Typically, houses on such soils are built on stilts. This is quite an expensive pleasure, but nothing can be done. All this work will still have to be carried out.
Availability groundwater in the upper layers it is a big problem. This will be especially noticeable in the spring, when the snow begins to melt and it rains. After winter cold the soil thaws, creating a large number of moisture. And this has a detrimental effect on the foundation. Therefore, it will be necessary to intensively carry out waterproofing work. Again financial expenses.
On soils containing large amounts of sand, it is also problematic to build a country house. Sand is a bad base. True, there are many methods for strengthening sandy soils. But this will again lead to unnecessary expenses. Money. There are, however, sandy soils that are quite dense and deep. You can easily build on these stone house, even two-story.
In the classification of soils, there are those that contain several main components at once. For example, sandy loam, in which the content of clay particles is 3-10%. Or loams with clay content in the range of 10-30%. Or loess soils, which differ from the above in the content of loam in the granular state. Although both of them belong to sandy soils.
All these types of soils are natural grounds for building the foundation of a country house. The last three can also be attributed to solid foundations if they are kept dry.
Structure of the top layer of the earth
In soils with weak soil layers it is necessary to carry out engineering work to strengthen these layers. There is quite a lot of experience here, and this does not cause problems today. Although it is not cheap.
The most ideal option for the base under the foundation - these are rocky soils that have the highest strength. In addition, they do not shrink, frost is not a problem for them, and water is the same. During floods, such soil is not washed away, which does not lead to displacement of the foundation itself.
But they have one drawback that will upset gardeners: a small layer of fertile soil. You will have to tinker for several years to plant a garden or vegetable garden on such a plot. But perseverance and work will grind everything down, as popular wisdom says.
Having examined all layers of soil in this article, we can draw a simple conclusion. Whatever the soil is on your site, do not be upset. We'll fix everything because modern technologies gone far. And with their help you can solve seemingly impossible tasks.
It took nature several billion years for the Earth’s soil to acquire the properties that allowed vegetation to appear on our planet. At first, instead of soil, there were only rocks, which, due to the influence of rain, wind, sun rays gradually began to crumble.
Soil destruction occurred in different ways: under the influence of the sun, wind and frost, rocks cracked, were ground with sand, and sea waves slowly but surely, they broke huge blocks into small stones. Finally, animals, plants and microorganisms made their contribution to the formation of soil, adding organic elements (humus), enriching the top layer of the earth with waste products and their residues. The decomposition of organic elements when interacting with oxygen led to various chemical processes as a result of which ash and nitrogen were formed, turning rocks into soil.
Soil is the modified loose upper layer of the earth's crust on which vegetation grows. It was formed as a result of the transformation of rocks under the influence of dead and living organisms, sunlight, precipitation and other processes due to which soil erosion occurred.
Due to this transformation of huge, hard rocks into a loose mass, the top layer of soil acquired an absorbent surface: the structure of the soil became porous and breathable. The main importance of soil is that, being penetrated by the roots of plants, it transfers to them all the nutrients necessary for growth, and combines two features necessary for the existence of plants - minerals and water.
Therefore, one of the main characteristics of the soil is a fertile layer of soil, which allows for the growth and development of plant organisms.
In order for a fertile layer of soil to form, the soil must contain a sufficient amount of nutrients and have the necessary supply of water, which would not allow plants to die. The value of land largely depends on its ability to deliver nutrients to the roots of plants and provide them with access to air and moisture (water in the soil is extremely important: nothing will grow if there is no liquid in the soil that will dissolve these substances).
The soil consists of several layers:
- The arable layer is the top layer of soil, the most fertile layer of soil, which contains the most humus;
- Subsoil - consists mainly of rock remains;
- The lowest layer of soil is called “bedrock.”
Soil acidity
A very serious factor that affects soil fertility is soil acidity - the presence of hydrogen ions in the soil solution. The acidity of the soil is increased if the pH is below seven, if it is higher it is alkaline, and if it is equal to seven it is neutral (the concentration of hydrogen ions (H+) and hydroxides (OH-) is the same).
A high level of acidity in the top layer of soil negatively affects plant growth, since it affects its characteristics (size and strength of soil particles), applied fertilizers, microflora and plant development. For example, increased acidity disrupts the structure of the soil, since beneficial bacteria cannot develop normally, and many nutrients (for example, phosphorus) become difficult to digest.
Too much high level acidity makes it possible for toxic solutions of iron, aluminum, manganese to accumulate in the soil, while the intake of potassium, nitrogen, magnesium, and calcium into the plant body decreases. The main feature high level acidity is the presence under the upper dark layer of earth of a light layer, the color of which resembles ash, and the closer this layer is to the surface, the more acidic the soil and the less calcium it contains.
Types of soil
Since absolutely all types of soil are formed from rocks, it is not surprising that the characteristics of the soil largely depend on chemical composition and physical characteristics of the parent rock (minerals, density, porosity, thermal conductivity).
Also, the characteristics of the soil are influenced by the exact conditions under which the soil was formed: precipitation, soil acidity, wind, wind speed, soil temperature and environment. Climate also has an indirect effect on the soil, since the life of flora and fauna directly depends on the temperature of the soil and the environment.
Soil types depend largely on the size and number of particles that are present in them. For example, damp and cold clay soils are formed by sand particles tightly adjacent to each other, loamy soil is a cross between clay and sand, and rocky soil contains a lot of pebbles.
But peat soil includes the remains of dead plants and contains very few solid particles. Any soil on which plant organisms grow has a very complex structure, since in addition to rocks it contains salts, living organisms (plants), and organic substances that were formed as a result of decay.
After the soil analysis has been done in different regions our planet, a classification of soils was created - a set of similar areas that had similar soil formation conditions. Soil classification has several directions: ecological-geographical, evolutionary-genetic.
In Russia, for example, the ecological-geographical classification of soils is mainly used, according to which the main types of soil are turf, forest, podzolic, chernozem, tundra, clayey, sandy, and steppe soils.
Chernozem
Chernozem, which has a lumpy or granular structure, is considered the most fertile soil (humus content is about 15%), characteristic of a temperate continental climate, in which dry and wet periods alternate, and above-zero temperatures predominate. Soil analysis showed that chernozem is rich in nitrogen, iron, sulfur, phosphorus, calcium and other elements necessary for the favorable functioning of plants. Chernozem soils are characterized by high water-air characteristics.
sandy lands
Sandy soil is characteristic of deserts and semi-deserts. It is a crumbly, granular, devoid of cohesion soil, in which the ratio of clay to sand is 1:30 or 1:50. It does not retain nutrients and moisture well, and due to the poor vegetation cover it is easily susceptible to wind and water erosion. Sandy soil also has its advantages: it does not become waterlogged, since water in the soil easily passes through the coarse-grained structure, air reaches the roots in sufficient quantities, and putrefactive bacteria do not survive in it.
Forest lands
Forest soils are characteristic of forests temperate zone northern hemisphere and their properties directly depend on the forests that grow in it and have a direct impact on the composition of the soil, its breathability, water and thermal regimes. For example, deciduous trees have a positive effect on forest soils: they enrich the soil with humus, ash, nitrogen, neutralize acidity, creating favorable conditions for the formation of beneficial microflora. But coniferous trees have an impact on forest soils Negative influence, forming podzolic soil.
Forest soils, no matter what trees grow on them, are fertile, since nitrogen and ash, which are found in fallen leaves and needles, return to the soil (this is their difference from field soil, where plant litter is often removed along with the harvest).
Clay soils
Clay soils contain about 40% clay and are moist, viscous, cold, sticky, heavy, but rich in minerals. Clay soil has the ability to retain water for a long time, slowly become saturated with it and very slowly let it pass into the lower layers.
Moisture also evaporates slowly, allowing plants growing here to suffer less from drought.
Properties clay soil do not allow the plant root system to develop normally, and therefore most of the nutrients remain unclaimed. In order to change the composition of the top layer of soil, it is necessary to apply organic fertilizers over several years.
Podzolic soil
Podzolic soils contain from 1 to 4% humus, which is why they are characterized grey colour. Podzolic soil is characterized by a very low content of nutrients, high acidity, and therefore it is infertile. Podzolic soils are usually formed near coniferous and mixed forests of the temperate zone, and their formation is strongly influenced by the predominance of precipitation over evaporation, low temperatures, reduced microbial activity, poor vegetation, which is why podzolic soils are characterized by low nitrogen and ash content (for example, soils of the taiga, Siberia, and the Far East).
To use podzolic soils in agricultural work, farmers need to make a lot of effort: add large doses of mineral and organic fertilizers, constantly adjust water regime, plow the ground.
Sod soil
Soddy soils are fertile and characterized by a low or neutral level of acidity, a high amount of humus (from 4 to 6%), and they also have soil properties such as water and air permeability.
Soddy soils are formed under developed grass cover, mainly in meadows. Soil analysis showed that the turf soil contains a large amount of magnesium, calcium, ash, and humus contains a lot of humic acids, which, upon reaction, form humates - insoluble salts that are directly involved in the formation of the lumpy-grained structure of the soil.
Tundra land
Tundra soils are poor in minerals and nutrients, very fresh and contain little salt. Due to low evaporation and frozen soil, tundra soils are characterized by high humidity, and due to the insufficient amount of vegetation and its slow humification - low humus content. Therefore, tundra soils contain a thin peaty layer in their upper layer.
The role of soil
The importance of soil in the life of our planet is difficult to overestimate, since it is an indispensable element of the earth’s crust, which ensures the existence of plant and animal organisms.
Since a large number of very different processes flow through the upper layer of the earth (among them the cycle of water and organic matter), it is a connecting link between the atmosphere, lithosphere and hydrosphere: it is in the upper layer of the earth that the earth is processed, decomposed and transformed. chemical compounds. For example, plants that grow in the soil, decomposing along with other organic substances, are transformed into minerals such as coal, gas, peat, and oil.
Equally important protective functions soil: the earth neutralizes substances found in it that are hazardous to life (this is especially important, since recently soil pollution has become catastrophic). First of all, these are toxic chemical compounds, radioactive substances, dangerous bacteria and viruses. The safety margin of the top layer of the earth has a limit, therefore, if soil pollution continues to increase, it will no longer cope with its protective functions.
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 has 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 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 soil is not a homogeneous structure. It consists of several soil-forming components. But the greatest difference is observed when you look at the soil in cross-section. The soil layers in the section are represented by different horizons.
What is a soil horizon? From a genetic point of view, the soil horizon is a certain layer, distinguished by its own color, density, structure and other qualities.
The horizons are located one above the other parallel to the soil surface and together make up the soil profile. The formation of soil horizons takes many years. The number of soil horizons, depending on the classification system, is 15-16 pieces.
Soil performs very important functions for plants. In fact, she is theirs digestive system— many soil microorganisms process organic and mineral substances, preparing them for plants. Plants themselves cannot perform such functions.
Plant roots receive water and oxygen through the soil. Soil keeps plants upright and protects their roots from pests and unfavorable climate conditions.
Of greatest interest is the top fertile layer of soil, also known as the upper soil horizon.
Topsoil is a complex of upper soil horizons that provide fertility. It consists of several horizons.
These are various animal remains and plant origin: grass, leaves, fungi, insects and other dead small organisms. Creates shelter for seeds and pre-root parts of plants.
This soil layer has a depth of up to twenty centimeters. Contains organic matter processed by insects and worms and particles of uneaten plants and animal organisms. This is the most valuable nutrient layer for plants.
Mineral layer
Source of minerals for plants. This layer is formed throughout for long years and contains mineral elements remaining in the process of complex long-term transformations of organic and inorganic matter. Contains dissolved gases, water, nitrogen, carbon and other essential components necessary for plants.
Humus layer
In this layer, biosynthesis processes from organic waste also occur, but due to specific conditions, these processes occur differently - not like in the upper layers. As a result of biosynthesis, flammable gases are formed in the humus layer, which are a source of energy and heat.
Subsoil layer
Consists of clay. Regulates the processes of exchange of moisture and gases between surface and deep soil layers.