What is soil: composition and properties, how it is formed and characteristics, its main part

The soil took many thousands of years to form. Initially, the planet had a mountainous landscape. However, under the influence of minerals, its geology changed. Gradually, the properties of the substance improved. This happened under the influence of plant residues, fallen leaves, microorganisms. So what does such a thing as soil mean? This term is understood as a natural body, which appears as a result of the interaction of organic and inorganic nature.

What is soil?

Soil is a natural body, which is formed as a result of the transformation of the surface layers of the Earth under the influence of soil-forming factors. It includes soil horizons that form a profile and is distinguished by its fertility.

Studying the composition of the soil is a special science - soil science. Soil is also mentioned in other disciplines - in biology, in geography, in soil science. The properties of the earth are of interest to agronomists and geologists.

History of the term

Before the works of Dokuchaev V.V., the soil was considered as a geological and agronomic concept:

1. In 1839, this term was understood as a rock in the form of a layer. It was called the bed or the sole.
2. In 1863, the following definition appeared in the dictionary of Dahl V.I.: soil - earth, foundation.
3. In 1882, this term began to refer to the top layer of the earth.

In 1883, the definition was created by the famous soil scientist VV Dokuchaev. He considered the soil as an independent natural body, which is formed under the influence of soil-forming factors. The scientist attributed soil, climate, vegetation, relief, age to them.He elaborated that soil is a function of parent rock, climate, and organisms times time.

Composition and properties

The soil includes several fragments that are in it in different proportions. These include solid, liquid, gaseous and living parts. The amount of organics and living organisms is reduced from the upper layers to the lower ones.

So, the earth contains the following parts:

1. Solid is the main part of the soil. Its basis is considered to be mineral components that have a lithogenic origin. These include fragments of primary minerals formed as a result of weathering of secondary ones. This part also includes organics, including plant and animal remains and special humus components.
2. Liquid - this part is also called soil solution. It is water that is present in the soil with gases and dissolved organic and mineral substances.The composition of soil moisture depends on the characteristics of the soil formation process, climatic factors, and plants. The soil solution is an important medium for moving chemicals and moisture to plants.
3. Gaseous - this part is also called soil air. It fills the pores of the soil that are not occupied by moisture. In total, the volume of land pores can reach 25-60% of the total. This composition is unstable. It often changes throughout the year and even the day. The penetration of air into the soil is of great importance for the root respiration of crops.
4. Alive - this part includes soil microorganisms and animals.

Specific education

The process of soil formation is divided into primary and anthropogenic. Initially, its structure includes humus and minerals. Then the voids are filled with air, and microorganisms settle there, which, after death, decompose and organically enrich the soil, improving its characteristics.

Anthropogenic process is a consequence of human activity. People are engaged in farming, growing various crops in the soil and adding fertilizers to it to increase yields.

Basic Features

The key property of the soil is fertility. It affects other parameters. These include the following:

1. Absorption capacity. Plants absorb nutrients from soil solutions. However, for this they must be unconcentrated. With an excess of s alts, the plants will starve.
2. Water permeability. Water enters the soil under gravity and surrounds its particles. In this case, the indicator depends on the structure of the soil. So, sands include large particles, and therefore water easily gets into them. At the same time, water is hardly absorbed into the clay elements.
3. Moisture capacity. The closer the moisture layer is to the soil particles, the more it is retained by the earth.
4. Air capacity. In dry land, air fills all wells. Part of the air attracts soil particles. It is called absorbed. In this case, the air that is in large pores is considered free. For the normal development of plants, the soil must be constantly ventilated. This helps restore oxygen supply.
5. Soil heat. Its soil receives from the sun's rays. There is also a small amount of heat emitted by internal structures.
6. Relative density. It can be used to determine the ratio of the mass of the solid phase of the soil to the mass of the same volume of water at a temperature of +4 degrees.
7. Porosity. This term is understood as the total volume of all pores between the solid particles of the earth.

Types of soil

The most common is the genetic classification of soils. According to this gradation, there are such types of land:

1. Normal - correspond to soil areas. Examples of such soils are gray, podzolic, desert-steppe.
2. Transitional - these include carbonate and bog soils.
3. Abnormal - this group includes ash, marsh, alluvial lands.

The following types of soils are distinguished by mechanical composition:

• sandstones - have a light and loose structure;
• sandy loam - also considered light, but contain a lot of clay components;
• alumina - are heavy soils dominated by silty rocks;
• loam - are considered the most optimal variety for gardens and orchards;
• calcareous - have a very poor composition;
• marshy - need careful cultivation.

The following types of soils are distinguished by organic composition:

• tundra - found in areas saturated with moisture;
• podzolic - concentrated in the forest zone;
• gray forest - include a lot of nutrients and a powerful humus layer;
• chernozem - ideal for agriculture;
• chestnut - are found in dry steppes and include little humus;
• brown - located in dry steppes and adjacent to chestnut;
• serozems - localized in the foothills and low-mountain areas;
• s alt licks, solonchaks, solod - do not have their own natural zone;
• red and yellow soils - found in humid subtropics.

Meaning in nature

Soil performs important functions in nature:

• stores energy - without it, plants cannot carry out the process of photosynthesis;
• affects the composition of the atmosphere and hydrosphere;
• regulates the density and productivity of living organisms;
• converts surface water to groundwater;
• is a source of substances for the formation of minerals;
• is a habitat;
• is a planetary membrane;
• protects the lithosphere from excessive erosion.

Soil is an important object that is of great importance for the normal course of natural processes and human activity. Soil formation depends on many factors that affect its properties.

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