Soil is a special natural formation that serves as the main resource for the development of agriculture in any country. What are the main factors of soil formation, and what kinds of soils exist?
What is the soil?
VI Dal in his dictionary indicates the genesis of the term from the Old Russian word to rest (lie). What is the soil in a scientific context?
Soil (or soil) is a specific natural formation, the upper layer of the solid shell of the planet (lithosphere), which is characterized by a systemic structure. The study of this unique natural body is carried out by a separate science - soil science. The father of this discipline is the great Russian explorer Vasily Dokuchaev. In the second half of the XIX century it was he who made a lot of efforts in order to answer the question as precisely as possible: "What is the soil?"
It is difficult to imagine that for several tens of kilometers one soil with the same properties would extend. Scientists distinguish several types of soils, each of which has its own set of features. However, any of them is formed under the influence of two main processes:
- Weathering of rocks.
- Activity of living organisms.
The internal structure of any soil includes several components. It:
- mineral part (parent rock);
- organic part (or humus);
- soil air;
- alive organisms;
- neoplasms and inclusions.
It is the humus that determines the key property of the soil - its fertility. It should not be assumed that the soil - formation is exclusively "dead" and abiotic. It is home to many living organisms - from bacteria to mites and earthworms. Even the representatives of the Mammal family live in the soil environment (for example, a mole).
Properties and meaning in nature
It is impossible to correctly answer the question, what is soil without telling about its main properties. It is equally important to know about its role in nature and human life.
So, the main properties of the soil are:
- water permeability (soil is a porous formation that passes water well, but this property depends on the structure and texture of a particular soil);
- moisture capacity (on the other hand, the soil is capable of retaining a certain amount of moisture, thus feeding the roots of plants);
- water yield (the ability of the soil to lift water up the soil pores).
However, the most important (and unique) property of this natural formation is its fertility - the ability to saturate the roots of plants with nutrients and water, which, in turn, ensures their livelihoods. With the help of rational methods of cultivation of land, a person can increase the fertility of a particular soil.
The role and place of soil in nature is difficult to overestimate. After all, it is, in fact, precisely the "bridge" that ensures the interaction of all four shells of the Earth - the lithosphere, hydrosphere, atmosphere and biosphere.
Soil is the most important economic resource, which is the basis for the production of almost all food products. Unfortunately, about a third of all the fertile lands of the planet are at the stage of degradation due to their environmental pollution, improper handling, excessive deforestation, etc.
The process of soil formation
As already mentioned above, the soil is formed as a result of two processes: the weathering of the rock and the life of organisms.
The factors of soil formation include the following:
- climatic features of the region;
- parent rock;
- biota (plants and animals);
- human activity.
However, the main factor of soil formation is the climate of the territory. It affects not only the formation of soils, but also their distribution over the territory of the planet (latitudinal zonality of soils).
Climatic processes affect the formation of the soil directly, determining in many ways its mode and structure, as well as indirectly (through vegetation and animal organisms).
Primary soil types and zones
Soils, like many other components of nature, are subject to geographical (latitudinal) zoning. So, it is possible to single out the following (basic) soils:
- Krasnozem and zheltozem - types of soils, formed in the subtropical and tropical climate, in conditions of increased moisture.
- Podzolic soils are poor soils that form under coniferous and mixed forests. These soils are common in the temperate latitudes of Europe and North America.
- Gray-brown soils are a special type of soil, which is formed under deserts and semi-deserts. They are characterized by great salinity, are widespread in Central Asia.
- Chernozem is the most fertile type of soil. Formed in the steppe and forest-steppe zone of Eurasia and America.
Depending on the mineral composition and structure, the soil can also be: clayey, sandy, stony, sandy-clay, etc.
Clay soil contains about 40-60% of clay. It has specific properties: viscosity, dampness and ductility. The water permeability of such a soil is usually not very high. That is why clay soil is extremely rarely completely dry.
Soil is a special natural body, with certain properties and structure. However, the main, key feature is its fertility. The properties of the soil determine its very important place in the geographical envelope. After all, it provides the interaction of all its structural elements. In addition, it is an important economic resource on which the food security of any country in the world depends.