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 types of them exist?
What is soil?
V. I. Dahl in his dictionary indicates the genesis of this term from the Old Russian word to rest (lie down). What is soil in a scientific context?
Soil (or soil) is a specific natural formation, the upper layer of the hard shell of the planet (lithosphere), which is distinguished by its systemic structure. The study of this unique natural body is engaged in a separate science - soil science. The father of this discipline can be considered the great Russian researcher Vasily Dokuchaev. In the second half of the XIX century, it was he who put a lot of effort into answering the question as accurately as possible: “What is the soil?”
It is difficult to imagine that a single soil, with the same properties, stretched for several tens of kilometers. Scientists identify 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 humus that determines the key property of the soil - its fertility. It should not be assumed that the soil is an exclusively “dead” and abiotic formation. It is home to many living organisms - from bacteria to ticks and earthworms. Even the representatives of the family of mammals (for example, a mole) live in the soil environment.
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 basic properties of the soil are:
- water permeability (soil is a porous formation that passes water well, however this property depends on the structure and mechanical composition of a particular soil);
- moisture capacity (on the other hand, the soil is capable of retaining a certain amount of moisture, thereby feeding the roots of the plants);
- water loss (ability of the soil to raise 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 vital activity. With the help of rational methods of tillage, 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, exactly the “bridge” that provides 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 processing, excessive deforestation, etc.
Soil formation process
As mentioned above, the soil is formed as a result of two processes: weathering of the rock and activity of organisms.
The factors of soil formation include the following:
- climatic features of the region;
- maternal 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 the soil).
Climatic processes influence the formation of the soil directly, determining in many respects its regime and structure, as well as indirectly (through vegetation and animal organisms).
Main soil types and zones
Soils, like many other components of nature, are subject to geographical (latitudinal) zonality. So, the following (basic) soils can be distinguished:
- Krasnozem and yellowing - types of soils that are formed in a subtropical and tropical climate, in conditions of high moisture.
- Podzolic soils are poor soils that form under coniferous and mixed forests. These soils are common in temperate latitudes of Europe and North America.
- Gray-brown soil - a special type of soil, which is formed under the deserts and semi-deserts. They are characterized by high salinity, common in Central Asia.
- Chernozem - 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, rocky, sandy-clayey, etc.
Clay soil contains in its composition about 40-60% clay. It has specific properties: viscosity, dampness and plasticity. The permeability of such a soil is usually not very high. That is why clay soil is extremely rarely completely dry.
The 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 geographic shell. 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.