Soil composition

Classification of soils is based on the principleconsidering the soil as an independent special body of nature, which can be placed on a par with minerals, animals and plants. This method of classification is based on the properties and features of the origin of soils. The first to divide the soils according to the genetic feature of Dokuchaev V.

The main feature by which division occurs is the type of soils. This classification means soil that has arisen under the same conditions and has similar properties and structure.

Among the most famous we can distinguishthe following types of soils: podzolic, red earth, chernozems, solonchaks and others. The types of soils are further subdivided into subtypes, genera, species and varieties, and into categories.

Subtypes reflect the distinctive features of the soilprofile. Here the role plays, how continental the climate and thermal conditions of the given latitudinal zone are. Subtypes are intermediate links between types.

Further separation takes place according to genera and speciessoils. The most common genera of soils are ordinary, solonetsous, residual-alkaline, solonchakous, quartz-sandy and contact-gley, residual-carbonate, residual-arid.

Each kind of soil has an additional division intokinds. The species reflects how pronounced the process of soil formation, characteristic of a specific soil type. In turn, several species are distinguished among the species. These are related to the same type of soil, the difference of which is only their mechanical composition. These include clayey and loamy, sandy and sandy loamy. Division by category means that the soils are of the same species and mechanical composition, but the parent material is of different origin.

Different properties directly depend on what is the mechanical composition of the soil.

This value is determined by the particle ratioSoils of different sizes and expressed in percent. Cartilage, pebbles and stones have poor water permeability, formed from fragments of rocks and primary materials. Sand has the property of rapidly flowing water, since it almost consists of some primary minerals. In the dust there are secondary minerals swelling from the water - this phenomenon causes such property of soils as stickiness and plasticity. The composition of soil from silt includes secondary minerals from clay. They, very much swelling in the water, then do not miss almost no water, no air.

If the particles decrease in size, the process of weathering and the subsequent formation of secondary minerals begins - these are iron, aluminum, aluminosilicate and carbonate salts of Ca, K, Mg.

The size of the mechanical elements affects their chemical composition and physical properties. And so, knowing the composition of the soil, you can find out what properties it possesses.

The upper soil horizons and soil-forming rocks of it, depending on the mechanical composition, are divided into:

  • Sandy:

- connected;

- loose.

  • Sandy loam.
  • Clayey:

- heavy;

- the average;

- The lungs.

  • Loamy:

- heavy;

- the average;

- The lungs.

Different mechanical composition of the soil, differingthe content of physical clay, affects such a property as plasticity. At various its parameters, the earth can roll down into a ball or into a cord. This helps determine the mechanical composition of the soil in the field. Its name, as a rule, reflects its mechanical composition. For example, ordinary chernozem heavy-loamy.

Agronomical properties of soils also depend on theirmechanical composition. It is easy to handle sandy loam and sand, which is why they were called lungs. And, on the contrary, loamy and argillaceous have earned a reputation for being difficult because of difficulties in agronomic processing. However, they contain more nutrients and humus, in contrast to sand and sandy loams, and therefore are considered more fertile.