Soils are chestnut, their properties and classification

Chestnut trees are called soils, the condition of formation of which are dry steppes. What properties have chestnut soils, how they formed, where they are common, read in this article.

Where and how are chestnut soils formed?

The place of origin is dry steppes with arid climate, insufficient precipitation, high evaporation. Chestnut soils are formed under a thinned vegetation cover, so the sod process here is poorly developed in comparison with the chernozem zone. From the conditions of moistening depends on how weak or strong the sod process will be expressed.

Its more intensive manifestation is characterized by the northern regions of the zone where the most humus-rich soils are formed - dark chestnut soils. With the advance to the south, the dryness of the climate increases. There is a transition of these soils into chestnut soils, and then into light chestnut soils, the humus content of which is low, the thickness of the horizon is small.

If there is little precipitation and the soil is washed weakly, the salt products of soil formation are not able to penetrate deeply, so they remain on the surface. With intensive decomposition of vegetation along with such compounds as calcium, silicon, magnesium, alkali metals are also liberated in large quantities. Because of their presence in the soil begins to develop solonetsousness. An important feature of soil formation in the steppe zone with a dry climate is that the solonetsous process is superimposed on the turf.

Types of soil in dry steppes

• Chernozems are southern and ordinary.
• Dark chestnut.
• Chestnut.
• Light chestnut.

The chernozems and chestnut soils are a continuous strip stretching from the west to the Altai foothills. East of the Altai there are small isolated islets in the region of the basins, in the Selenga and East-Transbaikalian steppes. These soils have become widespread in the Caspian lowland and in Kazakhstan, in the area of small hills.

For comparison: chernozems occupy 8.5% of the territory of the Russian steppes, and chestnut soils - only 3. The main feature of chernozems is the high content of humus. Typical chernozems are characterized by a deep occurrence of groundwater. It is noteworthy that the upper strata of the soil are well sedimented by sediments, the lower one by groundwater, and between them is a dry horizon. It is these conditions that are suitable for the formation of chernozem and chestnut soils.

In each subtype of chestnut soils, depending on the thermal conditions, the following groups are distinguished: warm, moderate, deep-cold. In addition, within a separate subtype, the soil is divided into genera. This is common, solonetsous, alkaline-solonchak, residual-solonetzic, carbonate, carbonate-solonetzic. It should be noted that the chestnut soils of different genera have a different manifestation of signs of both solonetsousness and solonchakiness.

Soil dark chestnut

They are occupied by the northern part of the zone. Dark chestnut soils are characterized by a lumpy or lumpy granular structure of the humus horizon on virgin lands, and on arable soils it is dusty-lumpy. The occurrence of gypsum and readily soluble salts occurs at a depth of about two meters. Characteristic chestnut soil is impossible without a description of the thickness of the humus horizon. At this soil it reaches 50 centimeters. In solonetsous soils in the lower part, the humus horizon is more dense. This is explained by the fact that it is enriched with colloidal particles.

A lumpy and lumpy structure has dark chestnut soils. Their properties are more pronounced with increasing solonetsousness of the horizon. The structural faces have a lacquered brownish brown color. The genus of solonetsous dark chestnut soils is subdivided into the following species:

• Non-solitary ones. They absorb up to 3 percent sodium from the total absorption volume.
• Weakly solonetsous soils - 3-5 percent.
• Medium solonetzic - 5-10.
• Strongly solonetsous - 10-15.

Characteristics of dark chestnut soils

• Saline-solonchak Soils of dark color refer to strongly saline rocks. At a depth of one meter, the content of water-soluble salts increases.
• In the residual-solonetsous soils, the content of exchangeable sodium is imperceptible. Here solonetsousness is of a residual character.
• In solonetz-solodized soils, the upper or lower part of the humus horizon has indications of solodization, which are represented by siliceous powder on structural faces.

• Carbonate chestnut soils have an elevated carbonate content on the surface. The place of their formation is heavy rocks.
• The formation of carbonate-solonetsous soils occurs on saline rocks with a heavy mechanical composition. Soils have an increased density and a fractured addition of the profile. When they are wet, they begin to swell and stick.

Characteristics of chestnut soil

It is distinguished by the thickness of the humus horizon. In chestnut soils this figure is 30-40 centimeters. Most of the carbonates accumulate at a depth of 50 centimeters, gypsum - 170, and soluble in water salts - at a depth of two meters. These soils have the same generic features as those described above.

Soil light chestnut

The zone of their formation is the southern part of the dry steppes, occupied by wormwood and cereal plants. These soils are formed in a strongly arid climate. The thickness of the humus horizon is small - 25-30 centimeters. It differs in structureless composition and weak washing. Because of this, the carbonate layer lies close to the surface. The depth of the gypsum horizon is 1 meter 20 centimeters. In this soil, readily soluble salts accumulate in large quantities, so the signs of solonetsousness are everywhere. Not solonetsous chestnut soils can be found extremely rarely.

The upper horizon of this soil has a lighter color, its structure is loose. This is influenced by solodization. Light chestnut soils are divided by genera as well as others. Solonetsity and solonchakiness in light soils are more pronounced and are of zonal character.

Using

Soil steppes, especially dark chestnut, have sufficient nutrient reserves. It has high fertility. It grows wheat, millet, corn, sunflower, melons and horticultural crops. Yields are much higher if phosphorous, potash, nitrogen fertilizers are introduced into the soil and moisture is retained in it.

Chestnut soil without dark or light shades is more often used for hayfields, pastures, and grazing lands. But it is also suitable for the cultivation of the cultures described above. On light chestnut soils, different crops can be grown only with regular irrigation.

The solonetsous chestnut soils are characterized by unenviable fertility. Therefore, chemical and biological reclamation is used to increase it. Sometimes it is enough to plow the land deeply.

disadvantages

• Light chestnut, chestnut and solonetzic soils of the steppes have a humus layer of low power. This can not provide the root layer with normal conditions.
• The compacted horizon is relatively shallow. This violates the water regime of the soil and prevents the roots of plants from penetrating deeper.
• Solonets soils have an increased concentration of alkali, which causes the need to oxidize the soil before it is used.
• The soils of the steppes lack moisture and nutrients, especially light chestnut.

Man should help chestnut, low-power, malostructural and solonetzic soils to become powerful, rich in humus and nutrients. It is necessary to systematically irrigate the soil to replenish its water reserve, introduce organic and mineral fertilizers into it, and observe the latest techniques of agricultural technology.