Zonal soil types: characteristics and in what direction the change occurs

Soil is a special natural body that is formed on the earth's surface as a result of the interaction of animate and inanimate nature. Fertility is considered a key characteristic of the soil. It is associated with the presence of humus or humus in the composition. At the same time, scientists identify several zonal soil types that differ significantly in this parameter.

What are zonal soil types and their classification?

More than a hundred years ago, the famous soil scientist Dokuchaev VV noticed that the main types of soil are placed in accordance with the special principle of latitudinal zonality.Each type of soil has certain characteristics. They differ in composition and degree of fertility. This factor should definitely be taken into account when engaging in agriculture.

Tundra gley

The soils of the Far North are frozen almost all year round. For a short period, they thaw literally a few tens of centimeters. This provokes waterlogging of the soil. A special thin type of soil is formed there. They are known as tundra-gley and have specific characteristics.

Under the upper horizon there is a bluish-gray or greenish-gray layer. Sometimes it contains rusty spots - a gley horizon. It is also simply referred to as gley. It is formed during prolonged or constant waterlogging. Also, this leads to a lack of oxygen in the soil structure. Under such conditions, manganese and iron compounds are in the ferrous form.This is the color of the horizon.

Tundra-gley soil types contain a minimal amount of nutrients. The volume of humus in their structure is 73 tons per 1 hectare. This type of soil is characterized by low microbiological activity.

Podzolic soils

Such soils are formed under coniferous forests. They are located on the East European Plain. Also, this type of soil is found in the West Siberian Plain. In these places, the amount of precipitation exceeds the process of evaporation.

As a result, there is a pronounced washing of the soil, which leads to the formation of a clarified leaching horizon A2. All mineral elements and organic matter from this part of the soil move into the groundwater.

Part of the compounds accumulates in horizon B, which has a compacted and rusty tone. In the A1 humus horizon, soil massiveness and humus reserves increase gradually. It goes from north to south.

The amount of humus in this type of soil is 99 tons per 1 hectare. They include a small amount of nutrients, but contain a lot of moisture. With proper fertilization and quality care, such soil can produce a good harvest.

Chernozems

These are the most humus-rich soils in Russia. They form under herbaceous plants and are found in the steppe and forest-steppe zones. In the structure of chernozems there is a humus horizon of great massiveness - 0.4-0.8 meters. It is characterized by a black color.

Above the horizon is steppe felt, which includes traces of herbaceous plants. The transitional horizon B is below the humus horizon. It is characterized by a heterogeneous black-brown color.

Horizon B gradually transforms into soil-forming rock - C. These zones are characterized by the same evaporation from the surface and the annual amount of precipitation. However, it weakens from north to south. Therefore, in conditions of insufficient saturation of the soil, they cannot be washed.

This soil includes many valuable components. The content of humus in chernozems reaches 426-709 tons per 1 hectare. However, they do not always contain a sufficient amount of moisture. It is on chernozems that the bulk of wheat is grown.They are also suitable for growing sugar beet, sunflower, corn. With proper irrigation or artificial moisture retention, black soils produce excellent yields.

In what direction is soil change happening

The law of horizontal soil zonality was formulated by VV Dokuchaev. Its essence lies in the fact that important soil-forming factors naturally change from north to south. Therefore, zonal soil types consistently replace each other. Thus, they are placed on the earth's surface in the form of latitudinal bands.

Each natural area is characterized by certain types of soil. However, their latitudinal location can be disturbed by differences in relief and parent rocks. Also, this parameter is affected by the proximity of the ocean.

The main zonal soil types and their location are shown in the table:

Soil typeFeaturesArctic desertsArctic Characterized by scarcity and low power.TundraTundra-gleyDifferent in low power, include a minimum amount nutrients. Such soils are of low agricultural value. they are characterized by a poor humus horizon. At the same time, podzolic soils are distinguished by a powerful underlying horizon, which is similar in color to ash. Abundant precipitation wash the upper horizon, removing humus from it.Mixed forests Sod-podzolicBroadleaf forests Forest grayStiff-leaved evergreen forests and shrubs Brown, taupeForest-steppe and steppe Dry steppesSemi-deserts BrownDeserts Grey-brownSavannas Red-brown

Natural area



		They are considered moderately fertile. At the same time, the level of humus gradually increases. This type of soil is characterized by significant leaching.
		They are distinguished by a powerful humus horizon and are considered quite fertile. Significant plant litter is characteristic of this zone.
		The level of organic matter in the upper horizon is more than 5%.
	Chernozems	Considered the most fertile types of soil. They are characterized by significant plant litter and weak washing. Chernozems are distinguished by a powerful humus horizon.
	Chestnut	Thickness parameters of the humus horizon reach 20-50 centimeters. Such lands are considered the most fertile.
		Contain a minimal amount of humus.
		Include little humus.
		Considered relatively fertile. During the rainy period, there is a significant leaching of nutrients. In the dry period, incomplete decomposition of plant litter occurs.
	Red, red-yellow ferralitic	Different low fertility. Soils contain iron compounds. That is why they are distinguished by a reddish tint. It also contains aluminum compounds. Organic matter in the soil is not completely decomposed. In addition, this type of soil is characterized by strong leaching.

Zonal soil types are diverse. They are characterized by different composition and properties. Depending on this, the degree of soil fertility also changes. These features should definitely be taken into account by people who are engaged in agriculture.