Permafrost-taiga soils: formation conditions, fertility and geographical location

The formation of permafrost-taiga soils occurs in regions where permafrost is observed. Frozen horizons are present in the soil profile, which prevents it from being washed out by water. Therefore, the removal of organic matter and mineral elements is difficult. A distinctive feature of such soil is considered to be low fertility. Therefore, it is almost never used for agricultural purposes.

Characteristic

The mineralogical structure of this type of soil today is poorly studied. Under the influence of constant winds and frosts, a low content of highly dispersed minerals is observed. Their structure is largely influenced by soil-forming rocks.

The peculiarity of such soils is high acidity. At the same time, as it deepens, its severity decreases. The division according to the gross chemical structure is considered weak. But along the entire soil profile, there is a noticeable accumulation of iron oxides, which are quite mobile. This is strongly expressed in the upper part of the horizon. The content of this element in such layers reaches 20-25%.

Its accumulation is carried out in accordance with a certain scheme. So, with constant weathering, free iron is formed in the soil structure. In the autumn-winter period, it rushes up with water flows and, under the influence of freezing, is fixed in the upper layers.

Lower temperature parameters in the upper soil structures are associated with climate features. It is characterized by a low thickness of snow cover and low air temperature. In summer, the current of moisture is eliminated downward, which leads to low evaporation of the soil.

At the same time, dissolved organic substances move down with water, but with the advent of autumn, they again rise up. When the ascending and descending currents coincide, the process of soil formation of permafrost-taiga soils with significant ferruginization parameters occurs.

If downward flows prevail, podzolization of the soil begins. In this case, iron and alkalis are washed out, which provokes a decrease in fertility parameters. When plowing, the water-chemical properties of the soil deteriorate. The formation of this type of land is mainly carried out under the deciduous taiga. Their main features are shown in the table:

Profile Reaction Humus content in percent Humidity factor 1

Uniform in terms of gross composition
Slightly acidic, sometimes slightly alkaline
3 -5

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On which continents are located

The geographical location of the taiga permafrost zones falls on the northern parts of the Trans-Baikal region. Such types of soil are found in the Chukotka Autonomous Region, in Yakutia. There are such lands in the Kolyma region. They are also localized in the forest zone of Alaska.

Typical zones of such soils are located in the area of the Canadian Shield. There are such lands on the Labrador Peninsula. In Asia, the lower boundary of such lands corresponds to 50 degrees north latitude. In North America and Alaska, they are localized at 60 degrees.

In Eurasia, such soil occupies approximately 4% of the territory, which corresponds to 2230 thousand square kilometers. In North America, such land accounts for 2.4% of the territory. This corresponds to 590 thousand square kilometers.

Gleying soils occupy 200 million hectares in the climatic zones of Russia. In Eurasia, this type of soil is localized in zones of discontinuous and continuous permafrost. In North America, it is found in island permafrost zones with low temperatures.

Formation conditions

These soils are formed in permafrost regions. In these zones, negative temperatures are observed most of the year - for 7-8 months. In the summer, the upper ground structures thaw, but with the advent of winter, they freeze again.

The formation of permafrost-taiga soils is associated precisely with harsh climatic conditions. Frosts during the entire growing season make it difficult for plants to absorb valuable elements, provoking a slowdown in their growth and development.The process of decomposition of plant residues is also disrupted. This causes disruption of the normal biological cycle of substances and leads to the formation of forest floor.

Permafrost, which persists for hundreds of years, affects the thermal and water regimes. It affects the course of physical and chemical processes in the soil and the formation of a microrelief. In zones where the permafrost is presented in the form of a dense ice crust, excessive wetting of soil horizons is observed. There is also their gleying. As a result of these processes, humic elements accumulate in subpermafrost zones.

A distinctive feature of the permafrost-continental regions is that even in August the temperature parameters of the soil are much lower than the heating of the air.The same applies to the general value of average daily temperatures. This is similar to the frozen soils located in the Arctic Circle. Rainfall in such regions is 250-600 millimeters.

Permafrost-taiga soil types occupy impressive natural areas. Often they are located in hard-to-reach places. Within their limits, moisture indicators and features of rocks that affect soil formation change greatly.

Permafrost-taiga soils are a large category of soil, which is very problematic to divide into subspecies. This is due to the small amount of research done.

Morphological structure of the profile

For such soils, a relatively simple profile structure is characteristic. It is weakly differentiated in terms of horizons. Pronounced gleying and peatiness are considered characteristic features of this type of soil.

As a rule, a brownish-buffy or red-rusty horizon is formed under a layer of peat litter. It can be sandy or loamy. This element is characterized by a gravel structure.

Horizon C is not always highlighted. The thickness parameters of the fine-earth strata are 80-90 centimeters, and the seasonal thawing of soils reaches 80-120 centimeters. The entire profile is acidic.

Main soil-forming processes

The key processes of soil formation include the following:

• litter formation;
• cryoturbation;
• cryogenic structuring;
• coarse humus-accumulative process;
• gleying.

Economic use

Most of these soil types are not suitable for agricultural practice. However, some areas can be used for growing plants. This is done after reclamation, which provides deeper thawing in summer.

Plots of distribution of such soils today are often used as bases for fur farming. Also in these areas are actively creating hunting and fishing facilities. Mosses, lichens and shrubs mainly grow on such soils. Therefore, they are used as pastures for deer.

Besides this, in these regions there are many deciduous forests of valuable species. They are raw materials for the woodworking industry and construction.

Improvement

The cold climate and the close location of the icy permafrost make the soil unsuitable for agricultural use. The meadow-chernozem permafrost soils of Central Yakutia are considered an exception.

When properly used in this region, it is possible to achieve high yields of fodder plants. To improve the structure of the soil, the application of mineral and organic top dressings and full irrigation are required.

Vegetation

Permafrost-taiga soils are not as fertile as podzolic or chernozem soils. These zones are dominated by phytocenosis, consisting of heather, blue lingonberry and other types of shrubs. Also here there are such plants as undersized varieties of birch, alder. In addition, dwarf willows and dwarf pines grow in such places.

Permafrost-taiga soil types are characterized by low fertility, so they are rarely used in agriculture. At the same time, certain soil improvement measures make it possible in some regions to use them for growing certain crops.

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