Sod-podzolic soils: characteristics and conditions of formation, fertility and vegetation

On the territory of Russia there are soils of different types, with their own structure, properties, level of fertility, which are influenced by formation factors. Consider the characteristics of soddy-podzolic soils, how they are formed, mechanical composition and structure, humus content. What properties do these soils have, classification, processing and application rules, vegetation characteristic of these soils.

What are sod-podzolic soils

The geographical position of soddy-podzolic soils is the southern part of the forest zone of the East European Plain and the West Siberian.This is about half of the territory of Belarus, 15% of the territory of Russia and 12% of the territory of Ukraine (northwest). Soddy-podzolic soils are formed in the natural zone of deciduous forests.

Location also explains the climatic conditions in which soils are formed and located. They are formed in areas where groundwater is deep, on rocks of different mechanical composition. A moderately humid and warm climate, the processes of turfing and podzolization, which take place simultaneously, take part in the formation. Climatic conditions and formation processes determine the characteristics of soddy-podzolic soils.

The theory of the formation of these soils

The structure of the soil profile of sod-podzolic soils is as follows: the top layer is forest litter (sod) 3-5 cm thick, under it is a humus-eluvial horizon of a characteristic gray color. It is followed by a podzolic or eluvial unstructured or weakly structured horizon resembling ash in color.This feature distinguishes soils of this type from all others.

The podzolic layer is whitish, 15-20 cm thick. Even lower is a brown or reddish-brown layer, which passes into the parent rock, from which soil formation began. The humus content is quite high - 3-7%, according to this indicator, soddy-podzolic soils are in first place among podzolic soils.

According to the level of podzolization, soils are divided into slightly podzolic, medium podzolic and strongly podzolic. Conditions of soil formation, humidity and temperature, vegetation cover, different activity of microorganisms also determine the different content of humus in the upper horizon; if humus is 1-2%, then the soils are slightly humus, if 2-4%, then medium-humus, if more than 4%, then high-humus.

The mechanical composition of soils of this type is different, they are formed on clays and heavy loams, loesses, sandy loams and sands, moraine and loess-like loams.

Structure and properties

The properties of soils of this type depend on how pronounced the processes of podzolization and sodding are, on the thickness of the corresponding horizons. In general, soddy-podzolic soils are not very fertile, only the top layer is rather humus-rich, moisture-intensive, and more structured. Fertility increases with cultivation. Economic soddy-podzolic soils have different characteristics and even profile structure.

Uncultivated soils, which are common in forests, contain few nutrients, have an acidic and strongly acidic reaction, are slightly saturated with bases (50-70%), humus consists mainly of fulvic acids, the structure is not water-resistant, can swim after precipitation . Plowed and cultivated soddy-podzolic lands have a thickness of the arable layer of 30-40 cm, contain more than 3% of humus.They have a finely lumpy structure, almost neutral reaction, saturation with bases reaches 80-90%.

Classification

Soddy-podzolic soils are divided into typical and gley. The former occupy almost 1.5% in Russia, the latter - 0.1%.

Typical

Located in the southern taiga and forest-steppe, formed on loose sandy loamy soils and sands, under pine forests. Humus horizon 3-15 cm thick, podzolic - 2-30 cm. The reaction of the soil is acidic or strongly acidic, the earth is not saturated with bases. The amount of humus varies from 0.5 to 5%, on average 1-1.5%, consists of fulvic compounds. Typical soils are mostly structureless, have poor water retention but good water permeability.

Gley

They are located in the southern taiga, in depressions or on flat plains with poor drainage and temporary stagnation of moisture on the surface. The formation of gley soils takes place under mixed forests with moss-herbaceous vegetation, often in waterlogged conditions. The underlying rocks are of heavy composition. Profile: sod 5-6 cm thick, humus layer 10-20 cm thick, gray-steel shade, gleyish gray-whitish with rusty inclusions, after it a textured brown gleyed horizon with spots of gray and ocher color.

Gley soddy-podzolic soils are acidic or slightly acidic, in the upper layers they are not saturated with bases. Humus of fulvate type, percentage - 3-5%.

Processing

Increasing the fertility of this type of land is carried out using the following agricultural practices: liming to reduce acidity, applying increased doses of organic matter and mineral fertilizers, sowing and incorporating green manure.Fertility and returns are increased by the deepening of the arable layer, the regulation of the water regime. The complex of works leads to a noticeable change in soil regimes, morphological features that accompany soil cultivation.

Features of processing depend on the mechanical composition. Optimal moisture conditions for medium loamy soils. On clays, planted plants will suffer from an excess of moisture, on sandy ones - from a deficiency. For land with different mechanical composition, cultivation methods will be different, but the main one is the introduction of manure, compost, peat-and-dung mixtures in an average amount of 3 kg per square meter. m, in the first seasons - 4-6 kg each. Organics improve water properties, clay loosens, sandy makes more water-retaining.

Perennials (clover with cereals) or green manure grasses, the cut mass of which is laid on the soil surface, will be able to replace organic matter. After overheating and digging, organic matter remains in the ground, the volume of which is equivalent to 3-4 kg of good quality manure.

On land with a light composition, legumes and phacelia are sown mainly. Sowing is carried out after harvesting potatoes and early vegetables, mowed and buried in autumn. Green manures improve the structure of the soil, sandy ones make them coherent, clayey ones loosen.

If the arable land is no longer used, overgrown with forest, then the arable layer is gradually transformed into a 5-7 cm thick podzolic layer.

Application

Despite the fact that this type of land does not have the best physical properties and low fertility rates, it can be used in agriculture to grow crops. In the first place in economic use is the cultivation of cereals and the use of pastures for livestock and hayfields.

Then in economic activity the soil is used for planting potatoes, but in order to get a good harvest, it is necessary to pre-treat and fertilize the soil, reduce acidity.

Ornamental crops, fruits and vegetables grow on such land only with constant fertilization, liming, loosening. Root crops, radishes, lettuce, legumes, tomatoes, onions, cucumbers grow on soddy-podzolic soil after refining.

Plants

Vegetation on soils of this type is mainly represented by deciduous species: oak, linden, aspen, maple, birch, hazel, and spruce. Shrubs grow between the trees: buckthorn, hazel, euonymus, wild currant, viburnum. Despite the low fertility of the soils, grassy vegetation also grows on them.

Sod-podzolic soils are formed in a temperate climate in the territory of growth of deciduous forests.Their feature is the middle gray horizon that gives them their name. They are not particularly fertile, do not have good physical properties, but after cultivation they acquire properties valuable for agricultural use, allowing them to grow traditional crops and get a harvest.

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