Brown soils: characteristics and conditions of formation, composition and properties

Formation conditions, composition, soil properties are important characteristics that must be taken into account in agriculture. Brown, humus-rich soils are considered fertile. Such lands are characterized by a loose structure, contain a variety of nutrients. Brown soil easily absorbs and retains moisture well, easy to cultivate.

Formation conditions

The main places for the formation of brown soils are foothill and mountainous regions, which are characterized by a temperate warm climate with hot, dry summers and wet, warm winters. Most often found in the flat areas of the Eastern Caucasus, in the North-West.Soils are formed under conditions of significant moisture in the autumn-winter-spring period.

Soil humus is formed due to the vegetation cover of dry forests (hornbeam, beech, maple, xerophytic oaks, tree juniper, walnut). The main source of organic matter in the soil is the grass cover that develops under the rarefied crowns of trees.

Genesis

The main process of soil formation is sod, associated primarily with the vital activity of herbaceous vegetation. Simultaneously with the soddy process, internal claying of the soil (the formation of clay materials) occurs.

It is thanks to herbaceous crops and the non-leaching type of water regime that humus accumulates. The earth acquires a lumpy-granular structure, showing water-physical and chemical qualities favorable for the development of plants. The top layer of soil accumulates nitrogen and ash substances necessary for the full growth of crops.

Profile structure and classification

Brown soils are heterogeneous. In the soil profile, several horizons can be conditionally distinguished due to the color classification:

• humus horizon (thickness - 30-50 cm) has a dark brown tint, low density, high biogenicity. It is characterized by a granular-cloddy structure containing plant roots;
• transitional humus/metamorphic horizon (thickness - 15-20 cm) is distinguished by brown color, walnut-lumpy structure. Many vertical long roots grow through the layer;
• The carbonate horizon of light brown or pale-brown hues is distinguished by a massive or small-blocky structure.

Naturally, there is no clear division into horizons in nature - the transitions are smooth and not clearly expressed.

Composition and properties

Due to the high content of humus (4-7%), brown soils are highly fertile. Soil properties: loose structure, saturation with mineral elements, good moisture capacity and water permeability. To prevent the compaction of the humus horizon, the method of deep loosening of the soil is used. At the same time, the depth of soil wetting increases, water and air permeability improves.

According to their characteristics, brown lands are suitable for growing valuable heat-loving crops (grapes, fruit crops). To increase productivity, the soil is fertilized with both organic matter and mineral additives (nitrogen, phosphorus mixtures).

When processing brown soils, the preservation and increase of their fertility are of great importance. Therefore, attention is paid to the prevention of water and wind erosion. Preventive measures: strip distribution of crops, round slopes are fenced with tree and shrub plantings, terraced slopes are also practiced. Periodic sowing of perennial grasses and green manure is recommended.

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