The term black earth imply highly fertile black soil, rich in humus. This soil has a crumbly structure and is formed in temperate climatic zone forest, clay or loamy soil. Scientists say that the black soil is considered the best agricultural soil. Large deposits of such lands are in the forest-steppe or steppe zone under perennial grasses. Now in these places to grow grain and industrial crops.
Large areas of fertile lands in Ukraine, China, several countries in Western Europe to the United States and Canada. In Russia, this soil is present on the territory of the North Caucasus, the Volga region, Western Siberia. Black soil is formed by the alternation of the moisture from draining. The soil formed on clay and loess loam at a mean annual temperature of up to +3...+8 degrees and rainfall of 400-600 millimeters. Black soils mostly occur in the plains, though their deposits are found in the ravines and gullies.
The main feature of black soil is considered a good aeration, the ability of the soil to allow air and water through its structure. In addition, this soil has a granular structure, it contains a lot of calcium, iron and other trace elements. Mass fraction of calcium depending on the type of soil varies from 70 to 90 percent. In most cases, the soil has a neutral or close to neutral the acid reaction.
Value of topsoil are considered to be high rates of fertility. The soil has a natural formation. The amount of humus in the upper layers of the soil reaches 15 %. This means that such lands are almost do not need additional nutrients, which are made by organic or mineral fertilizers. Experienced gardeners say that culture with weak roots need a loose soil. In this case the topsoil should be diluted with peat or sand.
In nature there are the following types of topsoil:
- Ashed. Such soil is formed in deciduous forests;
- Leached. Formed in forest-steppe zone under meadow grasses;
- Typical Chernozem formed under cereal crops or perennial grasses in the forest;
- Ordinary Chernozem is formed under grasses. These soils occur in the Northern part of the steppe.
Through high fertility black soils are considered the most valuable land in the world. This soil is suitable for growing vegetable garden plants, fruit trees, berries. Such soil has been successfully used for the breakdown of lawns, in the cultivation of clay land, create flower beds and other purposes.