The deciduous forest zone covers a wide strip of Eurasia and North America. Basically, these forests are in temperate climates with flushing aqua mode on the plains. In these forests, oaks and beeches, hornbeams and ash trees, lindens and maples, various herbaceous plants and shrubs are found. All this flora grows on ordinary gray soils and podzolic, brown and dark gray forest. Sometimes forests occur on highly fertile chernozems.
Brown soils of the forest are formed during the accumulation of humus and rotting plants. The main element is scorched leaves. The soil is enriched with various humic acids. The illuvial soil level is saturated with secondary minerals, which are formed as a result of chemical and biochemical processes. Earth of this type is highly saturated with organic matter. The composition of burozem is such a scheme:
- the first level is litter;
- the second - humus, lies 20-40 centimeters, has a gray-brown color;
- the third level is illuvial, bright brown in color, lies approximately 120 centimeters;
- the fourth is the level of parent rocks.
Brown soils of the forest have a fairly high fertility rate. A variety of tree species, types of shrubs and grasses can grow on them.
The forest is characterized by gray soils. They come in several subspecies:
- light gray - contain 1.5-5% humus in general, saturated with fulvic acids;
- forest gray - sufficiently enriched with humus up to 8% and humic acids in the soil;
- dark gray - soils with a high level of humus - 3.5-9%, containing fulvic acids and calcium neoplasms.
For gray soils, the forming rocks are loams, moraine deposits, loesses, clay. According to experts, gray soils formed as a result of degradation of chernozems. Soils are formed under the influence of sod processes and the small development of podzolic. The composition of gray soil is presented as follows:
- litter layer - up to 5 centimeters;
- humus layer - 15-30 centimeters, has a gray color;
- humus-eluvial light gray hue;
- eluvial-illuvial gray-brown color;
- horizon illuvial brown-brown;
- transition layer;
- parent rock.
In broad-leaved forests, fairly fertile soils — burozems and sulfur — occur, as well as other types. They are equally enriched in humus and acids, are formed on different rocks.