Podzolic soils of Russia are considered one of the most common in the middle lane. They are considered the most infertile. These soils are structureless, characterized by high acidity, as well as the presence of a podzolic horizon. Often they form under the canopy of coniferous forests.
Soddy soils are also common in the middle zone of the country. They are formed under the influence of grassy vegetation. Among the features of soddy soils, an elevated humus content , a practical or partial absence of a podzol, and a lumpy-granular structure are distinguished. As a rule, they are highly fertile.
Sod-podzolic soils are the main in the non-chernozem zone of the country. They include the upper sod and lower podzolic layer. These soils are characterized by low fertility, low (from 0.5 to 2.5%) humus content and acid reaction (pH 4-5) of the soil solution. In addition, the humus horizon has a small thickness (ten to twenty centimeters).
As a rule, sod-podzolic soils have a humus-rich top layer. Moreover, on carbonate moist rocks, the processes of decomposition of plants and their transformation into humus proceed much faster.
Sod-podzolic soils are characterized by an extremely low content of nitrogen and phosphorus (in the form that plants absorb). On soils characterized by a light composition (sandy and sandy), there is a lack of potassium.
All sod-podzolic soils contain very little iodine, zinc, copper. Along with this, they are distinguished by an excess of manganese. To increase the fertility of these lands, it is necessary to regulate the water-air regime, especially in excessively wet areas. The fertile layer is increased by applying organic fertilizers to the soil. Acidity is reduced by liming.
Sod-podzolic soil type is distributed mainly in the northern half of the non-chernozem zone. Their formation does not occur under the forest, but mainly in the meadows. In these territories, as a result of the death of herbs, a perennial grass felt appears on the surface, and root remains are located in the thickness. In this case, the roots often interweave with the upper part of the plants. As a result, a single layer is formed. It has a large number of plant residues.
The presence of a whitish layer is characteristic of the sod-podzolic type of soil. Its structure and color resembles furnace ash. In slightly podzolic soils, the thickness of the interlayer is a few centimeters, and the soil stratum itself is of the order of twenty to twenty-five centimeters. In this regard, such lands do not need a radical improvement.
The reverse situation is with strongly podzolic soils. The use of such lands is possible only after work to improve them. In addition to the low content of nutrient components, the absence of non-capillary duty cycle, as well as the unfavorable water-air regime, greasy clay can occur at a shallow depth (about thirty to forty centimeters), and under it there is a thin, but solid and dense “flagstone”, consisting mainly of iron oxides. In this regard, sod-podzolic soil must be dug to a depth of at least forty - forty-five centimeters, or very wide pits should be dug out at least fifty centimeters deep.
Due to the fact that some of the dying plants remain in the thickness of the earth, where air access is difficult, bacterial decomposition and subsequent penetration of organics into deeper layers occurs only partially. In the process of decay, humic acids are formed, which pass (as a result of some chemical reactions) into humins and subsequently take part in the formation of fresh humus and lumpy structure of the upper soil layer.