Meadow-chernozem soil is common on terraced plains and in lowlands, which are located in forest-steppe and steppe zones. It is also found in undergrowth - in the area of low river terraces. This soil is also present on deluvial plumes. The base rocks are colluvium of chalk marls and loess-like loamy soils. The upper layers of this soil are characterized by a granular structure.
Composition and properties of meadow-chernozem soil
Such soils have unique characteristics. There is a lot of humus in the upper soil horizons.As the soil deepens, its volume decreases. Humic acids are considered the main part of the soil. In terms of the amount and accumulation of humus, this type of soil can even exceed chernozems.
The reaction of the soil is close to neutral. Moreover, it is characterized by a fairly high cation exchange capacity. Per 100 grams of soil it can reach 45 micromoles. In this case, the volume of magnesium accounts for up to 30-50% of the total amount of exchangeable bases.
This type of soil resembles black soil. Its distinctive feature is considered to be the close location of groundwater to the surface and the gleying of the subhumus horizon and the top of the soil-forming rock from a depth of 1.2-1.5 meters.
Among meadow-chernozem soil types, saline varieties are often observed, which is associated with the presence of saline groundwater. The northern forest-steppe is characterized by soda salinity, while the southern one is characterized by sulfate salinity. In the steppe zone there is a chloride-sulfate type.
Formation conditions
This type of soil is mainly common in forest-steppe. However, sometimes it is observed in the steppe and deciduous forest zones. The largest massifs are localized in intermountain lowlands located in Transbaikalia. They are also located in the West Siberian Lowland. This type is also found in the Oka-Don lowland.
Such soils are considered semi-hydromorphic substitutes for chernozem.However, their distinctive feature is their formation in conditions of high humidity, which is created due to the temporary accumulation of moisture from surface runoff or the insignificant depth of soil and groundwater - in the region of 3-7 meters.
This type of soil develops under the cover of meadow-steppe plants. This area is characterized by a variety of grass species. Also, soil can form under sparse grassy forests, in low relief areas, and in the area of floodplain terraces. This type of soil is often found on plains with poor drainage.
The water regime of this type of land is characterized by reciprocal capillary recharge, which is replaced by deep wetting of the soil profile. This situation occurs during most of the growing season.
Morphological structure of the profile
The profile of this type of soil is characterized by the following type of morphological structure:
- Humus horizon A is distinguished by its dark gray color and loose structure. It may be granular or lumpy granular.
- Horizon AB – has a dark gray color with brownish impurities. It has a lumpy or coarse-grained structure. The parameters of the total thickness of humus horizons reach 35-70 centimeters. Boiling is observed in the lower part.
- The Bca horizon is located lower and is an unclearly defined illuvial-carbonate horizon. Carbonates are presented in the form of impregnation and in the form of cranes. This structure is typical for the lower part of the profile. In some cases, at a depth of 2-3 meters, small Fe-Mn nodules are found and symptoms of deep gleying are observed. They are unstable in time and space due to changes in groundwater levels depending on the season and year.
- Sk is a fawn-colored parent rock with traces of gleying. It is presented in the form of rusty ocher spots and veins.
Meadow-chernozem soils are characterized by an increased volume of humus compared to surrounding chernozems. They are considered very fertile. The only exceptions are solonchak and solonetzic genera. In terms of fertility parameters, such soils exceed chernozems.
Basic soil-forming processes
Key processes include the following:
- coagulation and biogenic structuring;
- humus-accumulative;
- eluvial-illuvial distribution of carbonates;
- unpronounced gleying.
How to use
This type of soil is considered more fertile than black soil. This is due to a better supply of moisture. The advantages of such soil are especially evident in dry weather.
In order to rationally use meadow-chernozem soils, it is worth carrying out the same measures as in the case of using chernozems. However, it is recommended to irrigate these types of soil very carefully. This is due to the risk of a rapid rise in groundwater levels, which could lead to subsequent salinization and waterlogging.
Since non-saline meadow-chernozem soils are considered the most fertile, they are actively being developed for arable land. Within the European part of Russia, such soils in their original state can only be found in protected areas.
This type of soil can be used for cultivating different types of agricultural vegetation in the corresponding zone. With active use, nitrogen and phosphorus fertilizing is required. They are recommended to be combined with organic substances.
Meadow-chernozem soils are characterized by a high degree of fertility.Therefore, they are actively used in agriculture. To prevent soil depletion, it is important to apply fertilizers in a timely manner.
