If we compare yellow soils and red soils, it turns out that these soils have a lot in common (characteristics of absorption capacity, soil formation process). These lands are typical for the subtropics and are characterized by a poor content of humus. However, they can be used to grow crops if fertilization and irrigation are done regularly.
Soil formation conditions
Zheltozems and krasnozems are low-fertility soils common in the subtropics. They are formed in humid and warm subtropical climates. Their composition is affected by systematic washing and leaching.Such soils are characterized by medium structure, high moisture capacity and low humus content.
Due to intensive washing, almost all primary minerals decompose and secondary rocks form. Soluble substances move down, while insoluble substances remain and affect the color of the soil.
The type of soil is formed in a climate in which the average annual temperature is 13-15 degrees. Winters in the subtropics are mild and summers are moderately hot. On the territory of such lands, 1000-3000 mm of precipitation falls annually, mainly in the autumn-winter period. The growing season of plants lasts, depending on the geographical location, from 200 to 365 days.
Characteristics of red soils and yellow soils
Despite the same climatic conditions for soil formation, these two types of soils have many differences. The main features depend on the relief, parent rock, and vegetation.
Composition and properties
Comparative characteristics (table):
| Criteria | Zheltozems | Krasnozems |
| Mechanical composition | Clayey, loamy, heavy loamy | |
| Structure | Lumpy-prismatic, weak structure | Lumpy-grainy |
| Moisture capacity | High | Average |
| Water permeability | Low | Average |
| Humus content | 3,5-5 % | 4-8 % |
| Humus horizon | 5-10 cm | From 5 to 20 cm |
| Reaction | Slightly acidic pH 5-6 | Acidic or slightly acidic pH 4-5 |
| Color | Yellow due to free highly hydrated iron compounds | Red or orange due to predominance of iron oxides |
| State | When there is excess moisture it is sticky, during dry periods it is dense. | |
| Mineral composition | High silica content, low iron and other minerals | High iron and aluminum content, low calcium, magnesium, potassium, sodium |
Structure and genesis
Schematically, the structure of yellow soils and red soils looks like this: under a thin layer (up to 5 cm) of slightly decomposed vegetation lies a humus layer (10-20 cm) of a brownish or grayish hue with a lumpy structure. Below it, starting from the transitional (15-20 cm), there is a metamorphic (clayey) dense horizon of yellow or red color (40-100 cm). Even lower is the mother rock.
As for genesis, the formation of both types occurs in an acidic environment under deciduous or herbaceous vegetation. Thanks to litter, a significant amount of biomass accumulates - up to 21 tons per 1 hectare. The genesis involves ash elements and nitrogen, which form the basis of plant root nutrition. The type of soil formation is podzol-forming and soddy. True, in red soils the process of podzolization itself is weakly manifested, in contrast to yellow soils.
Classification and use
Depending on the climate, vegetation, relief and specific location, yellow soils and red soils are divided into subtypes. These lands are classified according to the degree of saturation, structure, thickness of the humus horizon and other characteristics.
Main types of yellow soils:
- typical;
- podzolic-yellow earth;
- yellow earth-gley;
- podzolic-yellow earth-gley.
Main types of red soils:
- typical;
- podzolized.
Farmers have adapted both types of soil for growing heat-loving crops. Thanks to the warm and humid climate, citrus fruits, tobacco, cotton, grapes, wheat, tea bushes, essential oils and various fruit plants grow well on these lands. True, to obtain a good harvest, regular application of organic matter and mineral fertilizers (nitrogen, potassium, phosphorus) is recommended. During dry periods, artificial irrigation has to be carried out. But the warm climate allows you to grow two crops a year.
In addition to the poor mineral composition, there is another problem. The acidity of such soil is not suitable for growing the desired crops. Only tea bushes can be planted on acidic soils. Liming is required to grow citrus fruits, grains and fruit crops. When developing territories, anti-erosion measures are carried out in parallel.
