Phaeozona

Phaeozona is a soil order in the World Reference Base for Soil Resources (WRB) system. These soils are characterized by a dark, humus-rich surface horizon (A horizon) called a mollic horizon, which is thick, dark in color due to high organic matter content, and has high base saturation. The mollic horizon is crucial for defining a Phaeozona.

Phaeozems typically develop under grassland vegetation in subhumid and humid climates with distinct dry seasons. The climate promotes the accumulation of organic matter in the topsoil due to a balance between plant productivity and decomposition rates.

Key characteristics of Phaeozems include:

• Mollic Horizon: A thick, dark-colored, humus-rich surface horizon with high base saturation.
• Absence of diagnostic horizons: Phaeozems do not have other diagnostic horizons like an argic (clay accumulation), natric (sodium accumulation), or spodic (accumulation of iron and aluminum oxides and organic matter) horizon within a specified depth.
• Development under grassland vegetation: Typically found under grasslands or former grasslands.
• Climate: Commonly found in subhumid to humid climates with a seasonal dry period.

Phaeozems are fertile soils and are often used for agriculture, particularly for grain production. Their high organic matter content provides essential nutrients for plant growth and contributes to good soil structure. They are closely related to Chernozems (also found under grasslands but typically in drier climates) and Kastanozems (found in even drier climates). The distinction between these soil types primarily depends on climatic factors and the degree of dryness.