It can be separated into O, A, B, and C layers, which are differentiated by their  composition.
The term regolith can refer to this, although it mostly applies to those found on the  moon. Colluvium and alluvium are forms of this. Another form, podsol, is found in boreal  forests. It can be separated into O, A, B, and C layers, which are differentiated by their  composition. Humus consists of decayed organic matter in this, while it is classified by  horizons. Formed from weathering and erosion of rock, components of it include clay, loam, and  silt. For 10 points, plants grow in what kind of ground?
The term regolith can refer to this, although it mostly applies to those found on the  moon.
soil [accept dirt; accept earth; prompt on “ground”]