Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. combination inorganic/organic material
7. soil
8. [soil by composition or origin]

Anotations

Scope note:

Dark brown or black non-living organic substance derived from microbial decomposition of plant and animal substances on the surface of the earth. Living plants derive nutrients from the forms created by this decomposition.