soil

As a flooring material, sports pitch, or ground surface, soil is a naturalistic layer composed of particulate mineral matter mixed thoroughly with organic material. It is generally compacted and flattened, without plant growth. It can be laid down as an optional material or left in its original state as a matter of convenience.

The exposed layer is the mineral-and-organic soil mixture itself. A surface covered by dense grass belongs to a different ground-material meaning.

The soil can be placed deliberately or retained where it naturally occurs. Compaction and flattening do not make it a manufactured paving material.