THat would be humus. This answer apparently wasn't long enough so I'm just adding junk.
Regolith is the layer of weathered rock particles and decaying organic matter that lies above bedrock on Earth's surface. It consists of different layers, including topsoil and subsoil, and is crucial for supporting plant life and various ecosystems. Regolith is enriched by organic matter, making it essential for nutrient cycling and soil formation.
;