Assertion: soil | /r/HasAspect | organic horizon
Facets:
value: on the surface
type: LOCATION
Source sentences:
text: Besides the three major soil horizons of (A) surface/topsoil, (B) subsoil, and (C) substratum, some soils have an organic horizon (O) on the very surface.
text: Some soils have an organic horizon (O) on the surface, but this horizon can also be buried.
text: Some soils have an organic horizon (O) on the surface, but this horizon can also be buried.