Soil Horizon

A distinct layer within a soil profile. The main layers commonly encountered in turf maintenance are the O Horizon for the organic layer; A Horizon for the Topsoil or Rootzone layer; B Horizon, for the Subsoil layer; and C Horizon for the Parent Material (unconsolidated / loose rock). Other Horizons which might be encountered are: the R Horizon (Parent Material consolidated rock, i.e. bedrock). The O Horizon may also have distinct sub-layers, these being called L (Litter); F (Fermentation) and H (Humification) and may also be called layers, zones, or horizons. In addition, there may also be what is termed the E Horizon. Sometimes this term is just referred to as a Horizon.