In subalpine and alpine zones with sparse tree cover or dwarf shrub vegetation on limestone or marlstone and between rubble of these rocks, the Moder subtype Pechmoder may develop. The name derives from the dark colour (German Pech = pitch). The humus form is characterised by a highly biologically active Oxh horizon that consists mainly of faecal pellets of the mesofauna (springtails, oribatid mites, enchytraeids, insect larvae). The Oxh with a fine granular structure has a high base saturation. Distinct features are:

  • Ol and Of horizons are present all year round; and
  • Oxh horizon is present that either directly overlies the bedrock, or fills the voids in the rubble or, more rarely, overlies mineral soil.

Black Oxh horizont with a fine granular structure, filling up the surface and the interspace of limestone, diagnostic horizon of  Pechmoder,   © Gerhard Milbert