PODZOLS


INTRODUCTION

The name Podzol is derived from the Russian words pod = under and zola = ash.

Podzols are widespread throughout Scotland, generally associated with acid parent material and semi-natural heath or coarse grassland vegetation and coniferous woodland. They are characteristic of any topographic position where aerobic conditions prevail and water can percolate freely through the upper part of the profile. They are found at all elevations from sea level to the summit of the Cairngorms.

CHARACTERISTICS OF PODZOL SOILS

  • Deep organic layer comprising L (litter), F (fermenting organic matter) and H (humus) 
    under forest, less under moorland
  • An ash-grey, structureless, silica rich E or eluvial horizon, generally grey in colour
  • Humus (Bh) and/or iron/aluminium (Bs) enriched illuvial horizons, 
    generally strong brown colours

    Their formation is based on a succession of processes, including:
    • The movement of soluble metal-humus complexes (iron and aluminium) out of the surface layer(s)
      to greater depth and formation of a grey, silica-rich horizon.
    • Subsequent accumulation of humus and iron/aluminium oxides in the subsoil.

In terms of topography, climate and vegetation, a number of podzol sub-groups have been
identified in Scotland:

  • Humus podzols
  • Iron humus podzols
  • Peaty podzols
  • Peaty gleyed podzols
  • Sub-alpine podzols
  • Alpine podzols

Iron Humus Podzol

Peaty Podzol

Alpine Podzol

 
Humus iron podzol under old Caledonian pine forest of
Abernethy, Inverness-shire
Peaty podzol with wavy thin iron pan, some evidence of gleying above pan, Dava Moor, near Grantown-on-Spey Alpine podzol developed
within snow-bed on
Cairngorm plateau