Podzols

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:

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

UTILISATION

[1] Podzols are generally infertile and are physically limiting soils for productive use. They are extremely acid, have high C/N ratios, are lacking in most plant nutrients, except within the H and upper mineral horizons. Where they are used for arable cropping long-term fertilisation is required. They are also used for rough grazing and for forestry or recreation.