INTRODUCTION

Brown soils, often referred to as brown forest soils or brown earths, are well drained with brownish subsoils where iron oxides created through weathering processes are bonded to silicate clays.
Other properties such as texture and level of fertility depend on the nature of the parent material and the degree of alteration it has undergone. In Scotland, their occurrence is restricted to the warmer, drier climate characteristic of eastern areas but they also occur in sheltered highland glens at lower elevations and on areas of base-rich parent materials. Under natural conditions the soils would form under broadleaf forest which promotes rapid decomposition of plant residue and consequent recycling of plant nutrients.

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Profile Characteristics

Ah	Surface horizon, usually relatively thin with organic material (mull humus) incorporated throughout mineral matrix.
Bw	Brightly coloured mineral subsoil, with good structural development, generally merges into:
C	Relatively unaltered parent material, usually brightly coloured or colour inherited directly from parent rock.

Two factors have influenced the development of these soils:

• Sufficient depth of soil parent material, which is neither extremely siliceous nor extremely calcareous, and which is permeable to permit free aeration.
• A bioclimate regime, which promotes rapid decomposition of plant residues and recycling of plant nutrients. Where this happens the plant residues are broken down by fungi/ bacteria
  to be incorporated into the soil by earthworms to create MULL humus. If the breakdown is slower, moder humus is formed. Subsequently hydrous iron oxides inherited from the parent material or formed by weathering remain attached to any silicate clays.