Formation of a Podzol

thin, black, acidic mor humus (pH 3.5-4) produced from slow decomposition of coniferous needles and cones due to cold climate.

limited bacterial activity due to cold climate which means the formation is slow and the soil is thin.

precipitation is greater than evaporation so there is downward leaching of clays, humus, iron and aluminium which gives an ash grey A horizon.

Podzols are found at all elevations from sea level to summit of the Cairngorms

the horizons are well defined as few soil organisms can survive in the cold climate

the C horizon is the parent material and is generally made up of weathered glacial material with a mixture of particle sizes and shapes.

over time, an iron pan can develop in the B horizon due to the deposition of iron which can then prevent drainage so the soil can become waterlogged.