How Soil Is Formed - Soil: Reflections on the Basis of our Existence - page 30

horizon and at ￅkerb￤ck it reached a depth of twenty centimetres. Below it was a
reddish layer known as the illuviated horizon. The reddish colour comes from iron
and aluminium dissolved from the upper soil layers, a process aided by the seep-
age of dissolved acids from organic material lying at the surface.
Podzol is commonly found in Swedish coniferous forests and forms on acidic
bedrock where the decomposition process is slow and in areas of plentiful rainfall
that accelerates the leaching of minerals to the lower layer of soil.