Changing concepts in soil classification. The structure of

SET #9
soils of humid temperate regions with evidence of
redistribution of clay and/or or-ga-nic matter.
acid PODZOLS with a bleached eluviation horizon over
an accumula-tion horizon of organic matter with aluminium
and/or iron,
PLANOSOLS with a bleached topsoil over dense, slowly
permeable subsoil,
base-poor ALBELUVISOLS with a bleached eluviation
horizon tonguing into a clay-enriched subsurface horizon,
base-rich LUVISOLS with a distinct clay accumulation
horizon, and
UMBRISOLS with a thick, dark, acid surface horizon that
is rich in organic matter.