Soil classification according to the FAO–UNESCO Soil Map of the World - Fundamentals of the Physical Environment - page 869

Soil units of the FAO classification (1988
revision)

Symbol Soil Group Main features

AC Acrisols Argillic B of low clay activity

AN Andosols Soils on volcanic ash

AL Alisols Argillic B with high activity clays and aluminium

AT Anthrosols Soils affected by human cultivation and/or disturbance

AR Arenosols Coarse-textured soils without horizons

CM Cambisols Brown earth with a weathered B horizon

CL Calcisols Soils with a calcic or petrocalcic horizon

CH Chernozem Soils with a black humic A horizon

FR Ferralsols Soils have a B horizon of sesquioxides

FL Fluvisols Raw soils on recent alluvium

GL Gleysols Wet soils with gleyed horizons

GR Greyzems Soils with humic A and argillic B horizons

GY Gypsisols Soils with a gypsic or petrogypsic horizon

HS Histosols Soils dominated by organic material (peaty)

KS Kastanozems Soils with humic A and calcic or gypsic B horizons

LP Leptosols Shallow soils over hard rock

LX Lixisols Soils with argillic B horizon of low clay activity

LV Luvisols Soils with argillic B of medium/high clay activity

NT Nitisols Other soils with a deep argillic B horizon

PH Phaeozems Humic A over varied horizons

PL Planosols Heavy texture in the B horizon

PT Plinthosols Soils with plinthite causing surface wetness

PZ Podzols Soils with podzolic B horizon

PD Podzoluvisols Argillic B with irregular top

RG Regosols Soils of unconsolidated materials

SC Solonchaks Salt-enriched soils

SN Solonetz Soils with alkali B horizon

VR Vertisols Black deeply cracking clays