2023年7月27日发(作者：)

FAO/UNESCO System of Soil Classification

First and Second Level Classes of the FAO System with Simple Definitions

Acrisols:

Acidic soils with a layer of clay accumulation. Under the modified legend this class consists only of clays with low cation exchange capacity.

Ferric Acrisols

Gleyic Acrisols

Haplic Acrisols, added to the revised legend.

Humic Acrisols

Orthic Acrisols, deleted in the revised legend.

Plinthic Acrisols

Alisols:

A new soil class of formerly Acrisols with clays with high cation exchange capacity.

Ferric Alisols

Gleyic Alisols

Haplic Alisols

Humic Alisols

Plinthic Alisols

Stagnic Alisols

Andosols: Dark soils formed from volcanic materials with little horizon development.

Gelic Andosols, added to the revised legend.

Gleyic Andosols, added to the revised legend.

Haplic Andosols, added to the revised legend.

Humic Andosols, deleted in the revised legend.

Mollic Andosols

Ochric Andosols, deleted in the revised legend.

Umbric Andosols, added to the revised legend.

Vitric Andosols

Anthrosols: New class of soils formed by human activities.

Aric Anthrosols

Cumulic Anthrosols

Fimic Anthrosols

Urbic Anthrosols

Arenosols: Sandy soils with little profile development.

Albic Arenosols

Calcaric Arenosols, added to the revised legend.

Cambic Arenosols Ferralic Arenosols

Gleyic Arenosols, added to the revised legend.

Haplic Arenosols, added to the revised legend.

Luvic Arenosols

Calcisols: New class of soils with accumulation of calcium carbonate.

Haplic Calcisols

Luvic Calcisols

Petric Calcisols

Cambisols: Soil with slight profile development that is not dark in color.

Calcaric Cambisols, added to the revised legend.

Calcic Cambisols, deleted in the revised legend.

Chromic Cambisols

Dystric Cambisols

Eutric Cambisols

Ferralic Cambisols

Gelic Cambisols

Gleyic Cambisols

Humic Cambisols

Vertic Cambisols

Chernozems: Dark soils rich in organic matter.

Calcic Chernozems

Gleyic Chernozems, added to the revised legend.

Glossic Chernozems

Haplic Chernozems

Luvic Chernozems

Ferralsols: Highly weathered soils rich in sesquioxide clays and with low cation exchange

capacities.

Acric Ferralsols

Geric Ferralsols, added to the revised legend.

Haplic Ferralsols, added to the revised legend.

Humic Ferralsols

Orthic Ferralsols, deleted in the revised legend.

Plinthic Ferralsols

Rhodic Ferralosols

Xanthic Ferralosols

Fluvisols: Alluvial and floodplain soils with little profile development.

Calcaric Fluvisols

Dystric Fluvisols Eutric Fluvisols

Mollic Fluvisols, added to the revised legend.

Salic Fluvisols, added to the revised legend.

Thionic Fluvisols

Umbric Fluvisols, added to the revised legend.

Gleysols: Water saturated soils that are not salty.

Andic Gleysols, added to the revised legend.

Calcaric Gleysols

Dystric Gleysols

Eutric Gleysols

Gelic Gleysols

Humic Gleysols, deleted in the revised legend.

Mollic Gleysols

Plinthic Gleysols, deleted in the revised legend.

Thionic Gleysols, added to the revised legend.

Umbric Gleysols, added to the revised legend.

Greyzems: Dark soils rich in organic matter.

Gleyic Greyzems

Haplic Greyzems, added to the revised legend.

Orthic Greyzems, deleted in the revised legend.

Gypsisols: New class of soils with an accumulation of calcium sulfate (gypsum).

Calcic Gypsisols

Haplic Gypsisols

Luvic Gypsisols

Petric Gypsisols

Histosols: Soils very rich in organic matter (>14%).

Dystric Histosols, deleted in the revised legend.

Eutric Histosols, deleted in the revised legend.

Fibric Histosols, added to the revised legend.

Folic Histosols, added to the revised legend.

Gelic Histosols

Terric Histosols, added to the revised legend.

Thionic Histosols, added to the revised legend.

Kastanozems: Dark soils rich in organic matter.

Calcic Kastanozems

Gypsic Kastanozems, added to the revised legend.

Haplic Kastanozems

Luvic Kastanozems Leptosols: New class of soils that are shallow in depth and with weak profile development.

Dystric Leptosols

Eutric Leptosols

Gelic Leptosols

Lithic Leptosols

Mollic Leptosols

Rendzic Leptosols

Umbric Leptosols

Lithosols: Thin soils over rock. Removed from the revised legend.

(no suborders)

Lixisols: New soil class, formerly Luvisols, with clays with low cation exchange capacity.

Albic Lixisols

Ferric Lixisols

Gleyic Lixisols

Haplic Lixisols

Plinthic Lixisols

Stagnic Lixisols

Luvisols: Soils with strong accumulation of clay in the B-horizon and not dark in color.

Under the revised legend these soils have clays with high cation exchange capacity.

Albic Luvisols

Calcic Luvisols

Chromic Luvisols

Ferric Luvisols

Gleyic Luvisols

Haplic Luvisols, added to the revised legend.

Orthic Luvisols, deleted in the revised legend.

Plinthic Luvisols, deleted in the revised legend.

Vertic Luvisols

Nitisols: New class of soils with shiny surfaces on structural faces (peds) of the soil.

Haplic Nitisols

Humic Nitisols

Rhodic Nitisols

Nitosols: Acid soils with a very thick layer of clay accumulation. Removed from the revised legend.

Dystric Nitosols

Eutric Nitosols Humic Nitosols

Phaeozems: Dark soils rich in organic matter.

Calcaric Phaeozems

Gleyic Phaeozems

Haplic Phaeozems

Luvic Phaeozems

Stagnic Phaeozems, added to the revised legend.

Planosols: Soils with a light colored layer over a soil layer that restricts water drainage.

Dystric Planosols

Eutric Planosols

Gelic Planosols

Humic Planosols, deleted in the revised legend.

Mollic Planosols

Solodic Planosols, deleted in the revised legend.

Umbric Planosols, added to the revised legend.

Plinthosols: New class of mottled, clayey soils that irreversibly harden after repeated drying.

Albic Plinthosols

Dystric Plinthosols

Eutric Plinthosols

Humic Plinthosols

Podzols: Soils with a strongly bleached layer and a layer of iron or aluminum cemented organic matter.

Cambic Podzols, added to the revised legend.

Carbic Podzols, added to the revised legend.

Ferric Podzols

Gleyic Podzols

Haplic Podzols, added to the revised legend.

Humic Podzols, deleted in the revised legend.

Leptic Podzols, deleted in the revised legend.

Orthic Podzols, deleted in the revised legend.

Placic Podzols, deleted in the revised legend.

Podzoluvisols: Soils similar to both Podzols and Luvisols.

Dystric Podzoluvisols

Eutric Podzoluvisols

Gellic Podzoluvisols, added to the revised legend.

Gleyic Podzoluvisols

Stagnic Podzoluvisols, added to the revised legend. Rankers: Shallow, dark soils rich in organic matter and formed from siliceous material. Removed from the revised legend.

(no suborders)

Regosols: Surface layer of rocky material. Coarse texture Regosols have been incorporated in the Arenosols under the revised system.

Calcaric Regosols

Dystric Regosols

Eutric Regosols

Gelic Regosols

Gypsic Regosols, added to the revised legend.

Umbric Regosols, added to the revised legend.

Rendzinas: Dark soils rich in organic matter over calcareous material. Removed from the revised legend.

(no suborders)

Solonchaks: Salty soil with little horizon development.

Calcic Solonchaks, added to the revised legend.

Gleyic Solonchaks

Gypsic Solonchaks, added to the revised legend.

Haplic Solonchaks, added to the revised legend.

Mollic Solonchaks

Orthic Solonchaks, deleted in the revised legend.

Stagnic Solonchaks, added to the revised legend.

Takyric Solonchaks, deleted in the revised legend.

Solonetz: Salty soil with a high concentration of sodium.

Calcic Solonetz, added to the revised legend.

Gleyic Solonetz

Gypsic Solonetz, added to the revised legend.

Haplic Solonetz, added to the revised legend.

Mollic Solonetz

Orthic Solonetz, deleted in the revised legend.

Stagnic Solonetz, added to the revised legend.

Vertisols: Clayey soils that form deep (>50 cm), wide (>1 cm) cracks when dry.

Calcic Vertisols, added to the revised legend.

Chromic Vertisols, deleted in the revised legend.

Dystric Vertisols, added to the revised legend.

Eutric Vertisols, added to the revised legend.

Gypsic Vertisols, added to the revised legend. Pellic Vertisols, deleted in the revised legend.

Xerosols: aridic soils. Removed from the revised system.

Calcic Xerosols

Gypsic Xerosols

Haplic Xerosols

Luvic Xerosols

Yermosols: aridic soils. Removed from the revised system. Yermic has been added to the

management phases.

Calcic Yermosols

Gypsic Yermosols

Haplic Yermosols

Luvic Yermosols

Takyric Yermosols