Zonal Classification of Soil by USDA-12 Soils Categorized YouTube Lecture Handouts

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Zonal Classification of Soil by USDA - 12 Soils Categorized

Zonal Classification of Soil

Zonal Classification of Soil
Table of Soil Order
Soil orderDefining characteristicsPercent earth land area
AlfisolModerate leaching; B horizon enriched in clay; humid forest vegetation9.77
AndisolVolcanic-ash parent material0.73
AridisolHot, dry climate; weak B horizon18.53
EntisolLittle or no horizonation or swelling clay10.61
GelisolPermafrost within 2 m of land surface-
HistosolOrganic parent material1.84
Global Distribution of Alfisols
Distribution of Andisols
Global Distribution of Aridisols
Global Distribution of Entisols
Global Distribution of Gelisols
Global Distribution of Histosols
Table of Soil Zonal Classification
InceptisolLittle or no B horizon development21.80
MollisolThick, soft, black A horizon5.99
OxisolHot, humid climate; A horizon enriched in iron & aluminum oxides & kaolinite7.00
SpodosolCool, humid climate; B horizon enriched in iron & aluminum oxides & organic matter; sandy parent material3.45
UltisolWarm, humid climate; B horizon enriched in clay; extensive leaching8.12
VertisolLittle or no horizonation; high content of swelling clay2.23
Global Distribution of Inceptisols
Global Distribution of Mollisols
Global Distribution of Oxisols
Global Distribution of Spodosols
Global Distribution of Ultisols
Global of Distribution of Vertisols

Soil Orders Associated with Climates

  • Oxisols - Af [Aw]
  • Ultisols - Cfa [Af, Aw]
  • Alfisols - Aw, Cs, Cfa, Dfa, Dfb
  • Spodosols - Dfb, Dfc
  • Gelisols - ET [Dfc, Dw]
  • Mollisols – dry sections of Cfa, Dfa, Dfb and wet margins of BSk
  • Aridisols - BWh, BWk