40 00 NORTH OCEAN NORTH ATLANT Troolc of Cancer Tropic of Caoricarn U PACIRC OCEA Antarctic Circle Soil Types Alfisols:gray to brown surtace soils, Inceptisols:weaky developed immature soils, Uissols:acidic and clayey soils of upland tropical medium to high base nutrients and organic content typically tundra or volcanic soils savannas:medium base nutrients Andisols:dry or desert soils:high in Mollisols:thick.dark soils of tallgrass praines; Vertisois:clay soils of moist tropical savannas: base nutrients and low in organic content high in organic content and base nutrients tend to crack and swell when dry Entisols:soils with poorty deveioped layers Oxisols:tropical and subtropical highly Mountain sois:thin sois,tending toward acidic: typically wind-deposited soils weathered soils:low in organic and base nutrients miced vareties based on vertical zonation Histosols:swamps and bog soits:wet,highly L相a or no soil orgsnic (peat and muck)content high in organic content and low in base nutrients6 UESTC-RSIP