Soil Series Atlas

Soils of Iowa

541 soil series mapped on 29.75 million acres

050100150cm1 ft2 ft3 ft4 ftApTopsoil · plowed0–15 cm · 0–6 inA1Topsoil15–25 cm · 6–10 inA2Topsoil25–36 cm · 10–14 inBASubsoil grading from topsoil36–46 cm · 14–18 inBt1Subsoil · clay build-up46–81 cm · 18–32 inBt2Subsoil · clay build-up81–114 cm · 32–45 inBCSubsoil grading to parent material114–152 cm · 45–60 in050100150cmApTopsoil · plowed0–15 cm · 0–6 inA1Topsoil15–25 cm · 6–10 inA2Topsoil25–36 cm · 10–14 inBASubsoil grading fromtopsoil36–46 cm · 14–18 inBt1Subsoil · clay build-up46–81 cm · 18–32 inBt2Subsoil · clay build-up81–114 cm · 32–45 inBCSubsoil grading toparent material114–152 cm · 45–60 in
Tama, to scale.

Mollisols — soils with a thick, dark, organic-rich topsoil

The state soil, Tama, ranks 9th of 541 series here on 581,522 acres. First place goes to Fayette, an Alfisol covering 4.2% of the state’s mapped soil. Mollisols make up over half of the mapped soil (66.1%).

Atlas series mapped in IowaGuide: state soils and where series began

Soil orders in Iowa

AlabamaArizonaColoradoFloridaGeorgiaIndianaKansasMaineMassachusettsMinnesotaNew JerseyNorth CarolinaNorth DakotaOklahomaPennsylvaniaSouth DakotaTexasWyomingConnecticutMissouriWest VirginiaIllinoisNew MexicoArkansasCaliforniaDelawareDistrict of ColumbiaIowaKentuckyMarylandMichiganMississippiMontanaNew HampshireNew YorkOhioOregonTennesseeUtahVirginiaWashingtonWisconsinNebraskaSouth CarolinaIdahoNevadaVermontLouisianaRhode Island

Largest series in Iowa

  1. FayetteAlfisols · 1,261,689 acres4.24%
  2. ColoMollisols · 1,213,212 acres4.08%
  3. NicolletMollisols · 1,072,384 acres3.60%
  4. WebsterMollisols · 1,004,978 acres3.38%
  5. CanisteoMollisols · 969,906 acres3.26%
  6. ClarionMollisols · 848,564 acres2.85%
  7. GalvaMollisols · 701,149 acres2.36%
  8. DownsAlfisols · 594,080 acres2.00%
  9. TamaMollisols · 581,522 acres1.95%
  10. IdaEntisols · 558,318 acres1.88%

Atlas series mapped in Iowa

  1. Tama152 cm · Typic Argiudolls
  2. Lester203 cm · Mollic Hapludalfs
  3. Fayette185 cm · Typic Hapludalfs