the twelve usda soil orders entisols inceptisols mollisols alfisols spodosols histosols andisols...
TRANSCRIPT
![Page 1: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/1.jpg)
The Twelve USDA Soil Orders
Entisols
Inceptisols
Mollisols
Alfisols
Spodosols
Histosols
Andisols
Oxisols
Ultisols
Gelisols
Vertisols
Aridisols
![Page 2: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/2.jpg)
Gelisols
Soils with permafrost or cryoturbation (mixing from frost heaving)
Cold or frozen much of the yearCan be organic or inorganic soils
9% worldwide 7% US
![Page 3: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/3.jpg)
Entisols
Young, weakly developed soil Typically NO B horizon
(in some cases, can have a very coarse-textured, poorly formed Bw)
Typical profiles: C AC OC OACCommon on ridgetops, recent deposits (rivers,
beaches, ash…), urban areas
16% Worldwide12% US
A
C
![Page 4: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/4.jpg)
Inceptisols
Relatively young soils – have B horizonsMore developed than Entisols but less developed
than any other soil order (soil doesn’t meet the criteria of other orders)
10% Worldwide 9% US
![Page 5: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/5.jpg)
Andisols
Developed from volcanic materialA horizons that are rich in Al-humic materialsSecondary minerals are predominately amorphousRange in development from moderate
to well-developed
<1% Worldwide 2% US
![Page 6: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/6.jpg)
Aridisols
Dry soils; arid to semi-arid environmentsTypically less plant growth, A horizon with less OMCan have many types of B horizons, but Bk’s are common
12% Worldwide 9% US
![Page 7: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/7.jpg)
Mollisols
Have a ‘mollic’ A horizon (>50% Base Sat., with good physical properties)Usually under grasslandsVERY fertile soilsProfiles may be: A B_ C
A C or even A E B_ C
7% Worldwide22% US
![Page 8: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/8.jpg)
Alfisols
Has a Bt horizon Moderate Base Sat. (< 50% and > 35%)Lower fertility than Mollisols, but still excellent soilCommon under deciduous forests, grasslandsA, E, Bt1, Bt2, C A, Bt1, Bt2, BC
10% Worldwide15% US
![Page 9: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/9.jpg)
Ultisols
Old, highly weathered soil, acidicLow Base Sat. (< 35%)Has a Bt horizonLower fertility than AlfisolsCommon under forestsDevelop in wetter temperate areas or
tropical areas with lots of leachingO, A, Bt1, Bt2, Bt3, C
9% Worldwide10% US
![Page 10: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/10.jpg)
Oxisols
Most highly weathered, old soilsLaterization – has an oxic B horizonOxides prevalent, kaolinite commonA horizon low in organic matterCommon in tropical areas with high
rainfall, stable landscape
8% Worldwide<1% US
![Page 11: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/11.jpg)
Spodosols
Has a Spodic horizon (Bs, Bhs)Illuvial accumulation of Fe, Al, O.M.Usually has an E horizonAcidic, lower fertilityFound in cooler, temperate regions, areas of high
leaching, coarse textured soilO, E, Bhs, Bs, C
3% Worldwide3% US
![Page 12: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/12.jpg)
Vertisols
High content of shrink/swell clay in the upper 1m of soilMontmorilloniteSoil expands and contractsCracks open in dry season, material falls in and cracks shut in wet season—mixes soilSubhumid to semi-arid areasDeep A horizon
2% Worldwide2% US
![Page 13: The Twelve USDA Soil Orders Entisols Inceptisols Mollisols Alfisols Spodosols Histosols Andisols Oxisols Ultisols Gelisols Vertisols Aridisols](https://reader031.vdocuments.us/reader031/viewer/2022012916/56649f2f5503460f94c48a11/html5/thumbnails/13.jpg)
Histosols
Organic Soil (little mineral material)O horizonsFound in waterlogged areas of any type
of climate: WetlandsWhen drained, can be fertile but difficult to manage
due to poor physical propertiesOa, Oe, Oi
1% Worldwide1% US