Soil Orders

Question 1

Entisols

Answer 1

• found in floodplains of rivers, steep rocky land, sand dunes, urbanized land, mined or dredged soils (areas with constant deposition)
• no B horizon

Question 2

Inceptisols

Answer 2

• more mature profile development than entisols
• found in cold regions, mountains and steep slopes
• Cambic horizon (Bw)

Question 3

Gelisols

Answer 3

• found in tundra
• permafrost layer and cryoturbation
• B horizon missing
• high in frozen organic matter

Question 4

Histosols

Answer 4

• cold wet regions
• large accumulations of organic matter
• usually formed in a waterlogged area
• Some layers are peaty while others are mucky

Question 5

Andisols

Answer 5

• formed in layers of volcanic ash
• Mineral soils with low bulk density
• low activity allophane clay, glassy sand
• High P stores
• excellent physical properties for agriculture

Question 6

Vertisols

Answer 6

• found in warm sub-humid to arid environments, grasslands
• must have >30% expansive clay
• layers slide over each other and blend together
• wide deep cracks
• usually black due to development from slum-rich materials
• high in Ca and Mg

Question 7

Aridisols

Answer 7

• dry landscapes with sparse vegetation
• B horizon and a small A horizon
• high pH
• moist for fewer than 90 consecutive days

Question 8

Mollisols

Answer 8

• typically found in Grassland areas (Great Plains, Steppes, Pampas)
• large Mollic epipedon
• must have >50% base saturation
• may or may not have a B horizon
• Usually no E horizon

Question 9

Alfisols

Answer 9

• areas with trees and forest vegetation
  (cool to humid areas as well as semiarid tropics and Mediterranean climates)
• distinct accumulation of Bt horizon (Argillic horizon)
• Have high % of Ca and Mg

Question 10

Spodosols

Answer 10

• found in warmer, wetter forested areas
• sandy, acidic
• ash-like E horizon
• Organic matter and iron precipitated in dark B horizon
• presence of a spodic horizon

Question 11

Ultisols

Answer 11

• similar to Alfisols with significantly more weathering
• accumulation of clays in the Bt horizon (NO ARGILLIC HORIZON)
• redder soils because of iron oxidation
• very high acidity

Question 12

Oxisols

Answer 12

• typically rainforests (Wettest and warmest)
• oldest, most weathered soil formation
• accumulation of oxides and some clays
• relatively uniform with depth