week 3 - soil orders

Question 1

the 12 soil orders

Answer 1

1. Alfisols: mildy acidic clays
2. Andisols: volcanic ejecta
3. Aridisols: dry
4. Entisols: recent
5. Gelisols: permafrost
6. Histosols: organic
7. Inceptisols: beginning B
8. Mollisols: soft, dark
9. Oxisols: oxides
10. Spodosols: spodic horizon
11. Ultisols: strongly acidic clays
12. Vertisols: swelling clays

Question 2

mildy acidic clays (soil order)

Answer 2

alfisols

Question 3

volcanic ejecta (soil order)

Answer 3

andisols

Question 4

dry (soil order)

Answer 4

aridisols

Question 5

recent (soil order)

Answer 5

entisols

Question 6

permafrost (soil order)

Answer 6

gelisols

Question 7

organic (soil order)

Answer 7

histosols

Question 8

beginning B (soil order)

Answer 8

inceptisols

Question 9

soft, dark (soil order)

Answer 9

mollisols

Question 10

oxides (soil order)

Answer 10

oxisols

Question 11

spodic horizon (soil order)

Answer 11

spodisols

Question 12

strongly acidic clays (soil order)

Answer 12

ultisols

Question 13

swelling clays (soil order)

Answer 13

vertisols

Question 14

alfisols

Answer 14

• has a Bt horizon
• moderate base saturate (35-50%)
• lower fertility than moll’s, but still excellent
• common under deciduous forests, grasslands
• profiles:
  
  • A E Bt1 Bt2 C
  • A Bt1 Bt2 BC

Question 15

andisols

Answer 15

• dev’d from volcanic material
• A are rich in Al-humic materials
• secondary minerals predominately amorphous
• range in dev from moderate to well-dev’d
• uncommon worldwide, but common in PacNW

Question 16

aridisols

Answer 16

• dry soils; arid to semi-arid environments
• typically less plant fgrowth, A has less OM
• can have many B types, but Bk’s are common

Question 17

entisols

Answer 17

• young, weakly developed soil
• typically NO B HORIZON (unless coarse, poorly formed Bw)
• C, AC, OC, OAC
• common ridgetops, recent deposits (rivers, beaches), urban areas
• quite a bit in WA from glacial deposits

Question 18

gelisols

Answer 18

• soils w/ permafrost or cryoturbation (mixing from frost heaving)
• cold or frozen much of the year
• can be organic or inorganic soils

Question 19

histosols

Answer 19

• organic soil (little mineral material)
• O hzns
• found in waterlogged areas of any type of climate: WETLANDS
• can be fertile when drained, but difficult to manage due to poor physical properties
• Oa, Oe, Oi

Question 20

inceptisols

Answer 20

• relatively young, have B horizons (usually Bw)
• more dev’d than entisol, but less than all others

Question 21

mollisols

Answer 21

• ‘mollic’ A hzn (>50% base saturation, good phys. properties)
• usually under grasslands
• VERY fertile
• profiles:
  
  • A B_ C
  • A C
  • A E B_ C

Question 22

oxisols

Answer 22

• most highly weathered, old soils
• laterization - oxic B hzn (Bo)
• oxides prevalent, kaolinite common
• low OM
• common in tropical areas w/ high rainfall, stable landscape

Question 23

spodisols

Answer 23

• has spodic hzn (Bs & Bhs)
• illuvial accumulation of Fe, Al, OM
• usually has E horizon
• acidic, lower fertility
• cooler, temperate regions, high leaching
• O, E, Bhs, Bs, C

Question 24

ultisols

Answer 24

• old, highly weathered
• low base saturation (< 35%)
• has a Bt hzn
• lower fertility than alfisols
• common under forests
• dev’d in wetter temperate areas or tropical areas
• O, A, Bt1, Bt2, Bt3, C

Question 25

vertisols

Answer 25

• high content of shrink/swell clay in upper 1m of soil
  
  • montmorillonite
• soil expands/contracts
• Deep A hzn
• cracks open in dry season, material falls in and cracks shut in wet seasons - mixes soil