GEOG 1266 Lecture Notes - Lecture 7: Usda Soil Taxonomy, Aridisol, Alfisol
13 Jun 2018
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GEOG NOTES 4/30/2018
DISTRIBUTION
A. ClORPT
a. S or s = fCl, O,R,P,T…
i. Factors of Soil Formation
1. Hans Jenny (1941)
ii. S= soil; s= any soil property
iii. Cl=climate
iv. O=organisms
v. R=Relief (topography)
vi. P=parent material (rock or sediment)
vii. T=time
viii. …=other
B. Soil Classification
a. USDA Soil Taxonomy
b. Hierarchical system
i. Order
ii. Suborder
iii. Great group
iv. subgroup
C. Soil Orders
a. Oxisols
i. Properties: Old, deeply weathered soils of the tropics with weak horizons,
strongly leached, depleted in base cations – calcium, K,Na,Mg, rich in iron
oxides – not good for agriculture
ii. Formation:
iii. Distribution: Tropical rainforests, amazon basin, congo basin
b. Alfisols
i. Properties: high amount of cations, humid-subhumid climates, contains
lots of clay, A-E-B-T Horizons, Moderately developed A horizons, well
expressed horizons
ii. Formation: Clay translocation – causes Bt horizon, s
iii. Distribution: Mid latitude deciduous forests,
c. Mollisols – Thick, dark A horizons, well expressed granular structure, reasonably
expressed horizons, calcium carbonate
i. Found in the great plains, eastern Europe, pampas argentina
d. Aridisols – poorly expressed horizons, little organic matter, thin, and have
accumulations of salts,
i. Not much leaching
ii. Found in deserts/southwest- Nevada, Arizona,
e. Spodosols
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