Soil Profiles and Soil Classification What processes result in the formation of soil horizons? What...
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Transcript of Soil Profiles and Soil Classification What processes result in the formation of soil horizons? What...
Soil Profiles and Soil Classification
What processes result in the formation of soil horizons?
What are the typical characteristics of O, E, A, B, C and K horizons?
What is CEC? % base saturation? How do these vary among differentsoil types?
What is the role of clay minerals in nutrient retention?
How are soils classified? What are the characteristics of each of the followingsoil orders:
oxisol, alfisol, spodosol, mollisol, aridisol
Soil Horizons:
O – Organic(>50%) plus minerals (<50%)
A – Eluvial; resistate minerals plus organics
B – Illuvial; clays, oxides, active weaterhing
K – Cemented (carbonates, silica, gypsum)
C – Partially weathered parent material
Soil pH:
Organic decay – carbonic and organic acids
Mineral buffering capacity – carbonates – fastsilicates – medium to slow
Leaching –removal of buffer systems – wet climate soilsmore likely to be acidic; arid soils to be alkaline
Acid – 6.0 or lessNeutral – 6.0 to 7.5Alkaline (basic) – 7.5 or greater