soil mineral and organic horizons Flashcards
how do we further subdivide the A, B, C horizons
by adding suffixes to further distinguish the major mineral horizons. there is also an organic horizon (LFH, O)
what is Ap horizon
a horizon disturbed by human (PEOPLE) activities (or the PLOW layer)
what is the Ah horizon
a horizon enriched with organic matter (HUMUS) and characterized by dark colour and granular structure
what is the Ae horizon
a horizon characterized by the ELEVATION of clay, organic matter, iron, or aluminum alone or in combination it is typically lighter in color than the Ah horizon and may have a distinctive “platy” structure
what is a Bt horizon
it is enriched with clay (TEXTURE contrast) it is an illuvial horizon and forms below an eluvial horizon
what is a Bm horizon
MINIMALLY altered by pedogenic processes to give a change in colour of structure or both
what is Bn horizon
horizon which Na as accumulated. usually has prismatic or columnar structure and occasionally has a round top columnar structure. very hard when dry
what is the Cca horizon
horizon enriched with carbonates (CaCO3) compared to parent material
what is Ck horizon
horizon containing original Ca and Mg
what is Cg horizon
horizon with evidence of mottling and Gleying due to water saturation. usually has a grey color associated with reduction of iron oxides
what are major organic horizons
horizons containing 17% or more organic C
what is the L, F, H horizon
consist of organic materials the occur from the accumulation of leaves, twigs, and woody debris that ovaries mineral soil
where are L, F, H horizons most commonly found
forests
where do O horizons develop
primarily from bog vegetation (peat)
developed in water-saturated conditions
what does L stand for
Litter-relatively fresh residue
