Soils 1 Flashcards
What is soil?
a natural body covering the earth’s surface in which plants grow
Physical Composition: Soils are comprised of?
solids
liquids
gases
6 soil forming factors
Parent Material Organisms Climate Topography Time Man
Parent Material
original material from which the soil has developed
what does parent material consist of
unconsolidated partially weathered mineral or organic material
Igneous Rocks
form when molten rock cools
Sedimentary Rocks
form when sediment laid down by water is “cemented together” over time
Metamorphic Rocks
existing rock subjected to heat and pressure causing physical or chemical change
Sedentary - Residuum
develop when underlying rock weathers in place
Transported - Colluvium
detatch and move down slope via gravity
Transported - Alluvium
rivers or stream
Three types of Alluvium
floodplains
alluvial fans
deltas
Transported - Aeolian
soils formed in silt sized particles deposited by WIND
Transported - Marine
Soils that formed in residue of ancient sea beds, now dry land
Transported - Lacustrine
soils formed in residues of ancient lakes
Three types of weathering
biological
chemical
mechanical
Grass has a _____ pH level
neutral
Time - Very young
Parent material
Time - Adolescent
A Horizon
C Horizon
Time - Mature
A Horizon
B Horizon
C Horizon
Exposed bedrock
Time - Very Old
Clay
O Horizon depth
0”-2”
A Horizon depth
2”-10”
E Horizon depth
thin
B Horizon Depth
10”-30”
C Horizon Depth
30”-40”
O Horizon
“O” stands for organic matter, surface layer, large amounts of organic material
A Horizon
Top Layer of the soil, zone where the most biological activity occurs
E Horizon
pale, thin layer leached of its mineral and organic content, largely composed of silcates
B Horizon
“subsoil” mineral layers that may contain some clay or minerals such as iron or aluminum oxides
Plow Layer
the layer of soil that has been cultivated
Solum
Soil that has formed from parent material
Regolith
unconsolidated material above the bedrock
Hard pan
compacted layer just below the cultivation reach (choose different cultivation depths)
