SOILS
Formed by weathering and erosion
weathering; Is the breaking of rocks into smaller rocks
by a physical or chemical process
erosion: When smaller rocks are carried away from parent rocks
because of wind or water
3 types of weathered rock (depending on the size)
clay (smallest)
sand (biggest)
silt (medium)
depending on the different quantities of each one, the soil will have different properties
has layers
HORIZONS
their formation takes thousands of years
O horizon
where dead plant matter is
A horizon
also called "biomantle"
where living organisms are
B horizon
subsurface
furthest roots go
C horizon
where bedrock is slowly degrading into soil
composed by large rocks and gravel
R horizon
just rock
Division of soils
ENTISOL
-no horizons
-very young
-most common type on Earth
INCEPTISOL
-sligtly more horizon development
GELISOL
-at high latitudes
permafrost
-little horizon development
SPODOSOL
-in coniferous and boreal forests
-acidic due to pine needles
-low fertility
ALFISOL
-rich in iron and aluminum
-usually under broadleaf and decidious forest
ULTISOL
-lots of iron
-subtropical locations
ARIDISOL
-dessert soils
(not sandy desserts)
MOLLISOL
-darkest and most fertile soil
.grassland soils
OXISOL
-low fertility
-rainforest soils
.very developed horizons
ANDISOL
-volcanic soils
-rich in nutrients
HISTOSOL
-wetland soils
-highly acidic
unstable and dangerous to build on
VERTISOL
-have a lot of clay on them
-dry out regularly
makes soil "break"
makes it impossible for horizons to be formed
factors that influence soil formation
CL.O.R.P.T
CL: climate
rainfall, temperature and humidity
O: organism
R: relief
change in elevation
P: parent material
T: time
with enough time, soil becomes more developed
formed by rocks decomposed by
sun
rain
wind
animals
plants