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SOIL
A thin layer of loose material
Most important natural resource
because it grows food
SOIL COMPOSITION
What is soil composed of
Provides
Oxygen
and
nitrogen
Binds soil &
allows plants
to soak up
nutrients
Eroded
particles
of rock
Remains of dead
plants and
animals = Humus
Soil Profile
LEACHING
 This is where the rain washes away the minerals in the top soil.
 The minerals are washed downwards into the bottom layers.
 HOW DO FARMERS DEAL WITH THE PROBLEM OF LEACHING
SOIL TYPES
Ireland has two types of soil
BROWN SOILS
PODZOLS
• Found in places which had
• Found in places which had
Deciduous forests
Coniferous forest or bogland
• Found in places with less
• Found in places with more
rainfall
rainfall
• They are very fertile because:
• They are less fertile because:
* Less leaching
* More leaching
* Contain lots of humus
* Contain less of humus
* Dark brown colour
* Lighter in colour
• Best for tillage and dairy
• Used for rough grazing or
farming.
forestry.
• South, East and Midlands of
Ireland
EXTENSION
Draw map of world and mark in Tropical Soil areas
Diagram 7 p133
Tropical Climates: Central America
Tropical Soils
Tropical soil is… (Brown, Yellow, Red)
Tropical forests and plants decaying on the ground cause a lot of
__________________weathering.
This ________________weathering gives rise to DEEP / SHALLOW soils.
The ________________weathering also causes iron in the soil to change
to ________________
This is why the soil looks ___________________________.
WHY IS IT BAD TO CLEAR A TROPICAL FOREST?
SOIL AND VEGATATION
Plant litter
forms humus
which helps
form soil and
bind soil
Vegetation
Helps also
bind soil and
stops it
blowing away
Vegetation
grows and
drop leaves
and litter
Fertile soil
encourages
more plants
and
vegetation to
grow
Soil gathers
nutrients and
minerals from
humus and
parent rocks