1. Soil and Natural Vegetation

2. SOIL
SOIL: surface layer of the earth, composed of mineral and organic materials, air , and water

3. SOIL True soil consists of 4 main parts:
1. Minerals,
2. Bacteria and Organic Material
3. Air
4. Moisture
If one of these parts is missing, the material cannot be considered soil

4. COMPONENTS OF SOIL

5. Minerals
The minerals in soil come from rock, known as the parent material.
Rock is broken down by weathering into smaller particles of sand, silt, and clay.
Many minerals are nutrients needed by plants for growth. e.g. calcium, potassium, etc.

6. Bacteria & Organic Materials
When plants & animals die, they are decomposed by bacteria in the soil.
As bacteria break down the organic matter, nutrients are released.

7. Bacteria & Organic Materials
Decaying organic materials form humus which provides nutrients and moisture for plants
HUMUS: Dark, upper layer of soil made up of partially decayed plant material
The process of decay is nature’s way of recycling nutrients
Humus gives the soil its dark colour

8. Air Air is found in all soils usually in between soil particles
Plants need air around their roots
Air spaces also created by insects / worms and small animals that tunnel through the soil

9. Moisture (Water)
Water dissolves nutrients in the soil and is then taken up by plants through their roots
Helps weather rock and decay organic materials

10. ANIMALS
Not an essential component of true soil but few soils exist w/o them (worms, mice, insects, etc.)
Helps distribute soil particles and nutrients & provide pathways / openings for water and air
Add organic material to the soil after they have died.

11. Soil Profile
O/A - TOPSOIL -this top layer contains humus. It is rich in organic material. It is dark brown/black in colour
B-SUBSOIL- combines minerals and organic layers
C- PARENT MATERIAL - mineral materials from which soil is made. Usually bedrock or glacial deposits

12. Soil Formation LEACHING CALCIFICATION Two processes contribute to soil

13. Leaching Is a continual downward movement of water through the soil
As the water moves down, it dissolves the chemical nutrients and carries them away
This downward movement removes nutrients that plants need
You can identify leached soil by its poor, often thin, topsoil layer
Leached soils can be developed into excellent farmland by adding fertilizers

14. Calcification Occurs in dryer climates
As water in the topsoil evaporates, water from below is drawn up to replace it - CAPILLARY ACTION
As the water reaches the surface, it evaporates leaving behind the minerals that were dissolved in it
The result is a thick topsoil layer, rich in minerals
Calcium is the main mineral deposited
near the surface
In very dry climates the amount of mineral deposits can be poisonous to plants

15. Vegetation Regions

16. Natural Vegetation Natural Vegetation - refers to
those plants that grow without
any human interference

17. Natural Vegetation There are seven natural vegetation regions
across Canada:
TUNDRA
BOREAL AND TAIGA FOREST
MIXED FOREST
DECIDUOUS FOREST
GRASSLANDS
CORDILLERA VEGETATION
WEST COAST FOREST

18. TUNDRA It is located above the tree line
Climate is cold and dry so trees
do not grow
It has permafrost
Only the active layer (top metre or so of permafrost, thaws during the short summer
Small shrubs, mosses, and lichen grow close to the ground
Little humus is found in the Tundra’s
thin layer of soil

19. BOREAL and TAIGA FOREST
South of the Tundra is the Boreal and Taiga forest
It is the largest vegetation region in Canada
Coniferous (evergreens) trees grow here
The needles are acidic, so they make the soil acidic
The lack of humus, the high acidity and the leaching make these soils infertile and unsuitable for agriculture
White and black spruce, balsam fir, and pine grow sparsely along the northern edge of the boreal forest
They are harvested by pulp and paper and lumbering companies

20. BOREAL and TAIGA FOREST
Coniferous trees can withstand the harsh,
northern conditions because:
They extract nutrients from the poor soil with their long roots
Sticky sap acts like anti-freeze
Waxy needles and thick bark prevent
the loss of moisture
The needles and flexible branches
shed snow
The needles conduct photosynthesis
on warm days

21. Mixed Forest South of the Boreal forest in eastern Canada
Mixed forest of coniferous and deciduous trees
Spruce, fir, pine, cedar and hemlock, maple, beech, ash, oak and birch
Excellent resource for the lumbering industry
It is a transition zone between the Boreal forest to the north and the deciduous forest to the south
Humus is created because of all
the leaves
Soils in mixed forest regions
are suitable for farming

22. Deciduous Forest
Only deciduous forest in Canada is found in southwestern Ontario
Only small remnants remain because it has been cleared for farming and urban developments
These trees need at least five months of warm weather
Soils are similar to those of the
mixed forest but contain more
humus
The most fertile soils of eastern
Canada

23. Grasslands The grasslands, or prairies, are
located in the southern part of
Manitoba, Saskatchewan,
and Alberta
Climate is too dry for most species
of trees to survive
Aspen, willow, and spruce grow in river valleys
Grass is suited to this dry climate - grass dies off on the surface, but its roots remain alive

24. Grasslands
Short grasses, sagebrush and cactus are the only types of vegetation which can survive here
The land can be used for grazing animals, particularly cattle
The long grass prairie is ideal for growing grains and oil seeds
Rich black soil is created from humus - grasses die

25. Cordillera Vegetation
Vegetation varies
Temperatures are warmer in the valleys than in the mountains
Grasses and cactuses grow in the dry, hot valleys and soils are similar to the prairie grasslands
Vegetation changes with altitude
Forests of coniferous trees grow on lower slopes
The vegetation on the higher slopes of the mountain ranges is similar to that of the tundra

26. West Coast Forest
Along the West Coast of Canada grow lush forests of Douglas Fir, spruce, red cedar, and western hemlock
Heavy rainfall and mild climate provide excellent growing conditions
Trees have played a crucial role in B.C’s forest industry
The lush vegetation provides
a lot of plant material to
make humus