1. SOIL AND NATURAL VEGETATION Physical Geography

2. Soil  Soil is made up of 4 main parts: Minerals Organic and Bacterial materials Moisture Air  Think -MOMA

3. Minerals  Comes from parent material (usually rock) or loose material deposited from a glacier  Minerals become part of the soil when rock is broken down by weathering

4. Organic and Bacterial Material  Dead plants and animals are decomposed by bacteria in soil, nutrients are released to form humus  Humus provides nutrients and moisture to plants and gives soil its dark colour.

5. Moisture  Water dissolves nutrients in soil allowing plants to take them up through their roots  Water is also needed in the processes that weather rock and decay organic material

6. Air  Air in soil is created by high humus levels (loose, decaying material allows for many air pockets), worms, insects and small animals  Plants need air around roots

7. Typical Soil Profile

8.  Horizon O  Leaf litter, organic material (grass)  Horizon A  Top Soil  Rich in organic materials  Dark brown or black in colour  Horizon B  Sub Soil  Combined mineral and organic layer  Lighter brown in colour  Horizon C  Parent Material  Mineral materials  Usually bedrock or glacier deposits

9. What happens if the soil is too wet?  Leaching- the excess water dissolves nutrients and carries them away (downward), making it difficult for plant roots to reach nutrients  Leached soil has poor, usually thin topsoil layer Much of Canada is covered with Wet-Climate soil

10. What if the soil is too dry?  Calcification-there is an upward movement of water  As water in the top soil evaporates, water from below is drawn up to replace it  As water evaporates, it leaves behind minerals  Topsoil is thick and rich in minerals  If soil is very dry, the amount of minerals left can create a layer that is poisonous to plants

11. Natural Vegetation Regions  Draw a cross section of a typical soil sample in your notes (copy from page 147- fig 13-2)  Color a map showing the Soil Regions of Canada(figure 13-1, page 146)