1. Soil and Vegetation

2. Soil has 4 main parts Minerals:
Come from the weathering (chemical and physical) of the parent material. This is rock broken down into sand, silt and clay, releasing nutrients needed by plants.

3. 2. Bacteria and Organic Materials:
Bacteria break down organic materials (leaves, dead animals, bugs, etc.) returning nutrients to the soil. This is called humus, and gives soil its dark colour (this part is also known as topsoil).
Topsoil formation is a slow process. Over the last years only cm of topsoil have formed in Canadian forests, and cm of topsoil in the grasslands of the prairies

4. 3. Air:
Plants need air around their roots. Air pockets in soil can be created by humus, burrowing worms, insects and small animals
4. Moisture:
Water dissolves nutrients in the soil and is then taken up by plant roots. It is also necessary in the chemical and physical processes that weather rock and decay organic materials.

5. The Soil Profile (horizons)
“O” Horizon: Humus
Thin layer of soil rich in plant matter that is not fully decomposed
“A” Horizon: Topsoil
Rich in organic materials, especially near surface. Dark brown or black in colour
“B” Horizon: Subsoil
Combined mineral and organic layer. Lighter brown in colour
“C” Horizon: Parent Material
Mineral materials from which soil is made. Usually bedrock or glacial deposits.

6. Soil and Natural Vegetation
How could soil affect vegetation?
The main factors affecting the type of flora in any landscape and its distribution:
1.Soils Prevailing climate 3.Relief
All species have a set of ideal conditions for their needs. Plants are suited to (and adapt to) their surrounding prevailing conditions.
There is a huge range in the combination of soil/climate/topographic conditions around the world…this can be seen in the wondrous range of flora around the world!

7. YOUR TASK: OLD TEXTBOOK
Textbook pg. 155
Read chapter 13 and answer questions 1-8 & #11 on Page 155 & 156

8. YOUR TASK:
Textbook pg. 160 “Issue: do we treat our soil like dirt?”
Read with a partner and answer 1. a) and b). (we will discuss as a class later)
2. Use the information on page 162 to help you and your partner fill in the “Leaching and Calcification” diagram in your own words.