3. Soil degredation is….. The decline in quality of and quantity of soil
It includes:
Erosion by wind and water
Biological degredation (loss of humus and plant life)
Physical degredation (loss of structure, change in permeablility)
Chemical degredation (acidification, declining fertility, salinization, toxicity)
Erosion by water and wind accounts for 80% of the 20 million km of degraded land worldwide

4. The four types of Water erosion that occur are:
Sheet, Gully, Rill and Tunnel.

5. Rill erosion
Rill erosion is when small amounts of water concentrate into streams and erodes the soil to the depth of cultivation. Rill erosion can be filled through cultivating however soil loss can be high.

6. Sheet erosion
is when a thin layer of soil is removed from the surface of the soil profile caused when the water cannot infiltrate the soil quick enough or the soil is already saturated

7. Tunnel erosion Leaves large holes in land
Occurs due to water movement along channels and cracks in soils.

9. Gulley erosion Heavy falling rain drops loosen soil
large quantities of water infiltrate into unstable areas of soil profile.
This process cuts large channels into the soil profile which can be expensive to repair.

11. Acidification (chemical)
Acidity may trigger the release of toxic metals in soils
Kills plants

12. Salt affected soils (chemical)
Found in coastal locations and hot arid areas Capillary action brings salts to the upper part of the soil Salty soil is less fertile and salt can form a hard layer. Irrigation often increases this issue

13. Soil Degradation notes pg 58-59
List the 4 causes of soil or land degradation in order of importance in your view (from textbook p58). Explain your view. Using handout provided , filter the human causes under each heading.
What are the consequences of soil degradation?
Soil degradation is only a problem in poor countries? Do you agree with this statement? Explain your view.