Presentation on theme: "Soil Erosion. What do trees do to soil? Tree roots are in the soil. The roots help to keep soil in place. When the trees are in the soil, the soil does."— Presentation transcript:
What do trees do to soil? Tree roots are in the soil. The roots help to keep soil in place. When the trees are in the soil, the soil does not move easily
If trees are cut down, what happens to the soil? The soil becomes ‘loose’. It is more easily moved
How can soil be moved? Rain and wind can move soil
Wind can move soil on top of the ground
When rain hits the ground, it can loosen soil. Then, when rain flows on top of the ground, it can carry some soil with it
What kinds of things are in soil? Chemicals and elements in soil are called nutrients
Two common elements in soil are Nitrogen (N) and Phosphorus (P) Where do these elements go? Some of these elements are absorbed by tree roots
Nutrients are absorbed by tree roots
What happens to these elements when trees are cut down? The elements stay in the soil. Until….Rain and wind come..
If the nutrients go too deep, things will not be able to grow in the soil because the roots cannot reach the nutrients. The soil loses its fertility.
When rain comes into the ground, it carries or dissolves the nutrients in the soil If nutrients are brought further down in the ground, what happens to the quality of the soil?
The soil loses fertility
Where else can the nutrients go? Nutrients can also be carried by rain and by water underground. Nutrients can be carried across instead of down
Where do the nutrients go then? Nutrients can be carried all the way into rivers, lakes and streams
What happens to the lakes if the Nitrogen and Phosphorus get carried into them? Here is a hint…What things do we know like Nitrogen and Phosphorus Algae and plants can begin to grow in lakes
Algae can grow very quickly and start to take over water Algae can take up oxygen from lakes. Then what happens to fish?
If too much algae grows, fish can die and water can so nutrient rich that it becomes contaminated Water can become undrinkable, unusable to use to wash with or swim in