Soil erosion Flashcards
What is soil
A thin layer on the surface of the earth and is home to many forms of life.
What would happen without soil
Plants would not grow and animals and humans would not be able to get food from the soil.
At what rate does the natural forms of soil erosion occur
They Takes place at the same rate that soil is formed
What human activities cause soil erosion
Overgrazing and deforestation.
What is the top layer of the soil called
Topsoil
What happens when the topsoil is eroded
The soil will no longer be suitable for agricultural purposes or other vegetation.
What are the negative side effects of soil erosion by water
As water flows over the land, it carries soil and agricultural pollutants into the rivers. This can lead to the silting of dams, poisoning of drinking water, harming of fish and plant life and disruption of the ecosystems found along the course of the river
What are the main causes of man made soil erosion
Agriculture, construction and mining
Why is man made soil erosion a problem
Because humans are stripping soil from the surface of the earth faster than nature can replace it.
What are agricultural practices cause soil erosion (name 7)
Overstocking and overgrazing, removing trees, using pesticides and chemical fertilizers, ploughing up and down the slopes, lack of crop rotation and surface irrigation
How does overstocking and overgrazing cause soil erosion
Plants protect the soil. If there are too many animals on the land the will destroy the plant cover allowing soil to be washed or blown away.
How does removing trees cause soil erosion
Trees removed from agricultural land allows wind to have long, open, distances to travel, increasing the rate of soil erosion.
How does using pesticides and chemical fertilizers cause soil erosion
Pesticides and fertilizers can kill small organisms that bind the soil. The small loose particles can be carried away by water or wind.
How does ploughing up and down cause soil erosion.
This leads to rain washing away the soil
How does lack of crop rotation cause soil erosion
Planting the same crop every year depletes the soil of nutrients and the soil becomes infertile.
How does surface irrigation cause soil erosion.
As the water hits the ground with enough force it causes the soil to erode.
How should farmers prevent soil erosion
- avoid overgrazing
- allow indigenous plants to grow that will bind the soil
- limit the use of pesticides and fertilisers
- use contour ploughing and leave unploughed grass strips between ploughed land.
- use a crop rotation system
- use a drip irrigation system
How does construction cause soil erosion
- When land is cleared of vegetation for building sites or roads, the soil is exposed and is easily eroded by wind and water.
- and when roads, factories or homes are built, large areas of land are covered by tar and concrete. These surfaces cannot absorb the rain, and this increases run-off
What is run-off
Rainfall that doesn’t sink into the soil but runs over the land
What is infiltration
Rainwater that sinks into the ground
What carries run-off water and sediment away from sites
Paved roads, pavement gutters and storm sewers
What is much of the sediment in urban areas contaminated of
Fuel, oil and other chemicals