Impact Of People On Soil Erosion Flashcards
Infiltrates
Sinks in slowly
Compacting
Pressing together firmly.
Overgrazing
Keeping more animals on the land than there is grass to feed them.
Soil structure
Soil structure refers to how particles of soil are grouped together.
How does running water and wind erode soil?
By picking it up and carrying it away as they move over the land.
What can also increase erosion?
Human activities increase wind and water speed and the volume of water which increases erosion.
How do humans contribute to erosion?
Through:
Agriculture
Construction
Mining activities
What does clearing vegetation for fields, buildings and roads mean?
To remove plants and their roots causing the soil to erode.
Why are plant roots necessary?
They hold the soil.
How does vegetation reduce erosion?
Vegetation slows the wind and running water down, reducing their erosive power. This allows the water to sink into the ground, or infiltrates it, leaving less water to flow over the surfaces as run-off which could erode the soil.
How does driving heavy vehicles over the land affect vegetation?
Tractors, build overs and ore-trucks press down on the soil, compacting it’s particles are packed tightly together to form a hard surface.
Hardened surfaces limits infiltration and make it harder for plants to grow into the ground. This decreases vegetation cover.
What does covering land surfaces with buildings, paved areas and tarred roads do?
Reduces infiltration and increased run-off and erosion.
How is soil disturbed by ploughing it digging it up for foundations and holes for mining?
Disturbed soil is loosened and eroded more easily, especially when left in large mounds. Soil animals are killed and the soil structure is damaged.
How does agriculture contribute to erosion?
In SA farmers produce many different kinds of crops and read animals such as cattle, goats and sheep. Bad farming practices have led to high rates of soil erosion in certain places.
How can rearing animals lead to soil erosion? (3)
By keeping more animals on the land then there is grass to feed them leads to overgrazing. This is the biggest contributor to soil erosion.
Grass is eaten more quickly than it can regrow causing less vegetation cover on land and soil erosion.
The animals also compact the soil as they walk along the same path over and over. This leads to the formation of deep gullies called dongas over time as the tracks are eroded and a large amount of soil is lost.
