Soil erosion Flashcards
What is soil?
Soil is a valuable resource and it is a medium in which plants are grown
Plants are…. & man cannot….?
Plants are producers &
Man cannot produce their own food ( we are so lazy fr)
What does man depend on?
Man depends either directly or indirectly on plants as a source of energy. Therefore the study of soil and those characteristics which affect plant growth are important.
List the causes of soil erosion- (6)
1) Occurs when the topsoil/surface layer of soil is removed
2) Deforestation
3) Poor farming methods
4) Trampling of soil
5) Clearing of land for squatting
6) Overgrazing by animals
What does natural vegetation do? (Deforestation)
Natural vegetation covers and protects the topsoil from the elements: being blown away by the wind, or disturbed by heavy rainfall
What are soil particles bound together by? (Deforestation)
Soil particles are also bound together by root systems
List some ways vegetation can be removed and also what does it cause? (Deforestation)
When vegetation is removed, by the felling of trees, overcutting, overgrazing; topsoil is left bare and exposed
What happens when the sun’s rays fall directly on the soil? (Deforestation)
Sun’s rays fall directly on the soil an dries up the humus and evaporates soil water
What is dry soil more susceptible to? (Deforestation)
Dry soil is more susceptible to being blown away and eroded
What do heavy drops of rainfall disturb? (Deforestation)
Heavy drops of rainfall disturb the crumb structure
What happens to the soil which is disturbed and loosened by heavy rainfall? (3)
1) it is sometimes washed away into rivers and waterways.
2) Rivers tend to become choked with silt and overflow their banks.
3) This process occurs when soil from sloping areas is eroded.
Give a poor farming method (1)
Ploughing loosens the soil and destroys its natural structure
Give a poor farming method (2)
Failure to replace hummus after successive crop cycles and burning weed (wheyyyy farmers them rel Wildin) reduces the water holding capacity of the soil.
Give a poor farming method (3)
Burnt soil dries up easily and is susceptible to wind erosion
Too many animals in a small area of land… and (i.e)…?
(overgrazing 1)
will not make economic use of the grass/food they consume, as their growth rate will be too slow
(i.e) too many animals in a small area would not grow quickly because of the competion for food
What causes little plant cover? (overgrazing 2)
Sheep and cattle and goats graze very close to the ground, leaving little plant cover
What do grazing animals reduce? (overgrazing 3)
Grazing animals also reduce infiltration by compacting
the soil crumb structure due to the force applied by hooves. This is known as trampling impacts.
Look at the diagram for overgrazing
LOOOKKK ATTT THE DIAGRAMMM PLEASE PLEASE PLEASE PLEASE PLEASE PRETTY PLEASEEEE
Name a common contributing factor to soil erosion
Any factor which disrupts the crumb structure of topsoil or leaves it bare and exposed to the elements is a contributing factor to soil erosion.
What is sheet erosion? And what does it lead to?
Sheet erosion is the imperceptible removal of a thin layer of soil which usually leads to Rill erosion.
What is rill erosion and what does it lead to?
Rill erosion, in which water cuts channels. The channels deepen as the volume of water increases and this usually leads to Gulley erosion.
What is gulley erosion
Gulley erosion, where a large amount of topsoil is removed by running water. Gulleys are larger than rills and more pronounced.
list the order of erosions
sheet erosion—–> rill erosion —–> gulley erosion
What are RILLS?
Rills are very small channels or depressions in the soil
