Soils Flashcards
How are soil horizons labelled?
O, A, B, C, R
What is the O horizon in soils?
organic matter
What is the A horizon in soils?
Topsoil
What is the B horizon in soils?
Subsoil
What is the C horizon in soils?
Unconsolidated material
What is the R horizon in soils?
Bedrock/parent material
Where are Vertisols found?
SE Asia, in tropical monsoon climate
Where are Gelisols found?
polar tundra climate
What percentage of the World’s population is supported by gelisols?
0.1%
What % of the Earth’s surface is gelisols?
13%
What % of particles in vertisols are clay-sized?
30%
What feature of clay soils makes them suitable for rice farming?
impermeable when saturated
How do vertisols mix?
shrinking and swelling due to varying dry and wet climate
How do gelisols mix?
cryoturbation
frozen soil freezes and melts, when it melts, nutrients and soil can move across horizons
What % of the Earth’s surface is vertisols?
2.7%
How does soil impact agriculture?
- determines type of crops that can be grown and whether crops can be grown at all
- determines the time-taken and the need for human intervention (TFP)
- impact vulnerability to change
What do gelisols store?
carbon
What are the 2 main types of soil erosion?
water and wind
What are the 4 types of water soil erosion?
- sheet
- gully
- rill
- river bank
What are the 4 types of wind soil erosion?
- saltation
- abrasion and attrition
- suspension
- creep
When does wind erosion occur?
when force exerted by wind is greater than gravity and the cohesive forces acting on the soils
How much damage does wind cause in the Great Plains of the USA per year?
30million ha
How much soil has been eroded annually? How has this impacted agriculture?
75 million tonnes = 9 million ha in productivity
What are the impacts of soil erosion on agriculture?
- need more inputs
- crops damaged due to sediments in the wind
- loss of nutrients and fertilisers
What are the environmental impacts of soil erosion?
- eutrophication
- change in the turbidity of water
- damage marine life and ecosystems
