Soils Flashcards
How long does it take for zonal soils to form?
Hundreds of years
What are zonal soils?
Consist of weathered rock, organic water and air. Form under a long period of time under the influence of vegetation and climate
What are zonal soils dependent on?
Climate, topography, parent material, living organisms and time
What order are soils arranged in zonal soils?
Surface (O)
Topsoil (A)
Subsoil (B)
Parent material (C)
Bedrock (R)
What is the O horizon?
The surface.
Organic debris, partly decomposed
What is the A horizon?
The topsoil.
Mineral particles mixed with organic material
What is the B horizon?
The subsoil.
Compounds draining from above accumulate
What is the C horizon?
Partly weathered rock
What is the R horizon?
Bedrock
Where are ferralsols found?
In tropical regions
What are ferralsols?
Deep and intensely weathered. Often red or yellow. Low pH (acidic). High levels of Fe and Al in B horizon. Rapid decomposition of organic material plus large amounts of rainfall can cause leaching. Most nutrients found in O&A horizons
What is farming like with ferralsols?
Drain well to reduce soil erosion.
Not good at holding water, creating drought conditions.
Crop rotation common. Permanent vegetation cover prevents erosion
What are ferralsols commonly used to cultivate?
Black pepper and rubber in Brazil.
Coconut and oil palm in Indonesia
How long do podzols take to develop?
3000-5000 years
What are podzols?
Mature soils. B horizon can become hard, causing poor drainage and waterlogging. Dark O&A horizons which store large amounts of nutrients. Acidic
Where are podzols found?
In areas of high precipitation levels and cool temperatures
What is farming like with podzols?
Low in nutrients & very acidic. Unsuitable for arable farming. Deep ploughing to promote water drainage and continual fertilisation sometimes allow for crop growth
What are podzols commonly used for?
Forestry, recreation and extensive grazing
What causes soil erosion?
Water and wind
What is wind erosion?
Caused by agricultural removal of hedges, deforestation, etc. Which removed wind barriers and often coincides with droughts
What is salinisation?
Salt building up in the soil happens because of irrigation and evaporation. Can be prevented by careful irrigation or growing salt tolerant crops
What is waterlogging?
Soil too wet and saturated to grow. Reduced yield and increased water erosion. Improve drainage to fix
