biosphere Flashcards
Explain the main conditions and processes involved in the formation of Podzol (8 marks)
- coniferous vegetation, pine needles
broken down slowly due to cold climate
results in mor humus which is highly acidic
precipitation > evaporation, leads to leaching of water and minerals down thru profile
known as eluviation
this makes the A horizon ash grey
iron pan forms at bottom which impedes drainage and can cause waterlogging
build up of materials here is known as podzolisation
leaching causes the B horizon to be reddish-brown
soil is thin - rate of formation is slower dye to little organic matter and biota
horizons are well defined - shallow tree routes and no biota
Explain the main conditions and processes involved in the formation of Gley soil (8 marks)
forms in areas of heavy rainfall or very cold temperatures
Due to the climate - little vegetation,
due to this mor acidic humus will eventually form
The A horizon - very dark because organic material is broken down slowly due to the climate and lack of biota
often waterlogged parent material not being weathered
This leads to anaerobic environment which causes gleying
Gleying is when the soil turns a blue/grey colour because the iron on the soil doesn’t get any oxygen
Explain the main conditions and processes involved in the formation of brown earth soil (8 marks)
abundance of leaf litter from deciduous vegetation
broken down quickly - temperate climate these soils form in, as well as the activity of soil biota like earth worms
thick layer of mull humus, which is mildly acidic
It is dark in colour high nutrient and organic content
Horizons aren’t well defined due to the activity of the soil biota which mix the soil
This is aided by the deep routes of trees, which also spread nutrients through the soil
The parent material is well weathered which means the soil is free draining and unlikely to get waterlogged
This soil profile is deep of the large supply of leaf litter for decomposition
