Tropical Red SoilsLatosols

Zonal Soils of Equatorial Regions

• Occur in the continents of South America, Africa and South Asia.

• They are found near the equator.

• For example in Brazil.

• These countries all have an equatorial climate, that is very warm and very wet.

• Called Latosols.

Characteristics of Latosols

• Low humus• Heavy leaching• Red colour• Sometimes can have a

brick like surface.

• Short nutrient cycle• Can support very rich

vegetation.

Causes of Characteristics….

• Low humus content is due to the rapid breakdown of organic material due to the very hot and very wet climate.

• Leaching is intense, only iron and aluminium compounds remain,this gives soil its red colour.

• The nutrient cycle is short because there is fast plant growth and rapid decomposition. This means humus is formed and used before leaching occurs.

Main Process Involved

Laterisation

Laterites

• Loose topsoil is eroded.

• Iron and aluminium layers are exposed.

• The high temperatures bake this into a hard brick like surface.

• This surface cannot be cultivated.

• It is known as a laterite.

Latosol Soil Profile

Latosol Soil Profile

• O Horizon; A lot of organic matter, rapid decomposition.

• A Horizon; Very thin layer due to short nutrient cycle.

• B Horizon; Very deep, intense leaching.

• C Horizon; Parent rock.

Uses of Latosol Soils

• In many areas with latosol soils there are tropical rainforests.

• The soil type can be an obstacle to the development of profitable agriculture.

• If forest or vegetation is removed the soil can become infertile within a couple of years.

Exam Questions

• Compare and contrast the characteristics of any two soil types which you have studied. (80 marks)– Characteristics; Colour, Texture, Structure,

Humus, PH Value, Water content, Fertility.– Also contrast the processes causing these

characteristics, climate, locations and uses.