QUESTION
Examine the distinctive characteristics of soils of the himid tropical regions
CAMEROON GCE JUNE 2012
ANSWER
The humid tropical regions are regions that are found in low lattitudes, located between latitude 23 and half ° north and south of the equator. The major soils types here include FERRALLITIC, FERRUGINOUS, TROPICAL BLACK EARTH, AND DESERT SOILS examine below.
- Ferrallitic soils are common in the tropical rainforest or equatorial regions formed as a result of high rainfall ( 2500mm) within the tropics. These soils results from much leaching, as such though chemical weathering is high due to favourable climatic conditions, bases are washed (leached) downward while insoluble iron and Aluminium sesqui oxides remain on the surface to give the poor reddish brown ferrallitic soils. These soils are found in Amazon basins, Congo basins and south Cameroon low plateau.
The main characteristics include;
- They contain abundant litter.
- Rate of breakdown of litter through decomposition is high.
- Laterization is a common pedogenic regime.
- Soils are extremely deep without any clear horizons, due to thorough mixing by soil organisms.
- Soils has a deep red yellowish colour owing to high concentration of iron and aluminium oxides.
Ferruginous soils. these soils fall between latitude 5° and 15° north and south of the equator and they belong to the tropical grassland regions. Such soils can be found in areas like Compose of Brazil, Savanna of West, Central and East Africa and the Savanna of Northern America.
These soils are characterized by;
- They are formed under tropical grassland regions.
- They have outstanding dry and wet periods.
- Capilary action is common during dry periods.
- Leaching is common during wet seasons.
- Soils are generally infertile and can not support any meaningful farming.
Tropical Black Earths. This soil type still fall within the tropical grassland regions but are mainly formed under dry conditions and are characterized by:
- Has deep black colour.
- Contain much calcium carbonate.
- Common in Tropical grasslands with seasonal drought.
- Fairly drained and resembles chernozems.
Dersert soils
They are located between latitude 15° and 35° north and south of the equator. The soils are found in almost all desert such as Kalahari desert, Thar desert, Namib and Sahara deserts.
The desert soils have the following characteristics.
- They develop under arid climates.
- Decomposition of litter is slow, due to low loisture contents.
- Low humus content, as such infertile.
- Soils are brownish-grey in colour.
- Leaching is completely absent due to absence of rainfall.
