Examine the characteristics of latosols
Explain the formation of Latosols
Write short notes on Laterisation and Podzolisation

• Presence of a thin humus layer due to intense bacterial activity
• Upper layer /A-Horizon contains much aluminium and Iron oxides
• Reddish in colour due to the concentration of iron aluminium oxides after intense leaching
• Great depth due to rapid weathering of the underlying rock and the C-Horizon
• Highly pervious
• Deficient in plant nutrients due to excessive leaching
• Soft when first exposed but soon become hard
• Horizons in the soil profile are not distinct
• Form in savannah and equatorial areas within relatively heavy rainfall that facilitates leaching
• Form above the water table where there is constant wetting and drying of the soil layer.

Formation of Latosols

Formed by the process of leaching. The soluble bases, sesquioxides and silica are removed from the upper layers /A-horizon and deposited in the lower AHorizon. This occurs mainly in the savanna and equatorial areas that receive heavy rainfall. / Rainwater mixes with carbondoxide to form a weak carbonic acid that dissolves soluble bases and removes them in solution. The insoluble minerals left behind therefore enrich the upper layer. Valuable mineral nutrients are leached to the lower layers and the soils remain poor.

Note: Since latosols are poor soils, they support short grasses and bush. Rearing of animals is a main activity in such areas.

Latosols also form good sources of materials for brick making and for murrum used in road construction.

Write short notes on Laterisation and Podzolisation

Laterisation

A process by which bases and silica are removed form the upper layer of the soil / A-horizon and deposited in the underlying B-horizon. The soluble minerals are removed in solution especially in areas receiving heavy rainfall. The process is particularly acute in tropical /savanna areas. The residues are called laterites / Lateritic soils. It has a concentration of hydrated oxides of iron and it is normally reddish in colour.

Podzolisation

It is a leaching process but on in moist, cool temperate areas (both latitudinally and altitudinally. Leaching removes bases, colloids and iron and aluminium oxides. The A-horizon becomes concentrated with non soluble silica while the B-horizon is rich in iron and clay. It is also dark because of these nutrients.

In the temperate lands the rate of decay is low and the soil is rich in humus and parlt decomposed vegetative materials. Is is infertile due to leaching .It supports mainly plants that thrive in acidic soils such as conifers.

2. To what extent is Climate responsible for soil formation in the Lake Victoria basin?