Tropical Soils

Key terminology:

the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms

• Sol biota

• Catena

• Humus

• Regolith

Key Terminology:
the breaking down of rocks, soil, and minerals in situ

• Weathering
• Erosion
• Calcification
• Sesquioxides

Key Terminology:

drain away of solubles from the soil by the action of percolating liquid, especially rainwater.

• Percolation

• Infiltration

• Through flow

• Leaching

Key terminology:

a reddish clayey material, hard when dry (concretion), forming a topsoil in some tropical regions

• Red and Brown earth

• Oxisol

• Laterite

• Laterization/hydrolysis

Key terminology:

Small compounds or nutrient cations, are moved out of the soil profile by leaching. The two exceptions to this process are iron and aluminum oxides. What are they called?

• Red and Brown earth

• Oxisol

• Laterite

• sesquioxides

Key terminology:

The B horizon of the soil for tropical red earth (savannah) is enriched with calcium carbonate from water moving downward through the soil, or upward by capillary action of water from below.

• Capillary action

• Calcification

• Carbonation

• Hydrolysis

Key Terminology:
the upward movement of water through the soil against the force of gravity.

• Leaching
• Inversion
• Drawback
• Capillary Action

Oxisol Soil

• Rainforest

• Savanna

Tropical Red and Brown Earths

• Rainforest
• Savanna

Depth of rainforest soil.

• 2-4m

• up to 15m

• up to 30m

• up to 42m