Mangaliso NtuliPedology and biogeography

GGR2A01

Soil forming factors and physical and chemical soil forming processes

Soil forming factors

• Organism • Topography• Time • Climate • Parent material

Soil processes

• There are five soil processes • Laterization • Podsolization • Gleization • Salinization • Calcification

Explanation of the five soil processes

• Laterization• Tropical and subtropical • Weathering • Eluviation and leaching

Podzolization

• Humid cold mid latitude climate and coniferous vegetation

• Decomposition • Strongly acidic • Acidic soil solution enhances eluviation and

leaching

Calcification

• Upwards movement of dissolved alkaline salt

• Calcium carbonate • Common in praire grassland

Salinization

• Similar to calcification• Upwards movement of dissolved alkaline salts • The difference is that salt deposits occur at or

near the soil surface • Also occurs in drier climates

Gleization

• associated with poor drainage • Accumulation of organic matter • Chemical reduction of irons

Classification of South African soils

Five surface horizons Distinct features such as high organic content Organic O Humic A Vertic A Melanic A Orthic A