Soil-forming factors
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 10, Ch 1 "Resources and Development"; Class 11, Ch 5 "Geomorphic Processes"
Meaning
Five factors control how soil forms: parent material, topography (the shape and slope of the land), climate, biological activity and time. They always act together. Climate and biological activity are active factors because they drive the changes. Parent material, topography and time are passive factors because they set the conditions. Hans Jenny formalised this set of factors in 1941.
Example
Peninsular India has similar old rocks in many places but very different soils. Heavy rain and heat on the Western Ghats in Kerala produce leached laterite. Lower rainfall over the basalt of Maharashtra produces black soil.
Don't confuse with
- Soil formation (pedogenesis): this is the process. It goes step by step from weathering and the arrival of bacteria, mosses and lichens to a mature soil. Soil-forming factors are the conditions that control that process.
Related concepts
- Parent material
- Residual and transported soils
- Climate as a soil-forming factor
- Eluviation
- Illuviation
- Desilication
- Humus
- Peat