soilformation

Soilformation, also known as pedogenesis, is the process by which soil develops from parent material through physical and chemical weathering, biological activity, and amendments over time. It results in a soil profile with distinct horizons and a dynamic interface between geology, biology, and climate. The classic five-factor model identifies climate, organisms, relief, parent material, and time as primary drivers of soil formation.

The main processes are addition (deposition of organic matter and minerals), transformation (weathering and chemical change), translocation (movement of material within the profile by water, wind, or organisms), and loss (erosion, leaching). Weathering creates minerals; organic matter accumulates from plant and microbial activity, forming the O horizon and contributing to humus. Horizons form: O, A, E, B, C, R.

The rate and outcome depend on climate (temperature and moisture), organisms (plants, microorganisms, burrowing animals), relief (slope, aspect that controls drainage), parent material (composition and mineralogy), and time. Over long periods, horizons develop and differentiate; in young soils, horizons may be poorly defined; in old soils, extensive weathering can lead to highly leached horizons and specific soil orders.

Soil scientists classify soils using systems such as Soil Taxonomy or WRB. Understanding soilformation aids land management, agriculture, forestry, and environmental studies by predicting fertility, drainage, and resilience to erosion.