Soil formation

Pedogenesis (from the Greek pedo-, or pedon, meaning 'soil, earth,' and genesis, meaning 'origin, birth') (also termed soil development, soil evolution, soil formation, and soil genesis) is the process of soil formation as regulated by the effects of place, environment, and history. Biogeochemical processes act to both create and destroy order (anisotropy) within soils. These alterations lead to the development of layers, termed soil horizons, distinguished by differences in color, structure, texture, and chemistry. These features occur in patterns of soil type distribution, forming in response to differences in soil forming factors.

Pedogenesis is studied as a branch of pedology, the study of soil in its natural environment. Other branches of pedology are the study of soil morphology, and soil classification. The study of pedogenesis is important to understanding soil distribution patterns in current (soil geography) and past (paleopedology) geologic periods.

Soil develops through a series of changes. The starting point is weathering of freshly accumulated parent material. Primitive microbes feed on simple compounds (nutrients) released by weathering, and produce acids which contribute to weathering. They also leave behind organic residues. New soils increase in depth by a combination of weathering, and further deposition. Gradually soil is able to support higher forms of plants and animals, starting with pioneer species, and proceeding to more complex plant and animal communities.

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