Soil Genesis and Development, Lesson 4 - Soil Profile Development Glossary


Condition that is lacking molecular oxygen. Under this condition, organisms that do not require molecular oxygen will survive and funtion well.


Breakdown into constituent elements through chemical change.

organic matter

The total of the organic compounds in soil, exclusive of undecayed plant and animal tissues, their "partial decomposition" products, and the soil biomass. The term is often used synonymously with humus. (Glossary of Soil Science Terms. Soil Sci. Soc. Am. 1998)

parent material

Rock or minerals which are weathered to form smaller particles of a soil. Parent material is one of the five factors contributing to formation of a specific soil. In the Great Plains, much parent material is associated with ancient seas or glacier deposits.

soil horizons

A layer of soil or soil material approximately parallel to the land surface and differing from adjacent genetically related layers in physical, chemical, and biological properties or characteristics such as color, structure, texture, consistency, kinds and number of organisms present, degree of acidity or alkalinity, etc. (SSSA)