Soil formation or soil genesis refers to changes of soil properties with time in one direction: the content of one component or mineral in a certain horizon decreases or increases, sedimentary layering disappears, etc. Mostly, such changes are slow, and can be seen only after decades to millenia. So most soil properties that change during soil formation are relatively stable. Sometimes, however, effects of soil formation can be seen within weeks or months. Examples are the quick drop in pH when sulfides oxidize to sulfuric acid upon exposure to air, and the formation of gley mottles when a soil becomes very wet. Most rapid processes are cyclic, however, and not are considered part of soil formation.
KeywordsSoil Organic Matter Soil Property Soil Profile Parent Material Soil Formation
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