Pedology in the context of Soil classification

Soil formation, also known as pedogenesis, is the process of soil genesis 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 science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils.

The main branches of soil science are pedology ― the study of formation, chemistry, morphology, and classification of soil ― and edaphology ― the study of how soils interact with living things, especially plants. Sometimes terms which refer to those branches are used as if synonymous with soil science. The diversity of names associated with this discipline is related to the various associations concerned. Indeed, engineers, agronomists, chemists, geologists, physical geographers, ecologists, biologists, microbiologists, silviculturists, sanitarians, archaeologists, and specialists in regional planning, all contribute to further knowledge of soils and the advancement of the soil sciences.

Edaphology (from Greek ἔδαφος, edaphos 'ground' + -λογία, -logia) is concerned with the influence of soils on living beings, particularly plants. It is one of two main divisions of soil science, the other being pedology. Edaphology includes the study of how soil influences humankind's use of land for plant growth as well as people's overall use of the land. General subfields within edaphology are agricultural soil science (known by the term agrology in some regions) and environmental soil science. Pedology deals with pedogenesis, soil morphology, and soil classification.

Soil morphology is the branch of soil science dedicated to the technical description of soil, particularly physical properties including texture, color, structure, and consistence. Morphological evaluations of soil are typically performed in the field on a soil profile containing multiple horizons.

Along with soil formation and soil classification, soil morphology is considered part of pedology, one of the central disciplines of soil science.

A relict, in geology, is a structure or mineral from a parent rock that did not undergo metamorphic change when the surrounding rock did, or a rock that survived a destructive geologic process.

Some geologic processes are destructive or transformative of structures or minerals, and when a process is not complete or does not completely destroy certain features, the left-over feature is a relict of what was there before. For example, relict permafrost is an area of ancient permafrost which remains despite a change in climate which would prohibit new permafrost from forming or it could be a fragment of ancient soil or sediment found in a younger stratum. A relict sediment is an area of ancient sediment which remains unburied despite changes in the surrounding environment. In pedology, the study of soil formation and classification, ancient soil found in the geologic record is called a paleosol, material formed in the distant past on what was then the surface. A relict paleosol is still found on the surface, and yet is known to have been formed under conditions radically different from the present climate and topography.

Perturbation (from Latin: perturbare "to confuse, disorder, disturb", from per- "through" + turbare "disturb, confuse," from turba "turmoil, crowd") is a set of pedology (soil study) and sedimentary geology processes relating to changes in the nature of water-borne alluvial sediments and in situ soil deposits over time.

Pedoturbation (from Greek: πέδον (pédon), "soil") involves mixing between soil horizons and is an important factor in soil formation. Pedoturbation includes churning clays, cryoturbation, and bioturbation. Pedoturbation transforms soils through destratification, mixing, and sorting, as well as creating preferential flow paths for soil gas and infiltrating water.