Living, Teaming Soil

Soil is mixture of solids (minerals and organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following:

• horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter; or
• the ability to support rooted plants or soil (micro)organisms in a natural environment.

Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil is a three-state system of solids, liquids, and gases.

Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion.

(From Wikipedia)

One is usually able to distinguish different layers within soils, called soil horizons. These horizons interact with each other, and therefore cannot be considered as independent, although they can be very different from each other. There is great complexity and diversity in soil horizons, but in general the surface horizons are dynamic and rich in life and organic matter. Below the surface horizons, one often finds more stable horizons that are formed through a diverse suite of soil formation processes, such as bright white horizons formed through the removal of clays or deep-red, low-fertility horizons formed through millions of years of weathering. Below these horizons, soils transition into layers that are only partially affected by soil formation and ultimately into unaltered layers of parent material.

Some scientific definitions restrict the term dirt to displaced soil.