Chapter One: The Soils Around Us

What is soil? new definition

"The layer(s) of generally loose mineral and/or organic material that are affected by physical, chemical, and/or biological processes at or near the planetary surface and usually hold liquids, gases, and biota and support plants."

What is soil? Old definition

(i) The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants. • (ii) The unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects) and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.

Are soils a renewable resource?

Soil is non-renewable natural resource.

Why new soil definition is better?

The new definition is inclusive of diverse soil environments, including urban, hydric, desert, and even extraterrestrial soils

Problems with old definition

•Exclusivity to the planet Earth •Unconsolidated vs. consolidated soils •Multi-phase system• liquids, gases, and biota are also integral components •Soil processes• Emphasis on a simpler idea of physical, chemical, and biological processes• Can be applied to urban and disturbed soils