Understanding the fundamental properties of soils proceeds to better appreciation of soil fertility and fertilization, as well as soil management and conservation. Integrating nutrient management, soil management, and conservation leads to considering soil quality or health. Simply put, soil quality is the ability of a particular soil to function as desired. Some functions include crop production, water control, or structure support. There are many, many definitions.
Specific ones depend on the viewpoint of the user.
Some stakeholders consider soil to the living, breathing substance near the earth's surface which fosters life on all scales. Others consider it to be the aggravating skim on the earth's surface. The study of soil is not the study of dirt. Dirt does not have life sustaining properties. Greenhouse media is not soil either.