Soil is a vast reservoir for a wide diversity of organisms. Plant roots explore this diversity daily. Various other animals consume smaller creatures either intentionally or unintentionally by foraging on plant roots, insects, and microorganisms.

Soil ecology is the study of how soil organisms interact with other organisms and their environment – their influence on and response to numerous soil processes and properties form the basis for delivering essential ecosystem services. Some of the key processes we study in soil are nutrient cycling, soil aggregate formation, and biodiversity interactions.

Organic matter is a keystone component of soil, upon which many other processes and properties are intricately linked. Soil organic matter is an assorted mixture of organic compounds, having been processed over varying lengths of time by soil microorganisms. It may be living (e.g. plant roots, insects, fungi, protozoa, or bacteria) or it may be dead, dying, or partially decayed. The most abundant constituent of soil organic matter is carbon (50-58%), hence the congruence between soil organic carbon and soil organic matter.