Soil Secrets 2: Understanding Humus

Michael Melendrez explains the source of humus and its role in healthy soil

See the Wikipedia article

In soil sciencehumus (coined 1790–1800; < Latin: earth, ground) refers to any organic matter that has reached a point of stability, where it will break down no further and might, if conditions do not change, remain as it is for centuries, if not millennia.

In agriculture, humus is sometimes also used to describe mature compost, or natural compost extracted from a forest or other spontaneous source for use to amend soil

It is also used to describe a topsoil horizon that contains organic matter (humus type, humus form, humus profile).