"Humus" (Origin: 1790–1800; < Latin: earth, ground)'s degraded organic material in soil, which causes some soil layers to be dark brown or black. In soil science, humus refers to any organic matter that's reached a point of stability, where it'll break down no further and might, if conditions don't change, remain essentially as it's for centuries, if not millennia. In agriculture, humus's sometimes also used to describe mature compost, or natural compost extracted from a forest or other s… (More on Humus)