What is humus?
The various soil organisms breakdown both organic and mineral materials in the soil partly by enzymatic action and partly by taking the materials in as nutrients and metabolizing them further. Most of the breakdown products are used by the plants as nutrients or are lost into the soil environment. A small portion of these breakdown products, however, perhaps 5% or so, becomes resistant to further decomposition and become more or less stabilized. Humus is that remaining, more or less homogenous mix of more or less stable material. “Detritus” is the proper term for the recognizable debris from dead plants and animals. Humus is the dark colored, sweet smelling, goo. Humus is often called, “Black Gold” because of its great value to plants, soil, and the soil microorganisms.