Humus
/HYOO-mus/🪨 Soil Types●● Intermediate
Also known as: humic matter
Humus is the final product of organic matter decomposition — a dark brown to black, amorphous, colloidal material that is highly resistant to further decay. It has enormous water-holding capacity (up to 20 times its weight), provides cation exchange sites for nutrient retention, improves soil structure, and supports beneficial microbial communities. Humus content is a key indicator of soil fertility and health.
Etymology
From Latin humus (earth, ground, soil)
Example
“Years of composting had built up a humus-rich topsoil that was dark, crumbly, and teeming with earthworms.”