Humus is a dark, organic material that forms in soil when plant and animal matter decays
. It is rich in nutrients and retains moisture in the soil, making it an integral part of soil organic matter
. Humus contains the elements necessary for plant growth, such as nitrogen, phosphorus, sulfur, calcium, magnesium, and potassium
. It also improves soil texture, allowing oxygen and water to move through it
. Humus is different from decomposing soil organic matter, as it has no determinate shape, structure, or quality
. Humus is formed as a result of the complicated interplay between inorganic conversions and organic nematodes, and earthworms
