What is humus?
The soil in its composition contains many substances, among them - humus. Thanks to this upper organic soil layer, plants can get components from the earth through the roots from the ground.
About what soil is, you can read in our article What is soil.
What is humus: composition and origin
Humus is a substance that makes up about 90% of the organic compounds of the soil. It is also a complex of compounds of organic nature, a supply of nutrients that was formed in the soil during the life of soil organisms.
What is humus in terms of chemistry? This is a compound of humic and fulvic acids, as well as gumin. Acids, in turn, can be free or bound. The composition of this complex also includes waste products and undecomposed particles of living organisms (cellulose, amino acids, lignin, carbohydrates, etc.).
An important role in the formation of humus belongs to such organisms as earthworms.You can learn more about the formation of humus from our article How the soil is formed. At the same time, microorganisms (nitrogen-fixing bacteria) are mainly involved in the transformation of the remains of animal and plant organisms. They produce the humification of organic substances, making them further available for absorption by the root systems of higher plants.
Examples of the use of the word
The word "humus" can be used in such sentences: "The part of humus in black soil is 92%", "Humus is a heterogeneous system of high-molecular compounds" and so on.