Book 24, Question 132
What is humus, the dark crumbly part of soil?
Humus is the dark, crumbly material that forms when dead leaves, roots, and animal bodies break down for a long time. It soaks up water like a sponge, holds nutrients that plants need, and makes heavy soil looser and sandy soil better at holding water. Earthworms, fungi, and bacteria turn the scraps into humus. A handful of humus-rich soil smells earthy and sweet.
More fun facts
- Humus is the dark material that forms in soil when dead plants and animals break down.
- Fallen leaves, twigs and animal remains pile up and slowly decay.
- As they decay, they release nutrients that plants need.
- Earthworms help mix humus into the rest of the soil.
- Soil with humus is loose, so air and water can reach plant roots easily.
- Humus can form naturally, or people can help make it by composting.
Sources: National Geographic Education
Questions kids ask
Why do farmers care about humus?
Farming depends on the nitrogen and other nutrients found in humus.