The soil is home to a large proportion of the world’s biodiversity. The top eight inches of soil of one acre area may contain as much as five and half tons of bacteria and fungi. Soil organisms breakdown organic matter, making nutrients available for uptake by plants and other organisms. A gram of garden soil contains around one million fungi, such as yeasts and moulds. Bacteria and fungi play key roles in maintaining a healthy soil. They act as decomposers that break down organic materials to produce detritus and other breakdown products. Soil detritivores, like earthworms, ingest detritus and decompose it.
