One of the decomposers is the soil fauna. Land fauna is a living fauna on the ground, both living on the ground and in the soil. Some soil fauna, such as herbivores, actually feed on plants that live above their roots, but also live from dead plants. If they have experienced death, they provide input to the living plants, even though they are the fauna of another. Land fauna is one group of heterotrophs living creatures outside plants and bacteria, whose lives depend on the availability of the main producer living creatures in the soil.
Soil fauna is an organism that is partly or whole-life cycle spent in the soil (Kimmins 1987). Suhardjono and Adisoemarto (1997) state that arthropods of land are all groups of animals that part or all of their life cycles depend on the land because the source of feed is present in the soil. The soil fauna consists of macrofauna, mesofauna and microfauna (Kimmins 1987). The existence of soil fauna in the soil is highly dependent on the availability of energy and food sources for its life, such as organic matter and living biomass which are all related to the flow of the carbon cycle in the soil. However, the process of decomposition or decomposition in the soil will not be able to run quickly if not supported by macrofauna activities.
The nutrients that are expelled from decomposed leaves and wood usually do not move directly into the soil or tree roots, but will pass through all the cycles between the organic material part of the soil. In the process of leaf decomposition, the cycle often works with ground arthropods that chew the leaves. When the nutrients pass through the artrophoda digestive system, the complex organic compounds are converted into simple compounds ready for use by other soil organisms.
Leaf and wood decomposition can also be initiated by tissue invasion by fungi and bacteria. This organism quickly stops many of the soluble cations in the tissues and changes the nature of the substrate. Sometimes it keeps it more resistant.