Decomposition and compostingSpec 9.18B
Composting uses decomposers to break down plant material and waste into compost, which returns nutrients to the soil. Here the aim is to make decomposition fast, so the conditions are the opposite of food preservation.
- Temperature: warm, because the enzymes of decomposers work faster as temperature rises, up to an optimum. Very high temperatures denature enzymes.
- Water content: moist, because decomposers need water. Too dry slows decomposition, and waterlogged material has little air.
- Oxygen availability: well aerated, for example by turning the heap, so that decomposers can respire aerobically. With little oxygen decomposition is much slower.
Many gardeners turn the compost heap regularly and keep it moist but not soaked.