The Practice of Composting Organic Waste Materials
1. Materials for composting
Materials used for composting should be all organic materials. In general, any type of organic materials that are of plant and animal origin can be used. All non-biodegradable and organic matter containing heavy metals or that can transmit human disease should be avoided.
It is important to use both high carbon-containing materials and high nitrogen-containing materials. This is because different organic matters have different proportions of Carbon and Nitrogen and microorganisms need them both to function well.
In general, young living materials that decompose fast contains a low level of C and high-level N whereas tough, dead materials decompose slowly and have a large amount of C but a low amount of N.
Too little of N – rich material means the composting will be slow whereas too much of it will result in the heap becoming too acidic and smelly. Hence there is a need to have a mixture of materials that have the right proportion of C and N. The table below gives examples of high N and High C-containing materials.
2. Microorganisms
Composting process occurs as a result of the activity of microorganisms and other larger organisms like earthworms and termites. The first condition for composting is the presence of microorganisms. So adding these microorganisms to the compost heap is necessary.
One of the sources of these microorganisms is soil. Thus adding soil to the compost heap will increase the microbial activity of the compost. It is important to collect soils from shady and humid places e.g. from below trees.
Soils that contain moisture also contains microorganism while soils that are dried out by the sun usually do not contain many microorganisms. Decaying leaf litter is also a very good source of microorganisms.
3. Air
The microorganisms in the heap require oxygen to survive and do their work of converting organic materials. The carbon dioxide produced by microorganisms as a result of their activity also needs to be flushed out by the flow of air. If there is no air in the pile the important microorganisms will not survive.
In this situation, only the microorganisms that do not need oxygen will survive and the decomposition of organic material will slow down. In order to get enough air in the heap, do not put the compost heap right against the wall. It is good to put air channels into the heaps.
This can be done effectively done by putting stakes, twigs, straws ,or any other firm material upright in the heap when composting it. The air channel should be removed after 4 – 5 days in order to avoid too much ventilation during fermentation, which can cause combustion.
Read Also: Process of Composting Organic Waste Materials
4. Moisture
Microorganisms need moisture to live and to spread through the heap. The activity of the organism will slow down if the heap is too dry. If it is too wet, then there will be no air and the composting organism will die. This will cause the heap to ferment rather than compost. The moisture level of compost can be tested by putting a straw in the heap.
If after 5 minutes it feels damp, the moisture content is good; but if it dries after 5 minutes, then the moisture is too low. Dry compost has to be sprinkled uniformly with water using a watering can or perforated tin, which ensures uniform distribution of water.
A mixture of urine and water can be used in the ratio of 1:4 because urine can enhance the growth of microorganisms. On the other hand, if a water droplet is observed in the heap, it means the water is too much and the heap should be opened up straight away.
The materials can be allowed to dry up in the sun or can be mixed with drier materials and the heap is made again. If it becomes too wet by rain, then it is better to cover it with a plastic cover. The moisture test is repeated after a few days.
Read Also: Effect of Organic Matter on Soil Physical Properties