Compost is organic matter made of mainly plant materials that have decayed. Compost manure supplies soil with both macro and micronutrients. Inorganic fertilisers often provide a few nutrients per product. Therefore, for more sustainable production, compost works well.While plant materials and other organic waste can decompose naturally and get incorporated into the soil, composting hastens the process. It also builds soil structure through the addition of humus, enhances moisture absorption and retention, and reduces soil erosion.Composting utilises all available organic materials – Brown materials, including dried plant residues, grass, leaves, maize stover, and so on, green plant materials such as kitchen waste and green plants, and animal manure.
There are two main ways of composting: Heap and pit.
The difference between a compost heap and pit is that a heap is done on the ground surface, while a pit is dug 2-3ft in the ground.
Pit composting is suitable in areas with less rainfall/water, as it helps to conserve moisture. The heap method is suitable in areas with significant rainfall, as it prevents logging/excess water entering the compost, which would affect the process.
Apart from the location of the pit or heap, the rest of the steps for composting are the same for both methods.
What you need to do
1. Select the best method that will suit your prevailing/current weather.
2. Select the site for your compost pit. Select a site that is not exposed to wind, rain/runoff – preferably where the compost material is not exposed to direct sunlight. Choose a site close to where the compost manure will ultimately be used to reduce the hassle of moving it.
3. Establishing a compost heap/pit
For pit composting, avoid digging the pit deeper than 2-3ft, as this may result in the materials placed deep in the ground not decomposing properly. This is because, some microorganisms cannot survive under such circumstances.
The compost site should always be 1-1.5m wide and can be as long as needed based on available material for composting. This width enables you to easily turn the material as you can reach the entire width of the pit/heap.
The compost pit can be smeared with fresh cow dung to reduce leaching of nutrients. The heap on the other end is supported by small poles and droppers around it on both corners to ensure that it is stable.
3. Make the compost layers
The foundation layer: This is the layer that sits at the very bottom of the heap or pit of the compost. It includes larger plant materials (dry) such as dried maize stalks, grass, dried leaves, and so on. Cut the materials into small pieces and spread them until they are about 25cm high from the base. Sprinkle some water on this layer – ensure the material is MOIST but not WET.
The first layer: This includes green plant materials such as green grass cuttings, kitchen waste and other green planting materials. It is recommended to include shrubs such as tithonia (Mexican sunflower), glyricidia, leucaena, sesbania, crotalaria and lantana to increase the Nitrogen content. Apply this up to about 30cm.
The second layer: Includes animal manure. Also, add slightly decomposed manure to introduce microorganisms to the compost for faster decomposition. The animal manure may be mixed with some soil. Apply this up to 20cm only to allow for good air penetration.
Cover layer: Add a cover layer with either banana leaves or other broad leaves or polythene cover to prevent exposure to rain, direct sunlight and animal disturbance.
4. Check the site every two weeks for temperature and moisture. This is done by inserting a stick in the centre of the heap. Feel the stick with your fingers to get the temperature and moisture. If the composting is going on well, the stick will be moist and warm.
If the compost is not moist, sprinkle some water evenly as you turn it. Add enough water to make the material moist – not wet. High temperatures can be corrected by suspending the cover for a while to allow the hot air to escape. Low temperatures mean slow composting and can be corrected by adding covering and allowing sunlight to reach the heap, so it can be heated up.
5. Turn the compost after three weeks and add some water to make it moist (only when necessary).
6. Your manure should be properly composed within six weeks. You will be able to tell from the sweet smell it produces and the uniformity of the final material.