Coir pith composting is an eco-friendly process of converting coir pith, a by-product of the coconut industry, into nutrient-rich organic compost. Coir pith is a spongy material that remains after the extraction of fiber from coconut husks. While it is abundant and has excellent water retention properties, raw coir pith contains high levels of lignin, cellulose, and tannins, making it resistant to decomposition and unsuitable for direct application to soil. Composting addresses these challenges and transforms them into a valuable resource. The coconut husk is composed of short fibers and a mesocarp pith. In the coconut husk, the ratio of coir pith to fiber is 70:30 ( weight by weight basis). About 40-60% of the coconuts produced are used for coir fiber production in India. Every year not less than 0.5 to 1 million tones of coir pith waste is generated in India, which shall be utilized for value addition through converting the coir pith waste into compost.
As the Coir pith holds up to 500% moisture and high porosity it can be used as a soil amendment in coconut farming. Apart from these important physical properties, it contains a high concentration of potash which makes it more useful for coconut. However, the raw coir-pith is toxic to the roots of many crops due to its high content of polyphenolic. Hence, we have to convert the coir pith into nutrient-rich compost to reduce the concentration of toxic phenolics and make the plant nutrients easily available to plants.
There are two methods followed for the production of Coir pith composting. The first one is with the addition of Urea as a nitrogen source and inoculation with microbes( mushroom fungi) and the second one is Urea free coir pith production which is a low-cost, simple, and rapid composting technology based on local resources that can be adopted easily by farmers.
1. How to do composting of coir-pith using mushroom fungi?
The Coir pith possesses a very high C: N ratio and lignin content varying from 30 to 54% which makes it difficult to decompose by microorganisms. To make the coir pith more easy for microbial decomposition, the C: N ratio has to be reduced by the addition of urea. Then incorporate mushroom fungi such as Pleurotus sajor caju, which is a ligno-cellulose degrading organism. However, this technology depends on a regular supply of the mushroom fungal culture for composting the coir pith.
Steps involved in the composting process:
- Preparation of Coir Pith: Soak the coir pith in water to remove excess salts and tannins. Spread the soaked coir pith in a composting area.
- Adding Urea: As a source of nitrogen for microbial activity, Urea @ 1–1.5 kg of urea per ton of coir pith has to be applied. Dissolve the urea in water and sprinkle it evenly over the coir pith to ensure uniform distribution.
- Addition of Microbial Inoculants: Introduce a microbial culture such as Pleurotus sajor-caju (white rot fungi) or other lignocellulolytic microbes. These microbes break down the lignin and cellulose in the coir pith, accelerating the composting process. Mix the inoculant thoroughly with the coir pith.
- Layering and Aeration: Arrange the coir pith and microbial mix in layers to form a heap. Turn the heap periodically (every 7–10 days) to ensure proper aeration, which promotes microbial activity and prevents anaerobic conditions.
- Moisture Management: Maintain the moisture level of the heap at 50–60% throughout the process. This is crucial for microbial activity. Use water if the heap appears dry or cover it during heavy rains to prevent waterlogging.
- Decomposition Period: The composting process typically takes about 6–8 weeks. During this time, the coir pith changes color from dark brown to black, and its texture becomes crumbly. The material loses its raw odor and develops an earthy smell, indicating that it is ready.
- Screening and Storage: Screen the compost to remove any large, undecomposed particles.
2. Urea-free composting of coir pith :
In this method, organic materials with high nitrogen content and low C: N ratio, such as animal manures, are mixed with organic materials having low nitrogen and high C: N ratio, such as coir pith. This mixing of high C: N with low C: N material helps in improved microbial decomposition of the substrates.
The following raw materials are required for this process.
1. Coirpith
2. Poultry manure
3. Lime (Calcium oxide)
4. Rock phosphate
5.Water
- Mix properly 90 kg of coir-pith with 10 kg of good quality poultry manure along with 0.5 kg of lime and 0.5 kg of rock phosphate. Spread the mixture evenly in an area of 2 x 1x 0.5 m in length, breadth, and height respectively
- Sprinkle water regularly using a watering can such that the whole coir pith heap remains sufficiently moist. Overwetting and drying should not take place.
- Cover the heap with a gunny bag greenhouse net or dry grasses to prevent moisture loss.
- Once in fifteen days the whole heap must be turned properly.
- Turning the heap enhances the speed of decomposition indicated by the color change of reddish brown raw coir pith to dark brown color.
- After 45 to 60 days, the coir pith will become dark brown to a black color indicating the completion of the composting process.
Properties of urea-free coir pith compost
The final product possesses a CN ratio of 21 to 22 -and an organic carbon content of 28-30%. The N, P2O5, and K2O content ranges between 1.3 to 1.4, 0.9 to 1.2, and 1.3 to 1.6 %, respectively. It is also a good source of plant micronutrients such as Fe, Cu, Zn, and Mo. The urea-free coir pith compost is rich in plant-beneficial microbes such as free-living nitrogen-fixing and phosphate-solubilizing bacteria. It also has significantly high populations of actinomycetes which are known to produce antibiotics and help in the suppression of soil pathogens.
Advantages of using coir-pith compost
- The coir-pith compost is a good source of manure that improves the physical properties and adds valuable plant nutrients to the soil.
- Enhances water retention, aeration, and microbial activity in the soil.
- Supplies essential nutrients like nitrogen, phosphorus, and potassium to plants.
- Reduces coir pith waste and prevents environmental pollution.
- Provides an economical alternative to chemical fertilizers.
- Coir pith compost is widely used in agriculture, horticulture, and landscaping.
- It increases the organic matter and carbon content of poor humid tropical soils.
It helps in better root formation and enhances crop growth. It is an ideal medium for raising pot-tray seedlings.
