Introduction
Composting is an ancient practice of organic fertilization widely used in agriculture and gardening. It involves the biological breakdown of biomass into humus, which enhances the physical and chemical properties of soil. As humus continues to decompose, it gradually releases essential nutrients that support plant growth. Composting depends on various organisms that feed on biomass, breaking it down into finer particles and simpler compounds. The resulting compost can be effectively used to maintain and improve soil fertility.
Earthworms and microorganisms naturally decompose dead organic matter. When earthworms are deliberately introduced into a biomass heap to accelerate this process, it is referred to as vermicomposting. Vermicomposting is a sustainable technology that uses earthworms to convert organic waste into nutrient-rich compost. This vermicompost serves as a healthy alternative to chemical fertilizers and is especially suitable for plantation crops. It contains nutrients in forms readily available to plants. Earthworms accelerate the decomposition process, enhance soil structure, and promote beneficial microbial activity.
- Objectives
- To enhance the composting process by adding Panchagavya and other admixtures.
- To compare the composting of yard waste with and without the addition of earthworms.
- Literature Review
Organic residues are increasingly considered valuable resources rather than waste to be landfilled or incinerated. Solid waste management encompasses a wide range of practices for handling solid, liquid, and gaseous wastes. Vermicomposting is a recycling technology that improves the quality of compost.
Earthworms are generally classified into two types:
- Burrowing types: Perionyx elongata and Perionyx asiatica, which live deep in the soil.
- Non-burrowing types: Eisenia fetida and Eudrilus eugeniae, which live in the upper soil layers.
Various parameters—such as pH, electrical conductivity, C/N ratio, and concentrations of nitrogen (N), phosphorus (P), and potassium (K)—can be measured at different stages of composting to monitor quality. Studies have shown that nutrient content increases significantly by the 45th day of composting. Additionally, microbes present in Panchagavya secrete enzymes and plant growth hormones that promote plant development.
- Collection of Yard Waste
Yard waste was collected from the SRM University campus and nearby areas. The lush greenery on campus produces large quantities of waste from routine cutting and trimming. Equal amounts of green and dry waste were collected—about 250 kg each. The dry waste consisted mainly of shredded wood chips and dried plant material. This mixture helps maintain an appropriate carbon-to-nitrogen ratio and partially decomposed matter accelerates the breakdown of organic waste.
- Preparation of Panchagavya
Panchagavya is a traditional bio-enhancer prepared from five cow-derived products. The three primary components are cow dung, urine, and milk, while the two secondary products are curd and ghee.
To prepare Panchagavya, 5 kg of fresh cow dung is placed in a large container and mixed with 3 liters of cow urine and 2 liters of milk. To this mixture, 1 kg of ghee and 1 liter of curd are added, followed by thorough mixing. The mixture is then diluted with 10 liters of water. The quantity of Panchagavya used depends on the size of the compost heap, but the ingredient ratio must remain consistent. Panchagavya supports microbial growth, thereby accelerating the composting process.
- Methodology
A slightly elevated and dry area without tree roots was selected for the compost pits. Each pit measured 5 ft × 5 ft × 2 ft and was located away from direct sunlight. A rubber sheet was used to line the pits to prevent the escape of earthworms.
The heap method was adopted for composting. The primary raw materials included fresh green leaves and other yard waste. Green materials, which are rich in nitrogen and decompose quickly, were combined with tougher, carbon-rich dry materials, which decompose more slowly. This combination helps maintain a balanced decomposition process.
- Varieties of Compost Prepared
Six treatments were designed using yard waste and different admixtures. Three treatments used only admixtures, while the other three included both admixtures and earthworms (Eisenia fetida).
- Treatment 1: Yard waste (green + dry) + Panchagavya
- Treatment 2: Yard waste (green + dry) + Panchagavya + green gram mixture
- Treatment 3: Yard waste (green + dry) + Panchagavya + cow dung
- Treatment 4: Yard waste (green + dry) + Panchagavya + earthworms
- Treatment 5: Yard waste (green + dry) + Panchagavya + green gram mixture + earthworms
- Treatment 6: Yard waste (green + dry) + Panchagavya + cow dung + earthworms
Each treatment was allowed to compost for 50 days.
- Experimental Setup
Twigs and dry waste were first cut into small pieces and spread as a 5 cm thick bottom layer to ensure aeration. This was followed by a 15 cm layer of green leaves. Panchagavya solution was sprinkled over the layer before adding the next. A 15 cm layer of dried plant material and a 7.5 cm layer of partially decomposed cow dung were added sequentially, with Panchagavya and water sprinkled between layers to maintain moisture.
This sequence was repeated until the heap reached about 4 feet in height. Proper aeration was ensured as microorganisms need oxygen, and carbon dioxide produced during decomposition must be released. Water was sprinkled daily to maintain adequate moisture. Finally, the heap was covered with a polythene sheet to retain moisture and heat, accelerating decomposition.
After four weeks, the heap volume decreased significantly due to microbial activity. At this stage, the heap was turned to ensure uniform decomposition. Turning involves moving the outer material inward and the inner material outward. This step is essential to prevent incomplete decomposition at the edges. After 40–60 days, the material transformed into mature compost—dark brown in color, crumbly, with a pleasant earthy smell. The compost was then kept covered to protect it from rain.
- Addition of Earthworms
Earthworms reduce waste volume by 40–60% as they consume organic matter. Each earthworm weighs about 0.6–0.8 g and consumes an amount of waste approximately equal to its body weight daily, producing 50–60% of its intake as nutrient-rich castings. Earthworms were sourced from an organic shop in Chennai. A total of 250 g of Eisenia fetida were added to Treatments 4, 5, and 6.
- Micro- and Macro-Nutrient Analysis
The compost samples from each treatment were analyzed for macro- and micro-nutrient content at the Department of Environmental Science, Analytical and Advisory Unit, Tamil Nadu Agricultural University.
- Organic carbon
Organic carbon content (%) is highest in Treatment 5, in this treatment compost is prepared from the yard waste (greenwaste+drywaste) with bacterial booster (panchakavya) and nutrient booster (green gram) admixtures with addition of earthworms, and the duration of composting was 50 days.
The nutrient content of sample organic carbon is found to be 12.68% in treatment.
Figure 1.1 Organic Carbon
- Total nitrogen
Total nitrogen content (%) is highest in Treatment 4, in this treatment compost is prepared from the yard waste (greenwaste+drywaste), panchakavya is added as bacterial booster with addition of earthworms and the duration of composting was 50 days. The nutrient content of Total Nitrogen is found to be 0.90% in treatment.
Figure 1.2 Total Nitrogen
- Total phosphorus
Total phosphorus content (%) is highest in Treatment 5, in this treatment compost is prepared from the yard waste (greenwaste+drywaste) with bacterial booster (panchakavya) and nutrient booster (green gram) admixtures with addition of earthworms and the duration of composting was 50 days.
The nutrient content of sample Total Phosphorus is found to be 0.54% in treatment.
Figure 1.3 Total Phosphorous
- Total potassium
Total potassium content (%) is highest in Treatment 6, in this treatment compost is prepared from the yard waste (greenwaste+drywaste) with cow dung, and addition of earthworm and the duration of composting 50 days. The nutrient content of sample Total Potassium is found to be 0.90% in treatment.
Figure 1.4 Total Potassium
- Calcium
Organic carbon content (%) is highest in Treatment 4, in this treatment compost is prepared from the yard waste (greenwaste+drywaste), panchakavya is added as bacterial booster with addition of earthworms and the duration of composting was 50 days. The nutrient content of sample Calcium is found to be 470 (Mg/Kg) in treatment.
Figure 1.5 Calcium
- Magnesium
Magnesium content (%) is highest in Treatment 4, in this treatment compost is prepared from the yard waste (greenwaste+drywaste), panchagavya is added as bacterial booster with addition of earthworms and the duration of composting was 50 days. The nutrient content of sample Magnesium is found to be 132 (Mg/Kg) in treatment.
Figure 1.6 Magnesium
- Zinc
Zinc content (%) is highest in Treatment 4, in this treatment compost is prepared from the yard waste (greenwaste+drywaste), panchagavya is added as bacterial booster with addition of earthworms and the duration of composting was 50 days. The nutrient content of sample Zinc is found to be 37.5 (Mg/Kg) in treatment.
Figure 1.7 Zinc
RESULTS AND DISCUSSION
The net overall efficiency of N, P, and K is considerably greater in the treatment with earthworms than that of the treatment without earthworms. Thus the result indicates that the nutrient content present in treatment 4, 5, 6 is maximum compared to the treatment which is without earthworms. The nutrient values derived from this study are given in the table below.
Table 1.1 Compost Nutrients Analysis
| S. No. | Parameters | T1 | T2 | T3 | T4 | T5 | T6 |
| 1 | Organic carbon (%) | 11.25 | 12.38 | 11.50 | 11.55 | 12.68 | 11.80 |
| 2 | Total nitrogen (%) | 0.65 | 0.58 | 0.50 | 0.90 | 0.83 | 0.75 |
| 3 | Total phosphorus (%) | 0.20 | 0.24 | 0.20 | 0.50 | 0.54 | 0.50 |
| 4 | Total potassium (%) | 0.50 | 0.45 | 0.60 | 0.80 | 0.70 | 0.85 |
| 5 | Calcium (mg/kg) | 450 | 312 | 415 | 480 | 342 | 440 |
| 6 | Magnesium (mg/kg) | 112 | 80 | 94 | 137 | 110 | 120 |
| 7 | Zinc (mg/kg) | 32.50 | 28.90 | 30.50 | 37.50 | 32.90 | 35.50 |
CONCLUSION
This study demonstrates that pre-digestion or partial pre-decomposition of yard waste leads to improved vermicompost production. Shredding yard waste beforehand accelerates its decomposition. Since earthworms are sensitive to excessive moisture and heat, maintaining moderate conditions—specifically around 40–60% moisture content along with adequate shade—is essential. Using woven coconut leaves as a covering provides effective shade and keeps the area cool. The addition of Panchagavya further enhances vermicompost production when using composting worms such as Eisenia foetida.
High-quality compost was obtained, and the preparation time varied depending on the type of admixture used. Compost was typically ready within 50 to 70 days, with a recovery efficiency of about 65–70%. While vermicompost made solely from cow dung is nutrient-rich, it is less economical. Combining partially decomposed yard waste with cow dung produces higher yields at lower costs. The resulting compost contains readily available forms of phosphorus, potassium, nitrates, calcium, and magnesium, all of which enhance soil fertility.
In addition to supplying nutrients, compost improves soil structure, allowing greater air circulation and facilitating the uptake of existing nutrients by plants. Improved structure also increases the soil’s moisture retention capacity. Unlike chemical fertilizers, which supply nutrients but do not enhance soil quality, compost enriches the soil and has longer-lasting effects. It is also less prone to being washed away by water. Adopting these composting methods can support efficient waste management practices in both rural and urban areas.
REFERENCES
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- https://en.wikipedia.org/wiki/Panchagavya