5.7 What are the characteristics of FS-based vermicompost and how does it compare to compost?
Vermicompost is a heterogeneous mixture of decomposing organic waste (at various stages of decomposition), bedding materials, and vermicast. Vermicast is the material produced by earthworms as a result of their digestive processes, also known as worm castings or worm faeces. Thereby, vermicast in particular is the nutrient-rich and beneficial microorganisms containing part of vermicompost.
Earthworm castings in a home garden often contain 5 to 11 times more nitrogen, phosphorous, and potassium than the surrounding soil. Secretions in the intestinal tracts of earthworms, along with soil passing through the earthworms, make nutrients more concentrated and available for plant uptake, including micronutrients. Worms in vermicompost act in a similar fashion, breaking down organic wastes into nutrient-rich compost. The amount of nutrients in vermicompost is often higher than in traditional compost.
An example of vermicompost quality produced from faecal sludge in India and vermi co-composting of organic waste with faecal sludge in Bangladesh achieved in experiments is provided in the table below.
| Parameter | Unit | Vermicompost FS India | Vermicompost FS+OW Bangladesh | Compost Standard of Bangladesh |
|---|---|---|---|---|
| pH | 8.0 | 8.1 | 6 – 8.5 | |
| Moisture | % | 43 | 20 | ≤20 |
| TN | % | 2.8 | 1.8 | 0.5 – 4.0 |
| TP | % | 2.4 | 1 | 0.5 – 1.5 |
| Total Coliform | cfu/g | <3.6 | 100 | – |
| Cu | % | – | – | ≤ 0.05 |
| Zn | % | 0.05 | – | ≤ 0.1 |
| Cd | ppm | – | – | ≤ 5 |
| Cr | ppm | – | – | ≤ 50 |
| Pb | ppm | – | – | ≤ 30 |
| Ni | ppm | 0.02 | – | ≤ 30 |
| Mg | ppm | 19.5 | – | – |
| Fe | ppm | 8 | – | – |
| Organic Carbon | % | 17.5 | 18.7 | 10 – 25 |
| C:N | 6.5 | 10.5 | ≤ 20:1 | |
| K | % | 6.5 | 1 | 1 – 3 |
| S | % | – | – | 0.1 – 0.5 |
For further information, please click on the Materials tab at the top of the page.
