Farm business3 min read
Turn cow dung into money: compost, vermicompost and biogas
Every cow produces a lot of dung each day. Handled well, it becomes fertiliser, cooking gas and extra income instead of smell and flies. Three practical options compared.
An adult cow produces roughly 10–20 kg of fresh dung a day, depending on its size and feed. On a farm with five cows, that is more than a tonne a month. Left in a heap, it smells, breeds flies, loses most of its nutrients to rain and sun, and annoys the neighbours. Managed properly, it can feed your crops and fodder, cook your food and even bring in cash.
Option 1: Simple compost pit
The cheapest start.
- Dig a pit (for example 2–3 m long, 1–1.5 m wide, about 1 m deep) on high ground, under a roof or a cover so rain doesn't wash it out.
- Add dung in layers, mixing in straw, leftover fodder and leaves.
- Keep it moist but not wet, like a squeezed sponge.
- Turn the heap every few weeks to let air in.
- In about 2–3 months it becomes dark, crumbly compost that smells of soil.
Use it on your Napier and fodder plots, vegetables and fruit trees. Well-rotted compost is better than fresh dung, which can burn young plants and carries weed seeds.
Option 2: Vermicompost (earthworm compost)
Vermicompost is finer and richer than ordinary compost, and many vegetable and nursery growers buy it.
- Use red composting earthworms (often sold as "red wigglers", Eisenia fetida), not ordinary soil earthworms.
- Use dung that is a few weeks old (fresh dung heats up and can kill the worms).
- Keep the bed in shade, in a cement ring, tank or brick bed with drainage; cover it with sacks.
- Keep it moist; protect it from ants, rats, birds and flooding.
- In about 45–60 days the top turns into dark, granular vermicompost. Stop watering for a few days, collect the top layer, and sieve it.
- Separate the worms and use them to start new beds; extra worms can be sold too.
Option 3: Biogas plant
A biogas plant turns dung into cooking gas and leaves a liquid slurry that is an excellent fertiliser.
- A small family plant often needs the dung of about 3–5 cows a day, mixed with an equal amount of water.
- It can provide cooking gas for a family every day, replacing firewood, LPG cylinders or dung cakes, which means less smoke in the kitchen.
- The slurry can go straight onto fodder fields or into the compost pit.
- Building a plant costs money up front, so ask your upazila livestock or agriculture office, or local development organisations, whether a support or loan programme is available in your area.
Which one is right for you?
| Compost pit | Vermicompost | Biogas | |
|---|---|---|---|
| Start-up cost | Very low | Low | Medium to high |
| Work | Turning now and then | Daily care of the bed | Daily feeding with dung and water |
| Product | Compost | High-value vermicompost + worms | Cooking gas + slurry fertiliser |
| Best for | Every farm | Farms that can sell to vegetable growers or nurseries | Farms with 3+ cows and a family kitchen nearby |
Many farms combine them: biogas for the kitchen, slurry and extra dung to compost or vermicompost, and the fertiliser on fodder plots.
Health and neighbours
- Keep dung heaps and pits away from wells, ponds and the house.
- Cover them to reduce flies and smell.
- Wash hands after handling dung.
Count it as income
Sales of compost, vermicompost or worms, and the money you save on gas and fertiliser, are real income from your farm. Record them in FarmFlows → Finance as income so your farm's profit report shows the full picture.
Quick checklist
- 10–20 kg of dung per cow per day: don't waste it
- Compost: covered pit, layers, moist, turned, ready in 2–3 months
- Vermicompost: red worms, partly rotted dung, shade, 45–60 days
- Biogas: dung of 3–5 cows for a family plant; slurry as fertiliser
- Record sales and savings as income