Turning farmyard manure into compost that actually works
Most heaps in the village are not composting. They are drying out. The difference is four turns, a carbon source and about ninety days.
Walk past most farmyard manure heaps in August and you will find a crust on the outside, dust in the middle and a smell of ammonia coming off the top. That heap is not composting. It is losing nitrogen to the air and moisture to the sun, and what finally goes into the field is about a third of the fertiliser value that was standing there in May.
Composting is a controlled process with four things to get right. Miss any one and the heap stalls.
Compost needs a carbon-to-nitrogen ratio near 30:1
Fresh dung and urine-soaked bedding are nitrogen-rich — roughly 15:1. On their own they go anaerobic, turn slimy and stink. Dry crop residue is the correction: paddy straw sits around 80:1, wheat straw near 100:1, sugarcane trash higher still.
A working recipe by volume, not weight:
- Three parts dung and bedding
- Two parts chopped dry residue, cut to under 10 cm
- A handful of old finished compost per layer, as inoculum
Chopping matters more than farmers expect. Whole straw traps air pockets that never heat, and it is still recognisable at ninety days.
Build a compost windrow, not a pile
A heap under one metre high cannot hold its own heat and will not reach thermophilic temperature. Over two metres, the core goes anaerobic under its own weight. Build a windrow 1.5 m high, 2 m wide at the base, and as long as the material allows. Site it in shade if you have it, and dig a shallow trench around it so runoff after a shower does not carry leachate into the field drain.
Hold moisture at the squeeze test
Take a fistful from 30 cm inside the windrow and squeeze. It should feel like a wrung-out cloth — damp, holding shape, releasing at most a drop or two. Bone dry stops the process; dripping wet drowns it.
Through the hot weeks that means watering the windrow at every turn, not sprinkling the surface daily. Surface water evaporates before it reaches the core and does nothing except grow a crust.
Turn on temperature, not on the calendar
Push a bamboo stake into the core and pull it out after ten minutes. If it is uncomfortably hot to hold against the wrist, the windrow is above 55°C and working. When the stake comes out merely warm, the easy carbon is used up and it is time to turn.
| Stage | Day | What you should find |
|---|---|---|
| Heating | 2–5 | Core too hot to hold, visible steam at dawn |
| First turn | 10–14 | Outer material still recognisable, move it to the centre |
| Second turn | 25–30 | Temperature climbs again, but lower than the first peak |
| Third turn | 45–55 | Straw breaking, colour going dark |
| Curing | 60–90 | Near ambient temperature, earthworms move in |
Four turns over three months is the whole labour cost. Each turn moves the cool outside material into the hot centre, which is what actually kills weed seed and pathogens — not the average temperature, but every part of the heap having spent time in the core.
Two tests before the compost goes on the field
Finished compost is dark, crumbles between the fingers, and smells of wet earth with no trace of ammonia. If you can still identify what went in, it is not ready.
The seedling test settles any doubt. Sow ten mung or radish seeds in a pot of pure compost and ten in a pot of ordinary field soil. If germination in the compost is well below the soil pot, the material is immature and will lock up nitrogen when you spread it. Give it three more weeks.
What to expect from it
Well-made compost runs about 0.8–1.2% nitrogen, 0.4–0.8% phosphorus and 0.8–1.2% potassium, with the organic carbon that a soil test almost always shows as the real deficit. At 5 tonnes per acre it will not replace a fertiliser programme in the first year. Over three or four seasons of steady application, on land that has had nothing but urea, the change in water-holding capacity alone will show up in a dry fortnight.
Further reading: the Indian Council of Agricultural Research publishes crop-wise packages of practice that include compost rates by soil type.
