Interactive lesson

Manure, step by step

Interactive lesson: which manure is hot and which is cold, a muck heap without losses, well-rotted manure, intervals before harvest, how much per m² and when to work it in.

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The whole lesson as text

1. Which manure

Manure isn't one thing: every animal gives a different kind.

Cold and hot — Cattle manure with straw is "cold", slow and the safest. Horse manure is "hot": it heats quickly and carries weed seed.
Sheep, goat, chicken — Sheep and goat manure is dry and rich in potash. Chicken manure is very strong: fresh, it "burns" plants, so it always goes via the compost.
What a tonne carries — A tonne of cattle manure carries roughly 5–6 kg of nitrogen, 3 kg of phosphate and 7–8 kg of potash. In the first year the plant gets only 15–25 % of that nitrogen, and 35–50 % from chicken manure.
More bedding — Straw and sawdust soak up urine, and urine carries half the nitrogen and most of the potash. Roughly 2–4 kg of straw per cow a day, and for hens a 10–15 cm layer.

Why: Chicken manure has three times more nitrogen than cattle manure, and sheep manure is dry and heats quickly. That is why they are dosed differently. Real values depend heavily on feed, bedding, rain and the age of the heap.

For larger amounts the most accurate figure comes from a lab analysis of the manure (roughly £30–60 or $25–60).
For large animals count only the months they are housed: at grass, the dung stays on the pasture.

2. A muck heap without losses

A pile on bare ground behind the barn, in the rain, loses much of its nitrogen and potash over a winter.

Base and roof — A concrete pad or well-compacted clay with a fall of 1–2 %, never towards a well. A lean-to or a tarp over the heap, otherwise rain washes out the nutrients.
Walls and dirty water — Walls on three sides, 1–1.5 m high, so the heap is stacked high and tight. The liquid that seeps out is collected in a closed tank or barrel.
Away from the well — At least 30 m (100 ft) from wells and springs (better 50 m), never uphill of them, away from streams, with access for a barrow or tractor.
The tank is dangerous — A dirty-water tank releases ammonia, carbon dioxide and hydrogen sulphide. Never climb into it or lean over the opening. Keep it closed and fenced because of children.

Why: What the rain washes out doesn't disappear: it goes into the stream, the well or the groundwater. A good muck heap saves nutrients and water at the same time.

Nitrate rules usually require storage for at least 4–6 months of manure. In England SSAFO and the NVZ rules, in Ireland the Nitrates Regulations, in the US state rules. Check the rules where you live.
A homestead with one cow (6 tonnes over winter) needs about 5–6 m² of muck heap.