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Choosing organic fertiliser: look at composting, salt and the C:N ratio

The cartoon on the bag is not a test.

Thin organic matterFertiliser burn
Speed
  1. The bag says organic; some still burn the hand and stink; some are salty.
  2. Houses must ask salt.
  3. Bag fertiliser has a clear salt number; dirty organic manure hides salt and ammonia.
  4. A house and a meal first, then the inoculant can live. Raw dung plus inoculant cooks the workers.
  5. Don’t call raw dung rotted; don’t high-rate a house without a salt check.
  6. What “rotted” means: Does not burn the hand, no sharp ammonia, a dark colour. If you cannot reach that, don’t go in
  7. Name what you see before you feed.
  8. If leaves, roots and the surface disagree, stop.

What you see in the field

The bag says organic; some still burn the hand and stink; some are salty. Houses must ask salt.Rub a handful next to a darker neighbour that still forms crumbs. Pale dusty soil that leaks after rain matches this page. Yellow leaves are extra — first ask whether the soil still has body.

A sketch. Do not fertilise from the picture alone.

Tap to enlarge. The caption says what to photograph. Missing field photos are marked as to-be-added.

Why it looks like this

The field looks like this because the root cannot take water or nutrients the usual way. Fix the soil condition first — drainage, salt, acidity, compaction or a salt of fertiliser — then a thin feed. Rates live in the range on this page; confirm with a local station and the label.

Easy to mix up

  • Looks like “Bag fertiliser”

    Bag fertiliser has a clear salt number; dirty organic manure hides salt and ammonia.

  • Looks like “A microbial product”

    A house and a meal first, then the inoculant can live. Raw dung plus inoculant cooks the workers.

Do this / don’t do that

  1. 1Compare the worst plants with a neighbour ridge. Photograph whole plant, close-up and soil surface before you add fertiliser.
  2. 2Match roots, leaves and the soil surface to this guide. If they do not line up, do not copy a bag count.
  3. 3Use the rate range on this page only as a range. Confirm with a local station and the product label.

Don’t do this first

  • Don’t call raw dung rotted; don’t high-rate a house without a salt check.

Rate range

What “rotted” means

Does not burn the hand, no sharp ammonia, a dark colour

If you cannot reach that, don’t go in.

Salt

Stricter in a house

Ask for a test, or try a small patch first.

These are ranges. Confirm with your local extension station and the product label.

EC (fertiliser)

Whether it will burn the root

Houses need it stricter.

Water / temperature

Rotted, or not

If it burns the hand, it is still cooking.

When you see The bag says organic; some still burn the hand and stink; some are salty. Houses must ask salt, test. Take soil from the bad patch and from a greener neighbour, separately.

Lesson video

2026-03-03 · Li Zeyu · For learning. Serious damage: local agronomist or a soil test.

For learning only. Fertiliser and pesticide decisions need a local agronomist and a soil test.

Not sure? Photograph the field to identify the problem