Drought flipping to flood: the root is hurt before the leaf yellows
A drowned-then-baked root looks like a shortage a week later.
- Flood then crack; seedlings wilt then yellow.
- Roots had no time to breathe.
- Yellow after a wet-dry flip often has root injury first.
- A wet-dry flip invites follow-on disease, but save the root first.
- Don’t irrigate wet soil as drought; don’t dump nitrogen the day after a flood.
- Drainage: As soon as you can. The first job
- Name what you see before you feed.
- If leaves, roots and the surface disagree, stop.
What you see in the field
Flood then crack; seedlings wilt then yellow. Roots had no time to breathe.Is the soil wet or dry, the root white or black? Wet wilt and a foul root mean drain first. Leaf wilt with white roots may be drought. Smell the root before you irrigate.
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 “Nitrogen shortage alone”
Yellow after a wet-dry flip often has root injury first.
Looks like “Disease”
A wet-dry flip invites follow-on disease, but save the root first.
Do this / don’t do that
- 1Compare the worst plants with a neighbour ridge. Photograph whole plant, close-up and soil surface before you add fertiliser.
- 2Match roots, leaves and the soil surface to this guide. If they do not line up, do not copy a bag count.
- 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 irrigate wet soil as drought; don’t dump nitrogen the day after a flood.
Rate range
Drainage
As soon as you can
The first job.
Top-dress
A thin feed after new roots show
Heavy feed on a hurt root hurts more.
These are ranges. Confirm with your local extension station and the product label.
When you see Flood then crack; seedlings wilt then yellow. Roots had no time to breathe, test. Mix several spots of the tilled layer; skip the edge and the manure heap.
Lesson video
2026-03-12 · 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