Hard soil: a shiny pan the roots will not cross
After rain a slurry, when dry a cap. Look at twenty centimetres before you feed.
- Try the hoe: slurry after rain, brick when it dries.
- Seedlings wear a cap.
- Roots run sideways.
- Dig twenty centimetres and look for a shiny pan.
- Wheel ruts often stay bare.
- Wet footprints sink deep — keep the tractor off.
- Drought is no water. Compaction is water that cannot enter. It runs off.
- The whole layer hard is compaction. A shiny ribbon underneath is the pan.
- Ponding after rain, a cap when dry, a shiny pan under twenty centimetres — three different notes.
- Don’t drive on mud.
What you see in the field
Try the hoe: after rain a slurry, when dry a cap that bounces the blade. Seedlings wear a cap of soil; roots run sideways. Dig a pit in the wheel track and look at about twenty centimetres for a shiny, knife-cut pan. When footprints sink deep, keep machines off. Compare a ridge you can still hoe with the one that bounces. Compaction blocks the root’s path; it is not simply a shortage of fertiliser.
Tap to enlarge. The caption says what to photograph. Missing field photos are marked as to-be-added.
Why it looks like this
Repeated traffic, wet tillage and thin organic matter flatten aggregates and close pores. Roots hit the pan and turn sideways. Machines on wet soil make a plough pan. Subsoiling only when the soil cracks instead of smearing; wet soil polishes the pan.
A sketch. Do not fertilise from the picture alone.Easy to mix up
Looks like “Drought wilt”
Drought is dry soil that recovers after a soaking. Compaction is still moist, roots run sideways, and water sits on the pan.
Looks like “Saline hard-set”
Saline hard-set often has a crust or mud-then-board. Traffic pans often have no crust and are worst in wheel tracks.
Do this / don’t do that
- 1Keep machines off wet soil. Deep prints polish the pan and make the next loosening harder.
- 2Dig a pit and look at about twenty centimetres for a shiny pan. Subsoil only when the soil cracks instead of smearing, and only through that layer.
- 3Follow with rotted organic matter to keep pores. One wet, deep inversion will polish the face again.
Don’t do this first
- Do not drive on wet soil.
- Do not subsoil a slurry.
- Do not chase compaction with more fertiliser.
Rate range
| Crop × texture | Texture | Rate | Note |
|---|---|---|---|
| Wheat / maize / vegetables | Clay | Deep-loosen 25–40 cm, every other year, just through the pan | Right moisture only; follow with rotted organic matter |
These are ranges. Confirm with your local extension station and the product label.
| Cell | Low | Mid | High |
|---|---|---|---|
| Bulk density | Open enough | Watch traffic | Packed |
| Organic matter | Glue is gone | Holds crumbs | Buffers traffic |
One number example
Wheel tracks that take a deep print after rain and grow no seedlings: stop machines, wait until the soil cracks, then subsoil the pan at about twenty centimetres. One wet, deep inversion will polish it again. Follow with rotted organic matter.
Sample above and below the pan. Don’t mix them in one bag.
Lesson video
2026-03-28 · 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