Crop development
Poor emergence in cotton and maize: thin, patchy stands
Seedlings on the field are thin or patchy compared with the crop's norm and with nearby fields sown at the same time. Yield depends heavily on how much light the crop intercepts from the first weeks. A thin stand cannot catch up: the yield ceiling is set before the rows close.
Crops: Cotton, Maize
When it is dangerous
Germination and emergence decide the outcome: this is when plant density for the whole season is set, and the last window when resowing is still possible. Once the rows close, the problem can no longer be seen in imagery. Wide-row crops such as cotton and maize are most exposed, especially on the saline soils of the Aral Sea region and Karakalpakstan.
Causes
- Soil crust
- Soil salinity during germination
- Poor seed or wrong sowing depth
- Cold soil at sowing
Signs on the field
- Thin or patchy seedlings
- Bare soil between plants
- A hard crust on the surface before emergence
- Slow leaf growth across the field
How ClusterOS notices it
From the first cloud-free Sentinel-2 image after the expected emergence date, ClusterOS compares the field's greenness with fields of the same crop and sowing date. At 10 m resolution individual plants in a row are not visible, so the satellite does not count plants – it only shows that a field looks suspiciously below normal. Clouds during the short emergence window can hide the problem entirely. Plant density is confirmed by an agronomist's count in the field.
What to do
- When you get a signal, count plants in the field right away – the decision window is short
- Break the soil crust with a harrow
- On saline patches, leach the soil and check the drainage
- Review the sowing practice – seed quality and depth; where the stand is badly thinned, decide on resowing
Questions
Can a satellite count seedling density?
No. Sentinel-2 images at 10 m resolution show only the overall green cover of the field, not single plants. The satellite points to fields that look worse than their neighbours; density is counted in the field.
How is poor emergence different from late sowing?
With poor emergence the field starts greening at the usual time but weakly. With late sowing the green-up is normal but comes later. If there is no green-up at all, the field is fallow or abandoned.
Learn about this risk on your fields before it becomes a loss
We will show ClusterOS on your own fields: history since 2019, crop stage and all 24 risks.
Other risks in «Crop development»
Scientific basis
- Monteith J.L. (1977) Phil. Trans. R. Soc. Lond. B 281(980):277–294, DOI: 10.1098/rstb.1977.0140
- Sinclair T.R., Muchow R.C. (1999) Advances in Agronomy 65:215–265