> ## Documentation Index
> Fetch the complete documentation index at: https://badixth-dc85e378.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Diagnose and Respond to Iron Toxicity in Rice

> Identify iron toxicity in paddy from bronze-orange stippling on lower leaves in acid, waterlogged, or reduced soils, and reduce damage with drainage, lime, and tolerant cultivars.

Iron toxicity is common on acid sulfate soils, low-lying valley bottoms, and inland valleys with prolonged flooding. Under strong soil reduction, iron becomes soluble at concentrations that damage rice roots and leaves. It is a *toxicity*, not a deficiency, and it responds to water and pH management more than to fertilizer.

## When rice is most vulnerable

From seedling establishment through early tillering. Severe iron toxicity can kill young plants; moderate cases stunt tillering and cap final yield.

## How iron toxicity shows in satellite data

* **Low, patchy NDVI** in low-lying zones and toe-slopes where water accumulates and stays reduced.
* Same zones affected season after season, closely correlated with elevation and drainage.
* Signature overlaps with poor soil, submergence, and salinity - use soil pH, standing water depth, and the bronze leaf color on the ground to separate them.

## Field symptoms

* Tiny brown to bronze-orange stipples on lower leaves, spreading and coalescing into a bronzed appearance
* Purplish-brown streaks along the leaf blade in some cultivars
* Stunted plants with limited tillering and dark, blackened, sparse root system
* Yellow-orange discoloration in severe cases, mistaken for tungro or N deficiency
* Affected patches follow topography (low spots, water-collecting zones)

## Reduce the damage by

* **Improve drainage** - alternate wetting and drying reduces soil reduction and iron solubility.
* **Delay transplanting** by a few weeks on affected fields to let reduction subside after initial flooding.
* **Apply lime** on acid soils (pH below 5.0) to precipitate iron.
* **Use iron-toxicity-tolerant cultivars** such as those released from Africa Rice and IRRI screening for iron-toxic environments.
* **Balance nutrients** - adequate P, K, and Zn reduce the severity of iron toxicity symptoms.
* **Do not confuse with brown spot or tungro** - confirm with soil pH and water history.

## Set an alert for early warning

<Tip>
  Turn the diagnosis into a trigger. Go to the [Alerts](/guides/alerts-notifications) page and configure a rule so low-lying iron-toxic zones are flagged within weeks of transplanting.
</Tip>

Recommended settings for iron toxicity on rice:

* **NDVI threshold alert** on flagged low-lying zones at 14 to 30 days after transplanting.
* **Seasonal review** - iron toxicity is chronic and zone-specific; combine alert data with a [prescription map](/guides/prescription-maps) for zone-specific drainage and cultivar planning.

## Related

* [Rice Diagnosis](/guides/Crop/Rice/rice-abiotic-stress)
* [Rice: Poor Soil](/guides/Crop/Rice/rice-abiotic-stress/rice-poor-soil) - overlapping cause on weathered acid soils.
* [Set up automated crop alerts](/guides/alerts-notifications)