What it does
Aluminum toxicity in soil inhibits the growth of plant shoots by causing nutrient deficiencies in Magnesium, Calcium, and Phosphorus. It can also lead to drought stress and plant hormone imbalance.
Why and where it occurs
Al toxicity is relatively rare especially in irrigated rice systems.
It rarely occurs in lowland rice except in some soils where soil reduction after flooding proceeds very slowly.
Al toxicity occurs on the following soils:
- Acid upland soils (Ultisols, Oxisols) with large exchangeable Al content. Al toxicity often occurs together with Mn toxicity.
- Acid sulfate soils, particularly when rice is grown as an upland crop for a few weeks before flooding (e.g., Thailand).
- Flooded soils with pH <4 before Fe toxicity symptoms appear.
How to identify
Check for leaf discoloration.
Orange-yellow interveinal chlorosis can be found on leaves.
When severe, discolored areas can die. Yellow to white mottling of interveins is followed by leaf tip death and leaf margin scorch.
Also check for poor stunted growth and deformed roots in susceptible varieties.
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How to manage
To prevent Aluminum toxicity
- Plant tolerant varieties.
- Delay planting until pH has increased sufficiently after flooding (to immobilize Al).
- Provide crops with sufficient water to maintain reduced soil conditions. Prevent the topsoil from drying out.
- Manage fertilizers efficiently.
- Recycle straw or ash in the field to replenish Si removed.
Learn more
View full fact sheet: Aluminum toxicity on IRRI Rice Knowledge Bank