Diagnosing iron deficiency in narrow-leafed lupins
Lupin crops grown on fine-textured, alkaline soils that become saturated with water in winter will usually show bright yellowing of young leaves that is typical of iron deficiency.
What to look for
- Smaller paler plants with chlorotic new leaves.
- Deficiency is most likely in deep pale or limed sands, and in waterlogged areas.
Paddock
- Young leaves and new growth become yellow over the whole leaf.
- As deficiency often occurs in wet conditions, brown leaf spot lesions on leaves may also be be present.
- Middle leaves of severely deficient plants may shrivel back towards the base of the leaflet
Plant
What else could it be
| Condition | Similarities | Differences |
|---|---|---|
| Diagnosing sulphur deficiency in narrow-leafed lupins | Pale small new leaves | Deficiency is mainly on poor sands rather than wet soils. |
| Diagnosing group B herbicide damage in narrow-leafed lupins | Pale small new leaves | Plants die back from growing point |
| Diagnosing zinc deficiency in narrow-leafed lupins | Stunted plants with pale new leaves | New growth is rosetted and iron deficiency is mainly on wet soils. |
Where did it come from?
Soil type
Temperature
- There are a complex series of interactions in the soil that combine to reduce the availability of iron to lupins. The deficiency will usually occur in lupin grown on soils with a pH above 7.0 if the soil aeration is reduced slightly and temperatures are cold.
Management strategies
Spraying foliar
- No yield responses to iron have been measured in the field to justify soil application.
- Foliar sprays will remove the symptoms where they occur in highly calcareous or limed soils
- Where symptoms occur, particularly in cold and wet conditions, they are frequently eliminated by increased soil and air temperatures.
See also
Further information
Where to go for expert help
Page last updated: Wednesday, 6 May 2015 - 11:24am