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.
- 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
What else could it be
|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?
- 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.
- 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.
Page last updated: Wednesday, 6 May 2015 - 11:24am