84 / 154
76
GRAANGIDS
2016
GRAIN GUIDE
Macro nutrient element
deficiencies in maize
Nitrogen (N)
• Deficiencies in young plants are usually accompanied by a pale, light yellow-green
appearance.
• In older plants, a characteristic yellowed reverse V shape occurs on the leaves (
Figure 1
).
• The ear shows a characteristic kernel-free sharp point (
Figure 2
).
Phosphate (P)
• Where the soil is very low in phosphate, the leaves, and particularly the edge of the leaf,
develop a characteristic purple colour.
• Phosphate deficiencies occur mainly in younger plants.
Potassium (K)
• Potassium deficiencies in mature plants are indicated by the thin, yellowed edges of leaves.
Sometimes the edges die off.
• Potassium deficiencies usually occur on the lower, older leaves.
• Kernels on the upper part of the ear are poorly filled and appear shrunken.
Magnesium (Mg)
• Magnesium deficiencies usually cause light yellow stripes on the lower leaves, which later
produce a beaded effect with round, dead spots.
• Magnesium deficiencies usually occur in more acidic soils.
• A high potassium content in the soil can induce a magnesium deficiency in the plant,
displaying light-green stripes on the leaf.
Sulphur (S)
• A sulphur deficiency usually displays a light yellowing of the leaves in young plants (
Figure 3
).
Figure 1:
The characteristic
inverted V on a mature maize
leaf that indicates a nitrogen
deficiency.
Figure 2:
Incomplete filling
of an ear of maize due to a
nitrogen deficiency.
Figure 3:
Yellowing of leaves
due to a sulphur deficiency in a
young maize plant.
AA Nel and W Deale: ARC-GCI; Potchefstroom