Manganese (Mn) deficiency has been diagnosed in highly alkaline Esperance mallee soils that are also susceptible to Mn deficiency in cereals.
What to look for
Paddock
Early symptoms are pale new leaves with interveinal chlorosis that varies with variety.
Plant
In dun type varieties, new leaves become puckered and narrowly cupped with necrotic tipping on leaves and tendrils.
In white seed varieties, affected leaves curl downwards along the length of the leaf . Interveinal leaf chlorosis turns into necrotic light brown spotting. Tendrils on new leaves have pale and excessively curled ends.
Management strategies
Spraying foliar
A foliar spray will correct the deficiency.
Mn fertiliser is effective but expensive as high rates and several applications are required to generate residual value.
Seed Mn coating treatments have little effect in correcting deficiency
How can it be monitored?
Whole plant tests, are not reliable enough to determine deficiency.
Concentrations of Mn less than 15 mg/kg in youngest mature leaves indicate marginal to deficient levels
Soil tests are not reliable enough to detect deficient soil prior to sowing.
