Key Points
- While applications of trace element may increase tissue nutrient concentrations, they do notalways result in yield gain.
- Changes in pH can result in changes to the plant availability of some trace elements including manganese (Mn), copper (Cu) and Zinc (Zn).
- An integrated approach to trace element diagnosis takes account of soil, plant tissue and visual indicators for deficiency.
- Recent trials established a reasonably good relationship between yield and tissue manganese levels at ear emergence.
- The work also suggested a critical value of 15 mg/kg in whole plants at early / mid tillering be used to diagnose Mn deficiency.
- Though not observed in these trials, previous work suggested critical values for whole plants at mid tillering were zinc > 12 mg/kg and for copper > 2 mg/kg.