OCCURRENCE OF PHYSIOLOGICALLY INACTIVE ZINC IN MAIZE ON A BLACK EARTH SOIL

Physiologically inactive Zn occurred in the tops of both Zn-inefficient and Zn-efficient maize cultivars when grown in pots on a black earth soil. The conditions was not caused by P/Zn, Fe/Zn, Cu/Zn or Mn/Zn imbalances, but was associated with marginally deficient B levels. P fertilization intensified the condition producing a P/Zn imbalance in both cultivars, possibly combined with a Cu/Zn imbalance in the inefficient cultivar and Fe/Zn, Cu/Zn and Mn/Zn imbalances in the efficient cultivar. Plant analysis was inadequate as a measure of Zn deficiency under these conditions.