MICRONUTRIENT DEFICIENCIES IN TEAK (<em>TECTONA</em> <em>GRANDIS</em>) SEEDLINGS: FOLIAR SYMPTOMS, GROWTH PERFORMANCE AND REMEDIAL MEASURES

Abstract

SUJATHA, M. P. 2008. Micronutrient deficiencies in teak (Tectona grandis) seedlings: foliar symptoms,
growth performance and remedial measures. Considering the constraints in diagnosing nutrient disorders
encountered in teak seedlings, a study was conducted to induce deficiency symptoms of Fe, Cu, Zn, Mn,
Mo and B and to find out its impact on growth performance and nutrient concentration by adopting
the sand culture technique. According to the results, deficiency of nutrients caused the development of
certain symptoms which were specific to each nutrient. Deficiencies of Mo and Cu caused considerable
reduction in plant height whereas development of healthy new leaves was seriously affected by Fe and B
deficiencies. The order of abundance of micronutrients in teak seedlings was Fe > Mn > Zn > Cu and in
general there was no uniform and definite relation between the concentration of nutrients (except Cu)
and the expression of deficiency symptoms. In the case of Cu, there was a gradual decreasing trend in its
concentration with the expression of deficiency symptoms. Results of the study suggest that total foliar
concentration cannot be used as a reliable indicator in the deficiencies of Fe, Zn and Mn. Trials to rectify
the deficiency symptoms revealed that recovery was fast and easy if the respective nutrients were applied at
the early stage of deficiency. Foliar spray of 0.3% FeSO₄, 1% Bordeaux mixture, 0.1% ZnSO₄, 0.1% MnSO₄,
0.1% MoO₃ and 0.05% boric acid were found to be effective in rectifying the deficiency of Fe, Cu, Zn, Mn,
Mo and B respectively.