Studies on Transformation and Nutrition of Zinc in Alfisol

The distribution of applied zinc in various pools of Zn in an Alfisol soil of Tamil Nadu was found in the order: water soluble < exchangeable < organically bound < complexed < HCI extractable. The amount of water soluble, exchangeable and complexed forms of Zn diminished due to crop removal, while organically bound and HCI extractable were altered to a lesser extent. Addition of Zn to soil increased complexed, organically bound and HCI extractable Zn fractions considerably. Significant and positive correlations amongst different pools of soil Zn point to the existence of a dynamic equilibriwn among the various forms of soil Zn. The organically bound Zn alone contributed as much as 28% and the complexed Zn 24% of the variations in Zn uptake of tomato. All other fractions were found to become available through organically bound and complexed Zn forms as shown by path analysis.