Evaluation of Various Zinc Extractants in Lowland Rice Soil under the Influence of Zinc Sulfate and Chelated Zinc

Field experiments were conducted on rice (cv 'IET 4094') in an Aeric endoaquept (pH7.2) to evaluate the various zinc (Zn) extractants in lowland rice soil under the influence of Zn sulfate and chelated Zn. The diethylenetriaminepentaacetic acid (DTPA), 0.1N hydrochloric acid (HCl), and 0.05N HCl-extractable Zn concentrations in soil increased initially up to the Z29 stage of crop growth when Zn was applied as a single basal source, being greater with Zn ethylenediaminetetraacetic acid (Zn-EDTA) compared to zinc sulfate (ZnSO4) application. Among the various extractants, the performance of 0.1N HCl in extracting Zn was better than the other two extractants and followed the trend 0.1N HCl 0.005M DTPA 0.05N HCl. The greatest increase in grain and straw yield of rice was 37.8 and 20.4%, respectively, over the control in the treatment T7 (1kg Zn ha-1 as Zn-EDTA at basal).