Relative efficiency of zinc oxide and zinc sulphate-enriched urea for spring wheat

Field experiments conducted at the Indian Agricultural Research Institute, New Delhi during 2005-2007 showed that the application of small amounts of zinc (Zn) in the form 0.5-2.0% of Zn-enriched urea significantly increased yield attributes, grain and straw yield, Zn concentrations in the grain and straw and Zn uptake by spring wheat. The agronomic and crop recovery efficiency of applied Zn decreased as the level of Zn-enrichment was increased from 0.5 to 2%. Zinc sulphate (ZnSO4) and zinc oxide (ZnO) were equally effective in increasing the grain yield of wheat. Based on these results, we recommend the application of a 0.5-1.0% Zn enrichment of urea with ZnSO4 or a 1.0% Zn-enrichment with ZnO.