Efficiency of a Zinc Lignosulfonate as Zn Source for Wheat (Triticum aestivum L.) and Corn (Zea mays L.) under Hydroponic Culture Conditions

The objective of this study was to evaluate the efficiency of a zinc lignosulfonate (ZnLS) as Zn source for wheat and corn plants under hydroponic conditions. The Zn-complexing capacity of three commercial lignosulfonates (byproducts of the paper and pulp industry) was tested, and a LS-NH4, from spruce wood, was selected. Its efficacy as Zn fertilizer for wheat and corn plants was assessed at different pH values (7.0 and 8.0) in comparison with a chelate (ZnEDTA) and an inorganic salt (ZnSO4). For wheat at pH 7.0, it was concluded that the efficacy of the Zn fertilizers followed the sequence Zn-EDTA > Zn-LS approximate to ZnSO4 > zero-Zn; and for wheat and corn at pH 8.0, similar results were obtained: Zn-LS > ZnSO4 approximate to 0 Zn. These data give evidence that ZnLS could be used as Zn source to the roots of wheat and corn and seems to be more efficient than ZnSO4 to correct Zn deficiency in both plants.