Effect of Zinc Fertilization on Yield, Enzymatic Discoloration, Phenolic and Nitrogenous Constituents of Potato Tubers

The effect of zinc fertilization on yield, enzymatic discoloration, phenolic and nitrogenous constituents of Katahdin potatoes was studied. Zinc sulfate was banded in the soil at the time of planting at rates of 0, 20, 40, and 100 1b/acre. Application of 100 1b/acre zinc reduced significantly the total yield and especially U.S. #l yields of potatoes, but no significant differences in yield were observed up to 40 1b/acre zinc sulfate. Zinc fertilization significantly reduced phenolic content and discoloration of tubers. Nonprotein nitrogen and free amino acid contents were reduced at all levels of zinc application, and total nitrogen was significantly reduced at the 100 1b/acre level.