Effects of increasing rates of zinc fertilization on phytic acid and phytic acid/zinc molar ratio in zinc bio-fortified wheat

A two-year field trial was conducted to investigate the effect of increasing rates of zinc (Zn) fertilization on Zn accumulation and phytic acid contents in winter wheat (Triticum aestivum L. cv. Yang Mai 16) grown on location without soil Zn deficiency. The rates of ZnSO4·7H2O were as follows: 0 (control), 300, 600, 900, 1200, and 1500 kg/ha, and Zn was added as base fertilizer. The Zn concentrations in different wheat organs were significantly improved and exhibited positive correlations with the Zn fertilizer rates. Phytic acid (PA) concentrations in wheat grains were significantly decreased, and the PA/Zn molar ratio dropped below 15 after Zn application. After harvest, the residual Zn concentrations in the soil were still at high levels with 272.9 mg/kg. According to our results, very high application rates of soil zinc fertilizers (such as 300 kg/ha ZnSO4·7H2O) would be effective for the implementation of Zn biofortification strategy to mitigate Zn malnutrition in human health.