Mineral Elements Bioavailability in Milling Fractions of Wheat Grain Response to Zinc and Nitrogen Application

A field experiment was conducted in a high‐yield region in North China to estimate the effect of Zn and N fertilization on mineral element distribution and bioavailability in eight milling fractions of wheat grain (Triticum aestivum L.), which included bran, shorts, break (B1, B2, and B3) and reduction (R1, R2, and R3). The results indicated that foliar Zn decreased Ca and Mn concentration in wheat grain averagely by 4.3 and 6.8%, respectively, but increased Zn by 42.6%. Soil N application improved N, Ca, Cu, Fe, and Zn concentration by 38.9, 10.5, 19.95, 7.0, and 24.4%, respectively. All elements, N, P, K, Ca, Mg, Cu, Mn, Fe, and Zn, were mostly located in bran and shorts. Foliar Zn significantly decreased the accumulation of Mn in bran, shorts, and B2, and increased Zn in each fraction, but did not influence the distribution of Mn and Zn among the eight fractions. Nitrogen application increased the accumulation of all elements in shorts, and altered the distribution in wheat grain. Both measures improved the bioavailability of Zn in B3, R1, R2, and reduction, but did not affect that in bran and shorts. Foliar Zn and N application increased total daily absorbed Zn in flour by 66.0 and 48.9%, and grain by 32.0 and 28.4%, respectively. The concentration of N in wheat grains was positively correlated with Ca, Cu, Fe, and Zn. No correlation was found between Zn and Fe concentration. These results are relevant to agronomic management strategies to improve the element nutrition of wheat grain. Core Ideas Foliar Zn decreases Mn accumulation in bran, shorts, and B2 and increased Zn in each fraction. Soil N application increased accumulation of all elements in shorts, Cu, and Fe in bran but decreased P and K in bran fraction. Zinc bioavailability was higher in break and reduction, and improved by foliar Zn and soil N application. Nitrogen concentration was positively correlated with Ca, Cu, Fe, and Zn in wheat grains. Zinc concentration was not correlated with Fe in wheat grains.