Trace element concentrations in the grain of wheat cultivars as affected by nitrogen fertilization

Three winter wheat cultivars were grown under low-N and high-N fertilization rates over two growing seasons. In spite of smaller 1000-grain weight, the high-N fertilization produced higher grain yields as well as grain N and trace element concentrations in both growing seasons. Trace element increments with high-N rate averaged 14.0% for Fe, 9.2% for Zn, 19.7% for Mn, 13.2% for Cu, 15.1% for Ni, and 23.0% for Cd. Only Na concentration was unaffected by N fertilization, whereas Pb and Cr were below detection limits. Absolutely small, but significant differences existed among tested cultivars for all trace elements and these cultivar effects were uniform on both N fertilization rates. However, cultivars differed in their rankings for trace element concentrations across two growing seasons and these specific responses appeared to be closely related to grain N.