Effect of nitrogen and iron fertilizers on grain concentration of iron in wheat

摘要

Greenhouse experiments have been conducted to investigate the effectiveness of various soil- and foliarly-applied iron (Fe) fertilizers in increasing grain Fe concentrations of wheat plants under different nitrogen (N) nutrition regimes. The Fe fertilizers tested were FeS04, Fe-EDTA, Fe-EDDHA and Fe-citrate and applied either into soil or foliar sprayed at the booting and early milk stages. The rates of soil applied nitrogen ranged between 100 to 600 mg N per kg soil. In an additional experiment, plants were also treated with 0.75 % urea during the booting and early milk stages. At a given N supply, shoot and grain concentrations of Fe were not affected by increasing application of Fe fertilizers. In contrast to soil Fe application, increasing soilapplication of N significantly enhanced Fe concentrations of shoot and grains. There was a close relationship between tissue concentrations of Fe and N. Foliarly-applied Fe fertilizers were either not effective or tended to improve Fe concentrations. However, at a given foliar application of Fe fertilizers, improving N nutrition of plants stimulated grain Fe accumulation. The results indicate an important role of N nutrition in enrichment of wheat grain with Fe. This N effect should be considered in breeding and fertilization programs focusing on enrichment of staple food crops with Fe.