Simultaneous improvement of protein concentration and amino acid balance in maize grains by coordination application of nitrogen and sulfur

The synergistic regulation effect of coordinated application of nitrogen (N) and sulfur (S) on the protein concentration and amino acid balance in maize grains was investigated. The results showed that the coordinated application of N and S significantly increased the protein concentration of maize grains, and there were significant N × S interactions. In addition, the coordinated application of N and S also increased concentration of essential amino acid in maize grains, and N × S interactions reached a significant level. Simultaneously, the ratio of total essential amino acid to total non-essential amino acid in maize grains was increased, which promoted the balance of amino acid in grain protein. Notably, lysine and tryptophan that were usually most deficient in maize grains were significantly increased due to coordinated application of N and S, which was critical for improving nutritional quality of maize. Overall, synergistic application of N and S simultaneously improved protein concentration and amino acid balance in maize grains, thereby significantly improving nutritional quality of maize.