Nitrogen‐Sulfur Relationships in Wheat (<i>Triticum aestivum</i> L.), Corn (<i>Zea mays</i>), and Beans (<i>Phaseolus vulgaris</i>)¹

Abstract

Abstract The nitrogen‐sulfur ratios in the tops and roots of wheat ( Triticum aestivum ), corn ( Zea mays ), and beans ( Phaseolus vulgaris ) were studied in relation to N and S supplies in soil. Greenhouse studies showed that when S became limiting, additional N did not affect either the yield or protein level of the plants, but the nonprotein N (nitrates, amides, and amino acids) increased. There was a close relationship between the amounts of N and S metabolized in the plants. The data indicated that one part sulfur was required for every 12 to 15 parts nitrogen to insure maximum production of both dry matter and protein. As the use of nitrogen fertilizers increases, the possibility that S may become limiting also increases, and adequate consideration of S becomes necessary. This is especially true in greenhouse studies, where S may become limiting very quickly.