Usefulness of Foliar Nitrogen-Sulfur Ratio in Spring Red Wheat

ABSTRACT

Sulfur (S) availability indicators are necessary for a rational use of fertilizers. Experiments were carried out to evaluate the sensitivity and stability of nitrogen (N):S ratio in spring red wheat. Yield responses were determined in three replications over five experimental sites. Sulfur application did not increase N concentration in plant, whereas the effect on total S concentration was varied. Results showed 25, 35, 80, and 85% correctly diagnosed samples at stages Z22, Z24, Z31, and Z39, respectively. In treatments without S limitations, a decrease in N:S ratio was observed as the crop cycle advanced. Nitrogen: S ratio differed according to the site; however, these variations tend to decrease as the crop cycle advance. In summary, for spring red wheat, N:S ratio in plant is a useful method for S deficiencies diagnostic from the end of tillering to flag leaf.

Keywords:

• spring red wheat
• sulfur
• diagnosis
• N:S ratio

ACKNOWLEDGMENTS

This work is part of a thesis submitted by Nahuel I. Reussi Calvo in partial fulfillment for the requirements for the degree of Doctor, Universidad Nacional de Mer Del plata (UNMP). This study was made possible with financial support of INTA (Project AERN 5656) and FCA UNMP (15/A213).

Notes

∗Walkley-Black (Nelson and Sommers, 1996).

† Cloruro de Potasio (Keeney and Nelson, 1982).

‡ Bray 1 (Bray and Kurtz, 1945).

§ Ca(H₂PO₄)₂ (Islam and Bhuiyan, 1998).

∗Not determined.