Fate of selenium in biofortification of wheat on calcareous soil: an isotopic study

Ahmad, Saeed; Bailey, Elizabeth H; Arshad, Muhammad; Ahmed, Sher; Watts, Michael J; Young, Scott D

Abstract

Selenium (Se) biofortification of staple cereal crops can improve the Se nutritional status of populations. A field trial employing an enriched stable isotope of Se (77Se) was undertaken over three consecutive cropping seasons in a coarse textured, calcareous soil in Gilgit-Baltistan, Pakistan. The objectives were to (i) assess the feasibility and efficiency of Se biofortification, (ii) determine the fate of residual Se, and (iii) assess the consequences for dietary Se intake. Isotopically enriched 77Se (77SeFert) was applied, either as selenate or selenite, at three levels (0, 10 and 20 g ha-1) to a wheat crop. Residual 77SeFert availability was assessed in subsequent crops of maize and wheat without further 77SeFert addition. Loss of 77SeFert was c.35% by the first (wheat) harvest, for both selenium species, attributable to the practice of flood irrigation and low adsorption capacity of the soil. No 77SeFert was detectable in subsequent maize or wheat crops. The remaining 77SeFert in soil was almost entirely organically bound and diminished with time following a reversible (pseudo) first order trend. Thus, repeat applications of Se would be required to adequately biofortify grain each year. In contrast to native soil Se, there was no transfer of 77SeFert to a recalcitrant form. Grain from control plots would provide only 0.5 µg person-1 day-1 of Se. By contrast a single application of 20 g ha-1 SeVI could provide c. 47 µg person-1 day-1 Se in wheat, sufficient to avoid deficiency when combined with dietary Se intake from other sources (c. 25 µg day-1).

Citation

Ahmad, S., Bailey, E. H., Arshad, M., Ahmed, S., Watts, M. J., & Young, S. D. (2021). Fate of selenium in biofortification of wheat on calcareous soil: an isotopic study. Environmental Geochemistry and Health, 43(9), 3643-3657. https://doi.org/10.1007/s10653-021-00841-1

• Journal Article Type: Article
• Acceptance Date: Jan 26, 2021
• Online Publication Date: Feb 25, 2021
• Publication Date: 2021-09
• Deposit Date: Feb 12, 2021
• Publicly Available Date: Feb 26, 2022
• Journal: Environmental Geochemistry and Health
• Print ISSN: 0269-4042
• Electronic ISSN: 1573-2983
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 43
• Issue: 9
• Pages: 3643-3657
• DOI: https://doi.org/10.1007/s10653-021-00841-1
• Keywords: Environmental Engineering; Geochemistry and Petrology; General Environmental Science; Water Science and Technology; Environmental Chemistry; General Medicine
• Public URL: https://nottingham-repository.worktribe.com/output/5319322
• Publisher URL: https://link.springer.com/article/10.1007/s10653-021-00841-1