Effects of Amount and Chemical Form of Selenium Amendments on Forage Selenium Concentrations and Species Profiles

Jean A Hall; Gerd Bobe; Shelby J Filley; Gene J Pirelli; Mylen G Bohle; Guojie Wang; T Zane Davis; Gary S Bañuelos

doi:10.1007/s12011-022-03541-8

Effects of Amount and Chemical Form of Selenium Amendments on Forage Selenium Concentrations and Species Profiles

Biol Trace Elem Res. 2023 Oct;201(10):4951-4960. doi: 10.1007/s12011-022-03541-8. Epub 2023 Jan 5.

Authors

Jean A Hall¹, Gerd Bobe^{2

3}, Shelby J Filley², Gene J Pirelli², Mylen G Bohle⁴, Guojie Wang⁵, T Zane Davis⁶, Gary S Bañuelos⁷

Affiliations

¹ Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, 97331, USA. Jean.Hall@oregonstate.edu.
² Department of Animal and Rangeland Sciences, College of Agricultural Sciences, Oregon State University, Corvallis, OR, 97331, USA.
³ Linus Pauling Institute, Oregon State University, Corvallis, OR, 97331-4802, USA.
⁴ Department of Crop and Soil Science, College of Agricultural Sciences, Oregon State University, Corvallis, OR, 97331, USA.
⁵ Department of Plant Science, College of Agricultural Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
⁶ USDA, Agricultural Research Service-Poisonous Plant Research Lab, Logan, UT, 84341, USA.
⁷ USDA, Agricultural Research Service-San Joaquin Valley Agricultural Sciences Center, Parlier, CA, 93648, USA.

PMID: 36600168
DOI: 10.1007/s12011-022-03541-8

Abstract

Selenium (Se) agronomic biofortification of plants is effective for alleviating Se deficiencies in human and livestock populations. Less is known about how higher selenate amendment rates, or how foliar compared with granular selenate amendments affect forage Se concentrations. Therefore, we compared the effects of a higher sodium selenate foliar amendment rate (900 vs. 90 g Se ha^-1), and two selenate amendment methods (liquid foliar sodium selenate vs. granular slow-release Selcote Ultra^® at 0, 45, and 90 g Se ha^-1) on Se concentrations and Se species in forages across Oregon. The 10 × amendment rate (900 g Se ha^-1) resulted in 6.4 × higher forage Se concentrations in the first cut (49.19 vs. 7.61 mg Se kg^-1 plant DM, respectively) compared with the 90 g ha^-1 amendment rate, indicating that forages can tolerate higher selenate amendment rates. Most Se was incorporated as SeMet (75%) in the harvested portion of the forage (37 mg Se kg^-1 forage DM of the first cut) and only a limited amount was stored in the selenate reserve pool in the leaves (~ 5 mg Se kg^-1 forage DM). Higher application rates of selenate amendment increased forage Se concentrations in first and second cuts, but carry over in subsequent years was negligible. Application of foliar selenate vs. granular Selcote Ultra^® amendments, between 0 and 90 g Se ha^-1, both resulted in a linear, dose-dependent increase in forage Se concentration. Amendments differed in their Se incorporation pattern (Se%), in that, first cut forage Se concentrations were higher with foliar selenate amendment and second, third, and residual (following spring) cut forage Se concentrations were higher with granular Selcote Ultra® amendment. Given the linear relationship between forage Se concentrations and whole-blood Se concentrations in livestock consuming Se-biofortified forage, we conclude that targeted grazing or other forage feeding strategies will allow producers to adapt to either selenate-amendment form.

Keywords: Forage fertilization; Grasses; Legumes; Selcote Ultra; Selenium biofortification; Selenium concentration; Selenium species.

MeSH terms

Agriculture
Biofortification / methods
Humans
Selenic Acid
Selenium* / metabolism

Substances

Selenium
Selenic Acid