A field comparison of pasture selenium uptake from different forms of selenium fertiliser

Abstract

The uptake of selenium (Se) by pasture herbage from four different Se fertiliser materials was determined in a field experiment throughout the course of a whole year. The products tested were: the commercially available Selenium Chip™; Selcote® Ultra; and two new formulations (Ravensdown A and B), manufactured in a way to slow the release of Se in the form of sodium selenate. All four Se fertilisers increased pasture herbage Se concentrations above the level required to meet the nutritional requirements of grazing livestock; however, the size and duration of the responses varied between products. The Ravensdown A product was as effective as Selcote Ultra at maintaining pasture Se concentrations above the critical animal health level for the whole year of the trial. The effects of the other two products, particularly the Selenium Chip, were not so long‐lasting. Recoveries of Se in the pasture herbage throughout the year ranged between c. 15 and 17% of the Se originally applied in the fertilisers.

Key words:

• fertiliser trial
• pasture selenium uptake
• selenium fertilisers
• water‐soluble selenium