Effect of selenium prills on pasture herbage selenium concentrations

Abstract

Traditionally, selenium drenches or injections have been used to prevent the occurrence of selenium responsive diseases in livestock. However, the use of selenium containing fertilisers to enhance pasture herbage selenium concentrations, and thus prevent selenium deficiency, has also been examined (Allaway et al. 1966; Cary et al. 1967; Grant, 1965). The rapid uptake of fertiliser selenium by herbage and its potentially toxic effects, has lead some workers to conclude that pasture topdressing is not a very suitable method of maintaining the selenium status of grazing livestock (Underwood, 1977; Archer, 1983; Oldfield, 1972). In New Zealand however, since 1982, topdressing pastures with selenate has been permitted using pellets containing not more than 10 g/kg of selenium as sodium selenate, for application at a rate not exceeding 1.0 kg of pellets per hectare (Watkinson, 1983). The present paper reports results from pot and field experiments aimed at evaluating the use of SelcoteR Selenium Prills as a means of enhancing plant selenium levels.