Effect of selenium fertilizer source and rate on grain yield and selenium and cadmium concentration of durum wheat

Abstract

Field studies were conducted for 3 yr at two locations in Manitoba, Canada, to evaluate the effect of various sources and rates of Se fertilizer on crop growth and the Se and Cd concentrations of durum wheat. Selenium concentration in durum wheat grown without Se application ranged from 195 to 532 µg kg-1 over the 6 site-years. Selenium seed coating, “Selcote” commercial granular fertilizer, and a foliar spray of sodium selenate solution applied at Feekes stage 5 all increased Se concentration in durum wheat grain at all locations, without negative effects on crop stand, biomass yield or grain yield. Regardless of treatment, Cd concentration in the grain was generally below proposed regulatory limits. Application of Se did not reduce Cd concentration in the grain, regardless of Se source. Selenium fertilization can be used to increase Se concentration of durum wheat, but is not an effective means of reducing the grain Cd concentration. Key words: Selcote, sodium selenate, seed-coating, selenium, cadmium