EFFECTS OF PHOSPHORUS AND ZINC FERTILIZER MANAGEMENT ON CADMIUM ACCUMULATION IN FLAXSEED

Field studies were conducted over 3 years on three soil types to evalu ate the interactive effects of phosphate and zinc fertilisers on the c oncentration and accumulation of Cd in flaxseed. Flaxseed tends to acc umulate high concentrations of Cd relative to cereal crops, which may be of concern when the flaxseed is entering the health-food market. Ap plication of P, as monoammonium phosphate, increased Cd concentration and accumulation and decreased Zn concentration in flaxseed; the effec t being greater with banded as compared to broadcast placement. Applic ation of Zn, as zinc sulphate, generally decreased Cd concentration, b ut had little effect on Cd accumulation in flaxseed. Concentration of Cd in flaxseed decreased as seed concentration of Zn increased, across soil types and fertiliser treatments. Therefore, lower Zn concentrati on in the seed, whether due to low soil Zn levels, reduced Zn phytoava ilability caused by P application or dilution of seed Zn due to increa sed dry matter production may be associated with increased Cd concentr ations in flaxseed.