Effects of Phosphorus and Zinc Fertiliser Management on Cadmium Accumulation in Flaxseed

Abstract

Field studies were conducted over 3 years on three soil types to evaluate the interactive effects of phosphate and zinc fertilisers on the concentration and accumulation of Cd in flaxseed. Flaxseed tends to accumulate high concentrations of Cd relative to cereal crops, which may be of concern when the flaxseed is entering the health-food market. Application of P, as monoammonium phosphate, increased Cd concentration and accumulation and decreased Zn concentration in flaxseed; the effect being greater with banded as compared to broadcast placement. Application of Zn, as zinc sulphate, generally decreased Cd concentration, but 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 concentration in the seed, whether due to low soil Zn levels, reduced Zn phytoavailability caused by P application or dilution of seed Zn due to increased dry matter production may be associated with increased Cd concentrations in flaxseed. © 1997 SCI.