CONTENT of Cdin freshvegetablescan be decreased by application of silicate fertilizerswhich decrease Cd concentration in the plant tissues. Lettuce plants (Lactuca sativa L.) were evaluated in a pot experiment were grown on artificially contaminated soil with Cd at 0, 5, 10 and 15 mg Cd kg^-1 applied as cadmium sulfate hydrate (3 CdSO₄: 8 H₂O).Three levels of Si (0, 100 and 150 mg Si kg^-1) were applied as calcium silicate (CaSiO₃) to assess Cd status in soil and plant. Si increased plant dry weight and the highest dry weight was given by the treatment of 5mg Cdkg^-1 and150 mg Si kg^-1. Si-treated soil showed greater Cd than untreated one. All Cd-treated soils had considerably high contents of DTPA-extractable Cd in soils. Relationships between Cd and Si treated soils and Cd concentration in plant roots show that increased Si and Cd application leads to decreasing the Cd in the root after harvesting. The bio-concentration factor (BCF) was calculated to assess Si influences on Cd uptake. The BCF is a ratio of metal content in plant roots to its content in soil, in most cases the BCF1 and decreased gradually with the Si additions.
 
The treatment of 150 mg Si kg^-1 proved an effective level of Si that decreased Cd uptake in lettuce plant.