A soil spiking experiment at two Cd levels (0.72 and 5.20 mg kg-1) was conducted to investigate the effects of rapeseed cake (RSC) at application rates of 0%, 0.75%, 1.5%, and 3.0% (w/w) on iron plaque formation and Cd uptake by rice (Oryza sativa L.) seedlings. The use of RSC did result in a sharp decrease in soil bioavailability of Cd and a significant increase in rice growth, soil pH and organic matter. Application of RSC increased the amount of iron plaque formation and this effectively inhibited the uptake and translocation of Cd into the rice seedlings. RSC was an effective organic additive for increasing rice growth and reducing Cd uptake by rice plant, simultaneously. These results could be used as a reference for the safety use of Cd polluted paddy soil.
Keywords: Cadmium; Iron plaque; Rapeseed cake; Rice (Oryza sativa L.).