Abstract:Reducing the accumulation of cadmium in the rice grain is the important target of heavy metal pollution control in China. In this study, a field experiment was conducted in a moderate heavy metal contaminated farmland to study the combined effects of applying amendments and water management on reduction of cadmium uptake of rice plant from soil. The field experiment included eight treatments, i.e., no amendment + shallow irrigation (control), biochar + shallow irrigation, calcium magnesium phosphate-palygorskite-sulfur powder (100:50:1) + shallow irrigation, limestone-zeolite-sulfur powder (100:50:1) + shallow irrigation, no amendment + deep irrigation, biochar + deep irrigation, calcium magnesium phosphate-palygorskite-sulfur powder + deep irrigation, and limestone-zeolite-sulfur powder + deep irrigation. Total dosage of all various amendments was 3 t/hm2. The results showed that the uptake of cadmium by rice plant from soil was reduced significantly by the application of amendments and deep irrigation. Combined effects of both amendments and deep irrigation were greater than those of amendments or deep irrigation. Compared with the control, the contents of cadmium in the grain for treatments of calcium magnesium phosphate-palygorskite-sulfur powder + deep irrigation and limestone-zeolite-sulfur powder + deep irrigation were reduced by 56.53% and 55.53%, respectively. Effect of biochar on reducing the uptake of cadmium was relatively small. The application of the compound amendments could convert the exchangeable cadmium in the soil into relative stable form of cadmium such as carbonate bound, oxide bound and residual forms, and thus reduce the bioavailability of cadmium in soil and the uptake of cadmium from soil. Deep irrigation could enhance the soil reduction and the formation of cadmium sulfide, and achieved the purpose of reducing the uptake of cadmium from soil by dilution effect. The result suggested that application of amendments combined with deep irrigation was a convenient and effective technique to control cadmium uptake of rice plant from soil.