[Effect of Combined Application of an and Sulfur Fertilizer on Cadmium and Arsenic Accumulation in Rice].

The aim of this study was to explore the effects of different sulfur fertilizers combined with sulfate-reducing bacteria on the accumulation of cadmium and arsenic in rice and the formation of iron plaque under long-term flooding conditions and to provide a reference for the safe production of rice fields polluted by moderate and mild cadmium and arsenic. We adopted a pot experiment, selecting two sulfur fertilizers, sulfur and calcium sulfate, and Enterobacter M5 with sulfate-reducing ability, and designed six treatments of single application and combined application of different sulfur fertilizers and M5. The results showed that the combined application of calcium sulfate and M5(CM5) had the best effect on reducing available cadmium and arsenic in rice rhizosphere soil. The combined application of sulfur fertilizer or M5 could reduce the content of cadmium and inorganic arsenic in early season rice grains by 8%-51% and 42%-61%, respectively, under flooding conditions. The content of cadmium and inorganic arsenic in late rice grains decreased by 81%-92% and 41%-62%, respectively. The treatment of the combined application of sulfur and M5(SM5) and CM5 had the best effect on reducing cadmium and arsenic content in both early and late season rice grains. SM5 and CM5 could promote the adsorption of cadmium and arsenic by iron plaque, and the extracted cadmium and arsenic content of ACA in both treatments was significantly higher than that of CK. The extracted iron content of ACA in the CM5 treatment was also significantly higher than that of CK, which indicates that the combined application of calcium sulfate and M5 would promote the formation of iron plaque. The results showed that the combined application of sulfur fertilizer and M5 was better than single application in reducing the content of cadmium and arsenic in grains, whereas the combined application of calcium sulfate and M5 was the best and most stable method.