Effects of soil amendment and foliar selenium applications on cadmium immobilization in soil and accumulation in wheat

Abstract

Wheat cadmium (Cd) contamination is one of the environmental and agricultural concerns worldwide. Here, the effects of applications of foliar selenium (Se) and soil amendments (lime, mixture of biofuel ash and sodium sulfide (DSO), and mixture of iron mine tailing and alkali lignin (MX)) on soil Cd fractions and wheat Cd accumulation were studied using laboratory incubation, greenhouse pot, and field plot experiments. In the laboratory incubation experiment, lime and MX applications significantly increased soil pH, DSO application significantly decreased soil pH, while all the three amendments significantly reduced soil bioavailable Cd fractions by 16%–21% compared to the control without any amendment. Foliar Se application significantly increased the growth and yield of the high-Cd-accumulating cultivar (Puxing5). In the greenhouse experiment, lime and MX applications considerably decreased grain Cd concentration by 55% and 47%, respectively, for Puxing5 and by 24% and 26%, respectively, for the low-Cd-accumulating cultivar (Zhoumai30). In the field experiment, grain Cd concentration was significantly reduced by 68% and 72% by lime and MX applications, respectively, for Puxing5. Application of DSO also significantly reduced grain Cd concentration by 58% for Puxing5 and 25% for Zhoumai30 in the greenhouse experiment, but increased grain Cd concentration by 22% for Puxing5 in the field experiment. Our results implicate that laboratory incubation and greenhouse experiment results are necessary to be verified in field, and foliar Se application is recommended when considering both financial costs and production safety.