is a harmful heavy metal that can be rapidly taken up and accumulated through the food chain (Cheremisinoff, 2016;Yu, Han, et al., 2017). The application of industrial wastewater, sewage sludge and mining waste to farmland may increase Cd concentrations in soil, polluting soil in China (Di Pierro et al. 2018;He et al. 2015). A recent national survey conducted by the Ministry of Environmental Protection (MEP) of China showed that about 7% of sampling sites were contaminated with Cd (Deng et al. 2019). The contaminated area of Cd and lead (Pb) has reached 20 million ha, accounting for 20% of the country's total soil area (Xue et al. 2014). In Sichuan Province, this situation is more serious: 21% of sampling sites were contaminated. Cd content in the soil of Sichuan is second only to that of Hunan (0.73 mg kg -1 )