Abstract:

Field experiments were conducted to study the effect of three safe utilization techniques, namely in situ passivation, leaf surface control and water regulation, on the control of cadmium(Cd)-contaminated paddy fields. Through comprehensive analysis of the effective state content of Cd in soil after treatment and the content of Cd in brown rice, the appropriate local safe utilization techniques were obtained. The results showed that the active content of Cd in soil and the content of Cd in brown rice were decreased after passivating agent treatments, among which humic acid treatment had the best effect. Leaf surface intibitor and water control also had certain effect on the reduction of Cd content in brown rice. The mixed leaf surface fertilizer (Se+Si) of organosilicon and inorganic selenium was better than single leaf surface fertilizer. The flooding during of the whole growth period was better than other water management measures, and the lowest Cd content in brown rice under this measure was 0.27 mg·kg^-1. The results showed that under the background of high Cd in acidic soil, the Cd content in brown rice of the three safe utilization techniques all exceeded the standard of GB 2762-2022 《National Standard for Food Safety-Limits of Contaminants in Food》, but all of them could significantly reduce the Cd content in brown rice. The safe utilization effect showed as in-situ passivation > water regulation > leaf surface resistance control.

Key words: rice, in-situ passivation, leaf surface control, water regulation, Cd contamination, safe utilization, Anji