[Safe Utilization Effect of Passivator, Foliar Inhibitor, and Their Combined Application on Cadmium-contaminated...

This study sought to explore the effects of passivator, leaf inhibitor, and their combination on cadmium （Cd）-contaminated farmland and to realize the safe utilization of cultivated land. Coconut shell biochar and calcium magnesium phosphate fertilizer were selected as soil passivators and foliar selenium fertilizer was used as a foliar inhibitor. The best combination was selected through a wheat-maize rotation experiment. The results showed that： ① The soil pH, organic matter content, and CEC could be improved to varying degrees by the application of passivators. ② The grain yield of wheat and maize increased to different degrees after the application of the passivator and foliar inhibitor. ③ The BFL treatment （biochar 1 800 kg·hm^-2 +calcium magnesium phosphate 600 kg hm^-2 + foliar inhibitor 3 L·hm^-2） during the maize season had the best effect, which was significantly lower than that in CK by 13.85%. The effect of the BF treatment （biochar 1 800 kg·hm^-2 + calcium magnesium phosphate 600 kg·hm^-2） in wheat season was the best, which was significantly reduced by 11.21% compared with that in CK. ④ The BF treatment （biochar 1 800 kg·hm^-2 + calcium magnesium phosphate 600 kg·hm^-2） had the best effect on reducing Cd content in roots, straws, and grains of maize and wheat, reducing Cd content in roots of wheat and maize by 20.55% and 27.81%, Cd content in straws by 11.39% and 13.70%, and Cd content in grains by 48.97% and 50.44%, respectively. Therefore, considering all the indexes, the combination of passivators and foliar inhibitor, especially biochar combined with calcium magnesium phosphate fertilizer and biochar and calcium magnesium phosphate fertilizer combined with foliar inhibitor, could more effectively reduce the absorption, transport, and enrichment of Cd in maize and wheat and could be popularized and applied in safe use cultivated land.