Effect of Sulfhydryl Attapulgite on Rice Physiology, Soil Properties and Cadmium Forms

[Objective] Cadmium in the soil is easily absorbed by rice and enters the human body through the food chain, so it is of great practical significance to study soil remediation with Cd contaminated. [Method] In this study, the effects of sulfhydryl attapulgite (ATP-SH) on rice physiology, soil properties and Cd speciations were explored by potted rice experiments. [Result] Results showed that ATP-SH significantly increased the net photosynthetic rate and stomatal conductance of rice leaves at full heading stage, with maximum growth rates of 407.00% and 76.43%, respectively. The maximum photochemical efficiency, actual quantum yield and photochemical quenching coefficient of rice leaves increased slightly, while the non-photochemical quenching coefficient increased by 105.15%. The Cd content of rice plants decreased significantly with the increase of ATP-SH addition, and the maximum increase rates of rice and straw were 90.24% and 78.46%, respectively. The ATP-SH had no significant effect on available potassium, available phosphorus, alkali-hydro nitrogen, cation exchange capacity, organic matter and pH value of soils. Compared with the control, the maximum decrease rate of soil available Cd was 82.52%; the maximum reduction rates of ion-exchange Cd, carbonate-bound Cd and weakly organic matter-bound Cd were 92.40%, 60.84% and 51.22%, respectively; the maximum growth rates of iron manganese oxide bound Cd and strongly organic bound Cd were 71.70% and 65.08%, respectively. [Conclusion] The ATP-SH had good passivation effectiveness on Cd in soil.