不同土壤调理剂对 Cd 污染稻田修复效果.

To verify the remediation effects of different soil conditioners on lightly Cd-contaminated paddy fields, field plot experiments were conducted in 2021 and 2022 in Daye City, Hubei Province. The effects of 20 soil conditioners on rice yield, brown rice Cd contents, soil pH, and soil available Cd contents were studied. The results showed that compared with the control group, the rice yield changed from - 9.80% to 20.09%, the Cd reduction rate of brown rice was 8.05% to 79.57%, the soil pH increased by - 0.01 to 1.13 units, and the available Cd contents decreased by 4.79% to 25.00%. There was a significant negative correlation between soil pH value and available Cd content for two consecutive years. Meantime, four representative conditioning agents (organic: P3, P4, inorganic: P11, P12) in 2021 were further selected to explore their effects on the transfer and accumulation of Cd in soil-plant and the transformation of five types of occurrence forms in soil. In 2021, the transport coefficient of Cd from soil to root of rice were significantly decreased by all four treatments, and the effect of inorganic conditioners (P11, P12) were significantly better than that of organic conditioners (P3, P4) . The proportion of exchangeable Cd and carbonate-bound Cd in soil decreased by 5.91–17.77 percentage points and 6.33–8.88 percentage points, respectively, under the treatment of various conditioners (P3, P4, P11, P12) . The proportion of Fe-Mn bound Cd, organically bound Cd and residual Cd in soil were increased by 3.47–16.31, 0.80-6.50 percentage points and 4.82–7.05 percentage points, respectively. Organic conditioners (P3, P4) tend to convert soil Cd to organically bound Cd, while inorganic conditioners (P11, P12) tend to convert soil Cd to Fe-Mn bound Cd. Overall, two years of field experiments showed that the selection of suitable conditioners could realize the safe utilization of Cd-polluted farmland, and P12 conditioner (CaO≥28%) was recommended as the conditioner for the remediation of mild Cd pollution in Daye City, Hubei Province. [ABSTRACT FROM AUTHOR]