Abstract:
To clarify the differences in the responses of high and low Cd accumulating rice cultivars to different agronomic measures and their Cd mitigation effects in Cd contaminated paddy fields in mining areas, a field experiment was conducted using Liangliangyou 1988 (a high Cd accumulating cultivar, H) and Zhenliangyou
8612 (a low Cd accumulating cultivar, L) as the experimental materials. Six treatments were established: quicklime (T1), soil conditioner (T2), foliar Cd immobilization agent (T3), functional microbial inoculant (T4), fertilizer combination management (T5), and control (CK). Soil available metal concentrations, Cd accumulation in rice plants, and Cd translocation characteristics were analyzed. The results showed that T1 and T2 significantly increased soil pH in both cultivars, but their overall effects on reducing soil DTPA extractable Cd were limited. Only T2 significantly reduced DTPA Cd concentration by 20% compared with CK in the L cultivar at the tillering stage. At maturity, T2 significantly reduced root Cd concentration in the L cultivar by 44.6%. T4 and T5 reduced grain Cd concentration by 62.4% and 57.4%, respectively, and decreased the Cd translocation factors from roots to grains by 60.0% and 47.2%, respectively. In contrast, some treatments increased Cd accumulation in the H cultivar. Specifically, T3 increased root Cd concentration by 105%, while T5 increased grain Cd concentration by 56.1%. Across different treatments, grain Cd concentrations in the L cultivar were generally significantly lower than those in the H cultivar, indicating clear cultivar differences in the Cd mitigation effects of agronomic measures. Overall, rice genotype is an important factor affecting Cd accumulation in mining area paddy fields and the Cd mitigation effects of agronomic measures. Combining the low Cd accumulating cultivar Zhenliangyou
8612 with a functional microbial inoculant or adopting fertilizer combination management can further reduce grain Cd accumulation, providing a basis for screening low Cd rice cultivars and the precise matching of agronomic measures in Cd contaminated paddy fields in mining areas.