基于烟叶Cd消减率和修复边际效率评价Cd钝化剂修复效果

我国农田镉污染问题日益严重，低成本、高效、绿色环保的土壤镉钝化技术研发是我国目前农田重金属污染治理需要解决的关键问题。以湖南镉（Cd）重度污染水稻土为对象，以云烟87和K326两个烤烟品种为试材，通过盆栽试验，以土壤Cd有效态含量降低率、烟叶Cd消减率和修复边际效率为指标，对4种不同钝化剂的修复效果进行了评价。结果表明，土壤钝化剂的添加显著降低了烟叶对Cd的吸收（p<0.05）。与对照相比，土壤Cd有效态含量降低率为17.69%~35.65%，烟叶Cd消减率为25.08%~60.75%，4种钝化剂修复边际效率为2.84%~21.98%；随着钝化剂施用浓度的增加，土壤Cd有效态含量降低率和烟叶Cd消减率均显著增加，但烟叶Cd修复边际效率呈明显递减趋势，1%施用浓度比2%和4%施用浓度分别高出69.42%和152.73%；钝化剂对K326烟叶的Cd修复边际效率比云烟87高13.21%。综合土壤Cd有效态含量降低率、烟叶Cd消减率和修复边际效率3个评价指标，不同钝化剂的修复效果顺序为生物炭钝化剂FB > 羟基磷钝化剂FP > 岩基钝化剂FA > 黏土矿物钝化剂FS。

Remediation Effect of Cd Amendments Evaluated by Tobacco Leaf Cd Depletion Rate and Remediation Marginal Efficiency

Cadmium (Cd) pollution in cropland is becoming an increasingly serious issue in China. In present, development of low cost, high efficiency, and going green and environmental protection remediation materials are critical in remediation of heavy metal polluted soils. In this study, two tobacco varieties (Yunyan87 and K326) were used, and Cd heavily polluted paddy soil in Hunan province were collected for pot experiment, for the sake of investigating remediation effect of different amendments on Cd heavily polluted soils. Remediation effect was evaluated by soil available Cd reduction rate, tobacco leaf Cd depletion rate (%), and remediation marginal efficiency (RME) (RME, defined as tobacco leaf Cd reduction rate based on 1500 yuan cost per hectare for the tested soils). The results indicated that:the Cd uptaken by tobacco was significantly reduced by the soil amendment applications (p<0.05). Compared with control (CK), soil available Cd reduced from 17.69% to 35.65%, Cd depletion rate of tobacco leaf was 25.08%-60.75%. The RME of four soil amendment ranged from 2.84% to 21.98%. As the soil amendment application concentration increases, the reduction rate of soil available Cd and tobacco leaf Cd increased significantly, while the RME showed a diminishing tendency. The RME of 1% soil amendment application was 69.42% and 152.73% higher than 2% and 4% applications respectively. RME aiming at K326 was 13.21% higher than Yunyan87. By considering soil available Cd reduction rate, tobacco leaf Cd depletion rate (%), and RME, the remediation effect of different amendments ordered as:biochar FB > Hydroxyapatite FP > rock foundation FA > clay mineral FS.