Abstract. Biochar has been widely used for the in-situ remediation in the cadmium (Cd) contaminated soil, while the high-cost of biochar limited its application in farmland. In this study, we firstly investigated the possibility of cooperative application of oyster shell and biochar to enhance Cd immobilization efficiency and reduce the cost in field experiments under rice-oilseed rape rotation. Treatments were comprised of: rice planting without amendments (R-PA0); followed with 15000 kg/ha biochar (R-PA1); followed with 15000 kg/ha oyster shell (R-PA2); followed with 7500 kg/ha biochar and 7500 kg/ha oyster shell (R-PA3); rice-oilseed rape rotation without amendments (RT-PA0); rotation with 15000 kg/ha biochar (RT-PA1); rotation with 15000 kg/ha oyster shell (RT-PA2); rotation with 7500 kg/ha biochar and 7500 kg/ha oyster shell (RT-PA3). Results revealed that HOAc-extractable Cd was significantly decreased by 38.46 % in R-PA2. Cd contents in brown rice and oilseed were reduced by 29.67 % in R-PA3 and 19.74 % in RT-PA3 compared with control. Meanwhile, Hazard Quotient of brown rice and oilseed significantly decreased in RT-PA3. The Olsen-P in R-PA3 and RT-PA3 was markedly increased by 187.46 % and 184.73 %, respectively. In addition, activities of urease, catalase, and β-galactosidase in RT-PA3 were significantly increased by 268.88 %, 30.44 % and 245.28 %, respectively. Furthermore, the jiont application of biochar with oyster shell significantly decreased the cost of soil remediation at least 9600 RMB/ha. These results demonstrated that the joint utilization of biochar with oyster shell might be an economical and effective pathway to achieve in-situ remediation of Cd contaminated farmland.

中文翻译：

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牡蛎壳与生物炭的协同应用有效促进集约化工业周边镉污染土壤的原位修复

摘要。生物炭已广泛用于镉（Cd）污染土壤的原位修复，而生物炭的高成本限制了其在农田中的应用。在这项研究中，我们首先研究了牡蛎壳和生物炭协同应用以提高水稻-油菜轮作田间试验中 Cd 固定效率和降低成本的可能性。处理包括： 未经改良的水稻种植（R-PA0）；其次是 15000 公斤/公顷 biochar (R-PA1); 其次是15000公斤/公顷牡蛎壳（R-PA2）；其次是 7500 公斤/公顷生物炭和 7500 公斤/公顷牡蛎壳 (R-PA3)；未经修正的水稻-油菜轮作（RT-PA0）；轮作 15000 公斤/公顷 biochar (RT-PA1); 以 15000 公斤/公顷牡蛎壳 (RT-PA2) 轮作；使用 7500 公斤/公顷生物炭和 7500 公斤/公顷牡蛎壳 (RT-PA3) 轮作。结果表明，在 R-PA2 中，HOAc 可提取的 Cd 显着降低了 38.46 %。与对照相比，R-PA3 和 RT-PA3 糙米和油籽中的 Cd 含量降低了 29.67 % 和 19.74 %。同时，RT-PA3中糙米和油料的危害系数显着降低。R-PA3 和 RT-PA3 中的 Olsen-P 分别显着增加了 187.46 % 和 184.73 %。此外，RT-PA3中脲酶、过氧化氢酶和β-半乳糖苷酶的活性分别显着提高了268.88%、30.44%和245.28%。此外，生物炭与牡蛎壳的联合应用显着降低了土壤修复成本至少9600元/公顷。