生物炭和鸡粪对镉低积累油菜吸收镉的影响

采用田间试验,研究在污灌菜地上施用生物炭和鸡粪对镉低积累油菜生长和镉吸收的影响,并通过重金属形态分析探讨其作用机理.结果表明,施用添加剂可提高油菜地上部产量,高剂量生物炭和鸡粪复配处理增产效果最佳,最大增产率为174%.施用添加剂可显著降低油菜地上部镉含量,其中,高剂量生物炭和鸡粪复配处理降低效果最佳,最大降低率为72.0%,使所有供试品种地上部镉含量满足食品安全标准要求.施用添加剂可显著降低土壤TCLP提取态镉含量,最大降低率为36.5%.施用生物炭和鸡粪促进土壤镉由活性高的可交换态向活性低的有机结合态或残渣态转化,从而显著降低镉的生物有效性和可迁移性.以上结果表明,种植镉低积累品种同时施用生物炭和鸡粪可以满足油菜在镉污染土壤上安全生产的需要.

Effects of biochar and chicken manure on cadmium uptake in pakchoi cultivars with low cadmium accumulation

A field experiment was conducted to investigate the effects of biochar and chicken manure on the growth and cadmium (Cd) accumulation of low Cd accumulating Brassica chinensis grown in a vegetable farmland contaminated by sewage water irrigation, and the immobilization mechanism was elucidated through fractionation of cadmium in the tested soil. Results showed that addition of these additives increased the shoot yield of tested cultivars of Brassica chinensis. The effect of combined applications of high-dose biochar and chicken manure was the most significant, where the yield increased by 174% as compared with the control. The application of these additives significantly decreased shoot Cd concentration of tested cultivars. The effect of combined application of high-dose biochar and chicken manure was the most significant, where the shoot Cd concentration decreased by 72.0% compared with the control, and the shoot Cd concentration of all tested cultivars were lower than the maximum level permitted by the National Food Safety Standard of China (GB2762-2012). The application of these additives could significantly reduce extractable Cd concentration through toxicity characteristic leaching procedure (TCLP) with a maximal reduction rate of 36.5%. The use of biochar and chicken manure could promote transformation of exchangeable Cd into organic bound or residual fractions, resulting in significant reduction of Cd bioavailability and mobility. These data revealed that a combination of planting low Cd accumulating cultivars and applications of biochar and chicken manure could meet the requirement of safe production of Brassica chinensis in Cd polluted soils.