Mercury (Hg) is toxic and can affect human health through soil entering food chain. Spinach absorb easily heavy metals. Corn stover biochar can improve soil structure and physicochemical property. This study wanted to establish a Hg-corn stover biochar-soil-spinach model including 1 control group (without HgCl₂ and corn stover biochar) and 24 treatment groups (with HgCl₂ or/and corn stover biochar). Hg concentration was 0, 1, 2, 4, and 6 mg kg^-1, respectively. Corn stover biochar contents were 0%, 1%, 3%, 5%, and 7% w/w, respectively. The results showed that residual Hg concentrations was the largest and water soluble and exchangeable Hg as well as carbonate bound Hg concentrations were the lowest among five Hg forms. Hg concentrations in four Hg treatment groups were higher than the control group in dose-dependent manner. The deposition of 6 mg kg^-1 Hg was the highest. Corn stover biochar decreased Hg migration from soil to leaching solution and spinach, and passivation effect of 7% concentration of corn stover biochar was the best. Besides, corn stover biochar relieved the increase of methyl Hg caused by Hg in soil. Moreover, Hg concentration in roots was the highest and Hg concentration in stems was the lowest in spinach. Furthermore, Hg absorbed by roots was more than the sum of Hg absorbed by stems and leaves. In addition, we also found that the measured soil Hg concentrations were coincided with the predicted soil Hg concentrations under 1, 2, and 4 mg kg^-1 Hg concentrations, except 2 mg kg^-1 Hg at 7% C. Under 6 mg kg^-1 Hg concentration, measured soil Hg concentrations was lower than that of the predicted soil Hg concentrations. Taken together, our findings indicated that corn stover biochar can increase edible safety of spinach by immobilizing Hg in soil and be used as an organic amendment.

汞（Hg）有毒，可通过进入食物链的土壤影响人类健康。菠菜容易吸收重金属。玉米秸秆生物炭可以改善土壤结构和理化特性。这项研究想要建立一个Hg-玉米秸秆生物炭-土壤-菠菜模型，包括1个对照组（不含HgCl ₂和玉米秸秆生物炭）和24个治疗组（HgCl ₂或/和玉米秸秆生物炭）。汞浓度为0、1、2、4和6 mg kg ^-1， 分别。玉米秸秆生物炭含量分别为0％，1％，3％，5％和7％w / w。结果表明，在五种形式的汞中，残留的汞浓度最大，水溶性和可交换的汞以及与碳酸盐结合的汞浓度最低。四个汞治疗组中的汞浓度以剂量依赖性方式高于对照组。6 mg kg ^-1的沉积汞含量最高。玉米秸秆生物炭减少了汞从土壤到淋溶液和菠菜的迁移，其中浓度为7％的玉米秸秆生物炭的钝化效果最好。此外，玉米秸秆生物炭缓解了土壤中​​汞引起的甲基汞增加。此外，菠菜中根中的Hg浓度最高，茎中的Hg浓度最低。此外，根吸收的汞大于茎和叶吸收的汞之和。此外，我们还发现，所测量的土壤汞浓度下1与预测的土壤汞浓度一致，2，和4个毫克千克^-1汞浓度，除了2毫克千克^-1汞柱在7％下在6毫克公斤^-1汞浓度，测得的土壤汞浓度低于预测的土壤汞浓度。综上所述，我们的发现表明玉米秸秆生物炭可通过将Hg固定在土壤中来提高菠菜的食用安全性，并可用作有机改良剂。