Heavy metal contamination of soils is a serious issue with various consequences in Hunan Province. Here, we aimed to determine the effect and action mechanisms of lychee biochar on the remediation of Pb, Cd, As, and Zn from soil using sunflower (Helianthus annuus). Different amounts of lychee biochar (2.5, 5, and 10%) were added to heavy metal-contaminated soil in the Shuikoushan mining area, Hunan Province. The effects of biochar on the biomass of sunflower plants, and the accumulation and distribution of Pb, Cd, As, and Zn in sunflower plants, and changes in Pb, Cd, As, and Zn concentrations in the rhizosphere soil were studied. The application of biochar stimulated the growth of the sunflower plants, with the maximum biomass recorded in the 5% biochar treatment; however, above this level, biochar inhibited plant growth. Pb, Cd, As, and Zn in sunflower plants were redistributed with biochar addition. The concentration of Pb, Cd, As, and Zn in the leaves and receptacles of sunflower plants increased with biochar application, but their concentration in the roots, stems, and seeds significantly decreased compared with the control. The total amount of accumulated Pb, Cd, and As in sunflower plants increased by 22.9–58.9%, 15.8–42.3%, and 67.9–110%, respectively, compared with that in the control. In the biochar treatments, the total amount of accumulated Zn in sunflowers decreased by 13.8–37.2%, compared with that in the control. The accumulated Pb, Cd, and As in sunflower plants have an antagonistic effect on Zn required by sunflowers. The sunflower plants significantly reduced the concentration of Pb, Cd, As, and Zn in contaminated soil (P < 0.05), which decreased by 12.4, 11.0, 4.35, and 8.17%, respectively, compared with that before planting sunflower. The addition of biochar in heavy metal-contaminated soil significantly enhanced the heavy metal-remediation effect of sunflower. Compared with the control (0% biochar), 10% biochar application decreased the Pb, Cd, As, and Zn concentrations in the rhizosphere of sunflower plants, by 40.6, 31.6, 35.4, and 30.8%, respectively. In conclusion, lychee biochar enhanced the remediation of heavy metals in contaminated soil.

土壤重金属污染是一个严重的问题，在湖南省造成各种后果。在这里，我们旨在确定荔枝生物炭对向日葵（向日葵）从土壤中修复铅，镉，砷和锌的作用和作用机理。）。向湖南省水口山矿区的重金属污染土壤中添加了不同数量的荔枝生物炭（2.5％，5％和10％）。研究了生物炭对向日葵植物生物量的影响，以及向日葵植物中铅，镉，砷和锌的积累与分布以及根际土壤中铅，镉，砷和锌的浓度变化。生物炭的施用刺激了向日葵植物的生长，在5％生物炭处理中记录了最大的生物量。然而，高于此水平，生物炭抑制了植物的生长。随着生物炭的添加，向日葵植物中的Pb，Cd，As和Zn被重新分配。随着生物炭的施用，向日葵植物的叶片和容器中的Pb，Cd，As和Zn的浓度增加，但它们在根，茎，与种子相比，种子明显减少。与对照相比，向日葵植物中铅，镉和砷的累积总量分别增加了22.9–58.9％，15.8–42.3％和67.9–110％。与对照相比，在生物炭处理中，向日葵中锌的累积总量减少了13.8–37.2％。向日葵植物中积累的Pb，Cd和As对向日葵所需的Zn具有拮抗作用。向日葵植物显着降低了受污染土壤中Pb，Cd，As和Zn的浓度（与对照相比，向日葵中锌的累积总量减少了13.8–37.2％。向日葵植物中积累的Pb，Cd和As对向日葵所需的Zn具有拮抗作用。向日葵植物显着降低了受污染土壤中Pb，Cd，As和Zn的浓度（与对照相比，向日葵中锌的累积总量减少了13.8–37.2％。向日葵植物中积累的Pb，Cd和As对向日葵所需的Zn具有拮抗作用。向日葵植物显着降低了受污染土壤中Pb，Cd，As和Zn的浓度（P <0.05），与种植向日葵前相比分别下降了12.4、11.0、4.35和8.17％。在重金属污染的土壤中添加生物炭可显着增强向日葵的重金属修复效果。与对照（0％生物炭）相比，施用10％生物炭可使向日葵植物根际的Pb，Cd，As和Zn浓度分别降低40.6％，31.6％，35.4％和30.8％。总之，荔枝生物炭增强了土壤中重金属的修复。