The vertical mobility of heavy metals in the soil profile may affect their bioavailability. In the present study, a field experiment was conducted for 11 years to investigate the vertical mobility of copper (Cu) and nickel (Ni) and the effects on their bioavailability in soil. It was found that the type and concentration of heavy metals are factors that affect mobility. After 11 years, the mobility and movement of Ni were greater than that of Cu from topsoil (0–20 cm) to subsoil (20–60 cm). The vertical mobility of Cu decreased with the increased addition of Cu, while Ni had the highest vertical mobility when its concentration was the highest in soil. The aging processes and vertical movement could lead to decreases in Cu availability (68–78%) and Ni availability (83–89%). For the decrease of Cu availability in soil, the main driving factor was the vertical movement at low added concentrations, but gradually became aging processes with the increase of added Cu concentrations, while Ni had the opposite tendency. Compared with Cu, aging and vertical mobility played a more prominent role in decreasing the bioavailability of Ni, the bioavailability of Cu changed less than that of Ni after 11 years. The decreased rate of Cu in wheat grains was about 0.26–1.05% while that of Ni was about 2.48–9.46% per year from 2009 to 2018. Therefore, the influence of the vertical downward movement of heavy metals should not be ignored in the assessment of the risk and bioavailability of heavy metals in soil.

重金属在土壤剖面中的垂直迁移可能会影响其生物利用度。在本研究中，进行了11年的野外实验，以研究铜（Cu）和镍（Ni）的垂直迁移率及其对土壤中生物利用度的影响。发现重金属的类型和浓度是影响迁移率的因素。11年后，Ni从表土（0–20 cm）到下层土壤（20–60 cm）的迁移率和迁移率大于Cu。Cu的垂直迁移率随Cu添加量的增加而降低，而Ni在土壤中的浓度最高时垂直迁移率最高。时效过程和垂直运动可能导致铜利用率（68-78％）和镍利用率（83-89％）下降。为了减少土壤中铜的利用率，主要驱动因素是在低添加浓度下的垂直运动，但随着添加铜浓度的增加逐渐成为时效过程，而镍则呈现相反的趋势。与铜相比，时效和垂直迁移率在降低镍的生物利用度方面发挥了更为突出的作用，11年后，铜的生物利用度的变化小于镍的生物利用度。从2009年到2018年，小麦籽粒中Cu的降低速率约为0.26-1.05％，而Ni的降低速率约为每年2.48-9.46％。因此，评估中不应忽略重金属垂直向下运动的影响土壤中重金属的风险和生物利用度。与铜相比，时效和垂直迁移率在降低镍的生物利用度方面发挥了更为突出的作用，11年后，铜的生物利用度的变化小于镍的生物利用度。从2009年到2018年，小麦籽粒中Cu的降低速率约为0.26-1.05％，而Ni的降低速率约为每年2.48-9.46％。因此，评估中不应忽略重金属垂直向下运动的影响土壤中重金属的风险和生物利用度。与铜相比，时效和垂直迁移率在降低镍的生物利用度方面发挥了更为突出的作用，11年后，铜的生物利用度的变化小于镍的生物利用度。从2009年到2018年，小麦籽粒中Cu的降低速率约为0.26-1.05％，而Ni的降低速率约为每年2.48-9.46％。因此，在评估中不应忽略重金属垂直向下运动的影响土壤中重金属的风险和生物利用度。