Tolerance and Environmental Effects of Chinese Milk Vetch (Astragalus sinicus L.) Planted in Cu-Contaminated Soil

Phytostabilization has become an efficient in situ remediation technology. In order to investigate the tolerance and environmental effects of Chinese milk vetch (Astragalus sinicus L.) planted in Cu-contaminated soil, pot experiments were conducted. In this experiment, Chinese milk vetch had been planted in soil with gradual Cu concentrations (0, 200, and 400 mg kg−1) for 5 months. The indicators of plants and soil were determined after planting, such as physiological indexes, biomass and bioaccumulation of Chinese milk vetch, total nitrogen and available Cu in soil, and composition of soil microbial community. Chinese milk vetch could maintain a stable physiological state and strong nitrogen fixation ability in Cu-contaminated soil, and activate Cu in soil to absorb it in roots. Meanwhile, the soil microbial community compositions were affected by the planting of Chinese milk vetch. Chinese milk vetch could be planted as a candidate reclamation plant in Cu-contaminated soil due to its Cu tolerance and play a role in phytostabilization of heavy metals while keeping its agricultural value as green manure.