Growth and Cu/Zn uptake in pastures affected by application of vermicompost enriched with high Cu/Zn content

Pot experiment, in which vermicompost enriched with high Cu and Zn contents was applied in aqualf soil to simulate soil metal accumulation from vermicompost application, was conducted to study the effect of vermicompost application on growth of Sorghum Hybrid Sudangrass and Euchlaena Mexicana Schrad as well as their Cu or Zn uptake and soil characteristics. The results showed that shoot growth was improved for the two pastures, while it was significantly inhibited for the root growth of Euchlaena Mexicana Schrad with increasing heavy metal pollution from vermicompost application. Both Cu or Zn contents in shoot or root of Sorghum Hybrid Sudangrass and that in Euchlaena Mexicana Schrad increased after vermicompost application, especially, Cu content in roots of Sorghum Hybrid Sudangrass increased significantly with increasing heavy metal pollution from vermicompost. application In addition, Correlation analysis showed that Cu or Zn contents in two pastures were positively related to acid-extractable and reducible Cu or Zn fraction. So, continuously consecutive application of vermicompost enriched with high Cu and Zn content could contribute to the accumulation of exchanged and reducible Cu or Zn content in soil and pose a potential threat to the plant system.