Intercropping Sedum Alfredii and Cicer Arietinum L. Does Not Present a Suitable Land Use Pattern For Multi-Metal-Polluted Soil
Abstract Background and aims Intercropping of hyperaccumulators with commercial crops is widely accepted in single-metal-polluted farmland. However, the ecological risks of non-hyperaccumulated metals in intercropping systems have not been revealed. Methods To evaluate Pb and Cu activation and absorption in an intercropped system of Sedum alfredii and Cicer arietinum L., sequential extraction and dissolved organic matter (DOM) characterization were used to describe the migration of metals in the intercropping system. Results This study found that the concentrations of DOM in the S. alfredii monoculture and intercropping system were significantly higher than those in the C. arietinum L. monoculture, and DOM from the former two cultivation strategies had significantly higher Cd, Pb, and Cu extraction capacity than those from the latter. Compared with the C. arietinum L. monoculture, C. arietinum L. intercropping had significantly lower Cd content owing to the depletion of Cd by S. alfredii. However, Cu and Pb concentrations in the former were significantly higher than those in the latter because S. alfredii mobilized these metals but did not hyperaccumulate them. Conclusion The results indicated that intercropping efficiently decreased the potential risk of Cd, but deteriorated the ecological risk of Pb and Cu. Therefore, intercropping does not present a suitable land-use pattern for multi-metal-polluted soil.
