Combined effect of elemental sulfur application and co-cropping of Alliaria petiolata and Salix aquatica grandis on trace element phytoextraction from contaminated soil

Abstract

To improve trace element (TE) phytoextraction techniques, the use of soil amendments and the co-cropping of accumulator species have been often studied. This study aimed to evaluate the possibility of combining the application of elemental sulfur (S₈) with the co-cropping of two TE accumulating species, Alliaria petiolata and Salix aquatica grandis. A pot experiment was conducted with two soils, lightly (LC) and heavily contaminated (HC) by TE, originated from an industrial wasteland. The application of S₈ significantly reduced pH by 1.17 and 1.23 unit after 64 days in LC and HC soils, respectively, and increased Cd, Cr, Mn, Ni, Pb and Zn contents in soil extractable fraction and plants. An increase in the TE-extraction potential was observed and was greater in LC soil, as the S₈ application led to a reduction of biomass produced by both plants in HC soil. However, co-cropping treatment on HC soil maximized the extraction of TE, especially for Cr and Ni when S₈ treatment was applied, since the plants showed no competition but rather differences in the elements accumulated. Consequently, the combination of S₈ and the co-cropping of A. petiolata and S. aquatica grandis was shown to be relevant for the phytoextraction of TE in HC soils.