In this study, we investigated the effect of different rates of compost (20%, 40%, 60% w/w) in combination with biochar (0%, 2%, 6% w/w) on soil physiochemical properties and the mobility of arsenic (As) and lead (Pb), in addition to the ability of Arabidopsis thaliana (ecotype Columbia-0) to grow and accumulate metal(loid)s. All modalities improved pH and electrical conductivity, stabilized Pb and mobilized As, but only the mixture of 20% compost and 6% biochar improved plant growth. Plants in all modalities showed a significant reduction in root and shoot Pb concentrations compared to the non-amended technosol. In contrast, As shoot concentration was significantly lower for plants in all modalities (except with 20% compost only) compared to non-amended technosol. For root As, plants in all modalities showed a significant reduction except for the mixture of 20% compost and 6% biochar. Overall, our results indicate that the mixture of 20% compost with 6% biochar emerged as the optimum combination for improving plant growth and As uptake, making it the possible optimum combination for enhancing the efficiency of land reclamation strategies. These findings provide a foundation for further research on the long-term effects and potential applications of the compost-biochar combination in improving soil quality.

A combination of compost and biochar has been proven to be a promising strategy to immobilize metal(loid)s and improve soil properties. To the best of our knowledge, no study has been conducted to investigate the effect of biochar and compost combination administered at different rates on mining technosol. Thus, we investigated the effect of different rates of compost (20%, 40%, 60% w/w) in combination with biochar (0%, 2%, 6% w/w) on soil physiochemical properties and the mobility of arsenic (As) and lead (Pb), the ability of Arabidopsis thaliana (ecotype Columbia-0) to grow and accumulate metal(loid)s. All modalities improved pH and electrical conductivity, stabilized Pb and mobilized As, but only the mixture of 20% compost and 6% biochar improved plant growth. Plants in all modalities showed a significant reduction in root and shoot Pb concentrations compared to the non-amended technosol. Whereas, As shoot concentration was significantly lower for plants in all modalities (except with 20% compost only) compared to non-amended technosol. For root As, plants in all modalities showed no significant reduction except for the mixture of 20% compost and biochar. Overall, the mixture of 20% compost with 6% biochar represents the optimum combination for improving plant growth and As uptake.

To gain insight into two different plant strategies (hyperaccumulation and phytostabilization) for managing heavy metals, we conducted a network based functional enrichment analysis. Protein-protein interactions of A. halleri root and shoot were derived by weighted gene co-expression analysis. While, in the case of A. thaliana, protein-protein interactions characterizing the organs were derived from STRING database based on genes known to be expressed in root and shoot. Protein-protein interaction clusters of root and shoot networks of both species were analyzed to identify enriched pathways. Thus, we provide a first clear analysis of the biological peculiarities of different organs of both species.