Unraveling soil salinity on potentially toxic element accumulation in coastal Phragmites australis: A novel...

Revealing the key mechanisms influencing the behavior of potentially toxic elements (PTEs) in soil-plant systems is of great significance for environmental protection and grassland development in coastal areas. This study utilized redundancy analysis to assess the effects of soil environmental variables on the concentrations and enrichment of various PTEs in the advantageous forage species Phragmites australis. Advanced models like PLS-PM and RF-SHAP quantitatively assessed soil salinity impacts. The main findings are as follows: (1) P. australis exhibited enrichment capacity for Cd, Cr, and Cu. (2) Soil pH, exchangeable potassium (aK), and exchangeable calcium (aCa) were key determinants of PTE distribution, with Cu being highly sensitive to these variables. (3) Significant interactions between soil electronic conductivity (EC) and pH, as well as between soil EC and aCa (p < 0.01). (4) A pH value of 8.30 and an aCa concentration of 4.4 g/kg were identified as critical thresholds affecting the Cu uptake. These results provide insights into PTE migration and management strategies for coastal grasslands.