Effect of cadmium and arsenic contamination on element content and effectiveness in rhizosphere soils of different forages

To explore the effects of Cd and As composite contaminated soils on the element contents and effectiveness in rhizosphere soils of different forages, the root morphology, rhizosphere soil elements and their availability of 21 forages were studied and analyzed. The results showed: The 21 cultivars showed significant differences in root morphological characteristics. Root length is an index of root morphology that has the highest correlation with other elements and availability. And the correlation between the availability of each element and root morphology was higher than that of element content. Among them, Fe availability was significantly correlated with root morphological characteristics (P <0.05). The contents of different elements and availability varied greatly among the different cultivars. Among the six rhizosphere soil elements, the difference of toxic metal Cd was the largest, while the difference of Al availability was the largest. According to the correlation analysis between the elements and availability of each cultivar, the interaction of the availability of each element is higher than that of the soil element under the composite contaminated of Cd and As. Toxic metals Cd and As affected each other, and there was a very significant positive correlation between the content and availability. Fe, Mn and P had higher correlation with Cd and As.