An Investigation into the Growth of Lolium perenne L. and Soil Properties Following Soil Amendment with Phosphorus-Saturated Bauxite Residue

Reuse options for bauxite residue include treatment of phosphorus (P)-enriched wastewaters where the P-saturated media offers fertiliser potential. However, few studies have assessed the impact on soil properties. Two types of spent P-saturated bauxite residue were applied to soil and compared to conventional superphosphate fertiliser as well as a control soil. Soil physico-chemical properties, worm Eisenia fetida L. choice tests, and Lolium perenne L. growth and elemental uptake were examined. Comparable biomass and plant content for L. perenne in the P-saturated bauxite residue treatments and those receiving superphosphate, indicated no phytotoxic effects. E. fetida L. showed a significant preference for the control soil (58 %+/- 2.1%) over the amended soils, indicating some form of salt stress. Overall, P-saturated bauxite residue was comparable to the superphosphate fertiliser in terms of the plant performance and soil properties, indicating the potential recycling of P from wastewaters using bauxite residue as a low-cost adsorbent.

Automated summary

This study demonstrates the potential of using bauxite residue as a low-cost adsorbent for phosphorus (P) recycling from wastewaters. Application of bauxite residue does not significantly affect soil properties, and its performance in plant growth and soil properties is comparable to conventional superphosphate fertiliser.