Effect of Lithium Slag Application on Saline–Alkali Soil Amelioration and Vegetable Growth

Increased attention has been attracted to saline–alkali soil amelioration due to the growing serious salinization of soils in the world. Lithium slag (LS) is an acid by-product of lithium production with potential properties to ameliorate alkalinity in saline–alkali soils. In this study, LS was reused as a saline–alkali soil amendment and potted plant experiments in a greenhouse were performed to evaluate the effect of LS application on the soil amelioration and the growth of vegetables (roquette and radish) in the saline–alkali soil during the 5-week growth period. LS was added at the amount of 0.5%, 1.0%, 2.0%, 5.0%, 8.0% and 10.0% ( w / w ) levels. Results showed that saline–alkali soil pH dropped obviously with the increase in LS application. Accordingly, the germination, survival and growth of roquette and radish were significantly improved by LS addition, especially at the optimum amount of 0.5% and 1.0% ( w / w ) in the saline–alkali soil. In contrast to the untreated saline–alkali soil, LS addition at 0.5% and 1.0% ( w / w ) levels increased the roquette’s height by 49.7% and 36.1% and increased the radish’s height by 54.6% and 53.7%, respectively. However, the soil electrical conductivity (EC) and soluble salt content increased with the addition of LS, and the salt stress induced by excessive LS (over 5.0% level) could inhibit the growth of plants. This study proposes a new way for the effective application of LS in the amelioration of saline–alkali soil in order to realize environment and resource sustainability.