Effects of adding different types and amounts of biochar to saline alkali soil on its salt ions and microbial community in northwest China

Currently, there are few reports on biochar applications when using different raw materials as well as addition levels to saline-alkali soil in northwest China. In this study, we tested the effects of rice-husk biochar (RB) and bamboo biochar (BB), each applied separately at three addition levels (2.5%, 5%, and 10%) on the pH, electrical conductivity (EC), cation exchange capacity (CEC), salt ions, and microbial communities of soil. Our experiment showed that applying the different levels of RB and BB changed the soil pH, EC, CEC, and soil salt ions. The RB-medium level application was evidently the best choice for improving the health of saline-alkali soil in the Baiyin region. While adding biochar negligibly altered the richness of soil microorganisms it did significantly increase their diversity. Accordingly, adding the appropriate amount and type of biochar to soil is crucial for saline-alkali land restoration in Baiyin, northwest China.