Microorganisms facilitated the saline‐alkali soil remediation by biochar: Soil properties, microbial communities, and plant responses

Abstract Saline‐alkali soil degradation is a significant environmental problem with a negative impact on sustainable agroforestry development. Therefore, efficient remediation methods are urgently required. A potential solution to this problem is using biochar produced from bamboo waste and inoculated with plant growth‐promoting microbes as cleaner production materials for saline‐alkali soil. The present study investigated the potential of combining biochar, microbes, and dwarf bamboo to improve saline‐alkali soil. Different application rates (1%, 3%, and 5% of soil mass) of biochar were added to coastal saline soil planted with dwarf bamboo ( Pleioblastus argenteastriatus ) in pot experiments. Soil physicochemical properties, microbial communities, and plant responses were systematically studied. Bamboo and microbial‐modified biochar effectively decreased soil pH and electrical conductivity and increased soil nutrient contents. Compared with untreated soil, the relative abundance of the dominant bacterial phyla Acidobacteria, Actinobacteria, and Chloroflexi, and dominant fungal phyla Basidiomycota increased after applying biochar and modified biochar. With the increase in application concentration, the antioxidant activities of modified biochar decreased, biochar peroxidase and catalase content decreased, and the malondialdehyde content of bamboo biochar and microbial‐modified bamboo biochar decreased. The biomass of bamboo with added biochar and modified biochar was significantly higher than that of untreated soil. Comprehensive correlation and redundancy analyses showed that the bacterial and fungal communities were greatly affected by soil factors, especially soil pH, electrical conductivity, total organic carbon, potassium, and sodium ions. The findings of this study suggest that 5% bamboo biochar and 3% modified biochar benefit soil remediation, improve the stress resistance of dwarf bamboo, and enhance plant growth. Therefore, combined biochar–microbe remediation has great potential for the sustainable improvement of saline‐alkali soil.