Biochar Application Alleviated Rice Salt Stress via Modifying Soil Properties and Regulating Soil Bacterial Abundance and Community Structure

Abstract

Increased soil salinity significantly inhibits crop production worldwide, and biochar may alleviate salt stress. In the present study, the application of biochar significantly increased the biomass of rice under salt stress treatment. The analysis of soil properties demonstrated that biochar application significantly decreased electrical conductivity and soluble Na+ and Cl− contents in the soil under salt stress. In addition, biochar application increased the soil cation exchange capacity, soil organic matter, humic acid, total nitrogen, and total phosphorus contents in the soil, suggesting that biochar improved the soil nutrient conditions. The application of biochar further increased the abundance of soil bacteria and changed the bacterial community structure under salt stress. Proteobacteria, Chloroflexi, and Acidobacteria were the top three phyla in bacterial abundance. Biochar increased Proteobacteria abundance and decreased Chloroflexi abundance, which were considered to be eutrophic bacteria and oligotrophic bacteria, respectively. Redundancy analysis showed that soil bacterial communities were mainly affected by soil pH and EC (p < 0.05). In conclusion, the application of biochar alleviated salt stress in rice via modifying soil properties and regulating the bacterial abundance and community structure.