Microbial Diversity and Physicochemical Properties of Rhizosphere Microenvironment in Saline-alkali Soils of the Yellow River Delta

Abstract

Soil salinity and alkalinity are major problems that limit agricultural development across the world. The planting of halophytes and salt-tolerant plants could improve saline-alkaline soil character, while the microorganisms in saline-alkali soils play an important role in the growth of halophytes and salt-tolerant plants. In this study, four representative plants of maize, cotton, Phragmites australis (Cav.) Trin. ex Steud, and Suaeda salsa were selected in saline-alkali soil. Soil samples were collected to explore the relationship between the main bacterial communities of roots and non-roots and the physical and chemical properties and soil microbial diversity of saline-alkali soil. The results showed that the root microorganisms of Suaeda salsa affect the pH of the soil to some extent, and the soil salinity is negatively correlated with the soil nutrient content. The top five bacterial gates with higher relative abundance in all soil samples were α-Proteobacteria, Actinobacteria, Bacteroides, Chloroflexi, and Acidobacteria. Cotton, Phragmites australis(Cav.) Trin. ex Steud, and Suaeda salsa have large differences in salt-tolerant bacteria between root soils and non-root soils. High-throughput sequencing results show that salt tolerance is different between the three plant roots and non-root soils. Bacterial genus, such as Actinophytocola and Lechevalieria, differ greatly in cotton soil, Bacillus and Filobacillus differ greatly in Phragmites australis (Cav.) Trin. ex Steud. soil, and Echinicola differ greatly in the soil of Suaeda salsa. This research can provide a theoretical basis for promoting plant growth in saline-alkali soil.