Planting Suaeda salsa improved the soil properties and bacterial community diversity in a coastal mudflat

Planting halophytes is an effective strategy to improve saline soils and prevent soil degradation. However, the effects of planting halophytes on saline soil biochemical properties and bacterial communities remain largely unexplored. In this study, soils were sampled from a field where Suaeda salsa was planted over a three-year (TY) and one-year (OY) period on a coastal saline mudflat to investigate the effects of S. salsa growth on soil chemical and biological properties. The results showed that OY and TY significantly reduced soil EC by 76.59% to 79.45% (0-10 cm soil layer) and 31.85% to 43.40% (10-20 cm soil layer) in comparison with the control without S. salsa planting (control). For the characteristics of soil enzyme activity, the alkaline phosphatase activity of TY was significantly reduced in the 0-10 cm soil layer (39.76%) and increased in the 10-20 cm layer (13.37%) relative to control. Alkaline phosphatase activity was the predominant factor affecting soil bacterial community composition. Moreover, the relative abundances of Proteobacteria and Chloroflexi were increased in both the OY and TY treatments compared to control, and were positively correlated with soil organic matter and available nitrogen. The complexity of the soil microbial network and the bacterial community diversity and richness were higher in OY and TY than in control. Our findings suggested that planting S. salsa benefited saline soil in coastal land by reducing soil salt stress, preventing salt soil degradation, and increasing soil bacterial community diversity.