Grass and maize vegetation systems restore saline-sodic soils in the Songnen Plain of northeast China

Establishment of an appropriate vegetation system for reclamation of saline-sodic soils requires studies for specific salt-affected region(s). The phytoremediation of saline-sodic soils has not been well documented in the Songnen Plain of northeast China. Thus, in this study, we aimed to investigate the effects of grass (G) and maize (Zea mays L.; M) vegetation systems, which were established for 5years, on soil properties of 10 typical saline-sodic sampling sites across the Songnen Plain, in comparison with respective nonvegetated areas that were used as controls (CK) for the evaluation of variability among the sampling sites. Physicochemical properties, such as soil moisture, bulk density, porosity, saturated hydraulic conductivity, aggregate stability, pH, electric conductivity, total salt, organic C, total N, and C/N ratio, were analyzed. G and M vegetation significantly produced a 108% and 153% improvement in soil quality, respectively. Additionally, metagenomic analysis of the soil bacterial community revealed that vegetation enhanced the ability of the bacteria to survive in saline-sodic soils, relative to the control. The composition of the bacterial community was highly correlated with all of the soil physicochemical properties. G vegetation had better effects than M vegetation in enhancing soil organic C, total N and aggregate stability, whereas M vegetation more favorably adjusted soil pH, physical structure, and bacterial community than G vegetation did. Collectively, these findings demonstrate that M vegetation has a greater impact than G vegetation on repairing saline-sodic soils in the Songnen Plain of northeast China.