With regard to the interaction effects between the soil water and salt parameters, the C S was in negatively correlated with the RWC at the highly significant ( P < 0.01) and significant levels ( P < 0.05) in the top and shallow soil layers, respectively, whereas a highly significant positive correlation ( P < 0.01) was observed in the deep soil layer.
Responses of absolute concentration of soil solution to different groundwater level ( Fig 4A–4E ) shows that with increases in the G L , the C S followed an initial increasing and then decreasing trend in different soil layers, although the top soil layer mainly exhibited an increasing trend.
When the G L is relatively increased, the soil salt rapidly accumulates in the surface layer to form a crust-like protective layer that reduces evaporation and results in a decreasing trend in the S C .