Spatial and seasonal variations of soil salinity following vegetation restoration in coastal saline land in eastern China

Abstract

Ecological restoration by plants on coastal saline lands affects salt accumulation, distribution patterns and related mechanisms. In Chongmind Island, eastern China, we explored the way vegetation restoration affected the profile distributions of soil moisture and salinity in various seasons in naturally salt-affected coastal saline land. In four types of vegetation, five soil cores were acquired in the ∼80cm depth range and the sampling depths of the five cores were respectively 0–10cm, 10–20cm, 20–40cm, 40–60cm, and 60–80cm. Soil moisture firstly decreased and then increased with the depth in woodland and shrubland, while soil moisture consistently increased in grassland and control plots. Salt profiles showed the higher values in surface soil in control plots, whereas the pattern of soil salinity showed the reverse trend under vegetation. The effect of vegetation restoration on the profile distributions of salt is significant. In control plots, soil moisture and salinity showed a clear seasonal trend. Soil moisture values were the highest in spring and the lowest in autumn, when values of soil salinity were the highest in summer and the lowest in winter. Relative to control plots, the seasonal trend of soil moisture and salinity under vegetation appeared to be complex for no clear trend was observed. It can be concluded that plant communities significantly affect the spatial–temporal distribution of soil salinity. The selection of plant species is important in the reclamation of costal saline land.