Spatial pattern of soil salinity and soil salinization in area around Bohai Sea

The objective of this study was to characterize the spatial distribution of soil salinity variables in the low plain around the Bohai Sea, and to provide some suggestions on utilizing brackish water for agricultural irrigation and mitigating the crisis of water resources. Soil samples were collected from 127 sites in this low plain, each of them was taken from 0 to 60 cm in 5 or 10 cm increment, and soil salinity of each soil sample was analyzed. In addition, shallow groundwater depth in 130 sites and total dissolved solid of groundwater samples in 128 sites were measured. The geostatistical method combined with GIS technique was used to analyze spatial variability and distribution of soil salinity in this low plain. Results showed that the soil salinity in the surface layer was varied greatly, soil salinity in other layers was moderate degree in horizontal direction, while in the vertical direction, their differences were small. Spatial correlated distance was 35.3 km for the surface soil, while its value was increased with the depth increasing, which reached to 59.7 km for 50–60 cm soil layer. Soil salinity content showed an increasing trend from inland plain to the east coastal plain, and similar results were found in different layers. The percentages of no salinity, slight salinity and medium salinity soils for 0 to 5 cm soil layer were almost equal, while heavy salinity soil was little or no saline soil was existed from 5 to 60 cm soil layer. Generally, the main types of soil salinity were no salinity and slight salinity, so it is suitable for irrigation to exploit the shallow brackish water in some extents.