Spatial Variability And Influencing Factors Of Soil Salinization In Longkou Area,Shandong

Longkou city is adjacent to Bohai Sea and Laizhou Bay.The seawater intrusion not only infects the local groundwater,but also deteriorates the groundwater quality.It also causes local soil salinization,which has adverse effects on the soil quality and fertility of the study area.The emergence of problems such as area reduction and deterioration of the ecological environment has had a very serious negative impact on the living standards of local residents and industrial and agricultural production.Therefore,it is particularly important to find out the soil salinization in the study area.In this study,in the spring and summer of 2018,a wide range of field soil samplings,in three layers of 0³0 cm,30⁶0 cm and 60⁹0 cm,were conducted in Longkou city,Shandong Province.Using SPSS software,Pearson correlation analysis was carried out on soil salinity and ions,and principal component classification analysis was carried out to determine the degree and type of soil salinization.Using the combination of geostatistics and GIS technology,the semivariance function model was determined using GS+software.The spatial distribution of soil salinity was plotted by,Arcgis using the established models.The effects of land use and groundwater characteristics on soil salinity and ion space distribution were analyzed.The main conclusions are as followings:?1?There is a significant positive correlation between soil salinity and various ions.The four ions of Na⁺,Mg²⁺,Cl^-and SO₄^2-are the main characteristics of soil salinization in the study area.In spring,the ions exhibit a sub-polymeric character,while in summer they exhibit a hybrid character.?2?The soil pH is neutral,and the overall salinization degree of the study area is mild to moderate.In the spring,all the soil layers of the soil are neutral and moderately saline soils.And in summer,they are all neutral and mild saline soils,and the degree of salinization in spring is slightly higher.In the spring,the sulfate-chloride salt-soiled soil is dominant,while in the summer,the sulfate-chloride salt-soil and the chloride-sulphate-type saline soil are the main types.?3?The soil salinity of different layers in spring and summer showed a strip-like and patchy spatial pattern.With the increase of depth,the degree of salinization decreased.The overall salt content in spring was greater than that in summer.And the spatial distribution showed the eastern part of the study area has higher salinity,followed by the north,and the lower middle and south.The trend is mainly affected by both seawater intrusion and groundwater recharge.?4?In areas with serious soil salinization,the land is mostly salt fields or weedy wasteland,followed by vineyards and apple orchards,and the inland areas are mostly distributed with wheat fields and corn fields.There is a negative correlation between soil salinity and groundwater level,which is closely related to groundwater conductivity and groundwater ion,and has a significant correlation with groundwater salinity.Salinization is serious in areas with serious seawater intrusion.