Spatio-temporal variability of soil salinity in the Yellow River Delta using electromagnetic induction

Aiming at the spatial complexity and genesic repeatability of soil salinization in Lower Yellow River Delta, with the application of electromagnetic induction EM38 and its mobile sensing system, spatio-temporal variation of soil salinity in typical field of this region during two critical seasons was analyzed by using GIS and geostatistics method. Results indicate that apparent soil electrical conductivity is significantly correlated with salinity. Soil salinity at two periods both exhibits compound scale effect of multilayer spatial structures, and short-range variation is the chief constitute of spatial heterogeneity. Difference of land use patterns results in weak anisotropy of soil salinity at autumn period, and topography leads to fluctuation of anisotropic ratio in the whole lag size at spring period, while it remains isotropic at the study scale. Spatial analysis shows that the spatial distribution of soil salinity is mainly controlled by structural factors, while stochastic factors accelerate its formation. Soil salinity generally exhibits the trend of increment at spring period across the study areas, and the variation amplitude of soil salinity is mostly less than 10.0 g·kg-1. The joint application of electromagnetic induction and GIS provides a reference for the survey and quality evaluation of soil resources at different scales, and it can be used as a guide for the decision-making and management of agricultural water-soil resources.