Quantitative analysis of spatial distribution pattern of soil salt accumulation in plough layer and shallow groundwater in the Yellow River Delta

In order to study the regularity of soil salt accumulation in plough layer caused by groundwater in the Yellow River Delta, GIS and the fundamentals and methods of geostatistics were applied to regionalize the study area based on the spatial distribution pattern of groundwater table and the criteria of critical water table. And for each sub-region, quantitative analysis was performed between groundwater mineralization and soil salt accumulation in plough layer at the spatial scale. Results indicate that groundwater table, groundwater mineralization and soil salinity in plough layer all exhibite moderate spatial variation, and the trends are all second order in both east-west and north-south directions. Owing to compound impact of structural and stochastic factors, groundwater table exhibites moderate spatial autocorrelation while the spatial autocorrelation of groundwater mineralization and soil salinity in plough layer are both weak. The distribution pattern of soil salinity in plough layer is positively correlated with that of groundwater mineralization to some extent, while it is negatively correlated with that of groundwater table. The quantitative analysis of groundwater mineralization and soil salinity in plough layer, which is performed at the spatial scale, show that soil salt accumulation is significantly correlated with groundwater mineralization while this correlation decreases with the increase of groundwater table, and the regularity analysis of soil salt accumulation in plough layer and groundwater mineralization would be more objective and accurate when sub-regions are adopted. The research results are of great significance for the mechanism, prediction and evaluation of the occurrence and development of soil salinization in the Yellow River Delta.