Hydrogeochemical Evolutionary Mechanisms and Irrigation Suitability of Phreatic Water in a Cherry Cultivation Zone of China.

Groundwater serves as the primary water source for irrigation in cherry cultivation areas in northern China, where rainfall is scarce. A comprehensive investigation, discrimination of hydrogeochemical evolutionary mechanisms, and assessment of irrigation water quality are of great significance for ensuring the stability and safety of water use in the plain cultivation region. This study systematically investigates the integrated performance regularity of major factors controlling their evolutionary processes and the relationship between mineral saturation index (SI) and burial depth of quaternary rock based on the groundwater samples and surface water samples by multivariate analysis approaches, including correlation analysis, principal component analysis, Piper trilinear diagram, Gibbs diagrams, Gaillardet diagrams, geochemical ratio bivariate diagrams, the chloride alkalinity indices, and SI. The results reveal that water-rock interactions are the primary process of ion concentrations in the study region, primarily driven by the dissolution of minerals, such as silicate, halite, and gypsum. In addition, cation exchange and human activities, such as the application of fertilizer and pesticide, are also important factors altering the major ion chemistry of groundwater. No evident correlation was found between the SI and the depth of the phreatic aquifer within the 0-50 m depth range. While groundwater in the study area is generally suitable for agricultural irrigation with respect to sodium hazards, appropriate drainage systems should be established prior to irrigation to mitigate salinity hazard.