Abstract: Understanding the geochemical character of groundwater is important for regional groundwater environment protection, ecological environment monitoring and study of biogeochemical processes of earth surface. This paper discussed hydrochemistry types and formation processes of groundwater, according to the physicochemical properties, chemical composition and evolved gas composition of groundwater in the central and southern Liaoning. There were six hydrochemistry types in the research areas, i.e. NaCa-HCO₃, CaMg-NO₃, Na-CO₃SO₄, CaMg-HCO₃, Ca-HCO₃, and Na-SO₄. Evolved gases mainly contain N₂, CO₂, CH₄ and He, indicating that the underground water was impacted by the materials of organic source and earth deep source. The underground water in some regions had been affected by agricultural production, and the hydrochemistry type was different from that of the natural underground water. The different hydrochemistry types of underground water in different regions were jointly controlled by reservoir depth, exposed position, fracture property, grain size and lithology. This study has an important significance for protecting the ecological environment of the central and southern Liaoning, and clarifying the chemical element migration pathway and mechanism of the supergene zone.

Key words: ectomycorrhizal fungi, soil propagule bank, Pinus bungeana