Guohua Hou

To comprehensively explore the research hotpots and trends in soil salinization in China, CiteSpace software (version 6.3.R1) was used to visualize the knowledge graph and bibliometric analysis of relevant literature from 2000 to 2024 in the China Knowledge Network (CNKI) database and Web of Science (WoS) database. Analysis of 1963 CNKI documents and 2134 WoS documents published by 249 units for annual publications, research institutions, authors, and keyword graph revealed that the annual publication volume of the literature in the field of salinization shows an upward trend and the volume of quality English publications is higher than that of Chinese. The cooperation network of authors and institutions had already been formed in the field. The cooperation among research institutes was stable, and a core group of authors had already been formed. Since 2020, “spectral index”, “machine learning”, “remote sensing inversion”, “spatial and temporal changes”, “inter-root”, “simulation”, “oasis”, “ rainy season”, and “soil water content” have become hot words in research. The visualization of spatial and temporal distribution of soil salts based on big data and artificial intelligence has become the focus of attention of the academic community. Therefore, the challenges of salinization should be better addressed through scientific and technological innovation and comprehensive measures. The results of the study are expected to provide scientific references for the field of salinization in China.

：In order to find out the hydrochemistry and salinization of shallow groundwater in coastal aquifers, 76 ground- and surface-water samples, contained phreatic upper water, phreatic water, confined water, river water and seawater were collected for major ion and isotope analysis(2H/18O, 14C). The results show that: (1) The phreatic upper groundwater changes along the general flowpath towards the coast from fresh(TDS <1 g/L), brackish (1–3 g/L) to saline (3–50 g/L). The phreatic water and first confined water are basically unchanged, but mainly saline water. (2) Shallow groundwater is mainly derived from atmospheric precipitation and undergoes significant evaporation processes. The phreatic upper groundwater is mainly derived from modern atmospheric precipitation recharge. The phreatic water and first confined water are mainly derived from precipitation replenishment during the warm period of the Holocene and some relict seawater. (3) The processes for salinity sources of the shallow groundwater are that oceanic evaporative salt formed during the transgression and retreat period since the late Pleistocene was dissolved by atmospheric precipitation and river water for many periods. The salt in phreatic upper water of the estuary area is also derived from modern seawater intrusion. Key words: coastal zone; groundwater; hydrochemistry; hydrogen and oxygen stable isotope; salinization _____________   Corresponding author. Qingdao Institute of Marine Geology, China Geologic Survey, Qingdao, 266071, PR China. E-mail address: gms532@163.com. This study was financially supported by the National Natural Science Foundation of China (41977173), China Geology Survey project(DD20189503) and National key research and development projects(2016YFC0402801)