Physicochemical properties and salinization characteristics of soils in coastal land reclamation areas: A case study of China-Singapore Tianjin Eco-City

Land salinization is a global environmental problem, and how to manage saline soils and promote healthy ecosystems has become a major challenge. China-Singapore Tianjin Eco-City is located in coastal land reclamation areas, so salinization is severe in this region. In this study, geostatistical methods, the ordinary kriging method, and principal component analysis were used. Vertical sampling was performed over three layers (0-20 cm, 20-40 cm, and 40-60 cm) at 184 locations within the study area to produce a total of 542 soil samples. It was found that areas with soluble salt contents greater than 3000 mg/kg account for over 90% of the study area, and high soluble salt content in surface layer soils is the dominant factor in soil salinization. Na⁺, Cl^-, and SO₄ ^2- are the primary control factors that determine the coefficient of variation of the soils' soluble salt content. Total salinity and Na⁺, Cl^-, SO₄ ^2-, K⁺, and Mg²⁺ reflect on the salinization of the soils, while effective phosphorus, available potassium, and soil organic carbon reflect on the state of soil nutrition. Based on our results, we proposed site-specific and scientific soil remediation and greening measures.