Characteristics of Soil Salinity in Representative Plastic Shed Vegetable Production Areas in Shandong Province, China.

Plastic shed vegetable (PSV) cultivation has become an important vegetable production system in China, which accounts for about 1/4 of the total vegetable production of China. Shandong is the largest facility vegetable growing area in China. Continued years of high-input, high-output planting methods have brought some problems to the surrounding environment. Salinization has not only affected the soil and groundwater environment, but also the growth of vegetables. A comprehensive understanding of soil salinization in plastic shed vegetable fields is important for the sustainable development of the vegetable farming industry. In this paper, random survey sampling was used to collect soil samples from representative PSV production areas in Shandong Province, and the soil salinization status, acidification status, salt ion composition, and the main causes of soil salinity were studied in the survey area. Our study found that the salinized soils (mild, moderate, and severe levels) in the surveyed areas accounted for 40% of the total samples, and the total soluble salt (TSS) increased with the increase of the planting years. After continuous planting for 10 years, the soil pH showed a downward trend, indicating that salinization and acidification occurred simultaneously. A significant positive correlation was observed between TSS and soil organic matter (SOM) (r = 0.4773**). Principal component analysis found that , , , , Ca²⁺, K⁺, Mg²⁺, and Na⁺ had higher positive loads on principal component 1, the factor loads were 0.557–0.927, and the contribution rate reached 34.928%. Correlation analysis also showed that TSS was positively correlated with the concentrations of these ions (P < 0.01). The soil salinization status should be closely monitored and regulated by regulatory authorities to improve environment and soil health through balanced fertilization, thereby improving the yield and quality of vegetables. [ABSTRACT FROM AUTHOR]