Study on the Relationship Between Selenium and Cadmium Content and Physical and Chemical Properties of Vegetable Root Soil

Taking the soil-vegetable association in Guanshanhu District of Guizhou Province as the test material, the selenium（Se） and cadmium（Cd） content of vegetables, the Se and Cd content of soil and the main physical and chemical properties were studied by using the method of investigation and sampling to further understand the enrichment of Se and Cd in vegetables, the relationship between the main soil physical and chemical indexes and the content of Se and Cd in soil was clarified, in order to provide reference for the comprehensive utilization of Se-rich soil resource.The results showed that under the classification of physical and chemical properties at all levels, the average content of total Se in soil（0-20 cm） was higher than the standard of selenium-enriched soil(0.4 mg·kg^-1).Among the 46 collected vegetable samples, the Cd content did not exceed the limit specified by the National Food Safety Standard for Maximum Levels of Contaminants in Food（GB2762-2022）,and the exceedance rate was 0%.The safety level for Cd was considered high, and the Se content was not detected.Soil physical and chemical properties had a significant impact on the geochemical behavior of Se and Cd.Soil organic matter, pH, and AN were significantly correlated with soil Se content, while soil available potassium was highly correlated with soil Cd content.The relationships between soil organic matter, pH, and AN with soil Se content were demonstrated as a power function, exponential function, and linear function, respectively.The relationship between soil available potassium and soil Cd content was demonstrated as a linear function.The problem of ‘Se-rich soil not resulting in Se-rich crops’ was observed in the study area, which was attributed to the unclear relationship between total Se and available Se in the soil.Therefore, exploring the morphological characteristics and bioavailability of Se in soil is of great significance for the stable production of Se-rich agricultural products in future research.