One-hundred and fifty five large-scale crop rice and root soil samples were collected in Nanchuan District of Chongqing, and some samples of corn, potato, tomato, rapeseed, plum and kiwifruit, and root soil were collected for testing and analysis. The bioavailability of the elements was characterized by bioconcentration factors. The effects of soil physical and chemical properties, soil composition, geological background, and crop types on the bioavailability of Cd were analyzed. The results showed that there was a certain degree of Cd exceeding the standard in rice and root soil in Nanchuan District, and the bioavailability of Cd was relatively low. Soil pH was the main controlling factor of Cd bioavailability, and the bioavailability was higher under acidic conditions. Plum, kiwi, and kiwifruit have weaker ability to enrich Cd. Therefore, it is possible to prevent heavy metal pollution in the soil and improve the quality of agricultural products by artificially regulating the pH of the field or adjusting the planting structure. The method can also be applied to the research of other soil heavy metals or health elements such as Se and provides a scientific basis for the safe use of land and the production of high-quality agricultural products.
Keywords: Cd; bioavailability; enrichment factor; influencing factors; quality of agricultural products.