[Effects of DBP-imidacloprid Combined Pollution on Soil Bacterial Community]

In order to clarify the effects of plasticizers and pesticides on soil bacterial community characteristics, a pot experiment was designed to study the impacts of DBP, imidacloprid, and DBP + imidacloprid on growth indicators and bacterial communities of pakchoi. The results showed that DBP inhibited root length, fresh weight, plant height, root weight, and chlorophyll content of pakchoi, while appropriate amounts of imidacloprid promoted fresh weight, plant height, root weight, and chlorophyll content and alleviated the inhibitory effects of DBP on these growth parameters. On the first day of the experiment, compared with that of the control group, the Shannon index of the DBP-treated group decreased by 3.42%, that of the imidacloprid-treated group significantly increased by 2.00% (P<0.05), and that of the DBP + imidacloprid-treated group decreased by 0.68%. Compared with those under the DBP treatment, the DBP + imidacloprid treatment increased the Sobs and Shannon indexes. On the 30^th day of the experiment, compared with that under the control, the bacterial community Sob index decreased, while the Shannon index increased after treatments with DBP, imidacloprid, and DBP + imidacloprid. Pseudomonadota was significantly correlated with soil organic matter content and alkali-hydrolyzable nitrogen content (P<0.01), Actinomycetota was significantly correlated with soil organic matter content, and Acidobacteriota was significantly correlated with soil alkali-hydrolyzable nitrogen content (P<0.01). In addition, DBP pollution increased the abundance of functional groups related to human pathogens, and the addition of imidacloprid effectively reduced the abundance of these groups, thereby decreasing the risk of soil-borne diseases. The research results provide new insights into the environmental impacts of DBP and imidacloprid and offer a scientific basis for reducing health and safety risks of agricultural products and remediating farmland pollution.