Dynamics of Antibiotic Resistance Genes in Soil Chronically Fertilized by Swine Manure

For study the dynamics of antibiotic resistance genes (ARGs) in soil chronically fertilized by swine manure, a soil incubation experiment was conducted. The dynamic changes of ARGs and mobile genetic elements (MGEs) were investigated within 310 days. The impacts of soil water content and addition of biochar was studied. The results showed that long-term manure fertilization contributed to significant increase of ARGs and MGEs in soil. In soil chronically fertilized with manure amended with different treatments, ARGs and MGEs decreased exponentially with incubation time. The degration of ARGs and MGEs in soil was slower with added biochar. Higher water content could significantly enhance the degration of ARGs and MGEs. The significant correlation between ARGs and MGEs indicated that MGEs can serve as an indicator of ARG reduction in soil. The results revealed the dynamic changes of ARGs in contaminated farmland soils induced by the application of swine manure, providing basic data for risk assessment of ARG contamination in soils and scientific reference for antibiotic resistance control in China.