LAUSR

Abstract Clay has a positive influence on organic matter degradation and nitrogen conservation during chicken manure composting, but its effects on the diversity of antibiotic-resistant bacterial are unclear. The impact of the clay amendment (0% (T1), 2% (T2), 4% (T3), 6% (T4), 8% (T5) and 10% (T6) on the environmental risk of antibiotic-resistant bacteria abundance during chicken manure composting was investigated. The results showed that 4% clay increased the relative abundances of antibiotic-resistant bacterial, while 8% and 10% clay additions significantly reduced the total relative abundances of antibiotic-resistant bacterial in the compost, where the relative abundances of antibiotic-resistant bacterial was 0.46 log lower than the control. Clay mainly affects the distribution of antibiotic-resistant bacterial by influencing the relative abundances of Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes phylum. The maximum dosage of the clay amendment had a more persistent impact on the antibiotic-resistant bacterial community. However, bacterial abundance could be classified according to the composting time under diverse treatments. In the present study, the abundance of the antibiotic-resistant bacterial has a considerable impact on the alteration of the physicochemical parameters during composting. The correlations between the physicochemical parameters (temperature, carbon/nitrogen ratio, and gaseous emissions) and antibiotic-resistant bacterial were more significant than pH and germination index.