Influence of turning frequency on removal of pathogens and antibiotic resistance genes from full-size sheep manure composting on the Qinghai-Tibet Plateau

Effectively removing pathogenic bacteria, viruses, and antibiotic resistance genes (ARGs) in livestock and poultry manure is essential for the safe utilization of these wastes. The aim of this study was to analyze the impacts of turning frequency on the pathogens, antibiotics, and ARGs during sheep manure composting at a practical scale on Qinghai-Tibet Plateau (QTP). This study set up three treatments for turning once every 2 d (T1), 4 d (T2), and 6 d (T3). Results showed that compared with T2 and T3, T1 increased the germination index and humus content by 3.0 %-13.5 % and 1.91 %-7.45 %, respectively. T1 effectively reduced the counts of Coliforms and Salmonella, as well as the abundance of pathogenic bacteria such as Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. It also decreased viral diversity and abundance. Notably, the removal rates of oxytetracycline, penicillin, cephalosporin C, and tylosin in T1 were increased by 9.14 %, 9.38 %, 12.6 %, and 12.5 %, respectively, compared to T3, and diminished the abundance of ARGs conferring resistance to macrolide-lincosamide-streptogramin, multidrug, bacitracin, tetracycline, and beta-lactam. Jeotgalicoccus, Corynebacterium, Herbinix, and Clostridium were the main hosts of ARGs in raw materials, while Pseudoxanthomonas, Luteimonas, Microbacterium, Alcanivorax, Devosia, and Pusillimonas were the main hosts in compost products. These findings provide a theoretical foundation and technical guidance for the harmless treatment and resourceful utilization of sheep manure on the QTP.