Effects of struvite-humic acid loaded biochar/bentonite composite amendment on Zn(II) and antibiotic resistance genes in manure-soil

•HMCC immobilized Zn(II) mainly by forming Zn3(PO4)2·4H2O and humic acid-zinc complex.•Soil pH and bio-Zn were significantly related to the abundance of ARGs.•The potential host bacteria for ARGs mainly belonged to the phylum Actinobacteria.•HMCC addition increased the diversity of bacteria community but reduced the abundance of Actinobacteria.•HMCC could be used as an environmentally friendly amendment in manure-soil.