Biochar-induced migration of tetracycline and the alteration of microbial community in agricultural soils

Recently, biochar is widely used as a soil amendment to improve soil properties, which might affect the fate and behavior of contaminants in soil. In this study, we investigated the effect of biochar on the migration of tetracycline (TC) in soil and their combined impacts on microbiome. Due to the strong interaction between soil and TC, adsorption, rather than photolysis or biodegradation, was the dominating dissipation way of TC in soil. Moreover, biochar could promote the vertical migration of TC through the decreased soil bulk density and its lower adsorption capacity. After 90-day incubation, only slight impact of TC on soil bacterial community was observed due to the rapid dissipation of TC in soil, whereas more available C supply induced by biochar significantly altered bacterial community via the enhancement of copiotrophic bacteria. Besides, biochar could decrease the soil pH and thus change the composition of fungal community. The effect of TC on fungal community was partially counteracted by biochar, which could adsorb part of TC and thus decrease the contact of TC with microorganisms . This work will improve our understanding of the fate of organic pollutants and evolution of microbiome in soil where biochar servers as soil amendment.